Effect of coexisting advanced extrapulmonary solid cancer on progression of Mycobacterium avium complex lung disease

Although Mycobacterium avium complex (MAC) lung disease has been shown to be associated with lung cancer and hematologic malignancies, there have been few studies of its relationships with other types of cancer. The aim of this study was to assess the effect that coexisting advanced extrapulmonary solid tumors have on the progression of MAC lung disease.

This was a retrospective study of patients diagnosed with MAC lung disease, on the basis of the American Thoracic Society (ATS) criteria, between October of 2005 and March of 2019. The patients were divided into three groups: those with advanced-stage cancer (A-SC group); those with early-stage cancer (E-SC group); and those without cancer (control group). Progression of MAC lung disease was defined as exacerbation seen on imaging. Patient characteristics and the time to progression were compared among the three groups.

A total of 286 patients met the ATS diagnostic criteria for MAC lung disease, and 128 of those were excluded. Of the remaining 158 patients, 20 (7.0%) were in the A-SC group, 36 (12.6%) were in the E-SC group, and 102 (35.7%) were in the control group. The median time to progression in the A-SC, E-SC, and control groups was 432, 3,595, and 2,829 days, respectively (p < 0.01). A proportional hazards model showed that the significant predictors of MAC lung disease progression were advanced-stage cancer (hazard ratio [HR] = 6.096; 95% CI: 2.688-13.826; p < 0.01), cavitary lesions (HR = 2.750; 95% CI: 1.306-5.791; p < 0.01), and a high Nodule-Infiltration-Cavity-Ectasis score (HR = 1.046; 95% CI: 1.004-1.091; p = 0.033).

A coexisting advanced extrapulmonary solid tumor could hasten the progression of MAC lung disease.