While focusing on overcoming and surviving cancer, few may take a moment to consider the effects of the treatments needed to eliminate the malignancy. Unlike conventional medications, the body does not flush radiation. Radiation levels also accumulate with each treatment. Depending on the number and intensity of treatments, cancer patients are at risk for various long-term effects.
Radiation Doses
Radiation exposure is measured in millisieverts or mSv. A typical X-ray emits approximately 0.1mSv to 8mSv, and a mammogram emits 3mSv. The dose emitted during a full-body CT scan is around 10mSv. Nuclear facility workers are limited to 20mSv of exposure annually. These levels are considered tolerable, present no immediate symptoms and do not pose a risk of developing cancer. Doses between 100mSv and 1,000mSv may not cause immediate symptoms. However, there is a pronounced increase in the risk of developing cancer later in life.
Medical Radiation Doses
Doses higher than 1,000mSv present an ever increasing risk of developing radiation sickness and cancer. Millisieverts can be compared to medical radiation doses. Medical radiation treatments are measured in Grays or centiGrays. Ten mSv are equal to 0.10 centiGrays. During treatment for breast cancer, for example, over a five-week period a woman may become exposed to as much as 5,000 centiGrays or 50,000mSv. The increased exposure levels present a high risk of developing secondary cancers anywhere from 5 to 15 years later.
Long-Term Damage
The type of radiation damage depends on what part of the body was targeted for treatments.
• Central nervous system-Radiation therapy exposure to the brain, spinal cord or peripheral nerves may lead to an increased risk of developing a stroke, a brain tumor or various types of nerve malfunction.
• Endocrine system-Radiation to the head or neck region may adversely affect the thyroid gland and cause hypothyroidism. Pelvic treatments may cause early onset menopause in women.
• Cardiac problems-Exposing the chest to radiation therapy may lead to irregular heart rates, coronary artery disease or congestive heart failure.
• Respiratory damage-Chest area radiation may cause inflammation and irritation of the lungs. Patients then experience difficulty breathing. Irritation leads to lung lining thickening and lung expansion interference.
• Gastrointestinal system-Abdominal treatments may cause tissue scarring. The stomach and intestines may have difficulty properly breaking down food and absorbing nutrients. Patients may also develop chronic diarrhea and have constant pain.
• Genitourinary and reproductive systems-Abdominal, back or pelvic radiation treatments may cause permanent damage of the kidneys, bladder, ovaries, uterus, testicles or in the connective tissues. Patients may suffer problems filtering, holding and eliminating urine or become infertile.
• Blood cell production-When the bones responsible for creating bone marrow stem cells endure radiation exposure, the immature cells may die, not mature properly or grow abnormally. The blood then becomes deficient in certain components, which is a type of blood cancer known as myelodysplasia.
