***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND AND OBJECTIVES Prospect i ve r and omized comparison of intermediate-term outcomes of patients with small renal tumors who were treated with partial nephrectomy ( PN ) or microwave ablation .  METHODS Of 102 selected patients with solitary small renal tumors who had prospect ively completed at least 2 years of follow-up since December 2004 , r and omizedly , 54 had either open ( 19 ) or laparoscopic ( 35 ) PN and 48 had laparoscopic ( 28 ) or open ( 20 ) microwave ablation .  Patient and tumor characteristics , surgical data , complications , histologic and oncologic data , and functional data of the two approaches were compared . RESULTS Patients in microwave ablation group and PN group matched for age , sex , American Society of Anesthesiologists score , body mass index , and tumor size and were respectively followed for median 32 and 36 months . Surgical and hospitalization times were comparable in both groups . Estimated blood loss , complication rates , and decline of postoperative renal function were significantly less in the microwave ablation group ( P = 0.0002 , P = 0.0187 , and P = 0.0092 , respectively ) . The decrease in estimated glomerular filtration rate at the last available follow-up was similar in both groups ( P = 1.0000 ) . There were no disease-specific deaths . Kaplan-Meier estimates of overall local recurrence-free survival at 3 years were 91.3 % for microwave ablation and 96.0 % for PN ( P = 0.5414 ) ; the respective numbers for renal cell carcinomas were 90.4 and 96.6 % ( P = 0.4650 ) . CONCLUSIONS Microwave ablation can be also safely and efficiently done for patients with small renal tumors . This intermediate analysis showed that microwave ablation provides favorable results compared to PN . However , longer term data are still needed WITH the increasing incidence of renal cell carcinoma ( RCC ) in the United States and the increasing proportion of patients with tumors detected at an early stage ( 1–5 ) , nephron-sparing approaches are becoming more popular . These alternatives to radical nephrectomy include partial nephrectomy , wedge resection , and , more recently , in situ thermal ablation . Five-year survival rates after partial nephrectomy are equivalent to those after radical nephrectomy ( 6–8 ) , supporting the rationale of in situ tumor destruction to further reduce morbidity and invasiveness . In situ thermal destruction of RCC uses techniques that destroy tumor tissue through heating ( eg , radiofrequency [ RF ] ablation , microwave ablation , laser interstitial therapy , high-intensity focused ultrasound [ US ] ) or freezing ( eg , cryotherapy ) . Each of these techniques relies on controlled energy delivery to minimize collateral damage to normal renal parenchyma and other surrounding structures . In the United States , RF ablation and cryoablation are currently the most widely used techniques for in situ RCC destruction . Thermal ablation of RCC may be performed percutaneously , laparoscopically , or through open surgery . Our current underst and ing of the role of percutaneous thermal ablation in the management of primary RCC is limited by a paucity of prospect i ve studies ( 9,10 ) . Given the relative newness of this technology , most series to date report short-term or midterm outcomes , with no reports extending to 5 years of survival outcomes . No r and omized trials have been performed to date comparing thermal ablation against a gold st and ard ( ie , partial nephrectomy ) or against other thermal ablation techniques . The optimal size range of RCC amenable to thermal ablation has not been clearly defined and is closely related to anatomic factors that influence the ability to deposit sufficient thermal dose to coagulate tissue , including proximity to major vessels and the urinary collecting system , which can act as a heat sink . The kidney has approximately four times the blood flow of the liver , so convective heat loss during thermal ablation is potentially significant ( 11 ) . The role of percutaneous thermal ablation compared with laparoscopic or open thermal ablation also remains a topic of controversy . The combination of thermal ablation with other imageguided therapies ( eg , transcatheter embolization ) and adjuvant therapies such as chemotherapy and antiangiogenic agents for larger RCCs in patients who are poor operative c and i date s is another potential use of this technique . Although most recent reports of percutaneous RCC ablation have involved RF ablation , other ablation technologies are now available with percutaneous applicators ( eg , cryoablation , microwave , laser interstitial therapy ) , and reporting st and ards should be uniform for all forms of energy-based ablation . This document provides recommended reporting st and ards for physicians performing percutaneous thermal ablation of primary RCC and will serve as a template in the design of clinical trials to further evaluate this technology . From the Section of Vascular and Interventional Radiology , Department of Radiology ( T.W.I.C. ) , New York University School of Medicine , New York , New York ; Department of Radiology ( S.F.M. ) , University of Western Ontario , Peterborough Regional Health Center , Peterborough , Ontario , Canada ; Department of Radiology , Gastrointestinal/Genitourinary Division ( D.A.G. ) , Massachusetts General Hospital ; Department of Radiology ( S.N.G. ) , Beth Israel Deaconess Medical Center , Boston ; Department of Radiology ( C.J.G. ) , Lahey Clinic Medical Center , Burlington ; Department of Radiology ( D.A.P. ) , University of Massachusetts Memorial Health Care , Worcester , Massachusetts ; Department of Radiology ( T.B.K. ) , University of California San Diego Medical Center , San Diego , California ; Department of Radiology ( D.S. ) , The Reading Hospital and Medical Center , Reading , Pennsylvania ; and Department of Radiology ( J.F.C. ) , University of Colorado Health Sciences Center , Denver , Colorado . Received June 19 , 2006 ; revision requested June 19 ; final revision received June 29 ; and accepted July 3 . Address correspondence to T.W.I.C. , c/o Tricia McClenny , Society of Interventional Radiology , 3975 Fair Ridge Dr , Suite 400 North , Fairfax , VA 22033 ; E-mail : 
    Output:
    
Conclusions Thermal ablation of small renal masses produces oncologic outcomes similar to surgical nephrectomy and is associated with significantly lower overall complication rates and a significantly less decline of renal function .