As abdominal scans are now very common, early kidney cancer is usually detected incidentally when a scan is performed to investigate another abdominal complaint. The mainstay of treatment is still surgery although it is dependent on the size and characteristics of the tumour. Treatment varies from close observation only to chemotherapy for advanced disease.
A common referral to a urologist is an abnormal kidney scan. This is usually detected because of scanning of the abdomen for another reason, such as abdominal pain. Kidney cysts and concerns regarding kidney cancer are the most common abnormality, but a dilated kidney including pelvi-ureteric junction (PUJ) obstruction is also discussed. Kidney stones are covered in another section.
Generally, an ultrasound or CT of the abdomen is the reason that the kidney abnormality is detected. A GP or urologist may request focussed scans to look at the kidney specifically. Occasionally if even further information is required, an MRI or nuclear medicine scan can be helpful.
Simple kidney cysts are so common that the majority of the population over 50 have them. Generally, they are of no clinical consequence, but can be a cause of concern as they are commonly reported. Sometimes, the cysts may not look regular and the obvious concern is whether there is an underlying kidney cancer. These are generally rare however, and slightly complicated cysts are generally monitored only.
A large simple cyst arising from the lower pole of the left kidney in a patient with medical renal disease. There is also an incidental cyst in the left adnexa.
A solid lesion in the kidney is usually a kidney cancer, although 30% of small tumours may be benign. Thankfully, most kidney cancers detected incidentally are small and are unlikely to have spread. Treatment depends on the configuration of the tumour and health of the patient.
Active surveillance involves watching a small tumour closely. Tumours smaller than 3-4cm usually behave in a benign fashion with a low risk of spreading and display a period of growth before they spread. Therefore, watching the tumour with regular imaging is a valid approach for small tumours, particularly in elderly patients with other medical problems. If the tumour grows over time, surgery may then be discussed.
Radical nephrectomy is an operation where the entire kidney is removed. This is the most straightforward option for treating a kidney cancer and may be performed by “keyhole” (laparoscopic) or open surgery.
Partial nephrectomy is an operation where only the tumour is removed in an attempt to save the remaining kidney. This is a potentially difficult operation with a higher complication rate than a radical nephrectomy as it involves cutting into the kidney which has a large blood supply. Only certain configurations of tumours are amenable to this operation, although there is a theoretical advantage of preserved kidney function
There has been a number of new chemotherapy agents which have become available over the last few years to treat kidney cancer. This is usually reserved for cases where the cancer has spread, but a clinical trial may be offered in specific types of kidney cancer.
In difficult cases where there is no obvious preferred or desirable treatment option, a novel therapy such as ablative techniques or radiotherapy may be discussed.
A “dilated” kidney may be detected on kidney imaging because the urine part of the kidney on one side is much larger than the other. There may be concern that the dilation is due to a blockage where the urine collecting system (renal pelvis) joins the ureter.
Usually this causes intermittent pain on one side of the lower back, similar to a blockage from a kidney stone, particularly with drinking fluid.
The diagnosis may not necessarily be straightforward but if this is the concern, an operation to remove the blocked segment and then rejoin the two ends together (pyeloplasty) over a stent corrects the problem.