Conditions: Radionecrosis
WHAT is Radionecrosis?
Radionecrosis is a condition characterized by the death of tissue following exposure to radiation. It often occurs after radiation therapy for cancer, as the treatment aims to destroy malignant cells but can inadvertently affect surrounding healthy tissue. The damage is typically gradual and may not manifest until several months or even years after treatment.
The mechanisms leading to radionecrosis involve a combination of direct cellular damage from radiation and subsequent inflammatory processes. Blood vessels supplying the affected tissues can become damaged, leading to reduced blood flow and oxygen deprivation. This can ultimately result in necrosis, or cell death, contributing to a variety of symptoms depending on the location of the affected tissue.
Radionecrosis is most commonly observed in tissues that have received high doses of radiation, with the brain, skin, and bones being the most frequently impacted areas. Symptoms may include pain, swelling, and, in some cases, ulceration of the skin or altered function of the affected organ.
Diagnosis typically involves imaging studies like MRI or CT scans, which can reveal changes in tissue structure, and this helps differentiate radio necrosis from tumor recurrence or other complications. Treatment options vary based on the severity of the condition and may include medications to manage symptoms, surgical intervention to remove necrotic tissue, or hyperbaric oxygen therapy to improve tissue healing.
what is osteoradionecrosis?
Osteoradionecrosis (ORN) is a condition characterized by the death of bone tissue due to radiation therapy, commonly used in the treatment of head and neck cancers. The radiation can impair the blood supply to the bone, leading to tissue necrosis. This condition is typically observed in areas that have received high doses of radiation and with relatively low blood supply. The mandible, or lower jaw bone, is at high risk for osteoradionecrosis when the targeted cancer is of the oral cavity or throat (especially the tonsils or base of tongue).
Osteoradionecrosis of the mandible can be extremely dangerous. When present, the dead bone can become infected and break, leading to a challenging situation of a dead, broken, infected lower jaw bone with a previously radiated (and therefore less able to heal) area requiring surgery. In some cases, the loss of a segment of the mandible will lead to a distorted mouth with disfigurement and impaired functionality for speech, eating or drinking. Long term gastric tube feedings may be necessary when swallowing cannot be performed safely.
Early clinical manifestations of ORN may include pain, swelling, ulceration of the skin or mucosa, exposed bone, and the potential development of infections. It can significantly impact a patient's quality of life and complicate dental and surgical procedures.
The pathophysiology of ORN involves several factors, including hypovascularity (low concentration of blood vessels), hypoxia (low oxygen delivery), and alterations in the biochemical environment of the bone, which can lead to a reduced ability to heal and regenerate.
While prevention strategies, such as dental evaluation and treatment before radiation therapy, are critical, the risk of ORN remains a concern for patients undergoing radiation in the head and neck region.
What are the risk factors for mandible osteoradionecrosis?
Poor dental health
History of heavy alcohol use
Smoking while undergoing radiation treatments
Use of chemotherapy in addition to radiation therapy
History of prior radiation to the area
Diabetes
how can mandible osteoRADIONECROSIS be prevented?
Modifiable factors for preventing mandibular osteoradionecrosis involve a combination of careful planning, technique, and ongoing patient management. Here are several strategies that can help in its prevention:
Dental evaluation and treatment before radiation. Evaluation by a dentist familiar with osteoradionecrosis is necessary. Since radiation accelerates dental decay, unhealthy teeth must be treated aggressively before radiation can start. This may include placing fillings or extracting teeth.
Maintaining good oral hygiene during and after radiation. An oral hygiene regimen including careful teeth brushing, flossing and use of cleansing rinses and/or fluoride trays is important.
Not smoking. Assistance with this may be obtained through one’s primary physician and also by calling the free 1-800-QUIT-YES automated hotline.
Technical aspects of the radiation therapy, including accurate dosimetry, good treatment planning, use of dose fractionation are incorporated into the radiation oncologist’s treatment plan to minimize risk of mandibular osteoradionecrosis.
Dental evaluation and consideration of hyperbaric oxygen therapy when dental extraction is necessary after radiation therapy has been completed. That is, someone who previously underwent radiation around the mandible who needs extensive dental work, such as extraction of a tooth or teeth, should be evaluated for receiving hyperbaric oxygen therapy before and after the dental work is undertaken in order to minimize the risk of complications, such as a dry socket, bone infection, bone death, and a fractured jawbone. A dentist who is familiar with mandible osteoradionecrosis is necessary and may need to consult with the radiation oncologist regarding the dose of radiation delivered to the mandible.
How is mandible osteoradionecrosis identified?
Mandibular osteoradionecrosis (ORN) can be identified through a combination of clinical assessment, imaging studies, and patient history following radiation treatment. Frequent assessment by a head and neck cancer physician is necessary after radiation treatment to assess for ORN as well as to assess for other treatment related problems and for recurrence of cancer.
Clinical assessment includes noting symptoms such as pain, swelling, and non-healing ulcers in the oral cavity. Your physician’s examination findings that would be suggestive of ORN include observing exposed mandible bone, loose or broken teeth, swelling or pus around the mandible, and possibly a draining fistula through the nearby skin.
Imaging studies, including panoramic radiography or CT imaging may be used to demonstrate the extent of ORN.
how can mandibular osteoRadionecrosis be treated?
The management of radio necrosis is challenging and typically includes some or all of the following interventions:
Symptomatic Treatment: Addressing symptoms such as pain and inflammation can provide some pain relief. This can involve the use of medications for pain such as anti-inflammatory medications and sometimes steroids.
Surgery: In cases where radionecrosis leads to significant tissue damage or necrosis, surgical intervention to remove dead tissue may be necessary. When large segments of tissue require removal, surgical reconstruction may also be necessary to restore functionality.
Medications: A medication regimen including 800 mg pentoxifylline daily, 1000 IU of tocopherol (vitamin E) daily, and sometimes vitamin D, along with frequent use a cleansing mouthwash (chlorhexidine 15 mL swish and spit after meals and before bed) has potential to improve tissue healing and prevent further necrosis. Antibiotics may be used for special cases in which infection is also present.
Hyperbaric Oxygen Therapy (HBOT): This therapy involves breathing pure oxygen in a pressurized environment, which may help to promote healing in damaged tissues, enhance oxygenation, and stimulate growth of new blood vessels.
Speech and Swallowing Therapy and Physical Therapy: Mandibular ORN, like radiation to the mouth or throat in general, risks detrimental effects on speech, swallowing, and jaw movement. Evaluation and treatment by a speech and language pathologist for swallowing is an important component of recovery. Range of motion exercises for the jaw joint, often facilitated by a physical therapist or speech pathologist, can help prevent or minimize trismus (inability to fully open the jaws).
Monitoring and Follow-up: Regular monitoring of the affected area is essential to assess the progress of treatment and modify approaches as needed.
The treatment plan for radionecrosis should be tailored to the individual patient, taking into consideration factors such as the location and severity of the necrosis, the patient’s overall health, and their past medical history. Collaboration among oncologists, surgeons, radiologists, and rehabilitation specialists facilitates optimal management.
