Lung cancer epidemiology among the Bahraini population, 1998-2011.

BACKGROUND: Lung cancer is the fourth most common cancer in the Gulf Cooperation Council countries among males and the third among females. It is the commonest cancer among Bahraini males accounting for 16.9% of all cancers and the third in Bahraini females contributing to 5.8 % of all female cancers. The aim of this study was to describe the epidemiology of lung cancer among the Bahraini population during the period 1998-2011.

METHODS: All Bahraini registered lung cancer cases in the national cancer registry from 1 January 1998 to 31 December 2011 were included in the study. Incidence rates were calculated using the CANREG software, in which the annual crude incidence rates, age specific incidence rates and the age standardized incidence rate (ASR) were computed.

RESULTS: Six hundred sixty-four lung cancer cases (72.4%, males and 27.6% females) were diagnosed during the study period. The annual average number of cases was 47.5 per year. The mean age at diagnosis during the study period was 68.7±11.7 years. The average annual ASR was 26.1/100,000 among males and 10.0/100,000 among females. There was a tendency for a decreased trend of the ASR during 1998-2011 in both sexes. Twenty-six percent of lung cancer cases were squamous cell carcinoma and 17.9% adenocarcinoma. The grades of 70.3% were unknown and 13.4% were poorly differentiated. The stage was unknown for 65.0% of the cases, while 18.5% had distant metastasis and 9.8% were localized. The majority (88.9 %) of the lung cancer cases were dead by the end of the study period with a five-year survival rate of 3.0%.

CONCLUSION: A welcomed decline in the incidence of lung cancer has been noted over the past 14 years. However, more efforts should be put to reduce the proportion of lung cancer cases with unknown stage and grade. The incidence of histological types, which are strongly dependent on tobacco smoking, notably small cell, squamous cell and large cell carcinomas, accounted for over one third of lung cancer cases. Future research should be directed towards better understanding of the lung cancer risk factors and the effectiveness of tobacco control measures in in the country.