Disparities in Uptake of BRCA1/2 Genetic Testing in a Randomized Trial of Telephone Counseling

摘要

Genetic counseling via telephone (TC) has emerged as a potential avenue of care for women at risk of breast and ovarian cancers and open to BRCA1 and BRCA2 genetic testing. However, although TC has been shown to be on level with usual care (UC) methods in terms of knowledge, satisfaction, decisional quality, quality of life, and distress, all while yielding high cost savings to the patient and increasing patient accessibility, studies have also shown that patients randomized to TC are less like to complete the genetic testing process. In order to determine the factors leading to lower rates of genetic testing uptake after TC, the authors of this study examined sociodemographic, medical, and psychosocial predictors of genetic testing uptake and evaluated patient-related moderators (knowledge, numeracy, race/ethnicity, education level, etc) in a large cohort of women. In this noninferiority trial, 669 women (21-85 years old) seeking BRCA1/2 genetic testing, with no history of counseling or testing, were randomized into 2 groups, a TC group (n = 335) and an in-person counseling or UC group (n = 334). Measures included sociodemographics, medical history, intentions for risk-reducing surgery, perceived risk of BRCA mutation, perceived risk of breast and ovarian cancer, knowledge, numeracy, decisional conflict, cancer-specific distress, and quality of life. Analysis, logistic regression with backward elimination, was conducted within an intention-to-treat (ITT) sample, which included all randomized participants regardless of genetic counseling session completion, and with a per-protocol (PP) sample, limited to participants who completed genetic counseling as assigned. Within both the ITT and PP samples, genetic testing uptake was lower in the TC group than in the UC group (ITT: 74.9% vs 81.4%, P = 0.04; PP: 84.2% vs 90.1%, P = 0.03). In the ITT population, independently associated significant predictors of completing genetic testing were non-Hispanic white race/ethnicity (odds ratio [OR], 1.96; P = 0.007), randomization to UC (OR, 1.48; P = 0.045), higher knowledge (OR, 1.12; P = 0.018), and lower perceived stress (OR, 0.89; P = 0.017). In the PP sample, independently associated predictors were marital status (OR, 1.85; P = 0.017), objective mutation risk (OR, 1.22; P = 0.007), knowledge (OR, 1.13; P = 0.050), and randomization to UC (OR, 1.65; P =0.050). Considering both ITT and PP analyses, it is of note that knowledge, perceived stress, and objective risk did not interact with group assignment in either analysis (marital status was not tested). In regard to potential moderator variables, the only variable that reached statistical and clinical significance in both samples was race/ethnicity (ITT: P =0.054; PP: P = 0.028). Overall, the strongest moderator affecting genetic testing uptake after TC was race/ethnicity. When randomized to TC, minority women were less likely to complete BRCA1/2 genetic testing. Despite these lower rates, which may be due in part to practical barriers (unlike UC patients, TC patients need to travel to an alternate location to provide a DNA sample), this finding needs to be balanced with the possibility that TC may increase access in the first place. Further studies on availability of TC and its effect on overall rates should be conducted as other modes of delivery emerge for genetic counseling and testing.