Total neoadjuvant treatment versus standard chemoradiation to increase the sphincter preservation rate for distal locally advanced rectal cancer (TESS)

TPS3615 Background: Standard treatment of rectal cancer is neoadjuvant capecitabine chemotherapy with radiotherapy, followed by total mesorectal excision (TME). Total neoadjuvant treatment (TNT), a new concept, suggests organ preservation as an alternative to rectal excision in good responders after neoadjuvant chemoradiotherapy to decrease surgical morbidity and increase quality of life. RAPIDO and PRODIGE-23 trials showed that TNT strategy could improve the pathological complete response (pCR) rateand reduce the risk of distant metastasis. The objective of this trial is to increase the proportion of sphincter preservation rate for distal rectal cancer patients by optimizing tumor response, by using TNT regimen as compared to conventional chemoradiotherapy. TESS (clinicalTrials.gov, NCT03840239), a prospective, open label, multicenter, randomized phase 2 study, is underway. Methods: Main inclusion criteria include: cT3-4aNany or cTanyN+ rectal adenocarcinoma aged 18-70y; ECOG performance 0-1; distance≤5cm from anal verge. 168 patients will be randomized 1:1. Patients in the TNT group will receive 2 cycles of neoadjuvant chemotherapy Capeox (capecitabine + oxaliplation) before, during and after radiotherapy 50Gy/25 fractions, before TME (or other treatment decisions, such as watch and wait) and adjuvant chemotherapy capecitabine 2 cycles. Patients in the standard treatment group will receive neoadjuvant radiotherapy 50Gy/25 fractions combined with capecitabine 5 weeks before TME (or other treatment decisions, such as watch and wait), and adjuvant chemotherapy Capeox 6 cycles. Primary endpoint is the rate of sphincter preservation rate (absence of stoma). Secondary endpoints include: Ratio of sphincter preservation strategy; pathological complete response rate and tumor regression grade distribution; acute toxicity; surgical complications; long-term anal function; late toxicity; ECOG standard score; disease-free survival; overall survival. First site opened in January 24, 2019. Clinical trial information: NCT03840239.