There are thousands of chemicals in cigarette smoke, the detrimental effects of which have already been well established. We need only look at a pack of cigarettes for a succinct reminder – in pictorial form – of the myriad of ways smoking can cause harm. It is widely known that smoking is a predominant cause of lung cancer. However, it is less well-known that smoking is an established risk factor for other types of cancer such as colorectal cancer, esophageal cancer, oropharyngeal cancer, bladder cancer, and liver cancer.
The liver is an essential organ in the human body that is responsible for an array of functions such as the biotransformation of drugs, alcohol, and various other substances. Smoking can cause a range of chronic liver diseases such as nonalcoholic fatty liver disease (NAFLD) and hepatocellular carcinoma (HCC). HCC is the most common type of primary liver cancer, and the third leading cause of cancer-related deaths worldwide with an estimated global incidence rate of 9.3 per 100,000 person-years and a nearly equivalent mortality rate of 8.5.
How does tobacco smoking contribute to liver cancer
Tobacco smoke contains several chemicals like 4-aminobiphenyl and polycyclic aromatic hydrocarbons. They are metabolized into carcinogens in the liver and induce histopathological changes like degeneration of liver parenchyma. Tobacco smoke exposure also leads to the release of proinflammatory cytokines, such as IL-33, IL-1β and TNFα and play a crucial role in creating a tumorigenic microenvironment. A major source of 4- aminobiphenyl, a hepatic carcinogen involved as a risk factor for HCC, is cigarette smoking Smoke exposure also induces increased expression of hepatic cancer stem cells and epithelial to mesenchymal transition, which are important determinants of HCC development. Furthermore, there is also an association of smoking with immunosuppression and telomere dysfunction – early events in cancer development. Smoking also acts as a cofactor with Hepatitis C and Hepatitis B and increases the risk of liver fibrosis which is significantly attributed to the development of hepatocellular carcinoma.

What can we do

There are now many resources available to those who want to quit smoking. From pharmacological measures (like Nicotine Replacement Therapy) to community interventions, there is help at hand. Smoking cessation is inversely linked with the risk of hepatocellular carcinoma. Data suggests that individuals who quit smoking 20 years ago have an identical risk to those who have never smoked. In conclusion, smoking cessation has proven a rewarding endeavor for those who undertake it.