Urol Clin N Am 30 (2003) 751–763 Recurrent prostate cancer following external beam radiotherapy: Follow-up strategies and management Charles Catton, MD, FRCPC*, Michael Milosevic, MD, FRCPC, Padraig Warde, MD, FRCPC, Andrew Bayley, MD, FRCPC, Juanita Crook, MD, FRCPC, Robert Bristow, MD, PhD, FRCPC, Mary Gospodarowicz, MD, FRCPC Department of Radiation Oncology, University of Toronto, Princess Margaret Hospital, 610 University Avenue, Toronto, Ontario M5G 2M9, Canada Patients with early-stage prostate cancer who are treated with radical radiotherapy (RT) have an excellent prognosis, and although long-term survival is expected, many patients fail and will require further interventions. The optimal followup strategies to detect treatment failure and the optimal timing of further treatment are the subject of ongoing prospective trials. A well-designed follow-up strategy is part of an optimal management policy, and early detection of tumor recurrence also may improve the chance of re-treatment and salvage of a local or systemic relapse. The availability and efficacy of additional treatment govern the timing, frequency, and selection of follow-up investigations. This requires an understanding of the natural history of treated prostate cancer and the cost-effectiveness of therapy. There is no benefit in an intensive follow-up program if early intervention is not recommended and treatment is introduced only when recurrent disease is clinically apparent and symptomatic [1]. This article reviews the information on the follow-up strategies including detection and treatment of relapse of prostate cancer following radical external beam RT (EBRT) (Figs. 1 and 2). Identification of local relapse Because the prostate gland remains in situ after radical EBRT, the prostate-specific antigen (PSA) does not fall to undetectable levels as is seen after radical prostatectomy (RP). Rising PSA is the most common sign of recurrence after EBRT, but it may reflect local, regional, or distant failure, or a combination of the sites of failure. Digital rectal examination (DRE) with PSA determination are employed in post-EBRT follow-up, although Johnstone et al [2] determined that new information was provided by post-RT DRE in only 30% of abnormal examinations, and in 75% of these cases the findings were related to EBRT-induced rectal bleeding rather than to tumor recurrence. The measurement of PSA levels following EBRT is the most widely employed method of evaluating post-EBRT outcome in patients with localized prostate cancer, but the sensitivity and specificity of the method for predicting a clinically relevant outcome is less than perfect and is open to criticism [3,4]. Other follow-up tests, such as posttreatment biopsy of the prostate and functional imaging, may be used to supplement DRE and PSA in determining post-RT disease status, and these are discussed below. Serial PSA determinations * Corresponding author. E-mail address: charles.catton@rmp.uhn.on.ca (C. Catton). The serum PSA level is correlated to total tumor burden and the PSA level after treatment is a widely used surrogate endpoint of response 0094-0143/03/$ - see front matter Ó 2003 Elsevier Inc. All rights reserved. doi:10.1016/S0094-0143(03)00051-X 752 C. Catton et al / Urol Clin N Am 30 (2003) 751–763 Fig. 1. (acrobat figure 030J). Follow-up flow chart for men treated with radical EBRT for prostate cancer. in prostate cancer. The value of PSA response has been documented in a number of studies [5–9], although the use of adjuvant hormone therapy makes the interpretation of PSA levels after RT unreliable because the PSA production is under hormonal control and the value of PSA may not reflect directly the presence or absence of tumor. The decline of PSA following RT is slow and normally takes 6 to 24 months or more, and the definition of response or failure based on the PSA levels following treatment is referred to as ‘‘biochemical response or failure.’’ Biochemical response may be defined as ‘‘PSA nadir’’ or ‘‘PSA failure.’’ In 1997, the American Society for Therapeutic Radiology and Oncology (ASTRO) consensus panel published a consensus statement on the definition of PSA failure [10]. The ASTRO consensus panel agreed on four guidelines [10]: 1. Biochemical failure is not equivalent to clinical failure. 2. Three consecutive increases in PSA is a reasonable definition of biochemical failure, with the date of failure reported as the midpoint of the nadir PSA and the first of the three consecutive rises. Three consecutive rises were adopted to prevent classification of patients with fluctuating PSA from being classified as treatment failures. Fig. 2. (acrobat figure 031J). Flow diagram for the management of clinical local failure or biochemical failure of localized prostate cancer following radical EBRT. C. Catton et al / Urol Clin N Am 30 (2003) 751–763 3. No definition of PSA failure has been shown unequivocally to be a surrogate for clinical progression or survival. 4. Although nadir PSA is a useful factor, no absolute level is a valid cutoff point in deciding successful or unsuccessful treatment outcome. Although these criteria generally correlate well with clinical outcome [8,11], they have many limitations. Taylor et al [12] reported that the specificity and sensitivity of a rising PSA to predict a clinically meaningful failure such as a local recurrence, distant recurrence, or initiation of unplanned hormone therapy or RP is related to the proportional magnitude of the PSA rise above nadir levels and the steepness of the slope of the rise (the PSA doubling time [PSADT]). For example, proportionally small consecutive rises measured over a short interval may have a benign cause and be misclassified as biochemical disease progression. In another scenario, any gradually progressing tumor may have a slowly rising PSA trend that is obscured by occasional decreases in PSA levels, thus resulting in a much-delayed recognition of treatment failure. PSA nadir The PSA nadir is the lowest level of PSA measured after RT. A PSA nadir predicts a subsequent biochemical and clinical failure [7], but the nadir level is not in itself an indicator of disease remission or relapse. Longer interval from treatment to PSA nadir positively correlates with freedom from metastatic disease [6,7], and PSA progression immediately following RT is a strong indicator of the presence of systemic metastases, presumably because in this situation PSA production continues unimpeded during and immediately after EBRT. PSA bounce A PSA bounce has been defined as an initial posttreatment increase in PSA of greater than 0.4 ng/mL or greater than or equal to 15% of the previous value over a 6-month period within 60 months of therapy that subsequently decreases to prebounce baseline levels [13–15] or lower. A PSA bounce has been identified in 12% to 33% of patients treated with EBRT [14,15], and the mean time to PSA bounce was found to be as long as 9 months [15]. The cause has not been defined, but is speculated as possibly being due to ejaculation or 753 instrumentation [13]. A PSA bounce is not predictive of future biochemical failure and should not be used as a sole indicator of relapse, although the risk of relapse is higher in patients who exhibit multiple episodes of PSA fluctuation [14]. Post-RT prostate biopsy Crook et al [16] proposed that routine, systematic, transrectal, ultrasound-guided prostate biopsies might be an effective way of determining post-RT local tumor control. They observed that sequential positive biopsies often converted to negative over time, and recommended that the optimal time to biopsy was 24 to 30 months postRT [17]. Several other reports of EBRT for localized prostate cancer have included post-RT biopsies with the outcome assessment [18–20]. Despite the attractiveness of using post-RT biopsies to determine local control, and the demonstrated interest in this procedure, experience has shown that correctly identifying viable tumor in biopsies of irradiated prostate is not straightforward. In addition to the problem of correctly timing the biopsies after treatment, the diagnosis of complete response is difficult, with 3% to 40% of post-RT biopsies remaining as indeterminate, even with expert evaluation [9,21,22]. Furthermore, there is significant interobserver variability in reporting positive post-RT biopsies among expert uropathologists, and poor agreement of expert pathologists with nonexpert pathologists [21]. Immunohistochemical tumor staining for PSA, high—molecular-weight keratin, and proliferative cell nuclear antigen have been reported to improve the sensitivity and specificity of reporting positive post-RT biopsies [23], as does correlation of biopsy status with the post-RT PSA nadir [24]. However, in spite of the limitations, posttreatment biopsy remains a valuable tool for selecting patients for local salvage therapy. In fact, retreatment with a local ablative procedure should not be considered without a positive prostate rebiopsy. A wider experience with the technique is required, and the criteria for the diagnosis of carcinoma in post-RT biopsies need to be refined further and applied uniformly before re-biopsy can be adopted as a routine method for assessing treatment response [21,25]. Imaging Although the assessment of the response to treatment and early detection of recurrence in 754 C. Catton et al / Urol Clin N Am 30 (2003) 751–763 prostate cancer are driven completely by serial serum PSA measurements, the site of recurrence cannot be determined by PSA and should be assessed by clinical examination and imaging, recognizing that standard imaging is likely to be negative and should not be done unless the patient has a Gleason score greater than 7 or a PSA greater than 50 ng/mL [26]. Radioisotope bone scans Skeletal imaging using 99mtechnetium-labeled diphosphonate is the most widely used technique for the detection and surveillance of prostate cancer to the bones [27]. Because a PSA rise usually antedates the detection of bone metastases in patients with prostate cancer, routine bone scans are not recommended as part of follow-up [28,29]. The bone scan should be used to help differentiate local recurrence from metastatic spread in patients with a rising PSA [27], although it has been demonstrated that for a PSA of less than 20 ng/mL and a Gleason score greater than 7, or for a PSA of less than 50 ng/mL and a Gleason score less than 8, a bone scan has less than 10% likelihood of being positive [26]. Because they are not useful, bone scans should not be performed in patients with very low PSA levels. imaging is not recommended as part of routine follow-up. For the investigation of a patient with a rising PSA after EBRT, preliminary evidence suggests that the technique is more sensitive and specific than is CT or MRI in identifying patients with nodal metastases. The very limited experience with capromab pendetide imaging for restaging patients treated with EBRT has shown it to be of value in making management decisions [32,33], but wider availability and more experience with the technique will be required before capromab pendetide imaging can be considered as a substitute for these standard staging investigations. Positron emission tomography [18F]fluorodeoxyglucose positron emission tomography (FDG PET) is a common method for imaging the metabolic activity of cancer. FDG PET scanning is valuable for the identification of metastases in a variety of tumors, although the low cellular uptake rate of FDG in prostate cancer has limited the usefulness of the technique for staging and follow-up for adenocarcinoma of the prostate [34,35]. More effective radiotracers such as [18F]flurocholine are under investigation and may improve the ability of PET to detect prostate cancer metastases [34,36], but at present PET scanning should not be used routinely for prostate cancer staging or follow-up. Capromab pendetide (ProstaScint) imaging Capromab pendetide (ProstaScint) is the conjugated form of a murine immununoglobulin G1 monoclonal antibody directed against prostatespecific membrane antigen (PSMA). 111Indium capromab pendetide is capable of identifying bone and soft tissue disease in patients with known metastases [30], and it is approved only for imaging of soft-tissue disease. A recent comparison of capromab pendetide imaging to CT or MRI for the diagnostic assessment of prostate cancer in 51 surgically explored patients demonstrated that capromab pendetide had a sensitivity of 75% in detecting nodal involvement compared with 20% for CT or MRI. Specificity and positive predictive value for capromab pendetide imaging was 86% and 79%, respectively, compared with a specificity and positive predictive value of 68% and 31% for CT or MRI imaging [31]. Imaging with capromab pendetide is challenging technically, and requires specific training to read the images [31], and routine capromab pendetide Treatment of relapse Salvage local therapy Hormonal ablative therapy has a long history of effectiveness in the management of relapsed prostate cancer and in a recent patterns of practice report [37], 93% of patients who received secondary therapy after EBRT were treated with hormonal ablative therapy. The numerous reasons for the popularity of this approach include the high response rate to therapy, the ease of access to treatment, the relative lack of associated serious toxicity, and patient preference. In addition, clinical factors such as advanced patient age at relapse and advanced disease extent at presentation or at relapse may make other, more aggressive approaches to salvage therapy less suitable. Clearly, there also is a role for curative local salvage treatment in selected individuals, although this use remains controversial, due largely to many unresolved issues in the natural C. Catton et al / Urol Clin N Am 30 (2003) 751–763 history of disease progression in these patients, and especially in accurately defining those patients who have a high likelihood of having an isolated local recurrence of disease. Patients with locally recurrent disease may be candidates for RP, cryosurgery, and brachytherapy, but these treatments are being used infrequently and it is difficult to compare the outcomes in these case series with the outcomes following conservative management. These series tend to have carefully selected patients and include only a small proportion of men who relapse after RT. Even so, only 35% to 50% of these patients will have prolonged biochemical disease-free survival [38,39]. The curative potential of these salvage local therapies is poorly documented. Who should be considered for salvage local therapy after RT? The individual most likely to benefit from ablative local treatment after failure of radical RT will have an anticipated life span of 10 years or more, a proven local recurrence, and a low probability of harboring micrometastatic disease. Because biochemical failure after RT can be due to local recurrence, distant recurrence, or both, biopsy proof of a local recurrence is essential, and restaging investigations looking for nodal or bone metastasis should be negative. The likelihood of success for local salvage therapy is dependent on the same risk factors as is the success of RT. A patient with a low pre-RT Gleason score, low PSA, and low initial clinical stage is least likely to fail because of the low risk of micrometastases, and therefore is most likely to benefit from a second attempt at a cure. In addition to the pre-RT risk factors, the timing of biochemical relapse after RT and PSADT both have been shown to be useful in predicting the pattern of failure after RT [40–42]. Sartor et al [42] reported the outcome of 400 patients with localized prostate cancer treated with radical RT between 1987 and 1994. With a median follow-up of 3 years, 234 patients (58.6%) had rising PSA values, 38 patients (9.7%) developed local failure, and 23 (5.8%) developed distant failure. On multivariate analysis, rapid PSADT was found to predict for metastatic rather than for local failure. Thirtyseven patients had a PSADT of less than 6 months and 17 (46%) of these patients developed distant metastasis as compared with only 4 (8%) who developed local relapse. Patients with a PSADT of 755 less than 6 months had an 8.5 fold increased odds of distant failure as opposed to local failure compared with patients with a doubling time of 6 to 12 months. Lee et al [41] reported on the pattern of failure after definitive RT in 459 patients with localized disease and found that PSADT (<12 months) and a short interval from the end of treatment to PSA elevation (<12 months) were significant independent predictors of distant metastases. Given the potential for significant local side effects of re-treatment, local salvage therapy should likely be considered only for patients with a long life expectancy who would prefer the option of a potentially curative treatment to the option of surveillance or longterm hormonal ablation. Patients most likely to respond to re-treatment will have clinical stage T1/T2 at initial presentation and at relapse, PSADT of greater than 6 months, and an interval between primary treatment and relapse of greater than 1 year. In addition, the serum PSA presalvage treatment should be less than 10 ng/mL and the initial Gleason score should be 7 or less. Salvage RP RP has not been accepted widely as salvage therapy for local recurrence after radiation therapy because of the morbidity and high recurrence rates. Reports from the pre-PSA era show a 40% to 50% incidence of postsurgery incontinence, 100% impotence, and a substantial incidence of serious bowel and rectal injury [43– 46]. In the modern era, with relapse being detected earlier based on rising PSA, a number of series reported more favorable outcomes. Pisters et al [47] reported on 13 patients treated with salvage RP between 1995 and 1999. All received a continent catheterizable reconstruction to prevent urinary incontinence, and 9 of 13 remain disease-free 6 to 48 months after surgery. Gheiler et al [48] reported results in 30 patients treated with salvage RP between 1992 and 1997 at Wayne State University. With a mean follow-up of 36 months, 15 patients (50%) had no evidence of biochemical disease progression. Only 15 patients (50%) were continent; mild incontinence was present in 8 patients (26%) and severe incontinence was seen in 7 patients (23%). Vaidya and Soloway [49] reported the outcome of six patients who underwent salvage RP at the University of Miami between 1995 and 2000. Androgen deprivation therapy was given preoperatively in five of these patients. With a mean follow-up of 756 C. Catton et al / Urol Clin N Am 30 (2003) 751–763 27 months, biochemical failure has occurred in only one patient. All six patients are impotent, five are continent, and one patient has mild stress incontinence. Although these results may be encouraging, it is impossible to generalize them, given the degree of patient selection in these series. Patients choosing RP as salvage local therapy should be informed of the potential morbidity, particularly the risk of clinically significant incontinence, and surgery optimally should be performed in a center that has experience with this approach. a posttreatment America Urological Association symptom score greater than 20. Overall satisfaction with cryotherapy was reported by only 33% of patients. Cryosurgery has been approved by the Centers for Medicare and Medicaid Services as the only treatment specifically approved for the indication of recurrent local cancer after radiation. However, the significant complication rates after treatment and the lack of proven efficacy have limited its use largely to specialized centers. Interstitial brachytherapy Salvage cryotherapy Initial results of cryotherapy as salvage therapy after failure of RT were disappointing. Control rates were less than 25% and significant incontinence was seen in more than 40% of patients [50]. Advances in cryosurgical technique have improved these results with long-term incontinence rates now being reported as less than 10% [51–53]. Biochemical disease-free survival rates are in the 30% to 40% range, with better results seen in patients with low-grade T1/T2 disease and PSA less than 10 ng/mL before treatment [51,54] Chin et al [51] reported results in 118 patients treated between 1994 and 1999. With a median follow-up of 19 months, the biochemical no evidence of disease rate at 4 years was 34%. Severe incontinence was noted in eight patients (6.7%) and rectourethral fistula occurred in four patients (3.3%). In a recent update of the MD Anderson data, Izawa et al [54] reported a 5-year disease-free survival of 40% in 131 patients treated between 1992 and 1995 (median follow-up = 4.8 years). As in other series, patients with a precryotherapy Gleason score greater than 9, PSA greater than 10 ng/mL, and advanced clinical stage did poorly. In addition, patients with androgen-independent local progression did worse compared with those with androgen-dependent disease [54]. Quality of life is compromised after cryotherapy in a substantial number of patients. In a patient-based questionnaire administered to 150 patients (112 questionnaires returned, 74%) at MD Anderson Cancer Center, 72% of patients reported some degree of dribbling or leakage when asked to describe bladder control [55]. Forty-four percent of patients reported problems with perineal pain, and pain interfered with normal daily activity in 38% of patients. Treatment without an effective urethral warming catheter was associated with urinary incontinence, perineal pain, tissue sloughing, and Grado [56] and Grado et al [57] reported on a series of 49 men treated with salvage brachytherapy, using either iodine 125 or palladium 103 for full-dose permanent transperineal seed implants. Median follow-up was 64 months. Initial RT dose was 66 Gy (range 20–70 Gy) completed at a median interval of 41.7 months previously. Patients were not rigorously selected for having a high chance of successful local salvage. Seventyone percent had presented with an initial stage B2C tumor. Moderately differentiated tumors had been documented in 53% and poorly differentiated tumors had been documented in 34%. Only half had baseline PSA levels available from the time of initial diagnosis; the median value was 26.4 ng/mL. Despite the high-risk profile of the population, the actuarial, biochemical, diseasefree survival at 3 and 5 years following salvage brachytherapy was 48% and 34%, respectively. More importantly, the results of these studies [56,57] demonstrate the feasibility of salvage brachytherapy in terms of toxicity. Posttreatment irritative and obstructive urinary symptoms were self-limited and managed with alpha-blockers. Transurethral resection of the prostate (TURP) was performed in 14%, 4% experienced persistent gross hematuria, 6% experienced penile dysuria, and 4% had rectal ulcers. One of these latter patients required colostomy after aggressive rectal biopsies. Incontinence (at least one pad per day more than 6 months after the procedure) was documented in 6%, all of who had a postbrachytherapy TURP. Only one patient who previously was potent reported diminished sexual function. The authors [56,57] now recommend avoidance of TURP and management of irritative and obstructive urinary symptoms with alpha-blockers and intermittent self-catheterization. Beyer [58] reported on 17 patients treated with salvage permanent seed prostate brachytherapy. Those C. Catton et al / Urol Clin N Am 30 (2003) 751–763 patients with a low-grade tumor at the time of salvage had 83% freedom from second relapse as compared with 30% for those patients with highgrade tumors. Salvage brachytherapy compares favorably with other potentially curative salvage options for locally recurrent prostate cancer after conventional-dose RT. There is no experience with its use after modern external RT techniques that employ prostate doses greater than 70 Gy [57], and the potential for increased rectal and urinary toxicity exists with re-treatment following high-dose EBRT. The ideal patient for retreatment with brachytherapy should have presented originally with a tumor likely to be confined to the prostate (T1c/T2a, Gleason 6, PSA<10 ng/mL), and should have biopsy evidence of residual lowgrade prostate carcinoma with minimal radiation effect [24]. Because early biochemical failure is likely to be associated with a distant component, a disease-free interval of at least 12 months and preferably 24 months is more likely to be associated with purely local recurrence [6]. Finally, good tolerance of the initial RT with an absence of rectal or urinary toxicity is advisable. Hormonal therapy for progression following RT It has been known for many years that prostate cancer is a hormonally responsive disease and that withdrawal of testosterone leads to rapid regression of disease [59]. The mechanisms underlying the dramatic response to androgen withdrawal that frequently is seen clinically are complex and interrelated, and include increased apoptosis, inhibition of angiogenesis, and altered expression of hormonally responsive genes. Most men who recur following RT for prostate cancer will, at some point in their disease, require treatment with androgen suppression. Historically, the diagnosis of recurrence was most likely to be made on the basis of new urinary symptoms, due to progressive local disease or musculoskeletal pain from bone metastases. However, rising PSA in the absence of symptoms now provides an early sign of recurrence following RT and precedes clinical evidence of failure by many years. Many men at the time of PSA progression are not candidates for potentially curative salvage treatments, but may nevertheless live long, productive lives with slowly progressive disease. Therefore, management recommendations at the time of recurrence must focus on extending the symptom-free interval and improving survival, while maintaining a high quality of life. 757 Surgical or medical castration produces a high likelihood of prolonged PSA control in the majority of men. The combination of a nonsteroidal antiandrogen and castration to produce ‘‘total androgen blockade’’ [60] yields only minimal improvement in survival compared with castration alone [61–63]. Furthermore, increased cost, more frequent and bothersome side effects, and a general reduction in quality of life may overshadow the small benefit. Short-course neoadjuvant androgen suppression, which is commonly prescribed before RT, does not compromise the response to subsequent salvage hormonal treatment administered for disease progression [64]. The type and severity of the side effects from androgen suppressive therapy vary depending on the specific treatment and its mechanism of action, but commonly include vasomotor hot flashes, loss of libido, erectile dysfunction, breast pain and gynecomastia, mood swings and anxiety, anemia, osteoporosis that predisposes to fractures, loss of muscle mass, and altered glucose and lipid metabolism. Vasomotor symptoms and impaired sexual performance affect a large proportion of men treated with a luteinizing hormone-releasing hormone (LHRH) agonist. Nonsteroidal antiandrogens—particularly bicalutamide—may preserve erectile function at the expense of a higher incidence of breast symptoms [65]. The implications of long-term androgen ablation on bone, lipid, and glucose metabolism, although minimal in the setting of known metastatic disease in which survival is limited, are potentially much greater in otherwise healthy men who begin treatment for a rising PSA following RT and are expected to live for many years. Timing of hormonal therapy Men who develop clinical local progression or metastases following RT for prostate cancer require immediate androgen suppression by orchiectomy or with an LHRH agonist. In the case of the latter, pretreatment with an antiandrogen is required to prevent tumor flare and worsening of symptoms. However, this is now a rarely seen presentation of relapse. The majority of patients is followed with serial PSA measurements and develops PSA failure with no evidence of clinical disease. The optimal time to begin hormonal therapy in an asymptomatic man with PSA failure alone is not know, but, in practice, most men in North America opt for earlier rather than later 758 C. Catton et al / Urol Clin N Am 30 (2003) 751–763 treatment. The choice may differ from individual to individual depending on how each weighs the potential benefits versus the side effects. Some men or their families experience considerable anxiety and emotional distress knowing that a rising PSA represents progressive cancer and demand active treatment immediately upon diagnosis of recurrence. Others prefer to defer treatment and exposure to possible side effects for as long as possible. There is increasing evidence from clinical studies that ‘‘early’’ intervention with hormonal therapy is beneficial, compared with later treatment at the time of symptom development. This is likely due to an effect of hormonal treatment on gene expression in prostate cancer, with delayed emergence of clinically aggressive and metastatic phenotypes. Messing et al [66] demonstrated a survival advantage to immediate medical or surgical castration in men with node-positive prostate cancer identified at the time of radical prostatectomy compared with initial observation. Bolla et al [67,68] described improved survival in patients with locally advanced or high-grade prostate cancer treated with RT and hormonal ablation for 3 years, compared with RT initially and hormonal treatment at the time of disease progression. The UK Medical Research Council Prostate Cancer Working Party Investigators Group [69] studied 934 asymptomatic men with previously untreated locally advanced or metastatic prostate cancer, and randomized them to receive either immediate surgical or medical castration or initial observation and the same treatment at the time of symptomatic progression. Men who received immediate treatment had a significantly lower risk of developing urethral obstruction, metastatic disease, pain due to bone metastases, pathologic fracture, or spinal cord compression. There also was an advantage of immediate treatment with respect to both overall and disease-specific survival, especially in men without metastases. This study has been criticized because PSA follow-up was not available (given that the study was initiated in 1985 before the routine use of PSA), clinical follow-up of patients was erratic, and a small proportion of patients on the delayedtreatment arm died of progressive prostate cancer without receiving hormonal treatment. Nevertheless, it provides strong support for early hormonal treatment in men with recurrent prostate cancer after RT who are anxious to obtain the maximal benefit of this treatment, and are not bothered by the attendant side effects and potential reduction in quality of life. The definition of ‘‘early treatment’’ in the context of modern medical practice, where progression after RT most commonly is diagnosed on the basis of serial rises in PSA, is ill defined. It is likely that men participating in the MRC study had a broad spectrum of locally advanced and occult metastatic disease and, extrapolating from more recent experience, a correspondingly broad range of PSAs ranging from minimally abnormal to very high values that would now be viewed as a clear indication for immediate treatment. In contrast, men with progression following RT frequently have normal or minimally elevated PSAs that increase very slowly over time. It is not known whether beginning hormonal treatment immediately at PSA progression offers any advantage compared with careful follow-up and later initiation of treatment at some ‘‘trigger’’ point before the development of symptoms. This is particularly important in light of the young age of many patients undergoing RT, their long anticipated survival, and the side effects of hormonal treatment. The European Organization for Research and Treatment of Cancer (EORTC) 30943 study, which is randomizing men with a rising PSA to immediate versus delayed hormonal treatment, should help to answer this question. Currently, the most frequent indication for beginning hormonal treatment in men who fail RT is the rate of PSA rise. Short PSADTs predict metastatic disease and a shorter interval to the development of symptoms [70,71]. Sylvester et al [60] surveyed urologists and radiation oncologists who treat prostate cancer and found that 65% to 70% used a short PSADT as the main indication for hormonal therapy following RT. Most used a threshold doubling time of 6 months or less, although almost 25% recommended treatment at a threshold doubling time of 12 months or less. The remaining 30% to 35% relied on either the absolute PSA value, or used the ASTRO definition of failure to recommend treatment. Intermittent hormonal therapy The development of hormone-refractory disease remains a major problem in the management of men with prostate cancer. Although the rate of response to initial hormone treatment is high, most men develop progressive disease despite continued antiandrogen therapy at a median interval of about 2 years from the start of treatment [62,63]. The duration of hormone responsiveness may be C. Catton et al / Urol Clin N Am 30 (2003) 751–763 longer in men who have small-bulk disease when treatment is initiated. Once hormone refractory disease becomes clinically evident on the basis of a rising PSA or the development of new symptoms, the management options for patients are limited. Changes in the type of hormone treatment may produce secondary responses, but the duration of response usually is short lived. Therefore, treatment strategies that prolong the interval of hormone dependence have the potential also to prolong survival and improve quality of life. There is preliminary evidence that intermittent androgen suppression—which involves sequential periods of androgen suppression followed by withdrawal of treatment and androgen recovery— has the potential to delay the molecular and genetic changes that lead to hormone resistance, extend the duration of response to hormone therapy, and reduce side effects. Several, small, phase 2 clinical studies now have been reported, most of which used PSA as the indication for starting and stopping treatment with an LHRH agonist [72–74] Treatment and off-treatment intervals in these studies have been approximately equal, typically ranging from 6 to 9 months in duration [72–74]. Testosterone recovery occurred in the majority of men while off treatment, and was associated with improved libido and sexual capacity in those who were potent before beginning treatment, as well as an overall improvement in quality of life. There was a suggestion of delayed development of hormone resistance relative to continuous androgen suppression. However, the results in this regard are very difficult to interpret, given differences in patient selection and the multitude of factors that can affect the duration of hormonal response, including the extent of disease at the time that treatment is initiated. Intermittent androgen suppression may be particularly well suited to men with PSA progression alone following EBRT, who may survive 10 years or more with slowly progressive disease. It has the potential to extend the clinical progression-free interval with minimal side effects and cost. However, there is insufficient evidence at present to recommend intermittent therapy as routine treatment. Prolonged hormone responsiveness has not been documented rigorously in the clinical domain, and the effect on survival is not known. Furthermore, intermittent hormone therapy may lead to repeated swings in symptoms, libido, sexual capacity, and general quality of life that some men may find intolerable compared 759 with the predictable steady-state of continuous treatment. The National Cancer Institute of Canada with the collaboration of Intergroup is conducting a phase 3 randomized trial of intermittent versus continuous androgen ablation for asymptomatic men with a rising PSA following RT and no clinical or radiographic evidence of metastatic disease that will provide answers to these important questions. Antiandrogen monotherapy Although most men who require androgen suppression for prostate cancer undergo either surgical or medical castration as a component of their treatment, there is interest in exploring alternate treatments that produce a more acceptable side-effect profile and therefore greater longterm tolerance and compliance. Treatment with a nonsteroidal antiandrogen alone, particularly bicalutamide, has the potential to maintain potency at the expense of an increased likelihood of gynecomastia and breast pain [65,75–77], a trade-off that many men would accept. There also is increasing clinical evidence to indicate that bicalutamide alone may preserve bone density relative to castration [78,79]. However, antiandrogens may yield inferior long-term disease control in some circumstances relative to castration because of secondary elevation of serum testosterone levels that overcomes the competitive blockade of androgen receptors. Several randomized clinical studies [75–77] have evaluated treatment with bicalutamide alone as a single agent relative to castration. A bicalutamide dose of 150 mg daily was used in many of the studies. In general, the results have shown the survival of men with metastatic disease to be inferior with bicalutamide compared with castration. However, the results in men with locally advanced, nonmetastatic disease have been equivalent. The pooled results of three, large, randomized studies of bicalutamide 150 mg daily comprising over 8000 patients showed that 80% to 90% of men developed breast toxicity within 6 months of beginning bicalutamide, and that 15% of men abandoned treatment because of intolerable breast symptoms. Breast pain resolved within 1 year in the majority of men stopping bicalutamide. However, resolution of gynecomastia was less predictable and inversely influenced by the duration of prior treatment. There was a low incidence of impotency compared with controls, and a low incidence of vasomotor symptoms [65]. 760 C. Catton et al / Urol Clin N Am 30 (2003) 751–763 There have been no completed randomized studies of single-agent bicalutamide in men with a rising PSA following RT for prostate cancer. Nevertheless, the available evidence suggests that this may be appropriate treatment in those who wish to maintain potency and can tolerate the breast side effects. Summary All patients who undergo curative therapy for prostate cancer should be followed for a prolonged period of time to determine tumor control and treatment toxicity for quality assurance purposes. Follow-up duties may be reasonably shared between the oncologist and the family doctor or urologist; however, it is probable that some follow-up information specific to the irradiated patient will be lost unless the oncologist maintains regular contact with the patient, especially in the first 5 years of follow-up when late radiation effects are most likely to appear. There is no strong evidence that patients stop being at risk for recurrence at any time after treatment, and because PSA testing is an accurate, simple, and inexpensive method of determining post-RT tumor status, it is recommended that periodic PSA measurements be continued for life. In the absence of a rising PSA, all other tests and visits are unnecessary to determine post-RT tumor control. Because DRE has been shown to be of limited utility in follow-up of irradiated patients, it should be possible to effectively follow patients remotely. This could be done by asking patients to have PSA tests done, forward the results to their physicians, and report treatment toxicity when it occurs. Only abnormal results would trigger an office visit. This strategy is being evaluated in clinical trials. The alternative is to delegate the follow-up to the primary-care physician with guidelines as to when referral back is required. Follow-up frequency, and the most beneficial follow-up investigations vary from scenario to scenario, and are influenced by the likelihood of relapse, time to relapse, and planned intervention. These decisions are influenced in turn by the initial presentation—either with high or low risk factors—and by the patientÕs general state of health at completion of EBRT. Effective follow-up also requires active patient cooperation that only can be achieved after discussion of the goals of follow-up with the patient and with the patientÕs full understanding of the process. 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