Smoking history contributes to poor outcomes in the treatment of lung cancer, according to a new study. Non-small-cell lung cancer (NSCLC) patients who have never smoked before have better overall survival rates and respond better to chemotherapy than current or former smokers. Published in the June 1, 2006, issue of CANCER, the study also reveals that smoking status during treatment has no effect on clinical outcome.
Cigarette smoking is the most significant risk factor for developing lung cancer. The 5-year survival rate for patients diagnosed with lung cancer is less than 20% at best. NSCLC causes the majority of lung cancers, and if cured, the survivor has up to a 4% annual risk of developing another tumor.
Despite the association of lung cancer with cigarettes, diagnosed patients continue to smoke. However, physicians remain unable to tell their patients how that will affect their cancer treatment. Previous studies have failed to agree on whether smoking status impacts the outcome of chemotherapy or chemotherapy plus thoracic irradiation.
Led by Anne S. Tsao, MD, of the University of Texas M. D. Anderson Cancer Center in Houston, researchers reviewed the medical records of 1,370 patients with NSCLC who were treated with chemotherapy or chemoradiation to determine associations between smoking, treatment response, and survival.
The researchers found that patients who never smoked had a better response to the chemotherapy, developed less disease progression during therapy, and showed improved survival over former and current smokers. They say the finding may be due to nonsmokers having less genetic damage compared to smokers, being less likely to have other ailments that would affect survival, and having better-preserved lung function.
The authors write that "Continued efforts at preventing smoking initiation are a critical public health issue and emphasize the need for chemoprevention for smokers and primary-prevention protocols to prevent smoking."