The Impact of Sequence of Bimodality Approach on Low-Risk Prostate Cancer Outcomes

Abstract

Purpose/Objective(s): To report early and late toxicity and biochemical outcome in a prospective series of 445 patients with intermediateor highrisk clinically localized prostate cancer treated with either HD-3D-CRT or with LD-3D-CRT+HDR-B. Materials/Methods: Between 12/1999 and 10/2005, 445 patients (pts) with PSA’10, Gleason score’6 and/or T2b-T3 N0 M0 prostate cancer entered the study. Pts were prospectively 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), limiting the maximum rectal dose to 85% of the prescribed dose. 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 or more rectal toxicity. Twenty-eight pts of group 1 (12.5%) and 6 pts of group 2 (2.7%) developed grade 2 rectal toxicity (rectal bleeding or urgency). Fifteen pts in group 1 (6.7%) and 3 pts in group 2 (1.3%) developed grade 1 rectal bleeding (less than 2 times/week). With a mean follow-up of 84 months, the 8-year free-from-failure survival was 90.7% and 98.3% (p < 0.02) in group 1 and 2 respectively; free-frommetastases survival 96.9% and 97.9% (p < 0.08)for group 1 and 2 respectively; and cause-specific survival 97.4% and 98.3% (p < 0.09). Conclusions: High-dose 3D-EBRT + HDR brachytherapy was a safe and effective method of escalating the dose to the prostate without increasing the risk of late effects. Acute as well as late rectal complications were significantly reduced with the combined treatment, compared with what was observed with high-dose conventional, 3D-conformal radiation therapy. Control rates were better with in the HDR-boosted patients as expected by higher effective-dose. Author Disclosure: B. Guix: None. J. Bartrina: None. J. Tello: None. I. Henriquez: None. L. Quinzanos: None. T. Lacorte: None. I. Guix: None. G. Galdon: None. M. Espino: None. M. Espino: None.