Radiation therapy affects both normal and cancerous cells, but normal cells are able to recover. Having treatments 5 days a week for several weeks spreads out the total dose of radiation and gives the patient weekend rest breaks. Nevertheless, the body must work very hard during radiation therapy to repair the tissues injured by the treatment. Patients may feel unusually tired, and they should try to rest as much as possible. Radiation therapy does not change the ability to have sex.
Radiation therapy does, however, interfere with sperm production.
Usually the effect is temporary, and most patients regain their fertility within a matter of months. Other unpleasant effects of radiation therapy include diarrhea, nausea, and vomiting. These problems can usually be controlled with medication. Also, there may be skin reactions in the area being treated, and it is important to treat the skin gently. Lotions and creams should not be used on these areas without the doctor's advice.