Comparing niraparib versus platinum-taxane doublet chemotherapy as neoadjuvant treatment in patients with newly diagnosed homologous recombination-deficient stage III/IV ovarian cancer: study protocol for cohort C of the open-label, phase 2, randomized controlled multicenter OPAL trial

BACKGROUND

Maintenance therapy with niraparib, a poly(ADP-ribose) polymerase inhibitor, has been shown to extend progression-free survival in patients with newly diagnosed advanced ovarian cancer who responded to first-line platinum-based chemotherapy, regardless of biomarker status. However, there are limited data on niraparib's efficacy and safety in the neoadjuvant setting. The objective of Cohort C of the OPAL trial (OPAL-C) is to evaluate the efficacy, safety, and tolerability of neoadjuvant niraparib treatment compared with neoadjuvant platinum-taxane doublet chemotherapy in patients with newly diagnosed stage III/IV ovarian cancer with confirmed homologous recombination-deficient tumors.

METHODS

OPAL is an ongoing global, multicenter, randomized, open-label, phase 2 trial. In OPAL-C, patients will be randomized 1:1 to receive three 21-day cycles of either neoadjuvant niraparib or platinum-taxane doublet neoadjuvant chemotherapy per standard of care. Patients with a complete or partial response per Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) will then undergo interval debulking surgery; patients with stable disease may proceed to interval debulking surgery or alternative therapy at the investigator's discretion. Patients with disease progression will exit the study treatment and proceed to alternative therapy at the investigator's discretion. After interval debulking surgery, all patients will receive up to three 21-day cycles of platinum-taxane doublet chemotherapy followed by niraparib maintenance therapy for up to 36 months. Adult patients with newly diagnosed stage III/IV ovarian cancer eligible to receive neoadjuvant platinum-taxane doublet chemotherapy followed by interval debulking surgery may be enrolled. Patients must have tumors that are homologous recombination-deficient. The primary endpoint is the pre-interval debulking surgery unconfirmed overall response rate, defined as the investigator-assessed percentage of patients with unconfirmed complete or partial response on study treatment before interval debulking surgery per RECIST v1.1.

DISCUSSION

OPAL-C explores the use of niraparib in the neoadjuvant setting as an alternative to neoadjuvant platinum-taxane doublet chemotherapy to improve postsurgical residual disease outcomes for patients with ovarian cancer with homologous recombination-deficient tumors. Positive findings from this approach could significantly impact preoperative ovarian cancer therapy, particularly for patients who are ineligible for primary debulking surgery.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03574779. Registered on February 28, 2022.

Phase 1b study of mirvetuximab soravtansine, a folate receptor alpha (FRα)-targeting antibody-drug conjugate, in combination with carboplatin and bevacizumab in patients with platinum-sensitive ovarian cancer

OBJECTIVE

Evaluate the antitumor activity and safety profile of the triplet combination of mirvetuximab soravtansine (MIRV), carboplatin, and bevacizumab in recurrent, platinum-sensitive ovarian cancer.

METHODS

Participants with recurrent, platinum-sensitive epithelial ovarian, fallopian tube, or primary peritoneal cancer (1-2 prior lines of therapy) received MIRV (6 mg/kg adjusted ideal body weight), carboplatin (AUC5), and bevacizumab (15 mg/kg) once every 3 weeks. Carboplatin could be discontinued after 6 cycles per investigator discretion; continuation of MIRV+bevacizumab as maintenance therapy was permitted. Eligibility included folate receptor alpha (FRα) expression by immunohistochemistry (≥50% of cells with ≥2+ intensity; PS2+ scoring); prior bevacizumab was allowed. Tumor response, duration of response (DOR), progression-free survival (PFS), and adverse events (AEs) were assessed.

RESULTS

Forty-one participants received triplet therapy, with a median of 6, 12, and 13 cycles of carboplatin, MIRV, and bevacizumab, respectively. The confirmed objective response rate was 83% (9 complete and 25 partial responses). The median DOR was 10.9 months; median PFS was 13.5 months. AEs (any grade) occurred as expected, based on each agent's safety profile; most common were diarrhea (83%), nausea (76%), fatigue (73%), thrombocytopenia (71%), and blurred vision (68%). Most cases were mild to moderate (grade ≤2), except for thrombocytopenia, for which most drug-related discontinuations occurred, and neutropenia.

CONCLUSIONS

This triplet regimen (MIRV+carboplatin+bevacizumab) was highly active, with a tolerable AE profile in participants with recurrent, platinum-sensitive, FRα-expressing ovarian cancer. Thrombocytopenia was the primary cause of dose modifications. These outcomes compare favorably to historical data reported for platinum-based chemotherapy plus bevacizumab regimens in similar patient populations.

Maveropepimut-S, a DPX-based immune-educating therapy, shows promising and durable clinical benefit in patients with recurrent ovarian cancer, a phase 2 trial

PURPOSE

Patients with platinum resistant ovarian cancer (OvCa) respond poorly to existing therapies. Hence there is a need for more effective treatments.

METHODS

The DeCidE1 trial is a multicenter, randomized, open-label, single-arm phase 2 study to evaluate the safety and effectiveness of maveropepimut-S (MVP-S) with cyclophosphamide (CPA) in patients with recurrent ovarian cancer. Median follow-up for evaluable subjects was 4.4 months. Data were collected from March 2019 to June 2021. Subjects received two injections of 0.25 mL MVP-S 3 weeks apart, followed by one 0.1 mL doses, every 8 weeks up to progression. Oral CPA, 50 mg twice daily, was administered in repeating weekly on and off cycles.

RESULTS

Twenty-two patients were enrolled. Median age was 58 years (38-78 years). Among the evaluable population, ORR was 21% (90% CI, 7.5%-41.9%), with a DCR of 63% (90% CI, 41.8%-81.3%), including 4 (21%) patients with partial responses, 8 (42%) stable disease, and 7 (37%) progressive disease. The ORRs were consistent across subgroups based on platinum-sensitivity, and DCR was higher in the platinum-resistant subpopulation. Four stable disease patients maintained clinical benefit up to 25 months. Most treatment related adverse events (TRAEs) were grade 1 and 2 (87% of unique events). Most common AEs were injection site reactions. Eight subjects reported grade 3 and no grade 4 AEs. Survivin-specific T cell responses were observed in treated patients with clinical benefit.

CONCLUSIONS

MVP-S with intermittent low-dose CPA is well-tolerated, with clinical benefit for patients with recurrent OvCa. Observed responses are irrespective of the platinum status.

Alcohol intake and the risk of epithelial ovarian cancer

PURPOSE

To investigate the association between alcohol intake over the lifetime and the risk of overall, borderline, and invasive ovarian cancer.

METHODS

In a population-based case-control study of 495 cases and 902 controls, conducted in Montreal, Canada, average alcohol intake over the lifetime and during specific age periods were computed from a detailed assessment of the intake of beer, red wine, white wine and spirits. Multivariable logistic regression was used to estimate odds ratios (ORs) with 95% confidence intervals (CIs) for the association between alcohol intake and ovarian cancer risk.

RESULTS

For each one drink/week increment in average alcohol intake over the lifetime, the adjusted OR (95% CI) was 1.06 (1.01-1.10) for ovarian cancer overall, 1.13 (1.06-1.20) for borderline ovarian cancers and 1.02 (0.97-1.08) for invasive ovarian cancers. This pattern of association was similarly observed for alcohol intake in early (15- < 25 years), mid (25- < 40 years) and late adulthood (≥ 40 years), as well as for the intake of specific alcohol beverages over the lifetime.

CONCLUSIONS

Our results support the hypothesis that a higher alcohol intake modestly increases the risk of overall ovarian cancer, and more specifically, borderline tumours.

Safety and efficacy of mirvetuximab soravtansine, a folate receptor alpha (FRα)-targeting antibody-drug conjugate (ADC), in combination with bevacizumab in patients with platinum-resistant ovarian cancer

PURPOSE

Evaluate the antitumor activity and safety profile of the combination of mirvetuximab soravtansine and bevacizumab in patients with platinum-resistant ovarian cancer.

METHODS

Patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer, whose most recent platinum-free interval was ≤6 months, were administered mirvetuximab soravtansine (6 mg/kg adjusted ideal body weight) and bevacizumab (15 mg/kg), intravenously, once every 3 weeks. Eligibility included FRα expression by immunohistochemistry (IHC; ≥25% of cells with ≥2+ intensity). Prior bevacizumab and/or PARP inhibitor (PARPi) treatment were permitted. The primary endpoint was confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR), progression-free survival (PFS), and safety.

RESULTS

Ninety-four patients received combination treatment with mirvetuximab soravtansine and bevacizumab. Median age was 62 years (range, 39-81). Fifty-two percent had ≥3 prior therapies; 59% had prior bevacizumab; and 27% had prior PARPi. ORR was 44% (95% CI 33, 54) with 5 complete responses, median DOR 9.7 months (95% CI 6.9, 14.1), and median PFS 8.2 months (95% CI 6.8, 10.0). Treatment-related adverse events were consistent with the profiles of each agent, with the most common being blurred vision (all grades 57%; grade 3, 1%), diarrhea (54%; grade 3, 1%), and nausea (51%; grade 3, 1%).

CONCLUSION

The mirvetuximab soravtansine plus bevacizumab doublet is an active and well-tolerated regimen in patients with FRα-expressing platinum-resistant ovarian cancer. Promising activity was observed for patients regardless of level of FRα expression or prior bevacizumab. These data underscore the potential for mirvetuximab soravtansine as the combination partner of choice for bevacizumab in this setting.

Vulvar Squamous Cell Carcinoma With Sarcomatoid Features are HPV-independent Lesions: A Subset are Also Associated With TP 53-independent Lesions and Radiation Therapy

Vulvar squamous cell carcinoma of the vulva (VSCC) with sarcomatoid features is a rare variant characterized by spindle-cell morphology and occasional heterologous elements. They are difficult to evaluate due to rarity and lack unified nomenclature and histopathologic criteria. Eight cases of sarcomatoid VSCC were retrieved from archival electronic medical records from 2013 to 2021. Patients often presented at a mean age of 78-yr-old at stage FIGO (2018) III or above. The mean greatest diameter was 4.5 cm and mean depth of invasion was 11.5 mm. Spindle cells exhibited fascicular, nested, and cord-like growth patterns, though a haphazard arrangement or a mix of patterns was frequently observed. The sarcomatoid component frequently arose in the context of prior conventional VSCC treated with radiation therapy (n=6, 75% and chemotherapy (n=5, 63%) with latency periods of 5.2 and 5.4 yr, respectively. Associated lesions included differentiated vulvar intraepithelial neoplasia (n=4, 50%), lichen sclerosus (n=5, 63%), and vulvar acanthosis with altered differentiation (n=1, 13%). Immunohistochemistry showed that VSCC with sarcomatoid features aberrantly expressed p53 (n=4, 60%) through diffuse overexpression or null-type patterns. P16 was invariably negative in all cases. These findings suggest that VSCC with sarcomatoid features does not arise from the HPV-related carcinogenic pathway, and that a subset may also arise from the TP53-independent pathway. Recognizing sarcomatoid morphology in VSCC is important since it may confer an elevated risk of nodal metastasis and poorer survival. Larger studies are required to assess the etiology and prognostic implications of VSCC with sarcomatoid features.

Leiomyoma With Massive Lymphoid Infiltration: 2 Cases With Lymphocytic Vasculopathy and Angiocentric Germinal Centers

Uterine leiomyoma with massive lymphoid infiltration is characterized by a dense lymphoid infiltrate and germinal centers sparing the adjacent myometrium. Only few reports describe this entity and its etiology is unknown. This rare lesion may also exhibit lymphocytic vasculopathy but this has only been reported in the setting of GnRH agonist exposure. We report 2 cases of uterine leiomyoma with massive lymphoid infiltration in which only 1 patient was exposed to GnRH agonists. In both cases, histopathologic analysis showed thick-walled vessels with swollen endothelial cells showing evidence of intramural lymphocytic infiltration, red blood cell extravasation, and medial edema. This constellation of findings represented frank vascular damage and lymphocytic vasculopathy. Our findings suggest that lymphocytic vasculopathy in these lesions may be secondary to factors other than GnRH agonists. Furthermore, both cases showed an angiocentric disposition of germinal centers that has scarcely been alluded to in prior reports. This finding may provide a clue in accurately recognizing leiomyoma with massive lymphoid infiltration. Recognition of this lesion will allow one to avoid mistaking it for mimickers such as inflammatory myofibroblastic tumor, lymphoid malignancies, or other inflammatory processes.

Molecular Genetic Characteristics of FANCI, a Proposed New Ovarian Cancer Predisposing Gene

FANCI was recently identified as a new candidate ovarian cancer (OC)-predisposing gene from the genetic analysis of carriers of FANCI c.1813C>T; p.L605F in OC families. Here, we aimed to investigate the molecular genetic characteristics of FANCI, as they have not been described in the context of cancer. We first investigated the germline genetic landscape of two sisters with OC from the discovery FANCI c.1813C>T; p.L605F family (F1528) to re-affirm the plausibility of this candidate. As we did not find other conclusive candidates, we then performed a candidate gene approach to identify other candidate variants in genes involved in the FANCI protein interactome in OC families negative for pathogenic variants in BRCA1, BRCA2, BRIP1, RAD51C, RAD51D, and FANCI, which identified four candidate variants. We then investigated FANCI in high-grade serous ovarian carcinoma (HGSC) from FANCI c.1813C>T carriers and found evidence of loss of the wild-type allele in tumour DNA from some of these cases. The somatic genetic landscape of OC tumours from FANCI c.1813C>T carriers was investigated for mutations in selected genes, copy number alterations, and mutational signatures, which determined that the profiles of tumours from carriers were characteristic of features exhibited by HGSC cases. As other OC-predisposing genes such as BRCA1 and BRCA2 are known to increase the risk of other cancers including breast cancer, we investigated the carrier frequency of germline FANCI c.1813C>T in various cancer types and found overall more carriers among cancer cases compared to cancer-free controls (p = 0.007). In these different tumour types, we also identified a spectrum of somatic variants in FANCI that were not restricted to any specific region within the gene. Collectively, these findings expand on the characteristics described for OC cases carrying FANCI c.1813C>T; p.L605F and suggest the possible involvement of FANCI in other cancer types at the germline and/or somatic level.

Genetic analyses of DNA repair pathway associated genes implicate new candidate cancer predisposing genes in ancestrally defined ovarian cancer cases

Not all familial ovarian cancer (OC) cases are explained by pathogenic germline variants in known risk genes. A candidate gene approach involving DNA repair pathway genes was applied to identify rare recurring pathogenic variants in familial OC cases not associated with known OC risk genes from a population exhibiting genetic drift. Whole exome sequencing (WES) data of 15 OC cases from 13 families tested negative for pathogenic variants in known OC risk genes were investigated for candidate variants in 468 DNA repair pathway genes. Filtering and prioritization criteria were applied to WES data to select top candidates for further analyses. Candidates were genotyped in ancestry defined study groups of 214 familial and 998 sporadic OC or breast cancer (BC) cases and 1025 population-matched controls and screened for additional carriers in 605 population-matched OC cases. The candidate genes were also analyzed in WES data from 937 familial or sporadic OC cases of diverse ancestries. Top candidate variants in ERCC5, EXO1, FANCC, NEIL1 and NTHL1 were identified in 5/13 (39%) OC families. Collectively, candidate variants were identified in 7/435 (1.6%) sporadic OC cases and 1/566 (0.2%) sporadic BC cases versus 1/1025 (0.1%) controls. Additional carriers were identified in 6/605 (0.9%) OC cases. Tumour DNA from ERCC5, NEIL1 and NTHL1 variant carriers exhibited loss of the wild-type allele. Carriers of various candidate variants in these genes were identified in 31/937 (3.3%) OC cases of diverse ancestries versus 0-0.004% in cancer-free controls. The strategy of applying a candidate gene approach in a population exhibiting genetic drift identified new candidate OC predisposition variants in DNA repair pathway genes.

A Randomized, Phase III Trial to Evaluate Rucaparib Monotherapy as Maintenance Treatment in Patients With Newly Diagnosed Ovarian Cancer (ATHENA-MONO/GOG-3020/ENGOT-ov45)

PURPOSE

ATHENA (ClinicalTrials.gov identifier: NCT03522246) was designed to evaluate rucaparib first-line maintenance treatment in a broad patient population, including those without BRCA1 or BRCA2 (BRCA) mutations or other evidence of homologous recombination deficiency (HRD), or high-risk clinical characteristics such as residual disease. We report the results from the ATHENA-MONO comparison of rucaparib versus placebo.

METHODS

Patients with stage III-IV high-grade ovarian cancer undergoing surgical cytoreduction (R0/complete resection permitted) and responding to first-line platinum-doublet chemotherapy were randomly assigned 4:1 to oral rucaparib 600 mg twice a day or placebo. Stratification factors were HRD test status, residual disease after chemotherapy, and timing of surgery. The primary end point of investigator-assessed progression-free survival was assessed in a step-down procedure, first in the HRD population (BRCA-mutant or BRCA wild-type/loss of heterozygosity high tumor), and then in the intent-to-treat population.

RESULTS

As of March 23, 2022 (data cutoff), 427 and 111 patients were randomly assigned to rucaparib or placebo, respectively (HRD population: 185 v 49). Median progression-free survival (95% CI) was 28.7 months (23.0 to not reached) with rucaparib versus 11.3 months (9.1 to 22.1) with placebo in the HRD population (log-rank P = .0004; hazard ratio [HR], 0.47; 95% CI, 0.31 to 0.72); 20.2 months (15.2 to 24.7) versus 9.2 months (8.3 to 12.2) in the intent-to-treat population (log-rank P < .0001; HR, 0.52; 95% CI, 0.40 to 0.68); and 12.1 months (11.1 to 17.7) versus 9.1 months (4.0 to 12.2) in the HRD-negative population (HR, 0.65; 95% CI, 0.45 to 0.95). The most common grade ≥ 3 treatment-emergent adverse events were anemia (rucaparib, 28.7% v placebo, 0%) and neutropenia (14.6% v 0.9%).

CONCLUSION

Rucaparib monotherapy is effective as first-line maintenance, conferring significant benefit versus placebo in patients with advanced ovarian cancer with and without HRD.

Unilateral inguinofemoral lymphadenectomy in patients with early-stage vulvar squamous cell carcinoma and a unilateral metastatic sentinel lymph node is safe

OBJECTIVE

Optimal management of the contralateral groin in patients with early-stage vulvar squamous cell carcinoma (VSCC) and a metastatic unilateral inguinal sentinel lymph node (SN) is unclear. We analyzed patients who participated in GROINSS-V I or II to determine whether treatment of the contralateral groin can safely be omitted in patients with a unilateral metastatic SN.

METHODS

We selected the patients with a unilateral metastatic SN from the GROINSS-V I and II databases. We determined the incidence of contralateral additional non-SN metastases in patients with unilateral SN-metastasis who underwent bilateral inguinofemoral lymphadenectomy (IFL). In those who underwent only ipsilateral groin treatment or no further treatment, we determined the incidence of contralateral groin recurrences during follow-up.

RESULTS

Of 1912 patients with early-stage VSCC, 366 had a unilateral metastatic SN. Subsequently, 244 had an IFL or no treatment of the contralateral groin. In seven patients (7/244; 2.9% [95% CI: 1.4%-5.8%]) disease was diagnosed in the contralateral groin: five had contralateral non-SN metastasis at IFL and two developed an isolated contralateral groin recurrence after no further treatment. Five of them had a primary tumor ≥30 mm. Bilateral radiotherapy was administered in 122 patients, of whom one (1/122; 0.8% [95% CI: 0.1%-4.5%]) had a contralateral groin recurrence.

CONCLUSION

The risk of contralateral lymph node metastases in patients with early-stage VSCC and a unilateral metastatic SN is low. It appears safe to limit groin treatment to unilateral IFL or inguinofemoral radiotherapy in these cases.

Olaparib treatment for platinum-sensitive relapsed ovarian cancer by BRCA mutation and homologous recombination deficiency status: Phase II LIGHT study primary analysis

OBJECTIVE

Olaparib treatment resulted in significant improvement in objective response rates (ORRs) and progression-free survival (PFS) over non‑platinum chemotherapy in patients with BRCA1/BRCA2-mutated (BRCAm) platinum-sensitive relapsed ovarian cancer (PSROC) and ≥2 prior lines of platinum-based chemotherapy in the phase III SOLO3 study. LIGHT (NCT02983799) prospectively evaluated olaparib treatment for patients with PSROC and known BRCAm and homologous recombination deficiency (HRD) status.

METHODS

In this phase II open-label multicenter study, patients with PSROC and ≥1 prior line of platinum-based chemotherapy were assigned to cohorts by presence of germline BRCAm (gBRCAm), somatic BRCAm (sBRCAm), HRD-positive tumors without BRCAm, or HRD-negative tumors. The primary endpoint was investigator-assessed ORR. Secondary endpoints included disease control rate (DCR) and PFS. Tumors were analyzed using Myriad BRACAnalysis CDx and myChoice HRD assays; HRD-positive tumors were defined using a genomic instability score of ≥42.

RESULTS

Of 272 enrolled patients, 271 received olaparib and 270 were included in efficacy analyses. At data cut-off, ORRs in the gBRCAm, sBRCAm, HRD-positive, and HRD-negative cohorts were 69.3%, 64.0%, 29.4%, and 10.1%, respectively. DCRs were 96.0%, 100.0%, 79.4%, and 75.3% in each cohort, respectively. Median PFS was 11.0, 10.8, 7.2, and 5.4 months, respectively. The most common (≥ 20%) treatment-emergent adverse events included nausea, fatigue/asthenia, vomiting, anemia, constipation, diarrhea, and decreased appetite.

CONCLUSIONS

Olaparib treatment demonstrated activity across all cohorts. The greatest efficacy was observed in the BRCAm cohorts, regardless of gBRCAm/sBRCAm. For patients without a BRCAm, greater efficacy was observed in the HRD-positive than the HRD-negative cohorts. The safety profile was consistent with that established in previous olaparib studies.

A Pan-Canadian Consensus Statement on First-Line PARP Inhibitor Maintenance for Advanced, High-Grade Serous and Endometrioid Tubal, Ovarian, and Primary Peritoneal Cancers

The majority of patients with advanced, high-grade epithelial-tubo ovarian cancer (EOC) respond well to initial treatment with platinum-based chemotherapy; however, up to 80% of patients will experience a recurrence. Poly(ADP-ribose) Polymerase (PARP) inhibitors have been established as a standard of care maintenance therapy to prolong remission and prevent relapse following a response to first-line platinum-chemotherapy. Olaparib and niraparib are the PARP inhibitors currently approved for use in the first-line maintenance setting in Canada. Selection of maintenance therapy requires consideration of patient and tumour factors, presence of germline and somatic mutations, expected drug toxicity profile, and treatment access. This paper discusses the current clinical evidence for first-line PARP inhibitor maintenance therapy in patients with advanced, high-grade EOC and presents consensus statements and a treatment algorithm to aid Canadian oncologists on the selection and use of PARP inhibitors within the Canadian EOC treatment landscape.

Case Review: Whole-Exome Sequencing Analyses Identify Carriers of a Known Likely Pathogenic Intronic BRCA1 Variant in Ovarian Cancer Cases Clinically Negative for Pathogenic BRCA1 and BRCA2 Variants

Background: Detecting pathogenic intronic variants resulting in aberrant splicing remains a challenge in routine genetic testing. We describe germline whole-exome sequencing (WES) analyses and apply in silico predictive tools of familial ovarian cancer (OC) cases reported clinically negative for pathogenic BRCA1 and BRCA2 variants. Methods: WES data from 27 familial OC cases reported clinically negative for pathogenic BRCA1 and BRCA2 variants and 53 sporadic early-onset OC cases were analyzed for pathogenic variants in BRCA1 or BRCA2. WES data from carriers of pathogenic BRCA1 or BRCA2 variants were analyzed for pathogenic variants in 10 other OC predisposing genes. Loss of heterozygosity analysis was performed on tumor DNA from variant carriers. Results: BRCA1 c.5407-25T>A intronic variant, identified in two affected sisters and one sporadic OC case, is predicted to create a new splice effecting transcription of BRCA1. WES data from BRCA1 c.5407-25T>A carriers showed no evidence of pathogenic variants in other OC predisposing genes. Sequencing the tumor DNA from the variant carrier showed complete loss of the wild-type allele. Conclusions: The findings support BRCA1 c.5407-25T>A as a likely pathogenic variant and highlight the importance of investigating intronic sequences as causal variants in OC families where the involvement of BRCA1 is highly suggestive.

A functionally impaired missense variant identified in French Canadian families implicates FANCI as a candidate ovarian cancer-predisposing gene

Background

Familial ovarian cancer (OC) cases not harbouring pathogenic variants in either of the BRCA1 and BRCA2 OC-predisposing genes, which function in homologous recombination (HR) of DNA, could involve pathogenic variants in other DNA repair pathway genes.

Methods

Whole exome sequencing was used to identify rare variants in HR genes in a BRCA1 and BRCA2 pathogenic variant negative OC family of French Canadian (FC) ancestry, a population exhibiting genetic drift. OC cases and cancer-free individuals from FC and non-FC populations were investigated for carrier frequency of FANCI c.1813C>T; p.L605F, the top-ranking candidate. Gene and protein expression were investigated in cancer cell lines and tissue microarrays, respectively.

Results

In FC subjects, c.1813C>T was more common in familial (7.1%, 3/42) than sporadic (1.6%, 7/439) OC cases (P = 0.048). Carriers were detected in 2.5% (74/2950) of cancer-free females though female/male carriers were more likely to have a first-degree relative with OC (121/5249, 2.3%; Spearman correlation = 0.037; P = 0.011), suggesting a role in risk. Many of the cancer-free females had host factors known to reduce risk to OC which could influence cancer risk in this population. There was an increased carrier frequency of FANCI c.1813C>T in BRCA1 and BRCA2 pathogenic variant negative OC families, when including the discovery family, compared to cancer-free females (3/23, 13%; OR = 5.8; 95%CI = 1.7–19; P = 0.005). In non-FC subjects, 10 candidate FANCI variants were identified in 4.1% (21/516) of Australian OC cases negative for pathogenic variants in BRCA1 and BRCA2, including 10 carriers of FANCI c.1813C>T. Candidate variants were significantly more common in familial OC than in sporadic OC (P = 0.04). Localization of FANCD2, part of the FANCI-FANCD2 (ID2) binding complex in the Fanconi anaemia (FA) pathway, to sites of induced DNA damage was severely impeded in cells expressing the p.L605F isoform. This isoform was expressed at a reduced level, destabilized by DNA damaging agent treatment in both HeLa and OC cell lines, and exhibited sensitivity to cisplatin but not to a poly (ADP-ribose) polymerase inhibitor. By tissue microarray analyses, FANCI protein was consistently expressed in fallopian tube epithelial cells and only expressed at low-to-moderate levels in 88% (83/94) of OC samples.

Conclusions

This is the first study to describe candidate OC variants in FANCI, a member of the ID2 complex of the FA DNA repair pathway. Our data suggest that pathogenic FANCI variants may modify OC risk in cancer families.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13073-021-00998-5.

Radiotherapy Versus Inguinofemoral Lymphadenectomy as Treatment for Vulvar Cancer Patients With Micrometastases in the Sentinel Node: Results of GROINSS-V II

PURPOSE

The Groningen International Study on Sentinel nodes in Vulvar cancer (GROINSS-V)-II investigated whether inguinofemoral radiotherapy is a safe alternative to inguinofemoral lymphadenectomy (IFL) in vulvar cancer patients with a metastatic sentinel node (SN).

METHODS

GROINSS-V-II was a prospective multicenter phase-II single-arm treatment trial, including patients with early-stage vulvar cancer (diameter < 4 cm) without signs of lymph node involvement at imaging, who had primary surgical treatment (local excision with SN biopsy). Where the SN was involved (metastasis of any size), inguinofemoral radiotherapy was given (50 Gy). The primary end point was isolated groin recurrence rate at 24 months. Stopping rules were defined for the occurrence of groin recurrences.

RESULTS

From December 2005 until October 2016, 1,535 eligible patients were registered. The SN showed metastasis in 322 (21.0%) patients. In June 2010, with 91 SN-positive patients included, the stopping rule was activated because the isolated groin recurrence rate in this group went above our predefined threshold. Among 10 patients with an isolated groin recurrence, nine had SN metastases > 2 mm and/or extracapsular spread. The protocol was amended so that those with SN macrometastases (> 2 mm) underwent standard of care (IFL), whereas patients with SN micrometastases (≤ 2 mm) continued to receive inguinofemoral radiotherapy. Among 160 patients with SN micrometastases, 126 received inguinofemoral radiotherapy, with an ipsilateral isolated groin recurrence rate at 2 years of 1.6%. Among 162 patients with SN macrometastases, the isolated groin recurrence rate at 2 years was 22% in those who underwent radiotherapy, and 6.9% in those who underwent IFL (P = .011). Treatment-related morbidity after radiotherapy was less frequent compared with IFL.

CONCLUSION

Inguinofemoral radiotherapy is a safe alternative for IFL in patients with SN micrometastases, with minimal morbidity. For patients with SN macrometastasis, radiotherapy with a total dose of 50 Gy resulted in more isolated groin recurrences compared with IFL.

NR1D1 regulation by Ran GTPase via miR4472 identifies an essential vulnerability linked to aneuploidy in ovarian cancer

While aneuploidy is a main enabling characteristic of cancers, it also creates specific vulnerabilities. Here we demonstrate that Ran inhibition targets epithelial ovarian cancer (EOC) survival through its characteristic aneuploidy. We show that induction of aneuploidy in rare diploid EOC cell lines or normal cells renders them highly dependent on Ran. We also establish an inverse correlation between Ran and the tumor suppressor NR1D1 and reveal the critical role of Ran/NR1D1 axis in aneuploidy-associated endogenous DNA damage repair. Mechanistically, we show that Ran, through the maturation of miR4472, destabilizes the mRNA of NR1D1 impacting several DNA repair pathways. We showed that NR1D1 interacts with both PARP1 and BRCA1 leading to the inhibition of DNA repair. Concordantly, loss of Ran was associated with NR1D1 induction, accumulation of DNA damages, and lethality of aneuploid EOC cells. Our findings suggest a synthetic lethal strategy targeting aneuploid cells based on their dependency to Ran.

353 Identification of potential response predictors to maveropepimut-S (DPX-Survivac), a novel T cell activating immunotherapy, in patients with advanced recurrent ovarian cancer

Background

Epithelial ovarian cancer (OvCa) is the most lethal of gynecological malignancies. The high mortality is related to a late diagnosis with over 75% being at an advanced stage, high recurrence rates, and ultimately resistance to chemotherapy. Previous studies have consistently demonstrated a strong association between higher tumor T cell infiltration and improved survival in OvCa patients supporting the potential clinical utility of T cell activating immunotherapy approaches. Maveropepimut-S (MVP-S, formerly named DPX-Survivac) is a T cell activating immunotherapy which is a formulation of the proprietary drug delivery platform DPX™ with immunogenic T-cell epitopes derived from the tumor-associated antigen survivin. MVP-S in combination with intermittent low-dose cyclophosphamide has been shown to induce robust and durable antigen-specific T cell responses and anti-tumor clinical activity in recurrent OvCa patients. The current study presents translational data aimed at identifying tumor tissue-based predictive biomarkers for response to treatment with MVP-S.

Methods

Baseline and on-treatment tumor biopsies were collected from patients treated with MVP-S primed with immune-modulating low dose cyclophosphamide. Multiplex-immunohistochemistry (mIHC, Akoya Biosciences) and RNAseq analyses (Personalis Inc.) were used to analyze the tumor immune environment and identify potential response predictors to MVP-S.

Results

Twenty-two patients with advanced, recurrent OvCa were enrolled in this study. mIHC analysis demonstrated that higher baseline CD3+CD8+ T cell infiltration in tumor tissue was significantly associated with anti-tumor clinical activity of MVP-S defined as >10% on-treatment tumor regression. Pathway enrichment analyses using the differentially expressed genes associated with anti-tumor clinical activity confirmed these findings. In addition, we identified B cell pathway genes to be significantly upregulated in patients with >10% on-treatment tumor regression. mIHC analyses of paired biopsies available for one subject with clinical response (PR) demonstrated that MVP-S treatment induced increased T and B cell infiltration in the on-treatment biopsy compared to the baseline biopsy. These findings suggest that immunogenic tumors are more susceptible to the MVP-S treatment, in line with its mechanism of action. Pathway enrichment analyses further revealed that upregulation of genes or pathways related to immune-suppression (e.g. WNT pathway) or immune evasion/exclusion (CD276, Arg2) were significantly associated with lack of anti-tumor activity indicative of potential mechanism of primary resistance.

Conclusions

Collectively, these results provide insight for possible response predictors to MVP-S based therapy

Trial Registration

NCT02785250

Ethics Approval

The protocol and patient-informed consent form received approval by Institutional Review Boards. Written informed consent was obtained from all patients. REBs: Comite d’ethique de la recherche du CHUM (Montreal, Canada); Western Institutional Review Board 20161075 (Augusta, GA, USA); FWA #00002505 (NEW YORK, NY, USA); FWA00000161, IRB00000471 (Portland, Oregon, USA); University Health Network REB (Toronto, Canada); FWA00000935, FWA00000934 (Standford, CA, USA); Health Research Ethics Board of Alberta, (Edmonton, Canada)

Characterization of patients with long-term responses to rucaparib treatment in recurrent ovarian cancer

OBJECTIVE

To describe molecular and clinical characteristics of patients with high-grade recurrent ovarian carcinoma (HGOC) who had long-term responses to the poly(ADP-ribose) polymerase (PARP) inhibitor rucaparib.

METHODS

This post hoc analysis pooled patients from Study 10 (NCT01482715; Parts 2A and 2B; n = 54) and ARIEL2 (NCT01891344; Parts 1 and 2; n = 491). Patients with investigator-assessed complete or partial response per RECIST were classified based on duration of response (DOR): long (≥1 year), intermediate (6 months to <1 year), or short (<6 months). Next-generation sequencing was used to detect deleterious mutations and loss of heterozygosity (LOH) in tumors.

RESULTS

Overall, 25.3% (138/545) of enrolled patients were responders. Of these, 27.5% (38/138) had long-term responses; 28.3% (39/138) were intermediate- and 34.8% (48/138) were short-term responders. Most of the long-term responders harbored a BRCA1 or BRCA2 (BRCA) mutation (71.1%, 27/38), and BRCA structural variants were most frequent among long-term responders (14.8%; 4/27). Responders with HGOC harboring a BRCA structural variant (n = 5) had significantly longer DOR than patients with other mutation types (n = 81; median not reached vs 0.62 years; HR, 0.21; 95% CI, 0.10-0.43; unadjusted p = 0.014). Among responders with BRCA wild-type HGOC, most long- and intermediate-term responders had high genome-wide LOH: 81.8% (9/11) and 76.9% (10/13), respectively, including 7 with deleterious RAD51C, RAD51D, or CDK12 mutations.

CONCLUSION

Among patients who responded to rucaparib, a substantial proportion achieved responses lasting ≥1 year. These analyses demonstrate the relationship between DOR to PARP inhibitor treatment and molecular characteristics in HGOC, such as presence of reversion-resistant BRCA structural variants.

SATB2 Expression in Uterine Sarcoma: A Multicenter Retrospective Study

Uterine sarcomas represent a clinical challenge because of their difficult diagnosis and the poor prognosis of certain subtypes. The aim of this study was to evaluate the expression of the special AT-rich sequence-binding protein 2 (SATB2) in endometrial stromal sarcoma (ESS) and other types of uterine sarcoma by immunohistochemistry. We studied the expression of SATB2 on 71 full tissue sections of endometrial stromal nodule, low-grade ESS, uterine leiomyomas and leiomyosarcoma, undifferentiated uterine sarcoma, adenosarcoma, and carcinosarcoma samples. Nuclear SATB2 expression was then evaluated in an extended sample set using a tissue microarray, including 78 additional uterine tumor samples. Overall, with a cut-off of ≥10% of tumor cell staining as positive, the nuclear SATB2 score was negative in all endometrial stromal nodule samples (n=10) and positive in 83% of low-grade ESS samples (n=29/35), 40% of undifferentiated uterine sarcoma (n=4/10), 13% of leiomyosarcoma (n=2/16), 14% of adenosarcoma (n=3/22), and 8% carcinosarcoma (n=2/25) samples. Furthermore, in ESS patients, direct comparison of nuclear SATB2 scores with clinicopathologic parameters and other reported biomarkers such as progesterone receptor and estrogen receptor showed that nuclear SATB2 was associated with PR expression and a decreased risk of disease-specific death (odds ratio=0.06, 95% confidence interval=0.04-0.81, P=0.04). Our data suggest that SATB2 could be a marker with relative sensitivity (83%) for distinguishing between endometrial stromal nodule and ESS with potential prognostic value.

Abstract 2056: The genomic landscape of carriers of rare variants in FANCI, a new candidate ovarian cancer predisposing gene

The potentially pathogenic variant (PPV), FANCI c.1813C&gt;T; p.L605F, in a new candidate ovarian cancer (OC) predisposing gene was discovered by whole exome sequencing (WES) of familial OC cases from the founder French Canadian (FC) population for discovering new OC predisposing genes. Modeling this variant in cellulo suggested this variant encodes an unstable protein. FANCI is an essential member upstream of the homologous recombination DNA repair pathway and intersects BRCA1 and BRCA2 function, proteins encoded by genes involved in hereditary OC. Investigating the FC founder population facilitates the discovery of PPVs as they are more likely to harbor recurrent variants due to common ancestors, increasing the likelihood of identifying candidate genes in cancer families.

To further support the candidacy of FANCI as a new OC predisposing gene, we investigated the germline landscape of c.1813C&gt;T carrier FC OC cases for co-occurring PPVs in known or proposed new (emerging) OC predisposing genes or other genes involved in similar pathways (DNA repair).

Using WES of peripheral blood lymphocyte DNA, the genomic landscape of 10 FANCI carriers were investigated for heterozygous PPVs in 276 DNA repair pathways genes, which included known (BRCA1, BRCA2, MSH2, MLH1, MSH6, PMS2) and emerging (BRIP1, RAD51C, RAD51D) OC predisposing genes. Top ranking candidate variants (minor allele frequency &lt;1%) were identified using 11 different in silico tools that assessed amino acid conversation or potential pathogenicity. Pathogenicity of known and emerging OC predisposing genes was assessed using BRCAExchange (www.brcaexchange.org) and ClinVar (www.ncbi.nlm.nih.gov/clinvar/). A similar analysis was done with WES data from 13 FC OC cases harboring pathogenic BRCA1/BRCA2 variants.

We identified 31 variants in 27 genes in FANCI c.1813C&gt;T carriers. A previously known carrier of a pathogenic BRCA1 variant (c.2836_2837del; p.Ile946GlnfsTer5) was also identified in a familial case. No carriers of other pathogenic variants in known or emerging OC predisposing genes were found. However, FANCI carriers were found to carry at least one other PPV in a DNA repair pathway gene (range 2-9; average=4.1). There were no other carriers of variants in common among all OC cases, though at least 2 cases carried a variant in the same gene. FC OC cases harboring BRCA1/BRCA2 variants carried at least one other PPV in a DNA repair pathway gene (range 2-7; average 4).

It is possible that the identified variants influence or modify risk in conjunction with FANCI, though no PPV was identified in all carriers. As new cancer predisposing genes are identified it will become increasingly important to characterize the genetic context in which variants are identified. This will allow for further insight to clinical translatability once penetrance has been established.

Citation Format: Caitlin Fierheller, Wejdan M Alenezi, Corinne Serruya, Timothée Revil, Javad Nadaf, Anne-Marie Mes-Masson, Diane Provencher, William D Foulkes, Zaki El Haffaf, Celia M T Greenwood, Jean-Yves Masson, Jiannis Ragoussis, Patricia N Tonin. The genomic landscape of carriers of rare variants in FANCI, a new candidate ovarian cancer predisposing gene [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2056.

Population exposure-efficacy and exposure-safety analyses for rucaparib in patients with recurrent ovarian carcinoma from Study 10 and ARIEL2

OBJECTIVE

To evaluate correlations between rucaparib exposure and selected efficacy and safety endpoints in patients with recurrent ovarian carcinoma using pooled data from Study 10 and ARIEL2.

METHODS

Efficacy analyses were limited to patients with carcinomas harboring a deleterious BRCA1 or BRCA2 mutation who had received ≥2 prior lines of chemotherapy. Safety was evaluated in all patients who received ≥1 rucaparib dose. Steady-state daily area under the concentration-time curve (AUCss) and maximum concentration (Cmax,ss) for rucaparib were calculated for each patient and averaged by actual dose received over time (AUCavg,ss and Cmax,avg,ss) using a previously developed population pharmacokinetic model.

RESULTS

Rucaparib exposure was dose-proportional and not associated with baseline patient weight. In the exposure-efficacy analyses (n = 121), AUCavg,ss was positively associated with independent radiology review-assessed RECIST response in the subgroup of patients with platinum-sensitive recurrent disease (n = 75, p = 0.017). In the exposure-safety analyses (n = 393, 40 mg once daily to 840 mg twice daily [BID] starting doses), most patients received a 600 mg BID rucaparib starting dose, with 27% and 21% receiving 1 or ≥2 dose reductions, respectively. Cmax,ss was significantly correlated with grade ≥2 serum creatinine increase, grade ≥3 alanine transaminase/aspartate transaminase increase, platelet decrease, fatigue/asthenia, and maximal hemoglobin decrease (p < 0.05).

CONCLUSION

The exposure-response analyses provide support for the approved starting dose of rucaparib 600 mg BID for maximum clinical benefit with subsequent dose modification only following the occurrence of a treatment-emergent adverse event in patients with BRCA-mutated recurrent ovarian carcinoma.

Molecular and clinical determinants of response and resistance to rucaparib for recurrent ovarian cancer treatment in ARIEL2 (Parts 1 and 2)

ARIEL2 (NCT01891344) is a single-arm, open-label phase 2 study of the PARP inhibitor (PARPi) rucaparib in relapsed high-grade ovarian carcinoma. In this post hoc exploratory biomarker analysis of pre- and post-platinum ARIEL2 samples, RAD51C and RAD51D mutations and high-level BRCA1 promoter methylation predict response to rucaparib, similar to BRCA1/BRCA2 mutations. BRCA1 methylation loss may be a major cross-resistance mechanism to platinum and PARPi. Genomic scars associated with homologous recombination deficiency are irreversible, persisting even as platinum resistance develops, and therefore are predictive of rucaparib response only in platinum-sensitive disease. The RAS, AKT, and cell cycle pathways may be additional modulators of PARPi sensitivity.

High-dimensional analysis of the adenosine pathway in high-grade serous ovarian cancer

BACKGROUND

Hydrolysis of extracellular ATP to adenosine (eADO) is an important immune checkpoint in cancer immunology. We here investigated the impact of the eADO pathway in high-grade serous ovarian cancer (HGSC) using multiparametric platforms.

METHODS

We performed a transcriptomic meta-analysis of eADO-producing CD39 and CD73, an eADO signaling gene signature, immune gene signatures and clinical outcomes in approximately 1200 patients with HGSC. Protein expression, localization and prognostic impact of CD39, CD73 and CD8 were then performed on approximately 1000 cases on tissue microarray, and tumor-infiltrating lymphocytes (TILs) were analyzed by flow cytometry and single-cell RNA sequencing on a subset of patients.

RESULTS

Concomitant CD39 and CD73 gene expression, as well as high levels of an eADO gene signature, were associated with worse prognosis in patients with HGSC, notably in the immunoregulatory molecular subtype, characterized by an immune-active microenvironment. CD39 was further associated with primary chemorefractory and chemoresistant human HGSC and platinum-based chemotherapy of murine HGSC was significantly more effective in CD39-deficient mice. At protein level, CD39 and CD73 were predominantly expressed by cancer-associated fibroblasts, and CD39 was expressed on severely exhausted, clonally expanded and putative tissue-resident memory TILs.

CONCLUSIONS

Our study revealed the clinical, immunological, subtype-specific impacts of eADO signaling in HGSC, unveiled the chemoprotective effect of CD39 and supports the evaluation of eADO-targeting agents in patients with ovarian cancer.

Tubulosquamous Polyp of the Vagina: Misplaced Skene's Glands Analogous to the Male Prostate

Tubulosquamous polyp (TSP) of the vagina is a rare and benign lesion, best considered along the spectrum of lesions derived from Skene's glands, the female counterpart of male prostatic glands. It is likely underdiagnosed and represents a challenging diagnosis if one is unfamiliar with this entity. We present an illustrative case of TSP occurring as an upper vaginal wall nodule of a 75-year-old woman, with characteristic morphology and broad immunophenotype. It should be suspected in postmenopausal women with a polyp that demonstrates biphasic squamous and glandular components, which show a prostatic immunophenotype.

Investigating the causal role of MRE11A p.E506* in breast and ovarian cancer

The nuclease MRE11A is often included in genetic test panels for hereditary breast and ovarian cancer (HBOC) due to its BRCA1-related molecular function in the DNA repair pathway. However, whether MRE11A is a true predisposition gene for HBOC is still questionable. We determined to investigate this notion by dissecting the molecular genetics of the c.1516G > T;p.E506* truncating MRE11A variant, that we pinpointed in two unrelated French-Canadian (FC) HBOC patients. We performed a case–control study for the variant in ~ 2500 breast, ovarian, and endometrial cancer patients from the founder FC population of Quebec. Furthermore, we looked for the presence of second somatic alterations in the MRE11A gene in the tumors of the carriers. In summary, these investigations suggested that the identified variant is not associated with an increased risk of developing breast or ovarian cancer. We finally performed a systematic review for all the previously reported MRE11A variants in breast and ovarian cancer. We found that MRE11A germline variants annotated as pathogenic on ClinVar often lacked evidence for such classification, hence misleading the clinical management for affected patients. In summary, our report suggests the lack of clinical utility of MRE11A testing in HBOC, at least in the White/Caucasian populations.

Carboplatin sensitivity in epithelial ovarian cancer cell lines: The impact of model systems

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy in North America, underscoring the need for the development of new therapeutic strategies for the management of this disease. Although many drugs are pre-clinically tested every year, only a few are selected to be evaluated in clinical trials, and only a small number of these are successfully incorporated into standard care. Inaccuracies with the initial in vitro drug testing may be responsible for some of these failures. Drug testing is often performed using 2D monolayer cultures or 3D spheroid models. Here, we investigate the impact that these different in vitro models have on the carboplatin response of four EOC cell lines, and in particular how different 3D models (polydimethylsiloxane-based microfluidic chips and ultra low attachment plates) influence drug sensitivity within the same cell line. Our results show that carboplatin responses were observed in both the 3D spheroid models tested using apoptosis/cell death markers by flow cytometry. Contrary to previously reported observations, these were not associated with a significant decrease in spheroid size. For the majority of the EOC cell lines (3 out of 4) a similar carboplatin response was observed when comparing both spheroid methods. Interestingly, two cell lines classified as resistant to carboplatin in 2D cultures became sensitive in the 3D models, and one sensitive cell line in 2D culture showed resistance in 3D spheroids. Our results highlight the challenges of choosing the appropriate pre-clinical models for drug testing.

Genomic analysis of low-grade serous ovarian carcinoma to identify key drivers and therapeutic vulnerabilities

Low-grade serous ovarian carcinoma (LGSOC) is associated with a poor response to existing chemotherapy, highlighting the need to perform comprehensive genomic analysis and identify new therapeutic vulnerabilities. The data presented here represent the largest genetic study of LGSOCs to date (n = 71), analysing 127 candidate genes derived from whole exome sequencing cohorts to generate mutation and copy-number variation data. Additionally, immunohistochemistry was performed on our LGSOC cohort assessing oestrogen receptor, progesterone receptor, TP53, and CDKN2A status. Targeted sequencing identified 47% of cases with mutations in key RAS/RAF pathway genes (KRAS, BRAF, and NRAS), as well as mutations in putative novel driver genes including USP9X (27%), MACF1 (11%), ARID1A (9%), NF2 (4%), DOT1L (6%), and ASH1L (4%). Immunohistochemistry evaluation revealed frequent oestrogen/progesterone receptor positivity (85%), along with CDKN2A protein loss (10%) and CDKN2A protein overexpression (6%), which were linked to shorter disease outcomes. Indeed, 90% of LGSOC samples harboured at least one potentially actionable alteration, which in 19/71 (27%) cases were predictive of clinical benefit from a standard treatment, either in another cancer's indication or in LGSOC specifically. In addition, we validated ubiquitin-specific protease 9X (USP9X), which is a chromosome X-linked substrate-specific deubiquitinase and tumour suppressor, as a relevant therapeutic target for LGSOC. Our comprehensive genomic study highlighted that there is an addiction to a limited number of unique 'driver' aberrations that could be translated into improved therapeutic paths. © 2020 The Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Abstract 5833: Senescence is a central response to chemotherapy in ovarian cancer

High-grade serous ovarian carcinoma (HGSOC) commonly responds to initial therapy, but this response is rarely durable. Understanding the cell fate decisions taken by HGSOC cells in response to treatment could guide new therapeutic opportunities. Here, we find that more than 90% of tissue-derived primary HGSOC cultures, reflecting the original disease, retain the capacity to undergo stress-induced cellular senescence and primarily undergo therapy-induced senescence (TIS) in response to first-line carboplatin/taxol chemotherapy. HGSOC-TIS displays senescence-associated hallmarks, including a stable proliferation arrest, increased p16INK4A expression, persistent DNA damage, an inflammatory secretome, and senolytic sensitivity, suggesting new avenues for selective pharmacological manipulation of these cells. Comparison of pre- and post-chemotherapy patient HGSOC tissue samples revealed changes in physio-pathological senescence biomarkers supporting the occurrence of post-treatment TIS. Whether cell senescence induced by cancer therapy is beneficial or detrimental to treatment outcomes remains unknown. We find that patients with stronger TIS biomarkers in post-chemotherapy tissues have a more favorale 5-year survival, suggesting that the induction of senescence in HGSOC cells accounts, at least in part, for beneficial responses to treatment. Given that HGSOC cells almost universally retain the capacity to undergo senescence and that senescence appears beneficial in this context, senescence-centric therapeutic avenues should be further explored.

Citation Format: Michael Skulimowski, Llilians Calvo-Gonzales, Shuofei Cheng, Isabelle Clément, Lise Portelance, Yu Zhan, Euridice Carmona, Manon de Ladurantaye, Julie Lafontaine, Kurosh Rahimi, Diane Provencher, Anne-Marie Mes-Masson, Francis Rodier. Senescence is a central response to chemotherapy in ovarian cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5833.

Ran GTPase: A Key Player in Tumor Progression and Metastasis

Ran (Ras-related nuclear protein) GTPase is a member of the Ras superfamily. Like all the GTPases, Ran cycles between an active (GTP-bound) and inactive (GDP-bound) state. However, Ran lacks the CAAX motif at its C-terminus, a feature of other small GTPases that ensures a plasma membrane localization, and largely traffics between the nucleus and the cytoplasm. Ran regulates nucleo-cytoplasmic transport of molecules through the nuclear pore complex and controls cell cycle progression through the regulation of microtubule polymerization and mitotic spindle formation. The disruption of Ran expression has been linked to cancer at different levels - from cancer initiation to metastasis. In the present review, we discuss the contribution of Ran in the acquisition of three hallmarks of cancer, namely, proliferative signaling, resistance to apoptosis, and invasion/metastasis, and highlight its prognostic value in cancer patients. In addition, we discuss the use of this GTPase as a therapeutic target in cancer.

Low-grade serous carcinoma (LGSC): A Canadian multicenter review of practice patterns and patient outcomes

OBJECTIVE

Patients with advanced low-grade serous carcinoma (LGSC) have poor long-term survival rates. As a rare histotype, there are uncertainties regarding the use of current therapies. Thus, we studied practice patterns and treatment outcomes as part of a national initiative to better understand and improve the care of women with advanced LGSC.

METHODS

This retrospective cohort study was conducted in 5 Canadian referral institutions from 2000 to 2016. Data collection and pathology reporting were standardized. Outcome measures included overall survival (OS), progression-free survival (PFS), progression-free intervals (PFI), and time to next treatment (TTNT). Cox regression analysis was used to evaluate the effects of clinical and pathologic factors on outcomes and prognosis.

RESULTS

There were 134 patients (stage II-IV) with a median follow-up of 32.4 months (range 1.6-228). Four primary treatments were compared across institutions: 1) surgery followed by chemotherapy (56%), 2) neoadjuvant chemotherapy (NACT) followed by surgery (27%), 3) surgery alone (9%), and 4) surgery followed by anti-hormone therapy (4%). Primary platinum/paclitaxel chemotherapy was used in 81%. Patients treated with NACT had worse PFS. Multivariable Cox regression analysis identified lesser residual disease, younger age, and primary peritoneal origin as variables significantly associated with better OS/PFS (p < 0.03). One institution had significantly better PFS than the others (p = 0.025), but this finding could be related to a higher frequency of primary peritoneal LGSC. PFI and TTNT intervals in patients with relapsed disease were not significantly different after the first relapse irrespective of treatment type.

CONCLUSIONS

There are notable differences in practice patterns across Canada. This underscores the need for ongoing strategies to measure, evaluate and achieve optimal patient outcomes for women with advanced LGSC.

Hormone receptor expression and outcomes in low-grade serous ovarian carcinoma

OBJECTIVE

Low-grade serous ovarian carcinomas (LGSC) are frequently ER/PR positive, though the mechanisms by which ER/PR regulate prognosis or anti-estrogen treatment efficacy are poorly understood. We studied ER/PR expression in LGSC tumors and cell lines to evaluate patient outcomes and cellular treatment responses.

METHODS

LGSC tumors and patient-derived cell lines were studied from patients with advanced-stage (III/IV) disease. Tumor samples and clinical data were obtained from the Canadian Ovarian Experimental Unified Resource (COEUR-tissue microarray) and the Ovarian Cancer Research (OvCaRe) tissue bank. ER/PR expression was assessed by both Western blot and immunohistochemistry (IHC). Two different IHC scoring systems (simple and Allred) were used. Cox regression was used to identify factors (age, disease residuum, ER/PR status, etc.) associated with progression-free (PFS) and overall survival (OS). Estradiol and tamoxifen proliferation and viability experiments were performed in LGSC cell lines.

RESULTS

In 55 LGSC cases studied, median follow-up was 56 months (range 1-227). Fifty-three (96%) cases strongly expressed ER whereas 37 (67%) expressed PR. Cox-regression analysis showed that residuum (p < 0.001) was significantly associated with PFS, whereas both ER Allred score (p = 0.005) and residuum (p = 0.004) were significant for OS. None of the LGSC cell lines expressed PR. Loss of PR and ER expression over time was detected in LGSC tumors and cell lines respectively. Estrogen and tamoxifen treatment did not alter LGSC cell proliferation or viability in-vitro.

CONCLUSIONS

In patients with advanced LGSC, higher ER Allred scores were significantly associated with better overall survival. ER/PR expression changed over time in both LGSC tumors and cell lines. Better translational research models are needed to elucidate the molecular mechanisms of ER/PR signalling in LGSC.

Clinicopathological features of women with epithelial ovarian cancer and double heterozygosity for BRCA1 and BRCA2: A systematic review and case report analysis

BACKGROUND

Carriers of pathogenic variants in both BRCA1 and BRCA2 genes as a double mutation (BRCA1/2 DM) have been rarely reported in women with epithelial ovarian cancer (EOC).

METHODS

We reviewed the English literature and interrogated three repositories reporting EOC patients carrying BRCA1/2 DM. The clinicopathological parameters of 36 EOC patients carrying germline BRCA1/2 DM were compared to high-grade serous EOC women of the COEUR cohort with known germline BRCA1/BRCA2 mutation carrier status (n = 376 non-carriers, n = 65 BRCA1 and n = 38 BRCA2). Clinicopathological parameters evaluated were age at diagnosis, stage of disease, loss of heterozygosity, type of mutation, immunohistochemistry profile, progression occurrence and survival.

RESULTS

Median age at diagnosis of BRCA1/2 DM patients was 51.9 years, similar to BRCA1 mutation carriers (49.7 years, p = .58) and younger than BRCA2 mutation carriers (58.1 years, p = .02). Most patients were diagnosed at advanced stage (III-IV; 82%) and were carriers of founder/frequent mutations (69%). Tissue immunostainings revealed no progesterone receptor expression and low intraepithelial inflammation. The 5-year survival rate (60%) was significantly lower than that of BRCA2 mutation carriers (76%, p = .03) but not of BRCA1 mutation carriers (51%, p = .37).

CONCLUSIONS

Our data suggests some co-dominant effect of both mutations but the outcome of these patients more closely resembled that of BRCA1 mutation carriers with poor prognosis factors.

Exploring the Clinical Impact of Predictive Biomarkers in Serous Ovarian Carcinomas

Epithelial ovarian cancer (EOC) is the most lethal gynecologic malignancy. Although initial response rates to standard platinum-based treatment are at 70-80%, long-term response in advanced EOC disease is rarely achieved with the development of chemoresistance and recurrence, contributing to overall survival rates below 45%. Additional challenges stem from EOC heterogeneity, reflecting at least five histological subtypes, each with different underlying molecular characteristics and clinicopathology that have significant implications in treatment effectiveness and management. Since the last decade, technologies in genomics, proteomics and pathology have been deployed to find reliable clinical markers that can identify patients sensitive to standard chemotherapy treatments and stratify patients for more suitable targeted therapies. These efforts have identified several molecular markers of prognostic value that have been validated as biomarkers, such as BRCA and KRAS mutations, or are currently under investigation in clinical trials, such as CD8 T cells, immune checkpoint inhibitors and progesterone receptor. Recent advancements in biomarker research have also revealed new targets that have expanded treatment options, introducing poly (ADP-ribose) polymerase (PARP) inhibitors, anti-angiogenic agents, inhibitors targeting signaling pathways, and immunotherapy to improve maintenance therapies or enhance first-line therapy. This review presents a summary of current biomarkers, in clinical use or under evaluation, demonstrating a potential to inform on patient selection for treatment efficacy and predict response to EOC therapies, with particular focus on the serous subtypes, including high-grade and low-grade serous carcinomas.

Adjuvant chemoradiotherapy versus radiotherapy alone in women with high-risk endometrial cancer (PORTEC-3): patterns of recurrence and post-hoc survival analysis of a randomised phase 3 trial

BACKGROUND

The PORTEC-3 trial investigated the benefit of combined adjuvant chemotherapy and radiotherapy versus pelvic radiotherapy alone for women with high-risk endometrial cancer. We updated the analysis to investigate patterns of recurrence and did a post-hoc survival analysis.

METHODS

In the multicentre randomised phase 3 PORTEC-3 trial, women with high-risk endometrial cancer were eligible if they had International Federation of Gynaecology and Obstetrics (FIGO) 2009 stage I, endometrioid grade 3 cancer with deep myometrial invasion or lymphovascular space invasion, or both; stage II or III disease; or stage I-III disease with serous or clear cell histology; were aged 18 years and older; and had a WHO performance status of 0-2. Participants were randomly assigned (1:1) to receive radiotherapy alone (48·6 Gy in 1·8 Gy fractions given on 5 days per week) or chemoradiotherapy (two cycles of cisplatin 50 mg/m² given intravenously during radiotherapy, followed by four cycles of carboplatin AUC5 and paclitaxel 175 mg/m² given intravenously), by use of a biased coin minimisation procedure with stratification for participating centre, lymphadenectomy, stage, and histological type. The co-primary endpoints were overall survival and failure-free survival. Secondary endpoints of vaginal, pelvic, and distant recurrence were analysed according to the first site of recurrence. Survival endpoints were analysed by intention-to-treat, and adjusted for stratification factors. Competing risk methods were used for failure-free survival and recurrence. We did a post-hoc analysis to analyse patterns of recurrence with 1 additional year of follow-up. The study was closed on Dec 20, 2013; follow-up is ongoing. This study is registered with ISRCTN, number ISRCTN14387080, and ClinicalTrials.gov, number NCT00411138.

FINDINGS

Between Nov 23, 2006, and Dec 20, 2013, 686 women were enrolled, of whom 660 were eligible and evaluable (330 in the chemoradiotherapy group, and 330 in the radiotherapy-alone group). At a median follow-up of 72·6 months (IQR 59·9-85·6), 5-year overall survival was 81·4% (95% CI 77·2-85·8) with chemoradiotherapy versus 76·1% (71·6-80·9) with radiotherapy alone (adjusted hazard ratio [HR] 0·70 [95% CI 0·51-0·97], p=0·034), and 5-year failure-free survival was 76·5% (95% CI 71·5-80·7) versus 69·1% (63·8-73·8; HR 0·70 [0·52-0·94], p=0·016). Distant metastases were the first site of recurrence in most patients with a relapse, occurring in 78 of 330 women (5-year probability 21·4%; 95% CI 17·3-26·3) in the chemoradiotherapy group versus 98 of 330 (5-year probability 29·1%; 24·4-34·3) in the radiotherapy-alone group (HR 0·74 [95% CI 0·55-0·99]; p=0·047). Isolated vaginal recurrence was the first site of recurrence in one patient (0·3%; 95% CI 0·0-2·1) in both groups (HR 0·99 [95% CI 0·06-15·90]; p=0·99), and isolated pelvic recurrence was the first site of recurrence in three women (0·9% [95% CI 0·3-2·8]) in the chemoradiotherapy group versus four (0·9% [95% CI 0·3-2·8]) in the radiotherapy-alone group (HR 0·75 [95% CI 0·17-3·33]; p=0·71). At 5 years, only one grade 4 adverse event (ileus or obstruction) was reported (in the chemoradiotherapy group). At 5 years, reported grade 3 adverse events did not differ significantly between the two groups, occurring in 16 (8%) of 201 women in the chemoradiotherapy group versus ten (5%) of 187 in the radiotherapy-alone group (p=0·24). The most common grade 3 adverse event was hypertension (in four [2%] women in both groups). At 5 years, grade 2 or worse adverse events were reported in 76 (38%) of 201 women in the chemoradiotherapy group versus 43 (23%) of 187 in the radiotherapy-alone group (p=0·002). Sensory neuropathy persisted more often after chemoradiotherapy than after radiotherapy alone, with 5-year rates of grade 2 or worse neuropathy of 6% (13 of 201 women) versus 0% (0 of 187). No treatment-related deaths were reported.

INTERPRETATION

This updated analysis shows significantly improved overall survival and failure-free survival with chemoradiotherapy versus radiotherapy alone. This treatment schedule should be discussed and recommended, especially for women with stage III or serous cancers, or both, as part of shared decision making between doctors and patients. Follow-up is ongoing to evaluate long-term survival.

FUNDING

Dutch Cancer Society, Cancer Research UK, National Health and Medical Research Council, Project Grant, Cancer Australia Grant, Italian Medicines Agency, and the Canadian Cancer Society Research Institute.

Dose-Ranging and Cohort-Expansion Study of Monalizumab (IPH2201) in Patients with Advanced Gynecologic Malignancies: A Trial of the Canadian Cancer Trials Group (CCTG): IND221

PURPOSE

Monalizumab binds CD94/NKG2A, preventing HLA-E inhibition of tumor lymphocytes. A dose-ranging/cohort expansion trial of monalizumab for recurrent gynecologic malignancies was conducted to determine the recommended phase II dose (RP2D) and to explore clinical activity, pharmacokinetics, pharmacodynamics, safety, and immunogenicity.

PATIENTS AND METHODS

Participants (and part 2 expansion cohorts) included (i) platinum-sensitive ovarian, (ii) platinum-resistant ovarian, (iii) squamous cervical (CX), and (iv) epithelial endometrial (END) carcinomas. Part 1 assessed monalizumab at 1, 4, or 10 mg/kg every 2 weeks. In part 2, ≥4 patients/cohort underwent pre- and on-treatment tumor biopsies. Preset criteria determined cohort expansion.

RESULTS

A total of 58 participants were evaluable. The RP2D was 10 mg/kg i.v. every 2 weeks. Dose proportionality and 100% NKG2A saturation were observed. Related adverse events were mild: headache, abdominal pain, fatigue, nausea, and vomiting. Grade 3 related adverse events were nausea (1), vomiting (1), dehydration (1), fatigue (2), anorexia (1), dyspnea (1), and proctitis (1). Dose-limiting toxicities were not observed. Hematologic and biochemical changes were mild and not dose related. Best response was SD: part 1, 7 of 18 (39%) [3.4 months (1.4-5.5)], and part 2, 7 of 39 (18%) [1.7 months (CX) to 14.8 months (END)]. Neither a predictive biomarker for SD nor evidence of pharmacodynamic effects was identified. There was a trend to significance between a reduction in lymphocyte HLA-E total score and pharmacodynamics.

CONCLUSIONS

Monalizumab 10 mg/kg i.v. every 2 week is well tolerated in patients with pretreated gynecologic cancers. Short-term disease stabilization was observed. Future studies should assess combinations with other agents, including immunotherapeutics.

Exploiting interconnected synthetic lethal interactions between PARP inhibition and cancer cell reversible senescence

Senescence is a tumor suppression mechanism defined by stable proliferation arrest. Here we demonstrate that the known synthetic lethal interaction between poly(ADP-ribose) polymerase 1 inhibitors (PARPi) and DNA repair triggers p53-independent ovarian cancer cell senescence defined by senescence-associated phenotypic hallmarks including DNA-SCARS, inflammatory secretome, Bcl-XL-mediated apoptosis resistance, and proliferation restriction via Chk2 and p21 (CDKN1A). The concept of senescence as irreversible remains controversial and here we show that PARPi-senescent cells re-initiate proliferation upon drug withdrawal, potentially explaining the requirement for sustained PARPi therapy in the clinic. Importantly, PARPi-induced senescence renders ovarian and breast cancer cells transiently susceptible to second-phase synthetic lethal approaches targeting the senescence state using senolytic drugs. The combination of PARPi and a senolytic is effective in preclinical models of ovarian and breast cancer suggesting that coupling these synthetic lethalities provides a rational approach to their clinical use and may together be more effective in limiting resistance.

Exploiting interconnected synthetic lethal interactions between PARP inhibition and cancer cell reversible senescence

Senescence is a tumor suppression mechanism defined by stable proliferation arrest. Here we demonstrate that the known synthetic lethal interaction between poly(ADP-ribose) polymerase 1 inhibitors (PARPi) and DNA repair triggers p53-independent ovarian cancer cell senescence defined by senescence-associated phenotypic hallmarks including DNA-SCARS, inflammatory secretome, Bcl-XL-mediated apoptosis resistance, and proliferation restriction via Chk2 and p21 (CDKN1A). The concept of senescence as irreversible remains controversial and here we show that PARPi-senescent cells re-initiate proliferation upon drug withdrawal, potentially explaining the requirement for sustained PARPi therapy in the clinic. Importantly, PARPi-induced senescence renders ovarian and breast cancer cells transiently susceptible to second-phase synthetic lethal approaches targeting the senescence state using senolytic drugs. The combination of PARPi and a senolytic is effective in preclinical models of ovarian and breast cancer suggesting that coupling these synthetic lethalities provides a rational approach to their clinical use and may together be more effective in limiting resistance.

Niraparib Maintenance Therapy in Patients With Recurrent Ovarian Cancer After a Partial Response to the Last Platinum-Based Chemotherapy in the ENGOT-OV16/NOVA Trial

PURPOSE

In the ENGOT-OV16/NOVA trial (ClinicalTrials.gov identifier: NCT01847274), maintenance therapy with niraparib, a poly(ADP-ribose) polymerase inhibitor, prolonged progression-free survival in patients with platinum-sensitive, recurrent ovarian cancer who had a response to their last platinum-based chemotherapy. The objective of the study was to assess the clinical benefit and patient-reported outcomes in patients who had a partial response (PR) and complete response (CR) to their last platinum-based therapy.

PATIENTS AND METHODS

A total of 553 patients were enrolled in the trial. Of 203 patients with a germline BRCA mutation (gBRCAmut), 99 had a PR and 104 had a CR to their last platinum-based therapy; of 350 patients without a confirmed gBRCAmut (non–gBRCAmut), 173 had a PR and 177 had a CR. Post hoc analyses were carried out to evaluate safety and the risk of progression in these patients according to gBRCAmut status and response to their last platinum-based therapy. Ovarian cancer–specific symptoms and quality of life were assessed using the Functional Assessment of Cancer Therapy–Ovarian Symptom Index.

RESULTS

Progression-free survival was improved in patients treated with niraparib compared with placebo in both the gBRCAmut cohort (PR: hazard ratio [HR], 0.24; 95% CI, 0.131 to 0.441; P < .0001; CR: HR, 0.30; 95% CI, 0.160 to 0.546; P < .0001) and the non–gBRCAmut cohort (PR: HR, 0.35; 95% CI, 0.230 to 0.532; P < .0001; CR: HR, 0.58; 95% CI, 0.383 to 0.868; P = .0082). The incidence of any-grade and grade 3 or greater adverse events was manageable. No meaningful differences were observed between niraparib and placebo in PR and CR subgroups with respect to patient-reported outcomes.

CONCLUSION

Patients achieved clinical benefit from maintenance treatment with niraparib regardless of response to the last platinum-based therapy.

Paraffin-embedding lithography and micro-dissected tissue micro-arrays: tools for biological and pharmacological analysis of ex vivo solid tumors

There is an urgent need and strong clinical and pharmaceutical interest in developing assays that allow for the direct testing of therapeutic agents on primary tissues. Current technologies fail to provide the required sample longevity, throughput, and integration with standard clinically proven assays to make the approach viable. Here we report a microfluidic micro-histological platform that enables ex vivo culture of a large array of prostate and ovarian cancer micro-dissected tissue (MDT) followed by direct on-chip fixation and paraffination, a process we term paraffin-embedding lithography (PEL). The result is a high density MDT-Micro Array (MDTMA) compatible with standard clinical histopathology that can be used to analyse ex vivo tumor response or resistance to therapeutic agents. The cellular morphology and tissue architecture are preserved in MDTs throughout the 15 day culture period. We also demonstrate how this methodology can be used to study molecular pathways involved in cancer by performing in-depth characterization of biological and pharmacological mechanisms such as p65 nuclear translocation via TNF stimuli, and to predict the treatment outcome in the clinic via MDT response to taxane-based therapies.

Efficacy and safety of niraparib as maintenance treatment in older patients (≥ 70 years) with recurrent ovarian cancer: Results from the ENGOT-OV16/NOVA trial

OBJECTIVE

To analyze the safety and efficacy of niraparib in patients aged ≥70 years with recurrent ovarian cancer in the ENGOT-OV16/NOVA trial.

METHODS

The trial enrolled 2 independent cohorts with histologically diagnosed recurrent ovarian, fallopian tube, or peritoneal cancer who responded to platinum rechallenge, on the basis of germline breast cancer susceptibility gene mutation (gBRCAmut) status. Patients were randomized 2:1 to receive niraparib (300 mg) or placebo once daily until disease progression. The primary endpoint was progression-free survival (PFS) by blinded independent central review. Adverse events (AEs) of special interest were based on the known safety profile of poly(ADP-ribose) polymerase inhibitors.

RESULTS

Patients aged ≥70 years in the gBRCAmut cohort receiving niraparib (n = 14) had not yet reached a median PFS compared with a median PFS of 3.7 months for the same age group in the placebo arm (hazard ratio [HR], 0.09 [95% confidence interval (CI), 0.01 to 0.73]). Non-gBRCAmut patients aged ≥70 years receiving niraparib (n = 47) had a median PFS of 11.3 months compared with 3.8 months in the placebo arm (HR, 0.35 [95% CI, 0.18 to 0.71]). Median duration of follow-up in the niraparib arm was 17.3 months in patients ≥70 years and 17.2 months in patients <70 years. Frequency, severity of AEs, and dose reductions in the niraparib arm were similar in patients aged <70 and ≥ 70 years population. The most common grade ≥ 3 AEs in patients ≥70 years were hematologic: thrombocytopenia event (34.4%), anemia event (13.1%), and neutropenia event (16.4%).

CONCLUSIONS

For patients ≥70 years of age receiving niraparib as maintenance treatment in the ENGOT-OV16/NOVA trial, PFS benefits and incidence of any grade or serious treatment-emergent AEs were comparable to results in the younger population. Use of niraparib should be considered in this population.

Evolution of genetic assessment for BRCA-associated gynaecologic malignancies: a Canadian multisociety roadmap

The landscape of genetic testing in ovarian cancer patients has changed dramatically in recent years. The therapeutic benefits of poly ADP-ribose polymerase (PARP) inhibitors in treatment of BRCA1/2-related ovarian cancers has resulted in an increased demand and urgency for genetic testing results, while technological developments have led to widespread use of multi-gene cancer panels and development of tumour testing protocols. Traditional genetic counselling models are no longer sustainable and must evolve to match the rapid evolution of genetic testing technologies and developments in personalized medicine. Recently, representatives from oncology, clinical genetics, molecular genetics, pathology, and patient advocacy came together to create a national multi-disciplinary Canadian consortium. By aligning stakeholder interests, the BRCA Testing to Treatment (BRCA TtoT) Community of Practice aims to develop a national strategy for tumour and germline BRCA1/2 testing and genetic counselling in women with ovarian cancer. This article serves to provide an overview of the recent evolution of genetic assessment for BRCA1/2-associated gynecologic malignancies and outline a Canadian roadmap to facilitate change, improve genetic testing rates, and ultimately improve outcomes for hereditary ovarian cancer patients and their families.