Smoking Responsible for Many Deaths from Cancers

According to a new report published in the peer reviewed Journal of American Medical Association (Internal Medicine), investigators suggested that more than 50% of all cancer related deaths are attributed to active smoking. For example, based on several studies, it has been observed that chronic active smoking plays a significant role in the pathogenesis of malignant lesions of esophagus, bladder, colon, rectum, nose and sinuses, stomach, kidney, cervix, lungs, uterus, ovary, mouth/ oral cavity, lips, larynx, pharynx, acute myeloid leukemia and pancreas. Besides contributing to the pathophysiology of cancer; a positive history of smoking is also associated with worse prognosis, high morbidity and even higher mortality rate in cancer sufferers.

Relationship between Smoking and High Mortality

Investigators analyzed the 2011 statistical data of 12 most common cancers that are linked to smoking and identified that mortality rate was much higher in smokers. Based on the latest data:

• The mortality rate in smokers suffering from lung, trachea and bronchus malignancy is over 80%. This corresponds to 45% of all cancer-related mortalities or 126,000 cancer deaths in 2011 alone).
• More than 76% of all deaths in the setting of laryngeal malignancy are attributed to tobacco use.
• More than 50% cancer-related deaths in patients of bladder malignancy or tumors of oral cavity is also linked to active smoking.
• Female smokers are 25-times more likely than non-smoker females to develop the malignancy of lungs.

Although, a significant decline has been reported in the smoking trend over the past few decades; yet it is still classified as the number one reported cause of lung cancer in the United States.

Pathophysiology of smoking and carcinogenesis

Extensive medical research and several clinical studies have helped a great deal in explaining how smoking leads to cancer formation in the living tissues. Here are some explanations:

• Cigarette smoke contains at least 60 known carcinogens and more than 200 toxic chemicals that are known to directly cause mutations in the rapidly growing cells (such a lining cells or epithelial cells).
• Cigarette smoke and other gases that are inhaled during smoking process can elicit a strong inflammatory response in the living tissues. With repeated and recurrent exposure to cigarette smoke, the chronic inflammatory damage can further aggravates the risk of permanent damage to biological tissues; thereby increasing the risk of carcinogenesis.
• Chronic smoking also alters the natural biochemical environment of the body by interfering with normal secretory processes (such as hormones), which may compromise the physiological immune functioning of the body.
• Smokeless tobacco products are loaded with chemicals like nitrosamines (a known carcinogen) that is associated with malignant lesions of oral cavity and other parts of digestive system (pancreas, esophagus and pharynx).

According to a global study that was conducted during 2008 -2010, it was reported that the prevalence of smoking is 48·6% in males and as high as 11.3% in females (3). This corresponds to more than 42 million Americans who consume more than 30 smokes/ cigarettes per day. Unfortunately, the figures in females are on the rise. It is imperative to mention that tobacco smoking is also responsible for other life threatening diseases and disorders; such as hypertension, chronic obstructive pulmonary disease, cardiovascular ailments, atherosclerosis etc. In fact, according to US Surgeon General Report of 2014, more than 20% of all deaths (or 1 in every 5 deaths) are attributed to tobacco use in United States (2). Likewise, the economic cost of cigarette smoking is also huge. Based on latest estimates, the direct and indirect healthcare economic cost of tobacco use in United States is approximately $289 and $332.5 billion.

It is highly recommended to educate masses regarding the hazardous effects and consequences of chronic smoking. It is also very important to introduce alternatives/ substitutes to active smokers to help quit tobacco use. For example, according to a study reported in the American Journal of Public Health (4), investigators suggested that e-cigarettes are regarded as the most popular alternative tobacco product among other options like dissolvables, moist snuff, loose leaf and snus. The report also highlighted that individuals are more likely to quit cigarette smoking if they get their hands on a reliable tobacco alternative product. Interventions are also needed because secondhand or passive smoking is equally hazardous for health and more than 3400 deaths each year are attributed to lung cancer as a result of passive smoking by non-smokers. Likewise, an additional 42,000 death due to cardiovascular reasons is also linked to second-hand smoke inhalation by non-smokers (2).

References:

1. Siegel, R. L., Jacobs, E. J., Newton, C. C., Feskanich, D., Freedman, N. D., Prentice, R. L., & Jemal, A. (2015). Deaths Due to Cigarette Smoking for 12 Smoking-Related Cancers in the United States. JAMA internal medicine.

2. Giovino, G. A., Mirza, S. A., Samet, J. M., Gupta, P. C., Jarvis, M. J., Bhala, N., ... & GATS Collaborative Group. (2012). Tobacco use in 3 billion individuals from 16 countries: an analysis of nationally representative cross-sectional household surveys. The Lancet, 380(9842), 668-679.

3. Popova, L., & Ling, P. M. (2013). Alternative tobacco product use and smoking cessation: a national study. American journal of public health, 103(5), 923-930.