Cutaneous appendageal carcinoma incidence and survival patterns in the United States: a population-based study.

OBJECTIVE: To examine incidence patterns of patients diagnosed as having cutaneous appendageal carcinoma (CAC).

DESIGN: Population-based study using the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute data from 1978 through 2005.

PARTICIPANTS: A total of 1801 subjects from SEER 16 registries (2001-2005) for incidence analyses, 2228 from SEER 9 registries (1987-2005) for trend analysis, and 1984 subjects (1992-2004) for survival analysis.

MAIN OUTCOME MEASURE: Incidence rates (IRs) per 1 million person-years according to anatomic site, race, sex, age, and histologic type.

RESULTS: Cutaneous appendageal carcinomas are uncommon (age-adjusted IR, 5.1 per 1 million person-years), with the IR among men statistically significantly higher than women (6.3 vs 4.2, respectively; male to female IR ratio 1.51; P < .001). Hispanic whites (IR, 3.7), blacks (IR, 3.5), and Asian/Pacific Islanders (IR, 2.5) all had significantly lower IRs than non-Hispanic whites (IR, 5.7) (P < .001). Apocrine-eccrine carcinoma overall was the most common category (IR, 2.6), and the IR was highest among non-Hispanic white (IR, 2.8) compared with other ethnic/racial groups (P < .001). Cutaneous appendageal carcinomas IRs rose 100-fold with age, from 0.37 among those aged 20 to 29 years to 37.3 among those 80 years or older. From 1978-1982 to 2002-2005, the CAC IRs increased 150%, from 2.0 to 5.0; the apocrine-eccrine carcinoma and the sebaceous carcinoma IRs rose 170%, from 1.0 to 2.7, and 217%, from 0.6 to 1.9, respectively. Five-year relative survival rates overall were 99% for localized and 43% for distant disease.

CONCLUSIONS: Cutaneous appendageal carcinomas are rare tumors with IRs that vary by sex and racial/ethnic group. Cutaneous appendageal carcinoma IRs are increasing in the United States, especially for sebaceous carcinoma, perhaps related to improved recognition and classification, but factors such as UV exposure and immunosuppression may also play a role.