Head and Neck Cancer

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Head and Neck Cancer
University of California, San Diego Medical Center

Overview

The Head and Neck region is comprised of a large number of tissues and organs. Major components include the oral cavity (mouth), oropharynx, nasopharynx, supraglottic and glottic larynx (“voice box”), and hypopharynx.

Multiple sinuses are included in the head and neck region including the frontal, ethmoid, sphenoid, and maxillary sinuses. Various glands are located in this region as well including the thyroid gland and salivary glands.



Head and Neck cancers comprise approximately 3% of all cancers, with nearly 40,000 new cases diagnosed each year in the United States. A major tumor site is the larynx (12,000 new cases), predominantly arising in the vocal cords followed by the supraglottic larynx.

Hypopharyngeal and nasopharyngeal tumors account for approximately 2500 and 2000 cases each year in this country, respectively. Outside the United States, nasopharyngeal cancer is more common, particularly in Asia and South Africa.

Head and Neck cancers present with a wide spectrum of signs and symotoms, depending upon the organs involved and the tumor extent. Early larynx (voicebox) tumors may present with symptoms of hoarseness, more advanced tumors may impair swallowing. Tumors of the mouth (oral cavity) typically present with an ulcer and pain, sinus tumors may present with nasal stuffiness or nasal bleeding (epistaxis).

A common site of spread is to the regional (neck) lymph nodes. Tumors arising on one side preferentially spread to the same side of the neck. Centralized tumors, as well as more advanced lesions, may result in lymph node involvement on both sides of the neck. In some patients, an enlarged lymph node in the neck is the one and only presenting symptom and the primary tumor is never found (“unknown primary”).

Interested in learning more about head and neck cancers? Check out the American Cancer Society website.

Role of Radiation Therapy

In many head and neck cancer patients with early stage tumors, the treatment of choice is surgery. Radiation therapy is used following surgery in patients found to have “high risk” features, for example involved (positive) tumor margins and spread to regional lymph nodes. In many head and neck cancer patients, Radiation therapy may be used alone or, more commonly today, combined with chemotherapy (view paper).

In some early stage head and neck cancer patients, the treatment of choice may be radiation instead of surgery. For example, small tumors of the vocal cords are preferably treated with radiation since radiation therapy is associated with better voice quality than surgery (view paper). One head and neck tumor site in which surgery is never the treatment of choice, even in patients with early stage disease, is the nasopharynx.

Radiation Therapy has long been the treatment of choice in patients with locally advanced disease. In such patients, radiation therapy is typically delivered combined with chemotherapy [link to Head Neck Paper C]. Such patients may also undergo surgery prior to or following radiation.

Radiation Therapy Techniques

For many years, the standard approach in the majority of head and neck cancer patients involved opposed lateral fields encompassing the primary tumor sites and regional (neck) lymph nodes. While effective, this approach commonly resulted in considerable toxicity due to the irradiation of the salivary (parotid) glands. Consequently, many patients treated with such techniques suffered with long-term dry mouth (xerostomia).

Today, opposed lateral fields have given way to a more sophisticated approach to radiation therapy known as intensity modulated radiation therapy (IMRT). Unlike conventional approaches, IMRT conforms the radiation dose to the shape of the target tissues in 3-dimensions, reducing the dose delivered to the nearby normal tissues including the salivary glands. IMRT has been shown to be associated with excellent outcomes with less damage to the salivary glands.


IMRT Plan in a patient with a right tonsil cancer

IMRT is the standard approach in all head and neck cancer patients treated at UCSD.

Simultaneous Integrated Boost (SIB)

IMRT provides the ability to not only conform the radiation dose to the shape of the target thereby reducing dose to normal tissues, it also allows the radiation oncologist to deliver different doses each day to different parts of the target. This approach is known as a simultaneous integrated boost (SIB).

The SIB approach provides the ability to deliver higher than conventional doses safely to the tumor and involved lymph nodes while reducing the overall treatment course. Patients treated in this fashion are able to complete treatment faster than patients treated with conventional techniques. Not only is treatment delivered faster, it is more effective than standard approaches.

Amifostine (Ethyol)

While IMRT significantly reduces the risk of dry mouth (xerostomia) in head and neck cancer patients undergoing radiation therapy, in many patients, for example patients with large (bulky) lymph nodes adjacent to the salivary glands, it is not always possible to avoid high doses to the salivary glands. In these patients, dry mouth is unfortunately still a common concern.

At UCSD, such patients are treated with a combination of IMRT and a drug known as amifostine (ethyol). Amifostine belongs to a group of drugs called cytoprotectants, which protect normal tissues from some of the side effects caused by some treatments for cancer, including radiation.

Amifostine provides these protective effects after being broken down (metabolized) in the body. Through various chemical reactions, the metabolites of amifostine deactivate molecules that result in tissue damage from radiation.

Healthy cells are preferentially protected since amifostine and its metabolites are taken up significantly better by healthy than tumor cells. This preferential uptake is why amifostine is unlikely to protect the tumor itself from radiation.

Amifostine is typically administered intravenously (into a vein). Amifostine is given approximately 15-30 minutes priot to radiation. Because low blood pressure may result, patients receive the drug lying down, have their blood pressure frequently monitored and may receive intravenous fluids.



To learn more about Ethyol (Amifostine), patients can consult the MedImmune website and/or the Package Insert.