New implant technique for separation of the seminal vesicle and rectal mucosa for high-dose-rate prostate brachytherapy

High-dose-rate interstitial brachytherapy in combination with androgen deprivation therapy for prostate cancer: are high-risk patients good candidates?

BACKGROUND AND PURPOSE

To evaluate the effectiveness of high-dose-rate interstitial brachytherapy (HDR-ISBT) as the only form of radiotherapy for high-risk prostate cancer patients.

PATIENTS AND METHODS

Between July 2003 and June 2008, we retrospectively evaluated the outcomes of 48 high-risk patients who had undergone HDR-ISBT at the National Hospital Organization Osaka National Hospital. Risk group classification was according to the criteria described in the National Comprehensive Cancer Network (NCCN) guidelines. Median follow-up was 73 months (range 12-109 months). Neoadjuvant androgen deprivation therapy (ADT) was administered to all 48 patients; 12 patients also received adjuvant ADT. Maximal androgen blockade was performed in 37 patients. Median total treatment duration was 8 months (range 3-45 months). The planned prescribed dose was 54 Gy in 9 fractions over 5 days for the first 13 patients and 49 Gy in 7 fractions over 4 days for 34 patients. Only one patient who was over 80 years old received 38 Gy in 4 fractions over 3 days. The clinical target volume (CTV) was calculated for the prostate gland and the medial side of the seminal vesicles. A 10-mm cranial margin was added to the CTV to create the planning target volume (PTV).

RESULTS

The 5-year overall survival and biochemical control rates were 98 and 87 %, respectively. Grade 3 late genitourinary and gastrointestinal complications occurred in 2 patients (4 %) and 1 patient (2 %), respectively; grade 2 late genitourinary and gastrointestinal complications occurred in 5 patients (10 %) and 1 patient (2 %), respectively.

CONCLUSION

Even for high-risk patients, HDR-ISBT as the only form of radiotherapy combined with ADT achieved promising biochemical control results, with acceptable late genitourinary and gastrointestinal complication rates.

High-dose-rate brachytherapy as monotherapy for prostate cancer: technique, rationale and perspective

High-dose-rate (HDR) brachytherapy as monotherapy is a comparatively new brachytherapy procedure for prostate cancer. Although clinical results are not yet mature enough, it is a highly promising approach in terms of potential benefits for both radiation physics and radiobiology. In this article, we describe our technique for monotherapeutic HDR prostate brachytherapy, as well as the rationale and theoretical background, with educational intent.

Needle applicator displacement during high-dose-rate interstitial brachytherapy for prostate cancer

PURPOSE

To introduce an effective ambulatory technique in high-dose-rate interstitial brachytherapy (HDR-ISBT) for prostate cancer, we investigated the displacement distance using our novel calculation method.

METHODS AND MATERIALS

Sixty-four patients treated with HDR-ISBT as monotherapy were examined. Of these, 4, 17, and 43 patients were administered treatment doses of 38 Gy (3 days), 49 Gy (4 days), and 54 Gy (5 days), respectively. For dose administration, we used 776 flexible applicators with a removable template (ambulatory technique). Using CT images, we calculated the relative coordinates of the metal markers and applicators. From these coordinates, to analyze displacement during treatment, we measured the distance between the tip of the needle applicator and the center of gravity of the markers along the average applicator vector.

RESULTS

The median displacement distance for all applicators was 7 mm (range, -14 to 24), and that of each treatment schedule was 4, 6, and 9 mm for 38, 49, and 54 Gy, respectively. Of the 776 applicators, displacement of >10 mm was seen in 198 (26%) applicators and >15 mm in 57 (7%) applicators. Body height (p<0.0001) and anticoagulant usage (p<0.0001) were significant factors influencing displacement.

CONCLUSIONS

We investigated needle applicator displacement using our unique method. Additional cranial margins are necessary if there is no repositioning of the dwell position. CT scanning should be performed daily during treatment for checking the position of the applicator to detect and rectify the issue of displacement.