MSI-H Colorectal Cancer Rarely Recurs After Immunotherapy Cessation

THURSDAY, Dec. 21, 2023 (HealthDay News) -- Most patients with microsatellite instability-high (MSI-H) colorectal cancer do not have recurrence after cessation of immunotherapy treatment, according to a study published in the December issue of Cancer Research Communications.

Kristen Simmons, M.D., from the Baylor College of Medicine in Houston, and colleagues reviewed records from patients with advanced MSI-H colorectal cancer from The University of Texas MD Anderson Cancer Center who received immunotherapy between 2014 and 2022 and stopped after prolonged clinical benefit. Data were reviewed for 64 patients with MSI-H colorectal cancer without progression on immunotherapy: 48 and 16 received an anti-programmed death-ligand 1 antibody alone or in combination with an anti-cytotoxic T lymphocyte antigen 4 antibody, respectively.

The median immunotherapy exposure was 17.6 months. The researchers found that 88 percent of the 64 patients remained without disease progression after a median follow-up of 22.6 months after stopping immunotherapy. There was an association observed between lung metastases with recurrence/progression (odds ratio, 6.1), but no associations were noted for coexisting mutation, primary tumor sidedness, and immunotherapy.

"These data provide important information that oncologists can use for guiding discussions with patients with MSI-H/mismatch repair deficiency colorectal cancer by providing clearer numbers for the likelihood of progression should they decide to stop their immunotherapy treatment," senior author Van Karlyle Morris, M.D., from the University of Texas MD Anderson Cancer Center in Houston, said in a statement. "If you tell patients that, based on these data, there's an 88 percent chance that their cancer won't come back if they come off of therapy, I think they may be more accepting of that decision to stop treatment."

Several authors disclosed ties to the biopharmaceutical industry.

Abstract/Full Text