Is partial removal of the kidney better than removing the whole kidney for patients with intermediate-size kidney tumours?

INTERVENTION: Potential participants will be identified through hospital urologist clinics and screening in local and regional specialist multi‐disciplinary teams. Adults with suspected or confirmed clinically localised kidney cancer on imaging with a normal functioning kidney on the other side and considered suitable for both minimally invasive (keyhole) radical or partial nephrectomy will be considered. Those with suspected kidney cancer are eligible for inclusion due to the low uptake of biopsy amongst patients (as described in section A6‐2). Potential participants being considered for open surgery will be excluded from the study as open surgery has significantly more complications than keyhole surgery and is generally reserved for tumours which are outside the inclusion criteria of the study. Eligible participants will be given information about the study. Those who are interested in taking part will discuss the surgical options and the study with a member of the clinical team during a face‐to‐face or virtual consultation. If the participant decides to give their consent, they will be asked to sign a consent form (electronic or hard copy, as per preference) and complete a baseline questionnaire. Participants can complete this at a consultation or at home. If completed at home, this may be supported by a telephone call from the site (if the participant agrees to this contact) and the consent form and baseline questionnaire, if done as hard copy, will be returned through the post. The local research team will complete a baseline case report form collecting data on age, sex, ethnicity, height, weight, postcode, medical history, smoking status, kidney function (eGFR ‐ measured by a blood test, the standard of care), tumour size and location (measured on imaging, the standard of care) CONDITION: Renal cancer ; Cancer PRIMARY OUTCOME: 1. Renal function preservation by estimated glomerular filtration rate (eGFR) measured using a blood test and standard procedures at baseline, 1 week and 1 month after surgery and 6, 12 and 24 months after randomisation; 2. Surgical complications measured using the Comprehensive Complications Index (CCI) to 3 months after surgery SECONDARY OUTCOME: 1. Health‐related quality of life (HRQoL) measured using the EORTC Core Quality of Life questionnaire (EORTC QLQ‐C30) and the 36‐Item Short Form Health Survey (SF‐36) acute version (1‐week recall) participant questionnaires at baseline, 1 week, 1 month and 3 months after surgery and 3, 6, 12, 18 and 24 months after randomisation; 2. Cost‐effectiveness (quality‐adjusted life‐year and costs) measured using case note reviews and participant questionnaires at baseline, surgery, 1 week, 1 month and 3 months after surgery and 3, 6, 12, 18 and 24 months after randomisation; 3. Quality of recovery capturing length of stay measured using the 15‐item Quality of Recovery‐15 (QoR‐15) scale participant questionnaire at 1 week, 1 month and 3 months after surgery; 4. Rates of positive surgical margin rates and retreatment / surgical revision measured by case note review (pathology report) at surgery and 24 months after randomisation; 5. Recurrence‐free and overall survival including local recurrence measured by case note review at 24 months after randomisation; 6. Cardiovascular events (non‐fatal heart attack, non‐fatal stroke and cardiovascular death) measured by case note review at 24 months after randomisation; 7. Progression to chronic kidney disease stages 3, 4, and 5 by estimated glomerular filtration rate (eGFR) measured using a blood test and standard procedures at baseline, 1 week and 1 month after surgery and 6, 12 and 24 months after randomisation; 7. Operative conversion to radical nephrectomy measured by case note review at surgery; 8. Patient acceptability measured using interviews in embedded mixed methods trial process evaluation and participant questionnaire at 3 months after surgery INCLUSION CRITERIA: 1. Adults > = 18 years 2. Newly diagnosed clinically localised renal cancer (suspected on cross‐sectional imaging or histologically confirmed) 3. Local multi‐disciplinary review identifying those cases thought to be suitable for both minimally invasive RN or PN; (for minimally invasive we mean laparoscopic or robotic surgery; cases where open surgery is planned are not eligible) 4. Cross‐sectional imaging showing a single tumour, stage T1 (up to 7cm), where there is equipoise in the MDT and willingness to recruit into the trial 5. On imaging, evidence of a radiologically normal contralateral kidney 6. Patients that have been fully counselled of all the available treatment options (including non‐surgical approaches, where appropriate) 7. Able and willing to give informed consent to participate and to participate in study procedures