Curiethérapie prostatique de haut débit de dose

[Image-guided tumor ablation]

INTRODUCTION

Ablatives techniques for destroying in situ a tumoral process aim tissular necrosis by the application of several physical principles.

MATERIAL AND METHODS

We searched MEDLINE^®, Embase^®, using (MeSH) words; from January 2005 through May 2017, and we looked for all the studies. Investigators graded the strength of evidence in terms of methodology, language and relevance.

RESULTS

Forty-seven articles were analyzed. We described ablative techniques and sorted them in thermal and non-thermal therapies according to the used physical principle and their frequency of use in the urological pathology.

CONCLUSION

Percutaneous ablative therapies are mini-invasive techniques, which have an important role in tumors focal treatment. This article is a review of the ablative therapies and describes their physical principles, their equipment and their recent technological modifications, which have been developed to improve the clinical success of these techniques.

[What is the level of evidence of new techniques in prostate cancer radiotherapy?]

Prostate cancer radiotherapy has evolved from the old 2D technique to conformal, and then to intensity-modulated radiation therapy (IMRT) and stereotactic radiotherapy. At the same time, image-guidance (IGRT) is routinely used. New techniques such as protontherapy or carbontherapy are being developed with the objective of increased efficacy, decreased treatment duration, toxicity or cost. This review summarizes the evidence-based medicine of new technologies in the treatment of prostate cancer.

[Prostate cancer boost using high-dose-rate brachytherapy: impact of the learning curve on the dosimetry]

PURPOSE

To analyse the influence of the learning curve on dosimetric data for high-dose-rate brachytherapy prostate cancer boost.

PATIENTS AND METHODS

From February 2009 to May 2012, after a first course of external beam radiation therapy (46Gy/23 fractions), 124 patients underwent high-dose-rate brachytherapy boost using Plato™ (Nucletron, an Elekta company, Elekta AB, Stockholm, Sweden). The impact of the learning curve on the dosimetric quality of the prostate implant was assessed. The dosimetric data have been analysed: clinical target volume (CTV), D90 (dose to 90 % of CTV), D100, V100 (part on the CTV receiving 100 % of the dose), V150, V200 and DHI (dose non-homogeneity index). The doses delivered to 0.1, 1 and 2 cm(3) of the rectum and urethra were calculated.

RESULTS

During the study period (39 months), a significant reduction of V150 (P<0.001), V200 (P<0.001), D0.1rectum (P<0.001), D1rectum (P<0.001), D2rectum (P<0.001), D0.1urethra (P<0.001), and D1urethra (P<0.002) was observed associated with a significant degradation of the D90 (P<0.001) but not significant for the V100 (P=0.29) and the D100 (P=0.3).

CONCLUSION

This study confirms that the dosimetric quality of high-dose-rate brachytherapy prostate implant is significantly improved during the learning curve period.

[How to prepare the brachytherapy of the future]

For more than a century, brachytherapy has been a treatment of choice for delivering a high dose in a small volume. However, over the past 15 years, this irradiation technique has stalled. Even so, brachytherapy allows the delivery of the right dose at the right place by dispensing with target volume motion and repositioning. The evolution of brachytherapy can be based on a road-map including at least the following three points: the acquisition of clinical evidence, teaching and valuation of the procedures. The evolution of brachytherapy will be also impacted by technological considerations (end of the production of low dose rate 192 iridium wires). Regarding the evolution toward a personalized treatment, brachytherapy of the future should take its place as a partner of other modern external beam radiation techniques, be performed by experimented actors (physicians, physicists, technicians, etc.) who received adequate training, and be valued in proportion to the delivered medical service.