What Is Cystic Renal Cell Carcinoma?

Cystic renal cell carcinoma is a relatively new subtype of kidney cancer, first described in 2005, and recognized as a distinct tumor in 2013. It primarily occurs in people who have acquired cystic kidney disease (ACKD).

ACKD usually develops in people with advanced chronic kidney disease who have been on dialysis for a significant period of time. Nearly 60% of people develop ACKD within 2 to 4 years of beginning dialysis, a procedure that removes waste products and fluids from your body, the way your kidneys should.

Having ACKD is known to significantly raise the risk of developing kidney cancer. It is estimated that 1.6%–8% of people with ACKD are diagnosed with cystic renal cell carcinoma each year. And approximately 19% of people with ACKD overall are living with renal cell carcinoma (all types).

Fortunately, many cystic renal cell carcinoma tumors are relatively slow growing and generally respond well to treatment.

This article will review what is currently known about the symptoms, causes and risk factors, diagnostic process, and treatment options, as well as strategies for coping.

Symptoms of Cystic Renal Cell Carcinoma

Also called acquired cystic disease-associated renal cell carcinoma (ACD-RCC), cystic renal cell carcinoma is most often diagnosed when it is asymptomatic (not causing any symptoms). Most cases are discovered during routine imaging scans or screening for chronic kidney disease.

When symptoms are present, they may include:

• Hematuria (blood in the urine): Blood may be visible (gross hematuria) or only seen under a microscope (microscopic hematuria). Microscopic hematuria is by far most common.
• Kidney pain: Pain along your side (flank) and back, which can feel achy, like being kicked or bumped.
• Abdominal mass: This may be noted in some cases, but these tumors are usually diagnosed long before they can be felt.

Causes and Risk Factors

Like most cancers, researchers believe that the development of cystic renal cell carcinoma begins with mutations (changes) in the DNA of normal kidney cells that cause the cells to grow out of control.

It's thought that chronic kidney disease may alter the tissue surrounding the area in some way, which starts the process of cancer formation (oncogenesis). This process usually begins well before dialysis is needed.

After a cancer is initiated, uremia (the buildup of urea and other waste products that are not adequately removed or filtered from the blood because of the kidney disease) promotes the formation of a tumor. Oxidative stress (buildup of tissue-damaging molecules) associated with dialysis may also help facilitate the continued survival and growth of the tumor.

Risk Factors

In talking about risk factors for cystic renal cell carcinoma (CKD-RCC), there are two levels. There are the risk factors for development of the cancer, and then the risk factors for chronic kidney disease that ultimately leads to the cancer.

Risk factors for CKD-RCC include:

• Advanced chronic kidney disease
• Dialysis: The longer a person is on dialysis, the more likely that acquired cystic disease will develop, and the greater the chance of cancer occurring. People who have received long-term dialysis, for example, longer than 10 years, carry the highest risk.
• Male sex: Kidney cancer is more common in men than women.

ACD-RCC has been diagnosed in a few people who have not yet started dialysis. While the risk of ACD-RCC increases the longer a person is on dialysis, researchers do not believe that dialysis itself is the cause. Rather, it's thought that the kidney disease (the cause for dialysis) is ultimately responsible for the DNA changes leading to cancer.

The prevalence of renal cell carcinoma is lower in those who have had a kidney transplant (5%), and it's thought that kidney transplants reduce the chance of developing the cancer.

The most important risk factors for chronic kidney disease are diabetes, high blood pressure, and glomerulonephritis (inflammation of the tiny filters in the kidneys).

Diagnosis

The diagnosis of ACD-RCC begins with being aware of the risk factors and having a healthcare provider who highly suspects the disease. Due to the underlying kidney disease, many people will be having scans done periodically that lead to the diagnosis. There are no lab tests that help in making the diagnosis.

Imaging

Imaging tests that may be used to evaluate the kidneys include:

• Computed tomography (CT): CT uses a series of X-ray images to create a 3-dimensional image of the body. It is considered the preferred method for diagnosing renal cell carcinoma.
• Magnetic resonance imaging (MRI): MRI uses strong magnets to create a 3-dimensional image of the body. In some cases, an MRI may help further define areas of question seen on a CT.
• Ultrasound: Ultrasound uses sound waves to create images of the inside of the body. It is particularly helpful in evaluating cysts.

While a CT or ultrasound may point to a tumor, imaging alone cannot make the diagnosis. These tumors can be very difficult to distinguish not only from other cancers in the kidneys but benign (noncancerous) tumors, as well.

Biopsy and Pathology

A biopsy to obtain a sample of tissue from the nodule is needed to make an accurate diagnosis. A biopsy may be done in a number of ways, but a needle biopsy is used most often.

In this procedure, a long, thin needle is inserted through the skin and into the mass in the kidney. A sample is then removed to be evaluated by a pathologist (a doctor specializing in disease diagnosis).

Under the microscope, these tumors can resemble papillary renal cell carcinoma, so further testing is often needed to make an accurate diagnosis.

Treatment

The standard treatment for cystic renal cell carcinoma (ACD-RCC) is surgery, and this can be curative when the tumors are detected early. The choice of surgery depends on the size and location of the tumor, including:

• Partial nephrectomy: Used for very small tumors, this procedure involves removing the cancer and a small amount of surrounding tissue.
• Simple nephrectomy: This procedure involves the removal of the whole kidney. A simple nephrectomy is often done for stage 1 cancer, but a radical procedure may be done as well.
• Radical nephrectomy: A radical nephrectomy includes removal of the entire kidney as well as the adrenal glands, nearby lymph nodes, and some of the surrounding tissues such as fat and fascia.

Other than surgery, there are limited effective options for treating the tumors. Chemotherapy is thought to be ineffective. Targeted therapies are being used more often, but the one report recorded with the medication Sutent (sunitinib) showed no response.

Prognosis

In general, the prognosis of cystic renal cell carcinoma (ACD-RCC) is thought to be better than other types of renal cell carcinomas for a number of reasons. Some of these include:

• Aggressiveness: These tumors, on average, tend to be less aggressive (grow more slowly).
• Early diagnosis: Many people at risk for these tumors undergo frequent monitoring.
• Age: These tumors are usually diagnosed at a younger age

In one study, a follow-up of people who had been treated for ACD-RCC for four years found that none of the patients had a recurrence or evidence of spread (metastasis) of their tumors.

Coping

Coping with any type of cancer is challenging, and cystic renal cell carcinoma (ACD-RCC) is no different. Whether it is a small, easily curable tumor or a large, more advanced tumor doesn't really matter, facing cancer is frightening.

While this type of cancer carries a relatively good prognosis, the fact that you've been diagnosed likely means that you've already had to cope with chronic kidney disease, dialysis, and more. Some people find that facing yet another diagnosis can be discouraging and overwhelming.

There are a number of ways people cope successfully with cancer. These include:

• Learning about the disease: Knowledge can be powerful when facing cancer. Understanding how your tumor is diagnosed and treated and any follow-up that's needed can give you some control.
• Find support: Support from family and friends is crucial. Some people find it difficult to ask for help if they've already been living with medical problems for some time. It's hard to ask, and nobody wants to be a burden, but most people want to be of help. In fact, family and friends of someone facing cancer often say the worst feeling is the sense of helplessness. Asking for support may not only benefit you but your loved ones as well.
• Practice self-care: Find a way to pamper yourself. This may feel forced and artificial at first, and you may have to consciously give yourself permission. If you're finding this hard, consider what you would do to brighten the day of a loved one facing a new diagnosis of cancer and apply that care to yourself.

Summary

Cystic renal cell carcinoma is a subtype of kidney cancer. It most commonly occurs in people with acquired cystic kidney disease who have been on dialysis. This cancer is usually caught in routine imaging scans or screening for kidney disease. A biopsy is needed to accurately diagnose the tumor subtype. Surgery is the preferred treatment and is often considered curative if the cancer is caught early.

A Word From Verywell

If you or a loved one has been diagnosed with cystic renal cell carcinoma (ACD-RCC), your first feeling may be discouragement. It takes a lot out of you to cope with kidney disease, all that led up to that diagnosis, and dialysis, only to be faced with another diagnosis.

Even though these tumors carry a relatively good prognosis, let yourself grieve. Find a good friend and vent. Yes, being positive can help. But don't store up those negative feelings. Once you express your feelings, it may bring some relief in the sense that nobody should have to face all you have and then cancer, too. It may also give you newfound determination.