Pretherapy metabolic tumour volume is an independent predictor of outcome in patients with diffuse large B-cell lymphoma

Abstract

We investigated the prognostic value of total metabolic tumour volume (TMTV) in diffuse large B-cell lymphoma (DLBCL). TMTV was measured in 114 patients with newly diagnosed DLBCL who underwent ¹⁸F-FDG PET/CT at baseline before immunochemotherapy. TMTV was computed by summing the volumes of all lymphomatous lesions after applying the local SUVmax threshold of 41 % using semiautomatic software. Prognostic value was assessed by Kaplan-Meier estimates of progression-free survival (PFS) and overall survival (OS). Median follow-up was 39 months. Average pretherapy TMTV was 509 ± 568 cm³. The 3-year estimates of PFS were 77 % in the low metabolic burden group (TMTV ≤550 cm³) and 60 % in the high metabolic burden group (TMTV >550 cm³, p = 0.04), and prediction of OS was even better (87 % vs. 60 %, p = 0.0003). Cox regression showed independence of TMTV for OS prediction (p = 0.002) compared with other pretherapy indices of tumour burden, such as tumour bulk and the International Prognostic Index. Pretherapy TMTV is an independent predictor of outcome in patients with DLBCL.