Due to "early stopping rule" as defined in the study protocol

The main objective is to study whether imaging detection of the biomarker DAT can be used to detect kidney tumors identified by computer tomography (CT), which are pathologically assesses as being of the clear cell subtype.

Main objective of the trial:

The main objective is to investigate whether DaTSCAN with subsequent SPECT can detect elevated DAT levels in at least a lesion identified with CT in patients with clear cell renal cell carcinoma, as assesed by pathologist? DaTSCAN signal will be seen as positive, displaying intensity ≥3ggr higher than the background and correlating anatomically with at least one lesion found with CT. DaTSCAN is used routinely to detect the loss of dopaminergic neurons in the striatum of patients with clinically uncertain Parkinsonian Syndromes. The active substance in DaTSCAN, Ioflupane specifically binds to DAT. By analyzing the focal uptake of Ioflupane (123I) with SPECT / CT the progression of the disease may be clarified. In light of our findings that clear cell renal cancer express significantly elevated levels of DAT, we postulate that DaTSCAN can be used for detection of clear cell renal cell carcinoma.

Protection of trial subjects:

Very few adverse effects are reported for DatSCAN use. In this study we used the same dose and route of administration as is praxis for DaTSCAN when used for diagnostic investigation of Parkinsons disease. Albeit uncommon, pain at the injection site has been previously reported when the solution was injected into a small vain. To minimise the potential for pain at the injection site during administration in this study, a slow intravenous injection (not less than 15 to 20 seconds) via an arm vein was therefore applied. The injections were performed by routined staff at Skåne University Hospital, Department of Clinical Physiology / Nuclear Medicine in Malmö, where usual clinical preparedness for allergic reactions after injection was available.

Background therapy:

Patients underwent appropriate thyroid blocking treatment prior to injection of DaTSCAN, to minimise thyroid uptake of radioactive iodine. In this study, this was achieved by oral administration of 2x 65 mg potassium iodide tablettes on the night before the DaTSCAN investigation and another 2x 65 mg potassium iodine tabletts 1 hour prior to injection of DaTSCAN.

Inclusion Criteria:

• suspected kidney cancer diagnosis
• suspected spread of the cancer
• patient is scheduled for surgery alternatively biopsy of kidney tumor
• patient is 18 years or older
• the patient has given their consent to participate in the study
• female patients of reproductive age displays negative pregnancy test

Exclusion Criteria:

• known or suspected allergy to Ioflupane or sodium acetate or acetic acid or ethanol
• patient suffers from moderate to severe renal impairment and exhibits glomerular filtration rate (GFR) <40
• patient is medicated for Parkinson's disease
• patient is medicated with any of the following medications: amphetamine, benzatropine, buproprion, cocaine, mazindol, methylphenidate, phentermine, sertraline, levodopa, dexamphetamine, lisdexamphetamine, modafinil, moclobemid, venlafaxine
• patient is pregnant
• breastfeeding
• patient suffers from mental inability unwillingness or language difficulties resulting in difficulty in understanding the meaning of taking part in the study

AE were reported consecutively for each patient while included in the trial, from potassium iodide intake to two days after Datscan examination, 4 days in total.

AE were reported consecutively for each patient while included in the trial. Incidents may be observed by a doctor / nurse or reported by the subjects themselves. The subjects were asked an open question "Have you had any health problems since taking potassium iodide?" at each relevant study visit (below).

• When injecting DaTSCAN (Ioflupan I123)
• Immediately after the SPECT investigation
• 2 days after the DaTSCAN examination (through telephone interview from research nurse)

Only 5 out of 10 intended patients were recruited in the study due to "early stopping rule" as defined in the study protocol as: terminate study if 4 patients with, by pathologist verified, ccRCC all display negative ioflupane signal in all lesions.