Simultaneous presentation of pulmonary tuberculosis and lung cancer: experience from a regional cancer centre

Abstract

Background: Prevalence of pulmonary tuberculosis is very high in India. Lung cancer is the most common cancer in males in Delhi and because of close similarity in clinical and radiological features of lung cancer and tuberculosis many of lung cancer patients have had received empirical anti tubercular treatment (ATT) before a diagnosis of lung cancer was established. True incidence of pulmonary tuberculosis in lung cancer is not known. Tuberculosis in lung cancer may get reactivated following chemotherapy and/or radiation therapy. Simultaneous presentation of tuberculosis and lung cancer independent of treatment with immunosuppresants, however, is rare. Material and Methods: At our center we evaluated records of 580 lung cancer patients seen over a period of 5 years to see incidence of pulmonary tuberculosis in lung cancer. Patients who had been worked up for pulmonary tuberculosis like sputum or bronchoalveolar lavage (BAL) for AFB smear or culture were identified. Results: Two hundred and ninety eight of these patients were worked up for pulmonary tuberculosis. Twelve patients in the present study had documented evidence of simultaneous existence of pulmonary tuberculosis (acid fast bacilli positive sputum and or culture positivity) and lung cancer. Radiologically, no separate active tubercular lesion was identified except in one patient who had left upper zone fibro parenchymal lesion. Fibrosis and calcification on chest X-rays (CXR) suggestive of old tuberculosis were evident in 7 patients. Eight patients died of progressive lung cancer within 3 months of diagnosis, 4 patients became acid fast bacilli (AFB) negative after 2 months of anti tubercular therapy. Diagnosis of lung cancer was delayed in 4 patients as they were receiving anti tubercular therapy after detection of AFB in sputum. Conclusion: Recognition of tuberculosis is important not only because it is curable but also due to the fact that its presence interferes with radiological assessment to chemotherapy and radiotherapy. Sputum acid fast smear may be done more frequently in patients of lung cancer in countries where tuberculosis has high prevalence. The true incidence may be still higher and newer techniques e.g. PCR based and others may help in knowing true incidence of co existence of lung cancer and pulmonary tuberculosis.