Intermediate neoadjuvant radiotherapy for T3 low/middle rectal cancer: postoperative outcomes of a non-controlled clinical trial.

Background: The benefits of adjuvant radiotherapy in rectal carcinoma are well known. However, there is still considerable uncertainty about the optimal radiation treatment. There is an ongoing debate about the choice between very short treatments immediately followed by surgical resection and prolonged treatments with delayed surgery. In this paper, we describe an interim analysis of a non-controlled clinical trial in which radiotherapy delivered with intermediate dose/duration was followed by surgery after about 2 weeks to improve local control and survival after curative radiosurgery for cT3 low/middle rectal cancer.

Methods: Preoperative radiotherapy (36 Gy in 3 weeks) was delivered in 248 consecutive patients with cT3NxM0 rectal adenocarcinoma within 10 cm from the anal verge, followed by surgery within the third week after treatment completion.

Results: 166 patients (66.94%) underwent anterior resection, 80 patients (32.26%) the Miles' procedure and 2 patients (0.8%) the Hartmann's procedure. Local resectability rate was 99.6%, with 226 curative-intent resections. The overall rate of complications was 27.4%. 5-year oncologic outcomes were evaluated on 223 patients. The median follow-up time was 8.9 years (range 5-17.4 years); local recurrence (LR) rate and distal recurrence (DR) rate after 5 years were 6.28% and 21.97%, respectively. Overall survival was 74.2%; disease free survival was 73.5%; local control was 93.4 % and metastasis-free survival was 82.1%.

Conclusions: preoperative radiotherapy with intermediate dose/duration and interval between radiotherapy and surgery achieves high local control in patients with cT3NxM0 rectal cancer, and high DR rate seems to be the major limitation to improved survival.