In a patient with dMMR rectal adenocarcinoma, does the use of palliative RT for bleeding (5 Gy x 5) preclude the use of immunotherapy?

In dMMR rectal adenocarcinoma, short-course palliative pelvic radiotherapy is the faster, more reliable tool for controlling tumor bleeding than checkpoint inhibitor immunotherapy due to a direct hemostatic effect with bleeding-control rates of roughly 81–100% over days to a few weeks. Immunotherapy...

I would hesitate to use palliative radiation for patients with dMMR rectal cancer as long as possible because there are many patients who could be treated with immunotherapy alone for their disease and avoid long-term toxicity from chemotherapy, radiation, and surgery (Cercek et al., PMID 40293177)....

Radiation does not preclude ICI therapy. There are numerous trials showing no negative interaction and possible synergy across many tumor types.

Short-course hypofractionated radiation is both rapidly effective and does not delay systemic therapy, especially in this setting. But we should consider p...