Escalated-dose radiotherapy did not increase survival in prostate cancer

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1: Escalated-dose conformal radiotherapy with neoadjuvant androgen deprivation did not increase long-term, overall survival for patients with prostate cancer.

2: The escalated-dose regimen did result in prolonged biochemical progression-free survival, although with increased toxicity. 

Evidence Rating: 1 (Excellent)

Study Rundown: This study randomized men with T1b-T3a,N0,M0 prostate cancer with PSA levels <50ng/mL to neoadjuvant androgen deprivation therapy (ADT) plus either high dose (74 Gray over 37 treatments) or low dose (64 Gy over 32 treatments).  The co-primary end points were overall survival, defined as time from randomization to death due to any cause, and biochemical survival, defined as time from randomization to death attributable to prostate cancer or development of metastatic disease, whichever happened first.  The authors found that at 10 years, overall survival was identically 71% in both groups.  However, biochemical progression-free survival was 55% in the high dose group as compared to 43% in the control group.  This study also showed that high dose radiotherapy delays salvage ADT, a treatment that produces unwanted andropausal side-effects.  However, this advantage must be balanced with a well characterized dose-dependent increase in bowel-related adverse effects.  A limitation of this study was that side effect data was only collected for 5 of the 10 years analyzed, which severely limited the cost-benefit analysis of the escalated-dose regimen.  Furthermore, the applicability of results from this trial is constrained given recent technological advances in radiation therapy.

Click to read the story in the Lancet Oncology

Relevant reading: Radiotherapy and Short-Term Androgen Deprivation for Localized Prostate Cancer

In-Depth [phase 3, open-label, randomized controlled trial]: This study was a phase 3, open-label, randomized controlled trial.  The escalated-dose group consisted of 422 men while the control group had 421.  At ten years follow-up, overall survival was 71% in the high-dose group compared to 71% in the low dose group (hazard ratio 0.99, 95% CI 0.77-1.28, p=0.96).  Biochemical progression-free survival at ten years was 55% for the high dose group compared to 43% for the control-dose group (HR 0.69, 95% CI 0.56-0.84, p=0.0003).  Analyses were done on an intention to treat basis and hazard ratios were estimated with Cox regression.

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