Local Excision for organ preservation in early REctal cancer with No Adjuvant treatment (LORENA Trial): prospective observational study protocol

[Display omitted] Local resection (LR) is an alternative to total mesorectal excision (TME) that avoids its associated morbidity to the detriment of oncological radicality in early stages of rectal cancer. There are several conditioning factors for the success of this strategy, such as poor prognosis histological factors (PPHF), involvement of resection margins, clinical under staging, or complications that may lead to the indication for radical surgery with TME. An international multicenter prospective observational open-label study has been designed. Consecutive patients diagnosed with early rectal cancer (cT1N0 on MRI +/− endorectal ultrasound) whose lower limit is a maximum of 2 cm proximal to the ano-rectal junction will be included. The primary objective of the study is to determine the overall prevalence of PPHF after LR and requiring TME or postoperative radio-chemotherapy. The prevalence of PPHF conditioning the success of LR in early distal rectal cancer has been scarcely studied in the literature, and there are very few prospective data. Considering the increasing interest in the watch and wait strategy in rectal cancer and its possible application in early-stage tumors, it seems necessary to know this information. The results of this study will help guide clinical practice in patients with early distal rectal cancer. It will also provide quality information for the design of future comparative studies to improve organ preservation success in these patients. Trial registration number: NCT05927584. La resección local (RL) es una alternativa a la exéresis mesorrectal total (EMT) que permite evitar su morbilidad asociada en detrimento de la radicalidad oncológica en estadios precoces de cáncer de recto. Existen diversos condicionantes para el éxito de esta estrategia, como factores histológicos de mal pronóstico (FHMP), afección de márgenes de resección, infra-estadificación clínica, o complicaciones que pueden conllevar la indicación de cirugía radical con EMT. Se ha diseñado un estudio multicéntrico internacional observacional prospectivo en régimen abierto. Se incluirán pacientes consecutivos diagnosticados de cáncer de recto precoz (cT1N0 en RMN +/− ecografía endorrectal) cuyo límite inferior esté a un máximo de 2 cm proximal a la unión ano-rectal. El objetivo primario del estudio es determinar la prevalencia global de FHMP tras RL y que obligan a EMT o realización de radio-quimioterapia postoperatoria. La prevalencia de FHMP como factor limita