Dose escalation using contact X-ray brachytherapy (Papillon) for rectal cancer: does it improve the chance of organ preservation?

OBJECTIVE: A watch and wait policy for patients with a clinical complete response (cCR) after external beam chemoradiotherapy (EBCRT) for rectal cancer is an attractive option. However, approximately one-third of tumours will regrow, which requires surgical salvage for cure. We assessed whether contact X-ray brachytherapy (CXB) can improve organ preservation by avoiding surgery for local regrowth. METHODS: From our institutional database, we identified 200 of 573 patients treated by CXB from 2003 to 2012. Median age was 74 years (range 32-94), and 134 (67%) patients were males. Histology was confirmed in all patients and was staged using CT scan, MRI or endorectal ultrasound. All patients received combined CXB and EBCRT, except 17 (8.5%) who had CXB alone. RESULTS: Initial cCR was achieved in 144/200 (72%) patients. 38/56 (68%) patients who had residual tumour received immediate salvage surgery. 16/144 (11%) patients developed local relapse after cCR, and 124/144 (86%) maintained cCR. At median follow up of 2.7 years, 161 (80.5%) patients were free of cancer. The main late toxicity was bleeding (28%). Organ preservation was achieved in 124/200 (62%) patients. CONCLUSION: Our data suggest that CXB can reduce local regrowth to 11% compared with around 30% after EBCRT alone. Organ preservation of 62% achieved was higher than reported in most published watch and wait studies. Advances in knowledge: CXB is a promising treatment option to avoid salvage surgery for local regrowth, which can improve the chance of organ preservation in patients who are not suitable for or refuse surgery.