Adjuvant chemotherapy dosing in low-income women: the impact of Hispanic ethnicity and patient self-efficacy

Racial disparities in chemotherapy administration for early-stage breast cancer: a systematic review and meta-analysis

PURPOSE

We conducted a systematic review and meta-analysis to measure the extent to which race is associated with delayed initiation or receipt of inadequate chemotherapy among women with early-stage breast cancer.

METHODS

We performed a systematic search of all articles published from January 1987 until June 2017 within four databases: PubMed/Medline, EMBASE, CINAHL, and Cochrane CENTRAL. Eligible studies were US-based and examined the influence of race on chemotherapy delays, cessation, or dose reductions among women with stage I, II, or III breast cancer. Data were pooled using a random effects model.

RESULTS

A total of twelve studies were included in the quantitative analysis. Blacks were significantly more likely than whites to have delays to initiation of adjuvant therapy of 90 days or more (OR 1.41, 95% CI 1.06-1.87; X² = 31.05, p < 0.00001; I² = 90%). There was no significant association between race and chemotherapy dosing. Due to overlap between studies assessing the relationship between race and completion of chemotherapy, we conducted two separate analyses. Black patients were significantly more likely to discontinue chemotherapy, however, this was no longer statistically significant when larger numbers of patients with more advanced (stage III) breast cancer were included.

CONCLUSIONS

These results suggest that black breast cancer patients experience clinically relevant delays in the initiation of adjuvant chemotherapy more often than white patients, which may in part explain the increased mortality observed among black patients.

Impact of race, ethnicity, and BMI on achievement of pathologic complete response following neoadjuvant chemotherapy for breast cancer: a pooled analysis of four prospective Alliance clinical trials (A151426)

Previous studies demonstrated poor response to neoadjuvant systemic therapy (NST) for breast cancer among black women and women who are overweight or obese, but this may be due to chemotherapy underdosing. We assessed associations of race, ethnicity, and body mass index (BMI) with pathologic complete response (pCR) in clinical trial populations. 1797 women enrolled in four NST trials (CALGB 40601, 40603; ACOSOG Z1041, Z1071) were included. Tumor subtypes were defined by estrogen receptor (ER) and HER2 status. Logistic regression generated odds ratios (OR) and 95 % confidence intervals (CI) for the associations of race, ethnicity, and BMI with in-breast pCR adjusting for subtype, study arm, lymph node status, tumor size, and tumor grade. 253 (14.1 %) were black, 199 (11.1 %) Hispanic, 520 (28.9 %) overweight, and 743 (41.4 %) obese. Compared to whites, Blacks and Hispanics were more likely to be obese and Blacks were more likely to have triple-negative cancer. pCR rates differed significantly by tumor subtype. In multivariate analyses, neither race (black vs white: OR 1.18, 95 % CI 0.85-1.62) nor ethnicity (Hispanic vs non-Hispanic; OR 1.30, 95 % CI 0.67-2.53) were significant predictors of pCR overall or by subtype. Overweight and obese women had lower pCR rates in ER+/HER2+, but higher pCR rates in ER-/HER2+ cancers. There was no difference in pCR according to race or ethnicity. Overall, there was no major difference in pCR rates by BMI. These findings suggest that pCR with optimally dosed NST is a function of tumor, rather than patient, biology.