Primary cryotherapy for high-grade, clinically localized prostate cancer (PCa) appears to be safe and effective in the short term, researchers concluded.
Using the Cryo On-Line Data (COLD) registry, Kae Jack Tay, MBBS, of Duke University in Durham, N.C., and colleagues identified 300 men with biopsy Gleason score 8 or higher, cT1–2 disease and a PSA level of 50 ng/mL or less. All underwent primary whole-gland cryoablation.
The median follow-up was 18.2 months (mean 28.4 months) and the median biochemical progression-free survival (BPFS) was 69.8 months. The estimated 2- and 5-year BPFS rate was 77.2% and 59.1%, respectively, Dr. Tay’s team reported online ahead of print in the Journal of Endourology. In multivariate analysis, only Gleason score 9 or 10 disease and post-treatment PSA nadir of 0.4 ng/mL or higher were the only variables significantly associated with biochemical progression. Compared with Gleason score 8, Gleason score 9 or 10 disease was associated with a significant 1.9 times increased risk of biochemical progression. Compared with a PSA nadir less than 0.4 ng/mL, a PSA nadir of 0.4 ng/mL or higher was associated with a significant 5.7 times increased risk. Each 0.1 ng/mL increment in PSA nadir conferred an additional 4.5% increased risk of biochemical progression.
At the 12-month follow-up, 90.5% of men were completely continent and 17% were potent. The incidence of rectourethral fistulae and urinary retention requiring intervention beyond temporary catheterization was 1.3% and 3.3%, respectively.
“Cryotherapy is a viable choice for patients with high-grade, localized prostate cancer with acceptable short-term oncological and functional outcomes,” the authors concluded. “In our cohort, completeness of prostate cancer ablation, as determined by post-procedure PSA nadir, appears to be the most important factor in determining BPFS.”
At diagnosis, the men in the study had a mean age of 73.3 years and a median PSA 6.85 ng/mL. Of the 300 men, 122 (40.7%) received neoadjuvant hormonal therapy.
The researchers defined biochemical progression according to Phoenix criteria (nadir PSA plus 2 ng/mL). They defined incontinence as any leak reported by patients to their physicians at the 12-month post-operative visit and potency as the ability to have sexual intercourse with or without erectile aids as determined by physicians at the 12-month post-operative visit.
Dr. Tay and his colleagues acknowledged that their study was limited by a significant loss to follow-up, which resulted in a relatively short median follow-up period.
Another limitation, they pointed out, was that the COLD registry is a database contributed to largely by community urologists. “While the advantage of this is the real-life picture of how contemporary cryotherapy is conducted, for scientific purposes, the lack of a formal protocol may result in significant heterogeneity.”
In addition, although biochemical progression is known to precede metastasis followed by death both in men treated with prostatectomy and radiation, they did not have a sufficiently long follow-up to analyze these outcomes meaningfully, the researchers noted.