Radiation Therapy Side Effects
The following are the most common side effects, both acute and chronic, resulting from radiation. Unforeseen side effects may occur because of the unique and varied tolerance of individual persons. Late effects of treatment may not always be predictable and may be influenced by concurrent and/or subsequent treatment for this and other diseases. These common side effects include, but may not be limited to the following.
Radiation treatment to the brain is given for a variety of conditions. These treatments typically last for a total of 2 to 7 weeks and may be administered once per day or twice per day, five days per week. The radiation therapy of central nervous system tumors is precise and technically elaborate. In addition to conventional external beam radiotherapy, some patients may be candidates for implanted radiotherapy or stereotactic radiosurgery. These methods will be discussed with you if appropriate. Most patients will experience at least some of the side effects listed below.
Many patients experience fatigue which starts during the second or third week and progresses as the treatment progresses. This typically subsides gradually over 2 to 6 weeks following the radiation treatment. This is not normally debilitating and, in itself, should not affect your daily activities or ability to drive. However, you may wish to go to bed earlier or take an afternoon nap during this period. Fatigue and weakness are worse in patients who lose weight. Accordingly, we strongly encourage you to supplement your diet with high calorie foods or commercially available nutritional supplements (for example Ensure Plus, Sustacal, Boost), if necessary to maintain your weight.
Your blood counts may require monitoring periodically during treatment, especially if you also receive chemotherapy.
Hair loss usually occurs within the treated area 2 to 4 weeks after the treatment starts. If the whole brain is treated, then essentially all of the hair will be lost. If only part of the brain is treated, then the hair loss pattern may be more geographic with some areas remaining normal while adjacent areas lose the hair. Regrowth of the hair usually follows 3 to 6 months after radiation therapy, although will be incomplete in some patients. In rare patients, hair in the treated area will not regrow at all.
Skin reaction, resembling a sunburn, often occurs in the same areas where the hair falls out, reaching its maximum during the final week of treatment as well as the first week afterward. There are a variety of topical measures used to alleviate this condition.
The radiation will pass through the ears in many patients, causing irritation in the external canals of the ears where wax and/or excess skin may build up and even temporarily interfere with hearing. Long-term hearing complications are extremely unusual. Prescription or over-the-counter remedies may be prescribed by your physician to alleviate this temporary condition.
If the radiation beam passes through any part of the eyes, then some patients will experience irritative symptoms such as tearing and/or redness. This is expected to be a temporary condition which may respond to topical solutions recommended by your physician. In rare patients, visual complications ranging from cataracts to more catastrophic complications may occur. These are unusual. The incidence of a major visual injury is well under 1%.
Some patients get a dull headache and/or pressure sensation in the head as the treatment series evolves. This is caused by swelling around the tumor and will typically respond to Decadron (dexamethasone). Your physician and staff will work closely with you during the treatment course to try to optimize the dose of that medication. Most, although not all of our patients with central nervous system tumors, will be taking dexamethasone during their treatment. There is a fine balancing act between minimizing dexamethasone side effects vs minimizing pressure in the head caused by swelling around the tumor. You should never change your dexamethasone dose without first consulting with your treating physician.
Nausea and vomiting are unusual with radiation to the head unless there is a significant amount of swelling and pressure in the head. This would typically be treated by starting or raising the dose of dexamethasone. Dexamethasone may also have effects on the gastrointestinal tract, including ulcers, such that we would generally advise that dexamethasone be taken with antacids or anti-ulcer medications. Your physician will individualize this recommendation as warranted by the specifics of your case.
On rare occasions, patients may have serious delayed complications of radiotherapy but, with modern techniques, these are most unusual. Some patients may also have subtle difficulties with thought processes after radiation therapy to the brain, but this is usually not enough to interfere with activities of daily living. This may be a greater issue for young pediatric patients and will be discussed between patient, family and physician on an individualized basis in great detail where appropriate.
There are additional concerns regarding pediatric patients who receive radiation therapy to the brain. In addition to the greater propensity for intellectual decrease, there may be injury to the pituitary gland which could result in disturbances such as decreased growth hormone production, with short stature. Pituitary injuries are rare in adults. This will be discussed in greater detail between patient, family and physician as appropriate, at the time of consultation.
You may also notice permanent subtle changes in the treated area including the skin. Inexpensive moisturizing lotion or aloe vera gel is recommended for local dryness or itchiness. The treated skin may be more sensitive to sun exposure. Accordingly, we advise wearing clothing or sunscreen over the treated area while spending time outdoors. This is a lifelong recommendation.
This statement is not a warranty, but it is simply meant to give information regarding typical radiotherapy side effects and their management. Catastrophic or even fatal radiation complications may occur in rare cases. Great care will be taken to minimize the side effects and reduce the risk of radiation damage to normal tissues.
For more information see: CyberKnife Centers of San Diego- Intracranial Lesions
