RADIOTHERAPY AND

CHEMOTHERAPY

IN ENTDr Manpreet Singh Nanda

Associate Professor ENTMMMC&H Solan

RADIOTHERAPY IN ENT Treatment of lesion with ionizing

radiation Modes of RT External beam/ Teletherapy 90% MC Use photon (X Rays, gamma rays) and

electron beams FROM DISTANCE Skin sparing, better precision,

diminished bone absorption

Brachytherapy Uses radio active material in close contact

with lesion Types Moulds – applied to the surface of the lesion Interstitial implants – applied into tissues –

tumours of tongue and lips Intercavity implants – placed in cavity next

to the lesions – maxillary antrum, nasopharynx

As needles (radium 226, cobalt 60) or as seeds or grains ( I – 125)

Unsealed radionuclide therapy IV/oral radionuclide isotopes Spares normal tissue Eg- radioactive iodine for follicular thyroid ca Conformal radiotherapy Conforms to the size and shape of tumour Delivers max to target areas, min to

surrounding tissues and sharply cuts off critical areas

Intensity modulated RT- spares normal tissue – nasopharynx, larynx, PNS

Cyberknife stereotactic RT

RADIATION UNITS Energy deposited in unit of material Rad – radiation absorbed dose – 100

ergs deposited/gram of material Gy – gray – SI unit – 1 joule deposited/kg

of material 1 Gy = 100 rads 1 Cgy = 1 rad

TYPES Curative RT Early cancers/ small lesions To preserve function of organ Alone Benign lesions – angifibroma Dose 60-70 Gy, depend on the extent of

the lesion

Palliative RT Indications Advanced lesions where total control of

disease is not expected Distant metatasis Poor nutritional status Systemic diseases affecting heart, lung,

kidney Role To control pain, bleeding, obstruction to

airway or food passage

Adjuvant RT/Combination RT As adjuvant to surgery or CT, before or after Role To achieve better control of disease To eradicate microscopic extension of

tumour To increase survival rate in advanced lesions Types Pre op RT Post op RT Intra op RT

Pre operative RT Advantages Reduces tumour bulk and make it operable Eliminates occult metastasis in regional ln Prevent distant metastasis Blocks lymphatics, reduces chances of

dissemination of tumour during surgery Response better as oxygenation of tumour

not hampered Note – the interval between RT and

surgery < 6 weeks

Dose – 45-50 Gy Disadvantages Central part of large tumour responds

poorly to RT Reduced vitality of tissue leading to

increased chances of post op complications like delayed wound healing, flap necrosis, fistula formation and carotid blowout

Post operative RT Indications – stage III, IV Positive margins, invasion of bone or

cartilage, extracapsular invasion of ln, multiple neck nodes size > 3 cm

Within 6 weeks of surgery, dose 55-65 Gy Advantages More effective as bulk has already been

removed Lesser post op complications Can be done for residual tumours

Disadvantages Poor response to RT due to affected blood

supply Tumour cells are squeezed into blood supply

and lymphatics at the time of surgery leading to increased chances of distant metastasis

Intra operative RT At time of surgery Single large dose given to exposed tumour

bed Critical areas not included in field of RT

Fractionation schedules Normal fractionation 2Gy/ day – fraction dose 30 fractions 5 days/ week for a period of 6 weeks Total dose 60 Gy Hyperfractionation – increased number of

fractions, less dose Hypofractionation – less number of

fractions, higher dose Accelerated fractionation – shorten the

overall time

Split course fractionation RT is given in two halves with a gap of 2

weeks in between To allow acute reactions to settle Factors affecting response to RT Tumour size – small tumours better

response Tumour type – lymphoid tissue,

anaplastic – more responsive Adeno ca – radioresistant

Complications of RT Depend on site/ dose/ fractions Early Radiation sickness – loss of appetite, nausea Mucositis – stomatitis, glossitis, ulcers in oral

cavity and oropharynx, persist for 8- 12 weeks post RT

Skin reactions – erythema Pharyngeal and laryngeal oedema leading to

dysphagia and stridor Fungal infection – candidiasis Dysfunction of salivary and lacrimal glands

Late Non healing ulcer Atrophy of skin and mucosa, SMF Bone marrow depression Dental decay Recurrent infections Osteo and chondroradionecrosis (mandible >

maxilla) Malignancy – papilly thyroid ca, orbital

osteosarcoma Middle ear effusion, SNHL, vestibular symptoms Retinopathy and cataract Hypothyroidism and pituitary defect

Patient care during RT Nutrition Diet rich in proteins, vitamins, iron and

minerals NG feed, blood transfusion Avoid alcohol, tobacco, spicy food Teeth care Dental evaluation and extraction if

needed 2-3 weeks before RT to prevent osteoradionecrosis

Skin care Keep skin dry – avoid wetting or shaving Avoid exposure to sunlight Wear soft clothes Use antibiotic steroid ointment Oral care Avoid irritating mouth washes Milk of magnesia used to prevent erosion

of teeth and protect inflammatory area Xylocaine viscus to relieve pain and

discomfort

Care against infection Topical application of nystatin and

clotrimazole ointment over oral cavity and oropharynx

Protective against candida infection

CHEMOTHERAPY IN ENT Use of chemical compounds in treatment of

neoplastic diseases so as to destroy the offending ca cells without affecting the normal cells

Classification Alkylating agents – cyclophasphamide,

cisplatin (dose – 50-100 mg/m2 IV over 3 weeks), carboplatin (dose – 360 mg/m2 IV over 4 weeks)

Antimetabolites – methotrexate, 5 FU, bleomycin, mitomycin

Vinca alkaloids – vincristine, vinblastin

Taxanes – paclitaxel, docetaxel Radio active isotopes – radio active

iodine Hormones – androgen, oestrogen,

progesterone Indications To make RT more effective for primary

tumour Combined with RT for organ preservation Lesser extensive surgery To control metastatic disease

Types Palliative CT In advanced lesions or recurrence with

aim to relieve symptoms Cisplatin + 5 FU, cisplatin + mtx,

carboplatin + 5 FU, cisplatin + bleomycin, cisplatin + bleomycin + mtx

Combined modality treatment Before, during or after RT/surgery

Induction/ anterior/ NAC Before surgery or RT To reduce tumour burden, downstaging of

tumour Organ preservation – preservation of

functions of organs like swallowing, speech Increase survival rate Decrease distant metastasis Improve quality of life Response rate 60-90% after 3 cycles Complete response 20-30%, cisplatin, 5 FU,

carboplatin

Chemoradiation/ concomittant CT RT/ concurrent CT RT

Simultaneous Unresectable tumours To improve regional and local control of

disease Increases toxicity Survival rates not increased Cisplatin, 5 FU, bleomycin, mitomycin

Adjuvant or posterior RT After surgery or RT To cure micrometastasis and distant

metastasis Surgery not delayed No blurring of tumour margins Intra arterial CT In advanced salivary glands and PNS

tumours PNS – superficial temporal artery

Single agent CT 33% response Complete response 5 % Combination CT Using 2 or more drugs Not much improved survival rate though

much improved response rate Cisplatin + 5 FU – oral cavity, oropharynx,

nasopharynx, hypopharynx, larynx ca 3 cycles

Pre CT work up History and clinical exam – exclude renal,

cardiac, pulmonary disease CBC – Hb, TLC, DLC, platelets Urine exam..... RFT, LFT – cisplatin/mtx Radiology – X Ray chest, CT, MRI, USG

abdomen PFT - bleomycin ECG - adriamycin Audiometry - cisplatin

Response Complete response – no evidence of

tumour for 4 weeks Partial response – 50% tumour regression Minor response - < 50% tumour regression Stable disease – no tumour regression Progressive disease – 25% increase in

tumour growth Factors affecting response – TNM

staging, site, nodal extension, nutrition, h/o previous surgery, CT, RT

Toxicity Stomatitis, alopecia of skin Nausea, vomiting Diarrhoea Bone marrow depression, myelosuppression Nephrotoxic – mtx, cisplatin Ototoxic – cisplatin Neurotoxic – vincristine, vinblastin Cardiotoxic – adriamycin (doxorubicin) Bladder haemorrhage – cyclophosphamide Pulmonary fibrosis - bleomycin

Chemoprevention Administration of drugs which inhibit

carcinogenesis or reverse a premalignant condition

Indications – premalignant lesions, family history, high risk cases

Agents Retinoids – synthetic and natural analogues

of vitamin A Carotenoids – beta carotene, yellow skin Vitamin E Calcium, selenium, N acetyl cysteine