Management Head and Neck Cancer Edited

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Radiotherapy

Implications for dentistry

Adapted from source

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Surgery

Cytotoxic chemotherapy Radiotherapy

Effects of radiotherapy on oral structures andmanagement of those effects

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Cure ² eradication of all cancer

Benefit ² long term survival

Some long term side effects are acceptable

Palliation ² alleviate effects of cancer eg relieve pain, shrink cancer with chemotherapy

Benefit - modest

Side effects of treatment should be slight

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10090

80

70

60

5040

30

20

10

0

% S

U R V I V A L

12 24 36 48 60

MONTHS

85% (461-234) S1

95% CIS1 461 419 363 316 267 234 82, 88[ ]

75% (575-249) S2

95% CI

S2 575 502 427 361 308 249 72, 79[ ]

67% (2142-777) All

95% CI

All 2142 1673 1326 1108 935 777 64, 68[ ]

65% (346-122) S3

95% CI

S3l 346 266 211 175 147 122 59, 70[ ]

45% (701-157) S4

95% CI Median

S4l 701 440 289 227 191 157 40, 49[ ] 36 Mths

Oral Cavity 1970-2005 : Overall stage

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Anticancer drugs given by iv injection as a course,either weekly or every 3 weeks over about 4 months

Acute effects Nausea, vomiting

Mucositis, mouth and lip ulcers Bone marrow suppression ² thrombocytopenia, neutropenia

(may be severe), hence increased risk of infection

Late effects uncommon except after leukemia chemo Used to treat cancers of breast, bowel, lung,

lymphoma, head and neck If an invasive dental procedure is needed duringchemotherapy check FBC and discuss with theoncology team



X-rays are part of the electromagnetic spectrumbeyond UV

Low dose used for diagnostic x-rays

Very high dose radiation produces tissueeffects

Radiotherapy uses very high energy x-rays to

very high dose (shielding treatment room 1mthick concrete)

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Treatment machine ² linear accelerator

May use multiple beams of various shapes

RT course ² daily, 5 days per week for 6-7weeks

Sometimes cytotoxic chemotherapy is added,concurrent with radiotherapy, does increase

cure rates but increased toxicity

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Can cover a wider volume than surgery

For head and neck cancer, RT is used as analternative to surgery or as supplementary

treatment with surgery where surgery would produce functional defect, eg

early larynx tumours, nasopharynx, posterior tongue

where surgery unlikely to be curative

where surgery likely to leave microscopic disease Oral cancer ² surgery preferred to RT

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Design radiation target volume to coverprimary plus regional nodes Design dose radiation according to bulk of

tumour at various sites. eg macroscopic disease - high dose, microscopic disease - lower dose

If a well lateral tumour then designradiotherapy volume to treat unilateralstructures avoiding high dose to contralateral

structures Fractionation of radiotherapy ² multiple

smaller fractions gives less late side effects thanshorter courses

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PTV 60Gy PTV 70Gy



Loss of taste

Xerostomia

Mucositis

Oral thrush

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Hyposalivation ² xerostomia.

Lack of taste

Atrophy mucosa

Atrophy of alveolus ² delay fitting denturesuntil 6-12 months after RT

Dental caries, may be severe

Osteoradionecrosis of the mandible Trismus

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Hyposalivation - decreased saliva. Sometimessymptoms of xerostomia improve a little overtime.

Increased viscosity Acid saliva, from the normal pH 7 down to pH

5

Altered oral flora with increase acidogenic and

cariogenic organisms (Streptococcus mutans,Lactobaccillus, Candida)

Altered electrolytes, effect remineralisation ofdentine

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Hypersensitivity of teeth initially Decreased remineralisation Increased caries, which may be severe, rapid

onset, painless Caries may have a different pattern to usual, on

labial surfaces at dentin-enamel junction, andmay include mandibular anterior teeth

Black brown discoloration of entire tooth

crown Dentin microhardness effected, enamel chips

break off

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Maxillofacial surgeon assessment prior to radiotherapy Poor teeth extracted prior to RT Good teeth preserved in moderate dose region Molars in the high radiation dose region may be

extracted with alveoplasty and healing prior to RT

Neutral tooth paste Bicarbonate mouth washes Chlorhexidine mouth wash Fluoride gel applications daily to help mineralisation

long term Frequent dental assessment

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Osteoradionecrosis of mandible

Factors

high radiation dose

trauma

infection

Avoid trauma to area of mandible that hasreceived very high radiation dose

Get information on radiation dose prior to dentalextraction

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High activity bisphosphonates

Zoldronate

Pamidronate

Above drugs mainly used for myeloma and breastcancer

Sclerosis of bone

Trauma may precipitate osteonecrosis



Minor ² small area of ulceration of mucosa over

alveolus with exposure of superficial mandible.Sometimes small spicules of bone can be extruded. Avoid trauma eg from dentures rubbing mandible Treat any sharp areas causing abrasion Tetracycline H

yperbaric oxygen Major ² deep area of necrosis, infection

This is a major problem, difficult to treat Management by a Maxillofacial surgeon Drain abscess Debride necrotic tissue (caution: trauma can exacerbate

osteoradionecrosis) High dose broad spectrum antibiotics (infectious disease

specialist) Hyperbaric oxygen

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Results of treatment of head and neck cancerusually good

Chemotherapy effects are acute

Radiotherapy important treatment method Radiotherapy to mouth has significant long

term side effects on saliva, teeth and mandible

As the results of treatment improve, it is

possible more dentists will come in contactwith patients who are having chemotherapy orwho have previously had radiotherapy

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Kielbassa AJ et al. Radiation-related damage todentition.

Lancet Oncology 2006;7:326-35.

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Management Head and Neck Cancer Edited

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