The Role of Smoking in the Development of Colorectal Cancer

Introduction. Smoking is an important public health issue nowadays. It causes a lot of diseases and represents also a source of carcinogenic substances. Recent studies showed an increased incidence of colorectal cancer in smokers. The aim of our study is to assess the association between smoking and colorectal cancer and to establish the prevalence of heavy smokers among the patients operated on for colorectal cancer.
Methodology. We run a retrospective study of the charts belonging to the patients diagnosed with colorectal cancer and operated on in our department between 2004 and 2013. The patients were classified in smokers, former smokers and nonsmokers. The amount of tobacco was evaluated according to the number of smoked cigarettes per day, the smoking period, respectively the pack-years. The data were corroborated with the location of the tumor and analyzed using the online version of Graphpad.
Results. From 982 patients diagnosed with colorectal cancer, we found 297 smokers (30.24%). Among these, 106 patients (35.69%) have smoked for over 30 years, at least 20 cigarettes per day, more than 30 pack-years. The number of heavy smokers was significantly greater (p=0.0001) in the group with rectal cancer compared to the group with colon cancer. The association of smoking with rectal cancer was also important (p=0.0015) among the former smokers.
Conclusions. Smoking is related to higher incidence of colorectal cancer. Our data sustain the hypothesis of increased risk of developing rectal cancer in heavy smokers. We recommend the screening for colorectal cancer among the heavy smoker population.