New Study Finds Smokers Less Likely to Survive Colon Cancer

Current smokers living with colorectal cancer are more likely to die from the disease than non-smokers or people who have quit smoking, researchers say.

This finding is based on the examination of the five-year survival odds of 18,166 patients diagnosed with colorectal cancers in Ireland between 1994 and 2012. Current smokers among that group were 14 percent more likely to die within the five-year study period than non-smokers. Smokers who underwent surgery but did not have chemotherapy had an even greater risk being 21 percent more likely to die.

In a recent article for Reuters Health, Dr. David Weinberg of the Fox Chase Cancer Center in Philadelphia said doctors are not sure why the increased risk exists.  

“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,” Weinberg said. “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.”

More than half of the patients followed in the study had treated their cancer with surgery only. A third had chemotherapy and surgery. A small group of 5 percent had only chemotherapy and 10 percent had none of these treatments.

The majority of patients in the study were 55 years or older. Only 13 percent were younger while 35 percent were 75 or older. Twenty percent were current smokers and 23 percent had quit smoking.

Within the five-year study period, 7,488 people died of cancer. Researchers found that even after adjusting for factors like age, marital status, and cancer characteristics, those patients who were current smokers had a statistically meaningful increased risk of death. Former smokers did not have the same risk.

“This study clearly shows that immediate and long-term survival is affected by smoking, more by continued smoking but also by prior smokers,” said Dr. Sidney Winawer of Memorial Sloan Kettering Cancer Center in New York.

The study is the largest of its kind to show a link between smoking and colorectal cancer.

To learn more, you can read the study abstract.