Renal cancer SABR: expanding treatment options for suitable patients

Some patients with localised RCC cannot undergo surgery because of comorbidities, frailty, anaesthetic risk or technical factors such as tumour position. These patients may nevertheless have localised T1b disease for which active treatment remains appropriate.

SABR provides a non-invasive local treatment without an incision, ablation probe or general anaesthetic and is usually delivered in an outpatient setting. Although RCC was historically considered relatively resistant to conventional radiotherapy, SABR delivers much higher doses per fraction, allowing an ablative dose to be targeted precisely to the tumour.

At GenesisCare, renal SABR referrals are reviewed by the Urology SABR Advisory Team, which is responsible for reviewing referrals for urological SABR, including kidney cancer. Clinical information and imaging can be rapidly uploaded and reviewed through the eMDT, with meetings held twice weekly to provide a timely opinion on whether SABR is appropriate and which treatment approach may be most suitable.

This sits within an established national SABR service treating up to 1,000 patients each year across tumour sites. GenesisCare's SABR programme has been developed over more than a decade, with MRI-guided adaptive radiotherapy integrated into the service for complex cases. GenesisCare has also delivered MRI-guided fully adapted SABR for primary renal cancer since 2020, when its Oxford team reported what it believed to be the first treatment of its kind in the UK. To date, GenesisCare has treated 39 patients with renal cancer on an MR Linac*.

MRI-guided adaptive radiotherapy can be particularly useful for renal tumours because the kidneys move with respiration and may lie close to radiosensitive structures such as the bowel. MR Linac technology provides high-quality soft-tissue imaging during treatment, allowing the target and surrounding organs to be visualised and the treatment plan adapted to the anatomy seen on the day.

Based on our clinical experience at GenesisCare, we recommend specialist MR Linac review for more complex renal cases, including tumours >7 cm, tumours in close proximity to the bowel and tumours within a solitary kidney. In these situations, daily adaptive planning and respiratory gating can help account for changes in anatomy and tumour movement, supporting precise dose delivery while limiting exposure to nearby organs at risk and healthy renal tissue. Cases involving tumours >7 cm sit outside current NICE recommendations² for renal SABR and therefore require individual specialist assessment.

GenesisCare currently operates three MR Linacs in its centres in Oxford, London and Surrey with the addition of a fourth MR Linac at our new Leeds centre, opening in January 2027, which will further expand our UK network. Since 2019, we have developed extensive experience in consultant-led, daily adaptedablative radiotherapy through our MR Linac programme, and our Leeds service will expand access to MRI-guided adaptive radiotherapy for patients in the North of England and Scotland.

* Treatment figure correct as of 23 September 2026.

The NHS England evidence review identified prospective and retrospective case series of renal SABR, while Clinical Panel subsequently considered additional evidence specifically relevant to patient with T1b disease where surgery wasn’t clinically appropriate.¹

Key findings included:

• Local control: in a prospective series (n=15), local control was 94.4% at six and 12 months (95% CI, 66.6%–99.2%).³ In a separate retrospective series (n=74), cumulative local failure was 5.85% at one year and 7.77% at two years.⁴

• Progression-free survival: at two years, progression-free survival was 89.7% (n=74),⁴ 89% (n=33; 95% CI, 78%–100%),⁵ and 77.5% (n=81)⁶ across three series.

• Renal function: mean eGFR decreased by 5.4 mL/min at 6 months in one prospective series (n=19; 95% CI, −10.3 to −0.6).³ In a retrospective series (n=74), eGFR declined significantly over a median 27.8-month follow-up (p<0.0001), with a median reduction of 14 mL/min at 4 years.⁴ Tumour diameter ≥4 cm was associated with an increased likelihood of an eGFR reduction ≥15 mL/min (n=81; OR, 4.21; 95% CI, 1.16–15.31; p=0.029).⁶

• Safety: in a prospective series (n=33), 21% of patients experienced at least one grade 2 adverse event and 3% experienced a grade 3 event. No grade 4 events were reported.⁵

• Survival compared with observation: in a retrospective database analysis, 104 patients received SABR and 18,241 were managed with observation. SABR was associated with a lower risk of death (HR, 0.56; 95% CI, 0.39–0.79; p<0.001). Higher-dose SABR (BED₁₀ ≥100 Gy; n=62) was associated with a lower risk of death (HR, 0.34; 95% CI, 0.19–0.60; p<0.001), while lower-dose SABR (n=42) was not associated with a statistically significant survival difference (HR, 0.90; 95% CI, 0.58–1.40; p=0.64).⁷

The evidence remains limited by small cohorts and a lack of randomised comparative studies. The survival analysis was observational, so residual differences between the SABR and observation groups may have influenced outcomes. Clinical Panel nevertheless considered the overall evidence sufficient to support routine commissioning, alongside continued collection of clinical and safety outcomes.

Dr Philip Camilleri, Clinical Director of Uro Oncology at GenesisCare, and Dr Dan Ford, Clinical Oncologist and Specialist Advisor of Uro Oncology at GenesisCare, provide the following joint clinical perspective on the NHS England commissioning decision.

“The commissioning decision recognises that renal SABR can have a role in that setting. The evidence reviewed by NHS England consistently showed low rates of local failure, but it is also important to be clear about the limitations: most of the data come from small, non-randomised series, and the certainty of evidence was rated very low. This makes careful patient selection particularly important.

“At GenesisCare, we have been treating patients with renal SABR for several years, including selected patients using MRI-guided adaptive radiotherapy, so we have developed considerable experience in assessing which patients are most likely to be suitable. For a patient who cannot undergo surgery, the decision needs to take account of tumour size and location, baseline renal function, proximity to surrounding organs and the patient’s wider health.

“For colleagues managing a patient with localised T1b renal cancer who cannot undergo surgery, we would encourage referral for specialist review. Our Urology SABR Advisory Team can review the imaging and clinical information and advise whether SABR is appropriate, and which treatment approach may be most suitable. Where those factors are favourable, SABR gives us a non-invasive way of treating the primary tumour without an operation or general anaesthetic. For carefully selected patients, this provides an additional local treatment option while the disease remains confined to the kidney.”

GenesisCare is ready to accept renal SABR referrals from clinicians across the UK. Our Urology SABR Advisory Team can provide specialist advice, review imaging and clinical information, and support treatment decision-making for patients who may be suitable for conventional or MRI-guided adaptive SABR.

To discuss a patient, seek advice on suitability or make a referral, please contact:

urologysat@genesiscare.co.uk

Where required, we can also support patients travelling for treatment with transport and accommodation.

1. NHS England. Clinical Priorities Advisory Group Summary Report: Stereotactic Ablative Body Radiotherapy for Primary Kidney Cancer. Unique reference no. 2332. Clinical Priorities Advisory Group meeting; May 11-13, 2026. Accessed September 23, 2026.
2. National Institute for Health and Care Excellence. Kidney Cancer: Diagnosis and Management. NICE guideline NG256. Published March 19, 2026. Accessed September 23, 2026.
3. Zarkar A, Henderson D, Carver A, et al. First UK patient cohort treated with stereotactic ablative radiotherapy for primary kidney cancer. BJUI Compass. 2023;4(4):464-472. doi:10.1002/bco2.199
4. Glicksman RM, Cheung P, Korol R, et al. Stereotactic body radiotherapy for renal cell carcinoma: oncological and renal function outcomes. Clin Oncol (R Coll Radiol). 2023;35(1):20-28. doi:10.1016/j.clon.2022.06.007
5. Siva S, Pham D, Kron T, et al. Stereotactic ablative body radiotherapy for inoperable primary kidney cancer: a prospective clinical trial. BJU Int. 2017;120(5):623-630. doi:10.1111/bju.13811
6. Correa RJM, Louie AV, Staehler M, et al. Stereotactic radiotherapy as a treatment option for renal tumors in the solitary kidney: a multicenter analysis from the IROCK. J Urol. 2019;201(6):1097-1104. doi:10.1097/JU.0000000000000111
7. Grant SR, Lei X, Hess KR, et al. Stereotactic body radiation therapy for the definitive treatment of early stage kidney cancer: a survival comparison with surgery, tumor ablation, and observation. Adv Radiat Oncol. 2020;5(3):495-502. doi:10.1016/j.adro.2020.01.002