Objective  To evaluate the prognostic value of response evaluation criteria in lymphoma (RECIL) 2017 in patients with diffuse large B-cell lymphoma (DLBCL).

Methods The imaging data and clinical data of 108 patients with DLBCL treated in the Fourth Hospital of Hebei Medical University from August 2013 to August 2021 were analyzed retrospectively, including 49 males and 59 females, aged (49.5±17.0) years. All patients underwent ¹⁸F-fluorodeoxyglucose (FDG) PET/CT imaging using two kinds of PET/CT scanner after chemotherapy. In accordance with RECIL 2017, the patients were divided into complete response (CR), partial response (PR), minor response (MR), stable disease (SD), and progressive disease (PD). The progression-free survival (PFS) rate and overall survival (OS) rate of the patients at 1, 3, and 5 years after chemotherapy were analyzed by follow-up analysis. Pearson's chi-squared test and Mann-Whitney U test were applied in the comparision of ¹⁸F-FDG PET/CT parameters and clinical data. Univariate analysis and multivariate Cox proportional risk regression analysis were used to screen the influencing factors of 5-year PFS and OS rates after chemotherapy in patients with DLBCL. Kruskal-Wallis test was used to compare the PFS and OS time among patients with different therapeutic effects. Kaplan-Meier survival curve was used to assess the differences in PFS and OS rates between RECIL 2017 and Lugano standards at 1, 3, and 5 years. Log-rank test was used to analyze the differences in patients with different therapeutic effects evaluated by RECIL 2017. Kappa test was used to evaluate the consistency between RECIL 2017 and Lugano standard, and Mann-Whitney U test was used to compare the differences in sum of longest diameters (SLD) of target lesions shown by two kinds of PET/CT imaging before and after chemotherapy.

Results The median follow-up time for all patients was 41.4(31.5, 54.1) months. The 1-year PFS and OS rates were 89.8%(97/108) and 100%(108/108); the 3-year PFS and OS rates were 64.8%(70/108) and 84.3%(91/108), respectively; and the 5-year PFS and OS rates were 63.0%(68/108) and 74.1%(80/108), respectively. In 108 patients, 52 cases achieved CR, 13 cases achieved PR, 11 cases achieved MR, 12 cases achieved SD, and 20 cases achieved PD. Univariate analysis showed that the Eastern Cooperative Oncology Group physical state score and the international prognostic index were the influencing factors of 5-year PFS and OS rates in patients with DLBDL (χ²=4.592−10.763, all P<0.05). Multivariate Cox proportional risk regression analysis showed that RECIL 2017 was the influencing factor of 5-year PFS (relative risk (RR)=1.582, 95%CI: 1.268−1.972, P<0.001) and OS rates (RR=1.683, 95%CI: 1.282−2.210, P<0.001) in patients with DLBCL after chemotherapy. According to RECIL 2017 and the Lugano standard, different treatment responses (CR, PR, MR, SD, PD) were the influencing factors of PFS rate (χ²=25.437−31.752, all P<0.001) in patients with DLBCL at 1, 3, and 5 years after chemotherapy and OS rate (χ²=23.836, 32.900; all P<0.001) at 3 and 5 years after chemotherapy. Differences between PFS time(34.2(22.4, 48.0) months) and OS time (41.4(31.5, 54.1) months) of DLBCL patients were statisticaly significant (H=22.573, 12.366; both P<0.05). A strong consistency was found between the Lugano criteria and RECIL 2017 in evaluating the efficacy of patients with DLBCL after chemotherapy (Kappa=0.621, P<0.001). SLD of target lesions shown by two kinds of PET/CT scanner before and after chemotherapy (9.65(4.18, 18.20) cm vs. 7.55(1.90, 14.05) cm; 3.65(0.00, 10.23) cm vs. 3.05(0.00, 7.15) cm) were not statisticaly significant (Z=−1.451, −0.898; both P>0.05).

Conclusion RECIL 2017 can accurately evaluate the prognosis of patients with DLBCL after chemotherapy.