Abstract P6-03-04: Ipsilateral infusions are not associated with increased risk of breast cancer-related lymphedema in patients enrolled in a prospective screening program

Abstract BACKGROUND: Patients treated for breast cancer (BC) who are at risk of breast cancer-related lymphedema (BCRL) have been instructed for decades to avoid venipuncture, injections and infusions in the extremity ipsilateral to BC treatment. These instructions are given in theory to prevent BCRL development, despite lack of supporting data. Given fear of BCRL is high amongst the population at risk, it has been found that patients heed this advice regardless of level of BCRL risk. It has been previously found that there is no association between blood draws or injections in the ipsilateral arm and increases in arm volume in patients treated for BC and screened for BCRL. Despite these findings, risk of BCRL associated with the most invasive of BC treatments, infusions in the ipsilateral arm, has not been examined. As patients with BC require ongoing invasive medical procedures, data would inform patient care and drive clinical practice guidelines during and after BC treatment. PURPOSE: The purpose of this study was to determine whether patients treated for breast cancer who receive one or more infusions in the arm ipsilateral to BC treatment are at higher risk of BCRL than those who do not receive ipsilateral infusions. METHODS: From 2005 to 2021, 2049 patients treated for BC were enrolled in a prospective BCRL screening trial and screened from preoperative baseline through last follow-up. Screening included objective arm volume measurements via perometry; relative volume change (RVC) increase ≥10% from preoperative baseline >3 months postoperatively was used to define BCRL. Infusions data were collected directly from the electronic medical record and all postoperative infusions were included in data analysis. Patients were censored at cancer recurrence. Infusions data included route, laterality, date and substance infused. Demographic and clinical information were obtained through medical record review. Marginal structural models were used to estimate the hazard of BCRL attributable to any (vs. no) ipsilateral infusion. Time-varying inverse-probability weights were used to account for time-varying confounding by RVC and earlier adjuvant infusions, and adjusted for baseline confounding by baseline BMI, axillary lymph node dissection (ALND), regional lymph node radiation (RLNR), neoadjuvant chemotherapy, and number of neoadjuvant ipsilateral infusions. RESULTS: The eligible cohort included 2018 patients. 240 patients received at least one ipsilateral infusion; 651 did not receive ipsilateral infusions; 1,127 did not receive infusions. Patients who received ipsilateral infusions received a median of 2 (interquartile range (IQR) 1, 3) ipsilateral and 8 (IQR 4, 15) total infusions. 681 (34%) patients received adjuvant chemotherapy infusions; the most frequent adjuvant regimens received included ACT (314 patients, 16%); TC (162 patients; 8.0%); and ACTH (±P) (47 patients, 2.3%). Of those who received any ipsilateral infusions, 77% had chemotherapy drugs infused, compared to 84% of participants who did not have ipsilateral infusions. Fluids, antacids, and antihistamines were the most common non-chemotherapy infusions. Patients underwent BCRL screening over a median of 5 visits (IQR 3,8) with a median follow-up of 56 months (IQR 31, 90 months). There was no significant difference in BCRL risk between patients who received at least one ipsilateral infusion and those who did not receive ipsilateral infusions (HR, 0.85; p=0.60). CONCLUSIONS: Infusions in the at-risk arm were not associated with increased risk of BCRL in this cohort of 2018 patients at risk of and prospectively screened for BCRL. Citation Format: Cheryl L. Brunelle, Amanda W. Jung, Louisa H. Smith, Kayla Daniell, Maria S. Asdourian, Loryn K. Bucci, Brooke Juhel, Elizabeth K. Hausman, George E. Naoum, Alphonse G. Taghian. Ipsilateral infusions are not associated with increased risk of breast cancer-related lymphedema in patients enrolled in a prospective screening program. [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-03-04.