Is it possible to improve prognostic value of NCCN-IPI in patients with diffuse large B cell lymphoma? The prognostic significance of comorbidities

The prognostic value of the International Prognostic Index (IPI) has been re-evaluated in the rituximab-treated diffuse large B cell lymphoma (DLBCL) patients. Accordingly, National Comprehensive Cancer Network-IPI (NCCN-IPI) has been introduced to estimate prognosis of DLBCL patients. However, comorbidities that frequently affect elderly DLBCL patients were not analyzed. The aim of this study was to evaluate the prognostic significance of comorbidities using Charlson Comorbidity Index (CCI) in 962 DLBCL patients. According to CCI, majority of patients (73.6%) did not have any comorbidity, while high CCI (≥ 2) was observed in 71/962 (7.4%) patients, and in 55/426 (12.9%) of the elderly patients aged ≥ 60 years. When the CCI was analyzed in a multivariate model along with the NCCN-IPI parameters, it stood out as a threefold independent risk factor of a lethal outcome. Also, we have developed a novel comorbidity-NCCN-IPI (cNCCN-IPI) by adding additional 3 points if the patient had a CCI ≥ 2. Four risk groups emerged with the following patient distribution in low, low-intermediate, high-intermediate, and high group: 3.4, 34.3, 49.4, and 12.5%, respectively. The prognostic value of the new cNCCN-IPI was 2.1% improved compared to that of the IPI, and 1.3% improved compared to that of the NCCN-IPI (p < 0.05). This difference was more pronounced in elderly patients, in whom the cNCCN-IPI showed a 5.1% better discriminative power compared to that of the IPI, and 3.6% better compared to the NCCN-IPI. The NCCN-IPI enhanced by the CCI and combined with redistributed risk groups is better for differentiating risk categories in unselected DLBCL patients, especially in the elderly.