Interim PET/CT based on visual and semiquantitative analysis predicts survival in patients with diffuse large B‐cell lymphoma

Abstract

Purpose The role of interim 18 F‐FDG PET/CT (iPET/CT) in diffuse large B‐cell lymphoma (DLBCL) remains controversial. The purpose of this study was to assess the prognostic value of iPET/CT in patients with newly diagnosed DLBCL according to visual and semiquantitative interpretation methods. Methods A total of 129 newly diagnosed DLBCL patients with baseline PET/CT data were retrospectively screened. The iPET/CT findings were evaluated by the Deauville 5‐point scale (DS) and ΔSUVmax. Furthermore, the reduction in SUVmax incorporated with tumor size (ΔSUVmax*ΔSLD) was calculated. The optimal cutoff values of ΔSUVmax and ΔSUVmax*ΔSLD were determined by receiver operating characteristic (ROC) analysis. Kaplan‐Meier analysis was applied to test for the influence of prognostic values. Univariate and multivariate analyses were conducted to examine the potential independent impacts of iPET/CT. Results Seventy‐seven patients with PET/CT images acquired both at baseline and after four cycles of chemotherapy were finally enrolled. The optimal cutoff values for ΔSUVmax and ΔSUVmax*ΔSLD were 74% and 30%, respectively. After a median follow‐up of 23 months, iPET/CT findings were significant predictors of PFS and OS whenever iPET/CT was interpreted by DS, ΔSUVmax, or ΔSUVmax*ΔSLD methods. ΔSUVmax‐based methods were more accurate than those based on DS. The IPI, DS, ΔSUVmax, and ΔSUVmax*ΔSLD were predictive in univariate analyses. However, in the multivariate analysis, only IPI and ΔSUVmax remained independent predictors of PFS and OS. Conclusions Interim PET/CT may help to identify DLBCL patients with different prognoses. ΔSUVmax analysis shows the best accuracy and the strongest predictive value among these three methods. ΔSUVmax*ΔSLD may be a promising parameter to interpret iPET/CT images, reflecting both the changes in tumor size and metabolic activity.

Interim PET Evaluation in Diffuse Large B-Cell Lymphoma Using Published Recommendations: Comparison of the Deauville 5-Point Scale and the ΔSUVmax Method

“…This approach compares SUV max at baseline and interim PET staging. An unfavorable iPET result is defined as relative SUV max reduction of less than or equal to 66% -a cut-off that has been confirmed in several studies (3,(8)(9)(10). Advantages of the Deauville score are that it is easy to apply and only requires the iPET scan.…”

“…Despite their competing nature, little work on a direct comparison of the two methods is available in the literature (9,10,12). The Positron Emission Tomography-guided Therapy of Aggressive non-Hodgkin Lymphomas (PETAL) trial has recently shown that iPET response predicts outcome when assessed using the ΔSUV max approach.…”

<p>Statistical Challenges in Development of Prognostic Models in Diffuse Large B-Cell Lymphoma: Comparison Between Existing Models – A Systematic Review</p>

“…68 To determine the optimal cut-off point for continuous measurements for predicting OS, 11 of 46 studies used the ROC curve, which maximizes the likelihood ratio. 15,35,37,[40][41][42][43][44][45][46][47] The ROC curve analysis has earned a place in biomedical studies when interpreting the results of diagnostic accuracy of a continuous marker. The performance of a marker is evaluated by the area under the ROC curve (AUC), an indicator of overall "accuracy", in which a higher AUC value indicates a better performance.…”

“…In 11 of 46 studies, the cut-off of a continuously distributed measurement for OS prediction was defined as the point at which the sensitivity plus the specificity were maximized in the ROC curves. 15,35,37,[40][41][42][43][44][45][46][47] One study each used ROC curves to select the best cut-off of beta-2 microglobulin (B2M), 40 C-reactive protein (CRP), 44 lymphocyte to monocyte ratio, 44 platelet to lymphocyte ratio (PLR), 45 tumor-infiltrating T-lymphocyteproportion and ratio between CD4-positive and CD8-positive T-lymphocytes, 48 age, 35 maximum standardized uptake value, 47 and ratio Deauville score. 46 In two studies, ROC was used to assess the albumin level, 35,44 and in two the absolute monocyte count and absolute lymphocyte count.…”

“…In six articles the ratio in 3-year OS between low-risk and highrisk groups was not applicable owing to the short follow-up of high-risk patients or there being no surviving patients at 36 months. 35,45,47,56,60,61 The difference in 3-year OS ranged from 18.9% 41 to 100% 56 with335 and 105 patients, respectively, being analyzed.…”