Clinically assessed mycosis fungoides tumor burden index as a prognostic marker in tumor-stage mycosis fungoides: a retrospective cohort study

Prognostic markers are needed for tumor-stage mycosis fungoides (MF) because of their variable prognosis. The objectives of this study were to explore prognostic markers for tumor-stage MF and assess the prognostic significance of clinically assessed MF tumor burden index (MTBI). MTBI was devised to consider the tumor size ≥ 2 cm, number ≥ 5, ulcers, and body surface area ≥ 50%. The prognostic value of MTBI and other potential markers derived from blood tests and skin biopsy were evaluated retrospectively using a tertiary medical center database. We included 38 cases of tumor-stage MF. The mean age was 52.1 years, and the male-to-female ratio was 2.5:1. In multivariable analysis, MTBI ≥ 3 (adjusted hazard ratio, 9.41; 95% confidence interval, 1.13–78.15) was significantly associated with worse disease-specific survival. Ulcers were the only MTBI constituent significantly associated with survival. Among other markers, elevated lactate dehydrogenase level was associated with a worse disease-specific survival. Neutrophil-lymphocyte-ratio, pan-inflammation-value, CD30 positivity, Ki-67 index, large cell transformation, and monoclonal T-cell receptor gene rearrangement were not associated with prognosis. In conclusion, MTBI is useful and promising prognostic marker for tumor-stage MF.