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Evaluation and Management of the Small Renal Mass. Jeffrey A. Cadeddu, M.D. Professor of Urology and Radiology UT Southwestern Medical Center. Differential of the Renal Incidental Mass. Cyst (vast majority of ‘masses’) Simple Complex Tumor Carcinoma Benign. Renal Cysts. “Kidney Cancer”.
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Evaluation and Management of the Small Renal Mass Jeffrey A. Cadeddu, M.D. Professor of Urology and Radiology UT Southwestern Medical Center
Differential of the Renal Incidental Mass • Cyst (vast majority of ‘masses’) • Simple • Complex • Tumor • Carcinoma • Benign
“Kidney Cancer” • Not all “Kidney Cancer” created equally • Histologic subtyping is critical to understanding natural history of disease
The Heidelberg classification of renal cortical tumors • Subdivides renal cell tumors into benign and malignant neoplasms by documented genetic abnormalities • Benign: Angiomyolipoma and Oncocytoma • Malignant tumors sub-classified into: • conventional RCC • papillary RCC • chromophobe RCC • collecting duct carcinoma • medullary carcinoma • unclassifiable Kovacs G, J Pathol 1997
Histologic Findings in 21st Century • Duchene et al. UTSW, Urology 62: 827, 2003 • Modern series 1999 - 2002
Epidemiology of RCTLack of Mortality Reduction 33% Rise 25% Rise Jemal A, CA Cancer J Clin 2005
Not All Malignant RCT are Created Equal • McKiernan, et al. J Urol 2002 • Partial nephrectomy for renal cortical tumors (T1a) -pathologic findings and impact on outcome • Histological findings • conventional 148 cases (51%) • papillary 54 (18%) • oncocytoma 32 (11%) • chromophobe carcinoma 21 (7%) • 5-year recurrence rate of 12% for conventional • No recurrence seen in any other RCT • Caveat – presumably papillary were all Type 1 • Type 2 present higher grade and stage
Biopsy in 2012 • High suspicion for benign dz • Young women with solid tumor – AML? • Suspect tumor of low metastatic potential • Chromophobe RCC • Papillary RCC, Type 1 • Poor surgical risk • High risk of chronic kidney dz
New Descriptive Evaluation Tool • RENAL Nephrometry (Uzzo et al)
2012: Nephron-sparing for Small Renal Tumors (< 4 cm = T1a) • Partial Nephrectomy • Ablation – Cryo or RFA • Surveillance
Appropriate surgical choice MUST weigh concern for CRI and GFR? • Thus nephrectomy should be rare • High RENAL score and high GFR
Why is maintaining GFR important? Clinical impact: Increased cardiovascular death Weiner et al, 2004 N = 22,634, pooled from 4 community studies (composite includes MI, fatal CHD, nonfatal and fatal stroke, mortality)
Clinical impact: Increase in mortality, morbidity Go et al NEJM, 2004
Impact of Preserving GFR in Patients with Renal Tumors • Huang, Russo et al. J Urol 181:55, 2009 • 2500 RN vs. 500 PN (SEER and Medicare)
Fundamentals of Renal Cortical Tumor Management • 20% are benign • 30% of T1a RCC are low metastatic potential • No impact of detecting incidentalomas on RCC stage migration or mortality reduction • Standard surgical treatments increase risk of developing CKD • CKD Stage 3 associated with 20% increase risk of death and 40% increase risk of cardiac event • Saving kidney function more likely to impact survival!!!
Active Surveillance: The UltimateNephron-Sparing Rx • Volpe and Jewett, Nat Clin Prac Urol 2005.
Incidental Tumors at Autopsy • Incidence at autopsy of RCC before widespread imaging • Hellsten et al. Eur Urol 1990 • Wunderlich et al. Eur Urol 1998 • 67 – 74% of RCC undetected until death!
Active Surveillance: The UltimateNephron-Sparing Rx • Kunkle, Uzzo, et al. J Urol 177849, 2007. • 106 tumors, median 2 cm, observed > 12 mo • 33% NO growth median 25 months • Median growth = 0.2 cm/yr • Of surgery case, ~ 85% RCC • 1 case progressed to mets (3 in literature) • 54 month f/u, increase 2 to 8 cm!
Active Surveillance: The UltimateNephron-Sparing Rx • Hollingsworth et al. Cancer 109:1763, 2007 • Competing risk analysis 26,000 pts • T1a – 5% risk death w/i 5 years • T2 – 27% risk death w/i 5 yrs, despite surgery • > 70 yo, 28% competing-cause mortality, regardless tumor size
Progression Risk of Active Surveillance • Uzzo et al. Cancer 2009 • Metastatic progression 1.3% (2/154) • 1 during active surveillance • 1 after delayed intervention • Rosales, Benson, McKiernan, Landman et al. J Urol 183:1698, 2010. • Median f/u 35 mo • 2% metastases
Progression Risk of Active Surveillance • Zini et al. BJUI 103:899, 2009 • SEER analysis (> 10k pts T1a) • Compared 433 with AS to 9858 nephrectomy • At 1, 2 and 5 yrs survival advantage of Surgery vs. AS was 5.2%, 6.5% and 9.4% • Advantage same when matched by age, size and yr diagnosis.
Disadvantages to Active Surveillance • Real metastatic potential • Patient longevity variable and not accurately predictable • Cost of frequent surveillance studies (+ biopsy?) • Anxiety
Laparoscopic/Robotic Partial Nephrectomy • State-of-the-Art! • Alternative to Open Partial Nephrectomy
Complications of LPN:CCF 200 cases(Ramani et al. J Urol 2005)
Perioperative Outcomes Following Lap/Robotic Partial Nephrectomy: role of R.E.N.A.L NS(Liu et al, WJU in press)
Myths(Simmons et al, J Urol 2008) • Pneumoperitoneum • No study reported long term detrimental effects of pneumo on human kidneys • Maybe renoprotective (preconditioning)? • Artery only vs. artery and vein clamping • No study shows improved ischemia or renal function • Increases risk of obscured visualization • Manual Compresion / Regional Ischemia • No study demonstrating renal function benefit
117 patients – pre and post op renal scans at 6 months • 52 OPN, 62 LPN • Multivariate analysis to study factors affection GFR
39 patients – normal Cr, LPN or OPN • Ischemia time 24.5 min LPN, 38 min OPN • Estimated GFR at 1 yr • Volumetric calculations based on pre and post CT
Alternative to Partial Nephrectomy?? • TUMOR ABLATION • LAPAROSCOPIC or PERCUTANEOUS • freeze or heat • Cryosurgery • Radiofrequency ablation (RFA)
Advantages of Ablation • Nephron-sparing • Many tumors are slow growing/ low aggressiveness • Low morbidity • Fewer complications • Outpatient (or overnight stay only) • Ease of radiographic follow up
Possible Risks • Tumor left in situ • Ablation success defined as NO enhancement on CT/MRI and tumor shrinkage • Long term RCC control unknown
Laparoscopic Cryoablation Technique • Usually mobilize kidney to place US probe on opposite side from tumor • Expertise in US and manipulation of laparoscopic probe (and/or need radiologist) • Ablation completed = ice ball beyond tumor margins
Pre Cryo Cryo at one year Promising alternative to surgical excision
Laparoscopic RFA Technique • Mobilize only tissue near tumor (unlike cryo) • RF probe positioned per manufacturer, US to visualize probe/tines optional • Visualize changes during ablation
Pre-ablation 3 Months Post RFA Results Lesion Progression: 1. Wedge/spherical non-enhancing 2. Gradual contraction residual scar (Matsumoto et al. J Urol, 172:45, 2004) 12 Months Post
Tracy CR, et al. Durable oncologic outcomes following radiofrequency ablation(RFA): experience from treating 243 small renal masses over 7.5 years. Cancer 2010. Baseline characteristics of tumors treated with RFA separated by total number of patients and those with ≥3 years of follow-up.
Local Recurrence • Growth or enhancement after 6 weeks: 3.7% (n=9) • 3- and 5- year recurrence-free survival rates of 93%