Dose escalation with 3D-CRT in prostate cancer: French study of dose escalation with conformal 3D radiotherapy in prostate cancer - Preliminary results

Purpose: To evaluate the feasibility of dose escalation in a multi-institut ional study in prostate cancer patients. Methods and Materials: Between October 1995 and October 1998, 164 patients with localized adenocarcinoma of the prostate were treated with 3-dimension al conformal radiotherapy at one of five French institutions. The dose of r adiation was escalated from 66 to 80 Gy (ICRU point). The maximum dose to t he rectal wall was limited to 75 Gy. Results: Results were compared in two groups, one (group 1) receiving the s tandard dose (n = 46 patients; 66 to 70 Gy) and the other (group 2) receivi ng the escalated dose (n = 118 patients; 74 to 80 Gy). There was no differe nce in the characteristics of patients between the two groups. The mean fol low-up time was 32 months in group 1 and 17.5 months in group 2. No statist ical difference between the two groups was observed in the incidence of lat e gastrointestinal and urinary toxicities. The probability of achieving a p osttreatment prostate-specific antigen nadir of less than or equal to 1 ng/ mL in the 120 patients who did not receive neoadjuvant androgen-deprivation therapy was significantly higher in the dose-escalation group and was dire ctly related to the dose of radiation given. Conclusion: This multi-institutional study demonstrated the feasibility of escalating the dose of radiation to 80 Gy in prostate cancer patients. (C) 2000 Elsevier Science Inc.