Treatment outcomes of unknown primary squamous cell carcinoma of the head and neck

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.