High energy X-rays can be used to kill cancer cells and shrink tumors. External radiation is delivered by a machine outside the body. Special drugs can be used to kill cancer cells. The drugs may be taken orally or injected into a vein. Chemotherapy is usually a systemic treatment, meaning the drugs enter the bloodstream, travel through the body and kill cancer cells throughout the body.
Recurrence refers to a cancer coming back after it has been treated.
In colorectal cancer, the chance of recurrence depends largely on the surgeon's skill in removing the cancer and the lymph nodes involved. The greater the surgeon's skill, the more complete the removal is likely to be. In general, the more complete the removal, the lower the risk of recurrence. Some cancers, however, are more aggressive than others. In these cases, in spite of the best surgery by the most skilled surgeon, the cancer has a greater probability of recurring.