Outcomes after diagnosis of mycosis fungoides and Sézary syndrome before 30 years of age: a population-based study.
OBJECTIVE
Mycosis fungoides and Sézary syndrome (MF/SS) are rare in children and young adults, and thus the incidence and outcomes in this patient population are not well studied.


OBJECTIVE
To assess the incidence and outcomes of MF/SS in patients diagnosed before 30 years of age.


METHODS
Retrospective study of 2 population-based cancer registries-the California Cancer Registry (n = 204) and 9 US cancer registries of the Surveillance, Epidemiology, and End Results program (SEER 9; n = 195)-for patients diagnosed with MF/SS before 30 years of age.


METHODS
Overall survival was calculated by the Kaplan-Meier method. The risk of a second cancer was assessed by calculating the standard incidence ratio (SIR) comparing observed cancer incidence in patients with MF/SS with the expected incidence in the age-, sex-, and race-standardized general population.


RESULTS
The incidence of MF/SS is rare before 30 years of age, with an incidence rate of 0.05 per 100,000 persons per year before age 20 years and 0.12 per 100,000 persons per year between ages 20 and 29 years in the California Cancer Registry. At 10 years, patients with MF/SS had an overall survival of 94.3% (95% CI, 89.6%-97.2%) in the California Cancer Registry and 88.9% (95% CI, 82.4%-93.2%) in SEER 9. In SEER 9, there was a significant excess risk of all types of second cancers combined (SIR, 3.40; 95% CI, 1.55-6.45), particularly lymphoma (SIR, 12.86; 95% CI, 2.65-37.59) and melanoma (SIR, 9.31; 95% CI, 8.75-33.62). In the California Cancer Registry, the SIR for risk of all types of second cancers was similar to that in SEER 9 (SIR, 3.45; 95% CI, 0.94-8.83), although not statistically significant.


CONCLUSIONS
Young patients with MF/SS have a favorable outcome, despite a strong suggestion of an increased risk of second primary cancers. Prolonged follow-up is warranted to definitively assess their risk of developing second cancers in a lifetime.
Division of Hematology and Oncology, Department of Medicine, University of California, San Francisco.
Weiyun Z
WZ
Ai
Cancer Prevention Institute of California, Fremont3Division of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California.
Theresa H
TH
Keegan
Cancer Prevention Institute of California, Fremont.
David J
DJ
Press
Cancer Prevention Institute of California, Fremont.
Juan
J
Yang
Departments of Pathology and Dermatology, University of California, San Francisco.
Laura B
LB
Pincus
Department of Dermatology, Stanford University School of Medicine, Stanford, California.
Youn H
YH
Kim
Division of Epidemiology, Department of Health Research and Policy, Stanford University School of Medicine, Stanford, California6Health Sciences, Exponent, Inc, Menlo Park, California.
Ellen T
ET
Chang
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D007223:Infant; D053208:Kaplan-Meier Estimate; D008223:Lymphoma / Q000453:epidemiology*; D008297:Male; D008545:Melanoma / Q000453:epidemiology*; D008875:Middle Aged; D009182:Mycosis Fungoides / Q000175:diagnosis / Q000453:epidemiology*; D016609:Neoplasms, Second Primary / Q000453:epidemiology*; D012189:Retrospective Studies; D018426:SEER Program; D012751:Sezary Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D015996:Survival Rate; D014481:United States / Q000453:epidemiology; D055815:Young Adult