Breast Cancer Risk Factors and Survival by Tumor Subtype: Pooled Analyses from the Breast Cancer Association Consortium
Anna Morra, Audrey Jung, Sabine Behrens, Renske Keeman, Thomas U. Ahearn, Hoda Anton‐Culver, Volker Arndt, Annelie Augustinsson, Päivi Auvinen, Laura E. Beane Freeman, Heiko Becher, Matthias W. Beckmann, Carl Blomqvist, Stig E. Bojesen, Manjeet K. Bolla, Hermann Brenner, Ignacio Briceño, Sara Y. Brucker, Nicola J. Camp, Daniele Campa, Federico Canzian, Jose E. Castelao, Stephen J. Chanock, Ji‐Yeob Choi, Christine L. Clarke, Fergus J. Couch, Angela Cox, Simon S. Cross, Kamila Czene, Thilo Dörk, Alison M. Dunning, Miriam Dwek, Douglas F. Easton, Diana M. Eccles, Kathleen M. Egan, D. Gareth Evans, Peter A. Fasching, Henrik Flyger, Manuela Gago-Domínguez, Susan M. Gapstur, José Á. García-Sáenz, Mia M. Gaudet, Graham G. Giles, Mervi Grip, Pascal Guénel, Christopher A. Haiman, Niclas Håkansson, Per Hall, Ute Hamann, Sileny Han, Steven N. Hart, Mikael Hartman, Jane Heyworth, Reiner Hoppe, John L. Hopper, David J. Hunter, Hidemi Ito, Agnes Jager, Milena Jakimovska, Anna Jakubowska, Wolfgang Janni, Rudolf Kaaks, Daehee Kang, Pooja Middha, Cari M. Kitahara, Stella Koutros, Peter Kraft, Vessela N. Kristensen, James V. Lacey, Diether Lambrechts, Loı̈c Le Marchand, Jingmei Li, Annika Lindblom, Jan Lubiński, Michael Lush, Arto Mannermaa, Mehdi Manoochehri, Sara Margolin, Shivaani Mariapun, Keitaro Matsuo, Dimitrios Mavroudis, Roger L. Milne, Taru Muranen, William G. Newman, Dong‐Young Noh, Børge G. Nordestgaard, Nadia Obi, Andrew F. Olshan, Håkan Olsson, Tjoung‐Won Park‐Simon, Christos Petridis, Paul D.P. Pharoah, Dijana Plaseska‐Karanfilska, Nadège Presneau, Muhammad Usman Rashid, Gad Rennert, Hedy S. Rennert, Valerie Rhenius, Atocha Romero, Emmanouil Saloustros
Abstract
BACKGROUND: It is not known whether modifiable lifestyle factors that predict survival after invasive breast cancer differ by subtype. METHODS: We analyzed data for 121,435 women diagnosed with breast cancer from 67 studies in the Breast Cancer Association Consortium with 16,890 deaths (8,554 breast cancer specific) over 10 years. Cox regression was used to estimate associations between risk factors and 10-year all-cause mortality and breast cancer-specific mortality overall, by estrogen receptor (ER) status, and by intrinsic-like subtype. RESULTS: [HR (95% confidence interval (CI), 1.19 (1.06-1.34)]; current versus never smoking [1.37 (1.27-1.47)], high versus low physical activity [0.43 (0.21-0.86)], age ≥30 years versus <20 years at first pregnancy [0.79 (0.72-0.86)]; >0-<5 years versus ≥10 years since last full-term birth [1.31 (1.11-1.55)]; ever versus never use of oral contraceptives [0.91 (0.87-0.96)]; ever versus never use of menopausal hormone therapy, including current estrogen-progestin therapy [0.61 (0.54-0.69)]. Similar associations with breast cancer mortality were weaker; for example, 1.11 (1.02-1.21) for current versus never smoking. CONCLUSIONS: We confirm associations between modifiable lifestyle factors and 10-year all-cause mortality. There was no strong evidence that associations differed by ER status or intrinsic-like subtype. IMPACT: Given the large dataset and lack of evidence that associations between modifiable risk factors and 10-year mortality differed by subtype, these associations could be cautiously used in prognostication models to inform patient-centered care.