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

Abstract

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.

Keywords: Epidemiology; Small Cell Lung Carcinoma; Survival.

Figure 1.

SCLC trends (overall and by gender) from 2009 to 2019 in the study population. The Chi-Square test showed no statistically significant difference between males and females (P-value =0.887)

Figure 2.

The trend of smoking status by gender during the study period. Smoking status has statistically significant trend changes in the Chi-Square test only in males (P-value<0.001) but has not changed in females (P-value=0.593)

Figure 3.

The Kaplan-Meier survival curve from overall survival (OS) in the study population

Figure 4.

The means and medians of overall survival (OS) from 2009 to 2019. The Log-rank test showed a statistically significant difference between means and medians of OS during the study period (P- value= 0.007)