Seed implant brachytherapy for prostate cancer
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* Juanita Crook
* Himu Lukka

We appreciate Ross Halperin's insightful comments on our review of the evidence for brachytherapy in clinically localized prostate cancer.1 He is absolutely correct that there is a lack of level 1 evidence from a properly conducted randomized clinical trial. We hope that the soon-to-be-open cooperative randomized trial from the American College of Surgeons Oncology Group (trial Z0070) and the National Cancer Institute of Canada (trial PR10) comparing radical prostatectomy and permanent seed brachytherapy will eventually provide the evidence that is currently lacking. This cooperative trial has been named SPIRIT (Surgical Prostatectomy v. Interstitial Radiation Intervention Trial). Interestingly, the patients who will participate in this large multicentre randomized trial are exactly the same type of patients for whom we suggested that brachytherapy was suitable as monotherapy (with favourable, low-risk T1c or T2a tumours, a Gleason score of 6 or lower and a serum prostate-specific antigen level of 10 μg/L or less). 

Patients at intermediate risk (those with a Gleason score of 7 or a serum prostate-specific antigen level greater than 10 μg/L but less than 20 μg/L) are not a homogeneous group for whom one can make a single recommendation. The evidence suggesting the prognostic factors that will subdivide this group is still very young. As the data mature, recommendations can be revisited and altered appropriately.

## Reference

1.  1. Crook J, Lukka H, Klotz L, Bestic N, Johnston M, and the Genitourinary Cancer Disease Site Group of the Cancer Care Ontario Practice Guidelines Initiative. CMAJ 2001;164(7):975-81.
    
    [Abstract/FREE Full Text](http://www.cmaj.ca/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NDoiY21haiI7czo1OiJyZXNpZCI7czo5OiIxNjQvNy85NzUiO3M6NDoiYXRvbSI7czoyMzoiL2NtYWovMTY1LzgvMTAwNC4xLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==)