Dearnaley DP et al. (2007) Escalated-dose versus standard-dose conformal radiotherapy in prostate cancer: first results from the MRC RT01 randomised controlled trial. Lancet Oncol 8: 475–487

Conformal radiotherapy (CRT) enables precise delivery of radiotherapy to tumors. In localized prostate cancer, CRT could increase efficacy by enabling delivery of a higher dose of radiation than that permitted by conventional radiotherapy techniques, but there have been fears of consequent increases in long-term toxicity. An analysis of data from the Medical Research Council RT01 trial shows that dose-escalated CRT with neoadjuvant androgen suppression provides considerably better prostate tumor control than does standard-dose CRT, but with a slightly higher risk of long-term adverse events.

Men (median age 67 years) with histologically confirmed localized prostate cancer and prostate-specific-antigen concentrations of <50 ng/ml (median 12.8 ng/ml) were placed on neoadjuvant androgen suppression therapy for 3–6 months before initiation of CRT, and throughout radiotherapy. Patients were randomly assigned to receive CRT of either 64 Gy in 32 fractions (standard-dose group; n = 421) or 74 Gy in 37 fractions (dose-escalated group; n = 401).

The 5-year biochemical progression-free survival rate was significantly higher for the dose-escalated group than for the standard-dose group (71% vs 60%; P = 0.0007), independent of risk of recurrence or seminal vesicle involvement. Local control and metastasis-free survival rates were higher in the dose-escalated group (hazard ratios 0.65 and 0.74, respectively). Furthermore, the need for salvage androgen suppression was lower in these patients. There were, however, nonsignificant increases in the risks of bowel dysfunction, late gastrointestinal toxicity and late genitourinary toxicity at 5 years in the dose-escalated group (hazard ratios 1.34, 1.05 and 1.36, respectively).