By Carol L. Kornmehl, M.D. May 11, 2006, 21:25 GMT
Why is radiation therapy so stigmatized? After all, it is a very useful treatment and its benefits far outweigh its risks. How can a modality that cures cancer and spares people from mutilating cancer surgery, such as the removal of the voice box, a mastectomy, and the amputation of limbs, be so fearsome?
Unfortunately, people are misinformed and lacking in knowledge about modern radiation therapy. Also, most people's perceptions of radiation therapy are colored by the unfortunate anecdotes they've heard. Most people have not yet put the horror stories into their proper perspective. After all, one hears about bad outcomes when people travel inmotor vehicles. Yet, people do not fear the potential dangers of driving or being a passenger they way dread the thought of radiation therapy. Furthermore, society does not make the distinction between cleanly prescribed medical radiation treatment and nuclear accidents like Chernobyl.
In addition, most people are unaware of advances that revolutionized radiation therapy in the new millennium. After all, radiation therapy in 2005 is a world apart from what it was more than 100 years ago, when Madame Curie and the other pioneers in the field discovered that x-rays shrank malignant tumors. Radiation therapy was largely an art at that time, with a whole body of science waiting to emerge.
Originally, radiation treatments were delivered with radioactive materials, called isotopes, such as radium. These substances were placed on, in, or along side of tumors. People subsequently sustained burns and other devastating complications. Besides, the earliest radiotherapy machines did not have energy high enough to penetrate deeply to the area of interest, also known as the target, such as a lung tumor or the prostate gland. Instead, the radiation unintentionally deposited a substantial dose on the skin, resulting in burns. What also complicated matters was the fact that these machines were stationary, and could not rotate around the area that needed to be treated.
Today, such equipment has been supplanted by sophisticated, computer driven, high energy linear accelerators. Therefore, radiation oncologists today can treat a target from multiple angles, thus spreading out the radiation dose instead of concentrating it on only one area. This is one measure that protects normal tissue.
In the early days of radiation therapy, there were no treatment planning computers to perform dosimetry, the precise measurement of the radiation dose in the target and the normal tissues through which the radiation beam passed.
Also, there were no data at the time to show that by prescribing radiation therapy in a protracted manner over several days, weeks, or months, the normal tissues recovered from the insult of radiation, while tumor cells died and were naturally eliminated by the body.
Today, radiation oncologists know how much radiation therapy each organ can tolerate before it incurs injury. Hence, radiation therapy can be safely prescribed to treat the target properly, yet spare the healthy, surrounding organs from collateral damage.
When the radiation oncologist cannot avoid treating the skin, such as when the chest wall is irradiated after a mastectomy to prevent a recurrence on the chest wall, a prophylactic treatment break is given to prevent or reduce the severity of a burn. Also, such a burn is temporary, and with proper care, patients get through it.
Through the evolution of radiation therapy, radiation oncologists have learned that shaping the treatment field to conform to the shape of the target limits the amount of normal tissue exposed to radiation. This means that the treatment field, which is normally a square or a rectangle, can be shaped with lead blocking devices to match the shape of or target. Modern techniques use CAT scans and 3-D treatment planning computers for this purpose.
More sophisticated imaging tools, such as high resolution CAT scans, MRI scans, and PET scans, further enable radiation oncologists to limit radiation therapy to the target. For example, CAT scan and conformal blocking techniques for breast cancer allows the treatment team to spare virtually all the heart when the left breast or chest wall is treated.
Taking these tools to the next level, targeted radiation therapy techniques have evolved over the past decade. These ensure the radiation hits the target precisely, which is especially important for organs that shift, such as a lung tumor with respiration and the prostate with bladder and rectal emptying and re-filling. Such innovative technology eliminates any uncertainties in defining and treating the target, thus enabling the use of much smaller treatment fields. Also, radiation oncologist can now safely treat to higher doses, which potentially translates into more cures.
Fortunately, contemporary radiation therapy is generally a kind and gentle treatment that is highly effective at controlling the symptoms of cancer and at curing the disease, with few or no side effects.
Dr. Kornmehl is a board certified radiation oncologist and author of the critically acclaimed consumer health book, The Best News About Radiation Therapy (M. Evans, 2004). Her website is RTSupportDoc.
Copyright 2006 by Carol L. Kornmehl. All rights reserved. No part of this article may be reproduced without express written permission of the author.
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