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The most effective and at the same time most gentle treatment for advanced or aggressive prostate cancer is afterloading.
In this form of brachytherapy, a high-dose radiation source is briefly introduced into the prostate. This proven treatment method is based on remote-controlled "afterloading" of the iridium radiation source into puncture needles inserted through the perineum. The radiation source is focused for a certain time at precisely calculated positions. In this way, an optimal dose distribution is achieved.
Depending on the findings, this treatment is performed 3 to 4 times under a short anesthesia, each time at an interval of about 1 week.
The most effective and useful treatment for advanced or aggressive prostate cancer is HDR afterloading combined with external beam radiation. The advantage of HDR afterloading therapy over external irradiation alone is that a maximum dose increase can be achieved by precisely targeting the prostate while reducing the radiation dose to the surrounding organs at risk, especially the rectum and urinary bladder. Complications and stress for the patient are thus greatly reduced.
Combined afterloading therapy is particularly effective for locally advanced prostate carcinomas without distant metastases, as it includes a large safety zone around the prostate and also covers the neighboring lymph nodes. This large safety zone makes it clearly superior to surgery.
Geeignete Patienten für eine Afterloading-Therapie in Kombination mit einer äußeren Bestrahlung sind Risikopatienten mit einem lokal fortgeschrittenen Prostatakarzinom ohne Fernmetastasen in Knochen und Lymphknoten (T2b und/oder PSA >10 und/oder Gleason-Score >7). Bei Patienten mit einem geringen Risiko (T1b-T2a, PSA < 10, Gleason-Score < 7) wird die Technik derzeit im Rahmen von Studien untersucht. Wie zahlreiche Studien bestätigen, ist die Heilungsrate der Kombinationstherapie bei geringer Veränderung der Lebensqualität der operativen Entfernung der Prostata eindeutig überlegen. In einer aktuellen Studie des Westdeutschen Prostatazentrums konnte gezeigt werden, dass eine kombinierte Strahlentherapie bei Patienten mit fortgeschrittenem Prostatakarzinom zu einer hervorragenden Heilungsrate führt und gleichzeitig nicht die Lebensqualität der Patienten beeinträchtigt. Hinzu kommen deutlich geringere Inkontinenz- (< 1-3%) und Impotenzraten (20 – 40%) als nach der operativen Entfernung der Prostata. Ein weiterer Pluspunkt: Die Patienten sind in der Lage berufliche und private Aktivitäten schon nach wenigen Tagen wieder aufzunehmen. Bei der HDR-Brachytherapie handelt es ich um einen kleinen schonenden Eingriff, der in der Regel kurzstationär durchgeführt wird und für den Patienten nur eine geringe Belastung darstellt.
Before afterloading therapy
After the urologist and radiotherapist have given the indication for afterloading therapy, "pre-planning" is carried out prior to the procedure using transrectal ultrasound via the rectum. The resulting images are transmitted to a planning computer. Based on the size, shape and location of the prostate, the radiation therapist calculates the feasibility of afterloading therapy
Blood-thinning medications such as aspirin, ASA, Eliquis, Lixiana, Plavix, Xarelto, Marcumar or comparable preparations must be discontinued one week before the operation in consultation with the attending physician. Two days before the operation, the patient should start taking an antibiotic and an alpha-blocker as prescribed by the physician. The day before the procedure, foods that are difficult to digest should be avoided. No food or drink is allowed for six hours before the procedure. The evening before the procedure, laxative measures are taken to empty the rectum.
The procedure of afterloading
Under a short anesthesia and ultrasound control, the urologist sterilely inserts special hollow needles through the perineum to the calculated positions in the prostate. The previously inserted bladder catheter serves to precisely identify the urethra in order to spare it as much as possible during the subsequent planning of the dose distribution. In the next step, ultrasound tomograms are taken for radiation planning. With the help of a special computer program, a 3D model of the prostate is created and the radiation therapist calculates the dose distribution and required loading of the individual hollow needles with the Iridium-192 source. The tiny radiation source can scan each position of the needle in millimeter increments and deliver its radiation at the calculated breakpoints over a defined period of time. In total, up to 200 possible stopping points of the radiation source are defined.
After the irradiation plan and dose distribution have been completed, all needles are connected to the afterloading device by means of thin extension tubes. Only then does the actual irradiation take place, i.e. the radiation source now moves down needle by needle and irradiates the tumor on site. The needles are firmly fixed in the prostate, so that the target and risk organs do not change their position and distance from each other. The pure irradiation time lasts only a few minutes and the patient is in a special radiation protection bunker during this time. Just as with seed implantation, urologists and radiation therapists can follow the treatment on the monitor in real-time transmission using the latest computer technology. The smallest deviations of the implantation needles from the previously calculated radiation plan are immediately taken into account and optimized accordingly. After the prostate has been completely irradiated, the needles and catheter can be removed again and the patient can wake up from the anesthesia. The procedure usually takes 45 to 60 minutes. There is usually a week's break between treatments. The additional external radiation takes about 6 weeks. In total, radiation is usually administered approximately 30 times to a total dose of 50-55 Gy, five days per week.
After afterloading therapy
The urological follow-up examinations, such as the determination of the PSA value, an ultrasound examination, and the recording of side effects using standardized questionnaires, are initially performed quarterly. Normally, patients can resume their professional activities within a few days after the procedure. During the initial period, those undergoing treatment should take it easy on themselves physically and pay attention to the following: Bathing, swimming, sauna visits, sexual activity and heavy lifting should be avoided for the first two weeks. Pressure on the prostate and perineum, e.g. from cycling, horseback riding or sitting on hard surfaces, should be avoided for about four weeks.
The side effects of HDR afterloading are minor. Since the afterloading procedure is usually combined with external irradiation, local irritation of the bladder and bowel may occur. After external irradiation, some patients also complain of fatigue. The side effects usually disappear on their own after the treatment is completed. Immediately after the procedure, some patients experience more frequent urination. This is caused by a temporary mild irritation due to the insertion of the catheter.
