Higher Radiation Dose Aids Prostate Cancer Patients

The study was reported in the August 2002 issue of the International Journal of Radiation Oncology, Biology, and Physics, the journal of the American Society for Therapeutic Radiology and Oncology.

In the study, researchers analyzed data from a radiotherapy-dose-escalation trial undertaken between 1993 and 1998. The results at the 60-month follow-up found that intermediate-to-high risk patients benefited from an 8 Gy dose increase but also suffered more side effects than earlier analysis revealed. The study involved 301 stage T1-T3 patients, whose distribution by randomization arm and stage, Gleason score, and pretreatment prostate-specific antigen (PSA) level was even. The primary end point was freedom from failure (FFF), including biochemical failure, defined as three rises in PSA level.

The FFF rate for the 70 and 78 Gy arms at six years was 64% and 70%, respectively. Dose escalation to 78Gy most helped men with a pretreatment PSA greater than 10 ng/ml. In these patients, the FFF rate was 62% for the 78 Gy arm versus 43% for those who received 70 Gy. No significant dose response was found for patients with a pretreatment of PSA of less than 10 ng/ml. More side effects were found in the 78 Gy group. The grade 2 or higher toxicity rate at six years was 26% for the 78 Gy arm and 12% for the 70 Gy arm. Grade2 or higher bladder complications were similar at 10%.

"It is now clear that patients at intermediate-to-high risk should be targeted for dose escalation,” said Alan Pollack, M.D., Ph.D., chairman of radiation oncology at Fox Chase Cancer Center (Philadelphia, PA, USA) and lead author of the study. Dr. Pollack notes that radiation therapy techniques used in the trial several years ago are antiquated compared to methods in use today. He says using conformal or IMRT techniques from the beginning of treatment and minimizing exposure of the bladder and rectum should dramatically reduce side effects.





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Fox Chase Cancer Center