Evaluation of the Mantle Cell Lymphoma International Prognostic Index (MIPI) as An Indicator of Overall Survival, Progression Free Survival, Survival From Relapse

Prognosis for survival in mantle cell lymphoma (MCL) has recently been characterized using the MIPI algorithm. Using a retrospectively generated dataset of 150 patients with MCL seen at the H Lee Moffitt Cancer Center we sought to validate this approach in a more heterogeneous population.

Patients were identified by physician survey, and through the use of our pathology and Total Cancer Care databases. Retrospective analysis was conducted with approval of our Institutional Review Board. In total 150 patients with MCL were identified, among whom MIPI data was available for 85 patients with a median followup of 36.8 months. Survival (expressed in months) was verified using our institutional records and the Social Security Death Index. Exploratory analysis of progression (n=79) and survival from the time of relapse (n=43) as stratified by MIPI were also conducted among evaluable patients. Data were compared using Kaplan-Meier survival analyses.

Median age was 65y (range 31–87), 73% male, 3% ECOG >1, 88% stage III/IV disease, 36% with extranodal involvement, and 38% with splenomegaly. Evaluation of the entire cohort shows median OS 57 (95% CI: 48, 70.9), median PFS 21.8 (95% CI: 14.2, 25.6), and median survival after relapse 27.6 (95% CI 25.4, 30.8). No benefit in OS was observed among patients receiving Cytarabine (HR 1.04, p=0.91) and/or Rituximab (HR 1.31, p=0.61) with initial chemotherapy. Relationship between PFS and survival after relapse demonstrated rho=0.51 (p<.0001).

Among 85 evaluable patients 36% had elevated LDH, while 36% were MIPI-Low, 38% MIPI-Int, and 28% MIPI-High. Stratification by MIPI shows median OS of 30.4 (12.4, 42) for MIPI-High, 64.8 (53,-) for MIPI-Int, and has not been reached by MIPI-Low, with little separation between MIPI-Low and MIPI-Int groups before 60 months. PFS was 6.3 (3.7,15) for MIPI-High, 25.6 (16.5,31) for MIPI Int, and 26.5 (14,40.3) for MIPI-Low, with little separation between MIPI-Low and MIPI-Int groups before 30 months. Survival after relapse was 12.4 (9.1,25.4) for MIPI-High, 34.2 (27.6,-) for MIPI-Int, and was not reached for MIPI-Low, again with little separation between MIPI-Low and MIPI-Int groups before 30 months.

In our experience, the MIPI remains an effective tool for stratification of OS in MCL, however, extended followup is needed to realize such differences among those with MIPI-Low and MIPI-Int disease. The MIPI was similarly effective in predicting a poor PFS and survival from relapse among those with high risk disease, though was of less utility among MIPI-Low and MIPI-Int patients.

No relevant conflicts of interest to declare.