In contemporary oncologic diagnostics, molecular imaging modalities are pivotal for precise local and metastatic staging. Recent studies identified fibroblast activation protein as a promising target for molecular imaging across various malignancies. Therefore, we aimed to systematically evaluate the current literature on the utility of fibroblast activation protein inhibitor (FAPI) PET/CT for staging patients with genitourinary malignancies. Methods: A systematic Embase and Medline search was conducted, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) process, on August 1, 2023. Relevant publications reporting on the diagnostic value of FAPI PET/CT in genitourinary malignancies were identified and included. Studies were critically reviewed using a modified version of a tool for quality appraisal of case reports. Study results were summarized using a narrative approach. Results: We included 22 retrospective studies with a cumulative total of 69 patients, focusing on prostate cancer, urothelial carcinoma of the bladder and of the upper urinary tract, renal cell carcinoma, and testicular cancer. FAPI PET/CT was able to visualize both local and metastatic disease, including challenging cases such as prostate-specific membrane antigen (PSMA)–negative prostate cancer. Compared with radiolabeled ¹⁸F-FDG and PSMA PET/CT, FAPI PET/CT showed heterogeneous performance. In selected cases, FAPI PET/CT demonstrated superior tumor visualization (i.e., better tumor-to-background ratios and visualization of small tumors or metastatic deposits visible in no other way) over ¹⁸F-FDG PET/CT in detecting local or metastatic disease, whereas comparisons with PSMA PET/CT showed both superior and inferior performances. Challenges in FAPI PET/CT arise from physiologic urinary excretion of most FAPI radiotracers, hindering primary-lesion visualization in the bladder and upper urinary tract, despite generally providing high tumor-to-background ratios. Conclusion: The current findings suggest that FAPI PET/CT may hold promise as a future tool to aid clinicians in detecting genitourinary malignancies. Given the substantial heterogeneity among the included studies and the limited number of patients, caution in interpreting these findings is warranted. Subsequent prospective and comparative investigations are anticipated to delve more deeply into this innovative imaging modality and elucidate its role in clinical practice.

在当代肿瘤诊断中，分子成像模式对于精确的局部和转移分期至关重要。最近的研究发现成纤维细胞激活蛋白是各种恶性肿瘤分子成像的有希望的靶标。因此，我们的目的是系统地评估目前关于成纤维细胞活化蛋白抑制剂（FAPI）PET/CT 对泌尿生殖系统恶性肿瘤患者分期的实用性的文献。方法：根据系统评价和荟萃分析的首选报告项目 (PRISMA) 流程，于 2023 年 8 月 1 日进行了系统性 Embase 和 Medline 检索。相关出版物报告了 FAPI PET/CT 在泌尿生殖系统恶性肿瘤中的诊断价值被识别并包含在内。使用病例报告质量评估工具的修改版本对研究进行了严格审查。使用叙述方法总结研究结果。结果：我们纳入了 22 项回顾性研究，累计纳入 69 名患者，重点关注前列腺癌、膀胱尿路上皮癌和上尿路癌、肾细胞癌和睾丸癌。 FAPI PET/CT 能够显示局部和转移性疾病，包括具有挑战性的病例，例如前列腺特异性膜抗原 (PSMA) 阴性前列腺癌。与放射性标记的 ¹⁸ F-FDG和PSMA PET/CT相比，FAPI PET/CT表现出异质性性能。在选定的病例中，FAPI PET/CT 表现出优于 ¹⁸ F-FDG PET/CT 的肿瘤可视化效果（即，更好的肿瘤与背景比以及小肿瘤或转移性沉积物的可视化，而其他方式无法看到）在检测局部或转移性疾病方面，与 PSMA PET/CT 的比较显示出优劣的性能。 FAPI PET/CT 的挑战源于大多数 FAPI 放射性示踪剂的生理尿排泄，尽管通常提供较高的肿瘤与背景比，但阻碍了膀胱和上尿路原发灶的可视化。结论：目前的研究结果表明，FAPI PET/CT 有望成为未来帮助临床医生检测泌尿生殖系统恶性肿瘤的工具。鉴于纳入的研究之间存在显着的异质性且患者数量有限，因此在解释这些发现时需要谨慎。预计后续的前瞻性和比较研究将更深入地研究这种创新的成像方式并阐明其在临床实践中的作用。