Epidemiology and histopathological classification of lung cancer: A study from Jordan, retrospective observational study.

Background: Lung cancer is a major health burden in Jordan. With the failure of tobacco control policies and the evolution of new smoking methods like water pipes and e-cigarettes, lung cancer is projected to further increase. This study investigates the epidemiology and the different histopathological subtypes of lung cancer in correlation with age, sex and smoking.

Material And Methods: 434 tumors diagnosed in the main tertiary hospital in Northern Jordan throughout the period of 2004-2017 were included. Specimens were tested by H&E and immunohistochemical stains. Clinical data were collected from patients' medical files. IRB approval number 310/2016 was granted by Jordan University of Science and Technology review board.

Results: 86.9% of cases were males compared to 13.1% in females obtaining a male:female ratio of 6.6:1. The mean age was 63.8 years with a range of 28-103 years. Prevalence of cases increased with increasing age and smoking. Histopathologically, adenocarcinoma accounted for over half of the cases followed by Squamous cell carcinoma (SCC) and neuroendocrine tumors (NET) in both sexes. Adenocarcinoma had the lowest mean age; 62.74 years, while SCC had the highest mean age with 65.42 years. All subtypes increased with age but in different degrees. The increase was more pronounced in SCC and NET and less with adenocarcinoma. Adenocarcinoma was more common in both smokers and non-smokers. However, smokers to non-smokers ratio differed; where it was the highest in NET (6:1) compared to 4:1 in SCC and 2:1 in adenocarcinoma.

Conclusion: Median age of our patients was slightly lower than that previously reported in Jordan. This study also showed an increase in the relative incidence of adenocarcinoma compared to SCC.