The impact of obesity on receipt of adjuvant chemotherapy for breast cancer in the National Comprehensive Cancer Network (NCCN) centers

Abstract

Disparities in the receipt of adjuvant chemotherapy for early stage breast cancer is an important factor influencing mortality. We investigated whether greater body mass index (BMI) decreases receipt of adjuvant chemotherapy among women with operable breast cancer. In the NCCN breast cancer outcomes database, we identified women age ≤70 with newly diagnosed stage I, II or III breast cancer between 1997 and 2007, for whom use of adjuvant chemotherapy was classified as either standard-of-care or discretionary based on their clinical characteristics. Body mass index was assessed in categories (<18.5 kg/m2 [underweight], 18.5 to <25 kg/m2 [normal], 25 to <30 kg/m2 [overweight], 30 to 39kg/m2 [obese], ≥40 kg/m2 [extreme obese]). Multivariable logistic regression analysis was used to examine the association between BMI and receipt of chemotherapy in each classification group. 9,527 women were eligible for the study; 40% normal weight or less; 31% overweight; 24% obese; and 5% extremely obese. In multivariable analysis, there was no significant association between BMI and receipt of chemotherapy in either classification group. Among women for whom chemotherapy would be considered standard-of-care, older age (p<.001), comorbidity (p<.001), and non-Hispanic black ethnicity (p=.002) were associated with a lower likelihood of receipt of chemotherapy; however, the effect of ethnicity was not mediated by obesity. Among women treated for operable breast cancer in the NCCN centers, BMI had no impact on receipt of adjuvant chemotherapy and did explain the lower likelihood of chemotherapy among non-Hispanic black patients. Further investigation is needed into other factors that contribute to patient disparities in the receipt of chemotherapy in major academic centers.

Variations in the body mass index in Brazilian women undergoing adjuvant chemotherapy for breast cancer

“…This percentage is slightly higher than the 31% overweight reported in a study including 9,527 patients diagnosed with breast cancer from 1997 to 2007 at participating centers of the National Comprehensive Cancer Network 21 . A Korean study found differences in the BMI between East Asian and Western women 22 .…”

Weight Change and Survival after Breast Cancer in the After Breast Cancer Pooling Project

“…Women with existing comorbid conditions are known to receive less extensive breast cancer treatment (43), and since chemotherapy is associated with weight gain (44–47), the lack of weight gain or weight loss may be an indicator for treatment that is not the standard of care (48). Additionally, women with comorbid conditions at the time of breast cancer diagnosis are more likely to be subsequently hospitalized for chemotherapy toxicity, infection and fever, neutropenia, anemia, all of which increase the risk of weight loss (49) and decrease survival.…”

Obesity and Risk of Breast Cancer Mortality in Hispanic and Non-Hispanic White Women: The New Mexico Women's Health Study

“…[43][44][45] There are concerns that obese women could potentially experience toxic effects if chemotherapy doses were based on their actual body weight. 43 It also has been suggested that diabetic women may receive less aggressive treatment because of their diabetes-related complications 11,46 ; 38% of the obese breast cancer cases were diabetic.…”