Comparison of 68Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and multi-parametric magnetic resonance imaging (MRI) in the evaluation of tumor extension of primary prostate cancer

Mengxia Chen; Qing Zhang; Chengwei Zhang; Yi-Hua Zhou; Xiaozhi Zhao; Yao Fu; Jie Gao; Bing Zhang; Feng Wang; Xuefeng Qiu; Hongqian Guo

doi:10.21037/tau.2020.03.06

Comparison of ⁶⁸Ga-prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) and multi-parametric magnetic resonance imaging (MRI) in the evaluation of tumor extension of primary prostate cancer

Transl Androl Urol. 2020 Apr;9(2):382-390. doi: 10.21037/tau.2020.03.06.

Authors

Mengxia Chen¹, Qing Zhang¹, Chengwei Zhang¹, Yi-Hua Zhou², Xiaozhi Zhao¹, Yao Fu³, Jie Gao¹, Bing Zhang⁴, Feng Wang⁵, Xuefeng Qiu¹, Hongqian Guo¹

Affiliations

¹ Department of Urology, Drum Tower Hospital, Medical School of Nanjing University, Institute of Urology, Nanjing University, Nanjing 210008, China.
² Departments of Experimental Medicine and Infectious Diseases, Nanjing Drum Tower Hospital, Nanjing University Medical School, Nanjing 210008, China.
³ Department of Pathology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China.
⁴ Department of Radiology, Drum Tower Hospital, Medical School of Nanjing University, Nanjing 210008, China.
⁵ Department of Nuclear Medicine, Nanjing First Hospital, Nanjing Medical University, Nanjing 210006, China.

Abstract

Background: To compare the diagnostic performance of ⁶⁸Ga-prostate-specific membrane antigen positron emission tomography/computed tomography (⁶⁸Ga-PSMA PET/CT) with multi-parametric magnetic resonance imaging (mpMRI) on extracapsular extension (ECE) and seminal vesicle invasion (SVI) in primary prostate cancer and its impact on therapeutic decisions.

Methods: We retrospectively enrolled 54 patients with both PET/CT and mpMRI before radical prostatectomy. Diagnostic performance of mpMRI, PET/CT and their combination (com-MRI/PET) on ECE and SVI on a patient basis were analyzed. The impact of additional PET/CT scanning on therapeutic decisions were presented.

Results: Among the 54 patients, 17 had tumor limited in the prostate gland, 25 only had ECE and 12 patients had both SVI and ECE on pathology. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of ECE were 54%, 94%, 95%, 48% on mpMRI, 78%, 94%, 97%, 67% on PET/CT and 83%, 88%, 94%, 71% on com-MRI/PET. Both PET/CT and com-MRI/PET had a higher sensitivity than mpMRI on ECE diagnosis (78% vs. 54%, P<0.05 and 83% vs. 54%, P<0.05). No difference was observed between PET/CT and com-MRI/PET (78% vs. 83%, P=0.17). The Sensitivity, specificity, PPV and NPV of SVI were 67%, 93%, 72%, 91% on mpMRI, 75%, 95%, 82%, 93% on PET/CT and 75%, 88%, 64%, 93% on com-MRI/PET. No difference was found between the three scannings. After the additional evaluation of PET/CT, 18.5% (10/54) turned from nerve-sparing surgery to non-nerve sparing surgery.

Conclusions: ⁶⁸Ga-PSMA PET/CT has a higher sensitivity on ECE detection than mpMRI but shows no superiority on SVI.

Keywords: 68Ga-prostate-specific membrane antigen positron emission tomography/computed tomography (68Ga-PSMA PET/CT); extracapsular extension (ECE); multi-parametric magnetic resonance imaging (mpMRI); prostate cancer; seminal vesicle invasion (SVI).