Mismatch repair deficiency, next-generation sequencing-based microsatellite instability, and tumor mutational burden as predictive biomarkers for immune checkpoint inhibitor effectiveness in frontline treatment of advanced stage endometrial cancer.

OBJECTIVE: Molecular profiling is developing to inform treatment in endometrial cancer. Using real world evidence, we sought to evaluate frontline immune checkpoint inhibitor vs chemotherapy effectiveness in advanced endometrial cancer, stratified by Tumor Mutational Burden (TMB) ≥10 mut/MB and microsatellite instability (MSI). METHODS: Patients with advanced endometrial cancer in the US-based de-identified Flatiron Health-Foundation Medicine Clinico-Genomic Database were included. Data originated from patients treated between January 2011- March 2022 at 280 US clinics. Next-generation sequencing assays were performed via FoundationOne or FoundationOneCDx. Longitudinal clinical data were derived from electronic health records. Immune checkpoint inhibitor treatment included pembrolizumab, dostarlimab, and nivolumab monotherapies. Time to next treatment, time to treatment discontinuation, and overall survival were assessed with the log-rank test and Cox proportional hazard models with adjusted hazard ratios (aHR) for known prognostic factors. We used the Likelihood ratio test to compare biomarker performance. RESULTS: A total of 343 patients received chemotherapy and 28 received immune checkpoint inhibitor monotherapy as frontline treatment. Patients who received monotherapy were more likely to be stage III at diagnosis (immune checkpoint inhibitor: 54.6% vs chemotherapy: 15.0%; p<0.001) and more likely to test MSI-high via next-generation sequencing (immune checkpoint inhibitor: 53.6% vs chemotherapy: 19.2%; p<0.001). In MSI-high cancers, single-agent immune checkpoint inhibitor had a more favorable time to next treatment (aHR: 0.18, p=0.001) and overall survival (aHR 0.29, p=0.045). Additional analyses on 70 unique tumor specimens revealed mismatch repair deficiency (dMMR) via immunohistochemistry and MSI-high via next-generation sequencing concordance (91%), with nominal improvement of MSI over dMMR to predict time to treatment discontinuation (p=0.030), time to next treatment (p=0.032), and overall survival (p=0.22). MSI status was concordant with tumor mutational burden ≥10 in 94.3% of cases. CONCLUSION: Immune checkpoint inhibitors may have improved efficacy over chemotherapy in frontline treatment for advanced endometrial cancer defined by MSI-high using next-generation sequencing as a nominally better predictor of outcomes than dMMR with immunohistochemistry. This provides the biologic rationale of active phase III trials.

Does Lymph Node Dissection Impact Adjuvant Treatment or Survival Outcomes in High-Risk Endometrial Cancers?

Objectives Lymphadenectomy does not improve overall survival outcomes in patients with low-risk endometrial cancers. Sentinel node mapping has a high detection rate and accuracy; however, its prognostic implications have not been well explored. We evaluated the overall survival and therapies received by patients undergoing varied lymph node dissection approaches for high-risk endometrial cancers. Methods Retrospective review of grade 3 endometrioid and high-grade non-endometrioid cancers at one institution over ten years. Patients who received neoadjuvant therapy and/or debulking of only grossly abnormal lymph nodes were excluded. Data was abstracted from electronic medical records. Chi-squared tests and survival analyses were used to compare groups. Results One hundred and fifty-three patients with grade 3 endometrioid, serous, clear cell, carcinosarcoma, or mixed high-grade on final pathology were identified; 16 had no lymph node dissection, 26 had sentinel lymph nodes, and 111 had complete lymph node dissection. Patients with open surgery were more likely to have complete nodes than sentinel nodes when compared to a minimally invasive approach (p<0.001). Sentinel nodal dissection significantly impacted the utilization of, or modality choice, in adjuvant therapy (p=0.051). Recurrence-free survival and cancer-specific overall survival were not significantly different across the three nodal-assessment groups. Conclusions  Sentinel lymph node dissection in high-risk endometrial cancers led to no significant differences in recurrence-free survival or cancer-specific overall survival. While limited by sample size and its retrospective nature, results from this single-institution study are hypothesis-generating and prompt consideration of non-inferiority trials. Performing the least invasive surgery possibly can lead to fewer complications while maintaining overall survival outcomes.

Strategies for Optimizing Perioperative Pain Management for the Cancer Patient.

Effective management of pain in patients with cancer impacts quality of life and willingness to receive disease-directed treatment. This review focuses on preoperative, intraoperative, and postoperative strategies for management of perioperative pain in the patient with cancer. Managing perioperative pain in special populations, including patients with preoperative opioid use, those with a history of substance abuse, and patients near the end of life are also addressed.

Can we safely forgo hysterectomy in non-fertility-sparing surgery for borderline ovarian tumors?

Forgoing hysterectomy as part of borderline ovarian tumor (BOT) staging is considered appropriate for fertility preservation. We evaluated whether forgoing hysterectomy may also be acceptable in non-fertility-sparing surgery by evaluating the frequency of uterine involvement and the rate of recurrence involving the uterus. A review of all BOTs at one institution over ten years (2009-2019) was performed. Patients with hysterectomy prior to BOT diagnosis were excluded. Data were abstracted from electronic medical records. Bivariate statistics were used to compare groups. 129 patients with BOT on final pathology were identified. 67 cases included hysterectomy. Reasons for no hysterectomy (n = 62) included fertility preservation (40), benign intraoperative frozen pathology (4), patient preference (3), comorbidities (7), and unknown (8). Four of 67 (6.0%) uterine specimens had non-invasive serosal implants, of which two had grossly visible uterine involvement and all four had grossly visible extrauterine peritoneal disease. 12 of 129 (9.3%) patients had documented recurrence, of which all had uterine preservation at the time of initial surgery. Of the 12 recurrences with uterus in situ, none were documented to involve the uterus, and all were composed of non-invasive implants. In patients with BOT grossly confined to ovaries at the time of surgery, we found no cases of uterine involvement. We found no cases in which microscopic uterine serosal involvement changed stage and no cases of recurrence involving the uterus. Hysterectomy may be able to be safely excluded from non-fertility-sparing surgery for BOTs, particularly when disease is grossly confined to the ovaries.