Preliminary Clinical Practice of Radical Prostatectomy Without Preoperative Biopsy
Prostate cancer (PCa) remains a significant health concern globally, with biopsy being the standard procedure for diagnosis before radical prostatectomy (RP). However, advancements in imaging technologies, such as prostate-specific membrane antigen positron emission tomography/computed tomography (PSMA PET/CT) and multiparametric magnetic resonance imaging (mpMRI), have sparked interest in exploring the feasibility of avoiding preoperative biopsy. This article delves into a study that investigates the potential of performing RP without prior biopsy in patients highly suspected of having PCa based on PSMA PET/CT and mpMRI assessments.
Background and Rationale
Currently, biopsy is indispensable for diagnosing PCa before RP. Despite its necessity, biopsy is associated with several complications, including hematuria, hematospermia, infection, and even sepsis. Moreover, the sensitivity of transrectal ultrasound-guided prostate biopsy is relatively low, often detecting clinically insignificant PCa (cisPCa). These limitations have driven the search for alternative diagnostic pathways that can reduce unnecessary biopsies and their associated risks.
The integration of PSMA PET/CT and mpMRI has shown promise in improving the diagnostic accuracy of PCa. PSMA PET/CT, in particular, has demonstrated high specificity and positive predictive value (PPV) for detecting PCa. Similarly, mpMRI has been shown to enhance the detection of clinically significant PCa (csPCa) compared to traditional biopsy methods. The combination of these imaging modalities could potentially provide a reliable alternative to biopsy in selected patients.
Study Design and Methods
This retrospective two-center study included 56 patients who underwent RP without preoperative biopsy between December 2017 and April 2022. The patients were selected based on elevated prostate-specific antigen (PSA) levels, positive mpMRI results (Prostate Imaging Reporting and Data System [PI-RADS] score ≥4), and positive PSMA PET/CT results (maximum standardized uptake value [SUVmax] ≥4). The study aimed to evaluate the consistency between clinical and pathological diagnoses and assess the feasibility of avoiding biopsy before RP.
All patients underwent mpMRI using either a 3.0T or 1.5T system, with results analyzed by expert radiologists. PSMA PET/CT was performed using various radiotracers, and imaging was analyzed by nuclear medicine specialists. Patients with positive results from both imaging modalities were considered for RP without biopsy after being fully informed of the potential risks and benefits.
Surgical procedures were performed laparoscopically or robot-assisted laparoscopically, and pathological evaluations were conducted according to standardized protocols. The primary outcome was the consistency between clinical and pathological diagnoses, with secondary outcomes including preoperative characteristics, postoperative pathological findings, perioperative complications, and follow-up results.
Results and Findings
Of the 56 patients, 55 (98%) were confirmed to have PCa by pathology, with 49 (89%) having csPCa (ISUP grade ≥2). One patient was diagnosed with high-grade prostatic intraepithelial neoplasia (HGPIN). The median age of the patients was 66.5 years, and the median PSA level was 21.0 ng/mL. The median prostate volume was 37.4 mL, and the median SUVmax was 12.9.
The study found that patients with csPCa had significantly higher PSA levels (22.9 ng/mL vs. 10.0 ng/mL), lower median prostate volumes (32.2 mL vs. 65.0 mL), and higher median SUVmax values (13.3 vs. 5.6) compared to those with cisPCa or HGPIN. Additionally, csPCa patients were more likely to have PI-RADS 5 lesions (69% vs. 14%).
Pathological staging revealed that 21 (38%) patients were at the T2 stage, and 34 (62%) were at the T3 stage. Seminal vesicle invasion (pT3b) was correctly identified in all eight patients by imaging, while extracapsular extension (pT3a) was correctly identified in 81% of cases. No positive lymph nodes were found by pathology.
The median follow-up time was 17.5 months, with 91% of patients achieving a PSA level of less than 0.1 ng/mL within three months post-surgery. Biochemical recurrence occurred in 9% of patients, and all patients regained urinary continence within six months.
Discussion and Implications
The study’s findings suggest that it may be feasible to avoid biopsy before RP in patients with a high probability of PCa based on PSMA PET/CT and mpMRI assessments. The combination of these imaging modalities demonstrated a high PPV for detecting csPCa, particularly when using an SUVmax cut-off of 7.5 or higher, which achieved a 100% PPV.
However, the study also highlighted the limitations of relying solely on imaging for diagnosing csPCa. The diagnostic efficacy of PI-RADS ≥4 and SUVmax ≥4 was inadequate for performing RP without biopsy, as evidenced by the false-positive cases of cisPCa and HGPIN. Therefore, strict patient selection criteria and thorough risk disclosure are essential when considering this biopsy-free pathway.
The advantages of avoiding biopsy before RP include the elimination of biopsy-related complications, reduced surgical difficulty due to the absence of post-biopsy edema, and alleviation of patient anxiety during the waiting period for surgery. However, the role of biopsy in providing additional information for surgical decision-making, such as lymph node dissection or nerve-sparing surgery, cannot be overlooked.
Future Directions
Further prospective multicenter studies with larger sample sizes are necessary to confirm the feasibility of avoiding biopsy before RP and to establish predictive models based on PSMA PET/CT and mpMRI. The integration of other biomarkers, such as liquid biopsy or genetic evaluation, could enhance the diagnostic accuracy of this biopsy-free pathway.
Additionally, the role of PSMA PET/CT and mpMRI in detecting lymph node metastasis needs further investigation. The development of standardized protocols for imaging and pathological evaluation will be crucial in ensuring the reproducibility and reliability of future studies.
Conclusion
In conclusion, the combination of PSMA PET/CT and mpMRI offers a promising alternative to biopsy for diagnosing csPCa in selected patients. While the study’s findings support the feasibility of avoiding biopsy before RP, the diagnostic efficacy of current imaging criteria remains insufficient for widespread adoption. Strict patient selection, thorough risk disclosure, and further research are essential to validate this biopsy-free pathway and optimize its clinical application.
doi.org/10.1097/CM9.0000000000003204
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