Evaluation of Larynx cancer risk ratio in Smokers and Nonsmokers : A systematic review

Laryngeal cancer means the malignant degeneration of epithelial tissue or from the connective tissue, which starts in the constitutive elements of the larynx. Laryngeal cancer is one of the most common cancers of the upper aerodigestive tract with an incidence of ۲.۷۶ cases/year per ۱۰۰,۰۰۰ inhabitants and ۱.۶۶ deaths/year per ۱۰۰,۰۰۰ inhabitants during the past ۳ decades in the world. Many studies have shown the effect of smoking cessation on the risk of lung cancer, and have demonstrated that the incidence tends to decrease at the time of stopping, Thus, although former smokers have a higher risk ratio than never-smokers, they also have a substantially lower risk ratio as compared to continuous smokers, the risk ratio declining with increasing time since smoking cessation. In this article review, we aim to evaluate the laryngeal cancer risk in smokers and non(ex) smokers. Methods: This study was based on Prisma guidelines. To conduct this review, we carried out a detailed search in many databases including Google Scholar, Pubmed and SCOPUS with keywords “larynx”, “cancer”, “smoking”, “non-smoking” and “Laryngeal cancer” from ۲۰۰۰ to ۲۰۲۴. There were no language restrictions and studies investigating the relevance between laryngeal cancer and smoking cessation were included. Results: Based on the entry and exclusion criteria,۳۰۰ articles were identified, which were related to the chosen title. By removing press review articles, systematic narratives, conference abstracts and such, ۱۵ articles were chosen. All ۱۵ articles were clinical trials and the analysis on the effects of smoking cessation and laryngeal cancer was based on multiple hospital databases. All of these studies reported a positive relation between smoking and laryngeal cancer and comparing ex-smokers with current smokers shows a lower risk ratio in ex-smokers and a significantly lower risk ratio in never-smokers. Discussion: According to the studies conducted, a large number of epidemiological studies indicate that the risk of laryngeal cancer is reduced in ex-smokers as compared to subjects who continue to smoke and it is substantially lower in never-smokers. Cigarette smoking does generate reactive oxygen species, which are capable of inducing DNA double-strand breaks (DSBs) which is the most serious DNA damage, and if not repaired, it might result in genomic instability, cancer transformation or cell death. The favorable effect of stopping smoking is evident in these studies and confirms that smoking does increase the risk ratio of laryngeal caner.

کلیدواژه ها:

larynx ، cancer ، smoking ، non-smoking ، Laryngeal cancer