Introduction

The risk of complications after radiation therapy (RT) is still controversial. Therefore, we aimed at reporting early and late genito-urinary (GU) and gastro-intestinal (GI) toxicity of post-prostatectomy RT using a large multi-institutional series.

Methods

The study included 1196 patients treated at six tertiary referral centres with either: (i) adjuvant RT (aRT); (ii) salvage RT (sRT); (iii) RT for PSA persistence (pRT), delivered at PSA level ≥0.1 ng/ml within 6 months after RP. The irradiation of the pelvic lymph nodes area was left at the discretion of the treating physician. Acute and late radio-induced GU and GI complications were classified according to the RTOG/EORTC scoring system. Multivariable logistic regression analysis was used to predict the risk of grade ≥2 early and late GU and GI toxicity. Covariates consisted of: radiation dose, radiation field (prostatic bed vs. whole pelvis), time from RP to RT, concomitant hormonal therapy (HT), and number of lymph nodes removed during RP.

Results

Overall, 281 (23%), 729 (61%), and 186 (16%) patients received aRT, sRT, and pRT, respectively. Median follow-up was 72 months. Overall, 658 (55%) patients had an early GU complication, of which 170 (14%) and 11 (1%) were grade 2 and 3, respectively. Similarly, 796 (67%) had an early GI complication, of which 287 (24%) and 3 (0.3%) were grade 2 and 3, respectively. Late GU complications were observed in 449 (38%) patients, of whom 140 (12%) and 72 (6%) had grade 2 and 3 events, respectively. Similarly, late GI complications were observed in 362 (30%) patients, of whom 120 (12%) and 19 (1%) had grade 2 and 3 events, respectively. At multivariable analysis, the concomitant HT administration was the only predictor that was significantly associated with both GU and GI early (OR: 2.03, p=0.002; and OR: 1.54, p=0.037) and late complications (OR: 2.08, p<0.001; and OR: 1.52, p=0.01). Whole pelvis irradiation was a significant predictor only for early GU (OR: 1.77; p=0.006) and early GI complications (OR: 3.20; p<0.001). Finally, the number of lymph nodes removed was associated with both early and late GI complications (OR: 1.12, p=0.02; and OR: 1.18, p=0.01).

Conclusions

At long-term follow-up, the risk of complications is not negligible, despite being mostly low grade. Concomitant HT represents a significant predictor of both early and late high-grade complications. Whole pelvis irradiation is a significant risk factor for early high-grade complications, whereas number of nodes removed is significantly associated with late high-grade complications

Funding

none