Second Primary Head and Neck Cancers After Non-Head and Neck Primary Cancers

The purpose of the present study was to determine the rate of second primary head and neck cancer development among patients with a primary cancer diagnosed outside the head and neck region, to present the clinical characteristics of this population, and to determine whether any variables are associated with survival.

We designed a case series based on a sample of patients diagnosed with head and neck cancer who had previously been diagnosed with cancer located outside the head and neck region. The primary predictor variable was a diagnosis of cancer outside the head and neck region. The primary outcome variable was the diagnosis of a second cancer in the head and neck region. χ² Goodness-of-fit tests were used to test for differences between the observed and expected rates.

A total of 19,406 cancers were diagnosed at the University of Tennessee Cancer Institute during the study period from July 1, 2004 to June 30, 2014. The rate of second primary head and neck cancer among patients with a non-head and neck primary cancer was 0.2%. These 40 cancers occurred among a total of 849 head and neck squamous cell carcinoma (HNSCC) cases (5%) diagnosed during the study period. The most common location for a second primary HNSCC was the gingiva (27.5%), followed by the oral tongue (17.5%). Significantly more gingival cancers were diagnosed than expected (P < .001) and significantly fewer tongue cancers than expected (P = .01). The most common primary cancer was prostate (27.5%), followed by breast (25%). The median survival was 28.5 months after the second primary diagnosis. A nonsignificant effect was found for age (P = .30), tobacco use (P = .12), gender (P = .60), TNM stage (P = .29), and treatment protocol (P = .96) on survival.

The development of a second primary HNSCC in a population of patients with non-head and neck primary cancers is associated with decreased overall survival. The most common presentation of a second primary HNSCC in our study was in the gingiva and the most common primary cancer was in the prostate. Clinicians should consider the increased proportion of gingival cancers in this population when examining patients and be aware of the decrease in overall survival.