Abstract P2-16-33: Patient characteristics and real-world treatment patterns in patients with early-stage triple-negative breast cancer receiving neoadjuvant chemotherapy
Authors: Rhodes Whitney C , Gautam Santosh , Haiderali Amin , Huang Min , Sieluk Jan , Skinner Karen E , Schwartzberg Lee S 
Published: March 2020

Background: For patients with stage II-III early-stage triple-negative breast cancer (ESTNBC), either neoadjuvant or adjuvant administration of chemotherapy is recommended. There is limited evidence describing the real-world patient characteristics and treatment patterns among patients receiving neoadjuvant +/- adjuvant chemotherapy for ESTNBC.

Methods: We conducted a retrospective observational study to describe the demographic and clinical characteristics and treatment patterns in ESTNBC patients in the US community oncology setting. Eligibility criteria included female sex, age 18+, diagnosis of stage II, IIIA or IIIB ESTNBC between 3/2008 and 3/2016, receipt of definitive surgical resection, and neoadjuvant systemic therapy with or without adjuvant systemic therapy. Descriptive methods were used to compare demographic and clinical characteristics and treatment patterns among patients who received neoadjuvant systemic therapy only (Neo) versus patients who received neoadjuvant plus adjuvant systemic therapy (Neo+Adj).

Results: 308 patients were eligible for the study. There were 236 patients (76.6%) who received Neo, while 72 (23.4%) received Neo+Adj. Mean age was 52.1 (SD 11.3), with 86.4% (n=266) of patients 65 or younger. Patients were predominantly White (56.8%, n=175) followed by African American (35.7%, n=110). Demographic characteristics did not differ by treatment group.

The majority of patients were stage II at initial diagnosis (66.6%, n=205) and had ductal histology (93.5%, n=288). Over half of all patients (55.8%, n=172) had mastectomy; 44.2% (n=136) had breast conservation surgery. The majority of patients (79.5%, n=245) had no comorbid conditions and most (82.8%, n=255) had grade 3 tumors. Overall, 42.2% were peri/postmenopausal (n=130) at diagnosis. Distribution of stage at diagnosis was significantly different between groups (p=0.013). The pattern of findings suggests that the Neo group had earlier stage disease. Over one-third of patients with Neo were stage IIA at diagnosis (36.0%, n=85). Nearly one-fifth of patients with Neo+Adj were stage IIIB at diagnosis (19.4%, n=14), compared to 8.5% of patients receiving Neo (n=20). A significant difference in surgery type by treatment group was observed (p=0.035). Patients with Neo had a lower rate of mastectomy (52.5%, n=124) compared to Neo+Adj (66.7%, n=48), likely as a result of earlier stage disease at presentation.

Among the Neo group, the most common neoadjuvant regimen was cyclophosphamide, doxorubicin and paclitaxel (59.3%, n=140), followed by cyclophosphamide, doxorubicin and docetaxel (14.4%, n=34). Most (85.2%, n=201) patients receiving Neo received one regimen in the neoadjuvant setting, while 13.1% (n=31) received two regimens.

Among the Neo+Adj group, the most common neoadjuvant regimens were cyclophosphamide, doxorubicin and paclitaxel (38.9%, n=28) and cyclophosphamide with doxorubicin (23.6%, n=17), while the most common adjuvant regimens were paclitaxel (22.2%, n=16) and capecitabine (12.5%, n=9). Most (70.8%) patients receiving Neo+Adj received one neoadjuvant regimen followed by a different adjuvant regimen.

Conclusions: In this sample of real-world patients with ESTNBC, the majority of patients were diagnosed with stage II disease, with limited or no comorbidities. This evaluation of treatment patterns confirmed that real-world treatment is limited to chemotherapy, which is consistent with the NCCN guidelines.

Citation Format: Whitney C Rhodes, Santosh Gautam, Amin Haiderali, Min Huang, Jan Sieluk, Karen E Skinner, Lee S Schwartzberg. Patient characteristics and real-world treatment patterns in patients with early-stage triple-negative breast cancer receiving neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P2-16-33.