Imaging is important for the diagnosis and classification of kidney tumours. Most common imaging techniques are ultrasound, CT scans, and MRI. In some cases a biopsy is done to get more insight into the specific characteristics of the tumour.
After a tumour is detected, the doctor first needs to know whether it is malignant. A contrast-enhanced ultrasound, CT, or MRI scan of the abdomen and pelvis provides information about this. CT and MRI scans also show:
- The location and size of the tumour
- Whether or not you have enlarged lymph nodes
- Whether or not the tumour has spread to neighbouring organs, such as the adrenal gland, liver, spleen or pancreas
- Whether the urinary tract is affected by the tumour
For a contrast-enhanced scan, a contrast medium is administered through an IV, usually in your arm. The contrast medium highlights your veins and arteries by giving them a different colour in the pictures taken during the scan. This type of scan allows the radiologist to analyse the tumour. The results will guide the treatment you receive.
If you are allergic to contrast medium, you will receive an MRI or CT scan without contrast enhancement.
If your doctor thinks the cancer may have spread to the lungs, you will get further tests, like a CT scan. You may need a bone or brain scan if you have symptoms such as bone pain or epileptic seizures. These scans are done to see whether the cancer has spread to bones or the brain.
Renal tumour biopsy
During a renal tumour biopsy, one or more samples of tumour tissue are taken. First you receive local anaesthesia. Then the doctor inserts a needle through your skin and uses ultrasound or CT imaging to locate the tumour. The tissue samples are analysed by the pathologist in order to help determine future treatment.
Renal biopsy is not standard procedure in the diagnosis of kidney cancer. You may need a biopsy in case:
- The results of your scan are not clear enough
- You have a small tumour which could be treated with active surveillance
- You have a small tumour which could be treated with radiofrequency ablation or cryotherapy
Biopsies may cause blood in the urine. In rare cases they can cause more severe bleeding. A renal tumour biopsy is generally a harmless procedure.