Six years' experience with high-intensity focused ultrasonography for prostate cancer: oncological outcomes using the new 'Stuttgart' definition for biochemical failure

Study Type – Therapy (outcomes research) Level of Evidence 2b

OBJECTIVE

? To determine oncological outcomes after high‐intensity focused ultrasonography (HIFU) treatment in patients with localized prostate cancer using a new, more accurate, definition (‘Stuttgart’ definition) of biochemical failure.

PATIENTS AND METHODS

? We performed a retrospective review of all patients in our centre who received first‐line treatment with a second‐generation Ablatherm^TM device (EDAP‐TMS, Lyon, France). ? Oncological failure was given either by biochemical failure (prostate‐specific antigen, PSA, nadir plus 1.2 g/mL) (Stuttgart definition) or the start of salvage therapy because of a persistently positive biopsy after the HIFU procedure. ? The 5‐year biochemical‐free survival rate and 5‐year disease‐free survival rate were calculated.

RESULTS

? In total, 53 patients were included (mean age, 72.5 ± 4.5 years, range 60–79 years; 28 low risk and 25 intermediate risk). None had undergone previous hormonal therapy. Mean ±sd follow‐up was 45.4 ± 15.5 months (range 16–71 years). Mean (range) pre‐treatment PSA was 8.5 ± 4 (0.29–18) ng/mL. The median (range) PSA nadir value was 1 (0.01–14) ng/mL and occurred after a mean (range) of 5.09 (3–24) months. ? Overall, 36 patients (67.9%) experienced oncological failure. ? These included 33 cases (62.2%) of biochemical failure. A PSA nadir of ≤0.2, 0.21–1.0 and >1 ng/mL was reached in 20.8%, 30.2% and 49% of patients, respectively, and was associated with biochemical failure in 9.1%, 30.3% and 60.6%, respectively. ? The 5‐year biochemical‐free survival rate and disease‐free survival rate were 21.7% and 13.5%, respectively. In multivariate analysis, a PSA nadir of >1 ng/mL was significantly associated with a risk of biochemical and oncological failure (P= 0.002 and P < 0.001). ? Oncological failure was not associated with any risk group. ? No patient died from prostate cancer.

CONCLUSIONS

? In our experience, Ablatherm^TM treatment for clinically localized prostate cancer was associated with a high rate of biochemical failure as determined by the ‘Stuttgart’ definition, and did not achieve effective cancer control. ? The PSA nadir value after HIFU treatment was a significant predictor of treatment failure.