Smoking History in Relation to Survival after a Breast Cancer Diagnosis
Authors: Newcomb PA , Passarelli MN , Hampton JM , Trentham-Dietz A , Egan KM , Titus LJ 
Published: March 2014

Abstract
Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.Smoking history is associated with increased risk of most cancers, including breast cancer. Given the persistent effects of tobacco carcinogens, smoking history may also influence breast cancer survival. The few previous studies assessing this association were hindered by limited numbers of outcomes. METHODS: We assessed pre-diagnosis tobacco smoking in relation to survival in 22,870 female residents of Wisconsin, Massachusetts, or New Hampshire who were diagnosed with incident, invasive breast cancer between 1988–2008 at ages 20–79. All women reported pre-diagnosis tobacco use, as well as other known and suspected breast cancer risk factors. Information on breast cancer staging was obtained from state cancer registries. Proportional hazards regression with baseline hazard stratified on state of residence and study phase was used to estimate adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cause-specific death according to current smoking (at the time of the breast cancer diagnosis) and long-term (&gt;30 years) smoking (prior to the diagnosis) adjusting for age at diagnosis, stage of disease at diagnosis, family history of breast cancer, age at first birth, menopausal status, hormone therapy use, body mass index, alcohol consumption, education, and mammography. RESULTS: During a median follow-up of 11.3 years from diagnosis, 7,807 deaths occurred, including 3,483 attributed to breast cancer, 328 to lung cancer, 415 to respiratory disease, and 1,553 to cardiovascular disease. Compared to nonsmokers, the HR were 1.2 (1.1–1.3. P = trend = 0.0003) for current smokers and 1.2 (1.1–1.3, P trend = 0.01) for &gt;30 years of smoking. Current smoking was also associated with increased mortality from lung cancer, HR = 14.5 (10.1–20.8), cardiovascular disease, HR = 2.2 (1.9–2.5), and respiratory disease HR = 6.3 (4.8–8.2). CONCLUSIONS: In this large population-based sample of breast cancer cases, current and long-term smokers at the time of diagnosis were 20% more likely to die from breast cancer than never smokers adjusting for breast cancer stage. The elevated mortality risk observed here for known smoking-related diseases adds confidence to the breast cancer findings.