AURORAX-0087A: GAG Scores for Surveillance of Recurrence in Leibovich Points ≥5 Non-metastatic ccRCC

Inclusion Criteria: Pre-screening inclusion criteria * Size of primary tumor \>4cm (\>cT1a) in greatest dimension on pre-operative abdominal CT-scan * Size of primary tumor ≤4cm is allowed if pre-operative abdominal CT-scan shows suspected RCCs with radiological sign of venous tumor thrombus (renal vein or caval). * Pre-operative CT-scan of chest and abdomen show no signs of metastatic disease * Localized and biopsy proven clear cell RCC (ccRCC) under active surveillance which at timepoint of study recruitment, opted for surgery because of growth rate of primary tumor to a size \> 4cm * Elected for curative intent surgery for RCC Final screening inclusion criteria * Any gender being 18 years or older at timepoint of final inclusion * In postoperative pathology report shown to be ccRCC subtype according to 8th Edition of the American Joint Committee on Cancer (AJCC) * Leibovich points (LP) ≥5 according to Leibovich score system (2003) * If pathology report shows multiple subtypes in same tumor, as long as the majority of tumor is ccRCC (\>50%), participant can be included Exclusion Criteria: Pre-screening exclusion criteria * TNM-stage T(any) N(any) M1 according to AJCC, i.e. metastatic disease at diagnosis * Absence of preoperative chest imaging (chest CT) within 60 days prior to primary surgery * Previous history of curatively treated for other cancers, still not deemed fully cured and participant still under surveillance for said cancer * Participants offered active surveillance for RCC instead of curative intent surgery * Participants offered any type of thermal ablation treatment instead of surgery, i.e. LP cannot be assessed Final screening exclusion criteria * Participants with AJCC cN0 status at preoperative imaging in whom a clinically suspicious regional lymph-node metastases (enlarged lymph node(s)) is noted during primary surgery, but who subsequently do not undergo any lymph node dissection. (Note: participants with cN0 status at pre-operative imaging and no clinical signs of regional lymph node metastases during primary surgery can still be included irrespective of lymph node dissection having been performed, i.e. being pN0 or pN1 if it is performed or pNx if it is not performed) * Participants with AJCC cN1 status at pre-operative imaging in which lymph node dissection is not performed (i.e. pNx). * Elected for any adjuvant therapy (i.e. systemic therapy) outside or within any clinical study * Non-clear cell RCC histology or benign tumor (i.e. oncocytoma and angiomyolipoma, which are the most common benign types, but also any other rare types of benign renal tumors) after pathological analysis * Any hereditary form of RCC (e.g. Von Hippel-Lindau, Birt-Hogg-Dubé, Hereditary Papillary RCC) * RCC with pure sarcomatoid differentiation, also called sarcoma of the kidney * Previous history of curatively treated for RCC with a suspected de novo RCC in the remaining kidney tissue * Prior or current use of instillation therapy with hyaluronic acid and/or chondroitin sulfate (HA-CS). * Use of heparin, including low molecular weight heparin (e.g. Enoxaparin, Dalteparin, Tinzaparin) for concurrent disease in need of blood dilution (e.g. ongoing deep vein thrombosis or lung emboli). Note: use of of heparin for thrombus prophylaxis in conjunction with primary surgery or postoperatively ≤4 weeks will be allowed. * Patients who were not radically operated during primary surgery with the exception of histological positive surgical margin in participants who have undergone partial nephrectomy.