Despite lacking direct comparative trials in endometrial cancer, some oncologists prefer PD-1 inhibitors (like pembrolizumab) over PD-L1 inhibitors. This preference stems from observing higher single-agent activity in smaller studies and a clinical belief that PD-1s may be more potent for this specific cancer.
Unlike other cancers, re-treating with immunotherapy after recurrence is considered a viable strategy for dMMR endometrial cancer. Experts theorize that these tumors are constantly evolving and may benefit from a "re-education" of the immune system, challenging the conventional wisdom that progression on a drug class means permanent resistance.
Clinicians anecdotally report that immunotherapy is changing the pattern of recurrence in endometrial cancer. Instead of widespread disease, patients often develop isolated recurrences in a single location. This shift allows for the use of local therapies, like radiation, to treat the single spot while continuing the effective systemic immunotherapy.
Clinicians observe that even when immunotherapy leads to a complete response in metastatic endometrial cancer sites, residual disease often persists in the uterus. This suggests the uterine environment is uniquely resistant, making hysterectomy necessary even when a patient appears to be systemically disease-free.
For dMMR endometrial cancer patients on combination therapy, clinicians are quicker to reduce or stop chemotherapy (like taxanes) when side effects arise. This practice reflects a growing confidence that immunotherapy is the primary driver of efficacy in this subgroup, allowing for a reduction in chemotherapy-related toxicity.