Clinical characteristics and prognosis of postpartum breast cancer

• Published in: Breast cancer research and treatment Vol. 202; no. 2; pp. 275 - 286
• Main Authors: Paik, Pill Sun, Choi, Jung Eun, Lee, Seok Won, Lee, Young Joo, Kang, Young-Joon, Lee, Hyouk Jin, Bae, Soo Youn
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2023; Springer; Springer Nature B.V
• Subjects: Breast - pathology; Breast cancer; Breast Neoplasms - diagnosis; Breast Neoplasms - epidemiology; Breast Neoplasms - therapy; Cancer; Cancer patients; Cancer research; Chemotherapy; Clinical Trial; Diagnosis; ErbB-2 protein; Estrogen; Estrogen receptors; Female; Health aspects; Humans; Medical colleges; Medical prognosis; Medicine; Medicine & Public Health; Menopause; Metastases; Metastasis; Multivariate analysis; Oncology; Oncology, Experimental; Patients; Postpartum; Postpartum Period; Progesterone; Prognosis; Receptor, ErbB-2 - metabolism; Receptors, Estrogen - metabolism; Receptors, Progesterone - metabolism; Retrospective Studies; Survival; Breast cancer; Prognosis; Delivery; Postpartum
• ISSN: 0167-6806; 1573-7217
• DOI: 10.1007/s10549-023-07069-w

Purpose Postpartum breast cancer (PPBC) is a not well-established subset of breast cancer, and only few studies address its poorer prognosis. However, previous studies show that PPBC is associated with worse outcome with higher rates of metastasis than in young women’s breast cancer (YWBC). We aimed to analyze the clinical characteristics and prognosis of PPBC based on the diagnosis period of PPBC. Methods We retrospectively reviewed 208,780 patients with breast cancer from the Korean Breast Cancer Society registry (KBCSR) database between January 2000 and December 2014. We included premenopausal women aged 20–50 years who underwent breast cancer surgery. The patients were classified by 5-year intervals according to the diagnosis period of breast cancer, from the first birth to the breast cancer diagnosis. Results Compared with patients in the other groups, patients diagnosed within postpartum 5 years (PPBC < 5 years) group were younger, had a more advanced stage, had lower estrogen receptor (ER) and progesterone receptor (PR) expression, and had a higher human epidermal growth factor receptor 2 (HER2) positive rate. Further, PPBC < 5 years group had a worse survival rate than the nulliparous and other groups (5-year cumulative survival: PPBC < 5 years group, 89%; nulliparous group, 97.3%; 5 ≤ PPBC < 10 years group, 93%). In the multivariate analysis, the PPBC < 5 years group was associated with a worse survival rate (hazard ratio 1.55, 95% confidence interval [CI] 1.148–2.094, p 0.004) after adjustment for age at diagnosis, breast cancer stage, ER and HER2 status, Ki-67 level, and chemotherapy. Conclusion Our findings indicated that patients diagnosed with breast cancer within the first 5 years after delivery had aggressive characteristics and a poor survival rate. It is important to elucidate the pathophysiology of PPBC and establish novel therapeutic strategies to improve the survival rate.