- What Are The Functions Of The Kidney?
- What is a Kidney Cancer?
- What Are The Causes Of The Kidney Cancer?
- What Are The Symptoms For Kidney Cancer?
- Diagnosis of kidney cancer
- Early Diagnosis of Kidney Cancers
- What is a renal cyst?
- Tumor Size in Kidney Cancers
- Kidney Cancer Operation
- Postoperative phases of kidney cancer operations
- Radical nephrectomy operation
- The video showing the kidney cancer operation
The functions of the kidney, characteristics of kidney cancer, causes of kidney cancer, its symptoms and diagnosis methods will be described here. Surgery will be stressed as the sole treatment method. In many cancer types, drug treatment (chemotherapy) and radiotherapy (radiation therapy) can be employed in addition to the surgical treatment. But in kidney cancer, surgical treatment is the ultimate mode of therapy.
What Are The Functions Of The Kidney?
The kidneys are two bean-shaped organs with a size of a fist, located in the lumbar region in the abdominal cavity. It is primary duty of the kidneys is to filter the blood and turn the waste matter in the blood into urine. Each kidney has approximately 1 million nephrons which are microscopic kidney units which filter out the waste products in the blood.
What is a Kidney Cancer?
Kidney cancer or renal cancer is the formation of a tumor by the kidney cells through uncontrolled proliferation. Certain cancers and tumors are not malignant as they do not characteristically spread to remote tissues or organs. When cancerous cells grow and spread to other organs through blood veins (metastasis), they create a mass. The cancers are classified in two groups based on the size of the mass (stage) and the aggressiveness of the cell (grade).
There are many types of kidney cancer. Some cancer types are not aggressive while others are very aggressive with the development of metastasis. The type of the cancer can be verified only following the surgical removal and pathological examination of the mass. In this regard, the kidney cancer differs from other cancers.
What Are The Causes Of The Kidney Cancer?
Male gender and tobacco consumption are the two factors that increase the kidney cancer risk twice. It was demonstrated that the risk of kidney cancer occurrence increases in connection with obesity and extended use of certain analgesics and with the long-time chronic dialysis patients (four times).
The people who have a history of kidney cancer in their families are faced with the risk of kidney cancer. The Von Hipel-Lindau syndrome is a hereditary disease characterized with multiple tumor formation in both kidneys and that can developed in many individuals in the same family.
What Are The Symptoms For Kidney Cancer?
Kidney cancers tender to develop silently without many symptoms until late stages. In the past, it would be diagnosed with a palpable mass, hemorrhage and weight loss. Today, 70 percent of kidney cancers are diagnosed coincidentally and without any symptom at an early stage using imaging methods. Thanks to early diagnosis, patients can be saved from cancer with certainty for the rest of their lives.
Diagnosis of kidney cancer
Retention of the contrast material administered intravenously helps to determine the size and location of the tumor (contrast MR and CT). However, no imaging method can tell you whether the detected mass is benign or malign. For this reason, all masses detected inside a kidney should be removed to get a definitive diagnosis through pathological examination.
Most kidney cancers are detected coincidentally in ultrasonography and computed tomography (CT). MR and CT images can sufficiently show the local spread and remote metastasis of the tumor. MR is better than CT in showing the spread of the cancer inside the vena cava.
MR angiography, on the other hand, is very good in demonstrating the anatomy of the intrarenal vascular structure. Some kidney tumors grow completely centrally (inside the kidney). Their surgical removal is more complicated. In these patients, the surgical success increases as the MR angiography gives the location of the tumor.
Before the operation, chest X-ray should be taken for every patient. Lugs are the most frequent metastasis sites for kidney cancers. Positron emission tomography (PET) scans have nothing to do with the diagnosis of kidney cancers.
Biopsy would be carried out on the tumor base during partial nephrectomy (kidney cancer operation) and pathological examination would be conducted. This approach has been abandoned as the studies demonstrated that this operation was unnecessary.
Place of Biopsy in the Diagnosis of Kidney Cancers
Biopsy made in connection with a kidney cancer is not reliable. It may skip the existing cancer (false negative).
Early Diagnosis of Kidney Cancers
Methods such as ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) are used for the diagnosis of many diseases and cancers. Such imaging methods required for different diseases can provide images of all intra-abdominal organs. These methods also make it possible to diagnose kidney cancers before tumors can grow too much. The rate of the kidney cancers that are diagnosed coincidentally and at an earlier stage is 70%.
Early diagnosis of the cancer enables surgeons to conduct partial nephrectomy, which means the removal of the cancerous section of the kidney without removing it completely. As the studies demonstrate that the patients can live longer if the remaining renal texture is well preserved, partial nephrectomy is becoming increasingly popular. Partial nephrectomy is a complicated operation that requires extensive experience depending on the size and location of the tumor inside the kidney. It is reported that the 25-30% of the masses below 3 cm that are early diagnosed do not tend to spread. (Oncocytoma, angiomyolipoma, hypertrophied columns of Bertin).
What is a renal cyst?
In medical parlance, a mass or tumor is a formation that is filled with solid matter. A cyst, on the other hand, refers to a sac containing fluid. Not every cyst is a cancer. With age, cysts with various sizes may develop inside the kidney. They are harmless and generally require no treatment. According to the uptake of contrast, Bosniak classified cysts into four groups. Groups I and II are benign. Half of Group III (50%) may be cancerous. Group IV are cystic cancers Contrast imaging methods can be used to verify whether cysts are malign or not.
Tumor Size in Kidney Cancers
Smaller tumors are assumed to be less aggressive. It was shown that 30% of the masses smaller than 2 cm and 20% of those that are smaller than 3 cm are benign. Imaging methods and biopsy have limited importance in the definitive diagnosis. Kidney cancers tend to be the most heterogeneous cancers. Even small masses with extremely anarchic cellular structure may develop metastasis, albeit rarely. Every mass detected in the kidneys of healthy people with longer life expectancy should be removed with a surgical operation. Small tumors detected in elderly patients with a poor medical condition who cannot possibly survive a surgical operation should be monitored to determine their grow rates using periodically imaging methods (active follow-up).
Imaging methods cannot fully determine whether the mass is malign or benign. Every mass inside a kidney should be surgically removed.
Kidney Cancer Operation
Kidney cancers can be treated through surgical operations. There are two types of surgical operations for kidney cancers. After the detection of a mass in the kidney, physicians made a decision to proceed with partial nephrectomy or radical nephrectomy taking into consideration the overall health of the patient as well as the condition of the kidney involved. In some cases, they may decide not to conduct any surgical operation.
Radical nephrectomy means the removal of the kidney completely. The other surgical operation is the partial nephrectomy in which the cancerous tissues and those tissues which are several centimeters in the vicinity of the tumor and which are suspected of being cancerous are removed only. The healthy tissues of the kidney are kept in place.
What is partial nephrectomy?
Partial nephrectomy is a complicated operation that requires extensive experience for removing cancerous mass inside the kidney instead of removing the entire kidney. Partial nephrectomy is the preferred method of treatment because the patient will always need the healthy renal tissues that are left behind after the tumor is removed. The removal of the entire kidney through radical nephrectomy would have an adverse effect on the quality of life of the patient who may be required to undergo dialysis in the future.
The cases where partial nephrectomy is indicated:
Simultaneous tumor formation in both kidneys;
Detection of cancer in the kidney of the patients who have a single kidney congenitally or due to the previous removal of one kidney;
When the other and non-cancerous kidney a poorly functions due to kidney stones, pyelonephritis (inflammation of the kidney) or renal arteries; and
The disorders which undermines the functioning of both kidneys such as diabetes and high blood pressure. In these cases, partial nephrectomy is the only course of action.
In some cases, radical nephrectomy may be used even for the patients whose other kidney is healthy. However, we prefer partial nephrectomy in order to leave behind as much healthy tissue as possible. This is also the method advised in the international guidelines.
Why is partial nephrectomy challenging?
Kidneys are characterized with much blood. A kidney has two main veins: the artery which brings in the arterial blood and the vein which takes away the venous blood. The renal artery enters the bean-shaped kidney at its indented section and its distribution inside the kidney is the fingers of a hand. These five small arteries are divided further into branches and they do not anastomose with other arteries (end artery) and the arterial network is terminated inside the organ. In other words, the kidney portions which cannot receive blood will die as they are not fed with other arteries. This will result in infarction. If the renal artery is obstructed completely, the kidney can survive the lack of blood only for 20 minutes. If the kidney is deprived of blood for 30 minutes, it loses all its functions. This vascular distribution inside the kidney creates complications for partial nephrectomy.
Renal hilum is defined as the recessed central section of the kidney where vessels are distributed. The tumors that are formed in this section are risky and complicated as they are located near the distribution hub of the vessels as well as the renal calyces. If tumors grow outwardly (exophytic tumors), their surgical removal is easier. Endophytic (inward growing) tumors, on the other hand, cannot be observed during the operation as they are located at a deeper position. Their surgical removal is more complicated. Likewise, partial nephrectomy of cystic kidney cancers (Bosniak type III-IV) is also complicated as the cystic cancer may disintegrate and spread to the surrounding tissues. It is a sine qua non principle of cancer surgery to remove the cancer in its entirety. If the tumor disintegrates during the removal, this may lead to the spread of the disease to the surrounding tissues. For this reason, the removal of the cystic kidney tumors without disrupting their integrity requires more expertise and skill.
Partial nephrectomy closed surgery
Partial nephrectomy can be performed using the open, laparoscopic and laparoscopically assisted robotic surgical methods. Open surgery for partial nephrectomy is still the gold standard. This is because the surgeon has to remove the tumor in 20 minutes after clamping the renal artery (to temporarily stop the blood flow); otherwise, the kidney suffers from serious damage. It is not likely to finish partial nephrectomy in 20 minutes in laparoscopic or robotic closed surgery. In addition, with the closed surgery, it is not possible to cool down the kidney to in order to make it live up to 1 hour. Closed surgery is especially harder for the complicated kidney cancers. For this reason, open partial nephrectomy is still the most preferred form of surgical operations for kidney cancers around the world.
Experienced surgeons can easily remove all types of simple and complex tumors through open partial nephrectomy. However, closed method allows the removal of only simple tumors even if your surgeon is experienced.
Partial nephrectomy open surgery
The first priority is to get the renal arteries and veins and control both vessels by hanging them separately. The tumor is removed depending on its location and size. After the renal artery is clamped (temporarily stop the blood flow), the kidney can tolerate lack of blood for 20 minutes at most. If it is believed that the surgical removal of complex tumors may exceed this period, ice slush is placed around the kidney after the renal artery is clamped. The kidney is cooled down. In this way, the kidney can tolerate lack of blood for up to 1 hour. This also extends the time to be used for the operation. Clamping the renal artery temporarily paves the way for a blood-free working environment, thereby making the operation smoother.
Partial nephrectomy standard surgery:
The abdominal wall has three layers of strong, transverse muscles in order to protect the intestines and other viscera. In the standard open surgical technique, a 10-12-cm incision is made beneath the ribs and along the side wall of the abdomen. Three layers of abdominal muscles that transverses each other in the abdominal wall are incised. The kidney section is accessed. The renal artery is taken under control and the operation is performed. As these three layers of muscles are cut down and the nerves that ensure the contraction and relaxation of the abdominal muscles in this region may be cut down, muscular contraction disorders may develop postoperatively. However, as this incision is located lower than the kidney, access to the kidney is difficult. We do not use this method.
In the other open surgical technique, an incision parallel to the rib cage is made. Three layers of abdominal wall muscles are cut down. The inside of the peritoneum containing the visceral organs such as the stomach, intestines and the spleen is accessed. If the degree of access to the inside of the peritoneum is smaller in a surgical operation, the postoperative complications will be fewer. The renal artery is accessed and partial nephrectomy is performed. This open surgical technique is much more traumatic for the patient. Due to the incision of three abdominal muscles and entry into the peritoneum, postoperative recuperation lasts longer. We do not prefer this method either.
The surgical technique we employ:
In our technique, incision is made over the tenth or ninth rib depending on the location and size of the tumor. No muscle is cut down as there are no abdominal muscles in this region. In addition, no damage is done to the nerves. More importantly, the incision is located at a higher position so that it allows a top-down and overall view of the kidney and its main vessels. The access to the main vessels of the kidney is easier. The length of the incision is shorter compared to the other techniques. However, it is a more complicated technique as the entry point is above the chest cavity that contains the lungs, and as such, it requires experience. The pleura, the chest cavity membrane that protects the lungs, should be pushed upward. In some cases, it has to be incised due to the location of the tumor. In this case, the operation continues. After the surgery is finished successfully, the pleura is stitched to the diaphragm with its muscle in an air tight manner. There is no need to place a chest tube. In short, this incision allows access to the kidney –which is located at the back of the abdomen– from behind without entering the peritoneum and provides a wider view. Moreover, the peritoneum is not incised unnecessarily and visceral organs are left unharmed.
When the renal artery is clamped temporarily (stop the blood flow), the kidney suffers from damage for lack of blood even for 20 minutes. This is not permanent. The kidney will regain its functionality. In the slides next to the page, we present a patient who suffered simultaneously from the renal tumor and the adrenal tumor. Due to the size of the tumor and its location inside the depths of the kidney, the kidney was clamped (to stop the blood flow) during the operation. Yet, there are advances in the partial nephrectomy technique. Newly developed techniques now allow surgical operations to be conducted without clamping the renal artery (i.e., without stopping the blood flow), depending on the size and location of the tumor. This technique is called zero ischemia technique. In this method, the renal artery is not clamped, and the arteries to the tumor are found and stitched. As other parts of the kidney are not deprived of blood, the healthy renal tissues are saved from trauma and stress. It is a difficult technique to apply.
Using the above-mentioned incision, we clamp the renal artery (to stop the blood floor) and remove the cancerous section. However, if the location and size of the tumor allows it, we leave the kid free and take it under control by hanging the vessels and we don’t clamp the renal artery. We do not lead to renal ischemia. The renal tissue of 2-3 ml all around the tumor is incised and the tumor is removed. We fasten each interlobar and segmental artery (small vessels) we encounter. As the renal artery is under our control, we can clamp it at any time in case of a problem. We have presented this technique in the US, receiving much interest. You can find the video of the surgical operation conducted using this zero-ischemia approach below.
To remove the renal tumor located deeper inside the kidney or in the hilus, a 20-minute renal ischemia would not be enough. Longer operational times are required. In this case, the only solution is to clamp the renal artery and place the sterile ice slush around the kidney. Thus, the kidney is cooled down. Its metabolic activity is lowered. The kidney can tolerate ischemia for up to 1 hour. After the tumor is removed, the incised renal ends are stitched. A drainage tube is placed. The incised skins and subcutaneous tissue are stitched. And the operation is completed.
Is partial nephrectomy is indicated for every kidney cancer?
The results of the multi-site, multi-national and multi-year comparative studies have demonstrated that partial nephrectomy is ideal for the renal tumors up to 4 cm (T1a). It is advisable for the tumors with sizes varying between 4 and 7 cm (T1b). Recent studies and some working groups recommend partial nephrectomy for compulsory cases with tumors with sizes varying between 7 and 10 cm (T2a) and even exceeding 10 cm (T2b). However, in case of tumors that have spread to the surrounding tissues and to the renal vein and even to the heart, radical nephrectomy should be performed to remove the entire kidney.
Is partial nephrectomy is performed for cases other than kidney cancer?
The kidneys may be injured in in-vehicle and extravehicular accidents. Most cases can be treated through bed rest. No surgical operation may be needed. If the kidney is torn into pieces, the damaged section is removed and the healthy renal tissues are preserved. In congenital anomalies where a kidney has two urinary systems, the upper part of the kidney may not function properly and get inflamed. The unhealthy section should be removed. In the patients having complex kidney stones, parts of the kidney may not function due to occlusion caused by the stones. These parts may be required to be removed through surgical techniques.
Postoperative phases of kidney cancer operations
Most complications (side effects) that develop after a kidney cancer operation are insignificant. The complications may increase depending on the location and size of the tumor. Greater care should be paid to complicated cases. The most serious complication is hemorrhage. This complication is rarely seen in experience centers. Severe postoperative hemorrhage may rarely be seen from the urinary tract in complicated cases.
The arterial and venous systems may be connected to each other due to the sutures. As the blood inside the artery has higher pressures, it may enter into the vein. This is termed as arteriovenous fistula. Interventional radiologists enter the blood vessels and stop the hemorrhage using closed surgical methods. It is a very rare complication.
Radical nephrectomy operation
Radical nephrectomy is an operation in which the cancerous kidney is removed completely. If the cancer has spread to the lymph nodes outside the kidney or to the inside of the inferior vena cava, partial nephrectomy (removal only of the tumor) cannot be performed. Radical nephrectomy (removal of the kidney completely) should be conducted. The kidney should be removed completely with the lymph nodes. The studies have demonstrated that even the positron emission tomography (PET) fails to detect definitely the lymph node metastasis of kidney cancers. Unnecessary PET imaging should not be performed. In radical nephrectomy, the kidney is removed completely along with the adipose issues around it. The grown lymph nodes which radiologically give the impression of metastasis must certainly be removed during the surgical operation. They should be sent to pathological examination.
In stage T3, kidney cancer may spread to the heart (atrium) via the inferior vena cava. Its location can be determined definitively using radiologically, especially MRI. In such cases, partial nephrectomy has no place. Radical nephrectomy is performed. The inferior vena cava is incised longitudinally. The tumor is cleared. The inferior vena cava is stitched. As seen in the image next to the page, in the cases where kidney cancer has spread to the heart, even the atrium is incised to remove the tumor. These patients can live for years thanks to a successful surgical operation. We have presented our radical nephrectomy vena cava and atrial thrombectomy series in advanced stage kidney cancers at an international congress in the US.