HIFU-therapy and cryodestruction - minimally invasive prostate cancer treatment

A few years ago in the arsenal of urologist and oncologist for prostate cancer was only bilateral orchidectomy. In the early 1990's, the last century in the US and European countries, the proportion of early cancers has increased significantly, both among young and elderly people.

Increasingly, the patient's opinion influenced the final choice of the method of treatment. Patients should receive full reliable information about possible treatment options and be able to choose. Quite often patients prefer a slightly less effective, but more gentle methods than traumatic prostatectomy. Ego served as an impetus to the development of new effective minimally invasive techniques.

As an alternative to prostatectomy and radiation therapy for localized prostate cancer, cryo-and ultrasonic tumor destruction was proposed. The latter method was included in the recommendations of the Association of Urologists of France, and cryodestruction - in the recommendations of the American Association of Urologists. Both methods are classified as minimally invasive interventions and, theoretically not inferior to surgery and irradiation, are associated with a lower risk of complications.

[1], [2], [3], [4]

Cryodestruction of prostate cancer

The following mechanisms of cell death during freezing are known:

• dehydration associated with protein denaturation;
• rupture of cell membranes by ice crystals;
• slowing of blood flow and thrombosis of capillaries with microcirculatory disturbance and ischemia;
• apoptosis.

Under the control of transrectal ultrasound in the prostate gland, 12-15 needles are introduced to cool the diameter of 17 G. At the level of the neck of the bladder and the external sphincter of the rectum, temperature sensors are installed, a heater is introduced into the urethra. Two cycles of freezing and thawing are carried out (the temperature in the gland thickens and in the region of the neurovascular bundles reaches -40 ° C).

Cryodestruction is better for patients with low oncological risk. The volume of the gland should not exceed 40 cm ³ (otherwise, not to introduce needles for freezing under the pubic symphysis, begin with hormone therapy), the PSA level - no more than 20 ng / ml and the Gleason index - no more than 6. Since the data on the 10- and there are practically no 15-year long-term results, patients with an expected life expectancy of more than 10 years should be informed that the long-term results of the method have not been studied enough.

Speaking about the effectiveness of various new treatments, it must be remembered that the risk of death from localized PCa within 10 years after prostatectomy is only 2.4%.

It is difficult to evaluate the effectiveness of cryodestruction in terms of the dynamics of the PSA content, since the criteria for relapse with different equipment are not the same. For example, with the use of second-generation equipment in a group of 975 patients, 5-year disease-free survival in low, medium and high-risk groups was 60, 45 and 36%, respectively (if the PSA rises to more than 0.5 ng / ml) , 71 and 61% (if relapse is considered to be a PSA level of about 1 ng / ml). The application of the criteria of the American Society of Curative Radiology and Oncology (ASTRO), where recurrence is considered to be three consecutive increases in the G1CA content, demonstrates a 7-year relapse-free survival in 92% of patients.

Cryodestruction with preservation of cavernous nerves is possible when the half of the gland that is affected by the tumor is frozen.

Erection disorders occur in about 80% of patients (regardless of the technique used). When using third generation equipment, tissue rejection occurs in 3% of patients, urinary incontinence - in 4.4, urinary retention - in 2, pain in the lower abdomen - in 1.4% of patients. The risk of urinary fistula development does not exceed 0.2%. About 5% of cases there is obstruction of the urethra, which requires transurethral resection of the prostate gland.

According to the questionnaire, most of the functional disorders caused by cryodestruction take place within a year. In the next two years, no significant change is taking place. Three years after cryodestruction, 37% of patients may have sex life.

Cryodestruction is possible in low- _dose groups (T _1-2a, Gleason score less than 6, PSA level below 10 ng / ml), and medium risk (T _2b PSA level 10-20 ng / ml or Gleason 7 index). The volume of the prostate gland should not exceed 40 cm ³.

Five-year disease-free survival in the low-risk group is cleaner than after prostatectomy, but there are no data on long-term results and this should be reported to patients.

[5], [6], [7], [8]

High-intensity focused ultrasound ablation of the prostate (HIFU-therapy)

Ultrasonic waves of high intensity destroy the tumor with the help of heating and acoustic cavitation. The tumor is heated to 65 ° C, which causes coagulation (dry) necrosis. The procedure is carried out under general or spinal anesthesia, in a position on the side. The destruction of every 10 g of the gland tissue takes about 1 hour.

As in the case of cryodestruction, the interpretation of the results of ultrasonic destruction is complicated by the lack of generally accepted efficiency criteria. In addition, the literature data allow us to judge about studies conducted only for 10 thousand patients.

Virtually all patients have a delay in urine, which requires a catheterization of the bladder for 7-10 days or epicystostomy for 12-35 days. Urinary incontinence of mild or moderate degree during exercise is noted by 12% of patients. To eliminate obstruction of the urethra, transurethral resection of the prostate or dissection of the neck of the bladder is often necessary. Optimal one-stage execution of both procedures is considered. The risk of impotence is 55-70%.

HIFU therapy and cryodestruction may be an alternative to surgery in patients with an expected life expectancy of less than 10 years or when performed at the patient's request.