Stage III Prostate Cancer Treatment
Evidence (EBRT with or without hormonal therapy):
- Although patients in the RTOG-9413 trial showed a 15% estimated risk of lymph node involvement and received whole-pelvic radiation therapy compared with prostate-only radiation therapy, overall survival (OS) and PSA failure rates were not significantly different.;[Level of evidence: 1iiDiii]
- In a randomized trial, 875 men with locally advanced nonmetastatic prostate cancer (T1b–T2 moderately or poorly differentiated tumors; T3 tumors of any grade) were randomly assigned to receive 3 months of an LH-RH agonist plus long-term flutamide (250 mg orally 3 times a day) with or without EBRT. Nineteen percent of the men had tumor stage T2, and 78% of the men had stage T3.[Level of evidence; 1iiA]
- At 10 years, both overall mortality (29.6% vs. 39.4%; 95% confidence intervaI [CI] for the difference, 0.8%–8.8%) and the prostate cancer-specific mortality (11.9% vs. 23.9%; 95% CI for the difference, 4.9%–19.1%) favored combined hormonal and radiation therapy.
- Although flutamide might not be considered a standard hormonal monotherapy in the setting of T2 or T3 tumors, it is interesting to see that radiation therapy provided a DFS or tumor-specific survival advantage even though this monotherapy was applied. This analysis rests on the assumption that flutamide does not shorten life expectancy and cancer-specific survival. Radiation therapy was not delivered by current standards of dose and technique.
- Another trial compared androgen deprivation therapy (ADT: an LH-RH agonist or orchiectomy) to ADT plus radiation therapy (65–69 Gy to the prostate by 4-field box technique, including 45 Gy to the whole pelvis, seminal vesicles, and external/internal iliac nodes unless the lymph nodes were known to be histologically negative). This trial, (NCIC CGT PR.3/MRC UKPRO7 [NCT00002633]), from the National Cancer Institute of Canada, randomly assigned 1,205 patients with high-risk (PSA >40 ng/ml or PSA >20 ng/ml and Gleason score ≥8), T2 (12%–13% of the patients), T3 (83% of the patients), and T4 (4%–5% of the patients) with clinical or pathologically staged N0, M0 disease.[Level of evidence: 1iiA]
- At a median follow-up of 6 years (maximum = 13 years), OS was superior in the ADT plus radiation therapy group (hazard ratio [HR]death of 0.77; 95% CI, 0.61–0.98, P = .03). OS at 7 years was 74% for the ADT plus radiation therapy group versus 66% for the ADT alone group.
- Although radiation therapy had the expected bowel and urinary side effects, quality of life was the same in each study group by 24 months and beyond.
- The Radiation Therapy Oncology Group (RTOG) performed a prospective, randomized trial (RTOG-8531) in patients with T3, N0, or any T, N1, M0 disease who received prostatic and pelvic radiation therapy and then were randomly assigned to receive immediate adjuvant goserelin or observation with administration of goserelin at time of relapse. In patients assigned to receive adjuvant goserelin, the drug was started during the last week of the radiation therapy course and was continued indefinitely or until signs of progression.[Level of evidence: 1iiA]
- The actuarial 10-year OS rate for the entire population of 945 analyzable patients was 49% on the adjuvant arm versus 39% on the observation arm (P = .002). There was also an improved actuarial 10-year local failure rate (23% vs. 38%, P < .001).
- A similar trial was performed by the European Organization for Research and Treatment of Cancer (EORTC). Patients with T1, T2 (World Health Organization grade 3), N0–NX or T3, T4, N0 disease were randomly assigned to receive either pelvic/prostate radiation therapy or identical radiation therapy and adjuvant goserelin (with cyproterone acetate for 1 month) starting with radiation therapy and continuing for 3 years. The 401 patients available for analysis were followed for a median of 9.1 years.[10,23][Levels of evidence: 1iiA, 1iiDii]
- The Kaplan-Meier estimates of OS at 10 years were 58.1% in the adjuvant goserelin arm and 39.8% in the radiation alone arm (P = .0004). Similarly, 10-year DFS (47.7% vs. 22.7%, P < .0001) and local control (94.0% vs. 76.5%, P < .001) favored the adjuvant arm.[10,23]
- Two smaller studies, with 78 and 91 patients each, have shown similar results.[24,25]
- The role of adjuvant hormonal therapy in patients with locally advanced disease has been analyzed by the Agency for Health Care Policy and Research (AHCPR) (now the Agency for Healthcare Research and Quality). Randomized clinical trial evidence comparing radiation therapy to radiation therapy with prolonged androgen suppression (with an LH-RH agonist or orchiectomy) was evaluated in a meta-analysis. Most patients had more advanced disease, but patients with bulky T2b tumors were included in the study.[Level of evidence: 1iiA]
- The meta-analysis found a difference in 5-year OS in favor of radiation therapy plus continued androgen suppression compared with radiation therapy alone (hazard ratio [HR], 0.631; 95% CI, 0.479–0.831).
- Additionally, the RTOG did a study (RTOG-8610) in patients with bulky local disease (T2b, T2c, T3, or T4), with or without nodal involvement below the common iliac chain: 456 men were randomly assigned to receive either radiation therapy alone or radiation therapy with androgen ablation, which was started 8 weeks before radiation therapy and continued for 16 weeks. This trial assessed only short-term hormonal therapy, not long-term therapy, as the studies analyzed by the AHCPR did.[12,26]
- At 10 years, OS was not statistically significantly different; however, disease-specific mortality (23% vs. 36%) and DFS (11% vs. 3%) favored the combined treatment arm.[Level of evidence: 1iiA]
- A subset analysis of the RTOG-8610 trial and the RTOG-8531 trial that involved 575 patients with T3, N0, M0 disease indicated that long-term hormones compared with short-term hormones resulted in improved biochemical DFS and cause-specific survival.
- This finding was confirmed by RTOG-9202, which reported that radiation therapy plus 28 months of androgen deprivation resulted in longer 10-year disease-specific survival (23% vs. 13%; P < .0001) but not OS (53.9% vs. 51.6%; P = 0.36).
- An unplanned post-hoc–subgroup analysis found increased OS with longer androgen deprivation (28 months vs. 4 months) (45% vs. 32%; P = .0061) in men with high-grade cancers and Gleason scores of 8 through 10.
- Likewise, a meta-analysis of seven randomized controlled trials comparing early hormonal treatment (adjuvant or neoadjuvant) to deferred hormonal treatment (LH-RH agonists and/or antiandrogens) in patients with locally advanced prostate cancer, whether treated by prostatectomy, radiation therapy, or watchful waiting or active surveillance, showed improved overall mortality for patients receiving early treatment (relative risk, 0.86; 95% CI, 0.82–0.91).[Level of evidence: 1iiA]
- The duration of neoadjuvant hormonal therapy has been tested in a randomized trial (TROG 96.01 [ACTRN12607000237482]) involving 818 men with locally advanced (T2b, T2c, T3, and T4) nonmetastatic cancer treated with radiation therapy (i.e., 66 Gy in 2 Gy daily fractions to the prostate and seminal vesicles but not including regional lymph nodes). In an open-label design, patients were randomly assigned to radiation therapy alone, 3 months of neoadjuvant androgen deprivation therapy (NADT) (goserelin 3.6 mg subcutaneously each month plus flutamide 250 mg by mouth 3 times per day) for 2 months prior to and during radiation, or 6 months of NADT for 5 months prior to and during radiation.[Level of evidence: 1iiA]
- After a median follow-up of 10.6 years, there were no statistically significant differences between the radiation alone group and the radiation plus 3 months of NADT group.
- However, the 6-month NADT arm showed better prostate cancer-specific mortality and overall mortality than radiation alone; 10-year all-cause mortality 29.2% versus 42.5% (HR, 0.63; 95% CI, 0.48–0.83, P = .0008).