Epidemiology of active tuberculosis in lung cancer patients: a systematic review.

Objectives: The aim of this review article is to evaluate the available literature concerning the prevalence of active tuberculosis in lung cancer patients.

Data Source: MEDLINE, PubMed, EMBASE and Medscape databases were searched for studies with quantitative data on the interaction between tuberculosis (TB) and lung cancer, published since 1952. We used the Medical Subject Headings' term 'tuberculosis' and the text-word terms 'TB' and 'Mycobacterium infection', and also, the Medical Subject Headings' terms 'neoplasm' and 'lung neoplasm', or the text-word term 'lung cancer'.

Data Selection: We selected studies with cases verified by bacteriological examinations and biopsies that contained enough data to estimate tuberculosis prevalence. We did not exclude any study on the basis of language.

Results: The prevalence of active tuberculosis among lung cancer patients varies depending on spatial and regional factors. Lung cancer patients who are more prone to developing tuberculosis are Asian and Caucasian males, with an average age of 60 years old. The prevalence of tuberculosis is higher in patients with chest X-ray evidence of old tuberculosis and/or history of tuberculosis, chronic obstructive pulmonary disease, heavy cigarette smoking, increased alcohol consumption, and/or diabetes mellitus. A high mortality rate because of tuberculosis in lung cancer patients was also estimated.

Conclusion: Active tuberculosis complicating lung cancer is a significant clinical issue in countries with high prevalence of tuberculosis. However, as the there is a lack of reports from developed countries over the last 20 years, the significance of this interaction in countries with low tuberculosis burden remains controversial.