Renal Cell Carcinoma - Episode 2

Classification of Renal Cell Carcinoma

An expert in urologic oncology reviews the staging, grade, and types of renal cell carcinoma.

Thomas Hutson, DO, PharmD: In the 70% of patients that initially present that are offered curative therapy, the likelihood that they will develop recurrence or metastatic disease at a later time is dependent upon what we call the Stage of the cancer. There are four stages of the cancer. Stage 1, 2 and 3 are the local, locally advanced cancers that are potentially cured. Stage 4 is the cancer that has already spread or that has recurred, that is metastatic and is not curable. The likelihood of cure for Stage 1, 2 and 3 changes based upon a variety of characteristics. One is the size of the tumor. The larger the tumor is, the higher the stage of the tumor, the less likely it will be cured. Also, we look at what’s called the grade of the tumor, which is simply how aggressive the cancer looked under the microscope to the pathologist. The more aggressive-looking tumors have less likelihood of being cured.

There are other things that are evaluated that will give some prognostic information. I don’t want to put too much emphasis on them because they can be quite technical. These are things such as the margin status, was there a positive margin or a negative margin, was there evidence of lymphovascular invasion, was there evidence of penetration of the renal capsule, was there involvement of the renal vein. Those are all kind of additional factors that will portend a worse prognosis, a less chance of cure, or a higher chance of recurrence.

Finally, there are different types of renal cell cancer. This has been one of the greatest improvements in pathology understanding of this disease and it happened about 25 years ago when it was recognized that not all renal cell cancers were the same. In fact, there were at least five main types of renal cell cancer. Thankfully, the most common type, which is called clear cell, it represents 75% to 80% of what we see. Thus, if you play Vegas odds, you're most likely to have a clear cell renal cell cancer. That is the cancer that we know the most about. That is the cancer type that has been studied in all of the clinical trials that resulted in approval of new therapies for kidney cancer. The other group we simply call non-clear cell renal cell, and those non-clear cell renal cells include papillary, of which there’s two types, as well as chromophobe, collecting duct, medullary, and unclassified. Thus, those rarer types, again represent 20%, and the frequencies of them in some instances is only 5% to 7%.

Based upon that, we unfortunately know the least about those cancers. But let’s not get too disappointed as the therapies that we have approved for clear cell have also been approved for the non-clear cell histologies and can provide benefit in those too. Thus, even though a patient may have a non-clear histology, as long as it’s renal cell cancer, we have therapies that we can utilize to help treat, extend life, control the cancer, and allow patients to have a quality of life for as long as possible.

This transcript has been edited for clarity.