Late complications after proctectomy in rectal cancer patients who underwent radiotherapy

Radiotherapy for advanced rectal cancer is an important treatment to reduce local recurrence.

The purpose of this study was to identify the late structural changes of pelvis and adverse effects after radiotherapy for rectal cancer.

Between January 2000 and December 2009, we performed a single-center case-control study with 687 patients who underwent curative treatments for rectal cancer. A radiotherapy group (RTX) and a non-radiotherapy group (NRTX) were compared. Of the 687 patients, 207 cases in the RTX group were identified, and 207 controls for the NRTX group were selected for analysis. Each case had one control matched for age (±5 y), sex, tumor location, and operation type. All instances of radiotherapy were performed as long-course treatment methods (45.0-50.4 Gy) with concurrent 5-fluorouracil (5-FU)-based chemotherapy. Late complications were usually assessed as structural changes of the pelvic organ based on physical examination or radiologic or endoscopic findings 6 months after the rectal resection or pelvic radiation.

In terms of overall complications, the RTX group (N = 45, 21.7 %) experienced more frequent complications than the NRTX group (N = 25, 12.1 %, p = 0.009). In particular, anastomosis-related complications were more common in the RTX group (9.2 %) than in the NRTX group (2.4 %, p = 0.003). Successful treatment after late complications in the RTX group (33.3 %) was less likely than in the NRTX group (70.0 %, p = 0.010). Late complications in the RTX group gradually increased with time (11.6 % at 2 y, 17.9 % at 3 y, 19.8 % at 4 y) at a higher rate than in the NRTX group (6.8 % at 2 y, 10.6 % at 3 y, 10.6 % at 4 y, p = 0.009).

Radiotherapy for rectal cancer patients may induce late pelvic complications as time progresses, and irreversible tissue changes due to radiation could disrupt the successful treatment of radiation-related complications.