December 2023 | George M. Pikler, M.D., Ph.D., FACP
The most common form of kidney cancer is called renal cell carcinoma. In most people the disease is a single localized tumor, ranging in size from less than 4 centimeters (about 1.5 inches wide) and up to about 10 centimeters (about 4 inches wide).
Surgery is the most common treatment for localized kidney cancer. Surgery can cure the disease in many patients. For smaller tumors, depending on factors such as their location, surgery typically involves removing only the part of the kidney that includes the tumor – a partial nephrectomy. Otherwise, the entire kidney is removed – a radical nephrectomy.
But a small percentage of people diagnosed with localized kidney cancer can’t have surgery. Most often that’s because they have other health conditions—such as obesity, heart disease, or chronic kidney disease—that make surgery dangerous or not feasible. Starting in the early 2000s, stereotactic body radiotherapy (SBRT) emerged as a possible alternative for this group of people.
The technique requires patients to undergo several imaging procedures that allow doctors to precisely map the tumor in the kidney. Based on that mapping, radiation oncologists then develop a treatment plan that allows them to target multiple radiation beams directly to the tumor. The entire procedure is noninvasive.
A clinical trial called FASTRACK II, conducted by Dr. Shankar Siva at the Peter MacCallum Cancer Centre in Melbourne, Australia, included 70 patients with a single tumor in their kidney, measuring 7 centimeters or less, who were not able to undergo surgery, mostly because of other comorbidities. All these patients had their tumors treated with SBRT, and over the next few years only one patient had a recurrence with metastatic disease 3 years after receiving the treatment.
SBRT also appeared to be safe—in particular, it had no notable impact on patients’ kidney function, according to results reported on October 1, 2023, at the American Society for Radiation Oncology (ASTRO) annual meeting.
A clinical trial comparing SBRT against surgery is being considered at this time.