It is known that patients with tuberculosis in anamnesis have an increased risk of lung cancer development. Shorter survival of patients with diagnosed lung cancer preceded by an active form of tuberculosis has also been stated. On the basis of data accessible in the literature, a close relation between these two morbidities is observed. The question of which disease develops first is still unanswered. There are studies suggesting that tuberculosis might support cancer development by evoking an inflammatory reaction and fibrosis in involved tissue, leading subsequently to neoplastic transformation. Adversely, other studies claim that lung cancer is a risk factor of tuberculosis, probably by causing immunity decrease, which increases the risk of new infection development or reactivation of an old one.

In our study, a case of 61-year-old woman with diagnosed tuberculosis in the course of non-small cell lung cancer treated with chemotherapy is presented. The tuberculosis was diagnosed on the basis of positive bacteriological findings in material obtained during a bronchofiberoscopy and a positive result of a QuantiFERON TB-Gold test in blood serum. The depicted case confirms that the coexistence of tuberculosis and lung cancer worsens the patient’s prognosis, causes significant problems with diagnosis and impairs the effectiveness of cytostatic treatment.