Conditional survival data from the RUBY trial is highly encouraging. For MSI-high patients, reaching the one-year survival mark implies an 84% chance of long-term survival, which skyrockets to nearly 95% for those who reach the three-year landmark.

Following the Keynote B21 trial, clinicians have become more selective with adjuvant immunotherapy in endometrial cancer. The study showed minimal benefit for pMMR patients and less impressive gains overall in its lower-risk population compared to advanced disease trials. This has led to a practice of reserving adjuvant chemo-IO primarily for stage 3 dMMR patients.

While antibody-drug conjugates (ADCs) are an exciting frontier in endometrial cancer, a critical challenge is emerging: determining optimal duration for maintenance therapies. Experts are concerned about committing patients to long-term, potentially toxic treatments without clear stopping rules, a key question for future trials.

The four TCGA molecular profiles (e.g., POLE-mutated, p53-abnormal) have evolved beyond predicting outcomes to actively guiding treatment, such as de-escalating therapy for low-risk groups and escalating for high-risk ones.

Potent responses to chemo-immunotherapy are promoting a shift toward neoadjuvant treatment for advanced endometrial cancer. Waiting six cycles often achieves a response sufficient to allow for a minimally invasive hysterectomy instead of a more extensive primary debulking surgery.

In dMMR endometrial cancer, data from the RUBY trial shows very few progressions after the first year. This "conditional survival" insight suggests that the current standard of 2-3 years of maintenance immunotherapy may be longer than necessary.

While immunotherapy is transformational for DMMR endometrial cancer, its benefit is much smaller for the PMMR majority (two-thirds of patients). This reality requires more nuanced patient counseling and selective use in this population.

Clinical trials show a sustained overall survival benefit for upfront chemo-immunotherapy in dMMR patients, even with over 90% of the placebo group receiving immunotherapy upon progression. This demonstrates that delaying immunotherapy fails to rescue outcomes, making upfront use critical.

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.