Breast cancer and smoking: It's always a good time to stop

In the last 20 years, the incidence of breast cancer has increased but the outlook for women diagnosed with it has also improved considerably. Figures from the United States show that 4 per cent of the population are now cancer survivors and 41 per cent of female cancer survivors have had breast cancer.

Nowadays, many women with breast cancer, especially those diagnosed later in life, are likely to die of another cause, such as a heart attack or stroke, rather than their breast cancer. It’s worth noting that smoking is an important risk factor for both heart attack and stroke.

Over the last 6 years, we’ve been doing a study of over 1600 Victorian women diagnosed with their first episode of invasive breast cancer. The research has concentrated on the psychosocial consequences for women of diagnosis and treatment. The women who took part in the study were recruited though the Victorian Cancer Registry and we know they are representative of women diagnosed with breast cancer in Victoria.

What we found was that these women frequently choose to make lifestyle changes after diagnosis. The most common changes we observed were dietary and increases in physical activity – both reported by about one third of women.

Although there’s a health benefit in increasing physical activity for most women, the benefits for some of the reported dietary changes were unclear. We wondered about changes to lifestyle where there could be no argument about the benefit – such as stopping smoking.

We found that 12 per cent of women were smokers at the time of diagnosis and only about a third of these had quit two years later. Of the women who continued to smoke, one in four was smoking fewer cigarettes per day than they were at the time of diagnosis.

When trying to understand the factors that contributed to women’s smoking, we found that compared with women who had quit by two years after diagnosis, women who continued to smoke were heavier smokers at the time of diagnosis. A small number of women who described themselves as ex-smokers at diagnosis actually reported resuming smoking in the following two years.

Smoking is a risk factor for breast cancer and women with a history of the disease are already at risk of recurrence as well as the development of a new primary breast cancer.

There are other problems with smoking too. Radiotherapy is frequently used in the treatment of breast cancer. Although it’s clearly useful in reducing the risk of breast cancer recurrence, radiotherapy increases the risk of lung cancer and this risk is amplified in smokers.

Another argument for quitting smoking is to minimise risks associated with the initial surgical management of the cancer and any follow-up surgical procedures, such as reconstructive surgery. Smokers are at much greater risk than non-smokers for a range of complications following surgery, including blood clots, chest infections and poor wound healing.

All these are good reasons for women with breast cancer to quit smoking. But there’s another good reason apart from them: given that the prognosis for women with the disease is now so good, women diagnosed with breast cancer should quit smoking for the same reasons that all women are advised to quit – to reduce their risk of heart attack, stroke and respiratory disease.

Provided by Monash University