P2-12-21: Impact of Recent Parity on Histopathological Tumor Features and Outcome of Young Women with Breast Cancer.
Authors: Nagatsuma AK , Shimizu C , Tsuda H , Saji S , Hojo T , Sugano K , Fujiwara Y 
Published: June 2012

Abstract
Background
Younger age has been associated with worse outcome in breast cancer patients (pts) and recent parity has been epidemiologically identified as worse prognostic factor among women with breast cancer. The objective of this study was to explore potential factors associated with worse prognosis in young breast cancer pts, and to demonstrate the impact of parity on the histopathological tumor feature and patient outcome.
Materials and Methods: We retrospectively analyzed 634 early breast cancer pts younger than 45 years old who underwent surgery between 2000 and 2009. For statistical analysis, Pearson's and Fisher's exact test were used. Survival analysis was performed only for pts diagnosed before 2006 in order to obtain a minimum follow up 5 years.
Results: 108 women were diagnosed within 5 years since last parity (Group A), 216 were diagnosed &gt; 5 years since last parity (Group B) and 310 were nulliparous (Group C). Median age at diagnosis was 37 (range 26–44), 41 (range 32–44), and 38.5 (range 22–44) and family history (FH) of breast and/or ***ovarian cancer within second degree was found in 23, 22, and 23% of the pts in Groups A, B, and C, respectively. In Groups A, B and C, clinical stage was III in 22, 10 and 12% (p= .025), ER was positive in 65, 69 and 70% (p= .650), PgR was positive in 64, 75 and 74% (p= .057), and HER2 was positive in 25, 14 and 14% (p=.017), respectively. Tumors in Group A had higher histological grade (grade 3: 60/44/47%, p=.019), higher nuclear grade (grade 3: 61/47/48%, p=.036) and more lymph vessel invasion (61/52/45%, p=.015) compared to those in Groups B and C, respectively. Median follow up time was 85.1 months (range 1.8−137.1 months) during which there were 61 deaths. In univariate analysis, age and FH were not correlated with overall survival (OS). OS in Group A was significantly lower than in Group B (hazard ratio (HR) 3.51, 95% confidential interval (CI) 1.80−6.84, p&lt;.001) and in Group C (HR 2.42, 95%CI 1.36−4.29, p=.002), while OS did not differ significantly between Groups B and C. In the pts without FH, the HR of cancer death was more pronounced in Group A than in Group B (HR 4.25, 95%CI 1.97−9.14, p&lt;.001) or Group C (HR 2.67, 95%CI 1.43−5.01, p=.002), while there was no significant difference among the groups in pts with FH. In multivariate analysis among the pts without FH, lymph vessel invasion (HR 4.51, 95%CI 1.89−10.76, p=.001), Group A women (HR 2.28, 95%CI 1.25−4.17, p=.007), histological grade 3 (HR 2.72, 95%CI 1.28−5.77, p=.009), PgR negativity (HR 2.23, 95%CI 1.19−4.18, p=.013) and clinical stage II and III (HR 2.92, 95%CI 1.04−8.21, p=.04) were significantly associated with poor prognosis, adjusting for age.
Conclusion: Recent parity was associated with worse histopathological features in breast cancer of women younger than 45. It was also associated with worse outcome, especially among pts without FH. Recent parity seems to be a confounding factor for the worse outcome in young breast cancer patients, which justifies further studies to elucidate underlying biology.
Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-12-21.