1.Evidence-based application of neoadjuvant immunotherapy in locally advanced rectal cancer
Pu WENJI ; Su XIAOYE ; Feng LINGLING ; Chen WENQI ; Xu ZHIYUAN ; Jin JING
Chinese Journal of Clinical Oncology 2024;51(9):472-479
Deficient mismatch repair(dMMR)is currently recognized as a biomarker for predicting the efficacy of immune checkpoint inhib-itors(ICIs),and domestic and foreign guidelines recommend first-line immunotherapy for patients with solid dMMR tumors.For rectal can-cer,only 5%of patients are classified as dMMR/microsatellite instability-high(MSI-H),and most have"immune desert type"or mismatch re-pair proficient(pMMR)/microsatellite stabilization(MSS)diseases,which respond poorly to ICIs.Therefore,recently,the synergistic effect of immune drugs and neoadjuvant chemoradiotherapy has been the focus of basic and clinical research.An increasing number of clinical trials of phase Ⅱ/Ⅲ immuno-total neoadjuvant therapy(iTNT)have emerged,and the management of locally advanced rectal cancer(LARC)has begun to enter the non-operative treatment era.Furthermore,an increasing number of studies support the efficacy of neoadjuvant immun-otherapy in patients with dMMR/MSI-H LARC,which exempts such patients from surgery and chemoradiotherapy as follow-up treatment and results in a pivot in the treatment paradigm of a watch-and-wait strategy.Regarding the LARC with pMMR/MSS,the preliminary iTNT findings support ICIs as a shift from an initial posterior-line palliative scheme to a first-line selection strategy and the continuation of large-scale clinical trials.However,no definitive conclusion has been reached regarding the best iTNT application for LARC.Recent studies have shown that short-course radiotherapy and sequential neoadjuvant chemotherapy,combined with immunotherapy,can achieve good short-term outcomes.Finally,identifying other new biomarkers may facilitate the identification of patients with pMMR/MSS who are sensitive to immune drugs(especially for low rectal cancer).In the future,the treatment strategy of LARC should be combined with the stratification of clinical recurrence risk and patient willingness for organ retention to achieve stratified and accurate treatment.This article will review the re-lated research background,basic and clinical research progress and existing problems of iTNT in LARC.