Role of 68Ga-PSMA PET/CT in Patients with Recurrent Prostate Cancer and its Comparison with Serum PSA Levels and Gleason Scores

Authors

Syed Rashid-ul- Amin Department of Nuclear Medicine and Molecular Imaging, Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan.
Abdul Hai Department of Nuclear Medicine and Molecular Imaging, Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan.
Haider Ali Department of Nuclear Medicine and Molecular Imaging, Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan.
Najeeb Niamatullah Department of Oncology, Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan.
Altaf Hashmi Department of Urology, Sindh Institute of Urology and Transplantation (SIUT), Karachi, Pakistan.

PSMA-11 labelled Gallium PET/CT scan, Biochemical recurrent carcinoma prostate, Gleason score, PSA level, Non-metastatic prostate cancer, Metastases

Abstract: Background: Biochemical recurrence is seen 27–53% in carcinoma prostate patient after treatment. GS (Gleason score) and

baseline PSA level are predictor of recurrence. Post treatment persistent rising PSA level represent the recurrence and PSMA labelled PET-CT

is important part of imaging workup in these patient.

Objective: To detect the relationship of PSA levels and Gleason score in patients investigated for Gallium-PSMA-11 fused molecular imaging

in biochemical recurrent carcinoma prostate.

Material & Methods: This cross-sectional study was carried out at S.I.U.T Karachi. PSMA-PET/CT scan (September 2017-January 2022) of

patient who had biochemical recurrence and not receiving any cancer specific treatment at least 4-week prior scan were included. PSA level

from lab reports and GS from histopathological report were recorded. Biochemical recurrence were defined as when PSA level > 0.4 ng/ml

(post prostatectomy) or >2.0 ng/ml higher than nadir value after radiotherapy. PET/CT scan of 106 included patients were interpreted by

nuclear physician and radiologist team. SUVmax ? 2.5 considered positive for recurrence. Local recurrences, lymph nodal, osseous and

visceral metastasis were documented. Statistical analysis was done by utilizing IBM SPSS software (version 22.0).

Results: In 88 of 106 patients (83%), Gallium-PSMA-11 PET/CT scan detected at least one lesion characteristic of recurrent PCa. The median

PSA level was 12.1 (.01-892.0) ng/dl. In relating PSA value, it was noted that there was significant difference between lesion positive and

negative PSMA-11 labelled Ga-68 PET/CT scan but not statically significant for GS. Local recurrences seen in 70 patients, whereas lymph

node and osseous metastases were noted in 64 and 52 scans respectively. A PSA value 0.68 ng/ml was determined by utilizing ROC curve and

with AUC of 0.924 (95% CI 0.86-0.98) and will likely predict the positive/negative PSMA-11 Gallium PET/CT scan.

Conclusion: Raised PSA level may predict possibility of positive Ga-PSMA-11 PET/CT scan but there was no relationship noted between GS

and Ga-PSMA-11 PET/CT findings.