Planned organ preservation for selected T2-3 rectal cancer: French experience using chemoradiotherapy and contact xray boost.

Abstract

751 Background: The Lyon R96-02 randomized trial has demonstrated in T2-3 rectal cancer that external beam radiotherapy (EBRT) with Contact X Ray brachytherapy (CXB) boost was increasing clinical complete response, sphincter preservation and in early cases organ preservation. We report French experience in 3 radiotherapy departments using CXB boost with chemoradiotherapy (CRT) in early T2T3N0. Methods: Selection based on digital rectal examination, colonoscopy, MRI (and/or Endorectal-ultrasound). Inclusion : adenocarcinoma (distal, middle rectum), T2 T3a-b, tumor diameter ≤ 4cm, N0, M0. Treatment : CXB (80-110 Gy/3-4 fr) followed by CRT (CAP 50). Tumor response assess on week 14 : DRE, rigid rectoscopy and MRI. Clinical complete response (cCR) defined as no visible tumor, supple rectal wall and TRG 1-2 on MRI. In case of cCR a close surveillance or local excision was proposed. Results: Between 2002 -2016, 84 patients treated. Median age: 75 years, Male: 59, Female: 25. Operable patients: 69 (83%). T2 : 52, T3 : 32 (Lyon Villeurbanne : 16, Macon : 11, Nice : 57). Median follow-up time : 53 months. cCR was achieved in 94% of cases. Local excision performed in 17 patients (ypT0 : 16). At 4 years, the cancer specific survival was 82% [CI:96-70] and the local relapse rate 12% [CI: 2-22]. No isolated perirectal lymph node relapse observed. After 4 years, 3 more local relapses observed (4, 6, 7 years). Main late toxicity ( > 6 months after treatment) was rectal bleeding (radiation telangiectasia) which required plasma argon coagulation in 5 patients. No TME surgery was performed and organ preservation was achieved in all cases. Bowel function was good in 85% of patients (LARS score < 20). Conclusions: When combining CXB with CRT, rectal cancer T2T3a-b N0 ≤4cm achieve a high rate of cCR (≥85%) with organ preservation, good bowel function, low rate of local relapse ( < 15%) and low toxicity. As rectal adenocarcinoma is radioresistant, the treatment must use a CXB boost. Like anal squamous cell cancer, planned organ preservation can be proposed to operable patients. The ongoing European OPERA trial aims at bringing evidence to this option.