Objectives: To study and update the clinical characteristics and long-term outcome of our patients with mycosis fungoides (MF) and Sézary syndrome (SS), and to identify important clinical factors predictive of survival and disease progression.

Design: A single-center, retrospective cohort analysis.

Setting: Academic referral center for cutaneous lymphoma.

Patients: Five hundred twenty-five patients with MF and SS evaluated and managed at Stanford University Cutaneous Lymphoma Clinic, Stanford, Calif, from 1958 through 1999.

Main outcome measures: We calculated long-term actuarial overall and disease-specific survivals and disease progression by the Kaplan-Meier method, and relative risk (RR) for survival calculated from expected survivals in control populations.

Results: The majority of our patients presented with T1 (30%) or T2 (37%) disease; 18% presented with T3 and 15% with T4 skin involvement. Forty-three percent of deaths were attributable to MF, primarily in patients with T3 or T4 disease. The patients with a more advanced T classification and clinical stage had a worse survival outcome. Except for patients with T1 or stage IA disease, the RR for death is greater in patients with MF than in a control population (RR, 2.2 in stage IB/IIA disease, 3.9 in stage IIB/III disease, and 12.8 in stage IV disease). Despite similar overall survival in patients with stage IB or IIA disease, their disease-specific survivals were significantly different (P =.006). The most significant clinical prognostic factors in the univariate analysis were patient age, TNM and B classifications, overall clinical stage groupings, and the presence or absence of extracutaneous disease. In the multivariate analysis, patient age, T classification, and the presence of extracutaneous disease were the most important independent factors. The risk for disease progression to a more advanced TNM or B classification, worse clinical stage, or death due to MF correlated with the severity of the initial T classification. The risk for development of extracutaneous disease also correlated with T classification; none of these patients had T1 disease when their extracutaneous disease was detected.

Conclusions: Patients with MF and SS have varying risks for disease progression or death. The most important clinical predictive factors for survival include patient age, T classification, and the presence of extracutaneous disease. The significant disease-specific survival differences between different clinical stages validate the usefulness of the present MF clinical staging system of the National Cancer Institute.