A substantial number of lung and colorectal cancer patients continue to smoke after being diagnosed, a new study has revealed. When a patient receives a cancer diagnosis, the main focus is to treat the disease. But stopping smoking after a cancer diagnosis is also important because
continuing to smoke can negatively affect patients responses to treatments, their subsequent cancer risk, and, potentially, their survival.

A team led by Elyse R. Park, PhD, MPH, of the Massachusetts General Hospital/Harvard Medical School in Boston, studied how many patients quit smoking around the time of a cancer diagnosis, and which smokers were most likely to quit.

The investigators determined smoking rates around the time of diagnosis and five months after diagnosis in 5,338 lung and colorectal cancer patients.

At diagnosis, 39 percent of lung cancer patients and 14 percent of colorectal cancer patients were smoking, five months later, 14 percent of lung cancer patients and 9 percent of colorectal cancer patients were still smoking.

These results indicate that a substantial minority of cancer patients continue to smoke after being diagnosed. Also, although lung cancer patients have higher rates of smoking at diagnosis and following diagnosis, colorectal cancer patients are less likely to quit smoking following diagnosis.

Factors and characteristics that predicted continued smoking differed by cancer type. Lung cancer patients who continued smoking tended to have Medicare or other public health insurance, have a lower body mass index, have low emotional support, not have received chemotherapy, not have had surgery, have had prior heart disease, and have smoked a high number of cigarettes per day at some point during their lives.

Colorectal cancer patients who continued to smoke tended to be male, have completed less education, be uninsured, not have had surgery, and have once smoked a high number of cigarettes per day.

"These findings can help cancer clinicians identify patients who are at risk for smoking and guide tobacco counseling treatment development for cancer patients," said Dr. Park.