Abstract PO1-11-08: Late effects of breast cancer treatment among long term breast cancer survivors in the Carolina Breast Cancer Study
Authors: Yarosh Rina , Nichols Hazel , Hirschey Rachel , Kent Erin , Carey Lisa , Troester Melissa , Butler Eboneé 
Published: May 2024

Background: Improved precision in breast cancer treatment has contributed to better overall survival. Intensive breast cancer treatments may have long-term impacts on survivor quality of life. Survivors may experience late effects including lymphedema, peripheral neuropathy, and cardiotoxicity from surgery, radiation, or chemotherapy. Estimates of the long-term burden of chronic breast cancer related conditions are important for managing the care of survivors.

Methods: The Carolina Breast Cancer Study 3 is a population-based study of female breast cancer survivors diagnosed from 2008 to 2013 in North Carolina. Black and younger (&lt; 50 years at diagnosis) women were oversampled. We calculated the cumulative prevalence of self-reporting of ever being diagnosed with lymphedema, peripheral neuropathy, or cardiac/heart problems as a result of breast cancer treatment over a 10-year follow-up period. Prevalence differences (PD) and 95% confidence intervals (CI), adjusted for age and race, were calculated to describe the differences in late effects in relation to patient characteristics (including latent class SES and access to care barriers). Additionally, we assessed racial disparities in the prevalence of late effects.

Results: We included 1133 women who completed follow-up assessments at a mean of 11.2 years (SD=0.5) post diagnosis. The sample was predominately diagnosed with early stage (89.2%) and ER+ disease (75.2%). Treatments included lymph node removal ( &gt;5 lymph nodes 57.9%), anthracycline chemotherapy (34.1%), taxane chemotherapy (60.3%), breast conserving surgery (58.7%), and mastectomy (41.0%). The prevalence of self-reporting lymphedema was 39.9% and was more common among younger (&lt; 50 vs ≥50 PD: 10.2%, CI 4.7-15.7) and Black women (vs. White PD: 19.1%, CI 13.5-24.7), and those with fewer access to care barriers (vs more PD: -19.5%, CI -31.1- -8). The prevalence of peripheral neuropathy was 64.9% and was more common among younger (&lt; 50 vs ≥50 PD: 5.6%, CI 0.2-11.0) and Black women (vs. White PD: 16.5%, CI 11.1-21.9), and those of lower SES (high vs low PD: -11.7%, CI -17.6- -5.7). Rural survivors were less likely to report peripheral neuropathy (PD: -9.7%, CI: -17.5- -2.0). Cardiac problems were reported in 16.7% of the sample and were more common among those of high SES (vs. low PD: -7.7%, CI -12.5, -3.0).

All three late effects were associated with higher stage disease, ER+ disease, number of lymph nodes removed, anthracycline chemotherapy, and taxane chemotherapy. Both lymphedema and peripheral neuropathy were associated with mastectomy. Lymphedema was associated with trastuzumab use. Peripheral neuropathy was associated with recurrence.

In stratified analyses by ER status, Black women were 13.7-28.8% more likely to have lymphedema in both ER+ and ER- disease (ER+ PD Black vs. White: 13.7%, CI 7.9-20.3; ER- PD Black vs. White: 28.8%, CI 18.3-39.3). Similar patterns were seen in analyses stratified by number of lymph nodes removed and by taxane chemotherapy. Other associations were not suggestive of racial disparities; with one exception. Black women were more likely to have cardiac problems at both high and low levels of SES (High Black vs White PD: 2.8%, CI -3.0, 8.6; low Black vs White PD: -7.0%, CI -15.2, 1.2).

Conclusions: This study identified patient characteristics associated with an increased burden of late effects. Black and younger women experience a higher burden of lymphedema and peripheral neuropathy. Disease stage, ER status, lymph nodes removed, and chemotherapy received were associated with a higher prevalence of all three late effects and this is consistent with the observation that the burden of late effects increases with factors associated with more advanced stage of disease. Improved surveillance and prevention measures for breast cancer late effects can help improve survivorship care.

Citation Format: Rina Yarosh, Hazel Nichols, Rachel Hirschey, Erin Kent, Lisa Carey, Melissa Troester, Eboneé Butler. Late effects of breast cancer treatment among long term breast cancer survivors in the Carolina Breast Cancer Study [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 PO1-11-08.