The kidneys are located on each side of our bodies at the rear of the abdominal cavity and serve the body as a natural filter.
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 3% of adult cancers. The ratio of men to women is 2:1 and 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.
A small part of 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.
Currently, ¾ of kidney cancers are reported to be incidentally diagnosed.
Increase in this rate depends on common use of ultrasonography in “check up” programs. Therefore, the rate of patients receiving early diagnosis is also increases. A solid mass in the kidney in abdominal ultrasonography is suggestive of renal parenchymal tumor. The final diagnosis of patients with pre-diagnose must be established by computed tomography (CT) or magnetic resonance (MRI), which are advanced imaging technologies.
Kidney cancers mostly spread to the lungs and infrequently to the liver, bones, suprarenal gland, cerebral and lymph nodes. The risk of metastasis increases as the diameter of the tumor increases. Studies such as chest radiography, bone scintigraphy, positron emission tomography need to be performed if the physician considers necessary.
Primary treatment of renal parenchymal tumors is to surgically remove the tumor. The most common treatment method is to completely remove the kidney together with surrounding lipid tissue, and suprarenal gland (radical nephrectomy), as may be necessary, depending on the size on localization of the tumor. These surgeries have been performed by conventional surgical methods for years but now are possible to perform with standard laparoscopic or robotic laparoscopic methods.
With this method, the scar on the patient is smaller than that of open surgery; less blood is lost, and the patients can get back to their daily activities earlier. If diameter of the tumor is 4 cm or smaller, only tumor needs to be removed (partial nephrectomy –nephron-sparing surgery). Removal of tumor by conserving normal renal tissue can be either performed by conventional open surgery or by standard laparoscopic or robotic laparoscopic methods. Conventional open radical nephrectomy should be performed when the tumor is very large, or tumor thrombus is present in the renal vein.
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. Cancers of collecting system, known as renal pelvis and urethral tumor, are histologically similar to bladder cancers. Smoking and being exposed to certain chemical substances are known to increase the risk of development cancer of collecting system.
Most patients spot the hematuria (blood in the urine). This bleeding may sometimes occur with clots. The rare symptoms include the side pain, nausea, and vomiting. It is very difficult to diagnose this tumor. Computed tomography (CT) or magnetic resonance imaging (MRI) will help diagnosis of patients 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. It is possible to treat the tumor with this method when the tumor is small.
The ideal treatment for cancers of renal collecting systems is to surgically remove the kidney together with urethral canal including the normal tissue where urethral canal enters the bladder. 2 different incisions were made to remove the kidney and lower urethral canal by conventional open surgical method. Currently, an incision in 7 cm is made on the patient to remove only the kidney and other tissues in this surgery that can also be performed laparoscopic. Clinical studies suggest that laparoscopy technique can safely be used in such cancer types. Our team has successfully operated 25 patients using this method and achieved positive outcomes.
The bladder of the patients who have undergone a surgery for the tumor of renal collecting system, i.e. renal pelvis and urethral tumor should be checked during the surgery and periodically after the surgery because of the risk of development of a tumor.