Lead author Dr. Allen Chen of the University of California, Davis, School of Medicine says although the association between tobacco smoking and head and neck cancers has long been established, there had been little data on whether continued smoking during treatment affects prognosis.
"I've always told patients, 'You should really stop smoking,' but I had no tangible evidence to use to convince them that they would be worse off if they continued to smoke," Chen says in a statement.
"I wanted concrete data to see if smoking was detrimental in terms of curability, overall survival and tolerability of treatment. We showed continued smoking contributed to negative outcomes with regard to all of those."
Chen and colleagues reviewed medical records of 101 patients with newly diagnosed squamous cell carcinoma of the head and neck who continued to smoke during radiation therapy and matched them to similar patients who had quit smoking prior to radiation.
The study, published in the International Journal of Radiation Oncology•Biology•Physics, found 55 percent of patients who had quit smoking prior to treatment were still alive five years later, compared with 23 percent of those who continued to smoke.
Chen and colleagues found 53 of the patients who still smoked experienced disease recurrence compared to 40 patients in the control group.