Chemotherapy is the delivery of drugs to treat disease, most commonly cancer, and radiation therapy is the use of high energy ionizing radiation to inhibit the division and growth of cells (usually cancer cells). Both of these therapy options are highly effective in treating many types of cancers; however they can also affect the normal healthy cells in the body, inducing unwanted side effects. Most of the side effects from chemotherapy and radiation subside when treatments end, but there are some that can be long-term.
Dryness
Mucous membranes and glands, such as salivary glands and tear glands, are sensitive to radiation and some chemotherapy medications. Radiation therapy to the head and neck region can induce xerostomia (dry mouth) and xerophthalmia (dry eyes). Radiation can also affect the sweat glands, causing them to stop working and making temperature regulation difficult. These conditions may be long-term and do affect the patient's overall quality of life.
Hair Loss
Hair follicles contain rapidly growing and dividing cells making them susceptible to damage from both chemotherapy and radiation therapy. This damage causes hair loss, which is usually temporary. Chemotherapy can cause hair loss over all of your body, but radiation only causes hair loss to the localized area where it was administered. Depending on the medication and the level of radiation, the damage to the hair follicle can be extensive enough to induce permanent hair loss.
Secondary Tumors
A secondary tumor is the formation of a new and unrelated cancer as a result of the treatment of another cancer. The secondary cancer usually arises months, or more likely even years after the initial treatment. Both chemotherapy and radiation are known carcinogens, meaning they can cause cancer. The risk of secondary tumors is usually so low that the benefits of the treatment outweigh the risks, but your doctor will continue to monitor your overall health, even after treatments have ended.
Hearing Loss
Chemotherapy medications, especially cis-platin, can cause tinnitus, which is a ringing sensation in your ears. There is no specific treatment for tinnitus, so it can lead to hearing loss. Radiation therapy administered to the brain can cause damage to the inner ear, resulting in hearing loss as well.
Infertility
The cells of the reproductive system for both men and women are rapidly dividing cells, making them vulnerable to damage from both chemotherapy and radiation therapy. For men, chemotherapy treatments can cause permanent damage to the testes that produce the sperm as well as the sperm. Radiation to the area of the testes reduces the number and functionality of the present sperm. High doses of radiation can induce long-term effects. In both cases you may want to consult your doctor about freezing some of your sperm to ensure your ability to father children in the future.
Chemotherapy can cause permanent damage to the ovaries, which are responsible for producing hormones essential to fertility. Radiation therapy to the pelvis region can cause women to experience signs of menopause, which may be long-term if the radiation dose is high.
