Radiation therapy is another option for men with localized prostate cancer. It is offered to the same men who are offered radical prostatectomy. They have cancer confirmed by biopsy that, as far as is known, is confined to the prostate. They, too, should be relatively, younger men who would normally expect to have at least ten years of healthy life ahead of them.
Radiation therapy has the big advantage of offering a cure without surgery. As prostatectomy is a major operation with all the usual risks, this advantage cannot be underestimated. However, it has its disadvantages, first of all it does not help BPH, so it can leave men with bladder outflow problems that still need treatment, and perhaps TURP. The radiation can injure the nearby bowel and bladder, so that some men who have had it need operations to repair the damage. A small number have been reported, for example, to need a colostomy (a bowel opening in the front of the abdomen) because the radiation has damaged the rectum.
Radiation treatments take a long time – they need many sessions in the radiotherapy department, which can be daunting. Unlike radical prostatectomy, radiation therapy leaves the prostate behind, so that there is a potential for future cancers to develop, and for men to remain anxious about it. Of course, there is also the objection that, like radical prostatectomy, the radiation therapy may not be needed, because the tumor will not grow fast enough or spread wide enough to cause serious illness or death.
Reading the two paragraphs above would put anyone off considering radiation treatment, but they should be put in context. Today, before you have any form of treatment, you must be fully informed about its possible disadvantages: this is as relevant to radiation therapy as it is to surgery. That is why everyone considering radiation therapy should know what can go wrong. The converse is that a lot can go right.
The main form of radiation therapy using an ‘external beam”, when given to the appropriate men, has excellent survival rates. Major American studies have reported more than half of their men surviving healthily for more than 15 years.
This is similar to survival after radical prostatectomy and also to the 15-year survival rates in men of similar age without known prostate cancer. In other words, most men who have radiation therapy for their prostate cancer can look forward to living a normal and long life.
Those American figures, published in the early 1990s, relate to radiation treatments given in the 1970s. Today’s techniques, in which the radiation beam is much more focused on the tumor itself and causes much less radiation damage to nearby tissues, should offer even better results and many fewer complications than those of a generation ago. Nowadays, too, many prostate cancer specialists offer, along with the radiation, surgery to remove possibly affected lymph glands in the pelvis. Such surgery is much less complex and serious than radical prostatectomy, and may ‘catch” the few men with early spread that is not detectable under the usual tests.
Once you have had your radiation therapy, what then? You will be under surveillance for the rest of your life. You may be asked to have occasional needle biopsies, and you must have repeated PSA tests, to make sure that the cancer is not returning. The PSA does not fall so fast or to such low levels after radiation as after radical prostatectomy, partly because the prostate gland is still there, and some of the normal cells are still functioning (radiation ‘takes out” the cancer cells selectively). However, men whose PSA levels drop below 1 ng/ml after radiation have a much lower chance of a recurrence than those whose PSA remains above 4 ng/ml.
Failure rates of around 10 per cent after conventional external beam radiation have led some medical centres to use new methods to deliver a higher dose of radiation more accurately and more selectively to the tumor. One of these approaches is ‘conformal radiation”, in which a CT scan is used to make a three-dimensional model of the prostate, and the radiation beam is ‘shaped* to conform exactly to its outline. This appears to be not only more effective but also leaves fewer and less serious side effects than other radiation techniques. Other research institutes are using different types of radiation to kill the tumor cells, among them ‘fast neutrons”, protons and photons. Early results suggest that they all have very high response and cure rates, but they will not be widely available for some years yet.
Probably the biggest advance in radiation therapy is its use along with anti-androgen hormone therapy. The combination is thought to have two benefits. One is that any tumor cells that survive the radiation cannot multiply because they are being hit by the hormone effect. The other is that depriving the tumor cells of their androgen stimulus while at the same time exposing them to radiation is a double blow that may well kill them.
The results of trials of this combination of radiation followed by four months of androgen blockade have been published by the Radiation Therapy Oncology Group (RTOG) in two large studies. The first reported that in 93 per cent of the men their tumors were completely eradicated: they showed no recurrence up to at least two years later. The second compared radiation only with radiation plus anti-androgen treatment in men with disease that had advanced beyond the prostate into the pelvis. In these men, for whom complete cure is unlikely, by five years the disease had spread in 46 per cent of the men on combined treatment and in 71 per cent of those who had only had radiation. Twice as many men were completely free of their disease in the combined treatment group (36 per cent) than in the radiation-only group (15 per cent) after five years. These may seem low percentages, but do remember that the men concerned already had advanced disease before they had their treatment.
The best news of all comes from the European Organization for Research and Treatment of Cancer (EORTC). It compared radiation treatment alone with radiation plus anti-androgen treatment. Over the following three years there was complete local prostate disease control in 95 per cent of the men given the combined treatment and 75 per cent of those given radiation alone. Eighty-five per cent of the men on the combined treatment were metastases-free, compared with 48 per cent of the radiation-only group. Figures like these have led to a consensus that all men undergoing radiation treatment for prostate cancer should also have anti-androgen treatment for at least four months afterwards.
To summarize on treatments for early cancer that has not spread outside the gland into the pelvis or distantly :
– The final decision on whether to offer surgery or radiation, plus anti-androgen treatment, depends not just on the cancer specialist, but on you, the patient, and your family. You cannot make the decision without full information about your particular cancer and the risks and benefits of treatment. They differ from person to person, and you can only make an informed decision about whether to go ahead with a particular treatment if you know all the facts. You may only need to wait and see. You may need surgery or radiation therapy. You probably also need anti-androgen therapy. The decision ultimately depends on the discussion you have with your prostate cancer specialist