Radiotherapy treatment is planned and delivered with the utmost care, but sometimes sensitive parts of the body are damaged. This is because to treat the cancer effectively, it is sometimes necessary to use high doses of radiation, close to the limits that normal tissues can withstand. The bowel, bladder and nervous system are particularly sensitive, but other parts of the body can suffer long term changes.
If you are having radiotherapy aimed at killing your cancer cells, there is about a 5% possibility of side-effects which may seriously affect your lifestyle. However, it is important to balance this against the much higher potential risks to your life, from the cancer getting worse or recurring without the treatment. On the other hand, if you are having radiotherapy to shrink the tumor and/or relieve symptoms, then the much lower doses of radiation used are unlikely to cause any permanent damage.
If the radiotherapy treatment includes the gonads (ovaries in women, testicles in men) this will affect fertility and hormone function. It is important to discuss this with your oncologist before treatment begins.
If you do have any difficulties at any time in the future which you feel may be connected with your radiotherapy, then do not hesitate to contact your oncologist or GP. If there are any special risks or problems in your case then your oncologist will discuss this with you.
Bear in mind that you are being offered radiotherapy because the benefits greatly outweigh the risks.