Finding out that you have kidney cancer can bring up many questions and concerns. To understand how serious your cancer is, your healthcare team will perform tests to determine the grade (how abnormal the cancer cells look) of your tumor.

Cancer grades describe how aggressive (how quickly the cancer is likely to grow and spread) the cancer cells appear under a microscope. This helps healthcare providers recommend the most effective treatment plan and helps people with kidney cancer better understand what to expect.

If you or a loved one has been diagnosed with kidney cancer, learning more about the grading process can help you feel more informed and prepared for conversations with your doctor.

In this article, we’ll explain the different grades of kidney cancer, highlight the prognosis (outlook) for each grade, and discuss how grades may influence treatment options.

How Is Kidney Cancer Graded?

Once you receive a kidney cancer diagnosis, your healthcare team will assign your cancer a grade from 1 to 4.

This is different from a cancer stage. Cancer stages describe the size of a tumor and how far it has spread. Like cancer grades, stages are assigned a number from 1 to 4 (though often written with Roman numerals, such as stage III for stage 3). This can be confusing for many people.

To grade kidney cancer, healthcare providers take a sample of the tumor cells from a biopsy or surgery. A pathologist (a doctor who studies cells and tissues to diagnose disease) examines the cells under a microscope to determine how abnormal they look.

In general, the more abnormal the cells appear, the higher the grade and the more aggressive the cancer may be.

Grading Systems

The grade of your kidney cancer is listed in your pathology report. This report explains the pathologist’s findings about your tumor (including how the cancer cells look under a microscope). Currently, pathologists use a grading system provided by the International Society of Urological Pathology (ISUP).

In your pathology report, you may see this grading system called the WHO/ISUP grading system. (WHO stands for the World Health Organization.) In the past, pathologists used the Fuhrman grading system, but they switched to the WHO/ISUP system following its formal adoption in the 2016 WHO Classification of Tumours of the Urinary System.

If you were initially diagnosed before 2016, your original report may use this older grading system.

What Do Kidney Cancer Grades Mean?

Kidney cancer grades can help determine how aggressive the cancer is. In general, a lower grade means that the cancer cells appear more similar to healthy cells.

Grades 1 and 2 cancers usually grow slowly and are less likely to spread to distant areas of the body.

A higher grade means that the cancer cells are very different from healthy kidney cells. Cancers with a grade of 3 or 4 usually grow quickly and may be more aggressive.

When grading kidney cancer cells, pathologists look at each cell’s nucleus (the part of the cell that contains DNA, or genetic material). A cell’s nucleus is its control center. It’s located in the middle of the cell and contains the cell’s genetic information.

When the cancer cell’s nucleus looks like a normal cell, it will likely have a lower grade. Cancers with lower grades are usually less aggressive and tend to grow more slowly.

Grade and Prognosis

Higher-grade cancer cells appear very different from normal cells. They tend to grow quickly and are more likely to spread to other areas of the body.

Your healthcare team will consider your cancer’s grade when determining your prognosis. A prognosis is an estimate of how your cancer will progress and respond to treatment.

While the cancer’s grade can help determine the prognosis, the most important factor is the cancer’s stage (how large the tumor is and how far it has spread).

Both your cancer grade and stage will be listed on your pathology report. If your report includes two grades, your healthcare team will use the higher grade when determining your prognosis and treatment plan.

Grade 1 Kidney Cancer

Grade 1 is the lowest cancer grade, and it describes cancer cells that look very similar to normal, healthy cells. Grade 1 kidney cancer has the best prognosis because these cancer cells tend to grow slowly and are less aggressive than other grades.

Grade 1 is the least common grade diagnosed, and about 10 percent of people with kidney cancer have grade 1 tumors.

When determining an effective treatment plan, your healthcare team will consider your cancer’s grade, stage, and other factors. Small cancers that don’t appear to be growing or spreading may not require medical treatment right away.

Active surveillance (closely monitoring the tumor with regular checkups and imaging tests) involves monitoring your tumor and overall health before beginning treatment. This approach may be recommended for people with small, slow-growing or less aggressive tumors.

Grade 2 Kidney Cancer

Grade 2 is the most common grade seen in kidney cancer. Grade 2 cancer cells look less normal than grade 1 cells and tend to be more aggressive. About half of people with kidney cancer have grade 2 tumors.

Grade 2 cancer cells usually have an abnormal-looking nucleus. In grade 2 tumors, a small structure inside the nucleus called the nucleolus (a part of the cell that helps make proteins) becomes visible under the microscope at high magnification.

Treatment for grade 2 kidney cancer depends on the stage and how quickly the tumor seems to be growing and spreading. Your healthcare team may recommend surgery to remove part or all of the kidney. If the tumor is small and low-grade, you may not require any additional treatment after surgery.

Grade 3 Kidney Cancer

Grade 3 cancer cells are more abnormal than grades 1 and 2. They tend to grow quickly and may be more likely to spread. About 25 percent of people with kidney cancer are diagnosed with grade 3 tumors.

High-grade cancers usually require more treatment after surgery to make sure that the cancer doesn’t come back, which is known as recurrence.

Your healthcare team may recommend immunotherapy, which boosts your body’s immune response to the cancer cells. Immunotherapy medications help the immune system recognize and destroy cancer cells.

For high-grade kidney cancer, the immunotherapy drug pembrolizumab (Keytruda) may be recommended in some cases, depending on your individual situation.

Grade 4 Kidney Cancer

Grade 4 cancer cells are very abnormal-looking. Their nuclei appear large and more visible under a microscope. About 15 percent to 20 percent of people with kidney cancer have grade 4 tumors. This is the most aggressive grade.

In addition to nucleus changes, cancer cells sometimes have certain characteristics that help pathologists determine the grade. Kidney cancer cells with sarcomatoid or rhabdoid features are automatically classified as grade 4 because they’re known to be very aggressive.

If you see the term “sarcomatoid dedifferentiation” on your pathology report, it means that your cancer cells have a “spindle” shape (long and narrow) or another stretched-out shape.

If you see the term “rhabdoid dedifferentiation,” it means that your cancer cells have a rod or rounded shape.

Cancer cells with these features tend to grow and spread quickly.

Having cancer cells with sarcomatoid or rhabdoid features can happen in any subtype of kidney cancer. It’s possible to have one, both, or neither of these characteristics.

No Grade

There are several types and subtypes of kidney cancer, with renal cell carcinoma (RCC) being the most common.

Clear cell tumors and papillary tumors can be graded using the WHO/ISUP grading system.

However, there is currently no way to grade chromophobe renal cell cancer. If you’ve been diagnosed with chromophobe renal cell carcinoma (a less common subtype of kidney cancer), you won’t see a grade on your pathology report.

Find Your Team

On MyKidneyCancerTeam, people share their experiences with kidney cancer, get advice, and find support from others who understand.

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