Advancements in rectal and colon cancer treatment and monitoring

Recent clinical developments have introduced new ways to manage and treat rectal and colon cancers through DNA monitoring and immunotherapy.

A phase 2 CO. 28 trial published in JCO Precision Oncology investigated the use of circulating tumor DNA (ctDNA) to guide surgical decisions for patients with node-negative rectal cancer. The study found that after three months of chemotherapy, the detection of ctDNA dropped from 45.8% to 8.7%. Patients who still exhibited detectable ctDNA after chemotherapy were recommended for total mesorectal excision (TME), a major surgery, whereas those without detectable ctDNA were significantly less likely to require it. This approach aims to preserve bowel and sexual function by avoiding extensive surgery when possible.

Separately, the U.S. Food and Drug Administration has approved atezolizumab (Tecentriq) in combination with chemotherapy for patients with stage III mismatch repair deficient (dMMR) colon cancer. Based on a federally sponsored trial, this adjuvant immunotherapy regimen was shown to halve the risk of cancer recurrence or death compared to chemotherapy alone. The treatment involves six months of combined therapy followed by up to six months of atezolizumab alone, targeting the approximately 15% of colon cancer patients with dMMR or MSI-H tumor features.