TY - JOUR
T1 - Association of parity and time since last birth with breast cancer prognosis by intrinsic subtype
AU - Sun, Xuezheng
AU - Nichols, Hazel B.
AU - Tse, Chiu Kit
AU - Bell, Mary B.
AU - Robinson, Whitney R.
AU - Sherman, Mark E.
AU - Olshan, Andrew F.
AU - Troester, Melissa A.
N1 - Funding Information:
This work was supported by grants from the NCI (U01-ES019472 and P50CA058223; to M.A. Troester) and by the Development Award and the University Cancer Research Fund from the University of North Carolina at Chapel Hill (to M.A. Troester). This work was also supported (in part) by a grant from the NCI (K01CA172717; to W.R. Robinson).
Publisher Copyright:
©2015 AACR.
PY - 2016/1
Y1 - 2016/1
N2 - Background: Parity and time since last birth influence breast cancer risk and vary by intrinsic tumor subtype, but the independent effects of these factors on prognosis have received limited attention. Methods: Study participants were 1,140 invasive breast cancer patients from phases I and II of the population-based Carolina Breast Cancer Study, with tissue blocks available for subtyping using immunohistochemical markers. Breast cancer risk factors, including pregnancy history, were collected via in-person interviews administered shortly after diagnosis. Vital status was determined using the National Death Index. The association of parity and birth recency with breast cancer-specific and overall survival was assessed using Cox proportional hazards models. Results: During follow-up (median = 13.5 years), 450 patients died, 61% due to breast cancer (n = 276). High parity (3+ births) and recent birth (<5 years before diagnosis) were positively associated with breast cancer-specific mortality, independent of age, race, and selected socioeconomic factors [parity, reference = nulliparous, adjusted HR = 1.76; 95% confidence interval (CI) = 1.13-2.73; birth recency, reference = 10+ years, adjusted HR = 1.29; 95% CI, 0.79-2.11]. The associations were stronger among patients with luminal tumors and those surviving longer than 5 years. Conclusions: Parity and recent birth are associated with worse survival among breast cancer patients, particularly among luminal breast cancers and long-term survivors. Impact: The biologic effects of parity and birth recency may extend from etiology to tumor promotion and progression.
AB - Background: Parity and time since last birth influence breast cancer risk and vary by intrinsic tumor subtype, but the independent effects of these factors on prognosis have received limited attention. Methods: Study participants were 1,140 invasive breast cancer patients from phases I and II of the population-based Carolina Breast Cancer Study, with tissue blocks available for subtyping using immunohistochemical markers. Breast cancer risk factors, including pregnancy history, were collected via in-person interviews administered shortly after diagnosis. Vital status was determined using the National Death Index. The association of parity and birth recency with breast cancer-specific and overall survival was assessed using Cox proportional hazards models. Results: During follow-up (median = 13.5 years), 450 patients died, 61% due to breast cancer (n = 276). High parity (3+ births) and recent birth (<5 years before diagnosis) were positively associated with breast cancer-specific mortality, independent of age, race, and selected socioeconomic factors [parity, reference = nulliparous, adjusted HR = 1.76; 95% confidence interval (CI) = 1.13-2.73; birth recency, reference = 10+ years, adjusted HR = 1.29; 95% CI, 0.79-2.11]. The associations were stronger among patients with luminal tumors and those surviving longer than 5 years. Conclusions: Parity and recent birth are associated with worse survival among breast cancer patients, particularly among luminal breast cancers and long-term survivors. Impact: The biologic effects of parity and birth recency may extend from etiology to tumor promotion and progression.
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U2 - 10.1158/1055-9965.EPI-15-0864
DO - 10.1158/1055-9965.EPI-15-0864
M3 - Article
C2 - 26545404
AN - SCOPUS:84955264808
VL - 25
SP - 60
EP - 67
JO - Cancer Epidemiology Biomarkers and Prevention
JF - Cancer Epidemiology Biomarkers and Prevention
SN - 1055-9965
IS - 1
ER -