External beam radiation therapy is one of the options of localized prostate cancer curative treatment.
The treatment usually takes place over a period of 6 weeks with 2 to 3 weekly sessions on average.
Every session is carried out as an out patient procedure in the radiation therapy center; the patient is not hospitalized and goes home after he has received treatment.
He receives this irradiation lying on a radiation therapy table and beams cross his body through the skin, at the level of the region to be irradiated, from the prostate the lower abdomen.
The use of a full body scanner for prostatic location prior to delivery of irradiation according to the mode of conformational radiation therapy increases the treatments accuracy in the hopes of limiting irradiation of the neighbouring organs.
Modalities of the treatment, advantages, complications and risks of radiation therapy are explained in the patients notebook realised in collaboration with the SFRO (French Society of Radiotherapy and Oncology) and the LNCC (French National League against Cancer).
As irradiation efficiency is much better if the volume of the prostatic gland to radiate is reduced it is often necessary to combine radiotherapy with a hormonal androgenic blockage of testosterone secretion during 6 months to 2 years according to each case.
This blockage results in erectile impotence, possibly reversible at the end of this treatment, unless the also inevitable irradiation of erector nerves perpetuates this eventuality.
In certain cases, function of PSA levels on diagnosis, as well as evaluation of the pelvic lymph nodes before delivering the radiotherapy is necessary when considering malignancy invasion.This evaluation requires a surgical procedure, a pelvic lymphadenectomy, which can be realized in a mini-invasive way by laparoscopy.
The results of external beam radiation therapy in terms of absence of recurrence of prostate cancer are equivalent to those of the surgery within the first 5 years, but decrease over longer periods of time.
The risk of prostate cancer recurrence after surgery or external beam radiation therapy can be estimated for each patient according to statistical data: Cattan nomogramm, Partin tables, Sloan Kettering Memorial Hospital calculator, etc…
In case of prostate cancer recurrence after external beam radiation therapy, the diagnosis is evoked by a rise in PSA levels on 3 successive tests (rising PSA) within regular intervals of a few weeks, compared with the lowest PSA level reached after completion of irradiation (PSA Nadir).
Determination of this PSA Nadir is not so easy as the interpetation of PSA levels after surgery when it has collapsed is close to zero.
Recurrence of prostate cancer after external beam radiation therapy is not usually accessible to surgical treatment (salvage prostatectomy) because of the local tissue modification. This sclerosis is the consequence of the very important beam doses necessary for the treatments efficiency as delivered by modern radiation therapy.