study to evaluate the efficacy of percutaneous cryoablation for renal tumours < 4cm in patients who are not candidates for partial nephrectomy

Conditions: Renal Tumors Less Than 4 cm

Summary: the main objective is to evaluate the oncologic efficacy of percutaneous cryoablation of renal tumors smaller than 4 cm in patients with renal cancer that cannot be offered a partial nephrectomy. the oncologic outcome will be assessed by the presence or absence of residue or recurrence during a follow-up by mri performed the first 12 months (m1, m3, m6, m12).


Eligibility criteria:
inclusion criteria: patients should have the following characteristics: * about 75 years, or * whatever the age: * a context of family-type tumor (vhl, hereditary carcinoma, tubulo-papillary ...); * or solitary kidney, when the tumor is not easily accessible for nephron-sparing surgery: malignant centro-hilar or intra-parenchymal; * or in a local recurrence (single or multiple) after partial nephrectomy (within a limit of 3 tumors to be treated); * or in a subject with impaired renal function and therefore at risk of severe renal insufficiency (risk defined by a creatinine clearance below 30 ml / min by mdrd formula); * and who do not present any contra-indication for cryoablation treatment. the tumor(s) should meet the following criteria: * presence of one to three solid tumors of the native renal parenchyma with a largest diameter less than (or equal to) 40 mm, which corresponds to a maximum volume of about 32 cc, as measured by mri. * a preoperative mri is essential since this technique presents a higher sensitivity. this control will also give more consistency to the evaluation of the radiological semiology at follow-up. * and its/their location(s) will be accessible to a percutaneous approach. the search of metastases, including a thoracic ct scan, should be negative. exclusion criter ia: * - partial nephrectomy feasible in good technical and oncologic conditions in patients under 75 years and in the absence of family tumors. * contraindication to any form of sedation. * irreversible coagulopathy * tumor\> 4cm * contraindication to mri or gadolinium (proven allergy). nb: patients with a glomerular filtration rate below 30 ml/min/1, 73 m2 will be injected with a single dose of the macrocyclic gadolinium with the highest thermodynamic stability (dotarem or prohance), given the united recommendations of afssaps and ema (european medicines agency) \[45\]. on the contrary, the linear molecules of gadolinium, due to their lower stability, will be contra-indicated because of the risk of systemic nephrogenic fibrosis (fns). * recurrence on the same location after a procedure performed out of the thermoablation protocol. * biopsy proven benign tumor * predominantly cystic tumor, defined by a necrotic content constituting over one third of tumor volume * presence of endo-venous extension, of proven secondary extensions, visceral or in the lymph nodes (especially lung). in this regard, a thoracic ct scan will be routinely required before treatment, according to the recommendations of urological societies. * psychiatric disorders and adults under guardianship * pregnancy or breastfeeding * minor patients * legal safeguard * participation in another clinical trial