Synchronous and Metachronous Tumors in Head and Neck Cancer: Analysis of the SEER Database

Abstract

Objectives: 1) Describe the prevalence of synchronous and metachronous second primary tumors in head and neck cancer patients. 2) Determine the overall survival rate of patients with second primary tumors based on location of index tumor, number of accumulated tumors, and synchronicity or metachronicity. Methods: Population based study (1973 to 2008) using the Surveillance, Epidemiology, and End Results (SEER) database. Inclusion criteria were patients with non-esophageal mucosal head and neck squamous cell carcinoma (HNSCC) and no previous diagnosis of cancer. Synchronous tumors were defined as diagnosed within 6 months of identification of the index tumor, while metachronous tumors were diagnosed more than 6 months after the index tumor. Results: There were 58,363 HNSCC patients (M:F 42,794: 15,569) in the SEER database. Eleven percent (6,855) developed a second primary. The prevalence of head and neck and non-head and neck second primary tumors was 3.2% (1,885) and 8.5% (4,970), respectively. Of the 1,885 patients with a second primary in the head and neck, 32% (602) were synchronous, 68% (1,283) were metachronous. Of the 4,970 patients with a non-head and neck second primary, 21% (1056) were synchronous and 79% (3914) were metachronous. Overall survival was significantly worse in patients with second primary tumors and by total number of accumulated tumors (synchronous or metachronous; P = 0.045 and P < 0.001, respectively). Conclusions: The majority of patients with head and neck squamous cell carcinoma who developed synchronous or metachronous tumors are of non-head and neck origin. The development of multiple second neck primaries confers a worse prognosis.