Three-dimensional tumour volume and cancer-specific survival for patients undergoing nephrectomy to treat pT1 clear-cell renal cell carcinoma

Rapid Segmentation of Renal Tumours to Calculate Volume Using 3D Interpolation

Small renal masses are commonly diagnosed with modern medical imaging. Renal tumour volume has been explored as a prognostic tool to help decide when intervention is needed and appears to provide additional prognostic information for smaller tumours compared with tumour diameter. However, the current method of calculating tumour volume in clinical practice uses the ellipsoid equation (π/6 × length × width × height) which is an oversimplified approach. Some research groups trace the contour of the tumour in every image slice which is impractical for clinical use. In this study, we demonstrate a method of using 3D segmentation software and the 3D interpolation method to rapidly calculate renal tumour volume in under a minute. Using this method in 27 patients that underwent radical or partial nephrectomy, we found a 10.07% mean absolute difference compared with the traditional ellipsoid method. Our segmentation volume was closer to the calculated histopathological tumour volume than the traditional method (p = 0.03) with higher Lin's concordance correlation coefficient (0.79 vs 0.72). 3D segmentation has many uses related to 3D printing and modelling and is becoming increasingly common. Calculation of tumour volume is one additional benefit it provides. Further studies on the association between segmented tumour volume and prognosis are needed.

Tumor volume: a new prognostic factor of oncological outcome of localized clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is one of the most frequent malignancies; however, the present prognostic factors was deficient. This study aims to explore whether there is a relationship between tumor volume (TV) and oncological outcomes for localized ccRCC.

METHODS

Seven hundred forty-nine localized ccRCC patients underwent surgery in our hospital. TV was outlined and calculated using a three-dimensional conformal radiotherapy planning system. We used receiver operating characteristic (ROC) curves to identified optimal cut-off value. Univariable and multivariable Cox regression models were performed to explore the association between TV and oncological outcomes. Kaplan-Meier method and log-rank test were used to estimate survival probabilities and determine the significance, respectively. Time-dependent ROC curve was utilized to assess the prognostic effect.

RESULTS

Log rank test showed that higher Fuhrman grade, advanced pT classification and higher TV were associated with shortened OS, cancer-specific survival (CSS), freedom from metastasis (FFM) and freedom from local recurrence (FFLR). multivariable analysis showed higher Fuhrman grade and higher TV were predictors of adverse OS and CSS. The AUC of TV for FFLR was 0.822. The AUC of TV (0.864) for FFM was higher than that of pT classification (0.818) and Fuhrman grade (0.803). For OS and CSS, the AUC of TV was higher than that of Fuhrman grade (0.832 vs. 0.799; 0.829 vs 0.790).

CONCLUSIONS

High TV was an independent predictor of poor CSS, OS, FFLR and FFM of localized ccRCC. Compared with pT classification and Fuhrman grade, TV could be a new and better prognostic factor of oncological outcome of localized ccRCC, which might contribute to tailored follow-up or management strategies.

Determinants and Implications of Excised Parenchymal Mass on Robotic-Assisted Partial Nephrectomy Outcomes

OBJECTIVES

To evaluate the association between excised parenchymal mass (EPM) and postoperative renal function (eGFR) following robotic-assisted partial nephrectomy (RAPN). EPM is the amount of healthy renal parenchyma excised during partial nephrectomy in order to achieve safe surgical margins.

METHODS

We evaluated 406 consecutive RAPN performed by a single surgeon to eliminate variations in technique as a factor in EPM. EPM (mL) = (specimen volume * π/6) - (tumor volume * π/6). RENAL score was categorized as easy (4-6), moderate (7-9), or hard (10-12). EPM was grouped into four categories: ≤ 3.9 mL, 4.0-9.9 mL, 10.0-17.7 mL, and >17.7 mL. eGFR was evaluated preoperatively, postoperative day 1 (POD1), 1 month, and 6 months postoperatively.

RESULTS

Median age was 63 years (22-84 years), 252 (62.1%) were male, and median EPM was 9.9 mL (interquartile range 3.9 to 17.7 mL). The median EPM and interquartile range for each RENAL category was 3.7 mL (2.0, 7.9), 12 mL (5.7, 19.4), and 16.2 mL (7.9, 24.3), respectively. Higher EPM was associated with worse changes in eGFR at POD1 (P = 0.005) and 1 month after RAPN (P = 0.002) but was not statistically significant at the 6-month time period (P = 0.35) CONCLUSION: Increased tumor complexity is associated with an increase in EPM during RAPN. Increased EPM is associated with eGFR decline at POD1 and 1 month post RAPN but not at 6 months postoperatively.

Assessment of Advanced Perioperative Outcomes to Identify the True Learning Curve of Robotic-assisted Partial Nephrectomy

OBJECTIVES

To evaluate the learning curve of robotic-assisted partial nephrectomy as it pertains to operative time (OT) and advanced perioperative variables such as achievement of trifecta, postoperative complications, 30-day readmission rates (RR), warm ischemia time (WIT), and functional volume loss (FVL).

METHODS

We evaluated 418 consecutive robotic-assisted partial nephrectomy performed by a single surgeon between February 2008 and April 2019. Multivariable log-log regression models were used to evaluate the associations between case number and continuous outcomes (OT, WIT, and FVL). Multivariable logistic regression models were used to evaluate the association of case number with dichotomous outcomes (trifecta, postoperative complications, RR).

RESULTS

Among the 406 eligible patients included in the study, 252 (62.1%) were male, median age was 63 years (range, 22-84), and median body mass index was 29 kg/m² (interquartile range 26-33). Surgeon experience was associated with shorter OT (-2.5% per 50% increase in case number; 95% confidence interval; P <.001) and plateaus around 77 cases performed. There was slight improvement with trifecta (odds ratio [per 50% increase in cases] = 1.08; 95% confidence interval) and the plateau was also at 77 cases, however, this was not statistically significant (P = .086). We did not find statistically significant associations of surgeon experience with FVL (P = .77), postoperative complications (P = .74), WIT (P = .73), or 30-day RR (P = .33).

CONCLUSION

There does not appear to be a relationship between surgical experience and grade 3 or higher postoperative complications, 30-day RR, WIT, or FVL. Trifecta outcomes and maximum OT performance appear to be optimized at approximately 77 cases.

Volumetric analysis at abdominal CT: oncologic and non-oncologic applications

Volumetric analysis is an objective three-dimensional assessment of a lesion or organ that may more accurately depict the burden of complex objects compared to traditional linear size measurement. Small changes in linear size are amplified by corresponding changes in volume, which could have significant clinical implications. Though early methods of calculating volumes were time-consuming and laborious, multiple software platforms are now available with varying degrees of user-software interaction ranging from manual to fully automated. For the assessment of primary malignancy and metastatic disease, volumetric measurements have shown utility in the evaluation of disease burden prior to and following therapy in a variety of cancers. Additionally, volume can be useful in treatment planning prior to resection or locoregional therapies, particularly for hepatic tumours. The utility of CT volumetry in a wide spectrum of non-oncologic pathology has also been described. While clear advantages exist in certain applications, some data have shown that volume is not always the superior method of size assessment and the associated labor intensity may not be worthwhile. Further, lack of uniformity among software platforms is a challenge to widespread implementation. This review will discuss CT volumetry and its potential oncologic and non-oncologic applications in abdominal imaging, as well as advantages and limitations to this quantitative technique.

Prognostic influence of 3-dimensional tumor volume on breast cancer compared to conventional 1-dimensional tumor size

Purpose

The prognostic influence of 3-dimensional tumor volume (Tv) on breast cancer compared to conventional 1-dimensional tumor size (T) was investigated.

Methods

Analysis was performed on a cohort of 8,996 primary breast cancer patients who were initially diagnosed with TNM stage I–III. Tumor size was defined as the maximum tumor dimension, and Tv was calculated by the equation of (4π × r1 × r2 × r3)/3; r1, r2, and r3 were defined as half of the largest, intermediate, and shortest dimension of the tumor, respectively. Tv was classified into Tv1, Tv2, and Tv3 according to the cut off values of 2.056 cm³ and 20.733 cm³.

Results

The survival curves according to both the T and Tv categories were clearly differentiated (all P < 0.001), as were those for staging by T and Tv (all P < 0.001). In T1 and T2 tumors, the Tv1 group showed superior survival over the Tv2 group (T1, P < 0.001; T2, P = 0.001). Univariate and multivariate analysis both indicated that Tv was a significant prognostic factor (both P < 0.001). The receiver operating characteristic curve showed that the area under the curves were 0.712 (P < 0.001) for Tv and 0.699 (P < 0.001) for T. Positive correlations were observed between the number of positive nodes and T (coefficient = 0.325; P < 0.001), and between the number of positive nodes and Tv (coefficient = 0.321; P < 0.001).

Conclusion

Tv classification works well for predicting the prognosis of breast cancer, and it is a better predictor than conventional T classification in several aspects. Further studies are needed to validate the practical usefulness of Tv classification in clinical settings.

Volume and Shape Assessment of Renal Radiofrequency Ablation Lesion

OBJECTIVE

To evaluate the microscopic characteristics and quantify the volume of a radiofrequency ablation (RFA) lesion.

METHODS

Ten male pigs were submitted to laparoscopic RFA. An RFA needle was introduced in the lower pole of the left kidney to create a lesion expected to be a sphere of 2.0 cm diameter. The animals were followed up for 21 days. Kidneys were weighed and the volume was assessed using Scherle's method. Cavalieri's principle was used to assess the RFA volume, and sphericity was calculated to assess RFA lesion. One sample t test was used to compare RFA volume with the volume of a sphere of 2.0 cm diameter, and sphericity to hypothetical values of a sphere and an icosahedron. Fragments of RFA region were histologically evaluated.

RESULTS

Three animals developed postoperative complications and were excluded from the analyses. There was no difference in the mean weight and volume between right and left kidneys following RFA. The mean total volume of RFA injury was 3.44 cm³. There was no difference in the RFA volume in comparison with hypothetical volumes of a sphere and an icosahedron of 2.0 cm diameter. Sphericity of the RFA injury was not similar with a sphere; however, it was similar to an icosahedron. Histology revealed areas of coagulation necrosis, fibrosis, and inflammatory mononuclear infiltration. Areas with normal tissue were also observed.

CONCLUSION

The volume of injury caused by RFA was as expected and its shape was comparable with an icosahedron. Microscopic evaluation revealed areas of normal-appearing tissue.

Selective arterial clamping does not improve outcomes in robot-assisted partial nephrectomy: a propensity-score analysis of patients without impaired renal function

OBJECTIVES

To assess the benefit of selective arterial clamping (SAC) as an alternative to main renal artery clamping (MAC) during robot-assisted partial nephrectomy (RAPN) in patients without underlying chronic kidney disease (CKD).

PATIENTS AND METHODS

Our study cohort comprised 665 patients without impaired renal function undergoing MAC (n = 589) or SAC (n = 76) during RAPN from four medical institutions in the period 2008-2015. We compared complication rates, positive surgical margin (PSM) rates, and peri-operative and intermediate-term renal functional outcome between 132 patients undergoing MAC and 66 undergoing SAC after 2-to-1 nearest-neighbour propensity-score matching for age, sex, body mass index, RENAL nephrometry score, tumour size, baseline estimated glomerular filtration rate (eGFR), American Society of Anesthesiologists (ASA) score, Charlson comorbidity index (CCI) and warm ischaemia time (WIT).

RESULTS

In propensity-score-matched patients, PSM (5.7 vs 3.0%; P = 0.407) and complication rates (13.8 vs 10.6%; P = 0.727) did not differ between the MAC and SAC groups. The incidence of acute kidney injury for MAC vs SAC (25.0 vs 32.0%; P = 0.315) within the first 30 days was similar. At a median follow-up of 7.5 months, the percentage reduction in eGFR (-9.3 vs -10.4%; P = 0.518) and progression to CKD ≥ stage 3 (7.2 vs 8.5%; P = 0.792) showed no difference.

CONCLUSIONS

Our study findings show no difference in PSM rates, complication rates or intermediate-term renal functional outcomes between patients with unimpaired renal function who underwent SAC vs those who underwent MAC. When expected WIT is low, the routine use of SAC may not be necessary. Further studies will need to determine the role of SAC in patients with a solitary kidney or with significantly impaired renal function.

Efficacy of primary tumour volume as a predictor of survival compared with size alone in pancreatic ductal adenocarcinoma

Tumour size (TSize) predicts outcome in pancreatic ductal adenocarcinoma (PDAC), but little is known regarding three-dimensional tumour volume (TVol) associations. We hypothesised that TVol would more accurately predict outcome following pancreatoduodenectomy (PD) for PDAC. Clinicopathological and outcome data was reviewed for all PDs performed in the Royal North Shore Hospital (St. Leonards, NSW, Australia), between April 2004 and November 2010, in patients whose three tumour dimensions were recorded (n=103). TVol was quantified using the ellipsoidal volume formula, 4/3π(r1×r2×r3), and was correlated with clinicopathological indices/outcome. Over a median follow-up time of 20.5 months, TVol failed to significantly predict post-resection mortality [odds ratio (OR), 1.0; 95% confidence interval (CI), 0.99-1.00; P=0.438)]. Neural invasion remained an overall independent predictor of mortality following multivariate analysis (OR, 3.94; 95% CI, 1.36-11.40; P=0.011). Patients with higher TVol were more likely to require a vascular resection (P=0.007), had longer surgical times (P<0.001), larger intraoperative blood losses (P=0.007) and a trend toward worse survival (P=0.068). TVol inclusion in a multivariate model resulted in a small improvement in mortality prediction versus TSize (14.9 vs. 14.7%). A higher TVol results in a more complex perioperative course. Although TVol improved the mortality prediction beyond simple TSize alone, this difference was not significant. Studies normalising TVol for body composition are required.

The impact of three-dimensional tumor volume on cancer-specific survival for patients with pT1 clear-cell renal cell carcinoma

PURPOSE

To evaluate the impact of three-dimensional tumor volume on cancer-specific survival for patients with pT1 clear-cell renal cell carcinoma (ccRCC).

MATERIALS AND METHODS

We reviewed a prospectively maintained database of 917 patients who underwent radical nephrectomy or nephron-sparing surgery for unilateral, pT1 ccRCC, including 654 pT1a and 263 pT1b patients, between April 1997 and December 2010. Three-dimensional tumor volume was measured using specialized volumetric software on cross-sectional computed tomography images of a preoperative venous phase. Kaplan-Meier and Cox regression analyses were carried out.

RESULTS

The median age was 54 years with a follow-up of 60.8 months. Median tumor size and volume were 3.2 cm and 17.4 cm(3), respectively. Of 917 patients, 54 (5.9 %) had died, including 32 patients with ccRCC (9 patients in pT1a and 23 patients in pT1b). On multivariate analysis, tumor size >3.2 cm and tumor volume >17.4 cm(3) were associated with cancer-specific death in pT1 ccRCC patients. When stratified by pT1a/pT1b status and analyzed on median splits, tumor size >2.5 cm was associated with cancer-specific death but not tumor volume >9.5 cm(3) in pT1a patients. However, in pT1b patients, tumor volume >62.1 cm(3) (P = 0.036, HR 2.91, 95 % CI 1.02-7.77) was highly associated with cancer-specific death but not tumor size >5.0 cm (P = 0.159, HR 1.91, 95 % CI 0.78-4.70).

CONCLUSIONS

In addition to tumor size, tumor volume is associated with cancer-specific death in pT1 ccRCC patients, particularly in pT1b ccRCC but not in pT1a ccRCC.

A comparison of radiologic tumor volume and pathologic tumor volume in renal cell carcinoma (RCC)

OBJECTIVE

To investigate the difference between preoperative radiologic tumor volume (RTV) and postoperative pathologic tumor volume (PTV) in patients who received nephrectomy for renal cell carcinoma (RCC).

MATERIALS AND METHODS

We reviewed 482 patients who underwent preoperative computed tomography (CT) within 4 weeks before radical or partial nephrectomy for renal cell carcinoma. RTV measured by a three dimensional rendering program was compared with PTV (π/6 x height x length x width) measured in surgical specimen according to pathologic tumor size and histologic subtype. Correlation of the inter-quartile range (IQR) of the RTV and Fuhrman nuclear grade was also investigated.

RESULTS

There was a significant positive linear correlation between RTV and PTV (p < 0.001, r = 0.911), and the mean RTV and mean PTV were not significantly different (79.0 vs 76.9 cm3, p = 0.393). For pathologic tumor size (PTS) < 4 cm, the mean RTV was larger than the mean PTV (10.9 vs 7.1 cm3, p < 0.001). For a PTS of 4-7 cm, the mean RTV was larger than the mean PTV (56.0 vs 44.7 cm3, p < 0.001). However, for a PTS ≥ 7 cm, there was no statistical difference between RTV and PTV (p > 0.05). Among patients with clear cell RCC, the mean RTV was significantly larger than the mean PTV (p = 0.042), not for non-clear cell group (p = 0.055). As the quartile of the RTV increased, the Fuhrman grade also increased (p < 0.001).

CONCLUSIONS

RTV was correlated with PTV and pathologic grade. RTV was larger than the PTV for a tumor size 7 cm or less or in clear cell RCC. RTV may be useful to measure tumor burden preoperatively.

The Zhongshan score: a novel and simple anatomic classification system to predict perioperative outcomes of nephron-sparing surgery

In the zero ischemia era of nephron-sparing surgery (NSS), a new anatomic classification system (ACS) is needed to adjust to these new surgical techniques. We devised a novel and simple ACS, and compared it with the RENAL and PADUA scores to predict the risk of NSS outcomes. We retrospectively evaluated 789 patients who underwent NSS with available imaging between January 2007 and July 2014. Demographic and clinical data were assessed. The Zhongshan (ZS) score consisted of three parameters. RENAL, PADUA, and ZS scores are divided into three groups, that is, high, moderate, and low scores. For operative time (OT), significant differences were seen between any two groups of ZS score and PADUA score (all P < 0.05). For ZS score, patients with moderate and high scores had longer warm ischemia time (WIT) and greater increase in SCr compared with low score (all P < 0.05). What is more, the differences between moderate and high scores classified by ZS score were borderline but trending toward significance in WIT (P = 0.064) and increase in SCr (P = 0.052). Interestingly, RENAL showed no significant difference between moderate and high complexity in OT, WIT, estimated blood loss, and increase in SCr. Compared with patients with a low score of ZS, those with a high or moderate score had 8.1-fold or 3.3-fold higher risk of surgical complications, respectively (all P < 0.05). As for RENAL score, patients with a high or moderate score had 5.7-fold or 1.9-fold higher risk of surgical complications, respectively (all P < 0.05). Patients with a high or moderate score of PADUA had 2.3-fold or 2.8-fold higher risk of surgical complications, respectively (all P < 0.05). In the ROC curve analysis, ZS score had the greatest AUC for surgical complications (AUC = 0.632) and the conversion to radical nephrectomy (AUC = 0.845) (all P < 0.05). In conclusion, the ability of ZS score to predict the surgical complexity and surgical complications of NSS is better than RENAL and PADUA scores. ZS score could be used to reflect the surgical complexity and predict the risk of surgical complications in patients undergoing NSS.

Increasing volume of non-neoplastic parenchyma in partial nephrectomy specimens is associated with chronic kidney disease upstaging

INTRODUCTION

We examined the effect of non-neoplastic parenchymal volumes (NNPVs) in partial nephrectomy (PN) surgical specimens on long-term postoperative renal function. PN for renal cortical neoplasms has demonstrated superior long-term renal function outcomes compared with radical nephrectomy. Minimizing the distance between the surgical margin and tumor will reduce the NNPV removed. The role of NNPV on postoperative outcomes has been preliminarily investigated, with varying results. Thus, we sought to determine the association between the NNPV removed and postoperative chronic kidney disease (CKD) staging.

MATERIALS AND METHODS

Our institutional database was queried for patients who had undergone PN from 1990 to 2012. The demographic and pathologic data were collected. The ellipsoid formula was used to calculate the surgical specimen and tumor volumes, which were then subtracted from each other to determine the NNPV. The estimated glomerular filtration rate (eGFR) was calculated using the Modification of Diet in Renal Disease formula. Binary logistic regression analysis was used to determine the predictors of postoperative CKD upstaging according to the eGFR.

RESULTS

A total of 584 patients meeting the inclusion criteria had undergone PN. On binary logistic regression analysis, controlling for age, tumor volume, surgical modality, and preoperative CKD stage, an increasing NNPV in the surgical specimen was independently associated with postoperative CKD upstaging (odds ratio, 1.004; P = .007).

CONCLUSION

An increasing NNPV removed during PN correlated with CKD upstaging using the eGFR; therefore, additional emphasis should be placed on healthy parenchymal preservation, with long-term follow-up to ensure adequate oncologic outcomes.

The current status of tailor-made medicine with molecular biomarkers for patients with clear cell renal cell carcinoma

Appropriate use of multiple reliable molecular biomarkers in the right context will play a role in tailormade medicine of clear cell renal cell carcinoma (RCC) patients in the future. A total of 11,056 patients from 53 studies were included in this review. The article numbers of the each evidence levels, using the grading system defined by the Oxford Centre for Evidence-based Medicine, in 1b, 2a, 2b, and 3b were 5 (9%), 18 (34%), 29 (55%), and 1 (2%), respectively. The main goal of using biomarkers is to refine predictions of tumor progression, pharmacotherapy responsiveness, and cancer-specific and/or overall survival. Currently, carbonic anhydrase (CA9) and vascular endothelial growth factor (VEGF) in peripheral blood and p53 in tumor tissues are measured to predict metastasis, while VEGF-related proteins in peripheral blood are used to assess pharmacotherapy responsiveness with sunitinib. Furthermore, interleukin 8, osteopontin, hepatocyte growth factor, and tissue inhibitors of metalloproteinases-1 in peripheral blood enable assessment of responsiveness to pazopanib treatment. Other reliable molecular biomarkers include von Hippel–Lindau gene alteration, hypoxia-inducible factor-1a, CA9, and survivin in tumor tissues and VEGF in peripheral blood for predicting cancer-specific survival. In the future, studies should undergo external validation for developing tailored management of clear cell RCC with molecular biomarkers, since individual institutional studies lack the generalization and consistency required to maintain accuracy among different patient series.

Kidney volume correlates with tumor diameter in renal cell carcinoma and is associated with histological poor prognostic features

We aimed to correlate kidney volume (KV) in renal cell carcinoma nephrectomy specimens with tumor diameter (TD), macroscopic growth pattern, and histological features associated with poor prognosis. Histopathology reports, macroscopic specimen photographs, and selected glass slides were retrospectively reviewed. KV was approximated to the volume of an ellipsoid. A total of 273 specimens were identified with median KV 245 cm(3). Kidneys larger than this contained larger tumors (7.5 vs 4.5 cm). KV was significantly greater in tumors of high grade, involving perinephric fat, exhibiting venous invasion, and involving renal sinus. There was a robust linear correlation between KV and TD (r = 0.602) and a weaker correlation between kidney diameter (KD) and TD (r = 0.53). In pT1 tumors, KV (r = 0.40) also correlated better with TD than did KD (r = 0.27). By multiple regression analysis, both TD and venous invasion independently predicted both KD (R (2) = 38.27%) and KV (R (2) = 51.97%). KV and KD correlate well with TD and histopathological features of aggressiveness, although KD correlates better overall and in the pT1 subset.

Preoperative decision making for renal cell carcinoma: cystic morphology in cross-sectional imaging might predict lower malignant potential

OBJECTIVES

Several histologic studies showed more favorable oncologic outcome for renal cell carcinoma (RCC) with cystic change. However, there is no prognostic tool to judge on cystic RCC preoperatively. We hypothesized, that cystic morphology in cross-sectional imaging predicts lower malignant potential.

MATERIALS AND METHODS

From our prospectively conducted oncologic database, we identified 825 patients who underwent surgery for malignant renal tumors between 2001 and 2010. In 348 cases (42%), adequate imaging was available for an independent review by 2 radiologists. We excluded recurrent and synchronous bilateral RCC, familial syndromes, collecting duct carcinoma, and metastases of other origin. For the resulting 319 patients, we compared clinical, pathologic, and survival outcomes.

RESULTS

Median age was 63 (19-88) years and 220 (69%) patients were male. Median follow-up was 1.7 (0-9.8) years. Of 319 renal masses, 277 (86.8%) were solid and 42 (13.2%) were cystic. In cystic RCC, median tumor diameter was lower (3 cm vs. 4 cm, P = 0.002) and nephron-sparing surgery was more frequent (69% vs. 41.5%, P = 0.002). None of the patients with cystic RCC and 56 (20.2%) with solid RCC had synchronous systemic disease (P = 0.001). The nuclear grade of cystic RCC was more favorable (P = 0.002). Patients with cystic RCC showed better overall (P = 0.049) and cancer-specific survival (P = 0.027). In a multivariate model, only synchronous metastases, positive R status, and greater tumor diameter were independent risk factors (P ≤ 0.03).

CONCLUSIONS

We report the first study to show that cystic morphology in cross-sectional imaging might predict RCC with a lower malignant potential. This insight could allow less invasive treatment strategies in selected patients.