Candice N. Thompson

Supplementary Figure 2. Time from Diagnosis to minimum ALC

Background:Low absolute lymphocyte count (ALC) is associated with breast cancer–specific mortality (BCM) and overall mortality (OM) in non-Hispanic (NH) White women with triple-negative breast cancer (TNBC). However, little is known about the relationship between ALC and BCM or OM in other breast cancer subtypes, racial, or ethnic groups. In this study, we investigated the association of ALC with BCM and OM by breast cancer subtype and evaluated for modification by race or ethnicity. Methods:We used the Oncoshare database, linking data from electronic medical records of academic and community institutions to data from the California Cancer Registry, to identify women diagnosed with stage I to III breast cancer in 2000 to 2017 who had a post-diagnosis ALC within 5 years. We used logistic regression to identify factors associated with low ALC (<1 K/μL) and Cox models to evaluate the association of minimum ALC (minALC) after diagnosis with BCM and OM. Results:In 11,669 women, low ALC was associated with neutropenia, chemotherapy receipt, advanced stage, more comorbidities, and aggressive tumor features (all P ≤ 0.001). Lower minALC was associated with higher OM [hazard ratio (HR) = 0.96 per 1 K/μL increase; 95% confidence interval (CI), 0.93–0.99], most strongly in TNBC (HR = 0.73; 95% CI, 0.59–0.91). Race and ethnicity modified associations of minALC with BCM and OM (interaction P < 0.001), more strongly in NH Black and Hispanic than NH White women. Conclusions:Low peripheral ALC was associated with higher OM in women with estrogen and/or progesterone receptor–positive, human epidermal growth factor receptor 2 (HER2)–negative breast cancer or TNBC. Impact:Low ALC is more strongly associated with OM and BCM in women from minoritized racial and ethnic groups.

Supplementary Figure 1. Consort Diagram

Supplementary Figure 3. Low ALC by Race, Ethnicity and time windows

Supplementary Figure 4. Low ALC by time window

Supplementary Table 11. Association between minALC and Mortality, by Race and Ethnicity

Supplementary Table 3. Race and Ethnicity-specific Cox Hazard Ratios fro minALC and mortality

Supplementary Table 1. Baseline patient characteristics with and without ALC

Supplementary Table 10. Association between minALC and Mortality, by Breast Cancer Subtype.

Supplementary Table 2. Cox Hazard Ratios for minALC and Mortality by Landmark Windows