ORIGINAL ARTICLE PSMA whole-body tumor burden in primary staging and biochemical recurrence of prostate cancer Allan Santos 1,2 & Aline Mattiolli 1 & José BC Carvalheira 3 & Ubirajara Ferreira 4 & Mariana Camacho 1 & Cleide Silva 5 & Fernanda Costa 6 & Wagner Matheus 4 & Mariana Lima 1,2 & Elba Etchebehere 1,2 Received: 7 May 2020 /Accepted: 27 July 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020 Abstract Purpose The objective of this study was to evaluate whether 68 Ga-PSMA PET/CT whole-body tumor burden (PSMAwbtb) is associated with clinical parameters and laboratory parameters in prostate cancer patients. Methods We retrospectively evaluated prostate cancer patients submitted to PSMA PET/CT for primary staging purposes or due to biochemical recurrence (BR). PSMAwbtb metrics (total volume of PSMA-avid tumor (PSMA-TV)) and total uptake of PSMA- avid lesions (PSMA-TL) were calculated semi-automatically. Spearman’s rank correlations between PSMAwbtb metrics and clinical, laboratory parameters (age, time-to-BR, years of diagnosis of prostate cancer, free and total serum PSA levels, and the Gleason score) and with the highest SUVmax of a lesion (hSUVmax) were analyzed. Results Among the 257 PSMA PET/CT studies, there were 46 scans (17.9%) performed for primary staging and 211 (82.1%) for BR. PSMA-TV and PSMA-TL were calculated for the 157 positive scans (58.8%), which were 43 patients (93.5%) in the primary staging group and 114 patients (54.0%) in the BR group. In the primary staging group, we observed a significant correlation between PSMA-TL and hSUVmax (p = 0.0021). In the BR group, there was a significant direct correlation between PSMA-TL and the variables age (p = 0.0031), total serum PSA values (p = < 0.0001), free serum PSA values (p = < 0.0001), and the hSUVmax (p = < 0.0001). Similar results were obtained for PSMA-TV. Conclusion PSMAwbtb has a direct and positive correlation with serum PSA values and age in prostate cancer patients with BR. Keywords 68 Ga-PSMA . PET/CT . Prostate cancer . Tumor burden Introduction Prostate cancer is the second most frequent malignant neo- plasm in men, being the sixth cause of death according to the World Health Organization [1]. Advances in diagnostic imaging, surgeries, radiotherapies, secondary hormonal ther- apies, and chemotherapies have increased both diagnostic and therapeutic efficacy, facilitating the management of patients with prostate cancer and improving quality of life [2–4]. In spite of this, more than 50% of high-risk prostate cancer pa- tients develop biochemical recurrence (BR), after initial ther- apy [5]. Imaging plays an essential role in the evaluation of inter- mediate and high-risk prostate cancer patients and gallium- labeled prostate membrane-specific antigen ( 68 Ga-PSMA) performed on positron emission computed tomography com- bined with computed tomography (PET/CT) scanners has gained widespread use as it essentially translates tumor mo- lecular biology into clinical reality. 68 Ga-PSMA PET/CT is This article is part of the Topical Collection on Oncology - Genitourinary * Elba Etchebehere elba@hc.unicamp.br 1 Medicina Nuclear de Campinas, Campinas, São Paulo, Brazil 2 Division of Nuclear Medicine of the Department of Radiology, Campinas State University (UNICAMP), Rua Vital Brazil 251, Campinas 13083-888, Brazil 3 Division of Oncology of the Department of Internal Medicine, Campinas State University (UNICAMP), Campinas, Brazil 4 Division of Urology of the Department of Surgery, Campinas State University (UNICAMP), Campinas, Brazil 5 Department of Biostatistics, Campinas State University (UNICAMP), Campinas, Brazil 6 Hospital Procardíaco, Rio de Janeiro, Brazil European Journal of Nuclear Medicine and Molecular Imaging https://doi.org/10.1007/s00259-020-04981-x