MedWire News: A history of smoking is associated with a younger age at breast cancer diagnosis in White, but not Black women, US research shows.
"The mechanisms of possible relationships between smoking and breast cancer are not well understood," write Gary Freedman (Fox Chase Cancer Center, Philadelphia, Pennsylvania) and colleagues.
Freedman and team hypothesized that if tumors of smokers and nonsmokershave different etiology, then they may also have observable differences in clinical presentation and characteristics at diagnosis.
To test this hypothesis, the researchers studied 6000 patients with Tis-T4, N0-N3 breast cancers who presented to a cancer center at initial diagnosis between 1970 and 2006.
The patients were divided into those with any history of tobacco use (45%) and those who had never used tobacco (55%). The researchers then evaluated the association of smoking with clinical, pathologic and treatment-related factors at cancer presentation.
Overall, the median age at breast cancer diagnosis was 55 years. For nonsmokers it was 56 years, and for patients with any smoking history it was 55 years. In a subgroup of patients who were current smokers (n=511), the median age at diagnosis was 52 years. This was significantly younger than the nonsmokers.
Freedman and team found that White patients with a history of smoking were 20% more likely to be younger than 55 years at diagnosis than nonsmokers. Furthermore, current smokers were 67% more likely than nonsmokers to be younger than 55 years at diagnosis. But this association was not observed in Black patients.
There was no statistically significant association between smoking and T stage, N stage, hormone receptor status, or human epidermal growth factor receptor-2 status, but smokers were less likely to utilize breast-conserving treatment than nonsmokers.
Freedman and co-authors conclude in The Breast Journal that "further efforts to clarify potential reasons for any racial differences and lower utilization of breast conservation with smoking are warranted."
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