Head and Neck Sweat Gland Carcinomas: Clinical Characteristics and Patterns of Care

Abstract

<h3>Purpose/Objective(s)</h3> Little is known about head and neck malignancies originating from cutaneous adnexal tissue. Using the National Cancer Database (NCDB), we attempted to characterize patients with malignant sweat gland carcinomas of the head and neck region. <h3>Materials/Methods</h3> Adult patients with malignant head and neck sweat gland carcinomas diagnosed between 2004-2018 in the NCDB were selected. Demographics, comorbidities, tumor characteristics, and treatments were analyzed. Patients with unknown survival outcomes, no surgical treatment, less than six months of follow-up, previous malignancies, or T0 tumors were excluded from survival analysis. Kaplan-Meier analysis was used to assess overall survival at three and five years. Cox proportional-hazards regression was used to assess for predictors of overall survival. <h3>Results</h3> We identified 2723 patients with sweat gland carcinomas in the NCDB. The median age was 68 years (range: 20-90), and 1366 patients (50.2%) were female. The most common histology was microcystic adnexal carcinoma (676, 24.8%) followed by mucinous carcinoma (535, 19.6%) and porocarcinoma (419, 15.4%). Of patients with complete staging information, most were staged as T1 (916, 63.0%), N0 (1871, 97.2%), and M0 (2278, 99.3%). Nodal metastases were present in 94 patients (10.1%). The highest rates of nodal disease were observed in apocrine adenocarcinoma (29.0%), squamoid eccrine ductal carcinoma (17.5%), and porocarcinoma (16.6%). Excluding these histologies, the nodal metastasis rate was 6.5%. 2559 patients (95.4%) were treated with surgery. Of these, 334 (12.9%) received adjuvant radiation and 29 (1.1%) received chemoradiation. Three-year and five-year overall survival rates were 88.1% (95% CI: 86.5%-89.6%) and 80.3% (78.3%-82.4%), respectively. On univariable analysis, age, male gender, white race, comorbidities, treatment at a community hospital, tumor size >1cm, T and N stage, lymphovascular invasion, and positive margins were associated with worse survival. Age, male gender, comorbidities, size >1cm, and nodal stage retained their significance in multivariable analysis. <h3>Conclusion</h3> Sweat gland carcinomas are a diverse group of rare malignancies. While the rate of nodal metastases is low, certain histologies harbor higher potential for lymph node metastases with worse survival. Tumor size larger than 1cm is also associated with worse survival. The above data could help clinicians in the management of these rare tumors.