Tuberculosis in oncology patients

There is a dearth of studies addressing the incidence and clinical presentation of tuberculosis (TB) in children with cancer.

To evaluate the incidence of TB in paediatric oncology patients at Tygerberg Hospital, located in a Cape Town area of high TB prevalence, and to describe the clinical characteristics of the disease in this particular group of patients whose treatment typically suppresses their immune response.

We reviewed the records of 625 paediatric oncology patients admitted from 1 January 1991 to 31 December 2005. Of these, 87 received treatment for TB; however, only 57 cases had sufficient data to support a diagnosis of TB and only these were used for further analysis.

In the children with TB, acute lymphoblastic leukaemia (ALL) was the most common malignancy (13/57, 22.8%). The incidence of TB in the study group was 9117/100,000/year, which is 22 times higher than the overall TB incidence reported in children from a similar background. Importantly, 47% of the active infections appeared in the 1st 5 months of chemotherapy, suggesting reactivation of latent TB.

Identifying latent TB in our patients and providing prophylactic treatment during the initial months of chemotherapy might have prevented disease progression in these cases. Routine screening of paediatric oncology patients for latent TB infection and exclusion of active disease prior to initiation of cancer therapy might be indicated in TB-endemic areas.