Pulmonary mycobacterial infections associated with neoplasia

Patients with cancer are at increased risk for disease caused by mycobacteria when there is immunosuppression resulting from the underlying disease or its treatment. Pulmonary disease is usual with Mycobacterium tuberculosis or with mycobacteria other than M tuberculosis (MOTT) and atypical presentations with extrapulmonary dissemination occur frequently. No clinical features reliably distinguish between disease caused by M tuberculosis or MOTT. The incidence of M tuberculosis infection depends on a history of prior exposure in patients and on patterns of disease within hospitals and the surrounding community. Infection with different species of MOTT reflects their environmental prevalence. Diagnosis of mycobacterial infection can be clinically challenging and must be pursued aggressively. Despite recent improvements in clinical and laboratory methods, diagnosis of mycobacterial infection may take weeks. Recent increases in the incidence of M tuberculosis infection and the emergence of drug-resistant strains require heightened alertness to its diagnosis and careful epidemiological control measures to prevent continued spread of this contagion. M tuberculosis with routine antimicrobial susceptibility responds well to conventional therapy when initiated early. Prophylaxis of tuberculin positive patients is effective and should be started before immunosuppressive therapy. Guidelines for therapy of MOTT depend on the species isolated but remains poorly defined in most cases. There are several new compounds that may be useful for treatment of drug-resistant species of MOTT. New methods for the rapid diagnosis, speciation, and epidemiological investigation of mycobacterial infection are being developed, and some are available for clinical application. Nonetheless, the timely diagnosis of mycobacterial disease in patients with cancer remains a challenge of increasing clinical importance.