The predictive value of PET/CT for progression of malignant lymphoma: A retrospective analysis after first line therapy

Objectives The most widely acceptable role for PET is in restaging patients following the completion of therapy. Several studies have suggested a high negative predictive value for PET/CT in malignant lymphoma, recently. The persistence of a mass after the completion of first line treatment may pose some diagnostic difficulties. Approximately two-thirds of patients suffering from Hodgkin lymphoma (HL), and about half of those with aggressive diffuse large B-cell lymphoma present with residual mass after the completion of therapy. Additionally, approximately 30 % of patients will relapse. Our study aimed to test the predictive value of PET/CT for progression.

Methods Clinical data of 43 patients who underwent PET/CT between August 2005 and July 2006 after finishing their planned treatment were analyzed, retrospectively. Twenty-two patients presented with HL and 21 patients with NHL. The clinical and/or pathological follow-up data were reviewed and related to PET/CT findings.

Results The sensitivity, specificity, positive predictive value, and negative predictive value was 75 %, 91%, 67 %, and 94 %, respectively.

Conclusions FDG PET/CT has a high impact on the management of patients with malignant lymphoma. Our results confirm the high negative predictive value of PET/CT in the post-treatment evaluation of lymphoma. It is a promising predictor for disease-free survival. However, positive findings must be carefully analyzed; biopsy and thorough observation of these patients is highly recommended.