Читать книгу The Cancer Directory - Dr. Daniel Rosy - Страница 111

Tumours are given a dose of radiotherapy that is close to the maximum tolerated by the normal tissues in the area being treated. The risk of damage to normal tissue is the major factor limiting the dose of radiotherapy given. There is also an overall limit to how much radiation can be given to one area or the whole body.

Should the tumour recur, further radiotherapy to the previously treated area may then exceed the normal tissue tolerance, so it is unusual to be able to repeat a course of treatment if there is a recurrence in the same place. Especially sensitive structures include the brain, spinal cord, lungs, liver and bone marrow, and great care is taken not to cause radiation damage in such areas.

It can be very frustrating for someone who responded well to radiotherapy the first time not to be able to have further radiotherapy for a tumour recurrence at the same site.

Radiotherapy, like surgery, is a form of local treatment. So if the tumour has spread beyond the confines of its primary site, radiotherapy cannot be considered a curative treatment.