Changing incidence trends of cutaneous T-cell lymphoma.

IMPORTANCE: Cutaneous T-cell lymphoma (CTCL) incidence and survival have been increasing steadily for over 25 years.

OBJECTIVE: We sought to measure changes in CTCL incidence trends and survival rates.

DESIGN, SETTING, AND PARTICIPANTS: Population-based study. The CTCL incidence and survival data were obtained from the 9 original registries (1973-2009) and the 4 additional registries (1992-2009) of the Surveillance, Epidemiology and End Results (SEER) program of the National Cancer Institute (NCI). Trend analysis was performed using the Joinpoint Regression Program provided by the NCI. Survival analysis was performed using the SeerSTAT statistical software of the NCI. The total number of cases of CTCL from 1973 to 2009 was 6230.

MAIN OUTCOMES AND MEASURES: Diagnoses of CTCL.

RESULTS: Overall CTCL incidence has stabilized since 1998 (95% CI, 1994-2002), with an annual percent change (APC) of 5.7% from 1973 to 1998 (95% CI, 4.9%-6.5%) and an APC of 0.1% from 1998 to 2009 (95% CI, -1.4% to 1.5%). Similar incidence stabilization patterns were found in subgroup analyses of race, sex, age, diagnosis, and registry. Five-year CTCL survival rates increased until 2004.

CONCLUSIONS AND RELEVANCE: The incidence of CTCL is no longer increasing. Causes for this trend change may include real incidence stabilization, stabilization of physician detection, or artifact.