To analyze the clinicopathologic characteristics, diagnosis and treatment of pregnancy-associated breast cancer (PABC) patients.

We retrospectively analyzed the medical records of 85 patients with PABC who were admitted to the Sun Yat-sen University Cancer Center from January 2012 to January 2019. Their clinicopathological characteristics, diagnosis and treatment were evaluated. The Kaplan-Meier method was used for survival analysis. The median disease-free survival (DFS) of early-stage PABC patients (without distant metastasis in primary diagnosis) and the median progression-free survival (PFS) of advanced PABC patients (with distant metastasis in primary diagnosis) were further estimated.

The age of 85 patients was 33 (30, 36) years old. The body mass index was 22.5 (20.5, 24.0) kg/m². Four patients had a family history of breast cancer. Totally 48.2%(41/85) of patients were diagnosed during pregnancy and the gestation was 28 (19, 32) weeks; 51.8%(44/85) of patients were diagnosed within 1 year after delivery [4 (1, 8) months postpartum]. In terms of pathology, there were 67 cases of invasive ductal carcinomas, 4 invasive lobular carcinomas, 1 mucinous carcinoma, 6 mixed carcinomas, 4 other pathological types and 3 unknown. There were 38 cases of histological grade 3, 26 grade 2, and 21 unknown. A total of 54 patients were ER/PR positive and 30 patients were HER-2 positive. As for molecular typing, there were 25 patients with luminal B1 subtype, 22 triple negative subtype, 21 luminal B2 subtype, 9 HER-2 positive subtype, 5 luminal A subtype, and 3 unknown subtypes. The number of patients at TNM stage Ⅰ, Ⅱ, Ⅲ and Ⅳ was 10, 27, 27 and 16, and other 5 patients had unknown stage. Fifty-nine patients were diagnosed by physical examination + ultrasound + fine needle biopsy. Totally 74 patients underwent surgery, including 59 patients with modified radical mastectomy, 8 with lumpectomy + axillary lymph node dissection, 3 with total mastectomy + sentinel lymph node biopsy, and 4 with lumpectomy + sentinel lymph node biopsy. Only 37 patients received chemotherapy, 22 received chemotherapy combined with endocrine therapy, 11 received chemotherapy, targeted therapy and endocrine therapy, 11 received chemotherapy combined with targeted therapy and 3 received endocrine therapy only; the treatment of one patient was unknown. Most of chemotherapy regimens were based on anthracyclines and taxanes. Forty-five patients underwent radiotherapy after delivery. Among the patients diagnosed during pregnancy, 27 received no treatment during pregnancy, 10 received neoadjuvant chemotherapy regimens and 4 patients underwent surgery. The follow-up time of 85 patients was 23.6 (12.8-46.4) months. Among them, 7 cases (8.2%) were lost to follow-up. The median DFS of 62 early stage PABC patients was 36.0 months (95%CI: 29.2-42.8 months), while the median PFS of 16 advanced breast cancer patients was 14.5 months (95%CI: 5.0-23.9 months).

Surgery and chemotherapy are relatively safe treatment options for PABC patients.