The Importance of Genetic Testing in Ovarian Cancer: Diagnosis and Treatment

Angeles Alvarez Secord, MD, MHSc

For years, there was little progress in the development of new treatments for women with BRCA-mutated ovarian cancer. As a result, genetic testing at diagnosis was not routinely performed except for patients with a family history of cancer or a young age of onset.¹ In the last few years, however, targeted treatments have emerged, expanding treatment options, genetic testing, and tumor testing to a wider group of patients.²

These individualized treatments reinforce the importance of knowing the BRCA status of all women with ovarian cancer.³ Testing to determine whether a patient has germline and/or somatic BRCA mutations is now crucial to physicians in making informed treatment decisions.^4,5

In an interview with OncLive, Angeles Alvarez Secord, MD, MHSc, of Duke Cancer Institute, discusses the importance of genetic and tumor testing in ovarian cancer and the potential impact on treatment decisions.*

OncLive: Why is tumor testing important in ovarian cancer?

Secord: Tumor testing is used to determine if a patient has somatic mutations. It is crucial because, like germline testing, tumor testing can impact treatment decisions.^4,5 Both germline and somatic mutations have shown response to treatments that specifically target BRCA-mutated cancer cells such as PARP inhibitors.⁵

What is the difference between germline and somatic mutations?

Germline mutations are inherited and are present in all our cells at birth, while somatic mutations are acquired after birth and are present only in the cancerous tumor. Germline mutations can be passed onto your offspring, while somatic mutations cannot.⁶ While germline mutations can be identified in tissue, they require confirmation with a blood or saliva test.⁴ Somatic mutations are detected by testing a tissue sample of the tumor itself (called tumor testing or genomic testing).⁷ It is possible for a woman to have a somatic mutation in her tumor even if she does not have an inherited (germline) mutation. In turn, if a woman has a germline BRCA mutation, that mutation will also be present in her tumor cells.⁶

Who should be tested for germline and somatic genetic mutations and when?

Current guidelines, endorsed by numerous organizations including the National Comprehensive Cancer Network, American Society of Clinical Oncology, Society of Gynecologic Oncology, National Society of Genetic Counselors, and the American Congress of Obstetrics and Gynecology, now recommend genetic testing for all women with ovarian, fallopian tube and primary peritoneal cancer regardless of age or family history.^8-10 It’s important to test at diagnosis so we can identify patients with germline and/or somatic mutations to determine the most appropriate course of treatment.^4,5,11

How have ovarian cancer treatment advances impacted genetic testing?

The results of clinical trials have demonstrated that women with ovarian cancers associated with BRCA mutations benefit by adding treatments with PARP inhibitors and have significantly changed the way we approach genetic testing.¹² Genetic testing was and still is important to identify if a person or their family member(s) (cascade testing) have a genetic predisposition to cancers so that screening and preventive measures could be used.⁷ But now, with the emergence of targeted treatments such as PARP inhibitors, which target cancers that rely on the PARP enzyme to repair damaged DNA,¹³ it becomes essential to determine a patient's BRCA status at the very beginning of their diagnosis for treatment purposes.^5,11 BRCA status helps us determine which patients should receive PARP inhibitor maintenance therapy after front-line chemotherapy and assist in treatment planning for those with recurrent disease.^4,5 BRCA status provides important prognostic, preventive, and therapeutic information.⁷

What advances have there been in genetic testing?

We’ve seen genetic testing improve since 2014. Newer tests can find mutations that may have been previously missed by older tests. Thus, ovarian cancer survivors who had a negative or indeterminate genetic test before 2014 should speak with a genetic counselor or their doctor to see if additional testing is right for them.¹

*Dr. Alvarez Secord was not compensated for her participation in this article.©2019 AstraZeneca. All rights reserved. US-22328 Last Updated 6/19

References

1. Ruddy KJ, Risendal BC, Garber JE, Partridge AH. Cancer Survivorship Care: An Opportunity to Revisit Cancer Genetics. J Clin Oncol. 2016;34(6):539—541. Available online. Accessed Jan. 18, 2019.
2. Evans T, Matulonis U. PARP Inhibitors in Ovarian Cancer: evidence, experience and clinical potential. Ther Adv Med Oncol. 2017; 9(4): 253—267. Available online. Accessed Jan. 18, 2019.
3. Hennessey BT, Timms KM, Carey MS, et al. Somatic Mutations in BRCA1 and BRCA2 Could Expand the Number of Patients That Benefit from Poly (ADP Ribose) Polymerase Inhibitors in Ovarian Cancer. J Clin Oncol. 2010;28(22):3570—3576. Available online. Accessed Jan. 22, 2019.
4. National Cancer Institute. BRCA Mutations: Cancer Risk and Genetic Testing. Available online. Accessed March 7, 2019.
5. Koczkowska M, Zuk M, Gorczynski A, et al. Detection of somatic BRCA1/2 mutations in ovarian cancer — next-generation sequencing analysis of 100 cases. Cancer Med. 2016;5(7):1640-1646. Available online. Accessed March 14, 2019.
6. American Cancer Society. Changes in Genes. Available online. Accessed Jan. 22, 2019.
7. Frey MK, Pothuri B. Homologous recombination deficiency (HRD) testing in ovarian cancer clinical practice: a review of the literature. Gynecol Oncol Res Pract. 2017;4:4. Available online. Accessed March 7, 2019.
8. National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology. 2019. Available online. Accessed March 8, 2019.
9. Society of Gynecologic Oncology. SGO Clinical Practice Statement: Genetic Testing for Ovarian Cancer. 2014. Available online. Accessed March 8, 2019.
10. Lu KH, Wood ME, Daniels M, et al. American Society of Clinical Oncology Expert Statement: Collection and Use of a Cancer Family History for Oncology Providers. J Clin Oncol. 2014;10;32(8):833-840. Available online. Accessed March 14, 2019.
11. Vergote I, Banerjee S, Gerdes AM, et al. Current perspectives on recommendations for BRCA genetic testing in ovarian cancer patients. Eur J Cancer. 2016;69:127-134. Available online. Accessed March 7, 2019.
12. Neff RT, Senter L, Salani R. BRCA Mutation in Ovarian Cancer: Testing, Implications and Treatment Considerations. Ther Adv Med Oncol. 2017;9:519-531. Available online. Accessed Jan. 22, 2019.
13. National Cancer Institute. NCI Dictionary of Cancer Terms/PARP Inhibitor. Available online. Accessed Jan. 22, 2019.

Women who have not been diagnosed with ovarian cancer but are concerned about their risk for developing the disease should, most importantly, know their family history. They should also speak to their doctor or genetic counselor about whether genetic testing for inherited BRCA mutations is right for them.