Prostate cancer is the most common malignancy among elderly men. With the routine use of prostate-specific antigen (PSA) testing since the 1980s, the incidence of prostate cancer has significantly increased. The diagnosis of prostate cancer is established through prostate biopsy, and several biopsy techniques have been developed in recent years.

Prostate biopsy can be broadly classified into systematic and targeted biopsy techniques. Systematic biopsy is performed under transrectal or transperineal ultrasound guidance without the use of prior imaging. Targeted biopsy techniques include cognitive biopsy, multiparametric magnetic resonance imaging (mpMRI) fusion biopsy, in-bore MRI biopsy, and robotic biopsy.

Cognitive biopsy is defined as the targeting of lesions identified on pre-biopsy imaging, usually multiparametric prostate MRI. MRI-fusion biopsy integrates mpMRI images with real-time ultrasound images, while in-bore biopsy is performed directly under MRI guidance. Although MRI-fusion biopsy is considered the gold standard technique, cognitive biopsy is more commonly used in developing countries due to lower cost and reasonable diagnostic accuracy.

Recently, Ga-68 prostate-specific membrane antigen (PSMA) PET/CT has become the gold standard imaging modality for staging prostate cancer after receiving FDA approval. PSMA is a type II transmembrane protein highly expressed on prostate cancer cells. PSMA PET/CT has high sensitivity and specificity for the detection, staging, and recurrence of prostate cancer.

Currently, multiparametric prostate MRI is commonly used to detect lesions before cognitive biopsy. However, there is no study in the literature evaluating the use of PSMA PET/CT imaging for guiding cognitive prostate biopsy.

In this retrospective single-center study, the investigators aim to compare the effectiveness of Ga-68 PSMA PET/CT and multiparametric prostate MRI as imaging modalities used prior to cognitive prostate biopsy.

This retrospective study will include patients who underwent cognitive prostate biopsy at the Urology Department of Health Sciences University Fatih Sultan Mehmet Training and Research Hospital between 2020 and 2024.

Patient records will be reviewed retrospectively. The collected data will include:

Age PSA levels PSA density Prostate volume Prostate biopsy pathology results mpMRI PIRADS scores Ga-68 PSMA PET/CT imaging reports

Patients will be divided into two groups according to the imaging modality used prior to cognitive prostate biopsy:

Patients evaluated with multiparametric prostate MRI Patients evaluated with Ga-68 PSMA PET/CT

The diagnostic outcomes of cognitive biopsy will be compared between these two imaging modalities.

Since the study is retrospective, it will not require additional procedures, interventions, or costs for patients or the institution.

The study will be conducted at a single center.

Inclusion Criteria:

• Male patients aged 40 years or older
• Patients who underwent cognitive prostate biopsy between 2020 and 2024
• Patients who had pre-biopsy imaging with multiparametric prostate MRI or Ga-68 PSMA PET/CT
• Patients with available prostate biopsy pathology results
• Patients with prostate lesions scored PIRADS 4 or 5 on multiparametric prostate MRI

Exclusion Criteria:

• Patients with incomplete clinical or imaging data
• Patients without available histopathological biopsy results
• Patients who underwent prostate biopsy without pre-biopsy imaging
• Patients with lesions scored PIRADS ≤3 on multiparametric prostate MRI

Only male participants are eligible because the prostate gland is present only in males.

Patients aged ≥40 years who underwent cognitive prostate biopsy for suspected prostate cancer with pre-biopsy imaging using multiparametric prostate MRI or Ga-68 PSMA PET/CT between 2020 and 2024.