Kidney Cancer occurs due to the uncontrolled proliferation of cells within kidney tissue. Over time, these cells accumulate to form a tumor. The onset of cancer is triggered by certain changes in cell behavior, leading them to multiply uncontrollably.

A tumor that is cancerous or malignant has the potential to invade and damage other tissues and vital organs, a process known as metastasis.

Individuals aged between 65 and 74 are most frequently affected by kidney cancer. 

The likelihood of men developing this cancer is double that of women. Additionally, it is more prevalent among some ethnicities than others.

While kidney cancer is rarer in children, there are still 500 to 600 cases of Wilms tumor, a specific kind of kidney cancer, diagnosed annually in the United States only.

Kidney cancer constitutes approximately 3.7% of all cancer cases worldwide. Each year, for example, over 62,000 Americans are diagnosed with this type of cancer, with the risk increasing as people age.

Kidney Structure and Their Role

Kidneys are paired organs resembling beans in shape. Each kidney is roughly the size of a small fist and situated behind the abdominal organs, flanking the spine on each side.

It’s not uncommon for some individuals to have just one kidney, which may result from either congenital anomalies or medical conditions. Functioning well with a single kidney is feasible, provided that the remaining kidney is healthy.

The primary function of the kidneys is to filter and remove excess minerals, salt, and water from your bloodstream, which is then excreted as urine. On average, the kidneys process around 140 liters of blood daily, resulting in the production of approximately 1.7 liters of urine. 

This urine then travels through tubes known as ureters to the bladder, where it is stored until expulsion.

Within each kidney are over a million filtering structures known as nephrons. Each nephron contains a glomerulus that filters blood, and a tubule that discards waste while reclaiming vital substances back into the bloodstream.

Various Forms of Kidney Cancer

Kidney cancer manifests in several forms, including:

• Renal Cell Carcinoma (RCC): Predominant in adults, RCC makes up about 85% of all kidney cancer cases. It typically emerges as a single tumor in one kidney, but can occasionally involve both. This cancer originates from the cells lining the tubules of the kidneys, which are responsible for reabsorbing nutrients and fluids into the blood. Clear cell renal cell carcinoma (ccRCC) is the most frequent subtype of RCC.
• Transitional Cell Cancer: Comprising 6% to 7% of kidney cancers, transitional cell carcinoma primarily starts in the renal pelvis, the region where the ureter meets the main part of the kidney. It can also develop in the ureters or bladder.
• Renal Sarcoma: Representing a mere 1% of kidney cancers, renal sarcoma is the rarest type. It originates in the connective tissues of the kidneys and can metastasize to nearby organs and bones if left untreated.
• Wilms Tumor: Predominantly seen in children, Wilms tumor is the most common pediatric kidney cancer, accounting for about 5% of kidney cancer occurrences.

Symptoms of Kidney Cancer

In its initial stages, kidney cancer often presents without noticeable signs or symptoms. However, as the disease progresses, the following symptoms may emerge:

• Hematuria: Presence of blood in the urine, which might look pink, red, or similar to the color of cola.
• Persistent Pain: A continuous pain in the back or side that doesn’t subside.
• Decreased Appetite: A reduction in the desire to eat without an apparent cause.
• Unintended Weight Loss: Losing weight without trying or understanding why.
• Fatigue: Experiencing ongoing tiredness or weakness.
• Fever: Occurrence of unexplained fevers that are not linked to other known illnesses or infections.

What are the main factors contributing to kidney cancer?

The precise origins of kidney cancer are not fully understood, but several risk factors have been identified that may elevate the likelihood of developing the disease. These factors include:

• Smoking: Smokers face a higher risk of kidney cancer, and the risk escalates with the duration of smoking.
• Obesity: Being significantly overweight is a known risk factor, with higher levels of obesity correlating to increased risk.
• High blood pressure: Known as hypertension, this condition is associated with a heightened risk of kidney cancer.
• Family history: Individuals with relatives who have had kidney cancer may face an increased risk themselves.
• Radiation therapy: Women who have undergone radiation treatment for cancers of the reproductive system may have a marginally increased risk of kidney cancer.
• Genetic mutations: Alterations in certain genes can elevate the risk of kidney cancer development.
• Prolonged dialysis treatment: Used to clean blood when kidneys are not functioning adequately, long-term dialysis can be a risk factor.
• Tuberous sclerosis complex: This condition, characterized by seizures, intellectual disabilities, and tumor formation in various organs, can contribute to the risk.
• Von Hippel-Lindau disease (VHL): Individuals with this hereditary disorder, which causes noncancerous tumors in blood vessels, often in the eyes and brain, have a higher likelihood of developing kidney cancer.

Diagnosis of Kidney Masses

More than half of the cases involving kidney masses are detected incidentally. These masses are often discovered during routine screenings or consultations for unrelated health issues. 

If kidney issues are suspected, a primary care doctor may refer the patient to a urologist, a specialist in the urinary system.

There are no specific laboratory tests designed exclusively for detecting kidney masses. 

However, We can provide a variety of tests and procedures to assess kidney health and identify masses. These may include:

• A physical examination and medical history review.
• A basic or complete metabolic panel (CMP) to evaluate organ function.
• A complete blood count (CBC) to detect any signs of disease in the blood.
• Urinalysis to check for infections, blood, and protein in the urine.
• Tests for serum creatinine levels or other assessments of kidney function to ensure waste is being properly filtered.
• An ultrasound to produce images of the kidneys.
• CT scans and MRI scans to aid in diagnosing and staging kidney masses.
• Bone scans and chest X-rays to determine if the cancer has metastasized.
• A biopsy of the kidney mass to determine the type of tumor present.

Staging of Kidney Cancer

Cancer staging is a crucial part of treatment planning and is determined by assessing various aspects of the cancer. In kidney cancer, the stage is defined based on:

• The size and location of the tumor.
• Whether lymph nodes are involved.
• The extent of spread to other tissues and organs.

Healthcare providers use data from CT scans, MRI, and biopsies to ascertain the cancer stage. The stages of kidney cancer are:

1. Stage I: The tumor is confined to the kidney, measuring 7 centimeters (cm) or smaller. It has not spread to lymph nodes or other tissues. Lymph nodes are small structures that act as filters to trap germs and cancer cells and house immune cells.
2. Stage II: The tumor exceeds 7 cm in size but remains contained within the kidney. There is no spread to lymph nodes or other tissues.
3. Stage III: The cancer has extended to major blood vessels, such as the renal vein and inferior vena cava, or to the tissue around the kidney or nearby lymph nodes.
4. Stage IV: The cancer has metastasized beyond the kidney, possibly reaching the adrenal gland (located on top of the kidney), distant lymph nodes, or other organs.

Additionally, kidney tumors are graded based on how abnormal the cells appear under a microscope and how quickly they are likely to grow. 

High-grade tumors, characterized by cells that look quite different from normal cells and divide rapidly, tend to grow and spread faster than low-grade tumors.

Approaches to Kidney Cancer Treatment:

After receiving a kidney cancer diagnosis and determining the stage, we will be able to develop a treatment strategy. It’s beneficial to collect information to make an informed decision regarding your treatment. 

Our specialists such as urologists, medical or radiation oncologists, or surgeons will be able to help the patient have a better understanding of the case and find the best way for treatment.

Many individuals find it valuable to seek a second opinion on their kidney cancer diagnosis and proposed treatment plan before starting treatment.

Kidney cancer is known to sometimes experience spontaneous regression, where it reverts to an earlier stage. However, this occurrence is relatively rare, with an estimated incidence of around 0.5%.

There are various established treatment methods for kidney cancer. Surgery is often the initial step. Even after completely removing the tumor through surgery, your doctor might recommend additional treatment to eliminate any unseen remaining cancer cells.

Surgical Options for Kidney Cancer

The type of surgery for kidney cancer varies depending on the cancer’s stage. Here are the primary surgical methods:

• Radical Nephrectomy: This is the most common surgery for kidney cancer, involving the removal of the kidney, adrenal gland, surrounding tissue, and often nearby lymph nodes. It can now be performed with minimal invasion using a laparoscope through a small incision.
• Simple Nephrectomy: This procedure involves only the removal of the kidney.
• Partial Nephrectomy: Here, the surgeon removes the cancer within the kidney and some surrounding tissue. This is typically for patients with smaller tumors (under 4 cm) or where a radical nephrectomy might adversely affect the remaining kidney.

It’s possible to live with only a part of one functioning kidney. However, if both kidneys are removed or non-functional, you’ll require a machine (dialysis) to purify your blood or a kidney transplant. 

Transplants are feasible if the cancer is confined to the kidney and a donor kidney is available.

If surgery isn’t an option for your kidney cancer, your doctor might recommend alternative treatments to target the tumor:

• Cryotherapy: This technique uses extreme cold to destroy the tumor.
• Radiofrequency Ablation: This method employs high-energy radio waves to eliminate the tumor.
• Arterial Embolization: This involves inserting material into an artery leading to the kidney to block blood flow to the tumor, potentially shrinking it before surgery.

Biologic Therapy:

Biologic therapy leverages the power of your immune system to combat cancer. It works by enhancing, directing, or rejuvenating your body’s inherent defenses against cancerous cells. 

The substances used in this therapy are either produced naturally by the body or synthesized in a laboratory. For metastatic kidney cancer, examples of biologic therapy include interferon alpha and interleukin-2. 

Currently, numerous new immunotherapies are under active investigation for the treatment of kidney cancer.

Targeted Therapy:

Targeted therapy employs drugs or substances specifically designed to identify and attack cancer cells while minimizing harm to normal cells. One form of targeted therapy involves anti-angiogenic agents, which obstruct the blood vessels that nourish tumors, leading to their shrinkage or halting their growth. 

Another variant employs multikinase inhibitors or tyrosine kinase inhibitors. These oral medications inhibit an enzyme pathway that facilitates the growth of cancer cells. 

A third category of targeted therapy includes m-TOR inhibitors, available in both oral and intravenous forms. 

They block a pathway that assists in blood vessel formation aiding tumor cell growth. Each of these drugs plays a distinct role in managing advanced kidney cancer.

Radiation Therapy:

Radiation therapy is often employed for symptom management in kidney cancer or for patients who are not candidates for surgery. 

This treatment involves the use of high-energy X-rays or other forms of radiation to eliminate cancer cells or inhibit their growth. 

In external radiation therapy, the radiation is directed towards the cancer from a machine located outside the body. It’s a non-invasive method to target and reduce cancer cells.

Chemotherapy:

Chemotherapy utilizes drugs designed to destroy cancer cells or prevent their proliferation. 

While it is generally less effective for kidney cancer compared to other cancer types, it finds specific use in a variant of kidney cancer characterized by the presence of spindle cells, known as the sarcomatoid variant.

 In these cases, chemotherapy can be a critical part of the treatment plan, focusing on targeting and managing this particular type of kidney cancer.

Prevention

To lower your risk of kidney cancer, it’s important to focus on overall health improvement. Here are some strategies to consider:

1. Stop smoking: If you’re a smoker, quitting is crucial. There are various aids available to help, including support programs, medications, and nicotine replacement therapies. Consult with your doctor about wanting to quit and explore the options together.
2. Maintain a healthy weight: Aim to keep your weight within a healthy range. If you’re currently overweight or obese, try to reduce your daily calorie intake and engage in physical activity most days of the week. Your doctor can provide additional healthy weight loss strategies.
3. Manage high blood pressure: Have your blood pressure checked at your next medical appointment. If it’s high, discuss with your doctor ways to lower it. Lifestyle changes like regular exercise, weight loss, and dietary modifications can be effective. In some cases, medication may be necessary to control high blood pressure.

Takeaway

Understanding the symptoms and risk factors of kidney cancer is crucial, as early detection can make a significant difference. There are numerous treatment options for kidney cancer when it’s identified early.

Prevention is key, and outweighs the benefits of treatment. To lower your risk, focus on lifestyle changes. Smoking is a major risk factor for kidney cancer, so quitting smoking is vital. 

If you’ve never smoked, it’s best to avoid starting. Remember, the risk of kidney cancer decreases after quitting smoking, and it’s beneficial to quit even after a cancer diagnosis.

Be informed about any chemicals or substances you might be exposed to in your workplace. Adhere to safety guidelines when handling these chemicals. 

Additionally, a healthy diet and maintaining a normal weight are important preventative measures, as obesity increases the risk for various types of cancer, including kidney cancer.