 Thank you for the opportunity to present our data here today. I have no disclosures to make. So currently despite the fact that the treatment of children and adolescents and young adults with renal tumors is extremely centralized and protocol driven through the children's oncology group, we still lack an objective way to assess the tumor complexity in those patients. Thus that makes it difficult to understand what the complexity has to do ultimately with surgical approach and outcomes. Fortunately, such a system has been identified and used in adults and you're all familiar with renal nephrometry, which has been shown as a valid instrument between users and across institutions that can understand tumor complexity and then its impact on clinical outcomes. Most pertinently for our group of patients we are interested in how does that affect the ability to safely do a partial nephrectomy and what the impact was on perioperative complications. Our thought was that such a system like renal nephrometry would be useful in a patient population of children, adolescents and young adults. And in the future, our goal would be to use it as an entry criteria for a prospective study looking at what nephron sparing surgeries role should be in these patients. But in this study to begin with, we just wanted to describe what renal nephrometry scoring looked like in a population of children, adolescents and young adults and then look at that score, how it correlated to surgical and pathologic outcomes. I won't belabor what renal nephrometry is, as I'm sure you're all familiar as opposed to when I present this talk to a group of pediatric oncologists, pediatric urologists or pediatric surgeons who are not as familiar with it. But briefly, the sum score by the authors was trichotomized into low, moderate and high complexity lesions. And we'll be using that as the way we compared our patients. Our study was a single institution retrospective review looking at all the patients who had undergone attempted or successful extirpative surgery for renal tumors between 2002 and 2013. And we excluded any patients who did not have preoperative contrast enhanced cross sectional imaging available for us to review or those who had been seen at some point in their care but did not receive their surgery at our institution. These preoperative images were reviewed by both a urologist and a radiologist familiar with renal nephrometry and any discrepancies were settled by a consensus review and a consensus score was what was used for the analysis. We then compared the tumor characteristics and outcomes between those patients with low, moderate and high complexity lesions. And this was done using nonparametric statistical analysis. Overall, we identified 65 patients who who had 67 affected kidneys in our study and the median age diagnosis of these patients was three and a half years. But you can see quite a wide variety in ages for the patients. 36 of these kidneys were imaged immediately preoperatively with CT and 31 with MRI. And in general, we're dealing with a very, very highly complex group of tumors only 7.5% were scored as low 16.4 is moderate and then 51 or 60 excuse me 76% over three quarters were highly complex lesions. I will be labor all of the individual are in a or else scores. I do want to get to some of the more pertinent facts but those will be available in the handouts to bill online. But what I wanted to get to was the interrater reliability I think as we are looking towards rolling this out in any sort of prospective fashion that would be used for entry criteria for a study, we just wanted to see how reliable was it between users and with this sort of entry criteria need to be assessed centrally or could it be done at institution institutional level. And as you can see here, the R and N scores are very reliable. At the bottom, I have what the latest published data is using nephrometry and an adult population. And while the A and L score are good, good reliability and the overall complexity is good where we really fell off was within the E score. And and I will just briefly talk about that now and bring it up again in the summary. But I think part of the problem is that when you're dealing with children with renal tumors and specifically the younger ones under the age of six or seven that have these Wilms tumor that may be a 14 centimeter lesion and a five year old that essentially replaces the whole if it's a lot of retroperitoneum. Sometimes it's difficult to assess. Well, do you call that extremely endophitic taking over the whole kidney or is that really very exophitic? And it's not explicitly enough stated such that what I thought it was versus what our radiologist thought it was was a bit different. So I think there's some nuances that would need to be changed for a particular population. As you may know, a significant minority of children and adolescents who are treated for kidney tumors get pre surgical chemotherapy. So we wanted to look at what the effect of that was on renal nephrometry scoring in this patient population. You can see here about a quarter of our patients were treated with pre surgical chemotherapy with 70% having no change in their raw score. There were almost a quarter that had a decrease. But when you then look at the actual complexity, so did they go from a high to a moderate or moderate to low or vice versa? Only 6% had a decrease in their complexity group. At the same time, one patient or 6% did have an increase during that time. So I think it's analogous to the use of TKI is we're potentially while you have an opportunity for disease, decrease in the adults with renal tumors, there's also an opportunity for disease progression in that interval. Now then when we looked at our patients and we compared those that had low complexity, moderate complexity and high complexity lesions, the first thing that jumped out to us was the difference in age. Those with the low complexity lesions were much likelier to be older and both in the moderate or high complexity lesions and this was statistically significant. There was no predilection based on sex. But in terms of the surgical approach, and this is I think what was attractive to us in the system was that the low and moderate complexity lesions were much more likely to be managed with attempted partial nephrectomy. While these numbers may not seem like much, the fact that the moderate and low complexity lesions were only approached with partial nephrectomy half or two thirds of the time, that's impressive in our minds because the gold standard by far is radical nephrectomy in children and adolescents and young adults with renal tumors almost regardless of the size. So to at least be able to tease out who the ones that could undergo partial nephrectomy was a benefit of this. Because the partial nephrectomies all went well, we were not able to use renal nephrometry to tease out the ones that had any complications from that standpoint. We were surprised though, we thought that going into this, that renal nephrometry scoring would allow us to discriminate those patients that had complications or perioperative poor outcomes, but this did not turn out to be the case. We did not see any difference in terms of the complexity and its impact on either positive margin rates, tumor spill, blood loss, transfusion requirements or operative time. Lastly and potentially the most interesting part was that we found that the scoring did correlate with the pathology and about two thirds of our patients were Wilms tumor patients. And you can see here that they make up a very highly complex group of tumors. Similarly, if you look at it from another way, most of the highly complex tumors were Wilms tumor. When you compare that then to renal cell carcinoma, which was our second most common pathology, you can see that the renal nephrometry scoring does a nice job in discriminating amongst the RCC patients specifically where about a third or low, a third or moderate, and a third or highly complex lesions. And then there is smattering of other pathologies in this group, typical of what you would find in children, clear cell sarcoma of the kidney, mesoblastic nephroma and so on. But what we did was we dichotomized this data and basically looked at RCC versus all other. And again, as I've just pointed out, it really seems that the renal nephrometry scoring does a nice job in discriminating amongst the RCC patients specifically. On the flip side, if you look at the more typical younger patients, the Wilms tumor, clear cell sarcoma, it does not seem to do very well in discriminating those patients. And so our thought was, are we really just capturing, when we look at the fact that the low complexity lesions were mostly in older patients and highly complex in the younger ones, are we just capturing with age really just the kind of tumors that occur in those patients? And so we looked at the quote unquote typical pediatric tumors, Wilms tumor, clear cell sarcoma of the kidney, congenital mesoblastic nephroma, and multilocular cystic nephroma, and compared those to the more typical adolescent tumors, things like RCC inflammatory myfrogolastic tumors, juxtaglomerular apparatus tumors. And what you can see here is again that the renal nephrometry scoring seems to be of most use in the adolescent patients, the older children. So in summary, when we looked at the clinical and pathologic features what we found were that the less complex masses were most in the older children and adolescents, they were more commonly managed with nephron sparing approaches and were more often renal cell carcinoma and non-Wilms tumor pathologies. We did not see any impact on the scoring system in terms of immediate intra and perioperative outcomes. We did encouragingly find that certain parts of the renal nephrometry score were very reliable between users and the problem with the e-square specifically I think is something that could be addressed that leads into my next point is that I think if this is going to be rolled out in a group of patients that are truly pediatric, those less than six or seven years old, I think there's going to be some further refinement that needs to be done, especially if we're looking at an entry criteria for any sort of a study, something that looks at size cutoff based on the patient's size and then maybe adding a parameter to talk about the amount of uninvolved kidney. But in general these tumors are highly complex in this patient population but as it currently stands renal nephrometry and its current iteration is probably most applicable for the adolescents and older children and those that have RCC. Ultimately it will require further refinement if it wants to be used in the more pediatric population. Thank you for your time and attention.