The health risks associated with smoking are well known, and so it’s not surprising that smoking after a CML diagnosis adds to the burden of illness in a somewhat indirect way. However, the most recent study suggests that smoking may have harmful effects on the biology underlying CML (Lauseker and colleagues. Cancer 2017; epublished February 13, 2017).
An analysis was performed on data from the German CML Study IV, a trial launched a decade ago that compared various Gleevec regimens (Berger and colleagues. Ann Hematol 2004;83:258-264). The likelihood of surviving 8 years was 87% for nonsmokers compared to 83% for smokers. The risk of death was estimated to be about two-fold higher in smokers.
A further finding was that the estimated risk of CML worsening was also two-fold higher/ This suggested that smoking was having a direct effect on the disease mechanisms that drive progression, although smoking did not appear to affect an individual’s response to medication.
Whether there is a direct connection between CML and smoking is somewhat controversial. A recent meta-analysis of 10 studies found that smokers were not more likely than non-smokers to develop CML (Qin and colleagues. Hematology 2016;2:1-8). However, that may change with the dose and/or duration of smoking. The researchers found that the estimated risk of developing CML was 24% higher in people who smoked more than 20 cigarettes a day, and 40% higher in people with a 30 pack-year history of smoking.