Rare Tumors Through the Looking Glass: an Examination of Malignant Cutaneous Adnexal Tumors

Objective: To identify prognostic factors related to malignant cutaneous adnexal tumors.

Design: Population-based study using the Surveillance, Epidemiology, and End Results database from January 1, 1988, through December 31, 2006.

Setting: Seventeen population-based cancer registries.

Participants: A total of 4032 patients with malignant cutaneous adnexal tumors.

Main Outcome Measures: Overall survival (OS) and disease-specific survival (DSS).

Results: Ten-year OS and DSS rates were 54% and 97%, respectively. Unfavorable factors for OS were increasing age (hazard ratio [HR] 1.08; 95% confidence interval [CI], 1.07-1.09; P < .001), distant metastases (3.26; 2.34-4.53; P < .001), no surgical procedure (1.27; 1.01-1.59; P = .04), grade IV tumors (1.97; 1.18-3.28; P = .009), nodal metastases (2.19; 1.40-3.43; P = .001), and T3 tumors (1.37; 1.00-1.87; P = .04). Favorable factors for OS were a wide surgical excision (HR, 0.78; 95% CI, 0.68-0.89; P < .001), female sex (0.73; 0.65-0.82; P < .001), malignant eccrine spiradenoma (0.72; 0.53-0.99; P = .04), and histologic findings of sweat duct carcinoma (0.63; 0.44-0.90; P = .01). Unfavorable factors for DSS included N1 status (HR, 6.77; 95% CI, 2.11-21.68; P < .001), distant metastases (12.24; 6.03-24.85; P < .001), histologic findings of malignant eccrine spiradenoma (5.62; 1.25-25.34; P = .02), and no surgical procedure (2.81; 1.09-7.23; P = .03). Favorable factors for DSS included female sex (HR, 0.52; 95% CI, 0.30-0.91; P = .02).

Conclusions: Five-year survival among patients with malignant cutaneous adnexal tumors is good in the absence of distant metastases. Wide resection may be preferable to less aggressive excision. The prognostic importance of lymph node metastases warrants consideration of lymph node basin staging.