[Multicenter study on dose escalation with conformal and conventional radiotherapy for the treatment of localized prostatic cancer. Preliminary results of tolerance and quality of life].

Objective: To study the safety of conformal radiotherapy dose escalation up to 80 Gy for curative treatment of prostate cancer.

Material And Methods: A multicentre trial sponsored by the PHRC include 164 patients under the age of 75 years with stage T1b-T3 N0 M0 prostatic adenocarcinoma, between 1995 and 1998. The prostate was treated at 5 dose levels: 18 patients at 66 Gy, 28 at 70 Gy, 49 at 74 Gy, 48 at 78 Gy, 21 at 80 Gy. The acute and delayed toxicity was graded according to a multidisciplinary glossary. Quality of life was evaluated before and one year after treatment using the EORTC QLQ-C30 questionnaire and additional questions.

Results: 89% and 55% of mild or moderate gastrointestinal and urinary adverse effects were observed during treatment, respectively. At long-term follow-up, of the 162 evaluable patients, 12.3% presented grade 2 adverse effects and 2.5% presented grade 3 adverse effects (1 case of haematuria, 2 urethral strictures, 1 bladder neck lesion) with no significant difference between the various dose levels. Two successive quality of life questionnaires were available for 119 patients: tiredness, pain and dyspnoea increased in parallel, but non-significantly in the groups receiving conventional doses or high doses. The proportion of patients reporting sexual activity without endocrine therapy decreased from 48% before treatment to 35% one year later. The proportion of patients with no clinical or laboratory signs of progression was higher in the high-dose group.

Conclusion: No significant difference was observed between conventional dose levels and high dose levels in terms of toxicity or quality of life. As the adverse effects were acceptable, a randomized trial comparing 70 Gy and 80 Gy has been initiated.