Kidney cancers can be grouped in two; parenchymal tumors develop in where kidney produces the urine and cancers originate from where urine is collected (collecting system). We first describe parenchymal tumors and then cancers of collecting system.
Renal parenchymal tumors account for about 3% of adult cancers. The ratio of men to women is 2:1. It often occurs at the age of 50-60. It is known that the incidence of kidney cancer is higher in those with congenital renal disease (e.g. horseshoe shaped kidney, polycystic kidney disease) and systemic diseases (e.g. von Hippel-Lindau syndrome). It is reported that it is more common in patients with chronic kidney disease. Smoking has been proven to increase development of kidney cancer. In addition, excessive use of analgesics is reported to increase the risk of development of renal parenchymal tumor.
In diagnosis of renal parenchymal tumor, the symptoms include haematuria (visible blood in the urine), side pain and palpable mass, which are known as classical trinity and present in 10-15% of the patients. Many cases are incidentally identified during an imaging for various reasons. Approximately 1/3 of the cases are metastatic at the time they are diagnosed. The patients admit to the hospital with metastasis-related complaints (e.g. cough and shortness of breath in lung metastasis and bone pain and fractures in bone metastasis), and can be diagnosed in this way. The rate of incidental diagnoses of kidney cancers is gradually increased with common use of imaging methods.
In addition, a number of syndromes may help diagnosis, such as paraneoplastic syndrome that is not directly related to the tumor but occurs in the presence of tumor. Paraneoplastic syndromes that often occur in renal parenchymal tumors are increased red blood cell count, hypertension, hypercalcemia, and liver dysfunction not related to metastasis.
As expressed before, diagnosis of renal parenchymal tumors are often incidental. After detecting the mass in a routine check-up ultrasonography, a further imaging method (especially computed tomography, and sometimes magnetic resonance imaging) will allow a detailed evaluation, and extensity of the disease; a treatment plan then can be made.
Primary treatment of renal parenchymal tumors is to surgically remove the tumor. In radical nephrectomy the complete kidney is removed together with surrounding lipid tissue depending on the size on localization of the tumor. In partial nephrectomy – nephron-sparing surgery, the surgeon removes the cancer and part of the kidney surrounding it but some of the kidney is left behind so there will be some working kidney left after the operation. Oor team successfully performs both radical nephrectomy and partial nephrectomy using laparoscopic methods and robot-assisted method. Open surgery is required for some particular cases (e.g. open radical nephrectomy in the presence of large tumor, or open partial nephrectomy depending on localization and/or size of the tumor). The role of chemotherapy and radiotherapy is very limited in renal parenchymal tumors. New agents are being developed and offered to clinical use for this tumor, which is highly resistant to chemotherapy. Radiotherapy is only useful in treatment of metastatic lesions (e.g. bone and brain).
Cancer of renal collecting system is rare. It usually occurs at old ages. The ratio of men to women is 1 to 2-4. Smoking and being exposed to certain chemical substances are known to increase the risk of development cancer of collecting system.
Of the cases, 70-90% has hematuria (blood in the urine) and 8-50% may experience side pain. Some cases present with metastasis-related symptoms (loss of weight and appetite). A computed tomography or magnetic resonance imaging will allow making diagnosis in cases with suspected cancer of renal collecting system. However, the kidney may be accessed through urethra by a flexible urethroscope to collect biopsy from the kidney in order to establish the diagnosis.
Information on kidney functions is essential when making a treatment plan. The treatment of a patient who has two functional kidneys is to remove the kidney with cancer and urethra (nephrouretereetomy). This operation is performed by our group hospitals using laparoscopic standard methods or a robot. Open surgery is rarely required for some cases.
Endoscopic treatment is the treatment of choice in patients with one kidney, in the presence of disease in both kidneys, or in patients with renal dysfunction in which case the kidney should be conserved.
Treatment may vary depending on the patient condition, and chemotherapy and/or radiotherapy can be used.