Initial analysis of Pro-Qura: A multi-institutional database of prostate brachytherapy dosimetry Gregory S. Merrick 1,2, * , Peter D. Grimm 3,4 , John Sylvester 3,4 , John C. Blasko 3,4 , Wayne M. Butler 1,2 , Zachariah A. Allen 1,2 , Usman-Ul-Haq Chaudhry 1 , Anthony Mazza 1,2 , Mike Sitter 3,4 1 Schiffler Cancer Center, Wheeling Hospital, Wheeling, WV 2 Wheeling Jesuit University, Wheeling, WV 3 Seattle Prostate Institute, Seattle, WA 4 ProQura, Seattle, WA ABSTRACT PURPOSE: The study aimed to analyze the Pro-Qura database in terms of patient implant se- quence number for each institution to determine evidence for a dosimetric learning curve. METHODS AND MATERIALS: In the Pro-Qura database, 2833 of a total of 4614 postplans from 57 brachytherapists were analyzed for evidence of a dosimetric learning curve. The median time between implant and postimplant CT scan was 30 days. I-125 was used in 2123 patients (1687 monotherapy and 536 boost) and Pd-103 in 710 patients (367 monotherapy and 343 boost). Preimplant prostate volume was 35.3 and 32.9 cm 3 in the I-125 and Pd-103 cohorts, respectively. The mean I-125 seed activity was 0.32 and 0.26 mCi for monotherapy and boost, whereas for Pd-103 the mean seed activity was 1.59 and 1.27 mCi, respectively. Postimplant dosimetry was per- formed in a standardized fashion by overlaying the preimplant ultrasound and the postimplant CT scan. Criteria for implant adequacy included a D 90 O90% and a V 100 O 80% for both isotopes. An adequate V 150 was defined as !60% for I-125 and !75% for Pd-103. RESULTS: The mean V 100 and D 90 were 88.9% and 101.9% of prescription dose, respectively. When analyzed in terms of patient sequence number for each institution, the mean V 100 for the first 10 patients was 87.4% and increased to 88.6% for patients 11e20 ( p 5 0.036). Similarly, the mean D 90 for the first 10 patients was 98.9%, whereas for the second cohort of 10 patients the mean D 90 increased to 102.2% ( p 5 0.001). In terms of mean V 100 and D 90 , there was minimal further change for subsequent 10 patient institutional groupings of patient sequence numbers. For the first 10 cases, 27.2% were deemed ‘‘too cool’’ (V 100 !80% and/or D 90 ! 90%). Approximately 16% of all implants were deemed ‘‘too hot’’ (D 90 O 140% or V 150 O 60% for I-125 or O 75% for Pd-103). CONCLUSIONS: Although a learning curve exists for prostate brachytherapy, high-quality bra- chytherapy is achievable in approximately 75e80% of patients treated at community centers. Ó 2007 American Brachytherapy Society. All rights reserved. Keywords: Prostate brachytherapy; Quality; Dosimetry; Pd-103; I-125 Introduction Although prostate brachytherapy with or without supple- mental therapies has proven to be an efficacious treatment for early stage prostate cancer, favorable biochemical outcomes and acceptable morbidity profiles are highly dependent on implant quality with multiple investigators documenting the presence of a dosimetric learning curve (1e6). Dosimet- ric quality is directly related to experience, patient selection, treatment planning, and intraoperative execution (6, 7). De- spite uniform prescribed doses, substantial variability and target volume, seed strength, dose homogeneity, and treat- ment margins have been reported (7). Standardization of pre- implant dosimetry may result in more consistent postimplant dosimetric outcomes (8). The American Brachytherapy Received 21 July 2006; received in revised form 24 October 2006; accepted 29 October 2006. * Corresponding author. Schiffler Cancer Center, Wheeling Hospital, 1 Medical Park, Wheeling, WV 26003-6300, USA. Tel.: þ1-304-243-3490; fax: þ1-304-243-5047. E-mail address: gmerrick@urologicresearchinstitute.org (G.S. Merrick). 1538-4721/07/$ e see front matter Ó 2007 American Brachytherapy Society. All rights reserved. doi:10.1016/j.brachy.2006.10.002 Brachytherapy 6 (2007) 9e15