Breast cancer occurs when abnormal breast cells grow out of control and form tumors, which can spread to other parts of the body (metastasize), with potentially fatal outcomes. Breast cancer is a significant health concern, causing 670,000 deaths globally and representing the most common cancer in women in 85 percent of countries in 2022. While smoking has traditionally been associated with lung cancer, it is now increasingly linked to breast cancer.
In this article, we will explore the link between smoking and breast cancer and the benefits that quitting can have not only on your overall health and well-being but also on your cancer risk.
Several studies have investigated the link between smoking and breast cancer, indicating an increased risk of breast cancer with smoking. One study showed a 16 percent increased risk of breast cancer among current smokers and a nine percent increased risk among former smokers, compared to women who have never smoked.
Smoking is also linked to a higher risk of postmenopausal breast cancer, particularly in women with high levels of estrogen. Smoking was associated with a higher risk in women with elevated levels of estrone and estradiol (forms of estrogen).
The risk of smoking increases further with smoking duration and intensity. For example, a study showed that women who smoked more than 20 pack-years had a 27 percent increased risk, while those who smoked more than 15 grams per day had a 31 percent increased risk. The duration of smoking also increases the risk of cancer development, with one study showing a significantly increased risk after 30 years of smoking and another showing an increase in risk of 30-40 percent after 40 years.
It is not only active smokers who are at increased risk of breast cancer; there is robust evidence showing a higher risk among passive smokers. Studies have shown a risk 1.67 times to three times higher in non-smokers who had been exposed to passive smoking compared to those who had never been exposed.
As with active smoking, increased duration and intensity of passive smoking results in an increase in risk. One study reported a significantly higher risk in women exposed to passive smoking for most of their lives, while another reported a 32 percent increase in risk in postmenopausal women with extensive passive smoking exposure compared to those who had never been exposed.
Toxins in cigarette smoke, such as polycyclic aromatic hydrocarbons (PAHs), nitrosamines, and aromatic amines, cause DNA damage in breast cells by forming DNA adducts. These adducts are segments of DNA that become chemically bonded to a cancer-causing substance and can evade DNA repair mechanisms, leading to permanent mutations.
Moreover, smoking increases the incidence of mutations in p53, a gene that helps regulate cell division and death and plays a role in preventing cancer. These mutations hinder the body’s ability to respond to oncogenic signals, leading to tumor formation.
Aside from increasing the risk of developing breast cancer, smoking also worsens outcomes for patients undergoing treatment. Not only do active smokers have a higher chance of breast cancer-related mortality than non-smokers, but continuing to smoke after diagnosis increases the risk of mortality even further.
This is because smoking can affect the response to treatments, including endocrine therapies such as tamoxifen and aromatase inhibitors. This means that smokers with hormone receptor-positive breast cancer have a higher likelihood of disease progression and new metastases during endocrine therapy compared to non-smokers. Additionally, continuing to smoke increases the chance of cancer recurrence.
Evidently, stopping smoking is important for risk reduction, and the good news is that multiple studies have shown a significant decrease in breast cancer risk after quitting smoking. Former smokers have a lower risk of developing breast cancer the longer it's been since they quit smoking. While the risk remains higher than non-smokers for up to 20 years after quitting, it gradually decreases as more time passes without smoking.
In terms of prognosis, women who quit smoking after a breast cancer diagnosis have lower mortality rates compared to those who continue smoking, with former smokers showing a significantly better 10-year overall survival rate compared to current smokers.
In addition to reducing the risk of breast cancer development and associated mortality, quitting smoking has numerous other positive effects on overall health. These include:
There are many resources available to help those trying to quit smoking:
Genetic predisposition is another major risk factor for breast cancer, and smoking can compound risks in genetically predisposed people. In families with a high genetic risk of breast cancer, smoking increases the risk significantly. Women from high-risk families who smoked had a 2.4-fold increased risk, and this was even higher in families with the strongest genetic predisposition. Specifically, women with mutations in BRCA1 or BRCA2 genes who smoke are at an increased risk of developing breast cancer.
In addition to smoking and genetic predisposition, certain lifestyle factors can also increase the risk of breast cancer. Notably, the cumulative risk associated with smoking is even greater when combined with these factors.
Early detection of breast cancer is crucial for improving treatment outcomes, especially for individuals with a history of smoking, as they may have a higher risk of developing the disease. Regular screenings like mammograms and MRIs can catch breast cancer in its early stages when it's most treatable.
Ezra’s screenings offer a valuable tool in detecting breast cancer early, even before symptoms appear. By identifying cancer at an earlier, more manageable stage, these screenings can significantly improve survival rates and treatment success.
The link between smoking and breast cancer is becoming increasingly evident, with both active and passive smoking contributing to heightened risk. Smoking not only raises the likelihood of developing breast cancer but also worsens treatment outcomes. However, quitting can significantly reduce the risk of breast cancer and improve overall health.
Consider taking proactive steps in your health journey by booking an Ezra scan which can screen for early signs of breast cancer and other cancers. Early detection can save lives. Book your scan today.
