Breast cancer treatment delays by socioeconomic and health care access latent classes in Black and White women

Abstract

Background: Breast cancer mortality is higher for Black and younger women. This study evaluated 2 possible contributors to disparities-time to treatment and treatment duration-by race and age.

Methods: Among 2841 participants with stage I-III disease in the Carolina Breast Cancer Study, we identified groups of women with similar patterns of socioeconomic status (SES), access to care, and tumor characteristics using latent class analysis. We then evaluated latent classes in association with treatment delay (initiation >60 days after diagnosis) and treatment duration (in quartiles by treatment modality).

Results: Thirty-two percent of younger Black women were in the highest quartile of treatment duration (versus 22% of younger White women). Black women experienced a higher frequency of delayed treatment (adjusted relative frequency difference [RFD], 5.5% [95% CI, 3.2%-7.8%]) and prolonged treatment duration (RFD, 8.8% [95% CI, 5.7%-12.0%]). Low SES was significantly associated with treatment delay among White women (RFD, 3.5% [95% CI, 1.1%-5.9%]), but treatment delay was high at all levels of SES in Black women (eg, 11.7% in high SES Black women compared with 10.6% and 6.7% among low and high SES White women, respectively). Neither SES nor access to care classes were significantly associated with delayed initiation among Black women, but both low SES and more barriers were associated with treatment duration across both groups.

Conclusions: Factors that influence treatment timeliness persist throughout the care continuum, with prolonged treatment duration being a sensitive indicator of differences by race, SES, and care barriers.

Keywords: breast cancer; health care disparities; latent class analysis; racial disparities; treatment delay; treatment duration.

Figure 1.. Flow diagram of stage, delayed initiation, and prolonged treatment duration among 2,841 cases in the Carolina Breast Cancer Study Phase 3 (2008-2013).

All cases included first, primary breast cancers stage I to III, who received surgical treatment within 18-months of diagnosis. Treatment initiation is defined by days since diagnosis and split by timely and delayed treatment initiation, where timely indicates ≤60 days (delayed = >60 days) from diagnosis to first treatment (definitive surgery, chemotherapy [adjuvant or neoadjuvant], or radiation). Treatment duration is defined based on quartiles of patients with the same treatment modality (definitive surgery, chemotherapy, or radiation) and split by timely and prolonged treatment duration, were timely indicates quartiles 1 to 3 (prolonged = quartile 4) of time interval, in days, between the date of first treatment and the date of the last treatment (definitive surgery, chemotherapy, or radiation).

Figure 2.. Proportions of delayed initiation and prolonged treatment duration by race and age in the Carolina Breast Cancer Study Phase 3 (2008-2013).

Each percentage represents a proportion of delayed initiation and prolonged treatment duration within each race and age category. Treatment initiation is defined by days since diagnosis. Treatment duration is defined based on quartiles of patients with the same treatment modality.