A full-term pregnancy protects against the development of breast cancer later in life, but shortly after pregnancy the risk of breast cancer increases temporarily, with a peak in risk 5–7 years after delivery. In addision, several epidemiological studies have revealed that the recent parity before breast cancer diagnosis has been associated with worse outcome, with a peak in risk of death within 2 years after delivery. The objective of this study was to demonstrate the impact of recent parity on the clinicopathological tumor feature and patient outcome.Methods
We retrospectively analyzed a cohort of 526 cases of invasive breast cancer diagnosed at <45 years of age from 2000 to 2007. Patient characteristics including reproductive history were obtained from an initial routine questionnaire and a medical record, and we defined as Group A (within 2 years post-partum of last childbirth, n = 37), Group B (between 3 and 5 years post-partum, n = 59), Group C (more than 5 years post-partum, n = 181), and Group N (nulliparous, n = 249). Clinicopathological characteristics were obtained from pathology records. Survival curves were derived from the Kaplan–Meier method. The hazard ratios (HR) for death were estimated using Cox proportional hazards models.Results
Compared with group N, women in group A had more tumors involving regional lymph nodes (49% versus 26%), more stage III and IV disease (24% versus 14%, 11% versus 3%), more histological grade 3 (73% versus 47%), and more triple negative (30% versus 15%) and HER2-enriched (19% versus 7%) subtypes. The median follow-up time was 6.3 years (range: 0.1–11.7) during which there were 90 deaths. The Kaplan–Meier 5-year survival probability was 64.3% for group A, 79.3% for group B, 88.2% for group C and 90.6% for group N, respectively. Compared with group N, group A had >2.6-fold higher risk for death adjusted by age at diagnosis and AJCC stage (HR 2.58, 95% CI: 1.43–4.67), but there were no significant difference in the risk when compared with groups B and C.Conclusions
Women with recent parity were characterized by worse clinicopathological tumor features compared with nulliparous women. Women with recent parity had an increased risk for death within 2 years of diagnosis, but the risk did not remain more than 5 years post-partum. We need further studies to elucidate underlying biology.