The team of the Radiation Oncology Department at Hospital Clínic de Barcelona, part of the Clínic Barcelona Comprehensive Cancer Centre (4CB), has treated a primary kidney tumour with stereotactic body radiation therapy (SBRT) in a single session for the first time. The treatment was delivered at the department's Granollers site to an elderly patient for whom surgery posed a high risk. The team had previously treated a first patient with this technique in three sessions at the Clínic site in Barcelona.
The standard treatment for localised kidney cancer is surgery. Although it is an uncommon tumour, its incidence is rising among older people, partly because more and more lesions are being detected incidentally on imaging tests performed for other reasons. Many of these patients have other conditions that make surgery risky. In addition, in patients with a single kidney, removing part or all of the kidney can lead to kidney failure or worsen pre-existing kidney failure, even to the point of requiring dialysis.
"We needed to find an alternative for these patients that was less invasive and that, at the same time, would allow us to preserve kidney function," explains Dr Gerard Meca, radiation oncologist in the Department. Until now, the option was thermal ablation techniques (cryotherapy, radiofrequency or microwave ablation), which are minimally invasive but can only be used for small, peripheral tumours.
A tumour once considered resistant to radiotherapy
For years, kidney cancer was considered resistant to conventional radiotherapy, which delivers low doses spread over many sessions. SBRT, by contrast, concentrates very high doses in a few sessions, from one to five, with great precision. In the case of the kidney, a recent study has shown that it can be delivered in a single session for tumours smaller than 4 centimetres and in three sessions for tumours between 4 and 10 centimetres.
"It is a non-invasive treatment, because it is external radiotherapy, and it is done on an outpatient basis: the patient does not need to be admitted," says Dr Meca. Studies show excellent oncological outcomes, very good tolerance and good preservation of kidney function. It also makes it possible to treat tumours of up to 10 centimetres, a size beyond the reach of thermal ablation techniques.
From clinical trial to practice in just a few months
The technique has been introduced following the long-term results of the FASTRACK II trial, an international multicentre phase II study of 70 patients with localised kidney cancer who were not candidates for surgery. The results were presented in May 2026 at the congress of the European Society for Radiotherapy and Oncology (ESTRO) in Stockholm and published simultaneously in the prestigious journal The Lancet Oncology.
The study shows 100% local control of the disease up to seven years after treatment, with close to 80% of patients free of metastases, a very favourable toxicity profile and good preservation of kidney function. SBRT has already been included in the European urology clinical guidelines as an alternative to be considered in selected cases.
"We already use this technique for other tumours, and when the positive results of the pivotal study in renal carcinoma were presented, we immediately brought it into clinical practice," says Dr Meritxell Mollà, radiation oncologist and Head of the Radiation Oncology Department.
The first case
The patient had a 2.5-centimetre tumour located in the central part of the kidney and pre-existing chronic kidney failure. Because of its location, surgery would have required removing the entire kidney, with a risk of ending up on dialysis. He did not meet the criteria for thermal ablation either.
"A few years ago we would not have been able to offer him curative treatment without surgery," recalls Dr Meca. Two weeks after the session, the patient was feeling very well and had no symptoms or side effects. "From here on, we will assess the tumour's response with imaging tests over the coming months," he adds.
A single hospital visit
A single dose of 26 Gy, instead of the 42 Gy delivered over three sessions used for larger tumours, is unusual even in experienced centres. It requires the whole team to be present during treatment and more time for verification. For patients, however, it has clear advantages.
"If you can make it possible for the patient to come to hospital only once, even if the treatment takes a little longer that day, it is a major advantage," says Dr Mollà. "These are older people, often taking multiple medications. A patient on anticoagulants, for example, does not need to change their medication, because it is not an invasive procedure and does not require anaesthesia. We are offering a therapeutic alternative with a very high level of evidence that did not previously exist for these patients," the specialist concludes.
Health equity and expertise
The Granollers site is part of Hospital Clínic, within the framework of the C-17 Network, and the fact that the patient was able to receive treatment there is an example of health equity: he had access to the same technique and the same team without having to travel to Barcelona.
Patients from Hospital General de Granollers, Mollet, Vic, Sant Celoni or Campdevànol can therefore access this technique close to home. "It means bringing a technique of this kind closer to people who may not have a tertiary hospital nearby," explains Dr Meca.
Dr Mollà stresses that the key factor is expertise: "You need good infrastructure, but above all a good team. You can have a Ferrari and not know how to drive it. With a decade of experience and a very high patient volume, the Department also has respiratory control systems that ensure treatment precision in organs that move with breathing, such as the liver or the kidney. This expertise, built up over years, is what allows Clínic to offer every patient the best available treatment, whichever site they are treated at."
A multidisciplinary decision
All cases are assessed by the uro-oncology multidisciplinary committee. From now on, patients with localised kidney cancer who are not candidates for surgery, or who do not wish to have surgery, and who are not candidates for thermal ablation either, will be able to receive this treatment.
In the words of Dr María José Ribal, Head of the Uro-oncology Unit, "our Unit is the natural setting for incorporating new techniques into the treatment of urological cancer. We bring together all the disciplines involved in patient care, and each one contributes an essential piece. This shared perspective allows us to assess each patient as a whole: their tumour, but also their age, any other conditions they may have, their kidney function and their preferences. With every new option, the question is not only whether it works, but for which patient and at what point it brings real benefit. Answering that question is precisely what a multidisciplinary unit does."
On the specific case of applying this new technique, the specialist adds: "In this spirit, we are open to innovation. The promise of SBRT opens the door to treating patients to whom we cannot offer surgery. It also broadens the options we already have in kidney cancer: surgery, ablation techniques, active surveillance and systemic treatments. Ensuring that each patient receives the most appropriate option, decided together with them and with the whole team, is what gives the Unit's work its meaning."
