HIFU Effective for Localized Tumors
One study was of 140 men treated in Germany from 1997-2001 with the Ablatherm prototype and the first generation Ablatherm; all the patients had low- or intermediate-risk prostate cancer. Researchers found that HIFU—which is not yet approved for use in the United States—provided excellent long-term prostate cancer-specific survival.
The men, who had a mean age of 69 years, either were unsuitable for radical prostatectomy or were unwilling to undergo the surgery. The mean follow-up was 6.4 years.The eight-year actuarial overall and cancer-specific survival rates were 83% and 98%, respectively. The ac-tuarial biochemical failure-free survival rate at five years was 73%. The salvage treatment-free survival rate at five and eight years was 86% and 79%, respectively, Andreas Blana, MD, of the University of Regensburg, told colleagues. The five-year actuarial disease-free survival rate (according to 2005 ASTRO criteria) was 63%, but the rate was significantly higher in low-risk patients (68% vs. 58%).
Patients had low-risk prostate cancer if their PSA level was less than 10 ng/mL and they had a Gleason score of 6 or less; they had intermediate-risk cancer if they had a PSA level of 10-15 ng/mL and a Gleason score of 7. Dr. Blana's group defined biochemical failure as PSA nadir plus 2 ng/mL.
In another study, French investigators examined outcomes among 463 men (mean age 69 years) with localized prostate tumors treated with a first-generation HIFU machine. François-Joseph Murat, MD, of Edouard Herriot Hospital in Lyon, reported that the treatment provided local disease control in 84.5% of cases and resulted in a four-year actuarial overall disease-free (combining biochemical and pathological findings) survival rate of 64%.
The rate was inversely related to clinical stage (69% for cT1 vs. 57% for cT2), Gleason score (72% for 6 or less vs. 48% for 7), and PSA level (84% vs. 61% and 56% for PSA less than 4 ng/mL vs. 4.1-10 ng/mL 10.1-15 ng/mL) and risk level (76% vs. 55% for low and intermediate-risk patients).
Dr. Murat presented findings from study of HIFU as a salvage treatment for men who had experienced local relapse following external beam radiation therapy (EBRT) for localized prostate cancer. He and his colleagues studied 167 such patients (mean age 69 years), all of whom had positive prostate biopsies and negative metastatic imaging evaluations.
The mean pre-HIFU PSA level was 6.8 ng/mL. The mean follow-up was 17.5 months. Although the five-year actuarial disease-free survival rate was 17%, the rate was inversely related to pre-EBRT risk. The rates were 51%, 30%, and 9% in low-, intermediate-, and high-risk patients, respectively. Dr. Murat's group concluded that HIFU, in patients with a good initial prognosis, is a viable salvage treatment in this patient population with an acceptable morbidity.For both studies, the researchers defined biochemical failure as the PSA over nadir plus 2 ng/mL (ASTRO 2005) and disease-free as PSA under nadir + 2 ng/mL with negative biopsies and no adjuvant therapy.