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Pre-biopsy Prostate-specific Antigen Velocity does not Predict Gleason Score, Tumor Location or Cancer Volume Following Transperineal-template Guided Prostate Mapping Biopsy: Implications for Prostate Brachytherapy Treatment Planning
I. J. Radiation Oncology d Biology d Physics
S334
2368
Volume 72, Number 1, Supplement, 2008
Pre-biopsy Prostate-specific Antigen Velocity does not Predict Gleason Score, Tumor Location or Cancer Volume Following Transperineal-template Guided Prostate Mapping Biopsy: Implications for Prostate Brachytherapy Treatment Planning
N. Bittner1, G. S. Merrick2, K. E. Wallner3, W. M. Butler2, R. L. Anderson2, Z. A. Allen2, E. Adamovich4 1 University of Washington, Seattle, WA, 2Schiffler Cancer Center, Wheeling, WV, 3Puget Sound Healthcare Corporation, Seattle, WA, 4Wheeling Hospital, Dept of Pathology, Wheeling, WV
Purpose/Objective(s): Prostate-specific (PSA) velocity (PSAV) is associated with higher pathologic Gleason scores and greater prostate cancer mortality. In this study, we evaluated the impact of PSAV on prostate cancer diagnosis, Gleason score, tumor location and cancer volume in men undergoing transperineal template-guided mapping biopsy (TTMB). Materials/Methods: From January 2005 through September 2007, 217 patients underwent TTMB. Criteria for inclusion included a persistently elevated PSA and/or the diagnosis of ASAP or high-grade PIN on prior biopsy. The prostate gland was arbitrarily divided into 24 regions and a median of 56 biopsies were obtained per patient. Patients were divided into 3 velocity cohorts by the following change in PSA diagnosis in the year prior to biopsy: # 0.0 ng/mL, 0.1 - 1.9 ng/mL and $2.0 ng/mL. Multiple parameters including PSAV were evaluated as predictors for prostate cancer diagnosis, Gleason score, tumor volume and cancer location. Results: The mean patient age was 64.5 years with a mean pre-biopsy PSA of 8.3. Prostate cancer was diagnosed in 124 patients (50.6%). When stratified by PSAV, an increase of $2.0 ng/mL was statistically associated with older age, a higher pre-biopsy PSA, a higher PSA density, a greater transition zone index, and were least likely to have a prior biopsy diagnosis of ASAP or PIN. No other differences were discerned between the 3 cohorts. PSAV did not predict for prostate cancer diagnosis (p = 0.317), Gleason score (p = 0.757), the number of positive cores (p = 0.083) or tumor location (p = 0.423). In multivariate analysis, prostate cancer diagnosis was best predicted by pre-biopsy diagnosis, the total number of prior biopsy cores and the transition zone. Gleason score was best predicted by transition zone volume, while prostate cancer volume was most closely related to patient age, total biopsy cores and the transition zone. PSAV did not predict for any of the evaluated parameters. Conclusions: In patients undergoing transperineal template-guided mapping biopsy, pre-biopsy PSAV did not correlate with prostate cancer, grade, volume or location. Although in prostate brachytherapy patients, supplemental external beam radiation therapy to the pelvic lymph nodes and/or androgen deprivation therapy may be indicated in patients with a greater PSAV, intraprostatic brachytherapy dose distributions should not be altered. Author Disclosure: N. Bittner, None; G.S. Merrick, None; K.E. Wallner, None; W.M. Butler, None; R.L. Anderson, None; Z.A. Allen, None; E. Adamovich, None.
2369
Quantifying Respiratory-induced Prostate Motion using Continuous Real-time Tracking Technology
T. L. McDonald, L. Ku, K. M. O’Donnell, D. Kaurin, P. J. Gagnon, C. R. Thomas, A. Y. Hung, M. Fuss Oregon Health & Science University, Portland, OR Purpose/Objective(s): Prostate positional variability can alter the effectiveness of radiation therapy when precise target location is unknown. Traditionally, PTV margins are designed to compensate for inter-fraction prostate setup variability. PTV margins may be reduced when using daily image-guidance. More recently, the dosimetric relevance of intra-fraction prostate motion has been recognized, and may be compensated for by continuous real-time adaptive radiation therapy afforded by the Calypso 4D Localization SystemÔ. As of today, sparse data is available regarding the magnitude and clinical relevance of high-frequency respiratory-induced prostate motion. The specific aim of this analysis was to quantify respiratory-induced prostate motion using electromagnetic continuous real-time tracking technology. Materials/Methods: In twenty patients, prostate motion during radiation delivery was measured using the Calypso System. Prior to radiotherapy planning, three beacon transponders were implanted in the prostate and used for daily localization and continuous realtime positional tracking. Motion tracking reports were generated electronically. Respiratory motion was cross-verified using the clinically tested Varian Real Time Position Management SystemÔ (RPM system). Four hundred fifty motion traces were analyzed. Results: Ninety-five percent of analyzed real-time motion tracking traces demonstrated identifiable respiratory-induced prostate motion (high-frequency motion .0.5 mm). The observed frequency of respiration motion correlated with the respiration frequency derived from the RPM system. The frequency and magnitude of prostate respiratory motion was found to be patient specific and relatively consistent over a course of external beam radiation. Cranio-caudal prostate respiration motion was largest, followed by anterior-posterior movement. Respiratory-induced lateral motion never exceeded 0.5 mm. In 14 patients respiratory-induced prostate motion exceeded 1 mm over 75% of the time (mean 1.3 mm). The largest measured amplitude of respiratory motion was 2.5 mm. Conclusions: Electromagnetic prostate positional tracking during continuous real-time adaptive radiation therapy delivery allowed identifying respiratory-induced high-frequency intra-fraction prostate motion. The observed respiratory-induced motion was larger than previously reported in the literature, where maximum motion of less than 1 mm was described. While the observed motion was small relative to the inter-fraction setup variability of the prostate, individual respiratory-related prostate motion of up to 2.5 mm should be considered when using very narrow PTV safety margins for prostate external beam radiation treatment. Author Disclosure: T.L. McDonald, None; L. Ku, None; K.M. O’Donnell, None; D. Kaurin, None; P.J. Gagnon, None; C.R. Thomas, None; A.Y. Hung, None; M. Fuss, None.
2370
High Dose Rate Brachytherapy Boost for Prostate Cancer: Comparison of Two Different Fractionation Schemes
T. Kaprealian, V. Weinberg, J. Speight, A. R. Gottschalk, M. Roach III, K. Shinohara, I. J. Hsu University of California San Francisco, San Francisco, CA Purpose/Objective(s): A retrospective review of our experience and outcomes using high-dose-rate (HDR) brachytherapy boost for prostate cancer comparing two different fractionation schemes: 600 cGy x 3 (Group 1) compared with 950 cGy x 2 (Group 2).
S334
2368
Volume 72, Number 1, Supplement, 2008
Pre-biopsy Prostate-specific Antigen Velocity does not Predict Gleason Score, Tumor Location or Cancer Volume Following Transperineal-template Guided Prostate Mapping Biopsy: Implications for Prostate Brachytherapy Treatment Planning
N. Bittner1, G. S. Merrick2, K. E. Wallner3, W. M. Butler2, R. L. Anderson2, Z. A. Allen2, E. Adamovich4 1 University of Washington, Seattle, WA, 2Schiffler Cancer Center, Wheeling, WV, 3Puget Sound Healthcare Corporation, Seattle, WA, 4Wheeling Hospital, Dept of Pathology, Wheeling, WV
Purpose/Objective(s): Prostate-specific (PSA) velocity (PSAV) is associated with higher pathologic Gleason scores and greater prostate cancer mortality. In this study, we evaluated the impact of PSAV on prostate cancer diagnosis, Gleason score, tumor location and cancer volume in men undergoing transperineal template-guided mapping biopsy (TTMB). Materials/Methods: From January 2005 through September 2007, 217 patients underwent TTMB. Criteria for inclusion included a persistently elevated PSA and/or the diagnosis of ASAP or high-grade PIN on prior biopsy. The prostate gland was arbitrarily divided into 24 regions and a median of 56 biopsies were obtained per patient. Patients were divided into 3 velocity cohorts by the following change in PSA diagnosis in the year prior to biopsy: # 0.0 ng/mL, 0.1 - 1.9 ng/mL and $2.0 ng/mL. Multiple parameters including PSAV were evaluated as predictors for prostate cancer diagnosis, Gleason score, tumor volume and cancer location. Results: The mean patient age was 64.5 years with a mean pre-biopsy PSA of 8.3. Prostate cancer was diagnosed in 124 patients (50.6%). When stratified by PSAV, an increase of $2.0 ng/mL was statistically associated with older age, a higher pre-biopsy PSA, a higher PSA density, a greater transition zone index, and were least likely to have a prior biopsy diagnosis of ASAP or PIN. No other differences were discerned between the 3 cohorts. PSAV did not predict for prostate cancer diagnosis (p = 0.317), Gleason score (p = 0.757), the number of positive cores (p = 0.083) or tumor location (p = 0.423). In multivariate analysis, prostate cancer diagnosis was best predicted by pre-biopsy diagnosis, the total number of prior biopsy cores and the transition zone. Gleason score was best predicted by transition zone volume, while prostate cancer volume was most closely related to patient age, total biopsy cores and the transition zone. PSAV did not predict for any of the evaluated parameters. Conclusions: In patients undergoing transperineal template-guided mapping biopsy, pre-biopsy PSAV did not correlate with prostate cancer, grade, volume or location. Although in prostate brachytherapy patients, supplemental external beam radiation therapy to the pelvic lymph nodes and/or androgen deprivation therapy may be indicated in patients with a greater PSAV, intraprostatic brachytherapy dose distributions should not be altered. Author Disclosure: N. Bittner, None; G.S. Merrick, None; K.E. Wallner, None; W.M. Butler, None; R.L. Anderson, None; Z.A. Allen, None; E. Adamovich, None.
2369
Quantifying Respiratory-induced Prostate Motion using Continuous Real-time Tracking Technology
T. L. McDonald, L. Ku, K. M. O’Donnell, D. Kaurin, P. J. Gagnon, C. R. Thomas, A. Y. Hung, M. Fuss Oregon Health & Science University, Portland, OR Purpose/Objective(s): Prostate positional variability can alter the effectiveness of radiation therapy when precise target location is unknown. Traditionally, PTV margins are designed to compensate for inter-fraction prostate setup variability. PTV margins may be reduced when using daily image-guidance. More recently, the dosimetric relevance of intra-fraction prostate motion has been recognized, and may be compensated for by continuous real-time adaptive radiation therapy afforded by the Calypso 4D Localization SystemÔ. As of today, sparse data is available regarding the magnitude and clinical relevance of high-frequency respiratory-induced prostate motion. The specific aim of this analysis was to quantify respiratory-induced prostate motion using electromagnetic continuous real-time tracking technology. Materials/Methods: In twenty patients, prostate motion during radiation delivery was measured using the Calypso System. Prior to radiotherapy planning, three beacon transponders were implanted in the prostate and used for daily localization and continuous realtime positional tracking. Motion tracking reports were generated electronically. Respiratory motion was cross-verified using the clinically tested Varian Real Time Position Management SystemÔ (RPM system). Four hundred fifty motion traces were analyzed. Results: Ninety-five percent of analyzed real-time motion tracking traces demonstrated identifiable respiratory-induced prostate motion (high-frequency motion .0.5 mm). The observed frequency of respiration motion correlated with the respiration frequency derived from the RPM system. The frequency and magnitude of prostate respiratory motion was found to be patient specific and relatively consistent over a course of external beam radiation. Cranio-caudal prostate respiration motion was largest, followed by anterior-posterior movement. Respiratory-induced lateral motion never exceeded 0.5 mm. In 14 patients respiratory-induced prostate motion exceeded 1 mm over 75% of the time (mean 1.3 mm). The largest measured amplitude of respiratory motion was 2.5 mm. Conclusions: Electromagnetic prostate positional tracking during continuous real-time adaptive radiation therapy delivery allowed identifying respiratory-induced high-frequency intra-fraction prostate motion. The observed respiratory-induced motion was larger than previously reported in the literature, where maximum motion of less than 1 mm was described. While the observed motion was small relative to the inter-fraction setup variability of the prostate, individual respiratory-related prostate motion of up to 2.5 mm should be considered when using very narrow PTV safety margins for prostate external beam radiation treatment. Author Disclosure: T.L. McDonald, None; L. Ku, None; K.M. O’Donnell, None; D. Kaurin, None; P.J. Gagnon, None; C.R. Thomas, None; A.Y. Hung, None; M. Fuss, None.
2370
High Dose Rate Brachytherapy Boost for Prostate Cancer: Comparison of Two Different Fractionation Schemes
T. Kaprealian, V. Weinberg, J. Speight, A. R. Gottschalk, M. Roach III, K. Shinohara, I. J. Hsu University of California San Francisco, San Francisco, CA Purpose/Objective(s): A retrospective review of our experience and outcomes using high-dose-rate (HDR) brachytherapy boost for prostate cancer comparing two different fractionation schemes: 600 cGy x 3 (Group 1) compared with 950 cGy x 2 (Group 2).