It is a growth of cells that starts in the kidneys. In adults, the cancer in the lining of tiny tubes in the kidney called renal tubules (renal cell carcinoma) is the most common type of kidney cancer. Young children are more likely to develop a kind of kidney cancer called Wilms’ tumor.

Statistics:

Kidney cancer is the 12th most common cancer worldwide, with reports recording over 400,000 cases annually. In India, kidney cancer accounts for ~1.3% of all cancer cases, with an incidence of 2 per 100,000 males and 1 per 100,000 females, according to the GLOBOCAN 2020 report.

RCC (Renal cell carcinoma) accounts for approximately 85% of all malignant kidney tumors.

PC (Papillary carcinoma) constitutes roughly 10% to 15% of the known cases of kidney cancer.

It has a high mortality rate, with about 155,900 deaths annually worldwide.

Types of kidney cancer:

• Renal Cell Carcinoma (RCC): It is the most common type of kidney cancer, accounting for approximately 85% of all malignant kidney tumors. In RCC, cancerous (malignant) cells develop in the lining of the kidney tubules. RCC typically grows as a single mass. However, there are cases where a kidney may contain more than one tumor, or tumors are found in both kidneys at the same time.
• Clear Cell Carcinoma: Approximately 75% of individual cells appear very pale or clear under the microscope.
• Papillary Carcinoma: approximately 10% to 15% of people have this form. These cancers form little finger-like projections (called papillae). There are two types of papillary tumors:
  • Chromophobe: approximately 5% of cases. These cells are larger and have prominent cell borders and can appear pink or clear.
  • Clear Cell Papillary Carcinoma: approximately 2-4% of all cases. A new subtype with features of both papillary and clear subtypes. These are often less aggressive.
• Collecting Duct Carcinoma: approximately 1% of all cases. Aggressive type arising from the collecting system that forms irregular tubules.
• Medullary Cancer: approximately 1% of cases. A very aggressive type often occurring in young African Americans with sickle trait.
• Urothelial Carcinoma: Arises from the renal pelvis and resembles bladder cancer cells. It is genetically similar to urothelial cancer of the urinary bladder and has similar risk factors such as cigarette smoking and occupational exposures to certain cancer-causing chemicals.
• Wilms Tumor: A rare pediatric malignancy in children between the ages of 2-5.
• Renal Sarcoma: A rare type of kidney cancer (< 1%) arising from the connective tissue of the kidney.

Location:

The kidneys are two bean-shaped organs located behind the abdominal organs, with one kidney on each side of the spine.

The kidney has tiny tubes called renal tubules. Renal cell carcinoma (RCC) and Papillary renal cell carcinoma (PRCC) both usually start in the lining of these tubes.

Translocation renal cell carcinoma (TRCC) develops inside the kidneys themselves.

Stages:

Kidney cancer stages range from I (1) to IV (4). The lower the number, the less the cancer has spread.

Information used to determine the stage:

• Size of the tumor (T): how large is the cancer? Is it contained inside the kidney? Has it grown into other organs too?
• Spread of nearby lymph nodes (N): Has the cancer spread to the nearby lymph nodes?
• Metastasis (M): Has the cancer spread to distant lymph nodes or organs?

Diagnosis:

Following are the factors taken into consideration during diagnosis-

Symptoms:

Kidney cancer doesn't usually cause symptoms at first. In time, signs and symptoms may develop, including:

• Blood in the urine, which may appear pink, red, or brownish.
• Loss of appetite.
• Pain in the side or back that doesn't go away.
• Tiredness.
• Unexplained weight loss.

Risk Factors and Causes:

Factors that may increase the risk of kidney cancer include-

• Older age: The risk of kidney cancer increases with age.
• Smoking tobacco: People who smoke have a greater risk of kidney cancer than those who don't. The risk decreases after quitting.
• Obesity: People who are obese have a higher risk of kidney cancer than people who are considered to have a healthy weight.
• High blood pressure: High blood pressure, also called hypertension, increases the risk of kidney cancer.
• Certain inherited conditions: People who are born with certain inherited conditions may have an increased risk of kidney cancer. These conditions may include von Hippel-Lindau disease, Birt-Hogg-Dube syndrome, tuberous sclerosis complex, hereditary papillary renal cell carcinoma, and familial renal cancer.
• Family history of kidney cancer: The risk of kidney cancer is higher if a blood relative, such as a parent or sibling, has had the disease.

Precautionary measures:

• Drinking alcohol in moderation, if at all. For healthy adults, that means up to one drink a day for women and up to two drinks a day for men.
• Choosing a healthy diet with a variety of fruits and vegetables so as to receive plenty of vitamins. Large doses of vitamins in pill form, however, should be avoided as they may be harmful.
• Aiming for at least 30 minutes of exercise on most days of the week.
• Maintaining a healthy weight
• Not smoking
• Controlling high blood pressure

Treatment:

For most cancers confined to the kidney, surgery is the first treatment. The goal of surgery is to remove the cancer while preserving kidney function, when possible. Operations used to treat kidney cancer include:

• Removing the affected kidney: A complete nephrectomy, also known as a radical nephrectomy, involves removing the entire kidney and a border of healthy tissue around it. Nearby tissues such as the lymph nodes, adrenal gland or other structures also may be removed.
• Removing the cancer from the kidney: A partial nephrectomy involves removing the cancer and a small margin of healthy tissue that surrounds it rather than the entire kidney. This procedure, also called kidney-sparing or nephron-sparing surgery, is a common treatment for small kidney cancers and for patients with only one kidney.
• Cryoablation: It is a treatment performed by freezing cancer cells. During cryoablation, a special hollow needle is inserted through the skin and into the kidney cancer using ultrasound or other image guidance. Cold gas in the needle is used to freeze the cancer cells.
• Radiofrequency ablation: It is a treatment done by heating cancer cells. During radiofrequency ablation, a special probe is inserted through the skin and into the kidney cancer using ultrasound or other imaging to guide placement of the probe. An electrical current is run through the needle and into the cancer cells. This causes the cells to heat up or burn.
• Radiation therapy: It treats cancer with powerful energy beams. The energy can come from X-rays, protons or other sources, pointed onto precise points of the body.
• Targeted therapy: It is a treatment that uses medicines that attack specific chemicals in the cancer cells. By blocking these chemicals, targeted treatments can cause cancer cells to die.
• Chemotherapy: It treats cancer with strong medicines. Usually, kidney cancers are resistant to chemotherapy. However, it may be used for certain rare types of kidney cancer.

Side effects:

All treatments for kidney cancer can have side effects. Kidney cancer and its treatment can sometimes lead to long term, or even permanent effects. Some common symptoms are-

• Flu-like symptoms, such as fever, chills, muscle and joint pain.
• Skin problems including rash and dryness.
• Loss of appetite
• Severe fatigue
• Nausea and vomiting
• Low blood pressure
• Diarrhea
• Surgery can lead to scar tissue, trouble in controlling flow of urine, bowel changes, and lymphoedema (if lymph nodes are removed).