Genetics of Breast and Ovarian Cancer (PDQ®): Genetics - Health Professional Information [NCI] - Psychosocial Issues in Inherited Breast Cancer Syndromes
Furthermore, accrual statistics in different populations are difficult to compare because there are many points in the genetic risk assessment process at which a family member can decline, and no standard method of reporting these rates has been developed. Factors that may influence uptake of testing include the following:
- Cost of genetic testing.
- How informative testing would be (e.g., presence of a known mutation in the family or ethnic group vs. lack of an identified mutation).
- Extent to which genetic test results are likely to influence clinical decision-making.
Motivations for testing include the belief that testing positive would increase one's motivation to get regular clinical breast examinations, to do breast self-exams, and to get recommended mammograms. Women known to be at increased risk do not necessarily adhere to screening recommendations at higher rates than women at population risk, nor do they necessarily pursue or complete genetic testing, though the data on this subject are contradictory.[19,20,21] An additional motivation for testing is to receive information that would benefit other family members.
Another motivator for testing may be recommendation by a physician. In a retrospective study of 335 women considering genetic testing, 77% reported that they wanted the opinion of the genetics physician about whether they should be tested, and 49% wanted the opinion of their primary care provider. However, there is some evidence of referral bias favoring those with a maternal family history. In a Canadian retrospective review of 315 patients, those with a maternal family history of breast cancer or ovarian cancer were 4.9 times (95% CI, 3.6–6.7) more likely to be referred for a cancer genetics consultation by their physician than were those with a paternal family history (P < .001). Studies have found that physicians may not adequately assess paternal family history  or may underestimate the significance of a paternal family history for genetic risk.[25,26,27]
In one study of women who pursued BRCA1 and BRCA2 mutation testing and received uninformative test results, 45% (17/40) were interested in undergoing additional testing for five large rearrangements (deletions and insertions) in the BRCA1 gene. There were no significant differences in BRCAPRO scores, age at time of genetic testing, number of children, or number of siblings between individuals who chose to pursue additional testing and those who declined. Women who chose to undergo additional testing were significantly less likely to have a diagnosis of breast or ovarian cancer at the time of initial testing.
Limited data are available about the characteristics of at-risk individuals who decline to be or have never been tested. It is difficult to access samples of test decliners since they are people who also may be reluctant to participate in research studies. Studies of testing are difficult to compare because people may decline at different points and with different amounts of pretest education and counseling. One study found that 43% of affected and unaffected individuals from hereditary breast/ovarian cancer families completing a baseline interview regarding testing declined. Most individuals declining testing chose not to participate in educational sessions. Decliners were more likely to be male and unmarried and had fewer relatives affected with breast cancer. Those decliners who had high levels of cancer-related stress had higher levels of depression. Decliners lost to follow-up were significantly more likely to be affected with cancer. Another study looked at a small number (n = 13) of women decliners who carry a 25% to 50% probability of harboring a BRCA mutation and found that these nontested women were more likely to be childless and have a higher educational level. This study showed that most women had decided not to undergo the test after serious deliberation about the risks and benefits. Satisfaction with frequent surveillance was given as one reason for nontesting in most of these women. Other reasons for declining included having no children and becoming acquainted with breast/ovarian cancer in the family relatively early in their lives.[29,30] A third study evaluated characteristics of 34 individuals who declined BRCA1/BRCA2 testing in a large multicenter study in the United Kingdom. Decliners were younger compared with a national sample of test acceptors, and female decliners had lower mean scores on a measure of cancer worry. Although 78% of test decliners/deferrers felt that their health was at risk, they reported that learning about their BRCA1/BRCA2 mutation status would cause them to worry about the following:
- Their children's health (76%).
- Their life insurance (60%).
- Their own health (56%).
- Loss of their job (5%).
- Receiving less screening if they did not carry a BRCA1/BRCA2 mutation (62%).