Mantle Cell Lymphoma Prognostic Index (MIPI) Score

Original MIPI explained

The mantle cell lymphoma prognostic index (MIPI) score provides malignancy outcome stratification based on five independent risk factors:

■ Age is considered prognostic factor as it increases the risk of adverse outcome.

■ LDH (lactic acid dehydrogenase) is a marker of cellular damage (higher than normal values) that is used in the diagnosis of lymphoma, anemia, liver and lung disease.

■ ECOG performance status is a functional assessment of cancer patients established by the Eastern Cooperative Oncology Group.

■ White blood cells or leukocyte count is measured in 10⁹ cells/L, 10³ cells/microliter or 10³ cells/μL.

■ Ki67 is the cellular marker protein associated with cell proliferation. This is presented in percentage (when available, this is used in MIPIb).

MIPI formula = [0.03535 × Age (years)] + 0.6978 (if ECOG 2-4) + [1.367 × log10(LDH/ULN)] + [0.9393 × log10(WBC)].

Where:

ULN = LDH Upper Limit Normal.

WBC = White Blood Cell Count per microliter (x10⁶).

The below table associates the three MIPI score ranges with the low, intermediate and high risk groups.

Simplified MIPI

The simplified version is aimed for rapid calculation and awards a number of points to the value of the parameter.

Subsequent studies have proved that not only sMIPI has a similar prognostic performance to that of MIPI.

The table below presents the intervals for the parameters used and their correlated number of points:

There are three risk categories for the simplified version as well:

■ Low risk – scores of 0 to 3;

■ Intermediate risk – scores of 4 and 5;

■ High risk – scores of 6 to 11.

MIPIb (biological)

Where available, the Ki67 protein can also be considered in the calculation, to provide the MIPIb score. The Ki67 was found to be revelant for prognosis with a κ = 0.79 concordance.

MIPIb formula = [0.03535 × Age (years)] + 0.6978 (if ECOG 2-4) + [1.367 × log10(LDH/ULN)] + [0.9393 × log10(WBC)] + [0.02142 x Ki-67 (%)].

The MIPIb score classifies patients in three risk groups, as follows:

About the study

The MIPI was created by Hoster et al. as a specific malignancy risk stratification method for patients with mantle cell lymphoma as the other established prognostic tools (the International Prognostic Index or Follicular Lymphoma International Prognostic Index) only address diffuse large cell and follicular lymphoma cases

The study conducted in 2008 involved 455 advanced stage MCL patients treated within 3 clinical trials and resulted in the development of a new prognostic index of overall survival.

The score classified patient in low risk (44% of patients, median OS not reached), intermediate risk (35%, 51 months), and high risk groups (21%, 29 months).

The original prognostic factors were age, performance status, lactate dehydrogenase (LDH), and leukocyte count. Ki67 (cell proliferation factor) was explored as biological marker.

Original source

Hoster E, Dreyling M, Klapper W, Gisselbrecht C, van Hoof A, Kluin-Nelemans HC, Pfreundschuh M, Reiser M, Metzner B, Einsele H, Peter N, Jung W, Wörmann B, Ludwig WD, Dührsen U, Eimermacher H, Wandt H, Hasford J, Hiddemann W, Unterhalt M; German Low Grade Lymphoma Study Group (GLSG); European Mantle Cell Lymphoma Network. A new prognostic index (MIPI) for patients with advanced-stage mantle cell lymphoma. Blood. 2008; 111(2):558-65.

Other references

1. Hoster E, Klapper W, Hermine O, Kluin-Nelemans HC, Walewski J, van Hoof A, Trneny M, Geisler CH, Di Raimondo F, Szymczyk M, Stilgenbauer S, Thieblemont C, Hallek M, Forstpointner R, Pott C, Ribrag V, Doorduijn J, Hiddemann W, Dreyling MH, Unterhalt M. Confirmation of the mantle-cell lymphoma International Prognostic Index in randomized trials of the European Mantle-Cell Lymphoma Network. J Clin Oncol. 2014; 32(13):1338-46.

2. Lim SY, Horsman JM, Hancock BW. The Mantle Cell Lymphoma International Prognostic Index: Does it work in routine practice? Oncol Lett. 2010; 1(1): 187–188.