Background: Management of mycosis fungoides and Sézary syndrome (MF/SS) is complex, and randomized evidence to guide treatment is lacking. The institutional treatment volumes for MF/SS might vary widely nationally and influence patient survival.

Patients and methods: Using the National Cancer Database, we identified patients with a diagnosis of MF/SS from 2004 to 2011 in the United States who had received treatment at a reporting facility. The patients were grouped into quintiles according to their treatment facility's average annual treatment volume (ATV). The characteristics associated with ATV were identified and compared using χ² tests. Overall survival (OS) was compared among the ATV quintiles using the Kaplan-Meier method with log-rank tests and multivariable Cox regression with hazard ratios (HRs). OS was also analyzed using the annual patient volume as a continuous variable.

Results: A total of 2205 patients treated at 374 facilities were included for analysis. The ATV quintile cutoffs were 1, 3, 6, and 9 patients. With a median follow-up period of 59 months, the 5-year estimated OS survival increased with ATV from 56.7% in the lowest quintile (≤ 1 patient annually) to 83.8% in the highest quintile (> 9 patients annually; P < .001). On multivariable analysis, greater ATV was associated with improved survival when analyzed as a continuous variable (HR, 0.96 per patient per year; 95% confidence interval, 0.94-0.98; P < .001) and when comparing the highest quintile to the lowest quintile (HR, 0.46; 95% confidence interval, 0.39-0.55).

Conclusion: The present national database analysis demonstrated that higher facility ATV is associated with improved OS for patients with MF/SS. Further study is needed to determine the underlying reasons for improved survival with higher facility ATV.