People with the most fatal type of skin cancer who have a history of smoking are 40 percent less likely to survive their disease than people who have never smoked, according to a new study from the UK.
There are around 180,000 cases of melanoma in the U.S. per year and although it has a good chance of survival if detected early, it still kills over 9,000 Americans annually.
The study published today in the journal Cancer Research and funded by Cancer Research UK looked at more than 700 patients with melanoma and found that smokers were 40 per cent less likely to survive the disease than people who have never smoked.
“It has been reported that smoking can have an effect on immunity and can have direct effects on cancer cells,” said Julia Newton-Bishop, Professor of dermatology at the University of Leeds and lead author of the study.
The scientists looked at the patterns of genes expressed in the tumors and in a subset of 156 patients who had the strongest genetic signal for immune cells within the tumor, smokers were around four and a half times less likely to survive from the cancer than people who had never smoked.
The genetic signals indicated that the number of the immune cells in the tumors was similar in smokers and non-smokers but in smokers the presence of immune cells didn’t give the same survival benefit.
“The immune system is like an orchestra, with multiple pieces. This research suggests that smoking might disrupt how it works together in tune, allowing the musicians to continue playing but possibly in a more disorganized way,” said Newton-Bishop.
The immune cells seem to have entered the tumors to attempt to tackle them as expected, but the patients don’t appear to benefit from this, leading the researchers to suspect that smoking might be affecting their function.
“The result is that smokers could still mount an immune response to try and destroy the melanoma, but it appears to have been less effective than in never-smokers, and smokers were less likely to survive their cancer,” said Newton-Bishop.
Smoking has been reported to have an adverse effect on the immune system, but it isn’t exactly known which chemicals in tobacco currently cause this. Although the scientists strongly suspect that smoking is responsible for these adverse effects on the immune system and hence reduced survival from melanoma, they can’t currently prove this for certain.
“This study asked all participants about a number of different exposures and smoking was found to be strongly associated with survival. While we can’t exclude the possibility that the effect seen with smoking is actually attributable to a different behavior, that behavior would have to be very strongly related to smoking,” said Newton-Bishop.
The new findings provide yet another reason to add to the seemingly endless list of health concerns as to why people should give up smoking, particularly those who have been diagnosed with malignant melanoma, but is there any difference between people with melanoma who used to smoke and those who currently do?
“Our data could not differentiate with confidence between the effect of past smoking and current smoking; to distinguish would require a much larger study, with smokers who quit at different times before their melanoma diagnosis. Based on these findings, stopping smoking should be strongly recommended for people diagnosed with melanoma,” said Newton-Bishop.