Prognostic value of interim and post-therapy 18F-FDG PET/CT in patients with diffuse large B-cell lymphoma

Abstract

Objective To investigate the prognostic value of interim and post-therapy 18F-FDG PET/CT in patients with DLBCL. Methods A retrospective analysis was conducted in 110 patients (62 males, 48 females; median age 52 years) with newly diagnosed DLBCL. Forty-two patients underwent interim PET/CT after 4 cycles chemotherapy, 44 patients underwent post-therapy PET/CT after 6-8 cycles of chemotherapy, and 24 patients underwent both interim PET/CT and post-therapy PET/CT. Interim and post-therapy PET/CT status (i.e., positive or negative) were visually interpreted according to criteria of the International Harmonization Project. Three-year progression-free survival (PFS) and 3-year overall survival (OS) was compared between the subjects with positive or negative PET/CT results. χ2 test and Kaplan-Meier analysis were used for data analysis. Results Interim 18F-FDG PET/CT results were positive in 28 cases and negative in 38 cases. The median PFS and OS were 20 and 28 months in patients with positive scan results, those were 37 and 39 months in patients with negative results, respectively. Three-year PFS and 3-year OS rates were 17.9%(5/28) and 35.7%(10/28) in patients with positive interim PET/CT results, those were 52.6%(20/38) and 55.3%(21/38) in patients with negative results(χ2=8.285, P 0.05, respectively). Post-therapy 18F-FDG PET/CT results were positive in 20 cases and negative in 48 cases. Median PFS and OS were 21 and 26 months in patients with positive results, those were 54 and 57 months in patients with negative results. Three-year PFS and 3-year OS rates were 20.0%(4/20) and 25.0%(5/20) in patients with positive results at post-therapy PET/CT, those were 77.1%(37/48) and 83.3%(40/48) in patients with negative results (χ2=19.215, 21.462, both P<0.01). Conclusions Post-therapy 18F-FDG PET/CT is useful to predict prognosis of patients with DLBCL. However, the value of interim PET/CT may be limited in terms of prognosis prediction. Key words: Lymphoma, large B-cell, diffuse; Drug therapy; Tomography, emission-computed; Tomography, X-ray computed; Deoxyglucose