The Effect of Fine (PM2.5) and Coarse (PM10-2.5) Particulate Matter on Survival Outcomes in Nasopharyngeal Carcinoma Patients: A Retrospective Cohort Study in a Northern Thailand Tertiary Care Center

Objective: This study aimed to examine the association between exposure to ambient fine (PM2.5) and coarse (PM10-2.5) particulate matter and survival outcomes among patients with nasopharyngeal carcinoma. Methods: A retrospective study was conducted among patients with nasopharyngeal carcinoma. Annual mean levels of ambient particulate matter and gaseous air pollutants were assessed from the Thailand Pollution Control Department. The Cox proportional hazards model was used to estimate the association between exposure to PM2.5 and PM10-2.5, categorized into four concentration quartiles, and survival outcomes. Results: One hundred and forty patients were included. Five-year overall survival (OS) and disease-free survival (DFS) were 73.1% and 61.9%, respectively. Univariable and multivariable analyses showed that increased PM2.5 exposure was not significantly associated with OS or DFS. In multivariable analysis, higher PM10-2.5 exposure categories were associated with poorer survival outcomes. Compared with patients in the lowest exposure quartile, those in the highest PM10-2.5 exposure quartile demonstrated significantly poorer OS (aHR 8.12, 95% CI 1.30–15.27) and DFS (aHR 9.17, 95% CI 4.58–13.98) when comparing the 4th with the 1st quartiles of concentration. Conclusions: High exposure to PM10-2.5 was associated with an increased risk of death and disease recurrence in patients with nasopharyngeal carcinoma, with statistically significant associations observed between the highest and lowest exposure quartiles.