Relationship between Environmental Factors and Cancer: A Systematic Review on Environmental Carcinogens and Lung Cancer

Abstract

The risk of lung cancer continues to elevate for both smokers and never-smokers. With the increasing morbidities and mortalities related to lung cancer, there is much interest on establishing other confounding factors that lead to lung cancer, other than smoking which is the most common cause. Some of the environmental factors have been identified as potential lung cancer causes. Therefore, the aim of this systematic review is to assess the relationship of environmental factors and lung cancer incidences by investigating various carcinogenic risks exposures that predispose an individual to lung cancer. The objective of this systematic review is thus to assess the evidence of relationship between environmental carcinogens and lung cancer incidence by systematically reviewing relevant studies. A standard criterion for the review methodology was formulated to guide the review process and data extraction. Online databases like PubMed, MEDLINE, Scopus (EMBASE), Google Scholar, Web of Science, and CINAHL were systematically searched for articles published between 2000 and 2021 that explored potential environmental carcinogens that were believed to expose occupational workers and individuals within the environment with lung cancer risks. 25 studies were eligible based on the selection criteria, and were finally included in the systematic review among which four were case-control studies, seven were cohorts, five was prospective, four were previous systematic reviews and four were systematic analysis. Chemical exposures like pesticides were analyzed for their carcinogenesis. Air pollution was also discussed with particulate and coal being the core of evidence of association with lung cancer. Second hand smoke, Asbestos, metal compounds like copper, PVC dust particles and ionizing radiations also provided evidence of environmental carcinogenesis associating to lung cancer cases.