Evaluation of whole-body tumor burden with 68Ga-PSMA PET/CT in the biochemical recurrence of prostate cancer
68 Ga-PSMA-PET has an increasing importance in the evaluation of prostate cancer patients due to its high sensitivity and specificity in identifying neoplastic lesions in the clinical setting of elevated prostate-specific antigen (PSA). The objective of this study was to calculate the whole-body tumor burden using volumetric quantification of lesions detected in 68Ga-PSMA-PET of prostate cancer patients with biochemical recurrence and correlate these findings with clinical and image parameters.
Each patient had their 68Ga-PSMA-PET analyzed for the presence of neoplastic lesions. Their PSA levels and clinical information were recorded. In positive cases, the tumor burden (TL-PSMA) was calculated with a semi-automatic software and manually, and the results are analyzed and tested.
We analyzed 100 prostate cancer patients, mean age of 69.9 ± 9.7 years and a median PSA of 1.73 ng/dL. 68Ga-PSMA-PET identified neoplastic lesions in 72% of them. The median TL-PSMA was 55.95 ml (1.1–28,080 ml). TL-PSMA and PSA were strongly correlated (rho = 0.71, p < 0.0001, 95% CI 0.60–0.80). TL-PSMA and PSA levels groups had a significant correlation and TL-PSMA and Gleason score were independent variables associated with PSA levels (p < 0.05).
TL-PSMA strongly and independently correlates with PSA levels in prostate cancer patients and could be used as a biomarker to separate them into groups with high or low tumor burden, instead of considering only the number of lesions.
KeywordsPET/CT PSMA PSA Prostate cancer Tumor burden
We thank the Real Nuclear team for their support during this project.
None. This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
The local Institutional Review Board approved this study. Since this was a retrospective study with secondary data, the Local Ethics Committee did not request individual informed consent. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
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