The use of high-intensity focused ultrasound (HIFU) for the primary treatment of prostate cancer will probably become more common in the very near future. HIFU has been used for many years in Europe and Mexico and has recently been in clinical trials in the United States. HIFU has been a successful method of prostate cancer treatment, so to assume it will obtain FDA approval in the future is not unreasonable.

Like all other primary prostate cancer treatments a certain number of HIFU treatments will fail and the disease will progress, either coming back in what is left of the treated prostate gland remainder and the surrounding tissue (localized) or in other remote body parts (metastatic).

Radiotherapy is an obvious treatment option in the case of local failure following HIFU treatment. However, prior to establishing radiotherapy as a good salvage treatment option there needs to be studies confirming its efficacy. Such study was performed and its results published in the Journal of European Urology.

This study was designed to evaluate tolerance and oncologic control with salvage radiotherapy (SRT) after HIFU failure and to identify predictive factors of success.

It evaluated men who presented with histologically proven, persistent local prostate cancer following HIFU treatment given from March 1995 to March 2008. All the subjects were treated with curative intent (with or without hormonal treatment) and were included in this single-centre retrospective study.

All subjects were treated with conformal radiotherapy. The median dose of conformal treatment was 72 Gy (65-78 Gy).

The primary outcome measure was progression-free survival (PFS) which was defined as no biochemical relapse (three consecutive rises in prostate-specific antigen

[PSA] with a velocity >0.4ng/ml per year or PSA >1.5ng/ml) and no additional treatment.

Predictive factors of failure were examined in univariate and multivariate analysis. Adverse events in terms of urinary and digestive toxicity, urine incontinence, and erectile dysfunction (ED) were also reported.

    RESULTS

*The median (range) and mean (standard deviation) follow-up of the 100 patients analyzed was 33 mo (5-164 mo) and 37.2 mo (23.6 mo), respectively.

*Eighty-three men received SRT alone while 17 received SRT and androgen-deprivation therapy

*For these men the PFS was 72.5% at 5 yr and 93%, 67%, and 55% for the low, intermediate, and high-risk groups.

*In the univariate analysis, PSA level prior to SRT, risk status, PSA nadir after SRT, PSA nadir after SRT >0.2ng/ml, and time to achieve this nadir were all predictive of failure.

*In the multivariate analysis, PSA nadir post-SRT with a threshold at 0.2ng/ml and time to achieve this nadir were the significant predictive factors of failure.

Side effects of the SRT was also recorded. Gastrointestinal toxicity was low; urinary toxicity grade less than or equal to 2 was 34.5%. Four were grade 3 (4.7%), one was grade 4 (1.2%), and one was grade 5 (1.2%). The incidence of severe ED (International Index of Erectile Dysfunction-5 score 5-10) was 14% pre-HIFU, and 51.9% and 82.3% pre- and post-SRT, respectively.

The study authors concluded that SRT provides satisfactory oncologic control after HIFU failure with little (or mild) additional toxicity. The study was retrospective so its conclusions must be interpreted cautiously. These results warrant further investigation.

Eur Urol. 2010 Jun 11; Riviere J, Bernhard JC, Robert G, Wallerand H, Deti E, Maurice-Tison S, Ardiet JM, Maire JP, Richaud P, Ferriere JM, Ballanger P, Gelet A, Pasticier G

PMID: 20598436 [PubMed – as supplied by publisher]

Joel T Nowak, MA, MSW