Head and neck cancer: from anatomy to biology

Abstract

The 20th century saw great advances in anatomy-based (surgery and radiotherapy) and chemotherapy approaches for treating head and neck squamous cell carcinoma (HNSCC) and improving quality of life (QoL). However, despite these advances, the survival rate in HNSCC remains at~50%. Front-line treatments often cause severe toxicity and debilitating long-term impacts on QoL. In recent decades, dramatic advances have been made in our knowledge of fundamental tumor biology and signaling pathways that contribute to oncogenesis and cancer progression. These insights are presenting unprecedented opportunities to develop more effective and less toxic treatments that are specific to particular molecular targets. This review discusses some of the major, potentially targetable, molecular pathways associated with head and neck carcinogenesis. We present the general mechanism underlying the functional components for each signaling pathway, discuss how these components are aberrantly regulated in HNSCC and describe their potential as therapeutic targets. We have restricted our discussion to "drugable targets" such as oncogenes including those associated with HPV, tumor hypoxia and microRNAs and present these changes in the context of HNSCC patient care. The specific targeting of these pathways to achieve cancer control/remission and reduce toxicity is now challenging conventional treatment paradigms in HNSCC. This new "biologic era" is transforming our ability to target causal pathways and improve survival outcomes in HNSCC.Head and neck cancers include malignancies of the oral cavity, nasopharynx, oropharynx, hypopharynx, larynx, paranasal sinuses and salivary glands. Squamous cell carcinoma is the most common histological type of head and neck cancer, accounting for 90% of all head and neck malignancies. Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide. 1 However, there are dramatic differences in HNSCC incidence across the globe; for example, in India, HNSCC is the most common cancertype in the population accounting for 40% of all malignancies. 2 Cancers of the oral cavity and oropharynx are the most common HNSCC. Oral squamous cell carcinoma (OSCC) and oropharyngeal squamous cell carcinoma (OPSCC) accounted for 263,900 new cases and 128,000 deaths worldwide in 2008. 3

Tumor-Associated Tissue Eosinophilia in Squamous Cell Carcinoma of Head and Neck

“…Tobacco, alcohol and human papilloma virus are important risk factors for this cancer (6). Clinically, head and neck squamous cell carcinoma (HNSCC) has a high tendency toward local recurrence or regional lymph nodes metastasis.…”

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“…Head and Neck squamous cell carcinoma is the most common type of cancer type in India, accounting for 40% of all malignancies. [3,4] The constantly increasing number of HNSCC and successful surgical treatment render cases for definitive restorations to re-established Quality of life.…”

Impact of Pain and Evaluation of Education and Self-Care in Patients with Head and Neck Cancer

“…Tobacco, including smokeless tobacco and betel quid chewing, are important risk factors that underlie the majority of HNC; 50-80% of HNC are associated with tobacco exposure [5,6]. Smokers are at ten times the risk of HNC compared with non-smokers [5].…”

“…Squamous cell carcinoma is the most common histological type of HNC and may originate from the mucous membranes of the oral cavity, pharynx, larynx, nose and sinuses. Also included in the HNC group are salivary gland malignancies, the most common histology being adenocarcinoma, and thyroid cancers, generally characterised by histology showing papillary cancer [4,5]. For the National Cancer Institute © 2012 Terese Winslow LLC, U.S. Govt.…”