Technique of treatment
According to the results of the multi-center prospective randomized study ProtecT (2016), radiation therapy and surgical treatment demonstrate a strong anti-cancer efficacy and provide reliable disease control in the majority (more than 90%) of prostate cancer patients with a low and intermediate risk of relapse. Currently, the decisive factor in choosing antitumor treatment in this category of patients is the safety of therapy and reducing the risk of complications.
Consider the main types of therapy: surgical treatment, brachytherapy, stereotactic radiation, combined radiation therapy.
RPE, or radical prostatectomy, is a surgical procedure to remove the prostate gland, as well as surrounding tissue and lymph nodes. In such an operation with the gland, the seminal vesicles and a section of the urethral canal are removed in a single block.
RPE differs in the type of access and degree of invasiveness:
Open. There are two main types of access: perineal and retropubic.
Retropubic access involves an incision in the lower abdomen through which the prostate is removed and the local tissue.
The perineal technique is an open method in which a small incision is made in the area between the anus and the musculoskeletal SAC, that is, the scrotum. The technique allows you to remove the prostate, but when using it, you can also remove unfavorable tissues and nodes located near the gland. If cancer cells are found in the pelvic organs after perineal surgery, you will need to additionally perform a lymphadenectomy. Now the perineal technique is used very rarely.
Laparoscopic. Main accesses: through the preperitoneal space or the abdominal cavity. To operate, several small incisions are made on the front wall of the abdomen. Through them, special manipulators are inserted into the preperitoneal space or abdominal cavity and the prostate, pelvic fat, and regional lymph nodes are removed.
The laparoscopic technique is the most gentle. The doctor has access to the affected organ through a small incision in the lower abdomen. The camera and all the necessary tools are inserted into it. The camera feeds an image of the pelvic organs to the screen so that the doctor fully controls the process, and the patient receives a minimum of harm. With this method, blood loss is minimized, foreign organs are almost not injured, erectile function is preserved partially or completely, and so on.
Let's also look at the most common complications that can occur after prostate surgery:
- Incontinence. This complication occurs in 95% of cases immediately after removing a special catheter from the patient's bladder. Further, in 45% of cases, this complication passes 6 months after the removal of the prostate gland. In 15% of cases, incontinence persists for up to 1 year.
- Loss of erectile function-complete or partial. Doctors manage to significantly reduce this complication when performing laparoscopic prostatectomy. This method minimizes damage to the nerve stem cells of the pelvic organs. If after surgery there is a disorder of erectile function, the patient is prescribed a course of medication and external drugs that expand blood vessels.
Brachytherapy is the introduction of radiation sources into the tissues. This method is the "youngest" among the methods of treating prostate cancer. Today, this is one of the most popular methods of prostate irradiation, which provides a very high selectivity of the dose. The main feature of brachytherapy is that the prostate is irradiated from the inside – the source of radiation is introduced directly into it. This method makes it possible to apply high doses (100-140 Gy or more) while avoiding a high risk of radiation damage to non-cancerous tissues.
The rapid growth in the clinical use of brachytherapy, in comparison with surgical interventions, is due to the high efficiency, which is comparable to prostatectomy, with a much lower incidence of complications.
There are 2 types of brachytherapy, depending on the method of introducing the radiation source into the gland and its power:
- high-power, which is characterized by the short-term introduction of a high-power radiation source into the tissue;
- low-power-a low-power source is installed for the entire duration of treatment.
During low-power brachytherapy, a radiation source is implanted in the prostate tissue and remains in them until complete disintegration. For a long time, this type of brachytherapy was used most often for breast cancer. Most often, the isotope of radioactive iodine, i.e. I125, is used to perform therapy.
According to numerous studies, low-power brachytherapy does not provide the very high accuracy of irradiation. This is due to the displacement of the radiation source, changing the shape and size of the prostate, and affecting adjacent healthy organs. Because of this, the low-power technique is shown mainly to patients with the most initial stages, when the tumor is small and does not extend beyond the gland. Such brachytherapy has other significant disadvantages. The first is the high frequency of complications arising from the urinary tract, there may even be acute urinary retention and the need for epicystostomy, that is, the formation of a supralobal urogenital fistula, for a long time. At the heart of complications-edema of the prostate gland since it remains several hundred grains (foreign bodies). Also, radioactive grains, if they are long in the body, are sources of radiation that pose a certain danger to other people. Because of this, the patient's contact with relatives is limited (it is impossible to communicate closely with young children).
The most modern method of intra – tissue therapy is high-power brachytherapy. Radiation sources are automatically loaded and extracted. This radiation therapy has a fundamental advantage – high accuracy of irradiation, achieved by inserting needles under the control of a special ULTRASOUND device. At the same time, doses are calculated automatically and it is possible to quickly adjust the radiation treatment plan. The radiation source is located in the patient's body temporarily, so the level of complications is the lowest, compared to all radical methods of prostate cancer therapy, including a low-dose version of brachytherapy.
The technological features of the technique allow us to offer it to most patients, regardless of the size of the malignancy and its prevalence beyond the prostate. Also, high-power brachytherapy is the "gold standard" for combined treatment, that is, simultaneous use with remote irradiation in patients with unfavorable characteristics of the neoplasm.
The biggest drawback of the high-power method is the high requirements for the qualification of medical personnel, as well as the need to use high-tech equipment. This explains the low prevalence of the method in USA.
Contraindications to brachytherapy are divided into General and urological. The most frequent urological contraindications are serious violations of the urination process:
- IPSS (index of the urination quality questionnaire) more than 20;
- Volume of residual urine is more than 50 ml;
- Highest rate of urination recorded in uroflowmetry is up to 10 ml/sec;
- Transurethral resection of prostate soft tissue performed less than 9 months before the intended brachytherapy.
It should be noted that the large volume of the prostate, which is important for low-dose brachytherapy (50-60 cm3), almost does not limit the possibility of treatment in the mode of high-power methods.
- distant metastases;
- malignant tumors, infections, and inflammation of the bladder;
- malignant tumors, infections, and inflammation of the rectum;
- intolerance to anesthesia;
- absence of rectum due to previous operations.
These contraindications apply not only to brachytherapy but also to other methods of radiation therapy of prostate cancer.
STLT (stereotactic radiation therapy) is a high – precision method of treating the focus of prostate cancer with high doses of ionizing radiation.
Today, STLT for prostate cancer is implemented by several main methods, each of which has its characteristics, pros, and cons:
- The proton irradiation. The main advantage is the presence of a Bregg peak, which provides a high dosage gradient. However, this technique is more time-consuming and costs an order of magnitude more when compared with photon radiation therapy (including the cyberknife device and STLT, carried out on a linear accelerator).
- Cyber-Knife (installation of a cyber-knife) has a significant advantage, consisting of an almost unlimited number of directions of the radiation beam. This makes it possible to accurately repeat the geometry of the neoplasm. The disadvantages include: the duration of the session is up to 40-50 minutes (during this time, the probability of displacement of the patient increases and the risk of changing the relative location and geometry of the pelvic organs), as well as a small uniformity in the distribution of dosage in the focus.
- CTD on a linear accelerator using RapidArc and VMAT technology is characterized by a short duration of the session (4-6 minutes), comfort for the patient, and uniform distribution of the dosage in the focus of the disease.
- STLT is used when a patient can be attributed to a low or intermediate-risk group, provided that the malignant process has not gone beyond the prostate: during instrumental examinations, no data on regional lymph node damage was obtained, and there are no Mr signs that the process has gone beyond the gland capsule.
It should be said that of all the radical methods of treating prostate cancer, STLT is the only non-invasive technique and is often chosen if the patient cannot be treated with other methods due to the presence of contraindications.
When determining the PSA level after irradiation, 3 important factors must be taken into account:
Ionizing radiation destroys the tumor cells in the prostate. This may at the first stage be accompanied by a temporary increase in the PSA, compared to the initial value. Therefore, it is necessary to make a control analysis after irradiation no earlier than 3 months after its end. Further PSA level determinations are performed once every 3 months for several years.
The process of lowering PSA after irradiation can take a long time, in contrast to radical prostatectomy: by the end of the first month after surgery, the PSA level usually reaches the lowest value. This is because the preserved prostate gland continues to produce a small amount of PSA. In medicine, cases have been described when, after irradiation, the PSA level gradually decreased over 5 years of observation. 30% of patients after radiation exposure may have periods of PSA increase during follow-up. This phenomenon is called "benign relapse" or "biochemical leap". The marker level increases very slightly (up to several tenths of ng/ml) and temporarily. This process is based on the same idea that the prostate is preserved and produces a small amount of PSA. This is usually observed in patients with adenoma and a large volume of the gland.
Survival rates determine the effectiveness not only of radiation but also of other radical methods of treatment for prostate cancer. According to numerous studies, the main factor affecting the survival of patients after radiation exposure is the amount of dose applied to the prostate gland. According to today's views, the dose should be from 72 G.
Old methods of irradiation did not allow to affect the prostate in these doses without a strong negative effect on the nearby organs. This explains the relatively small number of patients who chose radiation as a treatment method.
Modern methods make it possible to bring to the prostate doses that exceed 90 Gy. The level of radiation complications is low. Therefore, equal or superior survival rates are provided compared to surgical intervention.
About the main
You need to be clear that in most cases, a diagnosis of prostate cancer is not a verdict. If you promptly consult a doctor in a specialized cancer clinic, which uses all modern methods of radical therapy, the probability of a full recovery is approximately 90%.