China: Findings from a Retrospective Cohort Study of Patients with Mycosis Fungoides

Findings from a retrospective cohort study of patients with mycosis fungoides (MF) in China suggest that Asian patients may be diagnosed at an earlier age and have better survival outcomes than White patients, a difference that can impact future patient treatment strategies. The findings were published online in the JAMA Dermatology journal on August 16, 2023.

Mycosis fungoides is the most common type of cutaneous T-cell lymphoma (CTCL) that accounts for about 50% of all primary cutaneous lymphomas. In recent years, an increase in MF incidence has been observed. As an indolent disease, the majority of MF patients are diagnosed at an early stage, with characteristics of slow progression over years, and a favourable prognosis. However, 9% to 34% of patients progress to advanced stages which is tied to increased mortality.

Understanding MF's survival statistics and prognostic factors will assist in improved MF management by identifying patients at high risk of disease progression and its associated mortality. But prognostic statistics and data available on survival outcomes for mycosis fungoides patients in Asia are limited.

To fill this knowledge gap, Zhuojing Chen, Peking University First Hospital, Beijing, China, and colleagues aimed to determine the survival outcomes and prognostic factors of patients with mycosis fungoides in a cohort in China in a retrospective cohort study.

The study included 461 MF patients (median age at diagnosis 46 years, 59.7% were men; all 461 were Chinese) who received treatment at a tertiary referral centre for skin lymphoma from 2009 to 2021. The study's main outcomes and measures included progression-free survival (PFS), disease-specific survival (DSS), and overall survival (OS). Adjusted HRs (aHRs) and hazard ratios (HRs) were determined for prognostic factors after adjusting for sex, age, and overall TNMB [tumour, node, metastasis, blood] stage.

Study Findings

• 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
  • 23.6% for IV
• Compared with a UK cohort, the Chinese cohort had a younger median age at diagnosis (46 years vs 54 years) and a more favourable 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, 2.25; 2.09; 2.27)
  • Advanced TNMB stage
  • Advanced overall stage
  • Large-cell transformation (aHR, 2.16; 2.29; 2.21)
  • Elevated lactate dehydrogenase levels (aHR, 3.92; 4.77; 5.05)
• Biological sex and plaque lesion type were not associated with prognosis among this study cohort.

"The findings of the study of patients with MF in China suggest that Asian patients are diagnosed at a younger age and have a higher 5-year overall survival versus patients of other races in studies in other countries (predominantly White)," the researchers wrote. "Prognostic factors were similar to those of previous studies, except for plaque lesion type and patients."

"There is a need for larger, multicenter studies to further understand prognostic factors and survival outcomes among Asian patients with mycosis fungoides," they concluded.

Reference

Chen Z, Lin Y, Qin Y, et al. Prognostic Factors and Survival Outcomes Among Patients With Mycosis Fungoides in China: A 12-Year Review. JAMA Dermatol. Published online August 16, 2023. doi:10.1001/jamadermatol.2023.2634