There are four options available to us currently that have a role in attempting to achieve cure for our head and neck cancer patients. They are surgery, radiation, chemotherapy and immunotherapy. We sometimes use them individually or in combination with one another, not only to remove disease, but prevent it from coming back. In general the earlier the stage of cancer, the simpler the treatment, with only one of the treatment modalities being necessary. The more advanced the cancer, the more likely combinations of those treatment modalities will be recommended.
Surgery to remove cancer in the head and neck is the oldest modality and has been around for over a hundred years. The main goal of surgery is to remove all evidence of cancer, or areas suspected of harbouring cancer, while protecting and preserving vital structures that affect quality of life. Particularly nerves are the most important structures in the head and neck for the surgeon to preserve. The risk of having long and complicated surgery, even in elderly patients, has significantly decreased over the years related to our better understanding of peri-operative physiology and multidisciplinary input.
Today, almost all thyroid cancer, salivary gland cancer and most skin and oral cancer is best treated primarily with surgery. The surgical techniques for these operations have not changed very much over the years, except for some minimally invasive techniques such as trans-oral CO2 laser microsurgery for upper aero-digestive treat cancers. This technique as well as robotic surgery doesn’t improve overall survival more than the traditional open techniques, but they do lessen morbidity and suffering. We use the trans-oral laser microsurgery in our unit for early mouth, oropharynx, larynx and hypopharynx cancers.
Surgery also often involves removal of lymphs nodes to where the cancer has spread or suspected to have spread. This is called a neck dissection and usually performed at the time of surgery on the primary site. If radiation has been decided on as the primary modality of therapy for a primary cancer, then radiation is used to treat the neck also.
Radiation treatment works by damaging the DNA of cells, and we rely on healthy non-cancerous cells recovering from this treatment, while trusting that cancerous ones won’t. The targeting techniques have greatly improved over the years to reduce the collateral damage to healthy tissues, but there are still effects that patients can struggle with. These effects can be broadly divided into early and late effects. The most common early effects are xerostomia (dry mouth) related to damage to salivary glands, loss of taste, mucositis (mouth ulcers), skin changes, and general mental and physical tiredness. Depending on where in the head and neck the radiation is directed, long term effects can include dysphagia(difficulty swallowing) related to scarring of swallowing muscles, degradation of teeth and neck stiffness.
The cure rates for treating early upper aero-digestive tract cancers like mouth and larynx with radiation are as effective as treating with surgery, so after good counselling discussing the pros and cons of each, patient preferences often determine the final decision.
Some cancers like nasopharynx and oropharynx cancers respond very well to radiation and are often used as first line therapy. The use of chemotherapy in head and neck surgery has traditionally been ineffective for cure on its own, but when combined with radiation, in particular for nasopharynx and oropharynx cancers, it increases the chance of survival significantly. Unfortunately the side effects are more, but these can be minimised and managed. We sometimes use chemotherapy as induction to shrink the tumour prior to combination chemo-radiation. Chemotherapy on its own has a role in palliation of patients when cure is no longer an option.
Immunotherapy is the most promising development in the world of oncology care. Unlike chemotherapy which is a toxin that preferentially kills cancer cells, immunotherapy relies on activating the patient’s own immune system around cancer cells to kill the cancer. The side effect profile is less, however we are not at a stage where we can accurately predict who will respond to it. It is very expensive often needing to be given for 3 to 24 months before we know whether it works and funders don’t always pay for it. Currently we use it only when all other forms of treatment have failed to control the disease. It works about 20 percent of the time.