Introduction to radiotherapy
Radiotherapy is the use of controlled, focussed X-rays to damage cancerous cells in your prostate. The aim is that the surrounding healthy cells recover whereas the cancerous cells do not. It can be used to cure localised prostate cancer i.e. where it is in the prostate and the seminal vesicles. It can also be used when it has spread to the glands in the pelvis. There are two main types of radiotherapy: externally delivered (external beam radiotherapy – which is what we are discussing here) and internally delivered, which is known as brachytherapy.
Radiotherapy is particularly useful where patients are worried about the risk of incontinence with surgery, where they are not eligible for surgery, or where they are worried about the risk of significant bladder irritation with brachytherapy. Radiotherapy can also be used if surgery has not been successful. Patients below the age of 55 – 60 years old tend not to be treated with radiotherapy due to the small risk of radiotherapy causing a new cancer after several decades, despite curing the prostate cancer.
There is no definitive proof that any of the whole gland treatments (radiotherapy, brachytherapy, surgery) is better than another.
How is radiotherapy given?
External beam radiotherapy tends to be given as a daily treatment over a number of weeks (generally 4 – 7 weeks). Each treatment requires the patient to lie on a hard couch while a machine moves to various positions. Nothing touches the patient. The process is entirely painless, and does not involve needles or an anaesthetic. Each treatment takes ten minutes per day. It does not make the patient feel drowsy or dizzy, and patients can drive and continue to work through the course of treatment.
The X-rays are aimed very exactly at the prostate gland, using a dose-shaping technique (IMRT), and a guidance technique (IGRT), to ensure that the prostate is targeted exactly each day, and the other organs (rectum and bladder) are not treated with too high a dose of radiation.
Radiotherapy tends to be given with a course of hormone treatment that blocks testosterone (either tablets or injections), as this has been shown to make it more effective.
After your course has finished, you will have a PSA test and a check up between 3 weeks and 6 months to see how your prostate has responded. Your PSA level should begin to drop after radiation but can take several years to reach its lowest level. A stable and low PSA level indicates successful treatment.
What side-effects can you get?
During the first two weeks of treatment, there do not tend to be any side-effects, but towards the end of the treatment, some patients experience irritation of the bladder and bowel, which can cause diarrhoea, and frequency of emptying the bladder. In most people this is fairly mild and temporary, and this treatment does not cause incontinence of the bowels or bladder. However, 5 – 10% of patients have longer-terms bowel or bladder side effects.
Additionally, there is a risk of causing loss of erections in the long-term with this treatment, although often this can be treated successfully with treatments such as Viagra.
How successful is radiotherapy?
The success of any curative treatment depends on many factors, but particularly how high a risk your tumour was. Factors would include the PSA, the Gleason score, and stage (i.e. how far the tumour has spread in and around the prostate).
There has never been a robust comparison of the curative treatments. Therefore, it is important to discuss the success rate of the treatment in your own case, the impact of the process (e.g. number of hospital visits, having a general anaesthetic), as well as the side-effects that you would find most troublesome.
What treatments are available if radiotherapy is not successful?
The treatment would depend on the area in which the tumour recurs:
- If the tumour recurs in or around the prostate area then various treatments can be used to aim to cure the tumour, including surgery and HIFU (high-frequency ultrasound).
- If the tumour recurs in up to three places outside the prostate region, e.g. in the bones or the lymph glands, then a highly-focussed dose of radiotherapy called stereotactic body radiotherapy (SBRT, SABR) can be used to treat them.
- If neither of these types of treatments are possible, then “systemic” treatments would be offered, for instance hormone treatments or chemotherapy.