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 occurs mainly in people with cystic kidney disease (ACKD).
ACKD usually occurs in patients with advanced chronic kidney disease who have been on dialysis for a long time. Nearly 60 percent of people develop ACKD within 2 to 4 years of starting dialysis, the process of removing waste and fluids from the body that the kidneys are supposed to do.
It is known that having ACKD significantly increases the risk of kidney cancer. An estimated 1.6%–8% of ACKD patients are diagnosed with cystic renal cell carcinoma each year. Overall, approximately 19% of patients with ACKD have renal cell carcinoma (all types).
Fortunately, many cystic renal cell carcinoma tumors grow relatively slowly and often respond well to treatment.
This article will review currently known symptoms, causes, and risk factors, the diagnostic process and treatment options, and coping strategies.
Symptoms of Cystic Renal Cell Carcinoma
Also known as acquired cystic disease-associated renal cell carcinoma (ACD-RCC), cystic renal cell carcinoma is most often diagnosed when it is asymptomatic (causing no symptoms). Most cases are discovered during routine imaging scans or screening for chronic kidney disease.
When symptoms occur, they may include:
- Hematuria (blood in the urine): Blood may be visible (gross hematuria) or only visible under the microscope (microscopic hematuria). Microscopic hematuria is by far the most common.
- Kidney pain: Pain in your side (flank) and back that may feel like being kicked or bumped.
- Abdominal mass: This may be noticed in some cases, but these tumors are usually diagnosed long before they are 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 is thought that chronic kidney disease may alter the tissue surrounding the area in a way that initiates the process of cancer formation (tumorigenesis).The process usually starts off well forward Dialysis is required.
After the onset of cancer, Uremia (The accumulation of urea and other waste products that are not adequately removed or filtered from the blood due to kidney disease) promotes tumor formation. Oxidative stress (accumulation of tissue-damaging molecules) associated with dialysis may also contribute to the continued survival and growth of tumors.
When talking about risk factors for cystic renal cell carcinoma (CKD-RCC), there are two levels. There are risk factors for cancer development, and then risk factors for chronic kidney disease, which ultimately leads to cancer.
Risk factors for CKD-RCC include:
- end-stage chronic kidney disease
- Dialysis: The longer a person is on dialysis, the more likely they are to develop acquired cystic disease and the greater the chance of developing cancer. People on long-term dialysis (eg, more than 10 years) are at the highest risk.
- Men: Kidney cancer is more common in men than women.
ACD-RCC has been diagnosed in a small number of people who have not yet started dialysis. While a person’s risk of developing ACD-RCC increases the longer a person is on dialysis, the researchers don’t believe dialysis itself is the cause. Instead, it is believed that kidney disease (the cause of dialysis) ultimately leads to DNA changes that lead to cancer.
The prevalence of renal cell carcinoma is low (5%) in people who have undergone a kidney transplant, which is thought to reduce the chance of developing cancer.
The most important risk factors for chronic kidney disease are diabetes, hypertension and glomerulus nephritis (inflammation of the tiny filters in the kidneys).
The diagnosis of ACD-RCC begins with knowing the risk factors and having a healthcare provider with a high degree of suspicion for the disease. Because of underlying kidney disease, many people will have regular scans for diagnosis. There are no laboratory tests that can help make a diagnosis.
Imaging tests that can 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 method of choice for diagnosing renal cell carcinoma.
- Magnetic Resonance Imaging (MRI): MRI uses strong magnets to create 3-dimensional images of the body. In some cases, MRI may help to further identify problem areas seen on CT.
- Ultrasound: Ultrasound uses sound waves to create images of the inside of the body. It is especially helpful in evaluating cysts.
Although CT or ultrasound may point to the tumor, imaging alone cannot make a diagnosis. Not only are these tumors difficult to distinguish from other cancers in the kidney, but they are also difficult to distinguish from benign (noncancerous) tumors.
Biopsy and Pathology
To make an accurate diagnosis, a biopsy is required to obtain a tissue sample from the nodule. Biopsy can be done in a variety of ways, but needle biopsy is the most common.
In this procedure, a thin needle is inserted through the skin into the lump in the kidney. The sample is then removed for evaluation by a pathologist (a doctor who specializes in diagnosing the disease).
Microscopically, these tumors can resemble papillary renal cell carcinoma, so further workup is usually necessary to make an accurate diagnosis.
The standard treatment for cystic renal cell carcinoma (ACD-RCC) is surgery, which is curable if the tumor is caught early. The choice of surgery depends on the size and location of the tumor, including:
- part of Nephrectomy: For very small tumors, this procedure involves removing the cancer and a small amount of surrounding tissue.
- Simple nephrectomy: This procedure involves removing the entire kidney. Simple nephrectomy is usually performed for stage 1 cancer, but radical surgery can also be performed.
- Radical nephrectomy: Radical nephrectomy involves removing the entire kidney as well as the adrenal gland, nearby lymph nodes, and some surrounding tissue such as fat and Fascia.
Apart from surgery, there are limited effective options for treating tumors. Chemotherapy is considered ineffective. Targeted therapy was used more frequently, but one report with the drug Sutent (sunitinib) documented no response.
In general, cystic renal cell carcinoma (ACD-RCC) is considered to have a better prognosis than other types of renal cell carcinoma for a number of reasons. Some of these include:
- Aggressive: On average, these tumors tend to be less aggressive (slower growing).
- Early diagnosis: Many people at risk of developing these tumors are regularly monitored.
- Age: These tumors are usually diagnosed at a younger age
In one study, people who were followed up for 4 years of ACD-RCC had no evidence of tumor recurrence or spread (metastasis).
Dealing with any type of cancer is challenging, and cystic renal cell carcinoma (ACD-RCC) is no exception. It doesn’t matter whether it’s a small, easily curable tumor or a large, more advanced tumor, facing cancer is scary.
While the prognosis for this type of cancer is relatively good, the fact that you’ve been diagnosed can mean you’ve already had to deal with chronic kidney disease, dialysis, and more. Some people find that facing another diagnosis can be frustrating and overwhelming.
People can successfully cope with cancer in a number of ways. These include:
- Understanding Disease: Knowledge can be powerful when faced with cancer. Knowing how your tumor was diagnosed and treated, and any follow-up needed, can put you in control.
- Seek support: Support from family and friends is critical. Some people find it difficult to seek help if they have had a medical problem for a while. It’s hard to ask, no one wants to be a burden, but most want to help. In fact, family and friends of cancer patients often say the worst feeling is helplessness. Seeking support can benefit not only you, but your loved ones as well.
- Practice Self-Care: Find a way to pamper yourself. This can feel forced and contrived at first, and you may have to consciously give yourself permission. If you find this difficult, consider what you would do to brighten the day of a loved one facing a new cancer diagnosis and apply this care to yourself.
Coping, Support and Living with Chronic Kidney Disease
Cystic renal cell carcinoma is a subtype of kidney cancer. It is most common in people with acquired cystic kidney disease who are on dialysis. This cancer is usually found during routine imaging scans or screening for kidney disease. A biopsy is required to accurately diagnose the tumor subtype. Surgery is the treatment of choice, and if cancer is detected early, it is often considered curable.
If you or a loved one is diagnosed with cystic renal cell carcinoma (ACD-RCC), your first feeling may be discouragement. Coping with kidney disease takes a lot of effort, all of which lead to a diagnosis and dialysis, just to face another diagnosis.
Despite the relatively good prognosis for these tumors, let yourself be sad. Find a good friend and vent. Yes, a positive attitude can help. But don’t store those negative emotions. Once you express your feelings, it may bring some relief because no one should face what you have and then also cancer. It may also give you new resolutions.