Accuracy of gross tumour volume delineation with [68Ga]-PSMA-PET compared to histopathology for high-risk prostate cancer

Maryam Zarei; Elin  Wallsten; Josefine  Grefve; Karin Söderkvist; Adalsteinn  Gunnlaugsson; Kristina Sandgren; Joakim Jonsson; Angsana Keeratijarut Lindberg; Erik Nilsson; Anders Bergh; Björn Zackrisson; Mathieu Moreau; Camilla Thellenberg Karlsson; Lars E. Olsson; Anders Widmark; Katrine Riklund; Lennart Blomqvist; Vibeke Berg Loegager; Jan Axelsson; Sara N. Strandberg; Tufve Nyholm

doi:10.2340/1651-226X.2024.39041

Acta Oncologica (Jun 2024)

Accuracy of gross tumour volume delineation with [68Ga]-PSMA-PET compared to histopathology for high-risk prostate cancer

Maryam Zarei,
Elin Wallsten,
Josefine Grefve,
Karin Söderkvist,
Adalsteinn Gunnlaugsson,
Kristina Sandgren,
Joakim Jonsson,
Angsana Keeratijarut Lindberg,
Erik Nilsson,
Anders Bergh,
Björn Zackrisson,
Mathieu Moreau,
Camilla Thellenberg Karlsson,
Lars E. Olsson,
Anders Widmark,
Katrine Riklund,
Lennart Blomqvist,
Vibeke Berg Loegager,
Jan Axelsson,
Sara N. Strandberg,
Tufve Nyholm

Affiliations

Maryam Zarei: ORCiD; Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Elin Wallsten: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Josefine Grefve: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Karin Söderkvist: Department of Diagnostics and Intervention, Oncology, Umeå University, Umeå, Sweden
Adalsteinn Gunnlaugsson: Skane University Hospital, Department of Hematology, Oncology and Radiation Physics, Lund, Sweden
Kristina Sandgren: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Joakim Jonsson: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Angsana Keeratijarut Lindberg: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Erik Nilsson: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Anders Bergh: Department of Medical Biosciences, Pathology, Umeå University, Umeå, Sweden
Björn Zackrisson: Department of Diagnostics and Intervention, Oncology, Umeå University, Umeå, Sweden
Mathieu Moreau: Skane University Hospital, Department of Hematology, Oncology and Radiation Physics, Lund, Sweden
Camilla Thellenberg Karlsson: Department of Diagnostics and Intervention, Oncology, Umeå University, Umeå, Sweden
Lars E. Olsson: Department of Translational Medicine, Medical Radiation Physics, Lund University, Malmö, Sweden
Anders Widmark: Department of Diagnostics and Intervention, Oncology, Umeå University, Umeå, Sweden
Katrine Riklund: Department of Diagnostics and Intervention, Diagnostic Radiology, Umeå University, Umeå, Sweden
Lennart Blomqvist: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden; Department of Molecular Medicine and Surgery, Karolinska Institutet, Solna, Sweden
Vibeke Berg Loegager: Department of Radiology, Copenhagen University Hospital in Herlev, Herlev, Denmark
Jan Axelsson: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden
Sara N. Strandberg: Department of Diagnostics and Intervention, Diagnostic Radiology, Umeå University, Umeå, Sweden
Tufve Nyholm: Department of Diagnostics and Intervention, Biomedical engineering and Radiation Physics, Umeå University, Umeå, Sweden

DOI: https://doi.org/10.2340/1651-226X.2024.39041
Journal volume & issue: Vol. 63, no. 1

Abstract

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Background: The delineation of intraprostatic lesions is vital for correct delivery of focal radiotherapy boost in patients with prostate cancer (PC). Errors in the delineation could translate into reduced tumour control and potentially increase the side effects. The purpose of this study is to compare PET-based delineation methods with histopathology. Materials and methods: The study population consisted of 15 patients with confirmed high-risk PC intended for prostatectomy. [68Ga]-PSMA-PET/MR was performed prior to surgery. Prostate lesions identified in histopathology were transferred to the in vivo [68Ga]-PSMA-PET/MR coordinate system. Four radiation oncologists manually delineated intraprostatic lesions based on PET data. Various semi-automatic segmentation methods were employed, including absolute and relative thresholds, adaptive threshold, and multi-level Otsu threshold. Results: The gross tumour volumes (GTVs) delineated by the oncologists showed a moderate level of interobserver agreement with Dice similarity coefficient (DSC) of 0.68. In comparison with histopathology, manual delineations exhibited the highest median DSC and the lowest false discovery rate (FDR) among all approaches. Among semi-automatic approaches, GTVs generated using standardized uptake value (SUV) thresholds above 4 (SUV > 4) demonstrated the highest median DSC (0.41), with 0.51 median lesion coverage ratio, FDR of 0.66 and the 95th percentile of the Hausdorff distance (HD95%) of 8.22 mm. Interpretation: Manual delineations showed a moderate level of interobserver agreement. Compared to histopathology, manual delineations and SUV > 4 exhibited the highest DSC and the lowest HD95% values. The methods that resulted in a high lesion coverage were associated with a large overestimation of the size of the lesions.

Published in Acta Oncologica

ISSN: 1651-226X (Online)
Publisher: Medical Journals Sweden
Country of publisher: Sweden
LCC subjects: Medicine: Internal medicine: Neoplasms. Tumors. Oncology. Including cancer and carcinogens
Website: https://medicaljournalssweden.se/actaoncologica

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