Acute side effects are sometimes referred to as "<b>early side effects</b>." The symptoms may occur soon after the treatment begins and usually are gone within a few weeks of finishing therapy. "<b>Late effects of radiation</b>" is permanent damage and may take months or years to develop and can be progressive. 

<b>Acute radiation damage from abdominal or pelvic irradiation</b> will usually present with skin reaction, digestive tract reaction and/or bone marrow depression. White blood cells and platelets decrease rapidly. Red blood cells also can decrease. These symptoms go away in a matter of weeks. The damage to the bone marrow is cumulative, however, and repeated irradiation or chemotherapies can result in myelodysplasia [See Myelodysplasia]. Acute severe digestive tract reaction increases the risk for late effect radiation damage. 

The incidence of <b>late effect abdominal radiation effects</b> depend upon the type of radiation, the amount of exposure, and the fields chosen, as well as other, patient-related, factors. It is best to ask the oncologist who is prescribing the radiation, for the acute AND late effect risk profile involved in the particular regimen he has chosen. Discuss alternatives with him/her, as well as ways to shield other organs or remove them from the field of irradiation. 

<b>Late Effects of Radiation: Permanent Radiation Damage</b>
  
Essentially, the late effects of radiation are probably due to one of two processes occurring in exposed tissues: