Patterns of Care and Outcomes by Treatment Era in Mycosis Fungoides

Abstract

Mycosis Fungoides (MF) and Sezary syndrome (SS) are rare T-cell lymphomas, with an estimated incidence of 6 per million persons. Real world evidence on patients, treatment practices, and outcomes are limited. We examined practice patterns and overall survival (OS) outcomes in a nationwide cohort of patients with MF and SS.Patients diagnosed with MF and SS between 2004 and 2016 were identified in the National Cancer Database. Patients were excluded if disease staging or management were incomplete in the database. Pearson's chi-squared test and multivariate logistic regression analyses were used to assess patterns of care and the distribution of demographic, clinical, and treatment factors for treatment modalities as well as treatment eras. Kaplan Meier analyses and doubly-robust estimation with multivariate Cox proportional hazards modeling were used to compare OS by stage and by treatment era. Treatment eras were defined as 2004-2010 and 2011-2016 due to the evolution of immunotherapy options around that time point.W We identified 9,462 patients with MF or SS. Of these 3,570 were excluded due to incomplete or discordant data. Among the remaining 5,892 patients, 1,779 (30%) were treated with chemotherapy (CMT), 853 (14%) were treated with radiotherapy (RT) and 384 (7%) were treated with immunotherapy (IT). Factors associated with the receipt of CMT included living greater than 50 miles from care and stage III or IV disease. CMT was less frequently utilized in females, patients in the Middle Atlantic (NJ, NY, PA), East North Central (IL, IN, MI, OH, WI) and Pacific (AK, CA, HI, OR, WA) regions and patients treated from 2011-2016. Factors associated with the use of RT included stage I or II disease, Medicare insurance status, and receipt of IT. RT was used less commonly in academic centers, in the Middle-Atlantic, West-North Central (IA, KS, MN, MO, ND, NE, SD), and Pacific regions as well as in females and black patients. IT use was associated with living 50-200 miles from care, receipt of RT, and stage III or IV disease. It was less common in the Pacific and West-North Central regions and in those treated from 2011-2016. Comparing OS outcomes across eras, 2004-2010 vs 2011-2016, there was no difference in outcome among patients with stage I or II disease after propensity score matching (HR 0.97 P = 0.67 95% CI 0.84-1.12). However, amongst patients with stage III or IV disease, OS was significantly improved in the cohort treated from 2011-20016 (HR 0.70, P = 0.015, 95% CI 0.53-0.93).This study comprises the largest retrospective database analysis of patterns of care in patients with MF/SS. Multiple factors were identified that were predictive of utilization of CMT, RT, and IT as treatment for the disease. Disease stage was found to be well correlated with OS. Importantly, OS outcomes in patients with stage III and IV disease have improved in recent years.