Understanding Trends in Incidence and Management of Pregnancy-Associated Breast Cancer in a National Sample Using Claims Data.

Abstract

Background and objectives: Breast cancer incidence in young women is increasing globally. Here, we examine trends in incidence, management, and reconstruction for pregnancy-associated breast cancer (PABC) in women 18-45.

Methods: Females aged 18-45 with breast cancer between 2007 and 2021 were identified in the Merative MarketScan Commercial and Multi-State Medicaid Databases. We analyzed trends in incidence of PABC, treatments, and latency to treatments for PABC versus non-PABC.

Results: A total of 1189 patients with PABC and 36 683 with non-PABC were included. Over the study period, the proportion of breast cancer cases classified as PABC increased (2.36% of cases from 2007 to 2009, to 3.94% from 2019 to 2021; p < 0.001). Patients with PABC experienced higher rates of neoadjuvant chemotherapy, mastectomy, trastuzumab, and ovarian suppression therapy than patients with non-PABC, and lower rates of adjuvant radiation and breast conserving surgery (p ≤ 0.001). PABC status did not independently predict increased latency from diagnosis to tumor resection surgery when controlling for receipt of neoadjuvant chemotherapy (p = 0.154). Patients with PABC experienced comparable rates of delayed or immediate implant and autologous reconstruction as patients with non-PABC, but experienced increased latency to delayed implant reconstruction (p < 0.001).

Conclusions: PABC rates are increasing among women 45 and younger. Patients with PABC experience differences in types of medical/surgical treatments received and timing of post-mastectomy reconstruction.