New Drug Slows Kidney Cancer Spread

New Drug Slows Kidney Cancer Spread

For a patient already battling kidney cancer, there are few things worse than learning the disease has spread. Now a promising drug offers new hope. What is it and how does it work?

For a patient already battling cancer, there are few things worse than learning the disease has spread. When it reaches the brain, patients often have limited options even as their chance for survival plummets. For some, even radiation and surgery are unavailable because parts of the brain remain inaccessible. Now a promising drug offers new hope. What is it and how does it work?


Your Kidneys and Cancer


The size of your fist and the shape of a bean, your kidneys rest on either side of your spine. These organs are your body’s filtration system. Besides removing waste and reducing water and salt in our blood, kidneys also regulate our supply of red blood cells and control our blood pressure. Chances are you pay little attention to them–––until something goes wrong. Because early stage kidney disease has few symptoms, it’s often undiagnosed. Millions of people are at risk. Nearly 40 million Americans have chronic kidney disease.


People with advanced kidney disease also have an elevated cancer risk. As a result of genetic mutations, cancer cells can spread––or metastasize beyond the original organ. In the case of kidney cancer, these cells can travel through the bloodstream or the lymph nodes, reaching the bones, lungs, testicles, liver, or the ovaries. Most frightening, like chronic kidney disease, early stage kidney cancer is usually asymptomatic. That means it can spread before being detected. In as many as 10 percent of patients with kidney cancer, the disease eventually spreads to the brain. When this happens, the chance of survival plummets. Recent research overseen by the Dana-Farber Cancer Institute’s Lank Center for Genitourinary Oncology in Boston, Massachusetts, reveals a promising treatment that might improve those odds. 


The Treatment


Along with melanoma and cancers of the breast and colon, kidney cancer is the most likely to spread to other organs. Patients should be on the lookout for headaches, sometimes accompanied by an upset stomach, memory issues, or seizures as these are symptoms that the cancer has metastasized and reached the brain. Although the five-year survival rate for patients with kidney cancer is 93%, that number plunges to 13% if the disease spreads.


Yet patients with metastatic kidney cancer that had reached the brain were often excluded from clinical trials. The rewards are too low, the risks too high. Plus many drugs that work outside the brain don’t work within it, partly due to the blood-brain barrier. Researchers refused to ignore the potential benefits of a drug they’d already noticed was effective at reducing cancer spread or the size of tumors. Plus, the drug, cabozantinib, had already been approved to treat advanced renal cell (kidney) cancer. It is able to penetrate the blood-brain barrier. For the study, nearly 90 people with metastatic kidney cancer that had reached the brain were recruited. 


Cabozantinib works by attacking several different areas in the cancer cells. A tyrosine kinase inhibitor, the drug is considered a targeted therapy that blocks the action of enzymes to keep them from growing. Nearly 90 patients were recruited for a retrospective cohort study from four countries––Belgium, France, Spain, and the U.S. Conducted from January 2014 through October 2020, it divided patients into two groups: one that had brain-directed local therapy and the other without such treatment. Whether or not patients received radiation or surgery, they showed significant improvement along with a median survival of 15-16 months. 


While not a cure, this drug offers a new potential treatment. As the study’s senior author and director of the Lank Center, Toni Choueiri, MD, explained, after the treatment “we measured the dimension of the metastases in the brain and saw a response rate that was higher than what we usually expect, and there were some nice examples of metastases really shrinking.” Although some tumors became drug resistant, others continued to shrink. The treatment also appears to work for other areas affected by the cancer’s spread. Currently a phase II trial of cabozantinib is going on in France.