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A dosimetric analysis of unstranded seeds versus customized stranded seeds in transperineal interstitial permanent
Randy V Heysek1, Clement K Gwede, Javier Torres-Roca
1Radiation Oncology Program, H. Lee Moffitt Cancer Center, University of South Florida, Tampa, FL 33612, USA. heysekrv@moffitt.usf.edu
Purpose:
This study aimed to retrospectively analyze the dosimetric and toxicity results from 272 patients with localized prostate cancer treated consecutively using loose or stranded radioactive seeds by transrectal ultrasound-guided transperineal permanent prostate seed brachytherapy.
Methods And Materials:
Two hundred seventy-two patients with localized prostate cancer treated between February 2002 and June 2004 were analyzed. All patients were treated with radioactive iodine-125 or palladium-103 using unstranded or loose seeds (USS) (159 patients) or customized stranded seeds (CSS) at variable spacing (5-50 mm) (113 patients) (Vari-Strand; BrachySciences, Oxford, CT). A single experienced brachytherapist performed all implants.
Results:
There was a slight improvement in the dosimetric parameter D90 between the CSS (101.9%) and USS (99.3%) groups (p = 0.041). However, overall implant quality based on Radiation Therapy Oncology Group (RTOG) guidelines was similar between both groups.
Conclusions:
We conclude that the D90 value calculated for CSS is statistically improved when compared to the USS cohort, but without a clinically significant difference. There was no difference in the toxicity scores in either group. Overall quality between groups is comparable in our institution.
