Abstract C31: Racial/ethnic differences in cancer survivorship: The example of breast cancer-related lymphedema severity

Introduction: Breast-cancer related lymphedema (BCRL) is a persistent adverse outcome of cancer treatment that affects the physical health and quality of life of up to 1 in 3 of the 2.9 million breast cancer survivors in the US. For those with BCRL, known predictors of progression include BMI, type of surgery and radiation treatment, each of which is independently associated with race/ethnicity. Observational studies have found that Black/African-American women are more likely than Whites to develop BCRL, but no studies have explored the association of race/ethnicity with BCRL severity. Method: The WISER Survivor Trial has collected baseline data from 149 overweight (BMI≥25) women with upper body BCRL (61% White; 39% African-American). Ordinal logistic regression modeling was used to explore the associations of known predictors of lymphedema progression and race/ethnicity with lymphedema grade (0-3). Results: In univariate analysis, higher age at breast cancer surgery, being African-American, and having had chemotherapy or radiation therapy were significantly associated with higher lymphedema grade. Multivariate analysis revealed that race mediates the relationship between BMI and lymphedema grade such that being African-American AND having an elevated BMI is associated with higher lymphedema grade while elevated BMI is not associated with higher lymphedema grade among White women, such that at equivalent BMI, African-American women were 20% more likely to have a higher lymphedema severity (OR=1.20 [1.00, 1.44]; p=0.043). Discussion: These findings point to a need for clinicians to be aware of increased risk of lymphedema for overweight African-American female breast cancer survivors. The cause of the observed interaction of African-American race/ethnicity and BMI on lymphedema severity remains to be elucidated. Previous studies have observed a relationship of higher lymphedema grade with higher costs to care for the condition, as well as worse functional ability of the upper body. Therefore, increased odds of higher lymphedema grade among African-American women with elevated BMI could contribute to a meaningful difference in the burden of breast cancer survivorship for this underserved minority population. To further elucidate this relationship, prospective collection on health-care costs for breast cancer survivors with lymphedema is warranted. This work has implications to affect care for and quality of life of up to 1 in 3 of the 2.9 million breast can