Diagnosis of renal cell carcinoma in patients with prostate cancer: capabilities of PET/CT with 18F-PSMA-1007

Background. Prostate cancer (PCa) ranks 4th and 8th in the structure of morbidity and mortality worldwide. Combined positron emission and X-ray computed tomography (PET/CT) with a ligand of a prostate-specific membrane antigen is very encouraging in prostate cancer, renal cell carcinoma (RCC), lung cancer, and breast cancer in the staging work-up of the primary tumor, evaluation of the therapy effectiveness, and observation. Aim. To evaluate the capabilities of PET/CT with 18F-PSMA-1007 for the diagnosis of primary renal tumors in patients with PCa. Materials and methods. The study included 492 patients with histologically confirmed stage I–IV PCa. All patients were examined with PET/CT with 18F-PSMA-1007 during staging work-up, therapy, follow-up, and restaging in case of progression. The imaging was performed on a GE Discovery PET/CT 710 scanner. Results. Twenty-four (4.9%) patients had multiple primary malignancies of various localizations. In 8 (1.6%) of them, clear-cell RCC was diagnosed. The median age was 73.3 years. In most cases, the tumor was synchronous (6 [75%] patients) and metachronous (2 [25%] patients). The tumor was localized in the left kidney in 6 (62.5%) patients and the right kidney in 3 (37.5%) patients. The tumor was diagnosed in the upper segment in 5 cases, in the anterior segment, in 2 patients, and 1 patient had the tumor in the lower segment. The size of the primary tumor averaged 33.8 mm, corresponding to the T1a category. The median SUVmax in the tumor was 17.92. Histological examination of tumor biopsy specimens showed clear-cell RCC. In the first stage, surgical treatment was performed on 7 patients: 2 had laparoscopic nephrectomy, and 5 had organ-sparing interventions with an endoscopic approach. Systemic therapy was administered to 1 patient. Conclusion. PET/CT with 18F-PSMA-1007 is an alternative method for assessing the extension of the tumor process in patients with PCa during therapy and diagnosis. It detected primary multiple renal tumors in 1.6% of patients. The tumor size averaged 33.8 mm, corresponding to the T1a stage. In such cases, treatment should begin with surgery, allowing for the tailoring of treatment options.