Study designs of evaluations included in the review
No inclusion criteria relating to the study design were specified although studies had to include at least 10 patients. Both prospective and retrospective studies were included.
Specific interventions included in the review
Studies of dedicated (ring) PET using FDG were eligible for inclusion. The definition of a positive PET scan varied between studies, and only a minority of studies used a semi-quantitative measurement of FDG uptake.
Reference standard test against which the new test was compared
No inclusion criteria relating to the reference standard were specified. The authors stated that they used the following criteria to determine whether patients had active disease: tumour positive biopsy or clinico-radiological follow-up of at least 12 months in patients without positive biopsies. The reference tests used in the included studies tended to be histopathology of biopsies in a minority of patients and radiological and clinical follow-up in the majority.
Participants included in the review
Studies of patients with histologically proven Hodgkin's disease (HD) or aggressive non-Hodgkin's lymphoma (NHL), who were undergoing evaluation following first-line therapy, were eligible for inclusion. Studies of patients with central nervous system and AIDS-related lymphoma were excluded. The primary studies included populations of patients with broad (patients included regardless of computed tomography findings) and small (only patients with residual masses) spectrum of disease. Where reported, patients had received chemotherapy alone or in combination with radiotherapy. The age of the patients ranged from 2 to 88 years. The prevalence of relapse ranged from 14 to 46%.
Outcomes assessed in the review
No inclusion criteria relating to the outcomes were specified. However, studies that did not report sufficient data to construct a 2x2 table of PET performance were excluded from the meta-analysis. The main outcome measures reported in the review were the sensitivity and specificity.
How were decisions on the relevance of primary studies made?
Two reviewers independently selected studies for inclusion. Any disagreements were resolved through consensus.