Objectives: To determine the disease course of Dutch patients with mycosis fungoides and to define factors related to disease progression and survival.
Design: A multicenter, 13-year, retrospective cohort analysis.
Setting: Eight dermatology departments collaborating in the Dutch Cutaneous Lymphoma Group.
Patients: Three hundred nine patients with mycosis fungoides registered between October 1985 and May 1997, including 89 patients with limited patches or plaques (stage Ia), 135 with generalized patches or plaques (stage Ib), 46 with skin tumors (stage Ic), 18 with enlarged but uninvolved lymph nodes (stage II), 18 with lymph node involvement (stage III), and 3 with visceral involvement (stage IV).
Main outcome measures: Response to initial treatment, sustained complete remission, actuarial disease progression, and overall and disease-specific survival per clinical stage.
Results: The median follow-up was 62 months (range, 1-113 months). For the entire group, the actuarial overall and disease-specific survival was 80% and 89% at 5 years, and 57% and 75% at 10 years, respectively. The actuarial 5-year disease-specific survival of patients with stage Ia, Ib, and Ic disease was 100%, 96%, and 80%, respectively, and only 40% for patients with stage III disease. Using multivariate analysis, the presence of extracutaneous disease, the type and extent of skin involvement, the response to initial treatment, and the presence of follicular mucinosis were independently associated with higher disease progression and mortality rates. The calculated risks of disease progression at 5 and 10 years gradually increased from 4% to 10% for those with stage Ia disease, from 21% to 39% for those with stage Ib disease, and from 32% to 60% for those with stage Ic disease; for those with stage III disease, the risk remained at 70% at 5 and 10 years. The overall risk of disease progression at 5 and 10 years was 24% and 38%, respectively, for the total study group.
Conclusion: At least within the first 10 years after diagnosis, disease progression and mycosis fungoides-related mortality occur in only a subset of patients generally presenting with advanced disease.