Metabolic tumor volume by positron emission tomography/computed tomography as a clinical parameter to determine therapeutic modality for early stage Hodgkin's lymphoma

Abstract

Recent studies have shown that metabolic tumor volume (MTV) by positron emission tomography/computed tomography (PET/CT) is an important prognostic parameter in patients with non-Hodgkin's lymphoma. However, it is unknown whether doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) alone in early stage Hodgkin's lymphoma would lead to similar disease control as combined modality therapy (CMT) using MTV by PET/CT. One hundred and twenty-seven patients with early stage Hodgkin's lymphoma who underwent PET/CT at diagnosis were enrolled. The MTV was delineated on PET/CT by the area ≥SUV(max), 2.5 (standardized uptake value [SUV]). Sixty-six patients received six cycles of ABVD only. The other 61 patients received CMT (involved-field radiotherapy after 4-6 cycles of ABVD). The calculated MTV cut-off value was 198 cm(3) . Clinical outcomes were compared according to several prognostic factors (i.e. age ≥50 years, male, performance status ≥2, stage II, B symptoms, ≥4 involved sites, extranodal site, large mediastinal mass, CMT, elevated erythrocyte sedimentation rate and high MTV). Older age (progression-free survival [PFS], P = 0.003; overall survival [OS], P = 0.007), B symptoms (PFS, P = 0.006; OS, P = 0.036) and high MTV (PFS, P = 0.008; OS, P = 0.007) were significant independent prognostic factors. Survival of two high MTV groups treated with ABVD only and CMT were lower than the low MTV groups (PFS, P < 0.012; OS, P < 0.045). ABVD alone was sufficient to control disease in those with low MTV status. However, survival was poor, even if the CMT was assigned a high MTV status. The MTV would be helpful for deciding the therapeutic modality in patients with early stage Hodgkin's lymphoma.

Figure 1

Comparisons of survival according to treatment strategy or metabolic tumor burden using ¹⁸F‐fluoro‐deoxyglucose positron emission tomography (¹⁸F‐FDG‐PET) in patients with early stage Hodgkin's lymphoma (HL). In a median follow‐up time of 45.8 months, progression‐free survival (PFS) and overall survival (OS) in the combined modality treatment (CMT) group were not significantly different with the doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) only group (PFS, 91.8% in the CMT group vs 80.3% in the ABVD only group, P = 0.056 [a]; OS, 91.8% in the CMT group vs 84.8% in the ABVD only group, P = 0.151, [b]). The PFS and OS were higher in the low metabolic tumor volume (MTV) group compared with that in the high MTV group (PFS, 96.3% in the low MTV group vs 66.7% in the high MTV group, P < 0.001 [c]; OS, 97.6% in the low MTV group vs 71.1% in the high MTV group, P = 0.001 [d]).

Figure 2

Comparisons of survival according to treatment strategy and metabolic tumor volume (MTV) using ¹⁸F‐fluoro‐deoxyglucose positron emission tomography (¹⁸F‐FDG‐PET) in patients with early stage Hodgkin's lymphoma (HL). Progression‐free survival (PFS) and overall survival (OS) were not different in the low MTV group regardless of the treatment strategy (PFS, P = 0.667 [a]; OS, P = 0.911 [b]). The PFS in the low MTV group was higher than that in the high MTV group treated with combined modality therapy (CMT) (P = 0.012) and OS in the low MTV group was also higher than that in the high MTV group treated with CMT (P = 0.045). The PFS in the high MTV group treated with CMT was higher than that in the group treated with doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD) alone (P = 0.014). However, the difference in OS between the two groups was not significant (P = 0.055).