Immediate postoperative radiation improves prostate cancer progression survival

By Liam Davenport, medwireNews Reporter

Radiation immediately after prostate cancer surgery substantially improves biochemical progression-free survival and local control over 10 years compared with a wait-and-see policy, European study findings indicate.

Lead researcher Michel Bolla, from the Centre Hospitalier Universitaire A Michallon, in Grenoble, France, commented in a press release: "These long-term results reassure us of the continued benefit and safety of radiation therapy after prostatectomy for a large proportion of men with locally advanced or high-risk prostate cancer.

"They also suggest that younger patients and those with positive surgical margins are most likely to benefit from immediate radiotherapy, whereas in older adults (aged 70 years plus) it could have detrimental effects."

The team randomly assigned 1005 patients aged 75 years or younger with untreated cT0-3 prostate cancer to receive 60 Gy postoperative irradiation to the surgical bed over 6 weeks or to receive a wait-and-see policy until biochemical progression. This was defined as a prostate-specific antigen increase greater than 0.2 µg/L confirmed twice at least 2 weeks apart.

The patients were followed up for a median of 10.6 years. There were no instances of grade 4 toxicity. The 10-year cumulative incidence of severe, grade 3 toxicity after postoperative radiation was higher in the immediate radiation group than in the wait-and-see group, at 5.3% versus 2.5%. Grade 2 or higher genitourinary toxicity was also higher in the immediate radiation group, at 21.3% versus 13.5% in the wait-and-see group, although grade 2 or higher gastrointestinal toxicity was similar, at 2.5% and 1.9%.

The researchers also report in The Lancet that late adverse effects were significantly more common in the immediate postoperative radiation group than in the wait-and-see group, at 70.8% versus 59.7%.

However, biochemical progression or clinical progression or death was significantly less common in the postoperative radiation group than in the wait-and-see group, at 39.4% versus 61.8% and a hazard ratio of 0.49. Cumulative biochemical progression-free survival at 10 years was 60.6% with postoperative radiation versus 41.1% for the wait-and-see group, again a significant difference.

The proportion of patients who underwent active salvage treatment was 21.8% and 47.5% in the postoperative radiation and wait-and-see groups, respectively, with initiation at a median of 4.2 years and 2.9 years after study entry, respectively.

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