Kidney Cancer Diagnosis
Diagnosed with Kidney Cancer?
We understand the anxiety that a diagnosis of kidney cancer can bring to the patient and their family. The most important thing one can do is to learn about this disease and enlist the help of an experienced team of physicians.
Most are discovered incidentally or accidentally but some are more aggressive and found after symptoms such as blood in the urine. 1/3 of kidney cancers are diagnosed after the disease has spread to other organs.
The first step is to obtain a "staging" evaluation to determine the extent of cancer. This typically entails obtaining imaging of the chest, abdomen, and pelvis and comprehensive blood work. Bone scans and evaluations of the brain are obtained depending on symptoms and the results of the initial studies. The presumed diagnosis of kidney cancer is made from radiographs (CT or MRI) and biopsy is not always performed.
PET scans are rarely obtained due to their lack of sensitivity for detecting kidney cancer.
Kidney Tumor Contained within the Kidney
"Small" Kidney Tumor (<4cm)
Increasingly, we are detecting these "small" kidney tumors due to the increased use of ultrasound, CT scan, and MRI. Typically these are detected incidentally - in other words the patient has a scan for an unrelated problem and a tumor in the kidney is found.
Not all growths on the kidney are cancer!
It is important not to confuse a potential kidney cancer with a kidney cyst or other benign lesion.
Cysts are fluid filled structures that range from being "simple cysts" which are benign to more complex cysts which could be cancerous. Cysts are graded on a scale from 1 to 4 (Bosniak Classification).
Bosniak 1 and 2 lesions are likely to be benign whereas Bosniak 3 and 4 lesions are more likely to be cancerous.
What makes a growth on the kidney suspicious is when it appears to be solid on the imaging and when it "picks up" the dye that is used during CT or MRI scans (we call this enhancement). Thus, it is important to have a good quality CT or MRI with intravenous contrast and have it read by a radiologist and urologist who are experts on kidney tumors.
High quality "kidney mass protocol" CT scan showing a right kidney tumor.The intensity of the tumor is measured in different phases. An increase of the Hounsfield Units (HU) of more than 20HU indicates that the mass is suspicious for cancer. When the dye was given, this tumor went from 33HU to 85HU. This patient underwent a robotic-assisted partial nephrectomy and the tumor was found to be a clear-cell kidney cancer.
About 20-30% of "suspicious" kidney tumors when removed prove to be benign.
These benign growths include cysts, oncocytomas, angiomyolipomas, and mixed epithelial stromal tumors. Thus, 70-80% of these "small" kidney tumors are cancers and fortunately the majority are "well behaved" (low grade) cancers. However, our studies reveal that about 1/3 of the cancers are aggressive. Thus we take these tumors very seriously.
What is an angiomyolipoma?
Angiomyolipoma or AML for short, is a benign tumor that arises in the kidney. AMLs can bleed and while not cancerous are still taken very seriously. "Angio" indicates blood vessels, "myo" indicates muscle, and "lipoma" indicates fat. Thus, an AML is a tumor that contains these 3 components. If one sees fat within the tumor on imaging, it is virtually diagnostic of this entity and biopsy to confirm the diagnosis is not necessary. Since they are benign, small AMLs can be observed in most patients. However, if they are >4cm in size they are usually treated due to the high risk of spontaneous rupture and bleeding. Treatment, when necessary, usually involves selective embolization. Embolization is a procedure where the blood vessels feeding the AML are blocked without surgery. This procedure shrinks the tumor and eliminates thus minimizing the risk of bleeding. Rarely surgery or ablation are necessary to remove the benign tumors. All AML need to be followed and monitored for size. Even if they are small, initially, they can grow to a size (>4 cm) where intervention would be necessary.
"Who gets AMLS?" AMLs are most common in females between the ages of 40-60. Additionally, about 50% of patients with a syndrome called Tuberous Sclerosis will have AMLs. Tuberous Sclerosis is a genetic disease associated with seizures, intellectual disability and a skin condition called adenoma sebaceum.
A right kidney tumor with fat consistent with an angiomyolipoma, successfully treated with selective embolization. Note how there is no blood flow to it after embolization.
Should I get a biopsy?
A question that we hear all the time. There is a theoretical risk of bleeding or spreading the cancer with a biopsy, but this not why they are not widely used.
Unlike prostate, breast or colon biopsies it turns out that biopsies of small kidney tumors are not as accurate as we would like.
As many as 20% of the biopsies are "false negatives." In other words the biopsy says there is no cancer when indeed there is a cancer.
We still use them sometimes, but it has to be in the right patient. They are especially useful when we suspect that another cancer has spread to the kidney. Recent innovations in how we do the biopsies has allowed us to get more information than ever before. It remains, however, that a biopsy should only be obtained after a discussion with an expert on this disease.
Treatment options for patients with a small kidney tumor including active surveillance, ablation, partial nephrectomy and total nephrectomy. In the vast majority of patients treatment of a small kidney tumor should result in saving the kidney. A quick decision to remove the kidney may not be the best treatment. Experience is critical in being able to save the kidney.
These are CT scans for two people found to have a left kidney tumor. The patient on the left has a poorly defined mass (radiologists typically describe it as infiltrative) while the one has the right has a well defined solid tumor. The tumor on the left was biopsied and found to be lymphoma. The patient was treated with chemotherapy and did not need surgery. The patient on the right had a robotic-assisted partial nephrectomy and was found to have a clear cell kidney cancer.)
Larger Kidney Tumors (>4cm)
As the tumor size increases, the likelihood of cancer increases as well. Large oncocytomas, which are benign, are sometime impossible to distinguish from kidney cancer and thus there is still hope that a large kidney tumor is benign. Prompt attention to these tumors is a must and a detailed evaluation is critical to making the best decision.
Questions to ask are:
- Is there any evidence of spread?
- Do the lymph nodes look enlarged?
- Is the kidney vein clear of the tumor?
- Is the adrenal gland involved?
A biopsy may be in order if the tumor looks atypical as there are rare mimickers of kidney cancer that would be treated differently.
Three such scenarios are:
- Lymphomas where the treatment would be chemotherapy and not surgery
- Infections (abscess) where the treatment would be antibiotics and drainage
- Sarcoma where the treatment entails more than just surgical removal
Treatment options for these tumors include active surveillance, partial nephrectomy and total nephrectomy. Ablation is less attractive for larger tumors.
Kidney Tumor with Suspicion of Spread
You may have been told that the kidney cancer has spread. This could be to lymph nodes, the lungs, liver, bone or even the vena cava — the largest vein in your body.
About 1/3 of patients find that the cancer has spread even without any symptoms.
For those with symptoms, you may have experienced abdominal or back pain, blood in the urine, bone pain, seizures or even bad headaches. After a full evaluation of the extent of spread a treatment plan should be formulated.
This can get quite complicated and a multidisciplinary team who specialize in kidney cancer would be best to help with this. It is important that a urologist and medical oncologist collaborate in constructing an optimal plan for your care. This multidisciplinary approach is most important for cancers with a high suspicion of spread. This is because today there are numerous options and combinations for patients with metastatic kidney cancer.
These options can include:
- Surgery - In certain settings, removal of the kidney even when the cancer has already spread has been shown to improve survival. This can often be done laparoscopically so the patient can recover rapidly and promptly receive additional therapy. Studies help define scenarios where surgical removal of the tumor may be beneficial even if the tumor has already spread.
- Targeted therapies - These are more recent therapies that target biological pathways to help fight kidney cancer. Examples are sunitinib, sorafenib, temsirolimus, bevacizumab, etc.
- Clinical trials - Innovative trials with novel therapies are formulated on a regular basis. Getting care at a center of excellence will increase your chances of finding out about these options.
- Immunotherapy - IL-2 (Interleukin-2) can be a good option for some patients and can deliver excellent results for some patients. Interferon-alpha is another option. These are utilized less offer due to the development of other therapies such as targeted therapies, which are less toxic.
There has never been a time when the options for metastatic kidney cancer were so numerous. This can be confusing and requires a coordinated effort between you and your physicians to determine the best course of action.
