Complete high-intensity focused ultrasound in prostate cancer: outcome from the @-Registry.

BACKGROUND: To analyze data on patients with localized prostate cancer who were treated with complete high-intensity focused ultrasound (HIFU) prospectively captured within a voluntary HIFU user database (@-Registry). METHODS: The @-Registry includes data from consecutive patients treated with Ablatherm (EDAP-TMS) HIFU at nine European Centres during the period 1994 and 2009. For this analysis, the data repository was reviewed for information on patients with localized prostate cancer (T1 -- T2) treated with complete (whole-gland) HIFU on the basis of an anterior-posterior prostate height of ≤24 mm and a treated volume >120% of the prostate volume. Patients were regularly followed with PSA measurement and biopsy. Biochemical failure was defined for this study as PSA nadir +2 ngml(-1) (Phoenix definition). Disease-free survival was based on a biopsy, retreatment and biochemical data. Patients were risk group-stratified using the D'Amico classification system. RESULTS: The median follow-up was 2.8 years for the 356 patients included in the analysis. The majority could be classified as either low (44.9%) or intermediate risk (39.6%); 14.6% patients were classified as high risk. The median (mean, s.d.) PSA nadir was 0.11 ng ml(-1) (0.78 and 3.6), achieved at a mean (s.d.) of 14.4 (11.6) weeks after HIFU. Follow-up biopsies on 226/356 (63.5%) patients revealed an overall negative biopsy rate of 80.5% (182/226); there was no statistically significant difference in positive biopsy rate by risk group-stratification. Actuarial freedom from biochemical recurrence at 5 and 7 years according to the Phoenix definition was 85% and 79%, respectively. Disease-free progression rates at 5 and 7 years were 64% and 54%, respectively. CONCLUSIONS: Whole-gland prostate HIFU as primary monotherapy for localized prostate cancer achieves a recurrence-free survival in short-term analysis as assessed by prostate biopsy and serum PSA endpoints in a majority of patients.

Birefringence control for ion-exchanged channel glass waveguides.

We show that at 1.55-mum wavelength the waveguide birefringence of ion-exchanged channel waveguides in glass can be broadly tuned by a potassium and silver double-ion exchange. Two different potassium and silver double-ion-exchange processes are used to make surface waveguides with negligible waveguide birefringence. This process is crucially important in the manufacture of devices for dense wavelength-division multiplexing systems. The dependence of the waveguide birefringence on the channel width is also reported.