Following a radical prostatectomy, although the surgeon has felt that all the cancer has been removed, there are certain things, which can raise some doubt as to whether there might still be invisible, microscopic remnants of tumour left behind. These include:

• finding that when the prostate gland is examined under the microscope tumour cells come right to the edge of the tissue that was removed (another way of saying this is that tumour reaches the margins of the tissue so 'the margins were not clear')
• finding that when the prostate gland is examined under the microscope cancer cells had actually broken through the capsule which surrounds the gland and finding that cancer cells were present in the seminal vesicles (these are the small tubes immediately above and behind the prostate gland, which store the sperm and which are removed with the prostate gland during a radical prostatectomy)
• finding that the PSA has not returned to a normal level within three weeks of surgery being performed.

None of these things is proof that there are cancer cells present but they do raise the possibility that some cells might remain. Because any such cells would be very small further tests with scans or x-rays would not help in proving one way or the other whether they were still there.

In these circumstances your surgeon might discuss a course of radiotherapy treatment after the operation. This would involve external beam treatment, using a machine called a Linear Accelerator, since the alternative method, using implants of radioactive seeds (brachytherapy) would not be possible because of the changes to the local anatomy and scar tissue formation after the previous surgery.

Radiotherapy that is given after surgery which has apparently cleared the cancer but there is a risk of microscopic tumour still being present, is called adjuvant radiotherapy.

Although it seems logical to offer adjuvant radiotherapy after a radical prostatectomy if there appears to be a risk of some cancer cells still being present, the limited number of clinical studies that have looked at this situation have found that although the radiotherapy reduces any risk of prostate cancer coming back in the region of the previous prostate there is no obvious benefit in terms of long term cure or increased life expectancy. In addition the radiotherapy can increase the likelihood of troublesome side effects such as incontinence and impotence.

At the present time clinical trials are underway to try and get more information about the real value of adjuvant radiotherapy after radical prostatectomy.

In the meantime, if your surgeon has mentioned this, then the thing to do is to have a careful discussion with him or her to be clear about just what the possible benefits and risks might be in your particular circumstances.