Detection of recurrence sites using FCH PET/CT in prostate cancer patients with PSA failure
Dong-Yun Kim,
Korea Republic of
PO-1375
Abstract
Detection of recurrence sites using FCH PET/CT in prostate cancer patients with PSA failure
Authors: Dong-Yun Kim1, Won-Woo Lee2, Seok-Soo Byun3, Jae-Sung Kim4
1Seoul National University Hospital , Radiation Oncology , Seoul, Korea Republic of; 2Seoul National University Bundang Hospital , Nuclear Medicine, Seongnam, Korea Republic of; 3Seoul National University Bundang Hospital , Urology, Seongnam, Korea Republic of; 4Seoul National University Bundang Hospital , Radiation Oncology , Seongnam, Korea Republic of
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Purpose or Objective
The optimal condition for clinical application of 18F-fluorocholine Positron Emission Tomography–Computed Tomography (FCH-PET/CT) to detect recurrence sites in prostate specific antigen (PSA) failure remains unclear due to the heterogeneity of prostate cancer PSA failure. We aimed to evaluate the detection rate of FCH-PET/CT in prostate cancer patients with PSA failure and determine the optimal PSA level to take FCH-PET/CT.
Material and Methods
FCH-PET/CT was conducted in 89 patients diagnosed with PSA failure after radical treatment (radical prostatectomy in 75 and definitive radiotherapy in 14) between November 2018 and May 2021. Detection rates were examined by receiver operating characteristic (ROC) analysis and multivariable logistic regression was performed to identify factors affecting the positive findings on FCH-PET/CT. We also did subgroup analyses according to the response after the radical treatment; persistent high PSA (N=48) and biochemical recurrence (BCR) (N=41).
Results
Of all patients, FDG-PET/CT demonstrated 59.6% of overall detection rates and the optimal PSA threshold for detecting positive findings was ≥ 1.00 ng/ml at the time of imaging. On multivariable analysis, PSA higher than 1.00 ng/ml (P<0.001) was a significant factor to affect detection rates on FCH-PET/CT, especially to find positive findings of distant bone metastases (P<0.001) and recurrence outside the pelvis (P<0.001). In a subgroup analysis of patients with BCR after initial radical treatment, the area under ROC curve was 0.82 and the PSA level of 1.75 ng/ml or higher was the optimal value for positive FDG-PET/CT findings. This PSA value also was correlated with significantly higher distant bone metastases and outside pelvis metastasis detection rates (P<0.001, both respectively).
Conclusion
FCH-PET/CT is a clinically useful tool for detecting tumor recurrence sites in prostate cancer patients with PSA failure if PSA has exceeded a certain value at the time of imaging. In particular, higher AUC values were observed when FCH-PET/CT was performed in patients with BCR after initial treatment.