Management of common radiotherapy side effects

Published on 09/04/2015 by admin

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24 Management of common radiotherapy side effects

TV. Ajithkumar

General side effects

Skin

Radiation dermatitis generally starts 10–14 days after the first fraction of radiotherapy and peaks at the end or within one week of completion of radical treatment. It progresses from skin erythema, to dry desquamation (dry, itchy, flaky), moist desquamation (raw painful area which may drain serous exudates) and finally necrosis (rare). Skin reaction is intense when skin dose is high (e.g. electrons, bolus over the field), over areas with skin folds (e.g. inframammary fold, groin, perineum etc.), when radiotherapy is given concurrently with chemotherapy (particularly with anthracyclines, methotrexate, and 5-fluorouracil) and over areas of surgical wounds.

Measures to minimize skin reaction include avoiding mechanical, chemical and thermal irritations such as pat drying rather than rubbing, using simple soap, avoiding perfumes, powders, deodorants over the irradiated area, shaving with razor blade, heat, cold and sun and using loose fitting and cotton clothes. 1% hydrocortisone cream is useful for itchy areas.

During dry desquamation, hydrophilic moisturizing ointment with no heavy metals (e.g. aqueous cream) can be applied to the skin after radiation treatment every day. For moist desquamation, dress the moist area with hydrogel, hydrocolloid or alignate dressing and continue applying aqueous cream to other areas. When radiotherapy is stopped, zinc oxide or silver sulfadiazine (flamazine) may be applied to the skin with non-adhesive dressing. Superadded infection may need antibiotics depending on culture and sensitivity.

Radiation reaction heals in 3–4 weeks followed by tanning of the skin which takes a few more days to subside. Patients are asked to protect irradiated skin with sun block when sun exposure is unavoidable.

Late skin reactions include atrophy and fibrosis of skin and telangiectasia. Radiation recall is the phenomenon of skin reaction occurring in the previous radiation field when exposed to certain chemotherapy (e.g. anthracyclines and gemcitabine). This is usually more severe than previous radiation reaction and subsides in 2 weeks.

Fatigue

Fatigue (a subjective feeling of tiredness) is a common side effect of radiotherapy and the exact cause is not known. Fatigue may increase progressively during the radiotherapy and may take weeks or months to subside after radiotherapy treatment. Measures to improve fatigue include frequent periods of rest, regular minimal aerobic exercise, and stress management. A study showed that 20–30 minutes of brisk walking 4–5 times per week improved fatigue level, symptom intensity and physical functioning.

Anorexia

Some patients experience anorexia and the exact cause is not known. A number of factors such as the primary cancer itself and its systemic treatment as well as concurrent medications can influence the degree of anorexia. Measures to improve anorexia include frequent small meals, high energy high protein diet, and sometimes appetite stimulants like megestrol acetate (400–800 mg daily) or steroids. Anorexia can cause clinically significant weight loss (loss of ≥10% prediagnosis weight loss) in which case enteral feeding is advised, particularly to those receiving radical radiotherapy.

Bone marrow suppression

Irradiation of a large area of marrow bearing bones can result in bone marrow suppression. The degree of bone marrow suppression is high if concurrent myelosuppressive chemotherapy is used. All patients at risk of bone marrow suppression need weekly blood counts and appropriate action.

Site-specific side effects

Brain

Cerebral oedema

Radiotherapy can cause cerebral oedema which manifests as headache, vomiting, seizures, neurological deficit and altered mental function. Steroids are the treatment of choice.

Alopecia

Alopecia depends on the dose and extent of radiation. Alopecia starts when the radiation dose is above 25–30 Gy and is permanent when the dose is >40 Gy. If regrowth occurs it usually starts 2–3 months after completion of radiotherapy.

Head and neck cancer

Mucositis

The initial reaction is tenderness in the mouth with associated erythema and oedema of the mucosa. Subsequently a whitish membrane is formed, which progresses to a painful ulcer with continuation of radiotherapy. Bleeding and superadded infection can occur. Concurrent chemotherapy and metallic fillings in teeth (by electron back scatter) can enhance mucosal skin reaction. Dental assessment prior to radiotherapy is important (p. 79). Measures to prevent and manage mucositis include:

• Radiotherapy planning – use of midline radiation blocks wherever appropriate and 3D planning reduce mucosal injury.
• Mouth care – frequent cleansing, tooth sponges and swabbing rather than use of a toothbrush.

• Mouth wash – sterile water, 0.9% saline or sodium bicarbonate solutions. Normal saline can be prepared by adding one teaspoon of salt to 1 litre of water and 1–2 tablespoons of sodium bicarbonate can be added if the saliva is viscous.
• Benzydamine (Difflam) is recommended for prevention of oral mucositis whereas chlorhexidine, sucralfate and antimicrobial lozenges are not.

• Pain – controlled by topical anaesthetics and analgesics and systemic analgesics.
• Diet – soft bland diet and in severe mucositis, enteral feeding.

Xerostomia

During radiotherapy, dry mouth starts within 1–2 weeks of radiotherapy which involves the region of salivary glands. Later saliva becomes thick and sticky which causes problems of retching, coughing, nausea and vomiting, difficulty in talking and disturbed sleep. Dry mouth can become chronic. Measures include:

• Mouth care – frequent cleansing.
• Improve moisture – frequent sips of fluids and saliva substitutes.
• Stimulate saliva – sucking candies, pharmacological measures (e.g. oral pilocarpine 5 mg 3–4 times daily).
• In suitable patients, intensity modulated radiotherapy (IMRT) delivery (p. 85) can avoid irradiation of at least one salivary gland and thereby reduce the degree of xerostomia.

Taste change

Radiation can change taste sensation, which may persist for years. It usually starts after doses >20 Gy and around 90% patients receiving radical radiotherapy are affected. Measures include mouth care before and after meals and modification of food and preparation. An unpleasant taste of meat is one of the common problems, which can be masked by trying additional seasoning, marinating meat in wine or sweet and sour sauce before and during cooking and serving food cold or at room temperature.

Hypopituitarism and hypothyroidism

Patients who received radiotherapy to the pituitary and thyroid regions are at risk of hormonal insufficiency. Patients need hormone replacement treatment.

Thoracic region

Cough

Cough is initially productive which becomes dry as treatment progresses. Treatment is symptomatic with adequate fluid intake, humidification of air, cessation of smoking, cough suppressants and antibiotics if there is superadded infection.

Pneumonitis

Acute pneumonitis usually occurs 1–3 months after radiotherapy and rarely earlier (‘hyperacute’). It manifests initially with dry cough and later with productive cough, fever and dyspnoea. Treatment includes bed rest, steroids (prednisolone 1 mg/kg for 4–6 weeks) and antibiotics if superadded infection.

Oesophagitis

Oesophagitis develops 2–3 weeks after starting radiotherapy and the severity is high with concurrent chemotherapy, long length of oesophagus in the radiation field and increased dose per fraction. Patients develop progressive painful swallowing. Measures to improve dysphagia include liquid high calorie, high protein diet, local anaesthetics, liquid analgesics and systemic analgesics. Patients may develop superadded candidiasis and need antifungal treatment.

Radiation fibrosis

Radiation fibrosis develops 6–12 months after completion of radiotherapy and can manifest with dyspnoea. Treatment is essentially symptomatic.

Abdomen and pelvis

Vomiting

Vomiting is common with radiation involving the upper abdomen. Vomiting can occur within 6 hours of radiotherapy and may last for 3–6 hours. Patients receiving treatment to the upper abdomen, large single fractions and total body or lower hemibody irradiation are advised to have prophylactic anti-emetics with a serotonin receptor antagonist (e.g. ondansetron 8 mg, 30 minutes prior to radiotherapy). In severe vomiting continual administration of antiemetics is needed. Dietary modifications with low fat, low sugar diet and high fluid intake are also useful.

Diarrhoea

Diarrhoea can occur 2–3 weeks after starting treatment. The pattern of diarrhoea may be either increased frequency of stool or watery stools with abdominal cramps. Sulfasalazine 500 mg twice orally is suggested to reduce the incidence and severity of radiation-induced enteropathy in patients receiving pelvic radiotherapy. A low-residue, low fat (<40 g) diet and avoidance of milk products can be useful in reducing diarrhoea. Antidiarrhoeal medications such as codeine and loperamide are useful when dietary modifications are ineffective.

Proctitis

Patients with tenesmus benefit from antispasmodics and anticholinergics. Pain can be controlled by frequent sitz baths and local creams such as haemorrhoidal preparations. Patients with chronic proctitis are treated with sucralfate enema.

Cystitis

Cystitis manifests with dysuria, nocturia, urgency, hesitancy and frequency. Patients are encouraged to have an adequate fluid intake. Bladder infection should be treated. Bladder analgesics (e.g. phenazopyridine) and antispasmodics are useful in pain. Patients receiving prostatic radiotherapy can develop bladder outflow irritation which manifests with hesitancy, decreased force of flow and frequency. In these situations, alpha blockers such as terazocin (Hydrin) and tamsulosin (Flomax) result in better symptom control than NSAIDs.

Vaginal stenosis and dryness

Vaginal stenosis and dryness are late effects. Treatment is symptomatic with lubricants and vaginal dilatators.

Erectile dysfunction

Erectile dysfunction results from damage of pelvic nerves and fibrosis of pelvic vasculature. Pharmacological interventions, devices and prosthesis are useful.

Gonadal failure

Ovarian failure can induce symptoms of menopause and permanent sterility (>8 Gy fractionated dose). HRT is useful if not contraindicated. In young people needing pelvic radiotherapy, laparoscopic oophoropexy (surgically placing ovaries outside radiation field), may be protective.

Testicular irradiation (>12 Gy of fractionated RT) causes permanent sterility and hence if appropriate the testes should be shielded from radiation.

Further reading

Faithfull S, Wells M, editors. Supportive Care in Radiotherapy. Edinburgh: Churchill Livingstone, 2004.

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