Biospecimen donation among black and white breast cancer survivors: opportunities to promote precision medicine.

PURPOSE: Advances in precision medicine (PM) have potential to reduce and/or eliminate breast cancer disparities in both treatment and survivorship. However, compared to white Americans, black Americans are often underrepresented in genetic research. This report assessed factors that influence receipt of buccal cells via saliva kits.

METHODS: This prospective study recruited women with confirmed hormonal-positive (HR+) breast cancer (BC). A standardized telephone survey collected sociodemographic, socio-cultural (e.g., religiosity), and healthcare process factors. Clinical information was abstracted from medical records. After the baseline survey, return postage-paid envelopes and mouthwash collection kits were mailed. Univariate and adjusted logistic regression models estimated the probability of biospecimen donation.

RESULTS: Seventy percent of the sample provided buccal cells which were of good quality. No differences were noted by race or other demographic factors. In the multivariable logistic model, time spent with providers (OR 1.61 per 1-point increase; 95% CI 1.242, 2.088) and religiosity (OR 0.957 per 1-point increase; 95% CI 0.931, 0.984) remained associated with biospecimen provision. Women with lower-stage cancer (vs. higher stage III+) were more likely to donate biospecimens (p < 0.05).

CONCLUSIONS: Cancer care experiences predicted specimen donation. Understanding the contextual reasons for lower receipt among women with higher religiosity scores and higher stage warrants further examination.

IMPLICATIONS FOR CANCER SURVIVORS: PM is relevant to cancer survivors because of its potential to inform targeted therapies, understand disease resistance, and aide in prediction of toxicity and/or recurrence. Future efforts to launch precision medicine trials with BC survivors may benefit from engaging medical oncologists and/or leveraging patient-provider encounters for trial participation.