General and more comprehensive text about cancer diseases, their behavior, causes and treatment can be found here.
Kidney cancer (renal cell carcinoma) is a dangerous malignant tumor growing from the kidney tubules. These tubules are small channels allowing the flow of filtrated urine. The kidney cancer is also historically known as the Grawitz tumor.
The causes of this cancer are unclear. There is a probable influence of genetics as the tumor may have a familial occurrence. In addition, it is assumed that smoking, obesity and chronic untreated hypertension damaging the kidneys also increase the risk of tumor.
Kidney cancer must be regarded as extremely dangerous. The first reason is that the tumor has initially no symptoms and it is often diagnosed when it is too late. Sometimes, blood in urine can be found and a painless lump in the abdomen may be palpated when there is a large tumor mass. However, the tumor is frequently just an incidental finding during a routine abdominal ultrasound.
Advanced stages may cause abdominal pain due to the growth of the tumor mass and also symptoms of metastatic spread such as the weight loss, night sweats, loss of appetite, slightly elevated temperature and others. Kidney cancer (similarly to melanoma) has quite unpredictable behavior and it may metastasize very early and practically anywhere. The most frequent targets of metastases are lungs, bones and brain. Symptoms are particularly frequent in bone metastases that manifest with bone pain and pathologic fractures.
The early stage can be incidentally found by abdominal ultrasound, thanks to visible blood in urine, or by finding trace amount of blood by urinalysis. Local extent of the tumor, its relationship to adjacent anatomical structures and presence of metastases can be evaluated by computed tomography. Definitive confirmation of the tumor and its histological attributes is possible after histological examination from the tissue obtained by surgery.
Surgical intervention is the main option. The tumor mass must be removed, usually together with the affected kidney (nephrectomy). Kidney cancer in late stage with presence of distant metastases can be treated by chemotherapy or biological treatment*, but the outcome is very poor and the chance of long-term survival low.
* In this context, the term biological treatment means administration of special substances that prevent the tumor from creating its own blood vessels. This disrupts the nutrition of the tumor tissue and blocks its growth.