Radiation therapy for rectal cancer

To reduce the chances of a malignant cancer of the rectum returning to the same place later (called a 'recurrence'), radiotherapy is given prior to surgery in some cases. Tumour cells that attempt to move away from the original tumour (e.g. through the lymph vessels) will be neutralised as much as possible with this radiation therapy. The cancerous tumour itself is often reduced somewhat already. This increases the likelihood of tumour-free margins during the final surgery.

For tumours very low in the rectum or very large tumours, long-term radiation therapy for the rectum is the more likely option. This runs over about six weeks. Radiotherapy is combined with the administration of chemotherapy to make the tumour extra sensitive to the radiotherapy. After such a long radiation therapy cycle, a break of at least six to eight weeks will be scheduled before performing the operation.

For tumours that are higher in the rectum, the choice may be for a five-day 'short' course of radiotherapy sometimes. This involves administering a slightly higher dose daily. In this case, the surgical procedure is performed in the week following the radiation therapy.

Radiotherapy or radiation as the sole treatment of rectal cancer (so without additional surgery) is only applied in exceptional cases. At present, we cannot consider this therapeutic option to be an equal alternative for surgery.

Latest publication date: 16/05/2024