Evaluation of a routine screening program with tuberculin skin testing on rates of detection of latent tuberculosis infection and prevention of active tuberculosis in patients with multiple myeloma at a Canadian cancer centre.

Background: Chemotherapy-induced T cell dysfunction, resulting from treatment of multiple myeloma (mm), enhances the risk for reactivation of latent tuberculous infection (ltbi). However, routine screening for ltbi has its limitations. The objective of the present study was to assess the number of patients treated for ltbi both before and after the introduction of a consistent tuberculin skin test (tst) screening program for patients with mm at our cancer centre. Methods: This retrospective observational study analyzed adult patients with mm treated with autologous hematopoietic stem-cell transplantation from 1 January 2013 to 31 December 2014, for whom tst was consistently performed at our cancer facility. Baseline demographic characteristics of patients who received tst testing and ltbi therapy were compared with those of a pre-intervention cohort of patients (1 January 2008 to 31 December 2009) who were not tested. Results: During the post-intervention period, 170 patients with mm had a tst. In 14 patients (8.2%) results were positive, and 11 of the 14 received ltbi therapy. Of another 12 patients with radiographic imaging changes consistent with prior granulomatous disease and negative tst results, 2 were treated. No cases of tuberculosis (tb) reactivation were noted in individuals who completed ltbi therapy. One case of active tb was diagnosed in a patient with a negative tst. In contrast, in the pre-intervention matched cohort of 170 patients, no tsts were performed, and no cases of active tb were documented. Conclusions: Patients with mm could benefit from a consistent tst testing policy coupled with subsequent ltbi therapy. However, universal testing might not be required. A targeted program combining evaluation of host risk factors, imaging findings, and screening tests might optimize ltbi diagnosis and management, and thus be effective in preventing the development of active tb in at-risk patients with mm.