Life-saving cancer genetic testing vastly underutilized

December 04, 2015

Approximately 10 percent of all cancers have a strong hereditary component. The Society of Gynecologic Oncologists (SGO) estimates that more than 500,000 American women are at a high-risk of developing hereditary cancers, which include breast, ovarian, colon and uterine cancers. Two of the most common familial syndromes that cause gynecologic cancers are familial breast-ovarian cancer syndrome, and hereditary non-polyposis colorectal cancer syndrome (HNPCC), which confers a high risk for uterine and ovarian cancers, in addition to colon cancer.

The study, "Cancer Risk Assessment in a Community Setting: Prevalence of Patients with High Risk Family Histories," was led by Michael Manuel, M.D., M.P.H., a gynecologic oncologist in private practice in San Jose, Calif. Dr. Manuel conducted the study at the large community-based mammography center, Breast Care Center at Good Samaritan Hospital, also in San Jose.

"This study is important because these are real people in an average American community. The troubling aspect is that the high risk women we identified [through patient surveys] were unaware of their elevated risk for developing hereditary cancers," said Dr. Manuel. "We need community education and resources to allow identification of women with strong family histories of cancer. Referral to genetic counselors for accurate risk assessment and genetic testing when appropriate can prevent cancer deaths. Women who carry mutations in cancer causing genes should undergo more intensive cancer screening and, in many cases, preventative surgery is advised."

"Although genetic testing for gynecologic and other hereditary cancers has been available for over a decade, awareness of this potentially life-saving intervention is woefully inadequate among both physicians and the public," said Andrew Berchuck, M.D., incoming president of SGO. "Women are needlessly dying of cancers that could have been prevented entirely or detected at an early stage while their disease was still curable. We have all of this great knowledge to help reduce cancer mortality in high-risk women, but most women are unaware of their personal risk and the available help."

A clear understanding of a family's history of cancer is vital to reducing deaths associated with hereditary cancers. There are many options available to women who are at risk of developing hereditary cancers including genetic counseling and testing, preventative surgery and screening programs. Women should discuss past and present personal and family history of cancer with their primary physicians and gynecologists on an annual basis. These doctors can help determine the potential risks, as well as the best modality of treatment or screening that could very well save a woman's life.

Women should also take advantage of available resources such as the Women's Cancer Network's online cancer risk assessment. Developed by physicians who are gynecologic cancer experts, the assessment is free and confidential, providing a wealth of information on a woman's potential risk for cancer.

This study assessed the prevalence of patients with a high-risk family history of cancer in a community setting. The cancer syndromes assessed included breast/ovarian, hereditary non-polyposis colorectal cancer (HNPCC) or Lynch syndrome, and p16/melanoma.

Approximately 10% of breast, ovarian, colon and uterine cancers are linked to known genetic mutations that confer a high risk of cancer throughout a family. Specifically, Breast Cancer (BRCA) 1 and 2 mutations increase a person's lifetime risk of breast cancer to greater than 80% and ovarian cancer to 20 - 65%. Similarly, persons inheriting a mutation in one of the HNPCC genes (MLH1, MSH2, or MSH6) have a lifetime risk of colon cancer approaching 90% and uterine cancer risk of 40-70%. These individuals also have a 12% lifetime risk of ovarian cancer, as well as increased risks of stomach cancer. More recently, mutations in the p16 gene have been associated with increased risks of melanoma and pancreas cancer.

Surveys were handed out over a four-month period to all patients presenting for mammography services at a large, community-based mammography center. Interest in completing a family-history survey was high, resulting in 2,745 surveys collected. The surveys were divided into high or low risk categories.

Of the 2,745 surveys collected, there were a total of 313 (11.4%) patient family histories that indicated a substantial probability for a genetic mutation in BRCA, HNPCC, or p16/melanoma. Of the high-risk surveys, most were indicative of a possible BRCA mutation (88.4%), versus HNPCC (6.0%), p16/melanoma (3.8%), or more than one syndrome (1.5%). The total number of patients with a previous personal history of cancer who also met high-risk hereditary cancer criteria was 148 or 47.2% of the high-risk surveys.

Although 69.9% of patients indicated interest in follow-up to obtain more information, less than 3% of those found to be high risk had undergone genetic counseling/testing at the time of data collection/analysis.

While interest in completing this study was high, few patients were aware of these syndromes and the high risk of developing cancer if a genetic mutation is found. Fewer still sought genetic counseling or indicated an intention to seek genetic consultation. This study demonstrates a clear need for community education and outreach, as well as facilitated access to genetic counseling and/or testing services for high risk women and their families.

"Cancer Risk Assessment in a Community Setting: Prevalence of Patients with High Risk Family Histories," was conducted by Dr. Manuel, Shannon Kieran, M.S., and James Lilja, M.D., from Bay Area Gynecologic Oncology practice, San Jose, Calif. The study would not have been possible without the support of the Breast Care Center at Good Samaritan Hospital, San Jose, Ca.; Mary Beattie, M.D. and Beth Crawford, University of California, San Francisco Cancer Risk Program; California Center for Healthcare and Biotechnology Foundation; and Myriad Genetics Laboratories.

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