Metastatic Sites' Location and Impact on Patient Management After the Introduction of Prostate-specific Membrane Antigen Positron Emission Tomography in Newly Diagnosed and Biochemically Recurrent Prostate Cancer: A Critical Review

CONTEXT: The introduction of prostate-specific membrane antigen positron emission tomography (PSMA-PET) had a substantial impact on the management of prostate cancer (PCa) patients with a stage migration phenomenon and consequent treatment changes. OBJECTIVE: To summarise the role of PSMA-PET to define the burden of disease through an accurate location of metastatic site(s) in PCa patients, describing the most common locations at PSMA-PET in the primary staging and recurrence setting, and to assess the clinical impact in the decision-making process. EVIDENCE ACQUISITION: A comprehensive nonsystematic literature review was performed in April 2022. Literature search was updated until March 2022. The most relevant studies have been summarised, giving priority to registered clinical trials and multicentre collaborations. EVIDENCE SYNTHESIS: PSMA-PET showed higher diagnostic accuracy than conventional imaging both in newly diagnosed PCa and in recurrent disease. This greater accuracy led to a migration of a higher proportion of patients identified with metastatic disease. Bone metastases were reported as the most frequent site of metastatic spread in staging (up to 17%) and restaging (up to 18%). In staging, considering the suboptimal sensitivity in lymph node metastasis detection prior to radical surgery, PSMA-PET should be performed in patients with high risk or unfavourable intermediate risk only, and it is not recommended to routinely avoid pelvic lymph node dissection in case of a negative scan. In case of prostate-specific antigen relapse, PSMA-PET had higher diagnostic accuracy than other diagnostic procedures in the early detection of the sites of recurrence, thus influencing the therapy decision-making process. CONCLUSIONS: PSMA-PET detects a higher number of lesions than conventional imaging or other PET radiotracers, especially metastatic lesions unseen with other modalities. The high diagnostic accuracy of PSMA-PET leads to a significant patient upstage and thus an impact in clinical management, even if the overall impact on cancer mortality is still to be assessed. PATIENT SUMMARY: Prostate-specific membrane antigen positron emission tomography (PSMA-PET) identifies metastatic lesions with higher accuracy than conventional imaging, both in primary prostate cancer and during disease recurrence. Skeletal metastasis and extrapelvic lymph nodes are the most common sites of metastatic spread. The high accuracy of PSMA-PET in the detection of metastatic disease led to a significant impact on patient management, even if the overall impact on cancer mortality is still to be assessed.