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

751Background: 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,...