Background & Objective: Lung cancer is one of the most common cancers in the world and is considered as one of the top five cancers in Iran. The aim of this study was to evaluate the epidemiology and risk factors for lung cancer in Ardabil.

  Methods: This cross-sectional study was done in Ardabil province since May 2009 to May 2011. Subjects were evaluated from two sources the first group was selected from patients of the Imam Khomeini hospital of Ardabil. These patients were underwent bronchoscopic biopsy in this center and their pathological reports were positive for primary lung cancer. The second group included the patients were reported in Ardabil cancer registry center with diagnosis of primary lung cancer and their samples have been sent to the other centers for analysis. We collected the data in a data sheet for each group separately and analyzed through the use of SPSS (ver. 16) statistical package.

  Results: A total of 124 patients with lung cancer enrolled in this study (79% in the first group and 21% in second group). The male gender was dominant among the patients (82.3%) and the mean age of 64.23±9.99 years. In the first group more than half of the patients (54.1%) were urban, 90.8% had a history of smoking (mean 38.67±25.70 packs of cigarettes per year) and the history of opium abuse was high among subjects (34.7%), the positive family history of cancer was 17.3%, and the most common chief complaint at the time of diagnosis was bloody sputum (32.7%). Right upper lobe was the most common site of cancer in bronchoscopy of this group (27.64%) and squamous cell carcinoma was the most common form of malignancy (61.3%).

  Conclusions: This study showed that unlike developed countries and in line with domestic studies, squamous cell carcinoma was the most common lung cancer, and adenocarcinoma was less common. Lung cancer among the men was seen 4.6 times more than women, and smoking was the most important risk factor.