Outcomes after targeted treatment based on somatic tumor genetic testing for women with gynecologic cancers

Phase II Trial of Cisplatin, Gemcitabine, and Intensity-Modulated Radiation Therapy for Locally Advanced Vulvar Squamous Cell Carcinoma: NRG Oncology/GOG Study 279

PURPOSE

To assess efficacy and toxicity of cisplatin (C) and gemcitabine (G) with intensity-modulated radiation therapy (IMRT) in patients with locally advanced vulvar cancer not amenable to surgery.

METHODS

Patients enrolled in a single-arm phase II study. Pretreatment inguinal-femoral nodal assessment was performed. Sixty-four Gy IMRT was prescribed to the vulva, with 50-64 Gy delivered to the groins/low pelvis. Radiation therapy (RT) plans were quality-reviewed pretreatment. C 40 mg/m2 and G 50 mg/m2 were administered once per week throughout IMRT. Complete pathologic response (CPR) was the primary end point. Progression-free survival (PFS) and overall survival (OS) were estimated using the Kaplan-Meier method, and adverse events were assessed with Common Terminology Criteria for Adverse Events v 4.0.

RESULTS

Fifty-seven patients enrolled, of which 52 were evaluable. The median age was 58 years (range, 25-58), and 94% were White. Forty (77%) had stage II or III disease, and all had squamous histology. A median of six chemotherapy cycles (range, 1-8) were received. Eighty-five percent of RT plans were quality-reviewed with 100% compliance to protocol. Seven patients came off trial because of toxicity or patient withdrawal. Of 52 patients available for pathologic assessment, 38 (73% [90% CI, 61 to 83]) achieved CPR. No pelvic exenterations were performed. With a median follow-up of 51 months, the 12-month PFS was 74% (90% CI, 62.2 to 82.7) and the 24-month OS was 70% (90% CI, 57 to 79). The most common grade 3 or 4 adverse events were hematologic toxicity and radiation dermatitis. There was one grade 5 event unlikely related to treatment.

CONCLUSION

Weekly C and G concurrent with IMRT sufficiently improved CPR in women with locally advanced vulvar squamous cell carcinoma not amenable to surgical resection.

Evaluation of Homologous Recombination Deficiency in Ovarian Cancer

OPINION STATEMENT

Homologous recombination deficiency (HRD) is an important biomarker guiding selection of ovarian cancer patients who will derive the most benefit from poly(ADP-ribose) polymerase inhibitors (PARPi). HRD prevents cells from repairing double-stranded DNA damage with high fidelity, PARPis limit single-stranded repair, and together these deficits induce synthetic lethality. Germline or somatic BRCA mutations represent the narrowest definition of HRD, but do not reflect all patients who will have a durable PARPi response. HRD can also be defined by its downstream consequences, which are measured by different metrics depending on the test used. Ideally, all patients will undergo genetic counseling and germline testing shortly after diagnosis and have somatic testing sent once an adequate tumor sample is available. Should barriers to one test be higher, pursuing germline testing with reflex to somatic testing for BRCA wildtype patients or somatic testing first strategies are both evidence-based. Ultimately both tests offer complementary information, germline testing should be pursued for any patient with a history of ovarian cancer, and somatic testing is valuable at recurrence if not performed in the upfront setting. There is a paucity of data to suggest superiority of one germline or somatic assay; therefore, selection should optimize turnaround time, cost to patients, preferred result format, and logistical burden. Each clinic should implement a standard testing strategy for all ovarian cancer patients that ensures HRD status is known at the time of upfront chemotherapy completion to facilitate comprehensive counseling about anticipated maintenance PARPi benefit.

Molecular portraits of clear cell ovarian and endometrial carcinoma with comparison to clear cell renal cell carcinoma

OBJECTIVE

Advanced clear cell gynecologic malignancies remain among the most challenging diseases to manage. We evaluated ovarian and endometrial clear cell carcinoma (OCCC and ECCC) specimens using comprehensive sequencing technology to identify mutational targets and compared their molecular profiles to histologically similar clear cell renal cell carcinoma (ccRCC).

METHODS

Using next-generation sequencing (NGS), fragment analysis (FA), and in situ hybridization (ISH), 164 OCCC, 75 ECCC and 234 ccRCC specimens from 2015 to 2018 were evaluated and compared.

RESULTS

The highest mutation rates in ECCC and OCCC were noted in: ARID1A (75.0%, 87.5%), TP53 (34.8%, 11.1%), PIK3CA (25.0%, 46.8%), PPP2R1A (8.7%, 16.7%), MSI-high (8.8%, 6.4%) and PTEN (8.3%, 7.1%). Among these mutations, there was no significant difference between OCCC and ECCC mutation prevalence except in TP53, with higher mutation rates in ECCC versus OCCC (34.8 vs. 11.1%, respectively, p < 0.05). ccRCC demonstrated different mutation profiles with higher mutation rates in VHL (80.3%), PBRM1 (43.9%), SETD2 (31.1%), and KDM5C (29.2%). By contrast, VHL, PBRM1, and SETD2 mutations were not found in ECCC and OCCC (0.0%). Compared to ccRCC and ECCC, OCCC was found to have a significantly higher tumor mutation burden (TMB) (19.1%).

CONCLUSION

Gynecologic and renal CCC demonstrate separate and disparate somatic profiles. However, OCCC and ECCC are diseases with similar profiles. TMB and MSI analyses indicate that a subset of OCCC may benefit from immunotherapy. Prospective clinical trials are needed and are underway to examine targeted therapies in these gynecologic disease subtypes.