Advancing Education, Research, and Quality of Care for the Head and Neck oncology patient.
Program Number: B164
Session Name: Poster Session
Particulate Matter Air Pollution as a Risk Factor for Laryngeal and Upper Aerodigestive Tract Malignancies: a Meta-Analysis
Hamzah Jehanzeb; Abrahim D Durrani; Eman Anwar; Muhammad M Arif; Syed M Nawab; Hamdan A Pasha; Aga Khan UniversityObjectives: This meta-analysis aims to quantify the correlation between outdoor particulate-matter air pollution and the incidence of malignancies of the larynx and upper aerodigestive tract.
Materials and Methods: We conducted extensive search of PubMed, Cochrane Library, CINAHL, and Scopus databases from inception through October 2024. Search terms included “air pollution”, “particulate matter”, “outdoor”, “traffic related air pollution”, “larynx”, “oral cavity”, “nasal cavity”, “pharynx”, “cancer”, and other related terms. There were no language restrictions. Studies were included if they assessed the association between particulate-matter air pollution (PM2.5, PM10) and larynx and upper aerodigestive tract cancers. We excluded studies focused on confounding carcinogenic exposures (e.g., tobacco and alcohol), workspace hazard exposures, and indoor air pollution. Two independent reviewers reviewed the studies for inclusion.
Data extraction followed PRISMA guidelines and included variables such as air pollution levels (PM2.5 and PM10), and type and site of cancer, study design, sample size, and duration of the study. For each study a “high pollution” and a “low pollution” category were determined, based on the strata with the highest and lowest particulate matter exposures respectively. The relative risk (RR) of developing malignancies between these two groups was collected and used in our analysis. An inverse-variance random-effects model was used to pool study data. We carried out subgroup analyses for each anatomical site. All analyses were carried out in RevMan version 5.4.1.
Results: Our search strategy yielded a total of 2,661 studies after removal of duplicates. After screening of abstracts and full-texts, 13 studies were included. Our analysis revealed a significantly increased risk of laryngeal malignancies [RR:1.54, 95% CI: 1.04-2.30, degrees of freedom (df):7, I2:99%], cancers of the oral cavity [RR:1.17, 95% CI: 1.05-1.29, df:6, I2:83%], and nasopharyngeal cancer [RR:1.72, 95% CI: 1.11-2.68, df:4, I2: 93%] associated with particulate-matter exposure from outdoor air pollution. Moreover, there was also a significantly increased overall risk for developing any upper aerodigestive tract cancer [RR:1.31, 95% CI: 1.12-1.52, df:25, I2:98%]. However, we could not determine any significant association for nasal cavity cancers in our analysis [RR:0.83, 95% CI: 0.44-1.59, df:1, I2:85%]. Moreover, since there was only one study reporting poolable values for cancers of the hypopharynx, oropharynx, tonsils, and salivary glands, a separate subgroup analysis could not be carried out for these malignancies, and they were instead included in our analysis of overall risk of any upper aerodigestive tract cancer.
Conclusions: Our meta-analysis revealed a significant positive association between particulate matter exposure from outdoor air pollution and an increased risk of larynx and upper aerodigestive tract cancers. These findings highlight the importance of air pollution as a risk factor for laryngeal cancer and other head and neck cancers. It also underscores the importance of public-health and environmental interventions for the prevention of laryngeal cancer and other aerodigestive tract cancers, and offers valuable insights to guide clinicians and public health officials in implementing preventive strategies and effectively communicating risks to patients, particularly in high-exposure areas.