Head and neck squamous cell carcinoma

Head and Neck Cancers are malignant neoplasms that arise in the head and region which comprises nasal cavity, paranasal sinuses, oral cavity, salivary glands, pharynx, larynx. The majority of head and neck cancers histologically belong to squamous cell type and hence they are categorized as Head and Neck Squamous-cell carcinoma, abbreviated as HNSCC (Forastiere AA, 2003). HNSCC is the sixth most common type of cancer world-wide and account for ~ 5% of all malignancies world-wide (Ferlay J, 2010) and 3% of all malignancies in the Unites States (Siegel R, 2014). Risk factors include tobacco consumption (chewing or smoking), alcohol consumption, human papilloma virus (HPV) infections (esp. HPV 16, 18), betel nut chewing, wood dust exposures and others (NCI Factsheet, 2013). Symptoms include lump or sore, sore throat, hoarse of voice, difficulty in swallowing etc (NCI Factsheet, 2013). Treatment for HNSCC is based on the stage of the disease. Standard of care for HNSCC includes one or combination of the following: surgery, radiation, chemotherapeutic agents such as Cisplatin, 5-Flurouracil (5-FU) etc. Molecularly targeted therapies were developed since the discovery of role of epidermal growth factor receptor (EGFR) signaling in HNSCC development, progression and prognosis. These targeted therapies include monoclonal antibodies (such as cetuximab, panitumumab etc.) and tyrosine kinase inhibitors (such as erlotinib, gefinitib etc.). Among these EGFR-targeting agents, only cetuximab has been approved by FDA in 2006 for HNSCC treatment.

Biopsy of a highly differentiated squamous cell carcinoma of the mouth. Haematoxylin & eosin stain.

Ninety percent^[1] of cases of head and neck cancer (cancer of the mouth, nasal cavity, nasopharynx, throat and associated structures) are due to squamous cell carcinoma. Symptoms may include a poorly healing mouth ulcer, a hoarse voice or other persistent problems in the area. Treatment is usually with surgery (which may be extensive) and radiotherapy. Risk factors include smoking, alcohol consumption and hematopoietic stem cell transplantation.^[2] In addition, recent studies show that about 25% of mouth and 35% of throat cancers are associated with HPV. The 5 year disease free survival rate for HPV positive cancer is significantly higher when appropriately treated with surgery, radiation and chemotherapy as compared to non-HPV positive cancer, substantiated by multiple studies including research conducted by Maura Gillison, et al. of Johns Hopkins Sidney Kimmel Cancer Center.

References