Dose escalation by high-dose 3D-conformal radiotherapy (HD-3D-CRT) or low-dose 3D-conformal radiotherapy plus HDR brachytherapy (LD-3D-CRT+HDR-B) for intermediate- or high-risk prostate cancer: Early results of a prospective comparative trial

Abstract

5118 Background: To report early and late toxicity and preliminary biochemical outcome in 445 patients with intermediate- or high-risk clinically localized prostate cancer treated with either HD-3D-CRT or with LD-3D-CRT+HDR-B. Methods: Between December 1999 and October 2005, 445 patients (pts) with PSA'10, Gleason score'6 and/or T2b-T3 N0 M0 prostate cancer entered the study. Pts were assigned to one of the two treatment groups: 76 Gy HD-3D-CRT to the prostate in 38 fractions (group 1; 223 patients) or 46 Gy LD-3D-CRT+ 16 Gy HDR-B given in 2 fractions of 8 Gy (group 2, 222 patients). Both groups were well balanced taking into account patient's as well as tumors’ characteristics. Toxicities were scored by the EORTC /RTOG morbidity grading scales. Special attention to local, regional or distant recurrence, survival, late effects, PSA and testosterone levels and quality of life was done. Results: All pts completed treatment. None pts included in the group 1 or 2 experienced grade 3 rectal toxicity. 28 pts of group 1 (12.5%) and 6 pts of group 2 (2.7%) developed grade 2 rectal toxicity (rectal bleeding or urgency). 15 pts in group 1 (6.7%) and 3 pts in group 2 (1.3%) developed grade 1 rectal bleeding (less than 2 times/week). In group 1 and 2, 81.8%and 95,9% of pts were free from rectal reactions respectively (p < 0.005). 19 pts in each group developed acute Grade 2 urinary symptoms (mainly dysuria), and none experienced urinary retention. No pts (0%) developed Grade 3 or 4 rectal or urinary complications. With a mean follow-up of 55 months, the 5-year actuarial PSA relapse-free survival rates for intermediate- and high-risk group 1 pts were 92 and 91 % respectively and 97 and 96 % for group 2 pts (p < 0.06). Conclusions: High-dose 3D-EBRT +HDR brachytherapy is a safe and effective method of escalating the dose to the prostate without increasing the risk of late effects. Acute and late rectal and urinary complications were significantly reduced with the combined treatment, compared with what was observed with high-dose conventional, 3D-CRT. Short-term PSA control rates tends to be better with in the HDR-boosted patients as spected by higher effective-dose. No significant financial relationships to disclose.