Frequently Asked Questions About Kidney Cancer

Introduction

Kidney cancer, also known as renal cancer, is a type of cancer that occurs in the kidneys. It develops when kidney cells start growing abnormally, out of control. Each year, around 400,000 people are diagnosed with kidney cancer, and this number is estimated to rise over the next decade.¹ 

Cancers of the kidney can give rise to blood in urine, abdominal and back pain, and high blood pressure, and are commonly detected using imaging studies and biopsies. Although there are many different options to treat cancers of the kidney, early diagnosis is essential for a better outcome.

What are the kidneys?

Kidneys are two small bean-shaped organs in your tummy beside the spine on each side, just beneath the ribs.² They filter about half a cup of blood every minute and remove excess water, ions, and waste to produce urine to maintain electrolyte and water balance. In addition, they also play a vital role in maintaining a healthy blood pressure, helping in producing red blood cells and keeping the bones healthy.³ 

How does kidney cancer occur?

Signals sent from genes can regulate and control the growth and multiplication of normal healthy cells. However, mutations of these genes can make cells (cancer cells) ignore these instructions on when to start and stop growing and dividing. Cancer cells also destroy surrounding tissue and spread into other distant sites of the body, like the liver, lungs, and brain, a phenomenon called metastasis.⁵ 

What are the current statistics of kidney cancer?

Kidney cancers are the 14th most common type of cancer worldwide. Males are two times more likely to develop kidney cancer compared to females. It affects a higher proportion of those in high-income countries than middle or low-income countries and is significantly more common in black people than in caucasians.¹

What are the different types of kidney cancers? 

There are different types of kidney cancers. These include:

Renal cell carcinoma

Renal cell carcinoma is the most common type of renal cancer. It occurs in 9 out of 10 people who are affected with cancers of the kidney, and is responsible for 2 to 3% of all adult cancers. These can be further divided into different types according to how the growth appears to the naked eye and under the microscope, like clear cell carcinoma, papillary renal cell carcinoma, and chromophobe renal carcinoma.⁴

Transitional cell carcinoma

These cancers occur in the pelvis of the kidney, which is the central part of the kidney that stores urine before it passes into the ureters - the tubes that connect the kidneys with the bladder. It accounts for approximately 7% of all kidney cancers.⁶ Transitional cell cancers can also occur in the ureters and bladder.

Renal sarcoma

Only 1% of kidney cancers are renal sarcomas.⁷ These growths arise from connective tissue of the kidney (muscles, fat, and blood vessels) rather than cells of the nephron.

Wilms tumor

Wilms tumour, also called nephroblastoma, is the most common kidney cancer in children. Also, it is the fourth most common type of cancer in the pediatric population. It is seen in children younger than 5 years of age. Wilms tumour is  associated with specific syndromes that give rise to other problems of the kidneys, genitalia, and eyes, etc.⁸

What is the cause of kidney cancer?

The exact reason why kidney cancers develop is not yet known. However, studies have indicated some factors that can increase the chance of developing kidney cancers. These are:⁴

• Smoking
• Obesity
• High blood pressure 
• Long-term kidney issues (Chronic kidney disease)
• Long-term dialysis
• Occupational exposure to chemicals like trichloroethylene
• Hereditary conditions like Von Hippel-Lindau (VHL) Syndrome and Tuberous Sclerosis

What are the symptoms of kidney cancer?

Kidney cancers usually cause symptoms only in late stages, and as many as 50% of the cases are detected incidentally on scans performed for other reasons. Those with abnormal growths in the kidneys may experience:⁴

• Passage of blood in urine (hematuria)
• Flank pain
• Flank fullness
• Abdominal mass
• Fever
• Night sweats
• Weight loss
• Feeling unwell (Malaise)
• Symptoms of anaemia, like exertional tiredness, difficulty in breathing, chest pain
• Elevated blood pressure

A classic symptom triad of flank pain, hematuria, and flank fullness is described, which is seen only in 10-15% of people with kidney cancer.⁴

Production of hormone-like substances by the cancer cells can result in some symptoms, which are called paraneoplastic manifestations.⁹ These are:

• Erythrocytosis (increased red blood cells)
• Hypercalcemia (increased calcium levels)
• Cushing’s syndrome

One in three individuals with kidney cancer only presents when the spread of the cancer to distant sites has occurred (metastasis). Common sites where cancer from the kidney spreads are the lungs, bone, liver, and brain.¹⁰

How is kidney cancer diagnosed?

Blood and urine tests, imaging studies and biopsies are utilised in the detection of kidney cancers.¹¹

• Urine analysis: Red blood cells in urine (especially when not seen to the naked eye) can be detected through urine tests.  Urine cytology to check the presence of cancer cells in urine is typically done once kidney cancer is suspected
• Blood tests: A full blood count (FBC) may show the presence of anaemia or erythrocytosis (i.e. the change in number of RBCs). Renal function tests (RFT) to detect serum creatinine levels and serum electrolyte levels are commonly performed to identify any derangements which could signal impairment in kidney function. Blood tests to check liver enzyme levels and calcium levels may be done if complications are suspected
• Ultrasound scan (USS): USS uses high-frequency sound waves to create an image of the internal organs. This is used as the initial imaging modality
• Computed tomography (CT) scan: CT scans use X-rays to create detailed images of the kidneys and other organs. These scans help confirm the diagnosis of cancer and check the regional and distant spread (i.e. stage of the disease)
• Kidney biopsy - During a biopsy, a thin needle is introduced under the guidance of ultrasound or CT and a small tissue piece from the mass is removed. The tissue piece will be examined under the microscope by a pathologist to check for the presence of cancer cells. However, not all kidney cancers require biopsy. The decision to do a biopsy depends on the size and location of the growth, the patient's general health condition, and the findings of imaging studies

What are the treatment options for kidney cancer?

There are many treatment options for kidney cancers, and the best choice depends on the size of the growth and how far it has spread. 

Surgical resection

Surgical removal of the complete kidney or a part of it with the tumour is a common management option. Partial nephrectomy involves excision of part of the kidney with the growth while sparing the healthy parts. It is performed in cases where the growth is less than 7cm. Radical nephrectomy is done for larger cancers (>7cm) and those that have spread regionally, in which surrounding fatty and connective tissue structures are removed together with the kidney. Both types of surgeries can be done with an open incision, laparoscopically or with robotic assistance.

Radiotherapy

High-energy X-rays and other types of radiation are delivered by a machine towards the area of the kidney with cancer cells.

Immunotherapy

The human immune system is capable of screening for abnormal cells and destroying them. But cancer cells develop mechanisms by which they can evade this normal screening process. Immunotherapy aims to potentiate immune cells to destroy cancer cells. Examples of immunotherapy for renal cancers include avelumab, ipilimumab, and nivolumab.

Targeted therapy

These drugs are capable of directly attacking cancer cells and disrupting key mechanisms to control the growth and spread of cancer cells. Axitinib, lenvatinib, and sorafenib are some targeted drugs used in kidney cancer.

Chemotherapy

Chemotherapeutic drugs typically used in other cancers do not work for kidney cancers and are only used in specific situations.¹²

Can kidney cancer be prevented?

The occurrence of kidney cancers cannot be prevented. However, it is possible to minimise the risk by addressing the known risk factors. Some lifestyle changes that can reduce this risk are:

• Quitting smoking
• Consuming a balanced, healthy diet
• Maintaining a healthy body weight
• Prevention and control of other medical conditions like high blood pressure and high blood sugar
• Limiting exposure to harmful chemicals¹³

How can kidney cancers be identified early?

For people with an average risk of kidney cancers, special screening tests have not been found to have increased benefits and therefore are not recommended. But, urine tests, as part of regular health checkups, and imaging studies done for other reasons may give clues to renal cancers.

Those with hereditary conditions who are at an increased risk for kidney cancers need to undergo regular physical exams along with imaging studies for early detection of abnormal growths of the kidneys. If you have a history of kidney cancer in your family, you may be recommended to undergo genetic tests.¹⁴

What is the prognosis for kidney cancer?

Prognosis of kidney cancer is dependent on the stage of the disease at diagnosis. Generally, 75 individuals out of 100 with kidney cancer are expected to survive 5 years after the diagnosis.⁴ If the condition is detected early (stage 1) this number rises to 90 out of 100. With late stages, this number falls. 

Factors not directly related to the growth, like age, general health of the individual and the response to treatment, affect the survival. 

How can I support a loved one with kidney cancer?

Getting to know that you have cancer in your kidney can have a huge psychological and emotional impact on an individual. It can be overwhelming to their family, friends and loved ones. Maintaining frequent contact with these individuals by sending texts, calling, or visiting them is important to let them know they are not alone in the journey. 

The needs of these people differ greatly. Some might need support with daily activities like groceries, some with work and others may need help with treatment financially. It is important to know this so you can support them the best.  

Connecting them with local support groups can stimulate them to make new connections with others going through similar experiences.  

Summary

• Kidney cancers occur when cells of the kidneys start to ignore normal growth signals to grow and divide uncontrollably
• These cells acquire the ability to destroy normal areas of the kidney and spread to distant sites like the lungs, liver, and brain
• It is the 14th most common cancer worldwide, affecting more males and those residing in high-income countries
• There are different types of kidney cancers according to how they appear and behave: renal cell carcinoma, transitional cell carcinoma, renal sarcoma, and Wilms’ tumour
• The exact cause of kidney cancer is not known, but risk factors include smoking, obesity, high blood pressure, long-term dialysis, exposure to certain chemicals, and hereditary conditions like von Hippel-Lindau syndrome
• Symptoms typically appear in late stages, which include passage of blood with urine, flank pain and fullness, fever, weight loss, and high blood pressure
• Diagnosis of kidney cancers IS through urine analysis, blood tests, imaging studies like an ultrasound scan of the abdomen, CT scan, and sometimes with the use of a kidney biopsy 
• Treatment of kidney cancers depends on the size of the growth and the spread and includes surgical removal, radiotherapy, immunotherapy, and targeted therapy
• Although it is difficult to prevent kidney cancers from occurring, quitting smoking, maintaining a healthy weight, and consuming a healthy diet can reduce the risk
• Survival rates are better with early detection. Around 75% of individuals survive for five years, but the prognosis is generally worse with later stages of cancer
• Offering emotional support, helping with daily tasks, and connecting patients to support groups can be vital for those with kidney cancer