Understanding new medical jargon, learning about seemingly foreign treatment modalities, and handling myriad appointments with different specialists can be overwhelming.
Here’s a basic guide to understanding radiation therapy as it applies to the head and neck cancers as well as what to expect when receiving head and neck radiation.
Radiation delivery is usually “fractionated,” or spread out, into small doses over a five to six week period during which one receives radiation daily for five days.
Before you receive your radiation, you will be given an appointment for a ‘simulation’ date. The simulation appointment is the treatment planning session during which your radiation treatment is mapped out. This is an extremely important appointment as the dosage and exact location of the radiation that will be delivered are determined at this time.
During the simulation appointment, you will lie on your back and a mesh facemask may be fabricated to maintain your positioning. If a mask is fabricated, you will wear this mask at every appointment. It is recommended that you visit a dental oncologist prior to the simulation as the measurements and planning completed during the simulation appointment are based on how you present the day of the simulation so any changes in your mouth, such as loss of teeth, will result in changes in the measurements and planning of the radiation dosage.
Before undergoing radiotherapy, your dentist may recommend that you wear radiation mouth guards during your treatment. When radiation hits metal in a person’s mouth, the radiation scatters and may be associated with an increased risk for developing mouth sores. Thus, it is often recommended that patients wear custom radiation mouth guards when undergoing radiation if the metal in their mouth will be in the field of the radiation. The mouth guards do not eliminate the risk of developing mouth sores, but may help reduce the risk by preventing the soft tissue from directly touching the intraoral metal. Nonetheless, radiation mouth guards are not always indicated. They are recommended depending on the amount of metal fillings you have in your mouth, the dosage of radiation that you will receive, and the location of the radiation.
After the simulation appointment, you will be given an appointment to return for a set-up appointment as well as treatment sessions.
Radiation Side Effects
Xerostomia is the medical term for the sensation of dry mouth. Hyposalivation signifies a reduction in salivary flow and is an objective, measurable entity. Radiation therapy affecting the head and neck where the salivary glands are in field of radiation is associated with salivary gland atrophy. Radiation doses of 25 Gy or greater are associated with hyposalivation, reduced salivary flow and function. In addition to reduced flow, the saliva produced is ropey, thick and predominantly mucus. The extent of hyposalivation and xerostomia felt is linked to the dosage of radiation received as well as the location of the field of radiation. As saliva acts as a natural buffer in the mouth, bathing and lubricating the teeth and oral tissues, reduced salivary flow leaves patients prone to an increased risk for dental decay. Additionally, xerostomia is associated with taste alterations, difficulty swallowing and difficulty speaking.
Trismus is the medical term for limited or reduced opening of the jaw. Trismus is often seen three to six months after radiation therapy due to radiation fibrosis. The degree of trismus varies depending on the radiation dosage, the location of the radiation as well as the patient’s medical history and age. Nasopharyngeal and oropharygneal carcinoma treatment appears to be more commonly associated with trismus than other head and neck cancers.
Depending on the location of the radiation, some patients may experience a sore throat. Although you may be tempted to dissolve on lozenges throughout the day, it is important to dissolve sugar-free lozenges to prevent rapidly developing rampant dental decay. The extent of the sore throat and duration is related to the radiation dosage and field of radiation.
Mucositis, literally inflammation of the mucosa, is characterized by mouth sores, intraoral redness, and a burning sensation. It is an acute side effect and is also associated with chemotherapy. Not all patients experience mucositis. Additionally, the extent and degree of mucositis varies among patients. Traditionally, mucositis is most commonly seen in the second week of radiation therapy, and patients experience resolution weeks after completing radiation treatment.
Hypogeusia signifies a reduced taste sensation, while dysgeusia means an altered sense of taste. It is very common to experience taste alterations or loss of taste sensation while undergoing treatment. Many patients state that the first taste bud to change is that which is responsible for sweetness. The extent of taste loss and the duration of taste alteration depend on several factors including radiation dosage, location of the radiation field, and the salivary flow. Saliva enhances the body’s ability to detect taste. Radiation doses of 60 Gy or higher may be associated with permanent taste alterations depending on the location of the tongue within the radiation field.
Osteoradionecrosis of the jaw (ORN) is a condition characterized by an area of exposed bone in the maxillofacial area that was previously irradiated. It is a complicated and involved pathological process. Essentially, ORN is a late side effect of radiation therapy, occurring six months to one year after treatment and is associated with radiation doses of greater than 60 Gy. It is most commonly associated with trauma to the tissues overlying the bone rather than direct trauma to bone such as extractions or periodontal (gum) surgery. Nonetheless, ORN can occur spontaneously. Regular dental visits may help to minimize the risk for developing ORN. Additionally, prior to receiving radiation therapy, it is advisable to visit a dental oncologist for a pre-radiation dental evaluation. Prior to receiving radiation to the head and neck, any non-restorable teeth that will be in the field of radiation should be extracted. Extractions of teeth in the field of radiation (if the total radiation dosage was greater than 50-60 Gy) after radiation therapy should be avoided.
Nutritional deficiencies may occur as a result of the loss of taste sensation, dry mouth and mouth sores. Despite these side effects, it is important to maintain caloric intake to prevent weight loss.
Preventing Side Effects
It is important to visit a dental oncologist before beginning radiation therapy for a thorough dental evaluation. At this evaluation, the dentist will determine if you need any dental treatment prior to beginning radiotherapy. Dental treatment such as tooth extraction(s) may be recommended before beginning treatment depending on where you will be receiving radiation and the dosage that will be delivered. If extractions are recommended, it is ideal to allow 10-14 days of healing time prior to starting radiation therapy.
Visiting a dental oncologist prior to receiving head and neck radiation therapy helps minimize the risks of developing the side effects.
If you are given radiation mouthguards, remember to bring them to your simulation appointment and leave them there so that you wear them at every radiation treatment session.
If you have a tooth/teeth extracted, you should ideally allow for 10-14 days of healing time prior to starting radiation therapy.
After receiving radiation therapy to the head and neck, be sure to inform your dentist of your radiation history before any invasive dental procedures as they may not be indicated depending on the dosage and location of your radiotherapy.
Epstein, Joel, Carl Haveman, Michaell Huber, Douglas Peterson, Jacqueline Plemons, Spencer Redding, Nicholas Sanfilippo, Mark Schubert, and Stephen Sonis. Oral Health in Cancer Therapy: A Guide for Health Care Professionals. 2008. Monograph compilation from 2008 Conference. University of Texas Health Science Center, San Antonio.
“Radiation Therapy for Cancer.” National Cancer Institute. National Cancer Institute, n.d. Web. 08 Oct. 2014.
“Radiation Therapy to the Head and Neck.” Memorial Sloan Kettering Cancer Center. Memorial Sloan Kettering Cancer Center, n.d. Web. 09 Oct. 2014.