Staging of kidney cancer is primarily achieved by computerized tomography (CT) scans or magnetic resonance imaging (MRI). If a patient is found to have limited metastatic disease, surgical removal or radiation therapy could be considered in order to control the majority of the disease. However, if metastases are more widespread, systemic (drug) therapy may be the preferred management option. The identification of additional metastatic sites using more sensitive imaging modalities therefore has the potential to alter management, and this remains an unmet need in the field. This study will investigate the utility of positron emission tomography (PET) imaging with PSMA (prostate specific membrane antigen). Kidney cancer of the clear cell subtype has demonstrated high expression of PSMA, making it a disease in which PSMA-targeted PET imaging could help to identify occult metastatic disease.

This will be a single-institution prospective, open-label feasibility study involving patients ≥18 years of age with metastatic clear cell RCC who have not yet received systemic therapy. Patients with evidence of metastatic disease on conventional imaging will require histologic confirmation by biopsy. At our institution, approximately 26 new metastatic clear cell RCC (mRCC) patients are seen each year, and a previous analysis reported that 92% of 10,105 patients with mRCC in the International mRCC Database Consortium (IMDC) database were found to have clear cell histology; therefore, difficulty with recruitment into this study over a period of 2 years is not anticipated.

Inclusion Criteria:

1. Men and women with histologically-proven, metastatic renal cell carcinoma (RCC)(TNM stage Tany, Nany, M1)
2. Must have baseline conventional imaging of the chest, abdomen, and pelvis with contrast-enhanced CT or MRI within 5 weeks of enrolment. Contrast is required unless the participant cannot for medical reasons (ie renal failure).

Exception: Unenhanced CT of the chest is acceptable Exception: Unenhanced MRI of abdomen and pelvis is acceptable in cases of renal failure

Exclusion Criteria:

1. Pregnant or breastfeeding
2. Age less than 18
3. Histology does not have any clear cell component
4. Unable to lie flat for 30 minutes for the scan
5. History of prior malignancy (except non-melanoma skin cancer)
6. Unable to provide informed consent
7. Inadequate liver function
8. Systemic or radiation-based cancer treatment is needed urgently and anticipated to begin before PSMA scan can take place
9. Previously exposed to systemic or radiation cancer therapy (except radiation for skin cancer)