Survival of patients who had salvage castration after failure on bicalutamide monotherapy for stage (D2) prostate cancer

Non-steroidal antiandrogen monotherapy compared with luteinising hormone-releasing hormone agonists or surgical castration monotherapy for advanced prostate cancer

BACKGROUND

Non-steroidal antiandrogens and castration are the main therapy options for advanced stages of prostate cancer. However, debate regarding the value of these treatment options continues.

OBJECTIVES

To assess the effects of non-steroidal antiandrogen monotherapy compared with luteinising hormone-releasing hormone agonists or surgical castration monotherapy for treating advanced stages of prostate cancer.

SEARCH METHODS

We searched the Cochrane Prostatic Diseases and Urologic Cancers Group Specialized Register (PROSTATE), the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, Web of Science with Conference Proceedings, three trial registries and abstracts from three major conferences to 23 December 2013, together with reference lists, and contacted selected experts in the field and manufacturers.

SELECTION CRITERIA

We included randomised controlled trials comparing non-steroidal antiandrogen monotherapy with medical or surgical castration monotherapy for men in advanced stages of prostate cancer.

DATA COLLECTION AND ANALYSIS

One review author screened all titles and abstracts; only citations that were clearly irrelevant were excluded at this stage. Then, two review authors independently examined full-text reports, identified relevant studies, assessed the eligibility of studies for inclusion, assessed trial quality and extracted data. We contacted the study authors to request additional information. We used Review Manager 5 for data synthesis and used the fixed-effect model for heterogeneity less than 50%; we used the random-effects model for substantial or considerable heterogeneity.

MAIN RESULTS

Eleven studies involving 3060 randomly assigned participants were included in this review. The quality of evidence is hampered by risk of bias. Use of non-steroidal antiandrogens decreased overall survival (hazard ratio (HR) 1.24, 95% confidence interval (CI) 1.05 to 1.48, six studies, 2712 participants) and increased clinical progression (one year: risk ratio (RR) 1.25, 95% CI 1.08 to 1.45, five studies, 2067 participants; 70 weeks: RR 1.26, 95% CI 1.08 to 1.45, six studies, 2373 participants; two years: RR 1.14, 95% CI 1.04 to 1.25, three studies, 1336 participants), as well as treatment failure (one year: RR 1.19, 95% CI 1.02 to 1.38, four studies, 1539 participants; 70 weeks: RR 1.27, 95% CI 1.05 to 1.52, five studies, 1845 participants; two years: RR 1.14, 95% CI 1.05 to 1.24, two studies, 808 participants), compared with medical or surgical castration. The quality of evidence for overall survival, clinical progression and treatment failure was rated as moderate according to GRADE. Predefined subgroup analyses showed that use of non-steroidal antiandrogens, compared with castration, was less favourable for overall survival, clinical progression (at one year, 70 weeks, two years) and treatment failure (at one year, 70 weeks, two years) in men with metastatic disease. Use of non-steroidal antiandrogens also increased the risk for treatment discontinuation due to adverse events (RR 1.82, 95% CI 1.13 to 2.94, eight studies, 1559 participants), including events such as breast pain (RR 22.97, 95% CI 14.79 to 35.67, eight studies, 2670 participants), gynaecomastia (RR 8.43, 95% CI 3.19 to 22.28, nine studies, 2774 participants) and asthenia (RR 1.77, 95% CI 1.36 to 2.31, five studies, 2073 participants). The risk of other adverse events, such as hot flashes (RR 0.23, 95% CI 0.19 to 0.27, nine studies, 2774 participants), haemorrhage (RR 0.07, 95% CI 0.01 to 0.54, two studies, 546 participants), nocturia (RR 0.38, 95% CI 0.20 to 0.69, one study, 480 participants), fatigue (RR 0.52, 95% CI 0.31 to 0.88, one study, 51 participants), loss of sexual interest (RR 0.50, 95% CI 0.30 to 0.83, one study, 51 participants) and urinary frequency (RR 0.22, 95% CI 0.11 to 0.47, one study, 480 participants) was decreased when non-steroidal antiandrogens were used. The quality of evidence for breast pain, gynaecomastia and hot flashes was rated as moderate according to GRADE. The effects of non-steroidal antiandrogens on cancer-specific survival and biochemical progression remained unclear.

AUTHORS' CONCLUSIONS

Currently available evidence suggests that use of non-steroidal antiandrogen monotherapy compared with medical or surgical castration monotherapy for advanced prostate cancer is less effective in terms of overall survival, clinical progression, treatment failure and treatment discontinuation due to adverse events. Evidence quality was rated as moderate according to GRADE. Further research is likely to have an important impact on results for patients with advanced but non-metastatic prostate cancer treated with non-steroidal antiandrogen monotherapy. However, we believe that research is likely not necessary on non-steroidal antiandrogen monotherapy for men with metastatic prostate cancer. Only high-quality, randomised controlled trials with long-term follow-up should be conducted. If further research is planned to investigate biochemical progression, studies with standardised follow-up schedules using measurements of prostate-specific antigen based on current guidelines should be conducted.

The Evolution and Current Paradigm of Chemotherapy for Metastatic Castrate-Resistant Prostate Cancer

While hormonal manipulation has a pivotal role in the management of advanced prostate cancer, most patients eventually become refractory to such intervention. Until 2004, no treatment had been shown to increase survival in this group of men. Then the demonstration that docetaxel-based chemotherapy improved overall survival, compared with mitoxantrone-based chemotherapy, ushered in a new era of prostate cancer management—and a new treatment pathway. Questions persisted over optimal use of multiple lines of hormone manipulation, and the ideal time in the pathway to offer chemotherapy. The pathway now looks set to change again, as a new generation of treatments emerges from phase III clinical trials. The next challenge facing healthcare professionals in prostate cancer will be to determine the optimal way in which these new agents can be used, in sequence and/or in combination.

Rising prostate-specific antigen after primary treatment of prostate cancer: sequential hormone manipulation

OBJECTIVE

To evaluate systematically the current endocrine treatment options for patients with biochemical recurrence after radical prostatectomy or radiation therapy for localized prostate cancer.

METHODS

Literature search of PubMed documented publications and abstracts from international meetings. Key items included timing and type of salvage hormone therapy, length of its application and handling of side effects.

RESULTS

The majority of patients with isolated prostate-specific antigen (PSA) relapse are not candidates for salvage treatment with curative intent. The PSA threshold that triggers initiation of hormonal therapy is debatable and should be based also on pretreatment risk assessment. Intermittent androgen suppression is an emerging concept to circumvent the unresolved controversy of early versus deferred endocrine therapy. Since the tumor load at time of recurrence is low, peripheral androgen blockade with an antiandrogen and a 5alpha-reductase inhibitor is an acceptable first choice. In case of progression, addition of a LHRH analogue would be the next step. Antiandrogen withdrawal and second-line antiandrogens are clinically of limited value.

CONCLUSIONS

Biochemical-only progression after definitive treatment in curative intent is different from objective or even symptomatic relapse and allows for sequential hormonal therapy with a variety of compounds.

Finasteride and flutamide therapy in patients with advanced prostate cancer: response to subsequent castration and long-term follow-up

OBJECTIVES

To report the efficacy of castration after progression on finasteride and flutamide. Standard androgen deprivation strategies for prostate cancer typically lead to castrate levels of testosterone. One alternative is the use of finasteride and flutamide.

METHODS

A Phase II trial evaluated the combination of finasteride (5 mg/day) and flutamide (250 mg three times daily) in patients with rising prostate-specific antigen levels after local treatment for prostate cancer or with newly discovered metastatic disease. Patients were followed up for subsequent events, including castration-free, androgen-independent prostate cancer (AIPC)-free, and overall survival.

RESULTS

With a median follow-up of 88 months, 5 patients (25%) continued on finasteride and flutamide, and 12 had stopped this combination and subsequently underwent medical or surgical castration. No patients experienced a flutamide withdrawal effect. All patients experienced more than a 50% decline in prostate-specific antigen after castration (mean 89%). The median protocol treatment failure-free survival was 29.9 months, the median castration-free survival was 37 months, and the median AIPC-free survival was 48.6 months. At 5 years, the overall survival rate was 65% (95% confidence interval 47% to 90%); 29% were alive and have not required castration, and 35% were alive and free of AIPC.

CONCLUSIONS

Finasteride and flutamide have a durable effect in suppressing prostate-specific antigen progression in some men with advanced prostate cancer. Furthermore, castration induces secondary responses that may be of shorter duration than if started initially, although the overall period of hormonally responsive prostate cancer is more than 4 years.