With colon cancer, smokers less likely to survive

Current smokers diagnosed with colorectal cancer are more likely to die from it than former smokers or people who never tried cigarettes, a recent study suggests.

Researchers examined five-year survival odds for 18,166 people diagnosed with colorectal cancer and found current smokers were 14 percent more likely to die during the study period than people who never smoked. The effect was seen mainly among smokers treated with surgery but no chemotherapy, who were 21 percent more likely to die.

“We don’t know exactly how smoking causes colorectal cancer in this case or makes prognosis worse; however it clearly does just like in many other human cancers,” said Dr. David Weinberg of the Fox Chase Cancer Center in Philadelphia.

“Not smoking, maintaining a healthy body weight, exercising regularly and drinking in moderation have been shown to consistently reduce risk for many common cancers including lung and colorectal cancers,” Weinberg, who wasn’t involved in the study, added by email.

Worldwide each year, about 750,000 new cases of colorectal cancers are diagnosed, with about two-thirds developing in the colon.

For the current study, researchers examined cancer registry data for patients diagnosed with colorectal cancers in Ireland from 1994 to 2012.

Most patients were at least 55 years old at the time of diagnosis, though 13 percent were younger. About 35 percent of patients were at least 75 years old.

Overall, 3,572 patients, or 20 percent, were current smokers, and another 4,199, or 23 percent, were former smokers.

About 53 percent of them had only surgery, while 33 percent had chemotherapy in addition to operations and 5 percent had only chemotherapy. Roughly 10 percent of patients had none of these interventions.

During five years of follow-up, 7,488 people died of cancer, researchers report in Alimentary Pharmacology and Therapeutics. –