Unifying the predictive value of pretransplant FDG PET in patients with lymphoma: a review and meta-analysis of published trials

The predictive value of F-18-FDG PET in patients with relapsing/refractory lymphoma who are receiving high-dose chemotherapy and autologous stem cell transplantation (ASCT) remains a matter of debate. Seminal reports on pretransplant ASCT indicated an adverse prognosis in patients with positive FDG PET scans. The lack of a uniform outcome measure along with the mixed histologies in various studies have hampered efforts to quantify this prognostic value. A MEDLINE review of published trials up to April 2009 identified 16 studies involving pretransplant FDG PET scans in lymphoma. Where progression-free survival (PFS) and overall survival (OS) were set as the main outcome measures, time-to-event data analysis was used to calculate the overall prognostic value of a pretransplant FDG-PET scan. Pooled survival data from seven eligible studies suggested a worse PFS in patients with a positive FDG PET study (HR 3.23, 95% CI 2.14 to 4.87). The OS pooled from six eligible studies was also significantly worse among patients with a positive FDG PET study (HR 4.53, 95% CI 2.50 to 8.22). No statistically significant heterogeneity was observed between studies for either outcome. Despite the documented clinical heterogeneity between studies, meta-analysis data confirmed the prognostic impact of pretransplant FDG PET in patients with lymphoma and provided a uniform measure of the association for both progression and survival after ASCT.