This study was done to investigate the role of Interim 18-FDG-PET/CT (i-PET) in predicting the outcome of Diffuse Large B Cell Lymphoma (DLBCL) patients. The Lymphoma registry data base of the Department of Haematology was reviewed for all newly diagnosed DLBCL patients treated with R-CHOP-21 (n = 63). The PET-CT data of these patients at pre-defined time points (baseline, interim and end of treatment) was systematically collected. The predictive accuracy of i-PET-CT (done after 4 cycles R-CHOP-21 chemotherapy) was analysed to define their prognostic importance. 47 patients were eligible for final analysis in this study. According to Deauville’s criteria 15 patients (31%) were positive on i-PET. The positive predictive value (PPV) of i-PET by DS was 73.3%. At a median follow up of 21 months, DS based i-PET negative and positive cases showed significant differences in 2-year OS (81.2% vs 46.7%, p = 0.007) and PFS (75% vs 26.7%, p = 0.005). Combined analysis of i-PET (by DS) and IPI showed negative predictive value (NPV) of 92.3% in Low IPI while PPV of 76.9% in high IPI subgroup of DLBCL. On a multivariate analysis of all prognostic variables, i-PET was found to be independent prognostic marker predicting outcome in DLBCL patients. i-PET is an independent prognostic marker for outcome in DLBCL patients. Combined analysis of Interim PET along with IPI score at diagnosis improves the predictive accuracy of i-PET (both PPV & NPV) and may guide tailoring of therapy in these patients.

本研究旨在调查中期 18-FDG-PET/CT (i-PET) 在预测弥漫性大 B 细胞淋巴瘤 (DLBCL) 患者预后中的作用。对血液科的淋巴瘤登记数据库进行了审查，以了解所有接受 R-CHOP-21 治疗的新诊断 DLBCL 患者（n = 63）。系统地收集了这些患者在预定时间点（基线、中期和治疗结束）的 PET-CT 数据。分析 i-PET-CT（在 4 个周期的 R-CHOP-21 化疗后进行）的预测准确性以确定其预后重要性。47 名患者符合本研究的最终分析条件。根据 Deauville 的标准，15 名患者 (31%) 在 i-PET 上呈阳性。DS 的 i-PET 阳性预测值 (PPV) 为 73.3%。中位随访 21 个月，p  = 0.007) 和 PFS（75% 与 26.7%，p  = 0.005）。i-PET（通过 DS）和 IPI 的联合分析显示，低 IPI 的阴性预测值 (NPV) 为 92.3%，而 DLBCL 的高 IPI 亚组的 PPV 为 76.9%。在所有预后变量的多变量分析中，i-PET 被发现是 DLBCL 患者预后的独立预后标志物。i-PET 是 DLBCL 患者预后的独立预后标志物。中期 PET 与诊断时 IPI 评分的联合分析提高了 i-PET（PPV 和 NPV）的预测准确性，并可能指导这些患者的治疗调整。