Radiation therapy offers a great benefit in the treatment of cancerous tumors, due to its ability to damage DNA needed for the replication of quickly multiplying tumor cells. However, the normal cells in the human body are also subjected to the powerful radiation during therapy and there are some side effects that patients may experience as a result.
Notably, most side effects are localized to the area of the body that was targeted in treatment and lower doses of therapy are less likely to cause side effects.
Skin Irritation
Many patients notice changes to the skin that is penetrated by the radiation used in therapy, which usually become evident a few weeks into treatment. It is often described as similar to moderate sunburn with slight reddening of the skin and soreness in the area. As treatment continues, it usually becomes more severe until it reaches a peak about one week following the end of therapy. From that point, the skin usually recovers well, however it is often not as elastic as it was prior to surgery.
In addition to the skin, epithelial surfaces that may be affected by the radiation include the oral mucosa, pharyngeal, bowel mucosa and ureter.
Fatigue
It is common for patients to experience feelings of fatigue during therapy. This usually begins mid-way through treatment and can continue for weeks after the conclusion of therapy. This effect is thought to be as a result of the body’s response to the need of healing the cells exposed to irradiation damage.
Nausea and Vomiting
Localized treatment to the stomach or abdomen is associated with feelings of nausea and possible vomiting, which usually begin a few hours following therapy. In addition, radiation directed towards the head can lead to vestibules of the inner ear to cause nausea.
It is also possible for people to experience nausea and vomiting due to psychological effects of therapy, particularly if they have also previously had treatment of chemotherapy. These symptoms may begin during or immediately before therapy.
Local Ulceration
The area that is being targeted by radiation therapy may be affected and some areas are prone to ulceration. For treatment of the head or neck, ulceration in the mouth or throat is common and may affect the ability to swallow. As a result, there may be need for specialized nutritional support to cope with this.
Other areas along the gastrointestinal may also be affected when subjected to therapy such as the esophagus, stomach and intestine.
Infertility
Both the male and female reproductive systems are sensitive to radiation and the function of the ovaries and testicles can be altered as a result of treatment. Where possible, exposure of the gonads to radiation should be avoided, or at the least minimized to avoid infertility. Infertility can be avoided if at least one gonad is spared from exposure.
Bowel Incontinence
Radiation directed towards the pelvic area can eventually lead to bowel incontinence and the inability to control bowel movements. Often long-term dietary changes are needed to manage this and medications or surgery may also offer a solution.
Lymphoedema
The lymphatic system can be damaged by radiation therapy, affecting the body’s ability to drain excess fluid effectively. As a result, it is common for fluid to build up and lead to lymphedema and associated swelling and pain. This usually occurs in the arm or legs and can develop a significant amount of time after radiation therapy.
Secondary Cancer
Radiation therapy is also associated with a slightly increased risk of secondary cancer, which may occur many years following radiation therapy. However, for most patients the benefits of treating the localized tumor greatly outweigh this risk.
References
Further Reading
ASTRO releases updated guidelines for treating locally advanced rectal cancer