Another reason to quit smoking after surviving colorectal cancer2 Feb 2015
Colorectal cancer survivors who smoke cigarettes were at more than twice the risk of death than non-smoking survivors, adding to existing evidence associating smoking with higher colorectal cancer-specific and all-cause mortality. The findings come from a new study by American Cancer Society researchers, one of the largest studies of smoking and colorectal cancer survival and the first study to prospectively collect both pre- and post-diagnosis smoking information. It is published early online in the Journal of Clinical Oncology.
Pre- and post-diagnosis smoking information from nearly 2,000 patients
Although there is clear evidence linking smoking with colorectal cancer, its association with survival after colorectal cancer diagnosis is still unclear. To investigate this link, researchers led by Dr. Peter Campbell, identified 2,548 people newly diagnosed with invasive, non-metastatic colorectal cancer from among 184,000 adults in the American Cancer Society's Cancer Prevention Study 2, studying their survival rates during an average of 7.5 years of follow-up time.
The researchers found that those who were smokers before diagnosis, had more than twice the risk of dying of colorectal cancer as well as from all cause as well. However, over the course of the study, smoking after diagnosis was associated with nearly twice the risk of colorectal cancer-specific mortality and with more than double the risk of overall mortality.
Smoking may decrease the efficacy of colorectal cancer treatment
The authors say it is plausible that smokers have pathologically more-aggressive tumors or that smoking may decrease the efficacy of colorectal cancer treatment. "Further research is needed to understand the mechanisms whereby smoking may increase colorectal cancer-specific mortality and determine if quitting smoking after diagnosis lowers the risk of colorectal cancer-specific mortality," the authors conclude.
Source: American Cancer Society