Favorable toxicity and biochemical control using real-time inverse optimization technique for prostate brachytherapy

Raben, Adam; Rusthoven, Kyle E.; Sarkar, Abrihup; Glick, Andrew; Benge, Bruce; Jacobs, Dayee; Raben, David

doi:10.1016/j.brachy.2008.12.004

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Volume 8, Issue 3 , Pages 297-303, July 2009

Favorable toxicity and biochemical control using real-time inverse optimization technique for prostate brachytherapy

Adam Raben
- Department of Radiation Oncology, Helen F. Graham Cancer Center, Wilmington, DE
Kyle E. Rusthoven
- Department of Radiation Oncology, University of Colorado Health Sciences Center, Aurora, CO
- Corresponding author. Department of Radiation Oncology, University of Colorado Denver, 1665 North Ursula Street, Suite 1032, Aurora, CO 80045. Tel.: +1-720-848-0100; fax: +1-720-848-0222.
Abrihup Sarkar
- Department of Radiation Oncology, Helen F. Graham Cancer Center, Wilmington, DE
Andrew Glick
- Brandywine Urology Consultants, Wilmington, DE
Bruce Benge
- Brandywine Urology Consultants, Wilmington, DE
Dayee Jacobs
- Department of Radiation Oncology, Helen F. Graham Cancer Center, Wilmington, DE
David Raben
- Department of Radiation Oncology, University of Colorado Health Sciences Center, Aurora, CO

Received 13 October 2008; received in revised form 25 November 2008; accepted 17 December 2008. published online 13 February 2009.

Abstract

Purpose

Favorable dosimetric results have been reported using intraoperative inverse optimization (IO) for permanent prostate brachytherapy. The clinical implications of these improvements in dosimetry are unclear. We review toxicity and early biochemical outcomes for patients implanted using IO technique.

Methods and materials

Between 2001 and 2007, 165 patients received permanent prostate implants using real-time IO and had ≥3 months of followup. Dose constraints for inverse planning were: the prostate volume receiving 100% of the prescription dose [prostate V₁₀₀] was >95%; the dose received by 90% of the gland [prostate D₉₀] was within the 140–180 by dose range; the volume of urethra receiving 150% of the prescription dose [urethra V₁₅₀] was <30%; and the volume of rectal wall receiving 110% of the prescription dose [rectal V₁₁₀] was <1.0cc. Toxicity was prospectively scored using the Radiation Therapy Oncology Group toxicity scale and the International Prostate Symptom Score questionnaire. Biochemical control was determined using the nadir+2ng/mL definition.

Results

Mean followup was 30 months (range, 6–63 months). Risk classification was low risk in 89% and intermediate risk in 11%. Iodine-125 sources were used for 161 implants and palladium-103 sources for four implants. The median number of seeds and total activity implanted were 61 and 999MBq, respectively, for a median prostate volume of 33.6cc. Late GU and GI morbidity was uncommon. Among patients with at least 24 months followup, 16% had persistent Grade 2–3 urinary morbidity. Grade 2 rectal bleeding occurred in 1 patient (0.6%). Biochemical failure has occurred in only 4 patients at last followup.

Conclusions

IO technique for prostate brachytherapy is associated with low rates of late morbidity and excellent early biochemical control. Additionally, the number of seeds and total implanted activity required to achieve a high-quality implant are lower compared with historical controls.

Keywords: Prostate, Seed implant, Inverse planning, Real-time, Toxicity