Abstract PO5-16-09: Associations of age, body mass index, diabetes and hypertension with relative dose intensity among women receiving anthracycline- and/or taxane-based chemotherapy for invasive breast cancer

Abstract Research suggests that medical comorbidity is associated with reduced relative dose intensity (RDI) in patients receiving chemotherapy for treatment of breast cancer. We aimed to determine factors associated with RDI of specific chemotherapy drugs in anthracycline- and/or taxane-based regimens. Women with a diagnosis of lymph node positive, invasive breast cancer who received neoadjuvant or adjuvant chemotherapy with either doxorubicin (DOX) + paclitaxel (PAC) or docetaxel (DOCE)-containing regimens at a single centerfrom2012 to2019 were included in this retrospective study. Age, race, comorbidities, height, weight, and chemotherapy regimen and dose were abstracted from the electronic health record. BMI was calculated using height and weight measured in clinic at the time initial chemotherapy orders were written and categorized according to US national guidelines (18.5 to < 25, 25 to < 30, and >30kg/m2). Presence of diabetes (DM) and hypertension (HTN) at time of diagnosis were determined by chart review. The oncologists’ initial chemotherapy orders (dose and duration) were used as the basis for RDI calculations. Cumulative actual dose received and duration of treatment were compared to planned dose and duration for individual chemotherapy drug and by regimen (DOX+PAC vs. DOCE). Associations between patient characteristics and RDI were evaluated in bivariate and multivariable analyses. A total of 230 women met the inclusion criteria, with 125 receiving a DOX+PAC regimen and 105 receiving a DOCE-based regimen. A higher percentage of women on DOX+PAC received >85% RDI compared to women receiving DOCE (80.8% vs 67.6%). Women aged 65+ years had lower median RDI [IQR] for DOCE than younger women (0.83 [0.67 - 0.98] vs 0.94 [0.84 - 1.00], p = 0.04), and a lower percentage in the older group received >85% RDI (35.3% vs 73.9%, p< 0.01). Median RDIs of PAC and DOX+PAC were lower for Black women than for White and Asian women (PAC: 0.91 [0.75 - 1.00] vs 1.00 [0.89 - 1.00], p = 0.02, DOX+PAC: 0.92[0.87-0.99] vs. 0.97 [0.91-1.00], p = 0.03), and the percent of Black women receiving >85% RDI of PAC was also lower (55.3% vs 77.6%, p = 0.01). BMI category was associated with median RDI for PAC (p= 0.03) and DOX+PAC (p = 0.01), with women in the >30kg/m2 category having the lowest median RDIs and PAC RDI >85% (p < 0.01). Median RDI of DOX+PAC was lower for women with DM (0.89 [0.84-0.92] vs. 0.96 [0.88-1:00], p = 0.03), and a lower percentage of women with DM received DOX RDI >85% compared to women without DM (66.7% vs 91.6%, p < 0.01). Median RDI was lower among women with HTN compared to women without for PAC (0.85 [0.73 - 1.00] vs 0.98 [0.83 - 1.00], p = 0.01) and DOX+PAC (0.91 [0.84 - 0.97] vs 0.97 [0.90 - 1.00], p = 0.01), and a lower percentage of women with HTN received >85% RDI for PAC (50.0% vs 73.3%, p = 0.01). Multiple logistic regression models adjusted for age (continuous), race, BMI (continuous), DM, and HTN had modestly improved predictive value compared to null models (McFadden’s R2 = 0.10 to 0.19); each year of increased age was associated with lower odds of RDI > 85% for DOX (OR [95% confidence interval] 0.91 [0.84-0.97], p = < 0.01), DOX+PAC (0.95 [0.90-0.99], p = 0.02), and DOCE (0.93 [0.88-0.97], p < 0.01), and DM with lower odds for DOX (0.26 [0.07-0.95], p = 0.04). Our findings of associations between increasing age, Black race, BMI, DM, and HTN and reduced RDI are consistent with prior research and present new data regarding associations between medical comorbidities and individual components of chemotherapy regimens. Citation Format: Heather Wopat, Annette Aldous, Adam Ciarleglio, Kendall Anderson, Kim Robien. Associations of age, body mass index, diabetes and hypertension with relative dose intensity among women receiving anthracycline- and/or taxane-based chemotherapy for invasive breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-16-09.