Chad Tang, MD: Considerations for SBRT in metastatic RCC

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Key Takeaways

SBRT shows promise in achieving progression-free survival in metastatic RCC without systemic therapy, despite limited high-level data.
The absence of phase 3 trials leaves a gap in comparing SBRT strategies for oligometastatic and oligo-progressive RCC.
RCC's genetic heterogeneity can lead to varied treatment responses, with SBRT offering control over site-specific progression.
Clinicians should communicate the limited evidence supporting SBRT to patients, emphasizing its modest side effect profile.

In an interview with Urology Times during the American Society for Radiation Oncology (ASTRO) 2024 Annual Meeting in Washington DC, this month, Chad Tang, MD, of the department of GU Radiation Oncology at the MD Anderson Cancer Center, discussed the utility of stereotactic body radiation therapy (SBRT) in the treatment of patients with metastatic renal cell carcinoma (RCC).

As Tang noted in his ASTRO 2024 presentation topic, SBRT has been linked to significantly high rates of patients achieving progression-free survival, even without systemic therapy, for kidney cancer over about the span of a year now—though more research needs to inform the promising early evidence.

“There’s no high-level data, there’s no phase 3 randomized trials comparing these different strategies for both oligometastatic and oligo-progressive (RCC),” Tang said. “Another area I would want to highlight is that there’s a big gap in treating the primary in patients with metastatic disease.”

Regardless, SBRT’s position as an option to spare use of systemic therapy or possibly even change patients’ natural history is not being undone by any more recent study findings.

“And as we all know, (RCC) can be quite indolent sometimes,” Tang said. “We know it can be quite heterogeneous sometimes in terms of its genetic makeup, and sometimes one site just has a different evolution and it progresses while on IO/IO and IO/TKIO, and we can control that.”

Regarding the clinician-patient discussion around SBRT to treat metastatic RCC, Tang recommended his colleagues practice frankness around the level of available data supporting the treatment strategy—especially based on the patient’s age.

“In my experience, a lot of younger patients want the kitchen sink thrown at them for any possible benefit,” Tang said. “You have to be frank about, 'We can do this, but the level of evidence is thus, and not robust usually.' But usually, we also say that a lot of these techniques that we've done, the side effect profile is relatively modest.”