Radiotherapy (also known as radiation therapy or simply radiation treatment) is frequently used in cancer treatment alongside surgery and chemotherapy.
One in two cancer patients receives radiation therapy at some point during the course of their illness. Drug-based (“systemic”) chemotherapy affects the entire body. Radiation therapy, on the other hand, is a purely localized treatment. The effects of the radiation are therefore limited to the area where the beams are directed—that is, the treatment field.
Radiation therapy can
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For some types of cancer, such as localized laryngeal cancer or prostate cancer, radiation therapy is the only treatment option.
In addition, radiation therapy can be used in cancer treatment to alleviate or prevent symptoms.
Malignant tumors are very frequently treated with radiation, often in combination with other treatments such as surgery and chemotherapy. About one in two cancer patients undergoes one or more courses of radiation therapy.
Depending on the purpose of radiation therapy, a distinction is made between
Cancer treatment always follows the principle of “logarithmic cell killing.” Tumors often consist of 100 billion individual cells. For the purpose of a cure, radiation therapy is designed to destroy the tumor down to the very last cell.
Since individual tumor cells can no longer be detected, the true success of the treatment only becomes apparent after months or years.
If the tumor recurs at the same site during the observation period, a recurrence is assumed.
A linear accelerator precisely targets tumors © Maksym Povozniuk | AdobeStock
In radiation therapy, cancer cells are destroyed by ionizing radiation or particle radiation.
The radiation damages the genetic material of cells, causing cell division to stop and the cells to die. The tumors shrink or even disappear.
The cell-damaging effects of radiation therapy are nonspecific. Healthy cells are also affected. However, depending on the extent of the damage, the cells’ own repair systems can repair damage to the genetic material. Like a pair of scissors, they cut out sections of the DNA and replace them.
This ability to regenerate genetic material is more pronounced in healthy cells than in cancerous ones. While healthy cells normally regenerate, cancer cells die and are removed by the body’s own immune cells.
However, healthy cells need enough time to repair damage to their genetic material. For this reason, in radiation therapy, the total radiation dose the patient is to receive must be divided into several individual sessions (fractions).
The doctor selects the radiation dose based on the tumor’s sensitivity to radiation. If a cure is necessary, the radiation dose ranges from 40 to 70 Gray (Gy). The total dose required to destroy the tumor is divided into fractions of 1.8 to 2 Gy each (standard fractionation). This ensures good tolerability and reduces the risk of irreversible damage and late complications.
However, the healing capacity of healthy tissue remains the limiting factor for curative radiation therapy.
New precision radiation techniques allow for the precise localization of tumor tissue. As a result, less healthy tissue is affected during radiation therapy. Such techniques enable what is known as hypofractionated radiation therapy, in which the required radiation dose is administered in multiple fractions. Less attention should be paid to the recovery of healthy tissue.
In most cases, radiation therapy is administered “externally.” This means that the radiation is generated by a special radiation machine and directed through the skin (“percutaneously”) to the tumor inside the body.
These devices that generate radiation are called linear accelerators. A linear accelerator accelerates electrons to nearly the speed of light. The electrons escaping from the accelerator can then be used directly to treat superficial tumors.
However, when treating deeper tumors, the energy of the electrons is first converted into X-rays (photons) through a physical process. X-rays have a greater penetration depth in tissue than electron radiation.
Typically, the penetration depth of a type of radiation increases with increasing energy.
The administered dose of radiation energy increases steadily over the course of treatment. Therefore, side effects may sometimes not peak until 7–10 days after the end of therapy. After that, they gradually subside.
It is important to continue with the prescribed care until the side effects disappear. Most side effects should subside within 4 weeks. This timeframe may vary depending on your personal sensitivity, the area of exposure, and the energy dose.
In some cases, the skin may
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Sometimes, the exposed skin may also develop a tan (pigmentation). Irradiated skin is sensitive to mechanical irritants. Therefore, you should take care of your skin from the first radiation exposure until three weeks after the end of treatment: Avoid anything that irritates the skin and, above all, causes stress.
Thanks to technological advances, severe skin reactions are much rarer today than they used to be. Any skin reactions may persist for some time after the end of therapy and may sometimes temporarily worsen.
In the first few months after exposure, the skin is more sensitive to light and sunlight. Make sure you have good protection against the sun and cold wind during the first 12 months after exposure.
After radiation therapy, the skin must be protected from potential environmental factors © matusciac | AdobeStock
Likewise, the other side effects of treatment should subside within a few weeks after treatment ends. Depending on your specific situation, you will receive detailed information about this at the end of treatment.
Patients often complain of drowsiness or fatigue after tumor treatment. Some patients take longer to recover. Try to eat normally. Light exercise or moderate physical activity can support your recovery.
Like any other treatment, radiation therapy can have side effects. Symptoms that may occur during or after radiation therapy depend on various factors. These include, for example, whether you have already undergone surgery or received chemotherapy.
The type and extent of radiation therapy also play a role. As with surgery, the more extensive the radiation therapy—that is, the more widespread the disease—the more side effects you may experience.
Before and during treatment, your doctor will discuss with you in detail what you can do to minimize side effects during radiation therapy.
Every physician listed in the Leading Medicine Guide has attained the highest level of training and certification within their respective medical specialty society. Furthermore, we contacted this physician based, among other factors, on their case volume (surgeries, treatments, and therapies), which we determined by cross-referencing various publicly available sources. Following discussions with the selected physicians and the directors of the medical facilities, as well as a subsequent internal review, they were admitted to the Leading Medicine Guide.
The quality assurance of the Leading Medicine Guide is further ensured by 8 admission criteria. Each member must meet at least 6 of them:
