Breast Cancer Risk Factors and Survival by Tumor Subtype: Pooled Analyses from the Breast Cancer Association Consortium.
Morra A., Jung AY., Behrens S., Keeman R., Ahearn TU., Anton-Culver H., Arndt V., Augustinsson A., Auvinen PK., Beane Freeman LE., Becher H., Beckmann MW., Blomqvist C., Bojesen SE., Bolla MK., Brenner H., Briceno I., Brucker SY., Camp NJ., Campa D., Canzian F., Castelao JE., Chanock SJ., Choi J-Y., Clarke CL., Couch FJ., Cox A., Cross SS., Czene K., Dörk T., Dunning AM., Dwek M., Easton DF., Eccles DM., Egan KM., Evans DG., Fasching PA., Flyger H., Gago-Dominguez M., Gapstur SM., García-Sáenz JA., Gaudet MM., Giles GG., Grip M., Guénel P., Haiman CA., Håkansson N., Hall P., Hamann U., Han SN., Hart SN., Hartman M., Heyworth JS., Hoppe R., Hopper JL., Hunter DJ., Ito H., Jager A., Jakimovska M., Jakubowska A., Janni W., Kaaks R., Kang D., Kapoor PM., Kitahara CM., Koutros S., Kraft P., Kristensen VN., Lacey JV., Lambrechts D., Le Marchand L., Li J., Lindblom A., Lubiński J., Lush M., Mannermaa A., Manoochehri M., Margolin S., Mariapun S., Matsuo K., Mavroudis D., Milne RL., Muranen TA., Newman WG., Noh D-Y., Nordestgaard BG., Obi N., Olshan AF., Olsson H., Park-Simon T-W., Petridis C., Pharoah PDP., Plaseska-Karanfilska D., Presneau N., Rashid MU., Rennert G., Rennert HS., Rhenius V., Romero A., Saloustros E., Sawyer EJ., Schneeweiss A., Schwentner L., Scott C., Shah M., Shen C-Y., Shu X-O., Southey MC., Stram DO., Tamimi RM., Tapper W., Tollenaar RAEM., Tomlinson I., Torres D., Troester MA., Truong T., Vachon CM., Wang Q., Wang SS., Williams JA., Winqvist R., Wolk A., Wu AH., Yoo K-Y., Yu J-C., Zheng W., Ziogas A., Yang XR., Eliassen AH., Holmes MD., García-Closas M., Teo SH., Schmidt MK., Chang-Claude J., ABCTB Investigators None., NBCS Collaborators None.
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: There was no evidence of heterogeneous associations between risk factors and mortality by subtype (P adj > 0.30). The strongest associations were between all-cause mortality and BMI ≥30 versus 18.5-25 kg/m2 [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.