Purpose: We investigated the prognostic value of total metabolic tumour volume (TMTV) in diffuse large B-cell lymphoma (DLBCL).
Methods: TMTV was measured in 114 patients with newly diagnosed DLBCL who underwent (18)F-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).
Results: Median follow-up was 39 months. Average pretherapy TMTV was 509 ± 568 cm(3). The 3-year estimates of PFS were 77 % in the low metabolic burden group (TMTV ≤550 cm(3)) and 60% in the high metabolic burden group (TMTV >550 cm(3), 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.
Conclusion: Pretherapy TMTV is an independent predictor of outcome in patients with DLBCL.