Implementation of a Routine Screening Program for Latent Tuberculosis Infection among Patients with Acute Leukemia at a Canadian Cancer Center

Indolent infections in patients with hematologic malignancy: A single-center experience screening for tuberculosis and strongyloidiasis prior to cytotoxic therapy in Boston

Individuals with hematologic malignancy have increased risk of latent tuberculosis infection (LTBI) reactivation and Strongyloides stercoralis (SS) dissemination. However, screening prior to chemotherapy or corticosteroids is not routine. We conducted a LTBI and SS screening intervention amongst patients with hematologic malignancies. Over one-third immigrated from countries with high TB incidence and SS prevalence, and some had additional risk factors (HIV, HTLV-1, eosinophilia). The intervention increased screening rates but universal screening was not achieved. Screening positivity was similar pre- and post-intervention. We demonstrate a population with increased indolent infection reactivation risk. Specific infectious screening guidelines are needed to prevent significant morbidity.

Screening and treatment of latent tuberculosis in patients with solid tumors and systemic cancer therapy

INTRODUCTION

Tuberculosis is one of the infectious diseases with greater morbidity and mortality worldwide. Cancer causes an important immunosuppression with increased risk of infections. There is an enlarged bidirectional incidence between tuberculosis and cancer, mainly due to latent tuberculosis.

GUIDELINES REVIEW

There is great discrepancy between recommendations for screening and prophylaxis of latent tuberculosis in patients with solid tumors and systemic cancer therapy among different medical societies and guidelines. Most infectious diseases guidelines recommend it, while most oncology guidelines do not.

DISCUSSION

Patients with solid tumours generally have a limited life expectancy and a state of intermittent immunosuppression, resulting in a lower risk of tuberculosis reactivation than other risky populations. There is a lack of prospective and retrospective studies analysing the benefit of screening and prophylaxis in this population. The first step is to study the incidence of active tuberculosis in this population to estimate the real magnitude of the problem.

Acute Leukemia and Latent Tuberculosis Infection in Italy: Quantiferon-Tb Test Screening in a Low Tuberculosis Incidence Country

Background

Identification of latent tuberculosis infection (LTBI) is a critical step of tuberculosis surveillance, especially in low-incidence countries. However, it is limited to situations with a higher probability of developing active disease, e.g., patients with hematological malignancies. According to guidelines, in TB non-endemic countries, no clear screening program is established at diagnosis for patients with acute leukemia (AL). The primary endpoint of this study was to establish the prevalence of LTBI in patients with a diagnosis of AL using QuantiFERON (QFT)-TB. Secondarily, radiological and clinical features driving the increased risk of LTBI were evaluated.

Methods

QFT-TB screening was performed before induction or consolidation in all patients with AL (myeloid and lymphoid) treated at our Institution between October 2019 and August 2023.

Results

We accrued 62 patients, of whom 7 (11,3%) tested positive, without any symptoms or signs of active TB, and 2 (3,2%) resulted as indeterminate. All positive patients started prophylaxis with isoniazid 300 mg daily, while patients whose test was indeterminate did not receive any prophylaxis. Active TB was excluded by imaging, as well as microscopic, cultural, and molecular examination on bronchoalveolar lavage if signs of any infection were detected. During the 46 months of observation, no patients developed TB reactivation.

Conclusions

Despite the low sample size, 1/10 of our patients had prior TB exposure, hinting that LTBI could be more common than expected in Italy. This finding suggests implementing TB screening in the pre-treatment setting, particularly at a time when more active treatments are becoming available also for patients ineligible for intensive chemotherapy.