Narrowing Racial Gaps in Breast Cancer: Factors Affecting Probability of Adjuvant Radiation Therapy

Purpose: Adjuvant radiation therapy has historically been underused by black patients with breast cancer compared with white patients. We prospectively investigated factors, including sociocultural, psychosocial, and health care factors, that may be associated with the use or omission of adjuvant radiation therapy by both racial groups. Methods and Materials: Women with primary invasive, nonmetastatic breast cancer were recruited from hospitals and through community outreach efforts in the Washington, DC, and Detroit, Michigan, areas between July 2006 and April 2011. Data were collected via telephone interviews regarding psychosocial (eg, self-efficacy) and health care factors (eg, communication) at the time they received a diagnosis. Clinical data were extracted from their medical charts after the completion of treatment. We examined the association among multiple demographic, socio-cultural, healthcare process factors and the use of radiotherapy. Logistic multivariable regression models identified associations with radiotherapy receipt. Results: Among 395 eligible and consenting women, 315 had complete baseline data, and 217 were in the final analytical sample, having met criteria for adjuvant breast or chest wall radiation therapy after breast conservation surgery or mastectomy. Among women eligible for radiation, all were insured, 59% were black, the mean age was 55.4 years, and the majority had stage I or II disease. Overall, approximately 70% percent of women received adjuvant radiation therapy. On multivariable analyses, the likelihood of receiving adjuvant radiation therapy was higher for those who were black with any level of indication for radiation therapy (odds ratio 2.21; P < .01), those for whom comorbidities were present, and those who demonstrated positive sociocultural factors such as self-efficacy and high reported rates of provider communication about radiation therapy (odds ratio 1.20; P < .05). Among women with strong indications for radiation therapy, there was no significant association with race on multivariable analysis. Conclusions: Our findings suggest that among women with any indication for radiation therapy, black patients were more likely to receive radiation therapy compared with white patients. Furthermore, data suggest improved provider communication and self-efficacy are important predictors of receipt of radiation therapy. Further studies exploring the effects of provider communication and sociocultural factors to diverse patient populations may be warranted.