Prognostic Factors and Survival Outcomes Among Patients With Mycosis Fungoides in China

Importance There are limited prognostic statistics and data available on survival outcomes for patients with mycosis fungoides (MF) in Asia. Objective To determine the prognostic factors and survival outcomes of patients with MF among a cohort in China. Design, Setting, and Participants This was a retrospective cohort study of patients with MF who received treatment at a tertiary referral center for skin lymphoma (Peking University First Hospital, Beijing, China) from August 1, 2009, to August 31, 2021. Data were analyzed from September 1, 2021, to December 31, 2022. Main Outcomes and Measures Overall survival (OS), disease-specific survival (DSS), and progression-free survival (PFS); for prognostic factors, hazard ratios (HRs), and adjusted HRs (aHRs; adjusted for sex, age, and overall TNMB [tumor, node, metastasis, blood] stage) determined using the Cox proportional hazards model. Results The study cohort comprised 461 patients with MF (median [range] age at diagnosis, 46 [5-87] years; 275 [59.7%] men and 186 [40.3%] women; 461 [100%] Chinese). The overall 5-year rate was 82.2% for OS, 83.5% for DSS, and 79.6% for PFS. Stage-specific 5-year OS rates were 95.7% for stage IA, 93.2% for IB, 95.7% for IIA, 70.1% for IIB, 55.3% for III, and 23.6% for IV. Compared with a UK cohort, our Chinese cohort had a younger median age at diagnosis (46 years vs 54 years) and a more favorable 5-year OS (82.2% vs 75.0%); however, after adjusting for age, the discrepancy in the 5-year OS rate was diminished (77.3% vs 76.4%). Cox models revealed that unfavorable predictors of OS, PFS, and DSS, respectively, were: age older than 60 years (aHR [95% CI], 2.25 [1.28-3.96]; 2.09 [1.16-3.76]; 2.27 [1.39-3.72]); advanced TNMB stage; advanced overall stage; large-cell transformation (aHR [95% CI], 2.16 [1.17-3.99]; 2.29 [1.21-4.33]; 2.21 [1.26-3.86]); and elevated lactate dehydrogenase levels (aHR [95% CI], 3.92 [1.64-9.36]; 4.77 [1.86-12.22]; 5.05 [2.23-11.42]). Biological sex and plaque lesion type were not associated with prognosis among this study cohort. Conclusion and Relevance The findings of this retrospective cohort study of patients with MF in China suggest that Asian patients are diagnosed at a younger age and have a higher 5-year OS compared with patients of other races in studies in other countries (predominantly White). Prognostic factors were similar to those of previous studies, except for patient sex and plaque lesion type.