Second Primary Head and Neck Cancer after Non-Head and Neck Index Cancers

Purpose:  The purpose of this study was to address the following clinical question: What is the incidence of second primary head and neck cancer among patients with an index cancer outside the head and neck and to determine what variables are associated with survival in this patient cohort?

Methods: The investigators implemented a retrospective cohort study from a sample of subjects diagnosed with head and neck cancer who were previously diagnosed with a cancer outside the head and neck region. The primary predictor variable was a diagnosis of cancer outside the head and neck. The primary outcome variable was diagnosis of a head and neck cancer. Secondary variables were patient age at diagnosis, gender, tobacco use, stage of second primary head and neck cancer, and treatment rendered. Chi square analysis was completed for categorical data, ANOVA was utilized to assess treatment effect and stage, and a 2-tailed independent samples t-test for age. P-values less than 0.05 were considered statistically significant. 

Results: There were 19,406 total cancers diagnosed at the University of Tennessee Cancer Center during the study period.  Of the 849 head and neck squamous cell carcinoma (HNSCC) cases, 40 (0.2%) were included in the study cohort.  The most common location for a second primary HNSCC was the gingiva (27.5%), followed by the oral tongue (17.5%). 68% of all second primary HNSCC were located in the oral cavity. The most common non-head and neck index cancer was prostate (27.5%) followed by breast (25%). Average duration of survival from the date of second primary diagnosis was 32.7 months (range 1-106 months).  There was no significant effect of age, tobacco use, sex, and TNM stage or treatment protocol on survival.  In patients with an index cancer of the head and neck, the most common location was oral tongue (33%).

Conclusion:  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 is in the gingiva and the most common primary cancer is located in the prostate. Health care professionals should remain diligent in their follow up of patients previously treated for cancer due to their risk of developing second primary cancers.

References:

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2)Chowdhry A, McHugh C, Fung C, Dhakal S, Constine L, Milano M. Second primary head and neck cancer after Hodgkin lymphoma: a population-based study of 44,879 survivors of Hodgkin lymphoma. Cancer. 2015 May 1;121(9):1436-45.