1. Ultrasound guidance with a planning system makes precise strikes a reality.
Yan Xiang, Department of Urology, Nanjing Gulou Hospital
2. Cryo as initial treatment
The results of cryopreservation as the initial treatment of prostate cancer are not consistent among reports. At present, the efficacy is mainly judged by local cancer tissue residue and PSA changes. We reviewed 17 groups of clinical reports with a total of 3047 patients with a follow-up time of 3 months to 5.4 years and a median of 6 months. The local tumor residual rate ranged from 8% to 25% with a mean of 17.38% and the biochemical disease-free survival rate (bDFS) ranged from 14% to 96% with a mean of 52.4%.
In most patients, PSA levels increased sharply and then decreased after cryotherapy, reaching a nadir within 3 months. The largest series reported a group including 590 patients with a follow-up of up to 5.4 years. Using an absolute PSA threshold of 0.5 ng/ml as a marker of failure, the 7-year disease-free survival rate was 61%, 68%, and 61% in low-, intermediate-, and high-risk cases, respectively. Biochemical failure generally rarely occurs 24 to 36 months after treatment .
In patients with prostate cancer whose disease has progressed despite radiation therapy, cryotherapy is an alternative method of seeking to achieve a cure. In one group of 150 patients, 93% of biopsies were negative after cryotherapy and 66% survived without biochemical failure; in another group of 118 patients treated with salvage therapy, 94% of postoperative biopsies were negative and 97% of cases had a minimum PSA of less than 0.5 ng/ml, and 34% of patients maintained this low PSA level at 18.6 months follow-up.
2. Salvage cryotherapy
In patients with prostate cancer that has progressed despite radiation therapy, there are few treatment options available to seek a cure. Cryosurgery is indicated for patients with recurrent prostate cancer without metastases and with lesions confined to the gland. The available data suggest that this treatment is fruitful. In a group of 150 patients who underwent 2 cryo-retreatment cycles, the postoperative biopsy negative rate was 93% and the survival rate without biochemical failure was 66% [24]. Patients with preoperative PSA over 10 ng/ml or biopsies with Gieason score over 8 are prone to recurrence [24].
Twenty-nine patients with prostate cancer at the University of California (Los Angeles, USA) underwent salvage cryotherapy after radiotherapy, and 18 were followed up for 12 months, of which 13 maintained PSA levels below 0.4 ng/ml [30, 41]. Allegheny General Hospital (Pittsburgh, PA, USA) reported that 57% of patients treated with cryotherapy, including those who received salvage therapy, had an undetectable PSA level at 10 years [42].
3. Cross-sectional comparison
In a retrospective analysis by Long et al [27] comparing the efficacy of 3 approaches (external beam radiation [EBRT], brachytherapy and cryo), the risk was similar in the 3 groups (low risk in 75%-85%, 65%-85% and 76% of patients treated with the 3 mentioned treatments, respectively, and high risk in 15%-65%, 0%-58% and 45%, respectively). The 5-year biochemical failure-free rate was 76% in 76 patients who received primarily second-generation cryotherapy, with similar outcomes to the 8 groups of patients who received EBRT and brachytherapy. The incidence of rectourethral fistula was 1% to 9%, 0% to 7% and 0.5% in the cryo-, EBRT and brachytherapy groups, respectively, the incidence of urinary incontinence was 0% to 13%, 0% to 5% and 7.5%, respectively, and the incidence of impotence was 93%, 37% to 70% and 10% to 40%, respectively. It is difficult to determine the merits of these methods, but the advantages of cryotherapy are that it can be repeated, whereas radiation therapy cannot; patients who have failed radiation therapy can be treated with cryotherapy and achieve similar results to the initial treatment.
It is important to note that when patients who have received brachytherapy undergo cryotherapy, the previously implanted particles can interfere with the correct determination of the location of the cryoprobe on imaging; moreover, these patients often have more severe fibrosis present in the prostate, which can make the insertion of the cryoprobe difficult [29].
4.Correct view of the complications of cryotherapy
The key to cryotherapy for prostate cancer is to resolve the contradiction between the thoroughness of tumor removal and adverse effects. With the advancement of imaging monitoring technology and the application of argon-helium ultra-fine cryoprobe, complete cryotherapy has become possible, and the incidence of complications such as urinary incontinence and fistula formation has been greatly reduced. Cryotherapy has been increasingly valued as an alternative treatment for prostate cancer, especially as a salvage measure after the failure of other treatments such as radiotherapy. Compared to radical prostatectomy, which is a salvage treatment, cryosurgery offers the same rate of disease control and a lower complication rate than the latter. With the application of third-generation cryopreservation techniques, the incidence of post-cryopreservation incontinence has been reduced to 8%-9%, and in the hands of experienced cryopreservation surgeons, such complications are even less frequent (<1%); with the use of urethral warmers, the incidence of urethral carrion detachment and stricture has been reduced from 10%-15% to 0%; and the incidence of rectourethral fistula has been almost zero due to the use of TRUS and thermosensors [47 ].