Disparities in Guideline-Concordant Initial Systemic Treatment in Women with HER2-Negative Metastatic Breast Cancer: A SEER-Medicare Analysis

Abstract

Background Data on guideline-concordant initial systemic treatment among women with HER2-negative metastatic breast cancer (MBC) are limited. We determined the proportion of women with HER2-negative MBC who received guideline-concordant treatment and the extent to which independent variables explained differences in guideline-concordant treatment by hormone receptor (HR) status. Methods We conducted a retrospective cohort study using the SEER-Medicare database. We included women age >65 years diagnosed with HER2-negative MBC during 2010–2013. We used the National Comprehensive Cancer Network treatment guidelines to determine guideline-concordant initial treatment within the first 6 months of a cancer diagnosis. We conducted a multivariable logistic regression to identify the significant predictors of guideline-concordant treatment and a non-linear decomposition method to examine disparities by HR status. Results Among 1089 eligible women, 72.3% received guideline-concordant treatment. Compared to women who did not receive guideline-concordant treatment, women who received guideline-concordant treatment were more like to be comparatively older (p<0.05), married (p=0.0171), resided in areas with higher proportion of people age ≥25 years with at least four years of college education, and had positive HR status (p<0.0001). Approximately 8% of the disparity in guideline-concordant treatment by HR status was explained by their observed characteristics. Need-related factors explained the highest proportion (66.9%) of the disparity. Conclusion Our findings indicate improvement of care for older women, who are single/divorced, have negative HR status, and who live in area with lower education levels. Unexplained disparities in guideline-concordant treatment by HR status can be attributed to patient preferences for treatment, physician-level factors, and perceptions.

The impact of geographical and sociodemographic variation on access to Systemic Anti- Cancer Therapies for Secondary Breast Cancer: A systematic review

“…The rst reported a higher proportion of chemotherapy use in those women with hormone receptor negative disease p < .001 (23). The second reported a decreased likelihood of receipt of systemic ant cancer therapies for women with hormone receptor negative disease OR 0.25 (0.17-0.36) (22).…”

“…Women with fewer comorbidities were more likely to receive treatment (23,32). A greater proportion of chemotherapy use was reported for women with hormone receptor negative disease and women with triple negative disease were less likely to receive guideline concordant treatment (22,23).…”

“…Overall receipt of immunotherapy reported in one study was 4% (29). Four remaining studies reported treatment receipt with SACT which was unspeci ed, described as treatment, 'no rst course therapy' and care NCI CCC care which included systemic therapies (20,13,22,33). In the study which reported women who did not receive a rst course of treatment this ranged from 11.1% − 25.5% with 12.8% of women with a breast cancer diagnosis who did not receive a rst course of treatment (31).…”

“…Hormone receptor status was reported across four moderate quality studies which reported data exclusively for patients with a secondary breast cancer diagnosis (19,21,22,23). Two studies reported chemotherapy receipt and receipt of systemic anti-cancer therapies respectively (22,23). The rst reported a higher proportion of chemotherapy use in those women with hormone receptor negative disease p < .001 (23).…”

“…Included studies varied in the numbers of women with SBC for whom data could be extracted. Five (n = 5) studies included women with secondary breast cancer exclusively (19,20,21,22,23) The remaining studies (n = 10) included subgroups and cohorts of women with a secondary diagnosis. These ranged from three to twenty one percent of the overall sample.…”