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.
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.
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.