Clearing the Air: Does Smoking Increase Breast Cancer Risk? – Komen Perspectives

Jul 01, 2020 | Komen Perspectives

Say the word “smoking,” and the word “cancer” is never far behind – and rightfully so. Smoking causes over 11 different types of cancer (including lung, kidney, colon and esophageal cancer) and is also a major contributor to heart disease, stroke, diabetes, emphysema and bronchitis. Smoking kills over 440,000 people each year in the United States, and, on average a smoker will die 14 years earlier than someone who doesn’t smoke.1

Does smoking increase breast cancer risk?

Given smoking’s link with so many serious diseases, it may be surprising to hear that when it comes to breast cancer, smoking isn’t strongly related to risk. While some studies have found that smoking can increase risk – especially in long-term smokers and those who start smoking at a younger age – others have found no effect.2-5 More studies are needed before any solid conclusions can be made about the exact link between smoking and breast cancer.

For a summary of research studies on smoking and breast cancer, visit the Breast Cancer Research section.

What about secondhand smoke and breast cancer risk?

Findings from studies on secondhand smoking (breathing in smoke from other people’s cigarettes) are mixed as well. Some studies have shown breathing secondhand smoke increases breast cancer risk, while others have not.5-6

For a summary of research studies on secondhand smoke and breast cancer, visit the Breast Cancer Research section.

What is it about smoking that could affect breast cancer risk?

To start with, tobacco smoke contains at least 250 harmful chemicals and over 65 of these are known carcinogens.7 In addition, smokers can have certain behaviors that could also increase the risk of breast cancer. Compared to non-smokers, smokers tend to have fewer children and to drink more alcohol, both of which can increase breast cancer risk.8 On the other hand, smokers can also have some characteristics that can actually lower risk. On average, they weigh less than non-smokers and also tend to go through menopause earlier.9 Both of these lower lifetime exposure to the hormone estrogen, which can lower the risk of breast cancer.

This mixed effect of smoking could be one reason the link between smoking and breast cancer remains unclear.

What does this mean for me?

With smoking already at the top of nearly every single “do not” list when it comes to health, the ongoing discussions about a link between smoking and breast cancer makes little difference in the real world. Whether it slightly increases breast cancer risk or not, smoking has such a broad negative impact on health that no one should smoke no matter what its effect on breast cancer. According to Dr. Graham Colditz, Associate Director of the Alvin J. Siteman Cancer Center and Niess-Gain Professor in the School of Medicine at Washington University School of Medicine, “While the evidence on smoking and risk of breast cancer remains mixed, the shorter life of smokers compared to non-smokers, as well as the increase in cancer, heart disease and stroke, all warrant stopping smoking for those who currently smoke and avoiding starting for anyone who does not smoke.”

Anyone who smokes should quit as soon as possible. It’s never too late to benefit from quitting. The risk of heart disease goes down very quickly after stopping smoking and over time the risk of lung and other cancers can drop to near that of someone who never smoked.7 Talking to a health care provider can double the chances of success in quitting.10  

Maintaining a smoke-free home is one of the best things people can do to look after their own health and the health of their family and friends.10  

What help is there for smokers who want to quit? 
There are a lot of great resources for smokers who want to quit. Many local hospitals, medical centers and pubic health offices offer cessation classes and other help. State and national organizations also offer a wide range of free services and can help smokers develop personalized quit plans, locate health care providers and connect with others who are trying to quit. Some state and national level resources include:American Cancer Society – Guide to Quitting Smoking Lung Association – Freedom from Smoking  National Cancer Institute’s Free Help to Quit Smoking 
1-877-44U-QUIT (1-877-448-7848)National Cancer Institute’s 
www.women.smokefree.govState Tobacco Quit Lines 
1-800-QuitNow (1-800-784-8669)U.S. Department of Defense – Quit Tobacco


  1. Centers for Disease Control and Prevention. Tobacco-related mortality., 2011.
  2. Hamajima N, Hirose K, Tajima K, et al. Alcohol, tobacco and breast cancer–collaborative reanalysis of individual data from 53 epidemiological studies, including 58,515 women with breast cancer and 95,067 women without the disease. Br J Cancer. 87(11):1234-45. 2002. 
  3. Lawlor DA, Ebrahim S, Smith GD. Smoking before the birth of a first child is not associated with increased risk of breast cancer: findings from the British Women’s Heart and Health Cohort Study and a meta-analysis. Br J Cancer. 91:512-8, 2004.
  4. DeRoo LA, Cummings P, Mueller BA. Smoking before the first pregnancy and the risk of breast cancer: a meta-analysis. Am J Epidemiol. 174(4):390-402, 2011. 
  5. Institute of Medicine. Breast Cancer and the Environment: A Life Course Approach: The National Academies Press, 2012.
  6. Pirie K, Beral V, Peto R, Roddam A, Reeves G, Green J. Passive smoking and breast cancer in never smokers: prospective study and meta-analysis. Int J Epidemiol. 37(5):1069-79, 2008.
  7. National Cancer Institute. Harms of smoking and health benefits of quitting., 2011.
  8. Cui Y, Miller AB, Rohan TE. Cigarette smoking and breast cancer risk: update of a prospective cohort study. Breast Cancer Res Treat. 100(3):293-9, 2006.
  9. Gram IT, Braaten T, Terry PD, et al. Breast cancer risk among women who start smoking as teenagers. Cancer Epidemiol Biomarkers Prev. 14:61-6, 2005.
  10. Centers for Disease Control and Prevention. Five keys for quitting smoking., 2011.