Total Neoadjuvant Chemotherapy in Rectal Cancer: Current Facts and Future Strategies

Abstract

Despite preoperative chemoradiotherapy (CRT) and total mesorectal excision improving the local control for locally advanced rectal cancer (LARC), oncologic outcomes and survival were not significantly improved because the main prognostic factor is distant metastasis. Thus, total neoadjuvant chemotherapy (TNT) as a novel approach has been proposed to improve chemotolerance. Since the first randomized phase II trial of TNT versus standard CRT demonstrated in 2012, many prospective and retrospective studies have been published. The initial consensus from TNT studies was that pathological complete response, pathological response of the main tumor, and local control are more favorable at TNT than at CRT. Furthermore, recent studies such as the PAPIDO trial and PRODIGE 23 trial made a major breakthrough of the treatment of TNT, showing that TNT improves the disease-free survival compared to standard treatment with longcourse CRT. In addition, several innovative findings of TNT were clarified by prospective phase II trial. In this review, we summarize the most recent advances in TNT based on the findings of pivotal clinical trials for patients with LARC.