There is a scale of radiosensitivity of cells ranging from highly sensitive to relatively insensitive. The former are easily affected by low doses and the latter are able to tolerate higher doses of radiation. A direct relationship exists between the radiosensitivity of cells and the rate of growth.
Sensitive group–cells that are rapidly dividing
Less sensitive group
The skin is irradiated in all treatments for external beam therapy as it is the portal though which radiation enters the body irrespective of its involvement.
In superficial treatments, the skin reaction is the limiting factor, since the maximum dose is absorbed in the superficial layers.
This is a cumulative effect and therefore is not apparent during the first 7 to 10 days of treatment. It should be noted that the skin dose with megavoltage energy range is considerably less than at the superficial energy ranges, since the maximum dose is built up at a depth below the skin (dependent on the beam energy). This does not however mean that patients treated with megavoltage energies do not have skin reactions.
Skin reactions resulting from megavoltage treatment may be due to:
Skin sensitivity is expressed in the same way as reactions to ultra-violet rays (sunburn). Persons with fair skin tend to be more sensitive than darker persons and the changes are easily visible. Sensitivity of skin folds e.g. armpits, knee and thigh folds is higher and hence reactions occur earlier and last longer in these areas. Moisture due to sweating also contributes to quicker reactions. Wearing loose cotton clothes and keeping the skin folds dry is helpful.
May be considered as acute or chronic
Acute Dermatitis occurs in four stages:
1. First degree. The skin becomes itchy with increasing reddening (erythema). The basal cells in the epidermis are the rapidly dividing cells that are damaged. The reactions of the skin is due the inflammation that results due to the breakdown of damaged cells. Emollient steroid creams and/or antibiotic ointments may be needed and will be prescribed to you by the doctor.
2. Second degree. This is the epilation dose. Damage is cause to hair follicles. Hairs become loose and fall out spontaneously. Regrowth occurs 2-3 months following completion of treatment. The sweat glands and sebaceous glands are damaged resulting in dry and itchy skin. The dryness progresses to flaking and peeling (dry desquamation). The treating physician will be able to help you with topical creams. The hair falls only if directly exposed to radiation e.g. in brain radiation.
3. Third degree. The erythema deepens with the formation of blistering. The skin breaks down with the exudation of serum (moist desquamation). Damage to hair follicles and sweat glands are permanent if the radiation has been given to this dose.
4. Fourth degree. This is not normally seen, and due on the whole is to over dosage of the skin. The blistering and skin damage involves the deeper layers of the skin (necrosis). The lesions are painful, taking several months to heal due to destruction of blood vessels.
Most of these reactions are seen less often due to increasing use of megavoltage units. These reactions would tend to occur a few months following completion of treatment.
Pigmentation– Colouration varies from light to dark brown and often depicts the shape of the treatment field.
Atrophy – After healing from moist desquamation, the skin is altered in texture and colour. The skin may be darker with a papery covering that readily breaks down.
Ulceration – Persistent break down of an atrophic area that may be slow or fail to heal. Excision grafting may be required.
Telangiectasia – Destruction or narrowing of small superficial blood vessels, it leads to compensation by capillary dialatation. Skin appearance is a network of broken superficial veins.
Ischaemia – The destruction and damage of blood vessels leads to depleted blood supply and gradual tissue destruction.
Thickening – Damaged skin may heal with loss of elasticity giving it a typical leathery feel (fibrosis).
Explanation – Simple explanation at the start of treatment of typical reactions the patient is likely to expect (dependent on treatment site) will go a long way in taking care of the reactions. Most patients are not very receptive on the first day of treatment, therefore explanations usually need repeating.
Advice – Patients need information on how to care for the skin being irradiated. Depending on the area being treated, the patient may also require more specific advice.
Hot water should not be used on the skin area being irradiated. Friction due to any abrasive material must also be avoided. Daily bath or shower is important for all patient (especially for patient who are having pelvic irradiation), to reduce the risk of infection.
Patient who perspire profusely are encouraged not to use deodorant under the arm being treated (breast fields).Every patient should have a water bath and also use a mild soap if there are no skin marking e.g the patients wearing an immobilization cast (which bears the area marking for treatment). Others can have only shower and the marking can re-marked by the technician if they get lighter. Please do not mark yourself.
Electric shaving may be done until such time as the skin becomes too tender for this to continue. Avoid after shave lotions, oils or creams as they may cause itching and skin breakdown.
Friction must be avoided at all cost. The skin should be patted dry with a soft towel. Baby talcum powder may be sparingly used on the skin. Most powders contain zinc oxide which tend to adhere to the skin, giving rise to secondary reaction, causing an increased skin reaction when irradiated. Excessive use will increase dryness of the skin. Talcum powder should not be used in the skin folds, especially once the skin has broken down. This will make the area difficult to clean and lead to infection.
Irritating or unpleasant erythema can be soothed with: 1% hydrocortisone ointment. Moist and discharging skin should be cleaned daily and kept dry. Application of Silver sulphadiazine ointment and/or a disinfectant emollient helps overcome the pain, itching and prevents infection.
Non-adherent dressing e.g. Sofratulle or paraffin gauze is helpful in dressing the broken down skin surfaces and promote healing.
The oral cavity is a site where complications frequently develop either as the direct result to the malignancy or as an unwanted side effect of the treatment. Most of patients experience severe difficulties in mastication (chewing) following major head and neck surgery (with implications for normal social adaptation), so time must be made available during the pre treatment phase for a dental assessment and realistic oral hygiene instruction.
The Dental Hygienist can provide simple preventive advice to the patient and at the same time emphasize its value in maintaining oral comfort during therapy. Smoking cessation is recommended during radiotherapy as smoking exacerbates inflammation of the oral soft tissues.
Along with the assistance of the dietician, detailed dietary advice can be provided. A high calorific intake is required during radiotherapy. This usually translates into an increased and frequent consumption of refined carbohydrates and in turn encourages the incidence of dental caries (tooth decay). To combat this, those patients receiving radiotherapy need to use a daily fluoride mouthwash to prevent dental caries and promote enamel remineralisation. If the teeth need extraction or filling, it should be done prior to starting treatment.
Radiation also can cause the death of the rapidly dividing epithelial cells and the integrity of the mucosal epithelium is lost after the first 12 days of treatment. Normal daily tooth brushing by the patient is reinforced and if necessary a soft, baby’s brush can be used. Oral hygiene practices are supplemented with the use of a chlorohexidine gluconate mouthwash or gel. It is necessary to avoid strong tooth pastes, hard, spicy and acidic foods, alcohol, tobacco, fizzy drinks and sweets as these may traumatize and irritate the gums.
A further effect of radiotherapy, depending on dosage, is the reduction or cessation of saliva production. This affects swallowing, chewing and speaking. The mouth washes with a pinch of baking soda and common salt in half cup of water help keeping the oral cavity clean.
Every effort is made to reduce the effect of xerostomia (dry mouth). The symptoms of xerostomia can be helped by:
Oral care cannot prevent radiation induced changes, but it is vital in preventing additional infections that can cause further damage and pain. Following treatment, as taste returns, patients often seek comfort in sweet foods and drinks. However, meticulous oral hygiene and dental care during radiation will help the mucosal surface return to their normal healthy state in period of 12-18 weeks. If there is foul smell or fever, addition of antibiotics after culture sensitivity helps combat bacterial infections.
Tiredness or Fatigue
Many patients may feel tired while undergoing radiation therapy. Various factors are contributory to this state, like, low intake of food, disruption of sleep and rest, lack of activity, stress, anxiety, depression, daily visits to hospital and prolonged treatment. Here are some hints to try to feel less tired:
Patients undergoing radiotherapy may have temperature upto 100F for upto 2 hours after irradiation. But if the fever persists throughout the day do see your consultant, it may be an infective fever.
A tablet of paracetamol may help overcome the sense of body aches accompanying this fever and is safe to take with other medicines.
Patients undergoing Brain Irradiation
Radiation affects the membranes of mouth and throat. Starting from 3rd week of radiation there will be discomfort while swallowing, altered taste sensation, nausea, ulcers in mouth, thick saliva and hoarseness of voice.
To overcome these side-effects oral medications are prescribed (may require short term hospitalization if the severity is more)
Patient should follow these recommendations:
Undergoing Breast irradiation
Radiation effects form radiation therapy to the breast usually include some degree of skin redness that is usually mild and does not cause symptoms, usually there are no other significant side effects of radiation therapy to this site. The skin reactions resolve in a few weeks and long term adverse cosmetic results attributable to radiation therapy are infrequent.
Lung and esophagus (the tube through which food is swallowed) cancers are the most common cancers where radiation therapy is delivered to the chest. After 2-3 weeks, patient may complain of discomfort in swallowing. If this happens, special dietary instructions need to be given. Your doctor will give you medicines to ease this discomfort; please see him/her.
Cough and fever, during or after completion of radiotherapy, happen due to infection and one should report it to the consultant at the earliest, rather than taking cough medicines from local doctor.
A part of the small intestines, large intestines or bladder may get a part of the radiation dose due to its close proximity to the tumour. The side effects which a patient may have after 2-3 weeks of starting radiotherapy are:
There are medicines available for the above symptoms and will be prescribed by the doctor as and when required.
The patients should follow these tips:
Unless you are a diabetic, have hypertension or renal problem, you are advised to take a good nutritious diet consisting of fresh fruits, yogurts, milk products, vegetables, cereals, pulses, chicken, eggs, fish, fruit juice and plenty of water. Hot tea, hot coffee and carbonated drinks intake should be limited to a low amount.
A diet of 2500-3000 k calories with 80-100 gram proteins per day is recommended for an average adult. In case you have diabetes, a special diet should be worked out, along with the dietician, to meet your requirement. For hypertensive and renal disease patients a nephrology consult may be required.
Radiation treatment and daily visits to hospital are stressful to certain patients. It is recommended that a healthy diet should be taken to prevent infections and breaks in the treatment. The patients and their family’s co-operation in this feature is of utmost importance.
Some patients may feel depressed and develop lack of sleep during this treatment. The contributing factors may be a long treatment, daily visits to the hospital, long leave from office/work, not enough inputs for intellectual/physical stimulation, economic hardships, loneliness, reduced social contact; fear of permanent disability and recovery to mainstream.
It is best that you openly discuss your fears and concerns with your doctor. He/She may help you with some suggestions, talk to your family members, help you with medication or set up an appointment with the expert who can look after physical symptom causing this problem due to pain/frequent urination at night/loss of appetite.
Your are encouraged to take up your routine activities during the course of radiation, as they will help you get through the day and add meaning to the day.
Unless you are on sedatives or are undergoing brain irradiation, driving can be done. Over exertion, crowded places, family members with acute infections are avoidable to prevent getting infection yourself.
Radiation therapy deploys the principle of differential division of tumour cells and inability to recover from radiation effects versus the normal body tissue ability to recover in a specified time. If you miss or try to avoid treatment to overcome the side-effects of treatment; along with the normal tissue the tumour may start regrowing. Hence it is recommended that there should be no breaks in the treatment. You may need extra care and /or hospitalization to overcome the side effects, but please DO NOT MISS your treatment without discussing with your doctor.
It may take from 3-6 weeks for overcoming the side effects and complete recovery after the completion of treatment. If required, do take an appointment during recovery, to see you doctor.
You will be given medicine and advice at the time of discharge, to help in the recovery process. Some side-effects may take longer especially if radiation was given after surgery and/or Chemotherapy.
A regular follow up with/without investigations at an internal of 2-3 months for the first two years is recommended. There after the follow up intervals may be prolonged depending upon the disease status.
Note : Radiation therapy is an integral part in the management of many cancers. The improved methods of planning and radiation delivery over the last few years have helped us reduce the side-effects; however side-effects are an essential accompaniment to the treatment. At present it must be understood that most of the acute effects are reversible over time and radiation can be taken fully with co-operation from family and medical staff.