FDG uptake in lymph-nodes of HIV+ and tuberculosis patients: implications for cancer staging

Abstract

Aim: The incidence of non-AIDS-related cancers (NADCs) in the AIDS-population has surpassed that of the general population. HIV significantly increases an individual's chances of reactivation of latent tuberculosis (TB) infection and progression to active TB disease. Both HIV, TB and CA present with increased FDG uptake in involved lymph nodes (LNs). The aim of this study was to assess the existence of quantitative differences in FDG uptake by lymph nodes in HIV+/TB-/CA- patients, TB+/HIV-/CA-, TB+/HIV+/CA- patients and HIV-/TB-/CA+ patients.

Methods: Sixteen consecutive referred patients suffering from HIV-1, 21 suffering from HIV-1 and TB and 16 suffering from TB alone were prospectively included. In addition, 30 consecutively referred, previously untreated, HIV and TB negative cancer patients were included. All patients underwent FDG PET imaging. Mean standardized uptake values (SUV mean values) were obtained for involved lymph nodes using region growing and a threshold of 30% in all patients. Results obtained were compared using non-parametric statistics.

Results: SUVmean values of involved LNs of HIV+/TB+/CA- patients were significantly higher than SUVmean values of involved LNs of HIV-/TB+/CA- patients and HIV+/TB-/CA patients (P<0.05). Also, SUVmean values of involved LNs of HIV-/TB-/CA+ patients were significantly higher than SUVmean values of involved LNs of HIV+/TB-/CA- patients. HIV+/TB+/CA- patients presented with a significantly higher number of sites of LN involvement when compared to the HIV+/TB-/CA- patient group.

Conclusion: FDG PET is not useful for assessing malignant lymph node involvement in HIV+, TB+ or HIV+/TB+ patients.