ABSTRACT

Oral cavity is a common site for adverse effects following RT, CT, RT &CT due to high oral mucosal turnover rates, diverse oral microbiome and trauma that can occurs in the oral tissues due to normal function. This article highlights the common oral effects during and post Radio and chemo therapy for cancers and simple interventions that can help mitigate these sequelae.

INTRODUCTION

As cancer treatments have wide range of effects on the oral tissues, a referral to a dentist can prevent several inadvertent sequelae. Reduced salivary secretions due to radiation therapy especially after treatment of head and neck cancers, and effects of chemotherapy drugs on oral mucosa have far reaching implications. Many of these patients have poor oral hygiene, gum inflammation, badly broken down and grossly decayed teeth, which are commonly associated with chronic infections which may undergo an acute exacerbation during therapy.

Pre Cancer treatment dental examinations involve a thorough clinical examination of the teeth, gingivae and supporting alveolar bone. Routine intra oral radiographs help in diagnosing decay, its extend and also help to diagnose the presence of lesions in supporting structure of teeth. Diagnostic work ups help in planning treatments which may be conservative like Root Canal treatment or dentist may schedule extractions to avoid flareups seen during RT/CT, when any surgical treatment involving the alveolar bone is best avoided.

Oral Implications in Cancer Therapy

ORAL MUCOSITIS

Oral mucositis is one of the common sequelae of cancer treatment. This has a significant impact on treatment outcomes because of its impact on quality of life, risk of infection and it is also considered as a major cancer treatment limiting toxicity. Oral mucositis may lead to cancer therapy interruption, and or changes in dose fractionation. This usually starts as an acute inflammation of oral mucosa, tongue and pharynx after cancer therapy. This may progress to a life-threatening stage with weight loss due to limited food and water intake and septic complication due to the loss of epithelial barrier.

Good oral hygiene has been found to be one of the most effective ways to lower the risk of oral mucositis. Dental visit prior to start of therapy can identify pre-existing oral pathology like dental caries, gingivitis, and or pulpal disease. Scaling and oral prophylaxis can be performed in this visit and oral hygiene maintenance measures can be taught to the patient. Other interventions include asking the patients to avoid smoking and alcohol, to minimize use of dentures, use of a soft tooth brush, have a soft diet which is low in sugar and spice, these can greatly help to alleviate the distress associated with this adverse effect.

MRONJ

Medication -related osteonecrosis of the jaws (MRONJ) is a severe adverse reaction to medicines (Bis phosphonates, denosumab and antiangiogenic agents) used in the treatment of cancer; which is primarily limited to the maxillofacial region. This has been attributed to the presence of high vascularity, rapid rate of alveolar bone turn over and remodeling due to the continuous mechanical stress to which this bone is subjected. MRONJ causes progressive destruction of bones in the mandible or the maxilla; the severity of which depends on the route of administration; with effects being lower with oral versus intravenous, dosage of the medication, comorbidities, habits such as smoking and general overall oral health and hygiene.

Dental examinations prior to start of treatment with these agents can significantly lower the chances of this potential adverse effect. These examinations help in identifying teeth which are decayed, caries involvement close to the nerve of the tooth, inflammations in the gingiva and supporting structures of teeth. MRONJ is a complication that can develop spontaneously after extractions/ Dento alveolar surgery. Hence completion of necessary elective dental procedures like extractions to root canal treatments to simple oral prophylaxis or deep cleaning of the gums will significantly help in mitigating the occurrence of this event.

In addition, patients can also be provided with information on Anti -Resorptive, Anti- Angiogenic therapy risks, and counselled on the importance of maintenance of good oral hygiene, regular use of an anti-bacterial mouthwash and the benefits of limitation/ cessation of smoking and alcohol.

Xerostomia & Radiation Caries

Xerostomia/ dry mouth is a common complication following radiotherapy to the head and neck region for cancers. RT has a multitude of effects in the oral milieu. There is an alteration in the composition, volume, buffering capacity, pH of saliva and change in the oral microbial flora leading to a more acidogenic (acid producing) and cariogenic (decay promoting) environment.

Xerostomia can be reduced in these patients by using salivary sparing RT Cytoprotective agents like Amifostine which accumulates in the salivary glands and acts as a free radical scavenger. Salivary substitutes like Biotene mouth spray, sialagogues like oral pilocarpine, use of lemon candy and sugar free gums can help in stimulating salivary flow.

Radiation caries is one of the earliest problems seen post RT, CT. This a rapid, rampant decay primarily affecting the neck (Cervical) and biting (Incisal) surfaces of the teeth. These can rapidly involve the pulp/nerves of the tooth structure resulting in severe pain. Radiation caries is attributed to decreased salivary flow and to direct radiogenic damage to structure of teeth. Endodontic therapy is the treatment of choice, for deep decays, as extractions are best avoided as much as possible to reduce risk of osteoradionecrosis. Follow up dental appointments are insisted for meticulous maintenance of oral hygiene.

In conclusion, dentist visit prior to start of therapy can help in identifying and preventing several oral issues which commonly arise during cancer therapy. Teeth can be effectively treated and secured to prevent any inadvertent complications that may result in delay/ discontinuation of cancer therapy.

Patients can be motivated to maintain good oral hygiene by teaching them correct brushing techniques, use anti- cavity fluoride based mouth washes, can be provided with prophylactic topical fluoride treatments, diet counselling, use of artificial salivary substitutes. These are simple effective interventions to reduce several adverse events that may occur following cancer therapy.

Dr. Preeti L. Anand
Senior Dental Surgeon & Implantologist
Kauvery Hospital Chennai