841P - Ki67-revised risk index to risk-stratify patients with extra-nodal natural killer/T cell lymphoma

Background

Although several clinical parameters-based prediction indexes of extra-nodal natural killer/T-cell lymphoma (ENKTL) are proposed, these indexes include none of pathological index and had insufficient accuracy. A superior clinically feasible prediction index for ENKTL in the modern chemotherapy era is warranted.

Methods

600 ENKTL patients receiving non-anthracycline based therapy from Sun Yat-sen University Cancer Center were subdivided into training and internal validation datasets. An external validation dataset included 191 patients from West China Hospital was enrolled. Ki67 proliferative index and 14 pretreatment clinical parameters were tested against overall survival (OS) and progression-free survival (PFS). A prediction model was constructed and validated.

Results

Factors independently associated with inferior OS were as follows: Ki67 ≥ 70%; age > 60 years; ECOG PS ≥ 2; B symptoms; stage-III/-IV disease and detectable EBV-DNA copy number. Each of these six factors contributed one point to a prediction model that stratified patients into four risk groups: 0-1 point, low-risk; 2 points, intermediate-risk;3 points, intermediate high-risk; 4-6 points, high-risk. In the training dataset, the 5-year OS rates were 91%, 75%, 65% and 26% for the low-, intermediate-, intermediate high- and high-risk group, respectively (P < 0.001). The 5-year PFS rates were 79%, 62%, 48% and 15%, respectively (P < 0001). The time-dependent area under the receiver-operator characteristic (AUROC) curve and Harrell’s C-statistic of Ki67-revised Risk Index (KRI) for OS and PFS prediction demonstrated a better performance than that of the international prognostic index (IPI), Korean prognostic index (KPI), prognostic index of natural killer lymphoma (PINK) and nomogram-revised risk index (NRI). Concordant results were successfully validated in both internal and external validation datasets.

Conclusions

KRI is a new promising prediction index to risk-stratify patients with ENKTL receiving non-anthracycline based therapy.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.