Histologic validation of auto-contoured dominant intraprostatic lesions on [18F] DCFPyL PSMA-PET imaging

Ryan Alfano; Glenn S Bauman; Wei Liu; Jonathan D Thiessen; Irina Rachinsky; William Pavlosky; John Butler; Mena Gaed; Madeleine Moussa; Jose A Gomez; Joseph L Chin; Stephen Pautler; Aaron D Ward

doi:10.1016/j.radonc.2020.08.008

Histologic validation of auto-contoured dominant intraprostatic lesions on [¹⁸F] DCFPyL PSMA-PET imaging

Radiother Oncol. 2020 Nov:152:34-41. doi: 10.1016/j.radonc.2020.08.008. Epub 2020 Aug 19.

Authors

Ryan Alfano¹, Glenn S Bauman², Wei Liu³, Jonathan D Thiessen⁴, Irina Rachinsky⁵, William Pavlosky⁶, John Butler⁷, Mena Gaed⁸, Madeleine Moussa⁹, Jose A Gomez¹⁰, Joseph L Chin¹¹, Stephen Pautler¹², Aaron D Ward¹³

Affiliations

¹ Baines Imaging Research Laboratory, London, Canada; London Health Sciences Centre, London, Canada; Western University Department of Medical Biophysics, London, Canada. Electronic address: ralfano2@uwo.ca.
² London Health Sciences Centre, London, Canada; Western University Department of Medical Biophysics, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: glenn.bauman@lhsc.on.ca.
³ London Health Sciences Centre, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: wei.liu@lhsc.on.ca.
⁴ Western University Department of Medical Biophysics, London, Canada; St. Joseph's Health Centre, London, Canada; Western University Department of Medical Imaging, London, Canada. Electronic address: jonathan.thiessen@sjhc.london.on.ca.
⁵ London Health Sciences Centre, London, Canada; Western University Department of Medical Imaging, London, Canada. Electronic address: irina.rachinsky@lhsc.on.ca.
⁶ Western University Department of Medical Imaging, London, Canada. Electronic address: william.pavlosky@sjhc.london.on.ca.
⁷ St. Joseph's Health Centre, London, Canada. Electronic address: jbutler@lawsonimaging.ca.
⁸ Western University Department of Pathology and Laboratory Medicine, London, Canada. Electronic address: mgaed@uwo.ca.
⁹ London Health Sciences Centre, London, Canada; Western University Department of Pathology and Laboratory Medicine, London, Canada. Electronic address: madeleine.moussa@lhsc.on.ca.
¹⁰ London Health Sciences Centre, London, Canada; Western University Department of Pathology and Laboratory Medicine, London, Canada. Electronic address: jose.gomezlemus@lhsc.on.ca.
¹¹ London Health Sciences Centre, London, Canada; Western University Department of Surgery, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: joseph.chin@lhsc.on.ca.
¹² St. Joseph's Health Centre, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: stephen.pautler@sjhc.london.on.ca.
¹³ Baines Imaging Research Laboratory, London, Canada; London Health Sciences Centre, London, Canada; Western University Department of Medical Biophysics, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: award54@uwo.ca.

PMID: 32827589
DOI: 10.1016/j.radonc.2020.08.008

Abstract

Background: PSMA-PET¹ has shown good concordance with histology, but there is a need to investigate the ability of PSMA-PET to delineate DIL² boundaries for guided biopsy and focal therapy planning.

Objective: To determine threshold and margin combinations that satisfy the following criteria: ≥95% sensitivity with max specificity and ≥95% specificity with max sensitivity.

Design, setting and participants: We registered pathologist-annotated whole-mount mid-gland prostatectomy histology sections cut in 4.4 mm intervals from 12 patients to pre-surgical PSMA-PET/MRI by mapping histology to ex-vivo imaging to in-vivo imaging. We generated PET-derived tumor volumes using boundaries defined by thresholded PET volumes from 1-100% of SUV³_max in 1% intervals. At each interval, we applied margins of 0-30 voxels in one voxel increments, giving 3000 volumes/patient.

Outcome measurements: Mean and standard deviation of sensitivity and specificity for cancer detection within the 2D oblique histologic planes that intersected with the 3D PET volume for each patient.

Results and limitations: A threshold of 67% SUV max with an 8.4 mm margin achieved a (mean ± std.) sensitivity of 95.0 ± 7.8% and specificity of 76.4 ± 14.7%. A threshold of 81% SUV max with a 5.1 mm margin achieved sensitivity of 65.1 ± 28.4% and specificity of 95.1 ± 5.2%.

Conclusions: Preliminary evidence of thresholding and margin expansion of PSMA-PET images targeted at DILs validated with histopathology demonstrated excellent mean sensitivity and specificity in the setting of focal therapy/boosting and guided biopsy. These parameters can be used in a larger validation study supporting clinical translation.

Keywords: Dominant intraprostatic lesion; Focal boosting; Guided biopsy; Magnetic resonance imaging; Positron-emission tomography; Prostate cancer.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Humans
Male
Positron Emission Tomography Computed Tomography*
Positron-Emission Tomography
Prostatectomy
Prostatic Neoplasms* / diagnostic imaging
Prostatic Neoplasms* / surgery
Tumor Burden