Epidemiology of lung cancer in northeast of Iran: A 25-year study of 939 patients

Trends in Epidemiology and Outcome of Small Cell Lung Cancer over 10 Years at Tertiary Cancer Care Center in Iran

Background

Lung cancer is the leading cause of cancer death. Among different lung cancer histopathologies, small cell lung cancer (SCLC) has been known to be the most aggressive and lethal nature. This study analyzed the epidemiological characteristics, outcomes, and trends of SCLC at a tertiary cancer care center in Iran.

Materials and Methods

Retrospectively collected demographic characteristics and survival outcome data on histologically proven SCLC patients during 2009-2019 at the National Research Institute of Tuberculosis and Lung Disease (NRITLD) were reviewed.

Results

In a study of 334 SCLC patients, there were more male patients than female, with a ratio of 2.5 to 1, and the mean age at diagnosis was 58.36 years. While gender distribution and smoking status among women remained consistent over the study period, there was a significant increase in male smokers (P<0.001). Female patients were diagnosed at younger age and had a significantly lower proportion of smokers compared to males (P<0.016). The mean and median overall survival were 10.9 and 8.2 months, with one-, two-, and three-year survival rates of 21%, 10%, and 3% respectively. Younger patients and females had significantly higher survival rates. In both uni/multivariate analyses, only age < 58 years and female gender were significantly associated with longer survival.

Conclusion

The relatively unchanged trend of SCLC in our series suggests that further research on prevention strategies especially smoking cessation, early detection, and new treatment options is urgently required.

Impact of Residential Concentration of PM2.5 Analyzed as Time-Varying Covariate on the Survival Rate of Lung Cancer Patients: A 15-Year Hospital-Based Study in Upper Northern Thailand

Air pollutants, especially particulate matter (PM) ≤ 2.5 µm (PM2.5) and PM ≤ 10 µm (PM10), are a major concern in upper northern Thailand. Data from a retrospective cohort comprising 9820 lung cancer patients diagnosed from 2003 to 2018 were obtained from the Chiang Mai Cancer Registry, and used to evaluate mortality and survival rates. Cox proportional hazard models were used to identify the association between the risk of death and risk factors including gender, age, cancer stage, smoking history, alcohol-use history, calendar year of enrollment, and time-updated PM2.5, PM10, NO₂ and O₃ concentrations. The mortality rate was 68.2 per 100 persons per year of follow-up. In a multivariate analysis, gender, age, cancer stage, calendar year of enrollment, and time-varying residential concentration of PM2.5 were independently associated with the risk of death. The lower the annually averaged PM2.5 and PM10 concentrations, the higher the survival probability of the patient. As PM2.5 and PM10 were factors associated with a higher risk of death, lung cancer patients who are inhabitant in the area should reduce their exposure to high concentrations of PM2.5 and PM10 to increase survival rates.