Today I’d like to talk about an important topic: head and neck cancer. I’ll be writing the next few posts on this topic in more detail. I’ll mainly be focusing on cancers that form inside the mouth and throat. I’ll not be discussing thyroid cancers, which are treated quite differently.
I saw a ton of head and neck cancers as a resident, but not very many since then. The reason is that these cancers are not extremely common, and the majority of them are referred by community docs to academic centers for treatment (especially the cancer patients that need surgery for treatment).
Over 95% of cancers in the mouth and throat are a variety called squamous cell carcinoma. These cancers arise from the lining of the mouth and throat, which normally is a squamous epithelium (squamous means flat, and under the microscope, the cells are in thin, flat layers). If these normal cells accumulate enough damage to their DNA, they can begin growing uncontrollably and invading the surrounding tissue, and thus become a cancerous tumor.
The major risk factors for head and neck cancer are tobacco and alcohol use. Smoking increases risk for all types of mouth and throat cancer, while chewing tobacco only increases risk for mouth cancer. Heavy alcohol use can also increase risk for head and neck cancer, especially in people who also smoke.
Another important risk factor for throat cancer that has arisen in the past 20 years is Human Papilloma Virus (HPV) infection. This virus has lead to a significant increase in throat cancers in nonsmokers. HPV is also responsible for most cervical cancers in women.
Other risk factors include male gender, older age, family history of cancer, and radiation exposure.
Squamous cell cancers (SCCAs) of the head and neck can present in a variety of different ways. Mouth cancers can usually be seen easily and are detected by the patient. Throat cancers can be more difficult to detect- they typically present with symptoms of persistent throat or ear pain, difficulty swallowing, or as a lump in the neck (from cancer that has spread to a lymph node). Cancers of the voice box can also cause hoarseness as the presenting symptom.
With any suspected cancer patient, the first order of business is to confirm the diagnosis with a biopsy. In mouth cancer, this can usually be done easily in the office. For patients with cancer that has spread to the lymph nodes in the neck, a needle biopsy of the enlarged node can be done. I will typically order radiologic imaging of the neck and chest as well. Usually this is a CT scan of the neck and either a chest X-ray or chest CT.
Every patient should have an endoscopic exam of their mouth, throat, and esophagus as part of the diagnostic workup for any head and neck cancer. The reason is not only to closely examine the tumor and get biopsies, but also to look for second tumors (these can occur in up to 10% of patients in some studies).
Occasionally, patients will present with an enlarged lymph node in the neck which shows squamous cell carcinoma on needle biopsy. However, all their scans and their endoscopy shows no evidence of any tumor in their mouth, throat, or esophagus. Usually, I will take “targeted biopsies” of areas where small tumors are known to hide (tonsils, base of tongue, nasopharynx, etc). Assuming all these areas show no cancer, the patient has what is known as an “unknown primary” tumor. Interestingly, these patients actually carry a better prognosis than patients with known primary tumors.
I will always have patients be evaluated by a radiation oncologist and medical oncologist as well and once we have a definitive diagnostic biopsy and adequate imaging showing the extent of the cancer, we can recommend the best treatment for each patient.
The next post will give an overview of the prognosis for head and neck cancer and the options for treatment.