A promising new treatment for dMMR stage II or III rectal cancer. A new clinical trial in the United States demonstrates a clinical complete response following the administration of a single agent immunotherapy, dostarlimab, in patients with mismatch repair deficient (dMMR) stage II or III rectal cancer. All patients showed no progression, recurrence or serious side effects, and did not require chemotherapy, radiation or surgery, in the follow-up period. Around 5-10% of rectal cancers are microsatellite instability-high (MSI-H) or dMMR. These cancers are relatively resistant to chemotherapy, which forms part of the current standard of care for stage II and III rectal cancer. While a longer follow up period is needed to assess the duration of the response, the results are promising. |