167P - Five-years incidence of SCLC and analysis of PM2.5 air pollution in the province of Brescia: Preliminary results

Background

Air particulate matter with diameter less than 2.5 μm (PM2.5) has been advocated as a lung cancer (LC) carcinogen. From recent data, the city of Brescia in Northern Italy has one of the highest PM2.5 concentration among European cities. The incidence of Small Cell Lung Cancer (SCLC) is decreasing in Western countries. However, data on SCLC incidence and its relationship with air pollution are lacking in the province of Brescia.

Methods

We analyzed data of patients (pts) with a new diagnosis of SCLC or high-grade neuroendocrine lung cancer observed from January 2017 to December 2021 at the Spedali Civili of Brescia, the major community hospital in the province. The Brescia province was segmented in 7 geographical areas and incidence of SCLC was calculated on the 2021 population of 1 253 545 individuals. Associations between clinical variables including smoking habits, toxic exposure risk activity, PM2.5 concentrations and SCLC incidence were studied in the same timeframe and areas.

Results

We identified 188 new cases of SCLC (24% limited disease, 76% extensive disease) representing 12% of all new LCs. Sites with higher incidence were the Brescia city or hinterland (62 pts) and the South Brescia area (38 pts). Median age was 69.3 years. More than 92% of pts were current or former smokers with a median of 45 pack/years, >20% of pts had toxic exposure risk activity and 45.2% of pts had both risk factors. Median overall survival from diagnosis was 8.5 months. The median annual incidence rate was 2.87 new cases/100 000 people (range 2.55–3.51) with an incremental rate of 0.24 cases/year from 2017 to 2021. In the same period PM2.5 concentrations in the whole province dropped from 27 to 21 μg/m³. SCLC incidence was higher in areas with the highest PM2.5 concentrations.

Conclusions

This study is the first report of specific SCLC incidence, trend and association with air pollution in the highly industrialized Brescia province. In the 5 years of observation, concentrations of PM2.5 decreased below the limit value of 25 μg/m³ according to the Italian regulations but above the WHO recommended value of 10 mg/m³. Correlation of SCLC incidence and PM2.5 concentrations is a preliminary result of concern that requires extensive validation.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.