There have been significant advances in radiotherapy in recent years, with much less damage to normal tissue than before, but some side effects may still occur in some patients. This article will focus on the side effects associated with radiotherapy.
Why do side effects occur with radiation therapy?
Why do side effects occur with radiation therapy?
In terms of the choice of the area to be irradiated, radiotherapy will include a small amount of normal tissue around the tumor. This is to prevent the tumor from spreading to the surrounding normal tissues and to reduce the risk of recurrence; on the other hand, the tumor will change in location and size after several irradiations, so the irradiation area needs to be expanded appropriately to ensure that the target area is not missed.
In terms of the principle of radiotherapy, the radiation has to pass through the skin and other normal organs before reaching the lesion, thus causing more or less damage to the normal tissues of the pathway.
The following factors can contribute to the side effects of radiation therapy:
- Tumor size and location. If the tumor is large and invasive, with a correspondingly large amount of normal tissue being irradiated, the likelihood of side effects is relatively high. The risk of side effects is also relatively high when the tumor is close to other normal tissues or directly involves other tissues. For example, when stomach cancer involves the esophagus, side effects such as pain after eating can occur after radiation therapy.
- Radiotherapy dose and dose distribution. This is the most important factor affecting the efficacy and side effects of radiation therapy, and different doses and ranges of irradiation affect the body differently.
- Patient health status and individual differences. The degree of tolerance to radiotherapy varies from patient to patient, and it is important to maintain good physical condition and mental health during treatment.
- Systemic reactions, including fatigue, dizziness, low blood count, anemia, infection, and bleeding, are extremely unlikely and mild and usually do not require special treatment.
- Gastrointestinal manifestations, including gastric mucosal damage, esophagitis, manifesting as dyspepsia, diarrhea, and epigastric discomfort. Generally, radiation gastritis is bound to occur after radiotherapy beyond a certain dose, and the gastrointestinal response above grade 3 can be as high as 57% when conventional and conformal radiotherapy techniques with simultaneous radiotherapy are applied. However, with the advancement of radiotherapy technology and the use of intensity modulation, the percentage of severe gastrointestinal tract injury can be less than 5%. Usually, minor gastrointestinal tract injuries can be left untreated, while severe cases will be treated symptomatically with drugs. Gastrointestinal reactions usually resolve gradually after the end of radiation therapy.
- The liver, kidneys, pancreas, and spinal cord may also be slightly damaged during radiation therapy for gastric cancer. However, with current advances in radiotherapy technology, damage to these organs is usually asymptomatic and usually does not require special treatment.
What are the possible side effects of radiation therapy for gastric cancer?
Gastric cancer radiation therapy may have side effects.
The tissues and organs that may be affected by radiation therapy for gastric cancer include the stomach, intestinal canal, liver, pancreas, kidney, and skin. In terms of time of occurrence, radiotherapy side effects are divided into acute phase side effects and late phase side effects.
Acute side effects
Acute side effects
Acute side effects usually occur 1 to 2 weeks after starting treatment and usually disappear with the end of treatment and include the following.
Late side effects
Late side effects become progressively apparent months or years after treatment, but they last longer. Late side effects mainly manifest as gastrointestinal reactions, such as gastrointestinal ulcers, perforations, fibrous strictures, and intestinal obstruction. The probability of late side effects is extremely low and can usually be avoided with advanced radiotherapy techniques.
As a local treatment, the side effects of radiotherapy are also mainly local and in most cases are mild and not a cause for excessive concern. It is important for patients to have the right attitude toward radiotherapy and the possible side effects of radiotherapy. During radiotherapy, patients should follow the doctor’s instructions and cooperate actively. They should usually have their blood tests, liver and kidney functions checked once a week, and try to eat easily digestible food and avoid overheated food. Inform your doctor promptly of any discomfort. (Contributed by Junhua Zhao, Department of Gastrointestinal Oncology, The First Hospital of China Medical University)