Recommendations for stereotactic body radiation therapy for spine and non-spine bone metastases. A GETUG (French society of urological radiation oncolgists) consensus using a national two-round modified Delphi survey

Background and purpose

The relevance of metastasis-directed stereotactic body radiation therapy (SBRT) remains to be demonstrated through phase III trials. Multiple SBRT procedures have been published potentially resulting in a disparity of practices. Therefore, the french society of urological radiation oncolgists (GETUG) recognized the need for joint expert consensus guidelines for metastasis-directed SBRT in order to standardize practice in trials carried out by the group.

Materials and methods

After a comprehensive literature review, 97 recommendation statements were created regarding planning and delivery of spine bone (SBM) and non-spine bone metastases (NSBM) SBRT. These statements were then submitted to a national online two-round modified Delphi survey among main GETUG investigators. Consensus was achieved if a statement received ≥ 75 % agreements, a trend to consensus being defined as 65-74 % agreements. Any statement without consensus at round one was re-submitted in round two.

Results

Twenty-one out of 29 (72.4%) surveyed experts responded to both rounds. Seventy-five statements achieved consensus at round one leaving 22 statements needing a revote of which 16 achieved consensus and 5 a trend to consensus. The final rate of consensus was 91/97 (93.8%). Statements with no consensus concerned patient selection (3/19), dose and fractionation (1/11), prescription and dose objectives (1/9) and organs at risk delineation (1/15). The voting resulted in the writing of step-by-step consensus guidelines.

Conclusion

Consensus guidelines for SBM and NSBM SBRT were agreed upon using a validated modified Delphi approach. These guidelines will be used as per-protocole recommendations in ongoing and further GETUG clinical trials.

Salvage reirradiation for local prostate cancer recurrence after radiation therapy. For who? When? How?

PURPOSE

Literature review reporting results of salvage brachytherapy and stereotactic body radiotherapy for prostate recurrence only after radiotherapy for prostate cancer.

MATERIALS AND METHODS

A total of 38 studies (including at least 15 patients per study) were analysed: 19 using low-dose-rate brachytherapy, nine high-dose-rate brachytherapy and ten stereotactic body radiotherapy. Only five studies were prospective. The median numbers of patients were 30 for low-dose-rate brachytherapy, 34 for high-dose-rate brachytherapy, and 30 for stereotactic body radiotherapy. The median follow-up were 47months for low-dose-rate brachytherapy, 36months for high-dose-rate brachytherapy and 21months for stereotactic body radiotherapy.

RESULTS

Late genitourinary toxicity rates ranged, for grade 2: from 4 to 42% for low-dose-rate brachytherapy, from 7 to 54% for high-dose-rate brachytherapy and from 3 to 20% for stereotactic body radiotherapy, and for grade 3 or above: from 0 to 24% for low-dose-rate brachytherapy, from 0 to 13% for high-dose-rate brachytherapy and from 0 to 3% for grade 3 or above (except 12% in one study) for stereotactic body radiotherapy. Late gastrointestinal toxicity rates ranged, for grade 2: from 0 to 6% for low-dose-rate brachytherapy, from 0 to 14% for high-dose-rate brachytherapy and from 0 to 11% for stereotactic body radiotherapy, and for grade 3 or above: from 0 to 6% for low-dose-rate brachytherapy, and from 0 to 1% for high-dose-rate brachytherapy and stereotactic body radiotherapy. The 5-year biochemical disease-free survival rates ranged from 20 to 77% for low-dose-rate brachytherapy and from 51 to 68% for high-dose-rate brachytherapy. The 2- and 3-year disease-free survival rates ranged from 40 to 82% for stereotactic body radiotherapy. Prognostic factors of biochemical recurrence have been identified.

CONCLUSION

Despite a lack of prospective data, salvage reirradiation for prostate cancer recurrence can be proposed to highly selected patients and tumours. Prospective comparative studies are needed.

[Toxicity and quality of life comparison of iodine 125 brachytherapy and stereotactic radiotherapy for prostate cancers]

Quality of life is a major issue for good prognostic prostate cancer, for which brachytherapy is one of the reference treatments. Stereotactic Body Radiotherapy (SBRT) is a recent alternative however not yet validated as a standard treatment. This review of the literature reports and compares the toxicities and the quality of life, either after exclusive brachytherapy with iodine 125 or after SBRT. The comparison is made with the limitations of the absence of randomized trial comparing the two treatment techniques. Acute toxicity appears to be lower after SBRT compared to brachytherapy (from 10 to 40 % versus 30 to 40 %, respectively). Conversely, acute and late gastrointestinal toxicity (from 0 to 21 % and from 0 to 10 % of grade 2, respectively) appears more frequent with SBRT. Late urinary toxicity seems identical between both techniques (from 20 to 30 % of grade 2), with a possible urinary flare syndrome. Both treatments have an impact on erectile dysfunction, although it is not possible to conclude that a technique is superior because of the limited data on SBRT. SBRT has better bowel and urinary (irritation or obstruction) quality of life scores than brachytherapy; while sexual and urinary incontinence remain the same. The absence of randomized trial comparing SBRT with brachytherapy for prostate cancers does not allow to conclude on the superiority of one technique over another, thus justifying a phase III medicoeconomic evaluation.