A common treatment for breast cancer — aromatase inhibitor therapy — is less effective in patients who smoke, according to a new study at Lund University in Sweden.
Aromatase therapy is used to treat postmenopausal women who have estrogen receptor-positive breast cancer. This treatment prevents the body from generating estrogen in fatty tissue and thereby reduces the risk of recurrence.
“Smokers who were treated with aromatase inhibitors had a three times higher risk of recurrence of breast cancer compared with the non-smokers who got the same treatment,” said Dr. Helena Jernström, lead investigator of the study.
“The study also showed that the smokers also had an increased risk of dying, either from the breast cancer or from other illnesses, during the time we followed them.”
For the study, the researchers tracked 1,016 patients in southern Sweden who had been diagnosed with breast cancer between 2002 and 2012. At the time when they were checked in for surgery, they were asked whether they were smokers or non-smokers.
About one in five women reported that she was either a regular smoker or a “social smoker.” The impacts of smoking were analyzed depending on what type of breast cancer treatment the patients received after their surgeries.
The findings show that women over the age of 50 who were treated with aromatase inhibitors had poorer results if they were smokers.
“The treatment with aromatase inhibitors worked significantly better in the non-smoking patients. However, we saw little or no difference between smokers and non-smokers among patients treated with the drug tamoxifen, radiotherapy or chemotherapy. More studies are needed, but our findings are important as many breast cancer patients receive this type of treatment,” Jernström said.
One surprising finding was that so few patients quit smoking during their treatment, despite being informed of the importance of doing so. Out of a total of 206 smokers, only 10 percent quit smoking in the first year after their surgery, a number so small that the researchers could not study whether giving up smoking during treatment had any effect.
“That was unexpected. Smoking is not health-promoting in any way, after all, so it is always beneficial to stop. But these findings show that patients who smoke need more support and encouragement to quit.” said Jernström.
The study is published in the British Journal of Cancer.
Source: Lund University