Abstract PO4-11-04: Early Discontinuation of Adjuvant Chemotherapy in Older Adults with Early Breast Cancer: Results from the Prospective Multicenter HOPE Study
Authors: Ji Jingran , Sun Canlan , Freedman Rachel , Cohen Harvey , Klepin Heidi , Tew William , Moy Beverly , Chapman Andrew , Wildes Tanya , Dotan Efrat , Magnuson Allison , O'Connor Tracey , Fenton Mary Anne , Kim Heeyoung , Katheria Vani , Gross Cary , Muss Hyman , Sedrak Mina 
Published: May 2024

Background: Older adults with early breast cancer (EBC) treated with adjuvant chemotherapy frequently experience severe toxicities. As a result of such toxicities, many older adults do not complete all planned chemotherapy cycles (i.e., discontinue chemotherapy early). Early discontinuation may increase the risk of recurrence and decrease survival. However, aging is heterogeneous and identifying which older adult is at risk of early discontinuation before starting chemotherapy remains a key knowledge gap. To fill this gap, we examined the incidence, reasons, and risk factors for early discontinuation of adjuvant chemotherapy in older adults with EBC.

Methods: This is a post-hoc analysis of 501 older adults (age&gt;65) with EBC enrolled in the Hurria Older PatiEnts (HOPE) with Breast Cancer Study (NCT01472094, R01AG037037), a prospective multicenter study. All participants were treated with neo/adjuvant chemotherapy. Prior to initiating chemotherapy, participants completed survey measures on sociodemographic, clinical, and geriatric assessment characteristics. The primary outcome was early discontinuation (yes/no; yes, defined as failure to complete all planned chemotherapy cycles). Multivariable logistic regression with stepwise selection was used to evaluate the association between baseline variables (demographic, clinical, geriatric assessment) and early discontinuation.

Results: A total of 501 participants (median [range] age, 70 [65-86] years and mean [SD] physician-rated KPS 93 [9.3]) were included. One hundred and thirteen (23%) had early discontinuation. Among participants with early discontinuation, 69% discontinued treatment within the last 3 cycles. In bivariate analysis, early discontinuation was associated with older age (continuous), higher stage (II/III), use of non-TC regimens (anthracycline-based or trastuzumab-based), lower albumin level (continuous), a history of diabetes, ≥1 fall in the last 6 months, and lower activities of daily living (ADL) score (&lt; 85). Multivariable stepwise logistic regression analysis identified that ≥1 fall in the last 6 months, ADL score &lt; 85, and regimen were associated with early discontinuation at p &lt; 0.05. In the final model, after accounting for clinically meaningful variables including age, stage, and regimen, the results for falls (odds ratio [OR] = 2.04, 95% CI: 1.10-3.78, p=0.02) and ADL (OR=2.10, 95% CI: 1.32-3.34, p=0.002) remained highly significant. Compared to participants with no falls and ADL scores &gt;85, participants with who reported both falls and an ADL score &lt; 85 prior to initiation of chemotherapy had more than 4-fold increased odds of early discontinuation (Table).

Conclusion: In this cohort of older adults with EBC, nearly 1 in 4 older patients initiated neo/adjuvant chemotherapy but did not complete all planned chemotherapy cycles. Older patients at risk for early discontinuation should be identified and targeted upfront before initiating chemotherapy.

Table. Multivariable associations between falls, ADL score, and early discontinuation. *Adjusted for age (continuous), stage (I vs. II/III), and regimen (anthracycline based + no trastuzumab vs. non-anthracycline based + no trastuzumab vs. anthracycline based + trastuzumab vs. platinum/CMF + trastuzumab vs. taxol only + trastuzumab vs. other). ** Five patients missing fall information. Two patients missing ADL score.

Citation Format: Jingran Ji, Canlan Sun, Rachel Freedman, Harvey Cohen, Heidi Klepin, William Tew, Beverly Moy, Andrew Chapman, Tanya Wildes, Efrat Dotan, Allison Magnuson, Tracey O'Connor, Mary Anne Fenton, Heeyoung Kim, Vani Katheria, Cary Gross, Hyman Muss, Mina Sedrak. Early Discontinuation of Adjuvant Chemotherapy in Older Adults with Early Breast Cancer: Results from the Prospective Multicenter HOPE 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 PO4-11-04.