Intensity-modulated radiation therapy for prostate cancer: Late morbidity and results on biochemical control

Abstract

Purpose To report on late morbidity and biochemical relapse-free survival (bRFS) after intensity-modulated radiation therapy (IMRT) for prostate cancer. Methods Between 1998 and 2005 133 patients were treated with IMRT for T(1-4) N0 M0 prostate cancer. The median follow-up time was 36 months. In a first cohort, patients received a median planning target volume (PTV) dose of 74 Gy with a hard constraint on maximum rectum dose of 72 Gy (74R72, n = 51). Later, median PTV and maximum rectum dose were increased to 76 and 74 Gy, respectively (76R74; n = 82). We defined low-risk ( n = 20), intermediate-risk ( n = 70) and high-risk ( n = 43) groups. Androgen deprivation was given to patients in the intermediate- and high-risk group. Late gastro-intestinal (GI) and genito-urinary (GU) morbidity and biochemical relapse, in accordance with the ASTRO consensus, were recorded. Results We observed grade 2 GI (17%) and GU (19%), grade 3 GI (1%) and GU (3%) late toxicities. Except for hematuria, the median duration of side-effects was 6 months. Biochemical relapse-free survival (bRFS) at 3 and 5 years was 88% and 83%, respectively, with a significantly better 3-year bRSF for the 76R74 than for the 74R72 group ( p = 0.01). Five-year bRFS for patients in the low-risk, intermediate-risk and high-risk group was 100%, 94% and 74%, respectively ( p < 0.01). Conclusion IMRT for localized or locally advanced prostate cancer combines low morbidity with excellent biochemical control.