Superscan on 68Ga PSMA PET/CT in patients with metastatic prostate carcinoma: A case series

Abstract

Prostate cancer is the second most common malignancy in men worldwide, with a good prognosis when is detected and treated in early stages, but, when it presents progression to castration-resistant metastatic prostate cancer, most of the cases will have bone metastasis, decreasing the quality of life and life expectancy. For the evaluation of the disease in the routinary clinical practice, 68Ga-PSMA PET/CT, among others is a valuable tool for the evaluation of the disease extension. 68Ga-PSMA PET/CT detects the presence of PSMA receptor in the tumoral tissue, but also has physiologic uptake in certain organs, such as liver, spleen, intestine, kidneys, lacrimal and salivary glands. Total or partial absence of uptake in those organs is rare and may be due to a high metastatic tumor burden, a phenomenon originally described in bone scintigraphy as super scan. We describe a case series of seven patients with prostate cancer from the National Institute of Cancerology in Colombia, in which a super scan pattern was found in the evaluation with 68Ga-PSMA PET/CT, proposing the suppression of uptake in the intestine, liver, spleen, lacrimal and salivary glands as the main criteria for its definition, and showing that renal uptake persists in most cases, considering that, unlike the super scan in conventional bone scintigraphy, this is not a criterion necessary for its definition in the study with 68Ga-PSMA.