Total neoadjuvant therapy involving checkpoint inhibitors in locally advanced MSI/dMMR rectal cancer - a case report.

Background: Typically, the management of locally advanced rectal cancer consists of neoadjuvant chemoradiotherapy, followed by surgery and adjuvant chemotherapy. In addition to neoadjuvant chemoradiotherapy, total neoadjuvant therapy (TNT) involving radiotherapy and combined chemotherapy has been increasingly used and shown to reduce the risk of distant metastasis and improve local control. Patients with microsatellite instability and deficient mismatch repair (MSI/dMMR) tumors represent a specific group that benefits from different approaches if TNT is considered.