Women who smoke or who have smoked face a 39 percent higher risk of death due to breast cancer, claims a new study.
Although smoking is associated with lung cancer and implicated in several other cancers, it is unclear what effect smoking has on breast cancer, said Dejana Braithwaite of the University of California.
"Specifically, it is unclear how long women live following breast cancer diagnosis and whether smoking increases the risk of death because of breast cancer progression or whether there is an association between smoking and life expectancy following breast cancer diagnosis that works through affecting non-breast cancer causes of death," she said.
Braithwaite and colleagues enrolled 2,265 multi-ethnic women diagnosed with breast cancer between 1997 and 2000. Researchers examined whether smoking affected death from breast cancer, non-breast cancer related causes and death from all causes.
Results showed that 164 deaths from breast cancer and 120 deaths from non-breast cancer causes occurred during follow-up.
Women who were current or past smokers and also had a HER2-negative tumour subtype had a 61 percent increased risk for breast cancer death compared with those who never smoked.
"The implication of this research is that it is important for physicians to improve smoking cessation efforts, especially among women newly diagnosed with breast cancer, in order to improve breast cancer specific outcomes and overall health outcomes," said Braithwaite.
The findings were presented at the Ninth Annual AACR Frontiers in Cancer Prevention Research Conference.