Renal cell cancer often affects elderly people. Even though its development has not been fully understood yet, what is known is that interdisciplinary treatment is indispensable for the optimal care of patients suffering from this disease.
The human body has a pair of kidneys located behind the peritoneum. The blood to be filtered – a total of 1,200 ml every minute – is transported to the kidneys via the renal artery. A person's entire blood volume is cleaned approximately once every 5 minutes. Blood is filtered in a small vascular nodules, the so-called glomeruli. When blood is purified, metabolic waste products and, possibly, medication are excreted. At the same time, the fluid balance, salt balance and acid-base balance of our body are also regulated. Among other things, this takes place in the duct system (tubule system) of the kidney, which connects the tuft of vessels with the renal pelvis. The urine is finally collected in the renal pelvis and transported via the ureter to the bladder. In addition, the kidneys also participate in vitamin D metabolism and produce a hormone that stimulates blood production. Kidney function is therefore essential to life.
Every year, a total of 16,000 people are diagnosed with renal cell cancer in Germany, currently with a slightly increasing trend. Men are affected twice as often as women. The average age of men suffering from renal cell cancer is 68 while that of women is 71. Thus, renal cell cancer is the 6th most common type of cancer in men and the 10th most common type of cancer in women among the German population.
The most common malignant tumour in the kidney is the so-called clear cell renal cell carcinoma (RCC). Clear cell renal cell carcinoma often develops from the initial duct system (proximal tubule). However, there are more than 50 different known malignant tumours of the kidney. The underlying mechanism due to which cells in the body start growing uncontrollably, infiltrating adjacent tissues and forming metastases is not yet fully understood.
In renal cell cancer, there are congenital genetic risk factors that are unalterable. If a person’s first or second degree relative suffers from renal cell cancer, then the probability of that person developing it in the course of life is 2 to 4 times higher. In rare cases, the development of renal cell cancer can be attributed to changes in a single gene, for example, the von Hippel-Lindau syndrome. In addition to genetic risk factors, there are also acquired risk factors. These include smoking, high blood pressure and obesity. The loss of kidney function in the final stage (terminal renal insufficiency) is also a risk factor for the development of renal cell cancer.
Every second case of renal cell cancer is discovered by chance during an imaging examination. If renal cell cancer is suspected, the kidneys can easily be assessed by ultrasound. An experienced doctor can distinguish between a renal cell carcinoma and a simple kidney cyst in more than 90 percent of cases. A computer tomography (CT) is then performed for a more precise assessment of the spread of the malignant tumour. Under certain circumstances, it may be necessary to remove tissue from the renal cell carcinoma using a hollow needle (biopsy) in order to plan further therapy. In addition, an X-ray examination of the thorax is performed to look for metastases in the lungs. Skeletal scintigraphy is recommended if there is a suspicion of metastasis in the bones.
In the initial stages, renal cell cancer is often asymptomatic or shows very few symptoms. Some patients complain of non-specific symptoms such as persistent fatigue, unintentional weight loss or night sweats. As the disease progresses, there may be blood in the urine and flank pains may occur. In the advanced stage of the disease, renal cell cancer can cause metastases in the lungs, bones, liver and brain. In the event of a metastasis in the skeleton bone pain may occur.
At the time of initial diagnosis, in most patients, renal cell cancer is at a stage where the carcinoma is restricted locally to the kidney. The current gold standard for renal cell cancer is always the complete surgical removal of the tumour depending on the stage, including the entire kidney and surrounding structures, if any. Surgery is the first choice even when renal cell cancer has already formed metastases, which can be surgically removed in conjunction with other specialist disciplines. No further medication is necessary after a complete surgical removal. Regular follow-up appointments are necessary due to the possibility of recurrence (relapse) of renal cell cancer.
Drug therapy becomes necessary when it is no longer possible to completely remove the renal cell carcinoma due to local spread or metastasis. However, surgical removal of the affected kidney can still be considered in patients with good general health.
It has been seen that the removal of the main tumour slows down the progression of metastases. Conventional chemotherapeutics and radiation have little effect on renal cell cancer. Therefore, targeted therapies are necessary in the advanced and metastatic stages of the disease.
Like the entire kidney, renal cell carcinoma is often very well supplied with blood. Continuous and high blood supply helps the renal cell carcinoma grow. Targeted therapies inhibit vascularisation in renal cell carcinoma. The malignant tumour is no longer sufficiently supplied with blood, and consequently the tumour “starves” – the progression of the disease is slowed down. A further starting point is the activation of the patient's own immune system by so-called “checkpoint inhibitors” to combat renal cell cancer.
Currently, special preventive check-ups for the early detection of renal cell carcinoma are not recommended for the general population in Germany.