Tratamiento del Cancer   /   Radiación   /   Efectos Secundarios

Effects of Radiotherapy on the Oral Cavity

Jay Lucas, DMD, MD, David Rombach, DMD, MD, Joel Goldwein, MD
Ultima Vez Modificado: 1 de noviembre del 2001

INTRODUCTION

Approximately one million people will develop invasive cancer each year. Of these, 40% will receive curative benefit from surgery, radiation, chemotherapy, or a combination modality.(5) In dealing with patients with cancer of the head and neck a team approach is required for effective management. When radiation therapy is indicated, it is imperativ that health of the oral cavity be assessed initially as well as throughout therapy.

All members of the cancer treatment team should be informed of the oncologic treatment plan. Oral care should be initiated at the onset of treatment, with the goal of reducing morbidity and improving compliance. Total body irradiation and irradiation to the head and neck cause both direct and indirect effects on oral and related structures, and may be acute or chronic in nature. These complications may include mucositis, xerostomia, dental caries, loss of taste, trismus, infection, osteoradionecrosis, and abnormalities of growth and development.

Pre-radiation Therapy Management Considerations

Oral complications can affect the patient's tolerance to radiotherapy and quality of life. Pre therapy dental evaluation can decrease the incidence and severity of these complications. Strategies include:

• A. A complete dental examination to identify preexisting problems. Cancer diagnosis, past medical history, dental history, dental charting, periodontal charting, radiographs, and nutritional status should be included. Prior to treatment, some clinicians may quantitate the amount of saliva and collect study models to assess changes during therapy. (1)

• B. Prior to treatment, potentially complicating diseases should be corrected. Poor oral hygiene, third molar pathology, periapical pathosis, periodontal disease, caries, defective restorations, ill fitting prostheses, orthodontic appliances and any other potential sources of irritation (tori) should be eliminated. Irritation and infection are important targets for early treatment to reduce the incidence of local and systemic infection. Intervention should be supplemented with plaque removal, including tooth brushing with fluoride paste and flossing if tolerable. Additional topical fluoride and chlorhexidine may be helpful to control caries and plaque. If time permits dental procedures, especially extractions, should be completed two to three weeks prior to the start of radiation.(1)

• C. Patient adherence to hygiene protocols are critical. Patient and family education, counseling, and motivation will increase the chances for success. All potential side effects should be identified.(1)

ACUTE AND SUBACUTE COMPLICATIONS OF RADIATION THERAPY

Acute reactions are those which arise during or shortly after radiation therapy and resolve within ninety days post-therapy.

Mucositis

One of the first symptoms of radiation complications is mucositis ,which occurs 12- 17 days after the initiation of therapy. Mucosal inflammation varies with dosage, target size and duration of therapy. Oral mucositis can present as patchy mild erythema to frank confluent ulceration. Chemotherapeutic agents such as 5FU, procarbazine, methotrexate, etc., may increase the severity of these symptoms. Currently, there are no drugs available to prevent mucositis, and it is imperative to distinguish these lesions from those caused by infections. Cultures may be needed to differentiate between fungal, bacterial and viral lesions versus those secondary to radiation effects.

Prevention, on the part of the Radiation Oncologist is essential to minimizing excessive morbidity of the oral mucosa . This is accomplished by designing portals that limit the exposure to tissues not at risk for tumor reoccurrence. When interstitial implants are a part of a treatment protocol, soft tissues of the oropharynx are at greater risk for developing soft tissue ulcerations.(5) Mucosa thickness, another important predictor of exaggerated tissue response, should be considered. The anterior commisures of the mouth and the medial surface of the angle of the mandible are sites which contain very thin mucosa and would benefit from field blocks if possible. (5)

Lack of saliva and damaged taste buds may alter the sensation of taste during radiotherapy. Often, patients complain that many foods taste excessively salty which may reduce the motivation for adequate oral intake. In response to their altered taste sensation, patients tend to compensate by increasing their intake of sugar. Counseling should be provided to avoid this behavior due to the increased risk of dental caries. However, altered taste sensorium is a transient phenomenon since the taste buds recover in two to four months post therapy.(1)

Management

Many untested topical oral preparations can reduce symptoms of oral mucositis. Efficacy and safety of these agents has not been established. Currently accepted elixirs include a combination of Benadryl, Kaopectate, MOM, antacids, sucralfate, corticosteroids, dyclonine, and viscous lidocaine.(2) If pain is severe enough to limit eating, systemic analgesia should be considered. Extremes in mucosal inflammation which demonstrate confluent lesions may warrant a treatment break to allow tissues to continue therapy. However, cessation in treatment can be dangerous by allowing rapid repopulation of tumor cells during breaks in therapy. Commercial mouth rinses should be avoided. The alcohol and phenols contained in these preparations may further dehydrate the mucosa causing further pain. Chlorhexidine should be continued during radiation therapy and may be diluted for tolerance.(2)

Xerostomia

Local and total body irradiation may irreversibly affect the production and quality of saliva in the major and minor salivary glands. Doses as low as 20 Gy will result in clinically noticeable changes such as sparse thick ropy saliva. In particular, if the parotid glands are in a field which received 40Gy or over, permanent dysfunction of the salivary glands should be expected and discussed with the patient prior to treatment. (1) Concomitant administration of medications which are known to induce xerostomia (i.e. psychotropics, antiemitics, antihistamines, and thousands of other commonly prescribed medications.) should be carefully considered.(1)

The diagnosis of xerostomia is based on subjective impressions by the patient and the clinician. Dry mouth may affect speech, taste, nutrition and the patients ability to wear a prosthesis. Saliva also contains antimicrobial compounds (i.e. sIgA, and mucins) which reduce pathogenic bacteria and decrease the risk of infection in the oropharynx . However, saliva's most important role lies in its ability to mechanically cleanse the teeth and soft tissues. Therefore, with radiation induced xerostomia it is common for this to lead to an increased incidence of caries, especially in the cervical portion of the clinical crown at the cementoenamel junction.(2) Similarly, the change in salivary content and quantity also leads to an increased incidence of candidiasis and periodontal disease.

Management

Management for xerostomia is directed at several levels. First, addressing the patients chief complaint of chronic dry mouth, treatment is generally palliative--utilizing artificial saliva, carrying water bottles for periodic mouth moistening. Salivary substitutes are available in two types. All contain electrolytes commonly found in saliva including those normally used for remineralization and should be used in dentate patients. The other solutions contain dextrans which should be reserved for edentulous patients so as not to raise the caries index. Sialogogues (pilocarpine) may also be used to stimulate saliva formation if residual salivary tissue remains. These drugs alleviate many of the problems encountered during therapy (1,2)

However, the critical aspect in managing head and neck irradiated patients with xerostomia is controlling the risks for oral diseases. Therefore, initiation of meticulous oral hygiene regimens including topical fluoride trays , chlorhexidine rinses, and regular dental hygiene therapy sessions are required. In addition, dietary advice is recommended to reduce the intake of carogenic foods.(2)

Candidiasis

Another acute effect commonly associated with mucositis is oral candidiasis. Colonization of the yeast on damaged tissue can intensify the symptomatic effects of radiation on the mucosa.(6)

The practitioner should be aware of the multiple presentation of candida including pseudomembranous (removable white plaques with an erythematous base), chronic hyperplastic (leukoplakia like plaques that do not wipe away), and chronic cheilitis. These infections should be eliminated to decrease mucositis and the chance of distant gastrointestinal infections.

Management

Management of patients with oral pharyngeal candidasis include both topical and systemic approaches. Historically, nystatin topical solution have been used with mixed efficacy. Patients involved in this therapy should be advised that the solution must be refrigerated at all times or the solution will become inactivated. Other topical solutions include clotrimazole troche which is recommended for edentulous patients and angular cheilitis. However, this medication should be avoided by the dentulous patient for caries control, due to its high sugar content. Currently, the best medication for oral or systemic candidiasis is Diflucan. The treatment regimen includes a 200mg loading dose the first day, followed by a 100mg /day dose for the remaining thirteen days. However, it is imperative that the physician obtain liver function tests prior to initiation of treatment because of the potential toxic side effects on the liver.(2)

Bacterial Infections

Local infections can lead to sialadenitis, periodonditis, abscesses, pericoronitis, or other causes of ulceration. Emperic treatment with antibiotics are usually adequate; however, periodontal lesions usually need additional debridement. The oral cavity may be the portal of entry for systemic infections. Therefore, chlorhexadine rinses should be considered for these patients.(2)

Bleeding

Gingival bleeding may be the first sign of thrombocytopenia. The patients' ability to accomplish adequate oral hygiene may be limited. In these instances flossing may have to be discontinued . Again chlorhexadine rinses may be required to reduce pathogens found in plaque.(2)

Chronic Complications of Radiation Therapy

Osteoradionecrosis

Certainly one of the most devastating complication of radiation therapy to the head and neck is the development of osteonecrosis of the mandible. Long term effects of radiation therapy on osseous and soft tissues is soft tissue fibrosis and ischemia, which may never resolve. The main mechanism of osseous involvement is injury which occurs to the small vasculature of the Haversian canals and the periosteal tissue. Fortunately, osteonecrosis is a relatively uncommon complication, with an incidence ranging from less than two percent to as high as 10%. This range in incidence varies with total dose administered to the mandible. (i.e. greater than 70 Gy yielding the larger number) Another compounding factor is location of the primary tumor. If the lesion is large and is situated at the floor of mouth the rate of osteonecrosis more than doubles to 25%.(6) Due to the decrease in healing capacity of the tissues from decreases in blood supply, infections to the jaw are devastating. The major etiologies are extraction of failed dentition after radiation therapy. Therefore, posterior mandibular teeth may be planned for extraction if more than 6,000 rads are expected in that field.

Great importance should be placed on pretreatment evaluation of all remaining dentition. Any questionable teeth that cannot be adequately maintained for years should be extracted. A period of two weeks prior to radiation therapy is advised for adequate healing of extraction sites. All preprosthetic surgery required, should be performed prior to the initiation of radiation therapy.(8)

Management

Occasionally systemic antibiotics will be required if osteoradionecrosis develops. Technically it is not an infection of bone but rather a nonhealing hypoxic wound. (8) Systemic antibiotics are of limited value to the mandible itself due to the decreased vasculature and subsequent poor drug delivery to the site. However, in secondary infections they may have a role in preventing the spread of infection. No attempt should be made initially to obtain primary soft tissue closure of bone, since most wounds less than 1 cm or less will heal in weeks to months without surgical intervention other than removing sequestrum.(8) For large defects in the jaw, surgery will be required with osseous and soft tissue reconstruction with the aide of preoperative and postoperative hyperbaric oxygen.

The role of hyperbaric oxygen has greatly enhanced the ability to reconstruct patients with osteoradionecrosis with large boney and soft tissue defects. However, the cost is tremendous and access to treatment is limited. Additionally it is felt that patients with active malignancies should not be exposed to HBO for fear that it can accelerate the repopulation process. The mechanism of action appears to be supporting neovascularization within tissues ,increasing the oxygen tension . The protocol is 20 pre- surgical hyperbaric oxygen (HBO) sessions, each consisting of 90 minutes of 2.4 atm of absolute pressure/day x five days /week. After the reconstructive surgery, an additional ten treatments is prescribed to ensure adequate vascularization of the grafted bone and soft tissue. There are contraindications to this treatment, covered on OncoLink and elsewhere (7)

Soft Tissue Necrosis

The primary etiologies for this type of chronic complication are due to excessive doses delivered to the tissues via interstitial implants or secondary to soft tissue irritation from an inadequate fitting prosthesis.(6,8) If the patient can tolerate being edentulous, it is recommended for the first six months post-therapy to allow for adequate healing and remodeling of bone. Occasionally it is required to administer HBO and antibiotics to alleviate the necrotic tissue.(6,8)

Trismus

This condition is secondary to fibrosis which occurs in the muscles of mastication after being within the field of radiation. Best management is to encourage physical therapy during and after the radiation is administered.(4) This feature can also be an important factor for adequate oral hygiene if the patient is unable to open the mouth for proper dental care.

Suggestions for the Edentulous Patients

Proper fitting of prostheses is essential, discrepancies can result in ulcers which may lead to osteoradionecrosis. New dentures should be constructed only after adequate healing time; in the interim, soft tissue liners may be used. Chlorhexidine two times a day until salivary function returns can be used to keep the mouth clean. Salivary analogues may also be used to increase retention of the dentures.(2)

Candida is often a problem and antifungals should be used. These drugs may be added into tissue conditioners or placed where needed. Dentures should be removed and cleaned every night. At first sign of discomfort, the denture should be removed, adjusted or relined. It is extremely important not to have soft tissue ulcerations, because the risk of osteoradionecrosis is a life-long threat.(8)

ORAL CHANGES FOLLOWING RADIATION THERAPY OF THE PEDIATRIC PATIENT

The advent of chemotherapy and radiotherapy as treatment modalities for pediatric malignancies has produced a significant increase in cure rates for many of these cancers. However, along with the increased success of treatment with these modalities comes a potential for multiple organ system morbidity that may last the lifetime of the patient. These modalities have found their niche in the treatment of head and neck cancers, and as such, many of these pediatric patients will survive into adulthood. With this increased survival there is an increased potential to develop significant long term complications within the treatment fields. It is therefore imperative that the health care team be familiar with not only the potential complications of therapy, but also their prevention, recognition and management.

Oral complications of radiotherapy are usually the result of the direct effects of radiation on the oral tissues. The tissues most frequently affected are the mucosa, salivary glands and mineralized tissues.

ACUTE EFFECTS OF RADIATION THERAPY TO THE HEAD AND NECK

Mucositis

Radiation associated mucositis is a direct effect of radiation on the oral mucosa. It is a result of a decrease in the turnover rate of the basal cells of the epithelium with subsequent thinning and ulceration of the mucosa. The minimum dose of radiation that will cause mucositis is not known. However a total dose of 600 cGy given in one dose or two fractions for leukemic gingival infiltrates usually causes mucositis.(9) These changes will usually appear 12 to 17 days following initiation of treatment and heals completely 2 to 3 weeks following the cessation of therapy. Management of mucositis typically consists of saline and/or bicarbonate lavage, analgesics such as topical xylocaine to relieve pain and facilitate oral intake of food and fluids. A severe mucositis may necessitate a break in treatment to allow healing. Candidal colonization of the inflamed ulcerated mucosa may occur requiring treatment with topical anti-fungal agents such as Nystatin or Diflucan.(4)

Xerostomia

Xerostomia, is another side effect of radiotherapy occurring when substantial salivary gland tissue is located in the portal of the radiation therapy. These effects have been observed within 24 hours of two to three fractions of 200 cGy total body irradiation. At higher doses such as 5000 to 7000 cGy these changes in salivary tissues are irreversible. These changes may result in substantial discomfort and interference with eating and speech. Prepubertal children do not experience these complications with similar doses of radiation suggesting that their salivary glands may be more radioresistant. (9)

Management of xerostomia in the child is similar to the adult and typically involves the use of synthetic salivary substitutes and baking soda rinses to break up the thickened viscous saliva.

LONG TERM COMPLICATIONS OF RADIATION THERAPY TO THE HEAD AND NECK

Xerostomia

As was discussed under acute reactions, permanent damage to the salivary glands may result following doses of 5000-7000 cGy. These patients invariably develop rampant dental caries which is discussed below.

Radiation induced dental caries

As mentioned earlier, radiation may permanently alter the quality and quantity of salivary flow. Saliva plays an integral role in the prevention of dental caries. Without its protective action, the cariogenic oral bacteria are permitted to colonize the teeth unchecked. In the absence of a strict and meticulous preventive hygiene regimen, rampant caries typically results. Carious lesions may begin to appear within three months of radiation therapy and proceed rapidly to devastate the dentition. The key to managing this problem is prevention. As will be discussed later, a regimen of strict oral hygiene, daily fluoride application, carbohydrate restriction and frequent dental follow up are essential.

Abnormal Development of the Dentition

Tooth development begins at four months in utero and continues until early adolescence when the permanent teeth complete their formation. As with many other tissues, radiation has the potential to interfere with normal growth and maturation of the developing dentition. The severity of malformation is dependent on the stage of development at which the teeth are irradiated and the total dose received. Abnormal development in humans has been observed with a total dose as low as 400 cGy.1 Dental abnormalities include crown and root dwarfism, root shortening, incomplete calcification, abnormal curvature of the roots, delayed or arrested eruption, and ankylosis of primary teeth. Shortened roots may lead to inadequate anchorage of the teeth in the supporting bone with subsequent loosening , increased susceptibility and involvement with periodontal disease, and early tooth loss. Ankylosis of primary teeth as well as delayed or abnormal eruption of permanent teeth may lead to significant malocclusion. These problems may require substantial efforts by the general dentist in conjunction with other specialists to restore adequate form and function to the dentition.

Abnormal Facial Development

In the same vein as disturbed dental development, the structures of the facial complex, which are also actively developing in the child, may also be adversely affected by radiation therapy. These changes are secondary to radiation effects on cartilagenous growth centers. These areas are located, for the mandible, in the condyles, and for the maxilla, in the sutural growth centers. Higher radiation doses on the order of 6000-7000 cGy are associated with disturbances of facial growth and associated malformations. The child with these growth disturbances may develop micrognathia, maxillary deficiency, retrognathia, skeletal and dental malocclusion as well as other abnormalities in the facial complex. The management of those long term survivors who manifest these complications involves a team approach involving the dentist, orthodontist, oral and maxillofacial surgeon as part of rehabilitation.

Fibrosis and Trismus

When the muscles of mastication are involved in the treatment field, radiation induced edema and fibrosis of the muscles may result. As a consequence of this fibrosis, difficulty in opening, or trismus, may occur. This, in turn, may interfere with oral hygiene, fluoride application, and dental care.

Osteoradionecrosis

Osteoradionecrosis results from the compromised blood flow to the mandible secondary to radiation induced vascular damage. This decreased blood flow impairs the normal healing capacity of the bone following even the slightest insult. It also predisposes to secondary infection of the bone. This complication of radiation therapy is rarely reported in the jaws of children and therefore will not be discussed further here. (9)

ORAL HEALTH MAINTENANCE STRATEGIES

In Pediatric Patients Receiving Radiation Therapy

Prevention is the key to minimizing morbidity secondary to radiation therapy. A carefully thought out treatment established by the radiation oncologist minimizing normal tissue exposure is the first step toward this end. A complete dental examination including radiographic exam, dental and periodontal charting, assessment of oral hygiene as well as patient and parental motivation in maintaining home care is also critical. It is imperative that all existing and potential conditions that may result in infection, hemorrhage or irritation are corrected prior to the initiation of radiation therapy. These conditions may include carious teeth, dental abscesses, periodontitis, gingivitis, and exfoliating deciduous teeth. Carious teeth should be restored if possible, otherwise extraction is warranted. Periodontitis and gingivitis should be treated by thorough cleaning of the dentition to remove plaque and calculus.

Also, of utmost importance, a comprehensive oral hygiene regimen should be established for all radiation patient's. Patients four years of age and older, along with the parents, should be instructed in proper brushing and flossing technique. It has been said that these procedures should be carried out as long as the granulocyte count remains above 5/mm3 and the platelet count above 40,0/mm3. Below these levels, these practices should be avoided to prevent hemorrhage and/or bacteremia.(9) In addition, the use of fluoride gels applied in custom made trays, daily, at home, is an important adjunct to brushing and flossing in preventing the ravages of rampant radiation induced tooth decay.

Once treatment is begun, daily evaluation of the oral cavity should be performed prior to each treatment dose. Any unusual findings or side effects of radiation should be identified and addressed either by the radiation oncologist or the patients dentist. Frequent dental follow up visits should be scheduled throughout the treatment period for the purpose of addressing complications, new dental problems, patient questions and concerns, as well as reinforcing the importance of continued home oral hygiene.

Following radiation therapy, and healing of any acute reactions, the long term effects of radiation on the oral tissues require continued frequent assessment by the dentist. Continued surveillance of the oral cavity for xerostomia, increased caries development, malformed permanent teeth, malocclusion and facial maldevelopment are all important components of the long term care of the irradiated child. The early recognition and management of these conditions may allow better corrective measures to be implemented. Also, the psychological and emotional consequences of potential facial deformity and dysfunction deserve to be addressed in these patients and proper steps taken to deal with these problems.

For the Adult Patient

How to maintain your Oral Health during your Radiation Therapy

1. Prior to radiation therapy involving the mouth or salivary glands it is imperative that you visit your dentist to determine the appropriate treatment.

2. It is recommended that all definitive dental therapy including, extractions, root canals, fillings, or crowns be completed two to three weeks in advance of your radiation treatments.

3. Radiation therapy frequently will alter your taste sensation. Often, patients complain of salty tastes and are more sensitive to hot and cold foods. However, this should return to normal in two to four months.

4. During your therapy, altered taste sensations may cause you to seek extra sweets in your diet. However, as mentioned before this can lead to increases in dental disease during a critical period, which could jeopardize your health. Do not use hard candy to remedy your dry mouth.

5. Depending on the size and dose of your radiation treatment you may suffer from a dry mouth. Initially this is difficult to tolerate , however, with frequent application of water, or artificial saliva much relief can be obtained. Talk with your dentist about options which would be right for you.

6. Many patients find themselves more susceptible to cavities, even if in the past this was not a problem. Oral hygiene must be maintained with topical fluoride to reduce the risk of disease. Your dentist will design a schedule which will meet your individual needs.

7. An increased risk of obtaining periodontal disease could pose serious consequences to the health of your remaining dentition and could result in serious infections. Again meticulous oral hygiene and antimicrobials must be used.

8. Radiation causes the mucosa or oral tissues to become irritated. You should be aware that this can be the start of an infection and you should be evaluated by your dentist or physician. Commonly, this is irritated tissues like a sunburn and can be treated by prescription mouth rinses or warm salt water rinses. It is best to avoid or dilute over-the-counter rinses at this time. They will only aggravate your tissues further. Hot or cold foods and smoking should be avoided at this time.

9. Irradiated bone, extractions or oral ulcers my lead to bone infections. It is recommended to have all dental treatment prior to radiation or at least within four weeks of completing therapy.

10. If you wear dentures please remove them from your mouth prior to going to bed. All of your soft tissues in your mouth should be cleaned every day.

11. If your gums begin to bleed while brushing or flossing, contact your dentist for an evaluation.

12. At the first sign of pain, contact your dentist, prolonging this may lead to greater problems in the future.

Possible Changes That You May See In Your Child's Mouth During Radiation Therapy

EARLY CHANGES

Mucositis: This is a reaction of the skin inside the mouth to radiation. It typically occurs within the first two weeks of treatment. Your child's mouth will become reddened and quite sore. There may even develop ulcerations throughout the mouth with severe discomfort. This reaction usually resolves completely 2-3 weeks after the cessation of therapy. The soreness of the mouth may make it difficult for your child to speak, swallow or eat. However, it is very important that your child continue to take fluid and food to maintain hydration and nutrition for proper healing. Your doctor or dentist may be able to prescribe anesthetic mouth rinses to soothe the soreness and make eating and drinking easier.

Dry Mouth: If the glands that produce saliva have been included in the area to be treated, your child may develop a dry mouth. Depending on the degree of involvement of the glands, the dry mouth may be mild to severe, and may partially return or be permanent. This too may be uncomfortable for your child and make eating difficult. It may be necessary to take frequent sips of fluids (such as water or milk) with each bite of food, as well as take smaller bites, in order to properly moisten and allow easier swallowing. There are man made saliva substitutes available that may ease the discomfort of a dry mouth and make eating and speech easier.

LATE CHANGES

Tooth Decay: Saliva is an important part of the body's mechanism for preventing tooth decay. As mentioned above, radiation therapy can cause a permanent decrease in the amount of saliva produced. This, in turn, can lead to an increased rate of tooth decay in your child's mouth. It is therefore very important to follow your dentist's recommendations on oral hygiene during radiation therapy. Brushing and flossing of the teeth to remove plaque and tartar is crucial to minimizing the risk of severe tooth decay and early tooth loss. Fluoride tooth paste should be used with a soft tooth brush. In addition, fluoride gels in custom trays supplied by your dentist should be used daily according to your dentist's recommendations. Any cavities or tooth aches should be brought to the attention of your dentist right away to avoid unnecessary loss of teeth due to decay. Finally, it is very important to keep your regularly scheduled check up appointments with your dentist so that any problems or concerns may be addressed.

Abnormal Eruption of Adult Teeth: Radiation therapy that involves the head and neck has affects on the developing adult teeth that lie within the jawbone. These affects include delayed eruption (the teeth will come into the mouth later than normal), eruption of teeth in an abnormal alignment (teeth may be crooked), or fusion of the baby teeth in the jaw bone preventing the adult teeth from erupting. These abnormalities can also be corrected, most times, with orthodontics and/or oral surgery.

Abnormal Facial Development: Radiation can also effect the areas of active growth, called growth centers, in the jaws and facial region. If these areas are in the area being treated by radiation, it is possible that future growth of the jaws and/or face may be delayed or disturbed. This altered growth may result in a small jaw with a poor bite, or an altered facial appearance later in life. However, many of the resultant deformities can be adequately corrected through a combination of orthodontic and/or oral surgical procedures.

Difficulty Opening the Mouth: The muscles that open and close the mouth may lie within the area to be treated with radiation. If so, they may be affected and undergo changes which make it difficult to open the mouth, called trismus. This may require a substantial amount of time to occur, even after treatment has stopped, and may develop gradually, making it difficult to notice. This is another reason to make sure you keep your follow up visits with your radiation oncologist and dentist even though treatment may be completed.

QUESTIONS AND CONCERNS

Finally, your doctor and dentist are there to ensure the best treatment for your child. If you have any questions or concerns regarding treatment, or side effects, do not hesitate to call them.

REFERENCES

1. National Institute of Health Consensus Development Conference Statement: Oral Complications of Cancer Therapies: Diagnosis, Prevention, and Treatment. NIH, Journal of the American Dental Association, Vol. 119, July 1989, pp. 179-184.

2. Fleming, P. Dental Management of the Pediatric Oncology Patient., Pediatric Dentistry, 1991

3. Joyston-Bechal, S. Prevention of Dental Disease Following Radiation Therapy and Chemotherapy. Int Dent Journ , 1992,42, pp. 47-53.

4. Sonis, A., Tarbell, N., Valachovic, R., Gelber,R., Schwenn,M., and Sallan,S., Dentofacial Development in Long-Term Survivors of ALL: A Comparison of Three Treatment Modalities. Cancer, 1990, 66:2645-52.

5. Wang, C.C. Radiation Therapy for Head and Neck Neoplasms: Indications, Techniques, and Results, pub 1983, Chapter 4, pp.19-21.

6. Coia,L.,Moylan,D., Introduction to Clinical Radiation Oncology, Medical Physics Publishing Company, copyright 1991,Chapter 4.

7. Marx,R., Comprehensive Review for Oral and Maxillofacial Surgeons and Residents., vol 1.,pp 17-19., University of Pennsylvania School of Dental Medicine, Aug 12-18, 1991.

8. Peterson, L., Ellis, E., Hupp,J., Tucker,M., Contemporary Oral and Maxillofacial Surgery, C.V. Mosby Company, St. Louis, 1988, chapters 14, and 18.

9. Pediatric Annals, 17 (11), November 1988, pp. 115-25.

10. Larson, D.L., Kroll, S., Jaffe, N., Serure, A., Goepfert, H., Long-Term Effects of Radiotherapy in Childhood and Adolescence, The American Journal of Surgery, 160, october 1990, pp.348-51.

11.Ruccione, Weinberg, Biologic Late Effects of Radiation Therapy, Seminars in Oncology Nursing, 5(1), February 1989, pp. 1-73.