By Jean-Michel Correas, Anaelle Sadoun, Christophe Delvaud, Guillaume Reichert, Clara Tescher, Sylvain Bodard - Service de Radiologie Adultes, Groupe Hospitalier Necker Enfants-Malades, Paris.
Kidney tumor treatment came under the spotlight at JFR 2026 in Friday morning’s dedicated pedagogic session, listed in the program with a heart emoji as one of the ‘president’s favourites’. The session, organized by the Société d'Imagerie Génito-Urinaire (SIGU), was aimed at all radiologists, whether interventional or not.
Minimally invasive thermoablation techniques are evolving rapidly, as is the software used for guidance and predictive outcome verification, with a view to improving the reproducibility and tolerability of the procedures, noted the session’s speakers.
However, hereditary kidney tumors present specific challenges, and the radiologist must be able to consider this diagnosis, the presenters stressed in an article on the topic published during the congress. In these cases, imagers will subsequently be involved in family screening and the monitoring of treated patients.
In addition, imaging of patients treated with thermal ablation presents very specific challenges, and here too, the radiologist will be responsible for diagnosing incomplete treatment, local or contralateral recurrence, or distant spread. They noted that biopsy of a lesion suspected of recurrence is not recommended, and it is contrast-enhanced imaging that establishes the diagnosis.
In the case of metastatic cancer, management and survival have been transformed by the development of new treatments, such as immunotherapy and mTOR inhibitors, they continued.
Extra challenges
Thermoablation of renal tumors presents additional challenges due to the high blood flow in renal cancers and the adjacent renal parenchyma, the small volume of viable renal cortex, and the sensitivity of the urinary tract to temperature changes (which may lead to urinary fistulas or strictures), the experts noted.
The proximity of the digestive tract, the pancreas, the spleen or the liver necessitates the use of dissection techniques (using fluid and/or gas) to ensure a safety margin. Protection of the urinary tract can also be achieved by injecting heated or cooled saline (depending on the technique) via a nephrostomy or ureteral catheter, or via a JJ stent.
A 76-year-old patient with a single kidney following total right nephrectomy for renal carcinoma.
Seven years later, an endophytic tumour developed in the left kidney and was treated by tumourectomy (grade 3 clear cell renal carcinoma, with positive margins), with preserved renal function (eGFR CKD EPI 50–55 ml/min).
A CT scan performed 2 years after the left renal tumour resection shows a local endophytic recurrence measuring 18 mm in greatest diameter (arrows) on the cortical phase of the nephrography (A), which is increasing in size. On the secretory phase, it is in contact with a calyceal stem and two calyceal bases (arrow in B).
Treatment was carried out using cryotherapy with a V-probe (Varian) opened to 25 mm, following the placement of a JJ stent to prevent secondary stenosis of the lower calyceal group or the pyelo-ureteric junction.
The one-year follow-up after treatment and removal of the JJ stent shows a satisfactory outcome with no hypervascular local recurrence (C) or dilatation of the urinary tract (D). Follow-up must be strictly maintained due to the risk of local, regional or distant recurrence.Images and caption courtesy of Dr Jean-Michel Correas et al. and SFR.
Thermoablation techniques are constantly evolving to improve their efficacy and the reproducibility of the volume of parenchyma destroyed. Furthermore, a range of solutions are available to improve needle guidance and aim to predict the completeness of ablation based on the electrodes (number and position) and recognized safety margins. They described how oncological outcomes depend on a range of factors, particularly the tumor’s diameter and histology. However, whilst recent meta-analyses show results similar to those of partial surgery, the risk of local recurrence is nevertheless higher, they noted.
In the general population, there is no routine screening for kidney tumors. However, a diagnosis of hereditary cancer may be considered depending on the presence of associated lung conditions (cysts, pneumothorax, etc.), kidney conditions (cysts, angiomyolipomas, cystic tumours, etc.), pancreatic (cystadenomas, multicystic disease, neuroendocrine tumours, etc.), adrenal, or even cerebral, ocular, cardiac or uterine lesions, etc.
In the context of von Hippel–Lindau disease, an abdominal MRI scan may be recommended every two years from the age of 15, possibly alternating with a renal ultrasound scan if the MRI result was normal. Some forms are highly aggressive, such as those associated with a fumarate hydratase mutation in the context of HLRCC syndrome or succinate dehydrogenase (SDH)-deficient carcinomas. In such cases, prompt surgical treatment should be offered. For von Hippel-Lindau disease, a HIF-2α inhibitor, belzutifan, enables the management of patients with systemic lesions and is very well tolerated.
Patients undergoing thermotherapy must undergo regular imaging surveillance (primarily CT and MRI scans to allow for comparative assessment). This necessarily requires the injection of a contrast agent. Contrast uptake, particularly when nodular and in the deep regions of the tumor (endophytic or sinus-like localization), is suspicious but requires verification of any increase in size. A biopsy is not recommended and is only of value if positive. Above all, monitoring must focus not only on the treated lesion but also on detecting other local, regional or distant sites.
The presenters noted that the role of patient organizations is absolutely essential. Indeed, they help to inform, reassure, support and disseminate important information, particularly regarding monitoring. All too often, given the systemic nature of the condition and the repeated examinations and surgical procedures, patients discontinue monitoring after several years.
Editor's note: This is an edited version of a translation of an article published in French online by the SFR in its congress newsletter JFR Actu’. Translation by Frances Rylands-Monk. To read the original version, go to JFRActu’: https://www.radiologie.fr/thermoablation-des-tumeurs-du-rein-une-alliance-entre-radiologues-urologues-et-patients
