Study: Gaps in genetic testing and decision-making for women with early-stage breast cancer

IN-DEPTH REVIEW OF RESEARCH

Study background:

Genetic testing is becoming more common for breast cancer patients, helping patients and providers make decisions about treatment and surgery. National guidelines recommend that patients see experts known as genetic counselors before and after genetic testing. However, experts are concerned that there are not enough genetics experts to meet the growing need.

Allison Kurian, MD and colleagues from Stanford University School of Medicine and other institutions published work in the Journal of Clinical Oncology that examines how genetic testing results affect treatment decisions for patients with early-stage breast cancer. They also surveyed surgeons on their recommendations for mastectomy versus lumpectomy based on their patients’ genetic test results.

As the research study authors write, “The genetic counselor workforce is insufficient to meet the growing demand for timely incorporation of genetic testing into treatment decisions.” Because of this, healthcare providers such as surgeons, medical oncologists and other physicians may feel that they need to counsel patients about their genetic testing results, which may be difficult for some healthcare providers who have limited experience with genetic testing.

Researchers of this study wanted to know:

How genetic testing results affect surgical and treatment recommendations and decisions for women who have been diagnosed with early-stage breast cancer.

Population(s) looked at in the study:

The 666 women involved in this study were identified by Surveillance, Epidemiology, and End Results (SEER) registries from Georgia and Los Angeles County. These women were between 20 and 79 years old, were diagnosed between 2014 and 2015 with stage 0-II breast cancer, and reported that they already had genetic testing. The study included 57% non-Hispanic whites, 18% blacks, 14% Hispanics and 9% Asians.

Providers who ordered genetic testing for the patients in this study included surgeons, medical oncologists, and genetic counselors. Patients reported talking about their genetic test results with surgeons only, medical oncologists only, genetic counselors only, or multiple health professionals.

Two months after their breast cancer surgeries, patients answered a questionnaire that included questions regarding genetic testing, whether they discussed their genetic testing results with a health care professional or genetic counseling expert, when they received their results, the genetic testing result, who ordered the genetic test, surgical procedures, and race.

Surgeons were also surveyed. They responded about the number of new patients with breast cancer they treated in the past year and their confidence in discussing the pros and cons of genetic testing with their patients. Regarding patients who were candidates for genetic testing, surgeons were asked how often they referred women for genetic counseling ordered testing without a referral for genetic counseling, and delayed surgery until test results were obtained. Surgeons were also asked whether they would offer breast-conserving treatment as a reasonable option for someone with a BRCA1 or 2 mutation or if they would manage a patient with a VUS in the same way they would manage a BRCA mutation carrier.

Study findings:

Of the 666 women who participated in this study, 53 had a mutation in BRCA1, BRCA2, or other gene known to increase cancer risk; 59 had a variant of uncertain significance (VUS); and 463 had no mutation (pathogenic or VUS) in any of the genes tested. The remainder of the 666 women did not report their genetic testing result.

• Approximately half of the 666 women who reported genetic testing talked with a genetic counselor about their results.
• 80% of the women who had a mutation in a gene known to increase cancer risk decided to a have bilateral mastectomy.
• 51% of the women who had a VUS in a gene known to increase cancer risk decided to have a bilateral mastectomy.
• 16% of patients with no mutation and no VUS decided to have a bilateral mastectomy.

337(the overall response rate was 78%) surgeons were surveyed. Of these, 98 (29%) indicated that they saw a high volume of breast cancer patients (51 or more treated in the past year). 128 (38%) indicated that they saw a low volume of breast cancer patients (0 to 20 treated in the past year). 101 (30%) indicated that they saw a moderate number of patients while 10 (3%) did not report on number of breast cancer patients seen.

• About one-fourth of surgeons who saw a high volume of new breast cancer patients managed women with a VUS as though they had a deleterious mutation.
• About half of surgeons who saw a low volume of new breast cancer patients managed women with VUS as though they had a deleterious mutation.

Limitations:

The patient survey data used in this study may include inaccuracies due to errors in recall. Patient medical records were not reviewed to validate how well they remembered details about their situation or care. The study did not look at other reasons why patients may have chosen double mastectomy or the degree that they were involved in the decision-making process. Additionally, while the study began with 666 women, only a relatively small sample size, 53 carried a deleterious mutation, and only 59 had a VUS. Because the study was conducted in Los Angeles and Georgia, the results may not apply to other areas in the United States.

Conclusions:

Previous research indicated that bilateral mastectomy does not increase survival for average-risk women. For this reason, most surgeons recommend lumpectomy for treatment of breast cancer in women who do not carry a gene mutation and are not considered at high risk for further cancer. However, bilateral mastectomy does reduce the risk of a second breast cancer diagnosis. This is particularly relevant for women who carry a mutation in BRCA1/2 or another gene that increases breast cancer risk. The study authors write that, “It is essential that patients understand the meaning of their results and that [bilateral mastectomy] be discussed with mutation carriers but not recommended for women with negative or VUS results.” This study suggests that a substantial number of women with early-stage breast cancer who have genetic testing and carry a VUS are having bilateral mastectomy.

Additionally, some surgeons are treating their breast cancer patients who carry a VUS as though they carry a deleterious mutation that is known to increase cancer risk. While each patient should have a personalized care and treatment plan that is best for them, patients should make sure that they discuss their genetic testing results with a genetics professional. The results of this research highlight the challenge of including rapidly advancing genetic testing technology into personalized breast cancer treatment.

Posted 7/14/17