July 2024 | George M. Pikler, M.D., Ph.D., FACP, Lead Oncology Advocate N1X10

Family Matters: Testing for Inherited Gene Mutations

Cancer is a genomic disease in that gene alterations drive the cellular growth and immune surveillance perturbations that enable malignant cells to take hold and to metastasize. The incorporation of next-generation sequencing (NGS) in routine clinical practice has led to the identification of cancer-predisposing mutations in an increasing proportion of patients with several types of cancers. Such tests, often called biomarker tests can help oncologists choose which treatments may be most effective for those patients.

Guidelines from several medical organizations recommend that individuals diagnosed with a host of different cancers also undergo germline testing to identify an inherited etiology. Like biomarker tests, germline testing can help oncologists determine the best targeted cancer therapies for patients, but such testing may also help identify people whose family members should be offered testing for potential cancer-related genes inherited from a parent.

Appropriate germline genetic testing depends on an accurate family history of cancer. While testing for some patients is indicated regardless of family history, for others, family history can determine testing eligibility. In addition, family history informs which genes should be included in a genetic panel beyond those indicated by a patient’s personal history. Family history is also crucial for the proper interpretation of genetic test results (both positive and negative) to guide personalized screening and prevention recommendations for patients and their family members. These tests may have major implications, not only for the patient but also for the whole family, and these will add to the medical, social, and psychological burden of disease.

Currently, National Comprehensive Cancer Network (NCCN) recommendations include universal multigene germline testing for patients with pancreatic, breast and ovarian cancer, as well as for those with metastatic prostate cancer and those younger than 50 years with colorectal cancer. For other cancers, different professional societies (and various payers) have divergent guidelines, including the genes to be tested. With advances in sequencing technology, the number of genes tested has increased and costs have declined. An informed consent that explains all the caveats of tumor sequencing and its consequences, including the possibility of a need for germline testing, should be clearly communicated to patients and their families.

ASCO Educational Book. 2023; June 30
JAMA. 2023; June 5

Erica Cross, PA

PA

Erica is a board certified Physician Assistant. She obtained her Master’s degree in Physician Assistant studies from Our Lady of the Lake College in Baton Rouge, LA. She began practicing in 2011 and has worked clinically in Orthopedics and Dermatology. The majority of her career has been spent in a Dermatology practice where she assisted in Mohs surgery, treating various types of skin cancer. She also teaches in the medical simulation department at the University of South Alabama and enjoys every aspect of medical education.