Targeted Screening of Latent Tuberculosis in Cancer Patients

With approximately 80% of active tuberculosis (TB) cases arising from reactivation of latent TB infection (LTBI), a key national strategy for TB elimination is targeted screening in high-risk groups. Although cancer is considered a high-risk condition for reactivation TB, baseline screening for LTBI is not considered standard care in this population. Targeted screening and treatment in cancer patients can lead to early diagnosis and treatment preventing reactivation and spread of disease. This study evaluated LTBI prevalence in Veteran’s with cancer diagnoses, and compared patient and cancer-specific characteristics that may predict a positive result. Additionally, the use, reliability, and cost effectiveness of screening tests (T-SPOT.TB® and tuberculin skin testing) was examined. LTBI treatment acceptance, adverse events and completion rates were evaluated. Finally, the cost efficacy of targeting and treating LTBI in cancer patients was assessed. A retrospective chart review of cancer patients screened using the T-SPOT.TB® test was conducted between 1/1/2017 through 10/31/2017 from a Veterans Affairs oncology clinic. Descriptive statistics were used. Eight (4.6%) Veterans were screen-positive for LTBI (n=175). The median age was 70.5 years, with majority from the Vietnam service era. No high-risk comorbidities or high-risk behaviors were identified as predictors of positive results. The number needed to screen (NNS) to detect a single LTBI case was 22 ($1,100 per detected case). Indeterminant test results burden was 11/175 (6.3%). Treatment acceptance was 62.5% (n=5) with 20% (n=1) associated adverse events. Cost efficacy comparing NNS to detect a single case with costs associated with TB contact investigations was 20-fold less than the 2012 TB contact investigation. This study adds to the understanding of LTBI prevalence in Veterans with cancer and can guide policy development for evidence-based screening and treatment.