Mismatch Repair Status Predicts Endometrial Cancer Outcomes

TOPLINE:

A retrospective study found that patients with mismatch repair (MMR)-deficient advanced or recurrent endometrial cancer had numerically longer overall survival (OS) than those with MMR-proficient tumours.

METHODOLOGY:

• Researchers analysed 731 patients with advanced (n = 575) or recurrent (n = 156) endometrial cancer (mean age, 68.26 years; 81.66% White) using data from the UK Arcturis dataset between January 2000 and September 2023.
• Patients were stratified on the basis of their MMR status as those with deficient MMR (5.75%), proficient MMR (16.96%), or unknown MMR status (77.29%).
• The most common treatment for MMR-deficient patients was surgery (30.95%), and that for MMR-proficient patients was surgery plus chemotherapy (24.19%). Chemotherapy was administered as a second-line therapy in 14.77% and as a third-line therapy in 3.42% of patients; carboplatin plus paclitaxel comprised 75.10% of all first-line regimens.
• Study outcomes were the time to next treatment (TTNT) and OS.
• A sensitivity analysis was also performed in patients treated on or after January 2019 to assess outcomes following the launch of NICE Lynch syndrome testing guidelines.

TAKEAWAY:

• The overall median TTNT from first-line therapy was 1.22 years. The median TTNT at first-line therapy was 1.17 years for the MMR-deficient group, 1.03 years for the MMR-proficient group, and 1.26 years for patients with unknown MMR status.
• Post-NICE guidelines, the TTNT from first-line therapy was 0.98 years for MMR-deficient patients, 0.93 years for MMR-proficient patients, and 1.28 years for those with unknown MMR status.
• The median OS from first-line therapy was 1.80 years for the overall cohort; on the basis of MMR status, it was 4.25 years for the deficient subgroup, 2.36 years for the proficient subgroup, and 1.64 years for patients with unknown MMR status.
• Post-NICE guidelines, the median OS was not reached for MMR-deficient patients; it was 2.36 years for MMR-proficient patients and 1.74 years for those with unknown MMR status.

IN PRACTICE:

“This large study of patients with advanced/recurrent EC [endometrial cancer] from selected NHS trusts in England benchmarked treatment patterns and outcomes,” the authors wrote. However, they added that “although this analysis is suggestive of a difference in outcomes between MMR subgroups, attainment of MMR status was low, and further research comparing real-world outcomes based on molecular profile, including MMR subgroups, is warranted.”

SOURCE:

This study was led by Jamie Wallis, Arcturis Data, Oxfordshire, England. It was published online on August 01, 2025, in Oncology and Therapy.

LIMITATIONS:

The small sample size and the short follow-up period of the MMR subgroups significantly affected result interpretation. Staging information and clinical progression data were not available, requiring the use of TTNT as a proxy for progression-free survival. Additionally, the high proportion of White patients in the study reflected disparities in care.

DISCLOSURES:

This study was funded by GSK. Four authors reported being employees of and holding financial equities in GSK. Additional disclosures are noted in the original article.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.