Madrid, April 14, 2021- Prostate cancer is the most common form of male cancer, with more than 35,000 new cases a year in Spain and a prevalence of 26%1. However, when detected early, there is almost a 100% chance of cure. In this sense, the Radiation Oncology Service at MD Anderson Cancer Center Madrid offers a non-surgical treatment, Prostatic Radiosurgery (SBRT), as an alternative for patients recently diagnosed with a prostate neoplasia, which permanently eradicates the disease and whose main advantage is a reduction in the duration of treatment, from 4-7 weeks for more conventional treatments to 5 days, which is a great benefit for the patient.
Prostate radiosurgery is ideal for patients with whose disease is confined to the prostate or is localized prostate cancer, the most common (85%) of cases of this type of tumor. "It is a highly precise, curative technique with almost no side effects," says Dr. Juan Carlos Viera, specialist in Radiation Oncology at MD Anderson Madrid. The fundamental difference between radiosurgery and conventional treatments is the reduction in time achieved with this new technique. "With conventional treatment about 38-42 or 20-30 sessions are needed (depending on the fractionation chosen), while with prostate radiosurgery only 5 sessions are required", states Dr. Viera.
Radiosurgery clearly involves greater technical complexity when compared to the other two more common radiation therapies (radiation with conventional fractionation or with moderate hypofractionation), requiring more exhaustive systems for prostate localization in each treatment session (intraprostatic fiduciary seeds) as well as rectal protection systems (self-absorbing rectal-prostatic spacer gels, for example).
"In prostate cancer, because it generally grows more slowly, unlike most other tumors, hypofractionation is especially efficient. For that reason, this radiosurgery (or ultra-hypofractionation) technique may be considered the first choice (gold standard) for most localized prostate cancer cases”.
Technique procedure
To perform Radiosurgery/SBRT treatment, a rectal spacer with hydrogel is used. The procedure consists of introducing a water-soluble substance (which is absorbed in 3 months) between the anterior part of the rectum and the posterior part of the prostate to separate the rectum from the prostate and minimize toxicity in the prostate both in the short and long term. Likewise, and with the same procedure, 3 fiduciary seeds are implanted that will help us to monitor the prostate during each radiosurgery session and achieve the required precision.
Radiation proctopathy (or secondary caused by ionizing radiation) has 2 phases: acute, or that appreciated during or shortly after the completion of radiotherapy and which is usually mild and self-limited (it disappears a few weeks after treatment), and chronic, that appreciated a year after radiation, and which may be accompanied by minor, painless bleeding, but which can lead to the patient developing long-term iron-deficiency anemia, requiring local coagulative endoscopic treatments.
The technique of separating the rectum from the prostate allows maximum precision radiation (Radiosurgery or SBRT) to be delivered with a minimal dose to the rectum, thereby reducing both short and long-term toxicities to the minimum, making them almost negligible for patients treated. To do this, and a few days before planning radiation treatment, under sedation in the operating room and controlled by means of ultrasound from the rectum, the gel application procedure is performed transperineally by the center's Radiotherapy and Urology team. During the procedure, 3 fiduciary seeds will be implanted into the prostate and will later serve to be able to place the patient in the perfect position as planned on the accelerator that will administer radiation in each of the 5 SBRT sessions.
Therefore, the planned distribution of the dose is achieved, in which the prostate itself is treated but the surrounding healthy organs are unaffected, and can be reproduced with the maximum possible precision in each of the sessions.
References:
1. Figures on Cancer in Spain 2020. Spanish Society of Medical Oncology. Downloadable pdf document at https://seom.org ›resources› Cifras_del_cancer_2020