Abstract 4127: A prospective study of breast cancer prognosis in Kaiser Permanente Northern California: Cohort description and initial findings from the Pathways Study
Authors: Kushi Lawrence H. , Kwan Marilyn L. , Ergas Isaac J. , Laurent Cecile A. , Munneke Julie R. , Roh Janise M. , Greenlee Heather , Hong Chi-Chen , Keegan Theresa H. , Hershman Dawn L. , Kutner Susan E. , Lee Marion M. , Mandelblatt Jeanne , Neugut Alfred I. , Reynolds Peggy , Shariff-Marco Salma , Tang Li , Yao Song , Barlow Janice , Gomez Scarlett Lin , Wiencke John K. , Ambrosone Christine B. 
Published: May 2015

Background: With over 2.8 million breast cancer survivors in the U.S. today, there is increasing interest and need to identify factors associated with recurrence and survival. The Pathways Study was designed to examine the effects of lifestyle (e.g., diet, physical activity, complementary and alternative medicine [CAM]), psychosocial (e.g., quality of life), molecular and genetic, medical care, and contextual (e.g., social and built environment characteristics) factors on breast cancer prognosis.

Methods: Women newly-diagnosed with invasive breast cancer were identified daily from Kaiser Permanente Northern California (KPNC) electronic pathology records from January 2006 to April 2013; KPNC is a large, integrated health care organization. Eligibility included age at diagnosis of at least 21 y, no previous history of invasive cancer, and English, Spanish or Chinese-speaking. Women were enrolled during an in-person baseline interview that took place on average two months post-diagnosis, with collection of blood and saliva specimens. Active follow-up to update lifestyle and other factors and ascertain outcomes occurs periodically. Outcomes are also identified using KPNC electronic databases and confirmed via medical record review.

Results: The final study cohort consists of 4,505 women, with blood and saliva collected from 90% and 95% of participants, respectively. The cohort has substantial racial/ethnic diversity: 64.2% White, 12.4% Hispanic, 12.8% Asian, 7.9% African American, 2.7% other. The mean age at diagnosis was 59.6 y (range: 23.6-94.8 y). Educational attainment is high, with 84.1% of the cohort having at least some college education. Most women were diagnosed with AJCC Stage I (54.0%) or II (34.6%) cancers, and receptor status was positive for estrogen in 83% of women, progesterone in 63.4%, and Her2 in 12.3%.

As of December 1, 2013, 307 recurrences and 327 deaths have been confirmed, with 490 experiencing either. Initial age-adjusted results with proportional hazards regression demonstrate poorer disease-free survival (DFS) among African Americans (hazard ratio [HR]=1.84, 95% confidence interval [CI],1.39-2.45) and better DFS among Asians (HR=0.70, 95% CI, 0.49, 1.00) compared to Whites. Greater stage at diagnosis, increasing age, and negative ER status are also associated with poorer DFS.

Discussion: The Pathways Study is a rich, unique resource collecting data on multiple factors that may influence breast cancer prognosis, including lifestyle, molecular, medical, and contextual factors. To date, 14 papers have been published on topics ranging from CAM use, quality of life, and physical activity during treatment, to tumor DNA methylation profiles and correlates of breast cancer molecular subtypes. With continued follow-up, it promises to provide findings on factors influencing prognosis to help guide breast cancer care.

Citation Format: Lawrence H. Kushi, Marilyn L. Kwan, Isaac J. Ergas, Cecile A. Laurent, Julie R. Munneke, Janise M. Roh, Heather Greenlee, Chi-Chen Hong, Theresa H. Keegan, Dawn L. Hershman, Susan E. Kutner, Marion M. Lee, Jeanne Mandelblatt, Alfred I. Neugut, Peggy Reynolds, Salma Shariff-Marco, Li Tang, Song Yao, Janice Barlow, Scarlett Lin Gomez, John K. Wiencke, Christine B. Ambrosone. A prospective study of breast cancer prognosis in Kaiser Permanente Northern California: Cohort description and initial findings from the Pathways Study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4127. doi:10.1158/1538-7445.AM2014-4127