Surgery is the standard treatment for cT2-3 rectal cancers [1]. However, after low anterior resection (LAR), quality of life is often affected [2]. Habr-Gama has demonstrated that when clinical complete response (cCR) is achieved after neoadjuvant chemoradiotherapy (nCRT), a watch-and-wait policy can preserve the rectum [3]. This approach is attracting growing interest, and most series report a cCR and local recurrence rates close to 40% and 25%, respectively [4,5]. These suboptimal data are explained by the relative radioresistance of rectal adenocarcinoma, a dose above 90 Gy being necessary to sterilise only 50% of T3 tumors [6,7]. Endoluminal radiation dose escalation is a strategy to increase the cCR rate [8,9]. Contact X-ray brachytherapy (CXB) was pioneered in the 1970s by Papillon [10] and was used in Europe and the US [11]. The Lyon R 96-02 randomised trial proved that when compared with neoadjuvant external beam radiotherapy (EBRT) alone, a CXB boost combined with EBRT was able to increase cCR and sphincter preservation rates [12,13]. In 2009, a renaissance of CXB was made possible with the design of a new CXB Papillon 50 TM system [14]. In France, three institutions are performing CXB following the Lyon principles with two main end-points: clinical response and local recurrence, which are key parameters for organ preservation. We report their results in selected cT2-3 tumours.

Between 2002 and 2016, 74 consecutive patients were treated in three French institutions (Lyon-Villeurbanne, Maˆcon, Nice) with organ preservation intent by radiation oncologists with long experience of CXB treatments (J.D., J.-P.G., K.B., N.B., and R.C.). This is a retrospective analysis of a prospective cohort. Patients were selected based on the following: with adenocarcinoma; accessible to digital rectal examination (DRE); T2, T3, N0-1 and M0 (UICC tumour-node-metastasis 7th classification); tumour diameter < 5 cm; less than half rectal circumference extension and no infiltration of the anal canal. Only N1 tumours with node < 1 cm were included. Workup was always performed with a DRE and rigid rectoscopy in the knee-chest position, by colonoscopy, endorectal ultrasound (ERUS) and/or magnetic resonance imaging (MRI), thoracoabdominopelvic computed tomography (CT) scan (and/ or positron-emission tomography [PET]-CT scan), routine serum biology and carcino-embryonic antigen (CEA) serum level tests. The performance status and operability were assessed. Half of the patients were referred by surgeons, and high surgical risk was often an argument to propose the option of non-radical surgery approach which explains a high mean age of this cohort. All patients gave informed consent for this conservative treatment after a multidisciplinary team (MDT) discussion.