Pedro Barata, MD, MSc: The other piece of the story that helps us understand a little about prognosis has to do with the histology. Renal cell carcinoma [RCC] can be many things. Most commonly, we’re talking about clear cell RCC. About 3 of 4 patients we see will have renal cell carcinoma, and the rest will fall under the category of non–clear cell. We have the papillary and then even more rare, we’re talking about chromophobe, translocation, undifferentiated, collecting duct, etc. Those are difficult diseases to treat and much rarer forms of RCC. To your question, prognosis is completely dependent on histology but also dependent on the staging that patients present in clinic.

Benjamin Garmezy, MD: These are excellent points. Most of our treatments for patients with renal cell carcinoma in clinic are similar. We have immunotherapy targets, mTOR inhibition of course, and VEGF TKIs [tyrosine kinase inhibitors], but these histologies are independent diseases. In the future, hopefully we’ll have novel treatments that can change the trajectory of patients with varying histologies because we shouldn’t be treating them as a basket of patients, as we’re doing now. That’s not to say we’re doing anything incorrectly. We just need more information and more data. Hopefully, we’ll be able to figure that out as a community of GU [genitourinary] research physicians. As far as risk stratification goes, we’ve talked a bit about that, and histologies and staging at diagnosis can make a difference. Are there any other tools you’re using in clinic?

Pedro Barata, MD, MSc: That’s a great question. When you talk about risk groups and stratification, the most popular ones come to mind: IMDC [International Metastatic RCC Database Consortium Risk Model] and Memorial Sloan Kettering [Cancer Center] risk score. Those scores have been around for a while. They’ve been developed the context of the old TKI era, where sunitinib was the standard of care. Whether you use IMDC or Sloan Kettering, you can categorize those patients into favorable, intermediate, and poor risk. That’s out of a multivariate analysis [MVA]. Basically, you put hundreds of patients together, you run an MVA model, and you come up with several factors, including time from diagnosis to treatment, anemia, etc. Depending on the number of risk factors present, we’re able to categorize those patients. It’s actually prognostic because overall survival is impacted by the presence of those factors at baseline. I’d argue that today, IMDC is becoming more popular because of what we’re going to talk about next. All the I/O [immuno-oncology]–based strategies have been enrolling patients, knowing up front the risk group they belong to. A lot of data came out of that to help us understand the categories patients can be part of, to simplify our discussions about metastatic space in the front line.

Benjamin Garmezy, MD: That’s a critical point. When we think about the most common risk-stratification tools we use in clinic, from the community perspective, we sit on pathways and create algorithms in treatment guidelines for physicians who treat multiple tumor types, not just renal cell carcinoma. We know that the IMDC risk stratification tool has risen to the top. Doctors are using it in clinic to help identify the appropriate treatments for their patients. That is something we use frequently in our practice.

Pedro Barata, MD, MSc: That’s absolutely true.

Transcript edited for clarity.