Introduction

While head and neck cancer is relatively rare in the United States, it is a more significant entity in some parts of the developing world. In the United States, the vast majority of head and neck malignancies are squamous cell carcinomas of the UADT (ie, the oral cavity, the oro- and hypopharynx, and the larynx). Approximately 90% of HNSCCs occur after exposure to tobacco and/or alcohol. Emerging information suggests that one’s genetic background and exposures apart from tobacco and alcohol contribute to the risk of HNSCC as well. Ultimately, the public health goal is better prevention of these malignancies by reducing the use of tobacco and alcohol, discovering and avoiding other causative agents, and identifying the genetically susceptible. Such work will enhance both primary and secondary prevention efforts.

Descriptive Epidemiology

Incidence
In the United States, 19,400 new cases of oral cavity cancer, 8,300 new cases of pharyngeal cancer, and 9,500 new cases of laryngeal cancer will be diagnosed in 2003. Head and neck cancers account for approximately 3% of all new cancer cases in the United States annually, excluding basal and squamous cell carcinomas of the skin. The absolute incidence of oral cavity and pharyngeal cancer has been approximately 21,000 and 9,000 new cases, respectively, annually since 1985; however, the number of new cases of laryngeal cancer has steadily declined since 1993, when 12,600 new cases were diagnosed.

In the United States, approximately 1 in 3 oral cavity/pharyngeal cancers occur in women while only 1 in 5 laryngeal cancers occur in women. The incidence rates in men are double the rates in women for oral cavity/pharyngeal cancers and triple the rates in women for laryngeal cancer. Since the mid 1980s, incidence rates (age-adjusted to the 2000 US standard) for both oral cavity/pharyngeal cancer and laryngeal cancer have steadily declined in men to 15.2 of 100,000 and 6.9 of 100,000, respectively, in 1999. However, during the same time period these rates have been relatively stagnant in women. While black and white women have similar rates of oral cavity/pharyngeal cancer, black men have a 30% higher rate of oral cavity/pharyngeal cancer than white men. Both black men and women have double the rate of laryngeal cancer of white men and women, respectively. Hispanics have the lowest rates of oral cavity/pharyngeal cancer, and Asians have the lowest rates of laryngeal cancer.

The median age at diagnosis for HNSCC is approximately 60 years, but the incidence of these cancers in young adults (age < 40 years) appears to be increasing. This increase has not been apparent in blacks, and carcinoma of the tongue appears to account for the majority of this increase in incidence.

While head and neck cancer is relatively rare in the United States, it is the fifth most common cancer worldwide. Furthermore, in some parts of the world, these represent the most common malignancies found in men. For example, in South Central Asia, home to one-fifth of the world’s population, head and neck cancer accounted for approximately 155,400 new cases of cancer in 1990 (17% of all cancers and 25% of all cancers occurring in men). While the 80% of head and neck cancers in South Central Asia are oral cavity and pharyngeal (excluding nasopharyngeal) cancers, in other regions of the world, laryngeal cancers and nasopharyngeal cancers account for a much higher percentage of head and neck malignancies. For example, in the developed world, laryngeal cancer accounts for approximately one -third of head and neck cancers; and in Southern and Eastern Europe, approximately 40% of all head and neck cancers are laryngeal cancers. In China, nasopharyngeal cancer accounts for 55% of all head and neck cancers, and in South-Eastern Asia, nasopharyngeal cancer accounts for 70% of all head and neck cancers and 5% of all cancers in men.

Prevalance
In 1998 in the United States, the prevalence of HNSCC was 313, 105, with 219, 175 individuals with a history of oral cavity/pharyngeal cancer and 93,930 individuals with laryngeal cancer history. As expected, the sex distribution of these prevalence figures reflects the sex distribution of the incidence of these cancers. However, in 1998 African Americans accounted for only 11.8% of the prevalent population of individuals with a history of laryngeal cancer and only 7.9% of the prevalent population of individuals with oral cavity/pharyngeal cancer. These small percentages of the prevalent populations of these cancers likely reflect the poorer overall survival of African Americans diagnosed with HNSCC. African Americans have demonstrated survival rates approximately 20% worse than whites for oral cavity/pharyngeal cancer and 10% worse than whites for laryngeal cancer over the past 25 years. Not only has the discrepancy in survival between whites and blacks remained relatively constant over the past three decades, but neither whites nor blacks have seen significant gains in survival over this time period.

Worldwide, head and neck cancer is the third most prevalent cancer after breast and colorectal cancers, accounting for 7% of the 22.4 million individuals with a cancer diagnosis excluding nonmelanoma skin cancer. Of the approximate 1.6 million individuals with a head and neck cancer diagnosis, 707,100 have a diagnosis of oral cavity cancer, 458,100 have a diagnosis of laryngeal cancer, 248,800 have a diagnosis of oro/hypopharyngeal cancer, and 171,500 have a diagnosis of nasopharyngeal cancer.

Mortality
In the United States, approximately 11,000 individuals will die from head and neck cancer in 2003, with 5,200 of these deaths due to oral cavity cancer, 2,000 due to pharyngeal cancer, and 3,800 due to laryngeal cancer. However, head and neck cancer accounts for less than 2% of all cancer deaths in the United States annually. While today pharyngeal cancers account for less than half the number of deaths as they caused in 1985, oral cavity and laryngeal cancers account for approximately the same number of deaths as they did in 1985.

In the United States, the sex distribution for head and neck cancer deaths is similar to the sex distribution for the incidence of these cancers. While the mortality rates (age-adjusted to the 2000 US Standard Million Population) for oral cavity/pharyngeal cancers has declined steadily over the past two decades, the mortality rate for laryngeal cancer has only declined in white men. Blacks have higher oral cavity/pharyngeal and laryngeal cancer mortality rates than whites. Hispanics have the lowest oral cavity/pharyngeal cancer death rates, while Asians have the lowest laryngeal cancer death rates.

Worldwide, head and neck cancer accounts for 333,400 deaths annually, with 127,900 due to oral cavity cancers, 89,100 due to laryngeal cancers, 78,700 due to oro/hypopharyngeal cancers, and 37,800 of these due to nasopharyngeal cancers. As with other cancer sites, mortality/incidence ratios for head and neck cancers are much higher in developing countries for both men and women as compared to the United States. This likely reflects the better survival for these cancers seen in the United States; however, an opposite trend is seen for nasopharyngeal cancer.