Administering radiotherapy immediately after prostatectomy helped nearly two-thirds of users in a recent study remain free of prostate cancer after 10 years, compared with just over one-third of study participants who remained disease-free after prostatectomy not followed by radiotherapy.

These findings emerged from the 10-year follow-up results of the European Organisation for Research and Treatment of Cancer (EORTC) trial 22911, which involved 1,005 men aged 75 years or younger who began the study with untreated, high-risk prostate cancer. A research team led by Michel Bolla, MD, of the Department of Radiation Oncology at the Centre Hospitalier Universitaire A Michallon in Grenoble, France, had randomized 503 of the men to watchful waiting until first signs of disease recurrence after prostatectomy and 502 to postoperative irradiation (60 Gy of conventional irradiation given for 6 weeks within 4 months of surgery). All the men were then followed for a median of 10.6 years (range 2 months to 16.6 years).

As the investigators reported in The Lancet, postoperative radiotherapy significantly improved biochemical progression-free survival (PFS) compared with the monitoring approach, with 39.4% (198) of the radiation patients and 61.8% (311) of the others experiencing biochemical or clinical progression or death during follow-up. These findings supported the initial results, recorded 5 years into the study. However, improvements in clinical PFS were not maintained: After 10 years, clinical PFS was not significantly improved with immediate radiotherapy, and radiotherapy had no effect on the 10-year rates of metastasis or overall survival.

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Late adverse effects of any type or any grade were more frequent in the postoperative radiotherapy group, with a 10-year cumulative incidence of 70.8%, compared with 59.7% in the wait-and-see group. No significant difference in severe toxicity existed between the groups. The men who underwent radiation also had substantially better local disease control, rendering them less likely to need hormonal therapy, the prolonged use of which can lead to side effects.