Abstract PS13-42: Locoregional recurrence in patients with early-stage triple-negative breast cancer receiving neoadjuvant systemic therapy: Patient characteristics and clinical outcomes
Authors: Haiderali Amin , Rhodes Whitney C. , Gautam Santosh , Huang Min , Sieluk Jan , Skinner Karen E. , Schwartzberg Lee S. 
Published: February 2021

Abstract
Background: Recurrence is common among patients with early-stage triple-negative breast cancer (ESTNBC). There is minimal real-world evidence describing the patient characteristics and clinical outcomes following recurrence among patients receiving neoadjuvant chemotherapy for ESTNBC. Methods: This retrospective, observational study aimed to describe the demographic and clinical characteristics and clinical outcomes in ESTNBC patients experiencing locoregional recurrence in the US community oncology setting in the Concerto HealthAI Definitive Oncology Dataset. Eligibility criteria included female sex, age 18+ years, diagnosis of stage II, IIIA or IIIB ESTNBC between 3/2008 and 3/2016, and receipt of definitive surgical resection following neoadjuvant systemic therapy. Descriptive methods were used to evaluate patient characteristics and treatment patterns in this population. Locoregional recurrence was defined as recurrence in the same breast and/or regional nodal recurrence as documented by the provider in the medical record. Results: Of 308 patients who received neoadjuvant treatment for ESTNBC, 27.3% patients (n=84) observed recurrence, within which 25.0% (n=21) were locoregional and 75.0% (n=63) were metastatic. All 21 patients with locoregional recurrence were 65 or younger, with mean age of 50.6 (SD 8.7) at initial diagnosis. They were primarily White (47.6%, n=10) or African American (42.9%, n=9). Over half of patients were stage II at initial diagnosis (61.9%, n=13), while 38.1% (n=8) were stage III. The majority had ductal histology (90.5%, n=19) and had Grade 3 tumors (90.5%, n=19). Of the 21 patients with locoregional recurrence, less than one-tenth (9.5%, n=2) had achieved pathologic complete response (pCR) prior to their recurrence, compared to 41.2% (n=127) of the 308 patients receiving neoadjuvant treatment. In terms of treatment following locoregional recurrence, two-thirds of patients received radiation therapy (66.6%, n=14) with median duration of 47.5 days. Over half of patients (57.1%, n=12) had mastectomy following recurrence, while 14.3% (n=3) had partial mastectomy (breast conserving surgery). Most patients (85.7%, n=18) received systemic chemotherapy after recurrence. Median duration of systemic therapy following locoregional recurrence was 108 days. Nearly one-half (47.6%, n=10) had a subsequent metastatic diagnosis and nearly one-third (28.6%, n=6) had a record of death. Median time from locoregional recurrence to metastatic diagnosis was 36.6 months, but median time from locoregional recurrence to death was not reached. Conclusions: Among patients who received neoadjuvant therapy for ESTNBC in the real-world setting, nearly 7% (n=21) experienced locoregional recurrence. Nearly one-fourth of those patients had a prior pCR which potentially suggests a higher risk of recurrence associated with ESTNBC patients. Chemotherapy was the mainstay of treatment following recurrence. Most patients also received radiation therapy and surgery, but despite those nearly one-half of the patients went on to have a subsequent metastatic diagnosis. This probably reflects the limitations of existing treatment modalities for ESTNBC patients. Future studies with a bigger sample size could confirm our findings. Our study provides some benchmark perspective to such future studies.
Citation Format: Amin Haiderali, Whitney C. Rhodes, Santosh Gautam, Min Huang, Jan Sieluk, Karen E. Skinner, Lee S. Schwartzberg. Locoregional recurrence in patients with early-stage triple-negative breast cancer receiving neoadjuvant systemic therapy: Patient characteristics and clinical outcomes [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS13-42.