Background: Treatment modality of unknown primary squamous cell carcinoma of the head and neck (SCCHN) remains controversial.
Objectives: To evaluate the treatment outcomes and prognostic factors of unknown primary SCCHN.
Materials and methods: Patients with unknown primary SCCHN from April 1995 to March 2013 were recruited retrospectively.
Results: Sixty-nine patients were enrolled. The median time of follow-up was 55.5 months. The 2-year loco-regional control rate of all the patients was 60.4%. Multivariate Cox regression analysis revealed that N3 stage, extracapsular spread, distant metastasis, and treatment modality were significantly associated with neck recurrence. The actuarial 5-year disease-specific survival rates of neck dissection, neck dissection plus adjuvant therapy, radiotherapy alone, and combined therapy were 80.0%, 61.7%, 33.3%, and 68.8%, respectively (p = 0.046). The 5-year disease-specific survival rates of N1/N2a, N2b/N2c, and N3 stage were 83.9%, 64.3%, and 36.7%, respectively (p = 0.013). Univariate regression analysis revealed that neck recurrence, supraclavicular node involvement, distant metastasis, N3 stage, and unhealthy lifestyle habits were correlated with disease-specific mortality, especially the first three parameters. Patient's occupation and comorbidity were not significantly correlated with survival.
Conclusions: Composite therapy is mandatory for advanced unknown primary SCCHN. Supraclavicular node involvement and unhealthy lifestyle habits, such as betel nut chewing, indicate a poor prognosis.