Association Between Postpartum Breast Cancer Diagnosis and Metastasis and the Clinical Features Underlying Risk

Key Points Question Is there an increased risk for metastasis of breast cancers that are diagnosed in young women post partum that extends beyond 5 years from the last childbirth, and what association do standard clinical prognostic factors have with metastatic risk in these young women when categorized by parity? Findings In a cohort study of 701 women 45 years or younger with breast cancer, those with stage I or II cancer diagnosed up to 10 years post partum had an increased risk for distant metastasis, with both estrogen receptor–positive and estrogen receptor–negative disease significantly affected. Meaning Postpartum status may be a prognostic indicator in young women with breast cancer and should be routinely identified, as up to 45% of women 45 years or younger with breast cancer fall into this category and could be at increased risk for metastasis.