Tumor burden index as a prognostic tool for cutaneous T-cell lymphoma: a new concept

To introduce a prognostic tool for cutaneous T-cell lymphoma that takes into account the tumor burden and to compare the prognostic value of this tumor burden index (TBI) with that of other prognostic factors.

Retrospective clinical and statistical study.

One hundred sixteen patients with cutaneous T-cell lymphoma.

A TBI was designed that takes into account the types, numbers, and severity of skin lesions with the use of the Cox proportional hazard model.

Models of the TBI were developed to test the relative contributions of patches, plaques, and tumors to the total tumor burden and, hence, survival time. Weighting factors reflecting the severity of each skin lesion were tested and incorporated. The best prognostic correlation was a dichotomized index with the following formula: TBI = 1 + (patches x 2) + (plaques x 2) + (tumor x 1.3), where the patches factor equals 0 if 30% or less of the skin area is involved and 1 if greater than 30% of the skin area is involved and where the plaque or tumor factor equals 1 if plaques or tumors are present. Both the TBI and TNM provided predictive information. Discrimination of survival curves and significance of differences was better for TBI (P < .001) than for TNM (P = .009). Sex was also statistically related to survival (males had a better prognosis; P < .04), whereas neither age at first symptoms (P = .35) nor age at time of diagnosis (P = .36) was of prognostic value.

The TBI offers a simple prognostic index for the evaluation of cutaneous T-cell lymphoma. It may become a valuable tool for designing therapeutic strategies for patients according to their specific survival expectancies. However, this model is preliminary and has to be validated on a larger number of patients.