Kidney Cancer

Kidney cancer is the formation of a malignant tumor (mass) that occurs when cells in the kidney tissue, which filters the blood and removes harmful substances from the body, undergo structural deterioration and multiply uncontrollably. Referred to in the medical literature as renal cell carcinoma, this condition begins when the organ departs from its healthy cell renewal cycle and exhibits abnormal cellular growth. This abnormality developing in the body’s main filtration center gradually occupies physical space within the organ’s structure, transforming a problem that begins at the cellular level into a systemic disease. By nature, this oncological process usually begins silently, yet it is a biological condition that can be successfully managed through current medical approaches and appropriate healthcare strategies.

What is kidney cancer?

Kidney cancer is a malignant tumor structure originating from the tubular systems of the kidney that filter blood and form urine. The disease usually begins in the cells lining the inner surface of these microscopic tubules. This uncontrolled growth, which initially occurs at the cellular level, gradually combines to form a solid mass within the kidney tissue. Because the kidneys are located at the back of the abdominal cavity and within a highly flexible layer of fatty tissue, a growing mass can comfortably find space for itself for a long time.

This prevents the disease from pressing on surrounding organs or nerves during its early stages. Therefore, the tumor may continue to grow silently for months or even years without causing the patient any discomfort. Over time, it begins to stretch the outer membrane of the kidney and infiltrate the blood vessels or urinary collecting structures within the kidney. If it is not detected and treated at these stages, cancer cells may spread through the blood or lymphatic system to other parts of the body, particularly the lungs, bones, or liver, making the course of the disease much more complex.

How common is kidney cancer in the population and who is at risk?

When malignant tumors encountered in adulthood are examined, kidney tumors account for approximately two and a half percent of all cancer cases. According to statistical data, this disease is encountered each year in one out of every ten thousand people in the population. This disease largely appears as a problem of advanced age; the vast majority of individuals diagnosed are between fifty and seventy years old.

From the perspective of sex, the likelihood of the disease occurring in men is approximately two to three times higher than in women. It is believed that environmental toxins to which men are exposed in working life, tobacco use habits, and differences in hormonal structure underlie this difference. Particularly in industrialized societies, a slight but steady increase in the incidence of the disease has been observed over the years due to longer average life expectancy and changing dietary habits.

What are the main risk factors leading to the development of kidney cancer?

Although it is impossible to attribute the onset of cancer to a single cause, there are very clear environmental and physical factors that disrupt cell structure and create a basis for the disease. Many of these factors are conditions that individuals can actually control through lifestyle changes.

The main risk factors involved in the development of the disease are:

• Smoking
• Obesity
• High blood pressure
• Advanced age
• Asbestos exposure
• Heavy metal exposure
• Long-term dialysis treatment
• Sedentary lifestyle

Smoking, included in this list, is unquestionably the strongest risk-increasing factor. Hundreds of carcinogenic substances in tobacco smoke enter the bloodstream through the lungs and come into direct contact with kidney cells when they reach the kidneys to be filtered. This intense toxic contact triggers cellular deterioration. Likewise, obesity creates a state of chronic inflammation in the body and disrupts hormonal balance, paving the way for cellular mutations. High blood pressure, particularly hypertension, causes tissue damage by continuously placing stress on the delicate capillaries of the kidney. Heavy metal and chemical exposures seen in individuals working in the steel, petroleum, and paint industries also accumulate in kidney tissue over time and create toxic effects.

Does familial or genetic inheritance play a role in the development of kidney cancer?

Although the vast majority of disease cases are associated with environmental factors that develop later in life, the role of genetic inheritance certainly cannot be ignored. In approximately five to ten percent of all cases, genetic defects inherited directly from the family are the main cause of the disease. Individuals with a family history of kidney tumors, particularly in first-degree relatives such as a mother, father, or sibling, have a substantially higher lifetime risk of encountering this disease compared with the rest of the population.

In particular, the congenital absence or defect of certain protective genes that keep cell growth under control causes kidney cells to become tumorous much more easily. One of the best-known examples in the medical world is Von Hippel-Lindau syndrome. Individuals with this genetic disorder frequently develop cysts and tumors not only in the kidneys but also in different parts of the body. Therefore, it is extremely important for individuals with kidney disease beginning at an early age in more than one family member to undergo check-ups at regular intervals.

What are the main types of kidney cancer according to their cellular origin?

Kidney cancer is not a single type of disease. It is divided into many subtypes with different characteristics according to the type of cell from which the tumor originates and its genetic arrangement under the microscope. Determining these types is a critical step in predicting how rapidly the disease will progress and selecting the most appropriate treatment.

The main types identified under microscopic examination are:

• Clear cell
• Papillary
• Chromophobe
• Translocation
• Oncocytoma
• Papillary adenoma
• Metanephric adenoma

The clear cell type listed above is the most common form, seen in approximately seventy to eighty percent of all patients. Because the cells are filled with fat and sugar molecules, they appear clear like water droplets under the microscope. Unfortunately, it is also the type with the highest potential to spread. The papillary type, which is the second most common, forms finger-like projections under the microscope and generally follows a calmer course. The chromophobe type has highly distinct cell walls and grows more slowly than the others. While the translocation type on the list has an aggressive structure and is seen particularly in younger individuals, the masses called oncocytoma, papillary adenoma, and metanephric adenoma are completely benign, do not spread to other organs, and do not pose a serious threat to health.

Which symptoms does kidney cancer cause in the advanced stages of the disease?

The completely silent course of the early stages of the disease usually causes patients to continue their daily lives without feeling anything. Many patients learn completely by chance that they have a mass in their kidney as a result of ultrasonography performed for a gallbladder complaint, simple back pain, or routine health screening. However, when the tumor grows too large for its capsule and begins damaging surrounding tissues, the body starts sending warning signals.

The main symptoms encountered as the disease progresses are:

• Blood in the urine
• Side pain
• A feeling of a mass in the abdomen
• Weight loss
• Loss of appetite
• Persistent fatigue
• Unexplained fever
• Night sweats

Blood seen in the urine may sometimes be visibly pink, red, or tea-colored, while at other times it is detected only microscopically in laboratory tests. If the blood forms clots and attempts to pass through the urinary tract, it may cause extremely severe pain resembling the passage of a kidney stone. As the tumor grows, it stretches the kidney capsule and creates persistent, uncomfortable, dull pain in the lower back and sides of the waist. When the mass reaches a very large size, the patient may feel a hard swelling in the abdominal region with their own hand.

How does hormonal balance change in kidney cancer patients and what is Stauffer syndrome?

Cancer cells sometimes do more than invade the tissue in which they are located; they take control of the body’s hormonal system and begin producing very different chemical substances. These substances released from tumor cells into the bloodstream cause complex clinical conditions called paraneoplastic syndromes. For example, the tumor may continuously send false signals to the body to produce blood, causing the blood to thicken, or disrupt calcium balance, causing calcium levels in the blood to rise dangerously.

One of the most interesting of these systemic effects is Stauffer syndrome. In this syndrome, although cancer cells have not actually spread to the liver or caused any physical damage there, the functioning of the liver becomes completely disrupted. The mass in the kidney releases large amounts of inflammation-triggering signaling molecules into the bloodstream. These molecules travel directly to the liver and disrupt the organ’s enzyme production and the regulation of the bile ducts. While the patient experiences unexplained fever and fatigue, blood tests show very high liver values. However, imaging shows that the liver is completely clear. The remarkable aspect is that when the tumor in the kidney is surgically removed from the body, the release of those toxic signals into the bloodstream stops, allowing the liver to completely recover on its own and return to normal function within weeks.

How are imaging methods used in the diagnosis of kidney cancer?

When a mass in the kidney is suspected, the first step taken in medical practice is generally laboratory tests and rapid imaging methods. Although comprehensive blood and urine tests provide a general idea about the working capacity of the organs, radiological imaging technology is needed to see the tumor and understand its structure.

Ultrasonography, a rapid method that does not involve radiation, is an excellent starting point for distinguishing whether the mass is merely a harmless fluid-filled cyst or solid and suspicious tissue. However, computed tomography performed with medication administered intravenously, known as contrast material, is used for definitive diagnosis, treatment planning, and viewing the depth of the tumor within the kidney with millimetric precision. Tomography creates a three-dimensional map of the kidney in very thin sections, showing perfectly how close the mass is to the main blood vessels and whether it has spread to surrounding lymph nodes. If the patient’s kidney functions are weak or they are allergic to the medication used in tomography, magnetic resonance imaging (MRI) systems that provide equally clear information are used.

Is biopsy always necessary for a definitive diagnosis of kidney cancer?

In many organs suspected of cancer, such as in breast, thyroid, or prostate diseases, taking a tissue sample from the mass with a needle, known as a biopsy, is a mandatory and routine procedure for confirming the diagnosis. However, the situation is quite different in kidney masses. The resolution of modern tomography and MRI devices is so high that radiological examinations can determine whether a solid mass is cancerous with more than ninety percent accuracy. Therefore, in most patients, a decision for surgery can be made directly without the need for a biopsy.

However, special situations in which biopsy should be performed are as follows:

• Active surveillance plan
• Before thermal ablation
• Advanced-stage disease
• Preparation for systemic drug treatment
• High surgical risk
• Suspicion of cancer from another organ

If the mass is very small and, due to the patient’s age or additional diseases, a decision is made to monitor only the growth of the mass instead of performing immediate surgery, known as active surveillance, biopsy is essential to determine how aggressive that mass is. Likewise, if the patient will undergo a nonsurgical needle-based burning or freezing procedure, the type of tissue must be proven before the procedure. If the disease has spread throughout the body and systemic medications similar to chemotherapy will be used, the complete genetic identity of the tumor should be determined through biopsy to identify which medication will be effective.

What are the main surgical methods applied in localized kidney cancer cases?

If the cancer cells are still confined only to the kidney tissue and have not spread to surrounding organs, the most definitive and permanent treatment of the disease is the surgical removal of the tumorous area from the body. In cases where the mass is very large and located in the exact center of the kidney, invading all the main blood vessels, a procedure called radical nephrectomy is applied. In this operation, the diseased kidney is completely removed together with the protective fatty sheath layer surrounding it.

The human body has a remarkable ability to adapt, allowing a person to continue living throughout life without problems with a single healthy kidney by increasing that kidney’s working capacity, known as hypertrophy. Today, these procedures are performed laparoscopically, through minimally invasive surgery, using cameras and thin instruments inserted through several small openings measuring only half a centimeter rather than large incisions in the patient’s abdomen. Minimally invasive surgery dramatically improves postoperative comfort, reduces bleeding, and allows the individual to return to daily life within a few days rather than weeks.

Is it possible to treat kidney cancer without removing the entire kidney?

The highest point reached by modern surgery is not only to eliminate the disease but also to preserve healthy tissue to the greatest possible extent. If the tumor is below a certain size, generally between 4 and 7 centimeters, and located in a suitable part of the kidney, nephron-sparing surgery, known as partial nephrectomy, is performed, in which only the tumorous tissue is removed and the healthy part of the kidney is left in the patient. This method is lifesaving, particularly in individuals born with a single kidney, those with tumors in both kidneys, or those who are at risk of kidney failure in the future due to conditions such as high blood pressure or diabetes.

This surgery is a challenging process requiring a very high level of skill. To prevent the patient from being harmed by blood loss while removing the tumor, the main vessel supplying blood to the kidney is temporarily closed with small clamps at the most critical moment of the operation. The period during which the blood supply to the kidney is stopped is called warm ischemia time. To prevent the tissues from dying due to oxygen deprivation, this period must be kept to a maximum of twenty to twenty-five minutes. Within this short period, the surgeon must cut out and remove the tumor, suture the cavity created in the kidney with special threads to stop the bleeding, and reopen the vessel on time.

What advantages does robotic surgery provide to patients in kidney cancer operations?

In these difficult kidney-preserving surgeries, where surgeons race against time and millimetric precision is required, robotic surgery systems have become the medical world’s greatest technological assistant in recent years. In the robotic surgery system, instead of standing at the patient’s bedside, the surgeon sits at a special console in the corner of the operating room and controls the device from there using finger movements.

The three-dimensional, high-resolution camera provided by the system magnifies the organ by more than ten times, allowing even the finest capillary vessels in the surgical area to be seen perfectly. The robotic arms can perform maneuvers that the human hand cannot perform because of anatomical limitations, rotate almost completely around themselves, and filter out and entirely eliminate the surgeon’s natural hand tremor. As a result, the process of suturing the open tissue after the tumor has been removed from the kidney becomes remarkably faster. The limited warm ischemia time can be managed very comfortably, and kidney functions are successfully preserved. Because the incisions are small and the tissues experience less trauma, patients require fewer painkillers, and the duration of hospital stay is significantly shortened.

What are the nonsurgical methods for kidney cancer in patients who cannot undergo surgery?

Sometimes the patient may be very old, or severe heart disease or respiratory problems may make receiving anesthesia dangerous. In such situations, undergoing surgery may pose a greater risk to the patient’s life than the cancer itself. If the mass is small in diameter, special ablation treatments applied externally without administering anesthesia or cutting the body can be performed on these patients with great confidence.

The main nonsurgical methods used in these patients are:

• Cryoablation
• Radiofrequency ablation
• Microwave ablation
• Active surveillance

These methods work on the principle of placing a special needle through the skin into the cancerous tissue under ultrasound or tomography guidance. In cryoablation, the inside of the tumor is frozen to temperatures as low as minus eighty degrees using highly pressurized special gases delivered through the needle tip, and the ice ball formed by the cancer cells ruptures and dies. In radiofrequency and microwave methods, the opposite principle is used: high electrical or electromagnetic vibrations heat the tissue to temperatures of up to one hundred degrees, destroying the cells through disruption of their protein structures. If the mass grows very slowly and the patient’s general condition does not allow any intervention, monitoring the behavior of the mass through regular imaging alone, known as active surveillance, is also a highly valid option.

How should kidney cancer follow-up be performed after treatment?

The removal of cancer from the kidney does not mean that the process is completely over. Regardless of which treatment method is applied, establishing a strict follow-up routine after the procedure to detect recurrences early is of vital importance. During the first weeks after the procedure, the body needs to recover, plenty of fluids should be consumed to preserve kidney functions, and heavy physical activities that increase abdominal pressure should be avoided.

The warning signs to watch for after surgery are:

• High fever
• Severe pain
• Blood clots in the urine
• Unexplained weight loss
• Shortness of breath
• Persistent cough

Your doctor will call you for check-ups at regular intervals. Six weeks after needle-based treatments such as ablation, the first detailed imaging studies are performed to confirm whether the tumor area has completely died. After successful surgeries, abdominal tomography, chest X-ray, and kidney function measurements are performed every six months during the first years and once a year in subsequent years. Only through this disciplined follow-up plan can we detect at a very early stage whether the tumor has secretly begun growing again in different areas such as the lungs or liver.

Which modern drug treatments are applied in patients with advanced metastatic kidney cancer?

When kidney cancer is not diagnosed early and spreads to other organs, it demonstrates a highly stubborn and resistant response to conventional cancer treatments such as chemotherapy or radiation therapy. However, tremendous advances in medical science in recent years have introduced powerful new treatment options for patients at this challenging stage.

Targeted smart medications are among the leading examples of these new-generation treatments. Cancer cells tend to continuously form new blood vessels to nourish themselves so that they can grow rapidly. Smart medications interrupt the tumor’s signals for forming these new vessels, effectively depriving it of nutrients and oxygen and causing it to shrink. Another groundbreaking treatment method is immunotherapy. Cancer cells normally wear a kind of invisibility cloak to hide from the body’s defense system. Immunotherapy medications disrupt the hiding mechanisms of these cells, allowing the patient’s own natural immune system cells to find and destroy the tumor.

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