What is the cancer control rate of stereotactic body radiation therapy (SBRT) in renal cell carcinoma (RCC)?

From the Guidelines

Stereotactic body radiation therapy (SBRT) for renal cell carcinoma (RCC) achieves a local cancer control rate of approximately 90% at 1 year, as evidenced by a systematic review of 28 studies including 1,602 patients with RCC oligometastases [@8@].

Key Factors Influencing Treatment Efficacy

• Tumor size: smaller tumors generally respond better to SBRT
• Location: control rates vary by site, with lung, bone, and brain metastases having different response rates
• Total radiation dose: ablative doses are necessary to overcome radioresistance mechanisms in RCC cells
• Fractionation schedule: 3-5 fractions are commonly used to deliver doses of 30-60 Gy
• Patient performance status: patients with good ambulatory status and low burden of metastatic disease tend to have better outcomes

Treatment Considerations

• SBRT is a valuable option for patients who are poor surgical candidates or have oligometastatic disease
• Side effects are typically minimal and location-dependent, with most patients tolerating the treatment well
• The use of SBRT in RCC is supported by recent guidelines, including the ESMO clinical practice guideline for diagnosis, treatment, and follow-up of renal cell carcinoma 1

Evidence Summary

• A systematic review of 28 studies found that stereotactic radiotherapy is safe and efficacious for RCC oligometastases, with 1-year local control at 90% and any significant toxicity at 1% [@8@]
• The ESMO guideline recommends the use of SBRT in the management of brain metastasis, instead of whole-brain RT, due to its effectiveness and lower risk of cognitive dysfunction 1

From the Research

Cancer Control Rate of Stereotactic Body Radiation Therapy (SBRT) in Renal Cell Carcinoma (RCC)

• The local control rate of SBRT in RCC is estimated to be around 95-99% at one year, 96-98% at two years, and 94-96% at five years 2, 3.
• A meta-analysis of 22 studies found that the local control rate was 99% (95% CI: 97-100%) at one year, 98% (95% CI: 96-99%) at two years, and 94% (95% CI: 90-97%) at five years 2.
• A large multicenter series of 144 patients with primary RCC treated with SBRT reported a local control probability of 98% at one year (95% CI, 94-99) and 96% at five years (95% CI, 92-99) 3.
• Another study found that the local control rates at 6,12, and 24 months were 87.5%, 82.9%, and 77.6%, respectively, in patients with metastatic RCC treated with SBRT 4.
• A review of radiation therapy options in kidney cancer reported that local control is estimated at >95% for primary RCC treated with SBRT, and grade 3-4 toxicity is limited at ≤5% 5.

Factors Affecting Cancer Control Rate

• The biologically equivalent dose (BED) of SBRT does not seem to have a significant impact on local control, progression-free survival, and overall survival in patients with RCC 2.
• The treatment regimen, including the dose and fractionation schedule, may affect the local control rate and toxicity profile of SBRT in RCC 2, 3.
• The tumor size, location, and patient's overall health may also impact the effectiveness of SBRT in controlling RCC 3, 4.

Toxicity Profile

• The toxicity profile of SBRT in RCC is generally acceptable, with grade 3-4 toxicity limited at ≤5% for primary RCC and ~1% for metastatic RCC 2, 5.
• The most common toxicities reported include fatigue, nausea, and vomiting, as well as renal function decline 3, 4.
• The incidence of severe toxicities, such as grade 4 toxicity, is rare, with only 1% of patients experiencing dialysis after SBRT 3.