Concurrent RB1 Loss and BRCA-Deficiency Predicts Enhanced Immunological Response and Long-Term Survival in Tubo-Ovarian High-Grade Serous Carcinoma.

PURPOSE: To evaluate RB1 expression and survival across ovarian carcinoma histotypes, and how co-occurrence of BRCA1 or BRCA2 (BRCA) alterations and RB1 loss influences survival in tubo-ovarian high-grade serous carcinoma (HGSC). EXPERIMENTAL DESIGN: RB1 protein expression was classified by immunohistochemistry in ovarian carcinomas of 7436 patients from the Ovarian Tumor Tissue Analysis consortium. We examined RB1 expression and germline BRCA status in a subset of 1134 HGSC, and related genotype to overall survival (OS), tumor-infiltrating CD8+ lymphocytes and transcriptomic subtypes. Using CRISPR-Cas9, we deleted RB1 in HGSC cells with and without BRCA1 alterations to model co-loss with treatment response. We performed whole-genome and transcriptome data analyses on 126 primary HGSC to characterize tumors with concurrent BRCA-deficiency and RB1 loss. RESULTS: RB1 loss was associated with longer OS in HGSC, but with poorer prognosis in endometrioid ovarian carcinoma. Patients with HGSC harboring both RB1 loss and pathogenic germline BRCA variants had superior OS compared to patients with either alteration alone, and their median OS was three times longer than those without pathogenic BRCA variants and retained RB1 expression (9.3 vs. 3.1 years). Enhanced sensitivity to cisplatin and paclitaxel was seen in BRCA1-altered cells with RB1 knockout. Combined RB1 loss and BRCA-deficiency correlated with transcriptional markers of enhanced interferon response, cell-cycle deregulation, and reduced epithelial-mesenchymal transition. CD8+ lymphocytes were most prevalent in BRCA-deficient HGSC with co-loss of RB1. CONCLUSIONS: Co-occurrence of RB1 loss and BRCA-deficiency was associated with exceptionally long survival in patients with HGSC, potentially due to better treatment response and immune stimulation.

Feasibility and cost-effectiveness of genetic counselling for all patients with newly diagnosed ovarian cancer: a single-centre retrospective study.

BACKGROUND AND AIMS OF THE STUDY: Due to its importance for treatment and potential prevention in family members, germline testing for BRCA1/2 in patients with newly diagnosed ovarian cancer is decisive and considered a standard of care. Maintenance therapy with poly(ADP-ribose) polymerase (PARP) inhibitors substantially improves progression-free survival in patients with BRCA mutations and homologous recombination-deficient tumours by inducing synthetic lethality. In Switzerland, they are licensed only for these patients. Therefore, it is crucial to test patients early while they are receiving adjuvant chemotherapy. This study aimed to determine whether genetic counselling followed by homologous recombination deficiency testing is feasible for initialising maintenance therapy within eight weeks and cost-effective in daily practice in Switzerland compared to somatic tumour analysis of all patients at diagnosis. METHODS: This single-centre retrospective study included 44 patients with newly diagnosed high-grade serous ovarian cancer of a Federation of Gynaecology and Obstetrics (FIGO) stage of IIIA-IVB diagnosed between 12/2020 and 12/2022. It collected the outcomes of genetic counselling, germline testing, and somatic Geneva test for homologous recombination deficiency. Delays in initiating maintenance therapy, total testing costs per patient, and progression-free survival were examined to assess feasibility and cost-effectiveness in clinical practice. RESULTS: Thirty-seven of 44 patients (84%) with newly diagnosed ovarian cancer received counselling, of which 34 (77%) were tested for germline BRCA and other homologous recombination repair gene mutations. Five (15%) BRCA and three (9%) other homologous recombination deficiency mutations were identified. Eleven of the remaining 26 patients (42%) had tumours with somatic homologous recombination deficiency. The mean time to the initiation of maintenance therapy of 5.2 weeks was not longer than in studies for market authorisation (SOLO1, PAOLA, and PRIMA). The mean testing costs per patient were 3880 Swiss Franks (CHF), compared to 5624 CHF if all patients were tested at diagnosis with the myChoice CDx test (p <0.0001). CONCLUSION: Using genetic counselling to consent patients with newly diagnosed ovarian cancer for germline testing fulfils the international gold standard. Subsequent somatic homologous recombination deficiency analysis complements testing and identifies more patients who will benefit from PARP inhibitor maintenance therapy. Contrary to previous health cost model studies, the procedure does not increase testing costs in the Swiss population and does not delay maintenance therapy. Therefore, all patients should be offered a primary germline analysis. The challenge for the future will be to ensure sufficient resources for prompt genetic counselling and germline testing.

Real-World Data on Institutional Implementation of Screening for Mismatch Repair Deficiency and Lynch Syndrome in Endometrial Cancer Patients.

Lynch syndrome is an inherited tumor syndrome caused by a pathogenic germline variant in DNA mismatch repair genes. As the leading cause of hereditary endometrial cancer, international guidelines recommend universal screening in women with endometrial cancer. However, testing for Lynch syndrome is not yet well established in clinical practice. The aim of this study was to evaluate adherence to our Lynch syndrome screening algorithm. A retrospective, single-center cohort study was conducted of all endometrial cancer patients undergoing surgical treatment at the Bern University Hospital, Switzerland, between 2017 and 2022. Adherence to immunohistochemical analysis of mismatch repair status, and, if indicated, to MLH1 promoter hypermethylation and to genetic counseling and testing was assessed. Of all 331 endometrial cancer patients, 102 (30.8%) were mismatch repair-deficient and 3 (0.9%) patients were diagnosed with Lynch syndrome. Overall screening adherence was 78.2%, with a notable improvement over the six years from 61.4% to 90.6%. A major reason for non-adherence was lack of provider recommendation for testing, with advanced patient age as a potential patient risk factor. Simplification of the algorithm through standardized reflex screening was recommended to provide optimal medical care for those affected and to allow for cascading testing of at-risk relatives.

Reviving peritoneal cytology: Exploring its role in endometrial cancer molecular classification.

OBJECTIVE: The prognostic significance of positive peritoneal cytology in endometrial cancer has long been debated. In 2009, the Fédération Internationale de Gynécologie et d'Obstétrique (FIGO) removed cytology as a staging criterion from the endometrial cancer staging system. However, there is still evidence that positive peritoneal cytology may decrease survival among patients with endometrial cancer. The aim of this study was to determine the prognostic significance of positive peritoneal cytology among the different molecular subgroups. METHODS: This study included patients with endometrial cancer who underwent primary surgical treatment between 2004 and 2015 at the Bern University Hospital, Switzerland, with molecular classification of the primary tumor and peritoneal cytology performed. RESULTS: A total, 250 patients with endometrial cancer were enrolled. Peritoneal cytology was assessed in 206 patients, of whom 24% were positive: 25% of the POLEmut, 16% of the MMRd, 41% of the p53abn, and 24% of the NSMP cases. The mean follow-up was 128.7 months. Presence of positive peritoneal cytology was associated with significantly decreased mean recurrence-free and overall survival in patients with p53abn (p = .003 and p = .001) and NSMP (p = .020 and p = .049) endometrial cancer. In multivariable Cox regression analysis, positive peritoneal cytology remained an independent predictor of recurrence (p = .033) and death (p = .008) in p53abn endometrial cancer patients. CONCLUSION: Positive peritoneal cytology is associated with worse oncologic outcomes in NSMP and p53abn endometrial cancer and remains an independent predictor of recurrence and death in patients with p53abn endometrial cancer.

Concurrent RB1 loss and BRCA-deficiency predicts enhanced immunological response and long-term survival in tubo-ovarian high-grade serous carcinoma.

Background: Somatic loss of the tumour suppressor RB1 is a common event in tubo-ovarian high-grade serous carcinoma (HGSC), which frequently co-occurs with alterations in homologous recombination DNA repair genes including BRCA1 and BRCA2 (BRCA). We examined whether tumour expression of RB1 was associated with survival across ovarian cancer histotypes (HGSC, endometrioid (ENOC), clear cell (CCOC), mucinous (MOC), low-grade serous carcinoma (LGSC)), and how co-occurrence of germline BRCA pathogenic variants and RB1 loss influences long-term survival in a large series of HGSC. Patients and methods: RB1 protein expression patterns were classified by immunohistochemistry in epithelial ovarian carcinomas of 7436 patients from 20 studies participating in the Ovarian Tumor Tissue Analysis consortium and assessed for associations with overall survival (OS), accounting for patient age at diagnosis and FIGO stage. We examined RB1 expression and germline BRCA status in a subset of 1134 HGSC, and related genotype to survival, tumour infiltrating CD8+ lymphocyte counts and transcriptomic subtypes. Using CRISPR-Cas9, we deleted RB1 in HGSC cell lines with and without BRCA1 mutations to model co-loss with treatment response. We also performed genomic analyses on 126 primary HGSC to explore the molecular characteristics of concurrent homologous recombination deficiency and RB1 loss. Results: RB1 protein loss was most frequent in HGSC (16.4%) and was highly correlated with RB1 mRNA expression. RB1 loss was associated with longer OS in HGSC (hazard ratio [HR] 0.74, 95% confidence interval [CI] 0.66-0.83, P = 6.8 ×10-7), but with poorer prognosis in ENOC (HR 2.17, 95% CI 1.17-4.03, P = 0.0140). Germline BRCA mutations and RB1 loss co-occurred in HGSC (P < 0.0001). Patients with both RB1 loss and germline BRCA mutations had a superior OS (HR 0.38, 95% CI 0.25-0.58, P = 5.2 ×10-6) compared to patients with either alteration alone, and their median OS was three times longer than non-carriers whose tumours retained RB1 expression (9.3 years vs. 3.1 years). Enhanced sensitivity to cisplatin (P < 0.01) and paclitaxel (P < 0.05) was seen in BRCA1 mutated cell lines with RB1 knockout. Among 126 patients with whole-genome and transcriptome sequence data, combined RB1 loss and genomic evidence of homologous recombination deficiency was correlated with transcriptional markers of enhanced interferon response, cell cycle deregulation, and reduced epithelial-mesenchymal transition in primary HGSC. CD8+ lymphocytes were most prevalent in BRCA-deficient HGSC with co-loss of RB1. Conclusions: Co-occurrence of RB1 loss and BRCA mutation was associated with exceptionally long survival in patients with HGSC, potentially due to better treatment response and immune stimulation.

Real-World Data Assessing the Impact of Lymphovascular Space Invasion on the Diagnostic Performance of Sentinel Lymph Node Mapping in Endometrial Cancer.

BACKGROUND: SLN mapping has emerged as a standard of care in endometrial cancer due to its high sensitivity and significant reduction in morbidity. Although lymphovascular space invasion (LVSI) is a known risk factor for lymph node metastasis and recurrence, evidence on the reliability of SLN mapping in LVSI-positive patients is scarce. The aim of this study was to determine the impact of LVSI on the diagnostic performance of SLN mapping. METHODS: This retrospective cohort study included patients with endometrial cancer who underwent primary surgical treatment at the Bern University Hospital, Switzerland, between 2012 and 2022. RESULTS: LVSI was present in 22% of patients and was significantly associated with lymph node metastasis (p < 0.001) and recurrence (p < 0.001). In node-negative patients with only SLN mapping performed, LVSI was an independent predictor of recurrence during multivariable Cox regression analysis (p = 0.036). The negative predictive value of SLN mapping was 91.5% and was significantly lower in tumors with LVSI (75.0%) compared to LVSI-negative tumors (95.6%, p = 0.004). CONCLUSION: The presence of LVSI was significantly associated with worse oncological outcomes. LVSI was an independent predictor of recurrence in node-negative patients with only SLN mapping performed. Furthermore, the negative predictive value of SLN mapping was significantly lower in LVSI-positive tumors.

The genomic and immune landscape of long-term survivors of high-grade serous ovarian cancer.

Fewer than half of all patients with advanced-stage high-grade serous ovarian cancers (HGSCs) survive more than five years after diagnosis, but those who have an exceptionally long survival could provide insights into tumor biology and therapeutic approaches. We analyzed 60 patients with advanced-stage HGSC who survived more than 10 years after diagnosis using whole-genome sequencing, transcriptome and methylome profiling of their primary tumor samples, comparing this data to 66 short- or moderate-term survivors. Tumors of long-term survivors were more likely to have multiple alterations in genes associated with DNA repair and more frequent somatic variants resulting in an increased predicted neoantigen load. Patients clustered into survival groups based on genomic and immune cell signatures, including three subsets of patients with BRCA1 alterations with distinctly different outcomes. Specific combinations of germline and somatic gene alterations, tumor cell phenotypes and differential immune responses appear to contribute to long-term survival in HGSC.

Going to extremes: determinants of extraordinary response and survival in patients with cancer.

Research into factors affecting treatment response or survival in patients with cancer frequently involves cohorts that span the most common range of clinical outcomes, as such patients are most readily available for study. However, attention has turned to highly unusual patients who have exceptionally favourable or atypically poor responses to treatment and/or overall survival, with the expectation that patients at the extremes may provide insights that could ultimately improve the outcome of individuals with more typical disease trajectories. While clinicians can often recount surprising patients whose clinical journey was very unusual, given known clinical characteristics and prognostic indicators, there is a lack of consensus among researchers on how best to define exceptional patients, and little has been proposed for the optimal design of studies to identify factors that dictate unusual outcome. In this Opinion article, we review different approaches to identifying exceptional patients with cancer and possible study designs to investigate extraordinary clinical outcomes. We discuss pitfalls with finding these rare patients, including challenges associated with accrual of patients across different treatment centres and time periods. We describe recent molecular and immunological factors that have been identified as contributing to unusual patient outcome and make recommendations for future studies on these intriguing patients.