Construction and Validation of a Novel Nomogram for Predicting the Recurrence of Diffuse Large B Cell Lymphoma Treated with R-CHOP

Abstract

Purpose: To explore recurrence-risk factors of diffuse large B cell lymphoma (DLBCL) and construct a risk nomogram for predicting recurrence.

Patients and methods: A retrospective analysis was performed on 228 DLBCL patients who achieved complete remission after R-CHOP treatment between January 2015 and December 2019. Univariate and multivariate analyses were applied to identify recurrence-related risk factors from the pretreatment evaluation factors covering patients' demographic characteristics, clinical manifestations, serological indicators, pathological and immunohistochemical results. A nomogram was developed based on the above results and validated by the concordance index (C-index), the receiver operating characteristic (ROC) curve, and the calibration curve.

Results: The training and validation cohorts consisted of 160 and 68 patients (randomized by 7:3). Of the whole cohort, 50 of 228 (21.9%) cases recurred during follow-up. Three recurrence-risk factors including BCL2 expression (P = 0.027), CD10 expression (P = 0.021), LDH level (P = 0.004) were identified from multivariate analysis and entered the final nomogram. The C-index of the nomogram was 0.815 in training cohort and 0.797 in the validation cohort, higher than that of IPI system (0.699) and NCCN-IPI system (0.709). And the 1-year, 2-year, 3-year, and 4-year areas under ROC (AUC) were 0.812, 0.850, 0.837, and 0.801, respectively. The calibration curves also showed a good discrimination capability and accuracy.

Conclusion: The novel nomogram incorporating the three independent risk factors (BCL2 expression, CD10 expression and LDH level) provided a valuable tool for predicting DLBCL recurrence.

Keywords: DLBCL; diffuse large B cell lymphoma; nomogram; recurrence; risk factors.

Figure 1

Patient selection.

Figure 2

The novel nomogram incorporating LDH level with BCL2 expression and CD10 expression for DLBCL. A DLBCL patient with positive BCL2 expression, negative CD expression, elevated LDH level (1–3× ULN) or elevated LDH level (>3× ULN) could obtain 40 points, 61 points, 47 points and 100 points, respectively.

Figure 3

The calibration plots of nomogram in training cohort (A) and validation cohort (B) showed the predicted RFS rate on the x axis and the observed RFS on the y axis.

Figure 4

The predictive effectiveness of the novel nomogram, IPI system and NCCN-IPI system. (A) The 1-year, 2-year, 3-year and 4-year AUC of the novel nomogram was 0.812, 0.85, 0.837, and 0.801, respectively. (B) The 1-year, 2-year, 3-year and 4-year AUC of IPI system was 0.714, 0.74, 0.719, and 0.66, respectively. (C) The 1-year, 2-year, 3-year and 4-year AUC of NCCN-IPI system was 0.688, 0.757, 0.722, and 0.695, respectively.