Genitourinary Cancer

PD 01 - GU 1 - Poster Discussion - New Data on PET, MRI and Protons for Treating Prostate Cancer

1002 - A Prospective Study of F-18 Fluoro-methyl-choline (FCH) And Ga-68 HBED-CC- (PSMA) in Men being Considered for Salvage Radiation Treatment for Biochemical Failure Post Radical Prostatectomy

Sunday, October 21
1:27 PM - 1:33 PM
Location: Room 217 A/B

A Prospective Study of F-18 Fluoro-methyl-choline (FCH) And Ga-68 HBED-CC- (PSMA) in Men being Considered for Salvage Radiation Treatment for Biochemical Failure Post Radical Prostatectomy
G. S. Bauman1, U. Metser2, A. Scott3, F. Pouliot4, A. Weickhardt3, I. Davis5, R. Hicks6, S. Punwani7, S. Chua8, and L. Emmett9; 1Department of Oncology, Western University, London, ON, Canada, 2Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada, 3Austin Health, Melbourne, Australia, 4Universite Laval, Quebec, QC, Canada, 5Monash University Eastern Health, Melbourne, Australia, 6Peter MacCallum Cancer Centre, Melbourne, Australia, 7University College London Hospital, London, United Kingdom, 8The Royal Marsden NHS Foundation Trust, London, United Kingdom, 9St. Vincent's Hospital, Sydney, Australia

Purpose/Objective(s): Men presenting with rising PSA following radical prostatectomy (RP) may be cured by salvage radiation therapy (SRT) directed to the prostatic fossa (PF). However, a significant proportion of men will not benefit from SRT presumably due to spread of cancer outside the PF not detected by conventional imaging. The purpose of this study was to evaluate the predictive value of new methods of imaging with FCH and PSMA PET/CT and MRI in identifying men at high risk of having extra-PF disease who are being considered for SRT for biochemical failure after RP.

Materials/Methods: Prospective, multisite, international trial in men post RP with negative or equivocal conventional imaging, high risk features (PSA > 0.2ng/ml and >GSC 7 or PSA doubling time <10 months, or PSA >1.0ng/ml) and rising PSA being considered for SRT. 91 eligible enrolled men underwent FCH PET/CT and multi-parametric MRI of the pelvis (mpMRI) within 2 weeks, with additional PSMA PET/CT in (31/91). All imaging was interpreted by two readers. Treatment plan was documented before and after imaging to assess management impact, and all subsequent treatments, biopsies and serial PSA collected. Imaging results were validated using a composite reference standard. Treatment response was defined as a PSA drop of > 50% after SRT only (no concurrent or adjuvant androgen deprivation)

Results: Median PSA at imaging was 0.41±1.2, median Gleason score 8 and median PSA doubling time 5.0 months. By modality, detection rates for any recurrent prostate cancer were (24/89)27%, (29/91)32% and (13/31)43% for mpMRI, FCH PET/CT and PSMA PET/CT respectively. In men with positive scans, extra-PF disease was identified in (11/24) 41% (mpMRI), (17/29) 58% (FCH) and (9/13) 69% (PSMA). Comparing PSMA and FCH imaging, PSMA identified 36 sites of disease (in 13/30 men) compared to 20 sites (in 13/30 men) on FCH (p < 0.005). Imaging findings changed expected management in 46% (42/91) due to FCH, and 23% (21/90) MRI. PSMA provided incremental management change in 7/31 (23%) over FCH. Treatment response to SRT was higher in men with negative or PF confined FCH PET/CT uptake vs. uptake outside the PF (33/45; 72% vs. 3/9; 33%, p< 0.03). Likewise, response was higher in negative or PF confined PSMA PET/CT uptake (7/8; 87% vs. 1/7; 14%, p<0.009).

Conclusion: A high incidence of extra-PF disease was identified with FCH, PSMA and MRI in high risk men with (negative conventional imaging) rising PSA post RP being considered for salvage radiation therapy, with a consequent high management impact. Men with negative or uptake confined to the PF had the highest response rates to salvage RT.

Author Disclosure: G. Bauman: Independent Contractor; London Health Sciences Centre. Chair/Chief of Oncology; London Health Sciences Centre. U. Metser: None. A. Scott: None. F. Pouliot: Investigator; Progenics Inc. A. Weickhardt: None. I. Davis: Research Grant; ANZUP Clinical Trials Group. Fellowship Funding APP1102604; NHMRC. Chair; Pfizer, Astellas Oncology. Member; Novartis, BMS, Roche, Eisai. Nexavar; Bayer. GU Cancer AB; Astra Zeneca. S. Punwani: None. S. Chua: None.

Glenn Stuart Bauman, MD

London Health Sciences Centre

Disclosure:
Employment
London Health Sciences Centre: Radiation Oncologist: Independent Contractor

Leadership
London Health Sciences Centre: Chair/Chief of Oncology

Presentation(s):

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1002 - A Prospective Study of F-18 Fluoro-methyl-choline (FCH) And Ga-68 HBED-CC- (PSMA) in Men being Considered for Salvage Radiation Treatment for Biochemical Failure Post Radical Prostatectomy



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