 I've taken the liberty of changing the title slightly to say, should renal mass biopsy be performed routinely? And my answer would be no. Conflict of interest, I have none, although I would tell you that I do order some renal mass biopsies in my patients. So if we look at the AUA guidelines for renal cell carcinoma, and these are presented frequently, and we usually focus on the lower boxes in terms of treatment options, but actually in that upper evaluation box it says something pretty interesting, which is a good place to start and probably a good place to finish our talk as well, which is that percutaneous renal mass biopsy for patients in whom it might impact management, particularly patients with clinical or radiographic findings suggestive of lymphoma, abscess, or metastasis, that's what's recommended. So it's recommended when it may impact management. So what about historically and what about today? Is that how it's being used? Well, renal mass biopsy has not been used routinely. For three main concerns. First is the fear of tumor seeding, which Dr. Krutikov mentioned already, and I would reiterate is unfounded concern. This is not a dangerous procedure for patients. Secondly is the undesirable rate of finding indeterminate or inaccurate diagnosis, and I'll touch on that more in a few minutes. The third is that 80% of renal masses are cancer anyway. It's not going to change what I do, so why should I get a biopsy? And that, again, has been the mantra for many years. Nevertheless, I will assert that renal mass biopsy is clearly the correct diagnostic step in some patients, as indicated in the guidelines, and sort of blast biopsy completely would be a poor position to take. So how have we been doing now in the 21st century? Well, our group released a review article several years ago comparing results from 2001 to 2005 with results obtained previously, and clearly there were some improvements. So there's increased accuracy for cancer that's seen for these studies up to about 96%. But, again, the total success rate's about 91% better than had been reported previously at about 81%. An update to this, which, again, reviewed the literature for the last five years or for the next five years, revealed similar findings. Again, about a 95% accuracy rate. But, again, we really need to think about this a little more clearly. What does that mean? I mean, are we talking about if it's cancer? Is it really cancer? Or are we talking about the biopsy giving you a result that you need? And if you look through all of these results, they may term them differently, but biopsy failures or indeterminate biopsies or non-informative biopsies are as high as 29% in some series. And so caveats about these accuracy claims would be, it's true that it's 1% or less biopsies that are wrong. So false positives, false negatives. The majority are infirmative and confirmed to be true. But if you look at the literature, a lot of them are informative and presumed true. There's no actual pathologic confirmation on the biopsy that's obtained. The bigger concern is the 10% to 20% that remain non-informative. And those could be failed either because tissue was not obtained or the pathologist couldn't make the definitive diagnosis. As Dr. Kudakov mentioned, you have options here. You can do a repeat biopsy. And Dr. Jewett's group and others have shown that that is a successful strategy. Or you can just treat them as though they have cancer. So with all this encouraging thought about renal mass biopsy, several groups have decided that routine biopsy is the way to go. And so here's a series from Dr. Jewett's group published in 2011. And reading from their paper, it said, our policy has been to recommend biopsy for all. Small renal mass is less than three centimeters. And to discuss the role of biopsy for patients three to four. Well, what were their results? So again, about 80% were diagnostic. Among those, you can see that about 80% were malignant. Most were RCC. And you could get a subtype on close to 90%. But importantly, there were 67 non-diagnostic biopsies and 12 of those patients underwent a repeat biopsy. The author's conclusions, renal mass biopsy is safe. It's accurate. A non-diagnostic biopsy is not a surrogate for the absence of cancer. Rather, repeat biopsy can be performed with similar accuracy. I'd say alternative conclusions would be number one. Two out of 10 patients underwent a non-informative biopsy. And although the repeat biopsy found cancer in eight of the 12 patients who had one, fewer than 20% of those patients were willing to have a second biopsy or the provider was not willing to do another one. What's missing from this report is how often are treatment plans changed because of the biopsy and how many more kidneys may have been spared based on this approach. So I'd really ask us to go back to what's the question we're asking. I mean, what's the goal of this biopsy? I think our goal is to better match treatment to the biology expressed by the tumor. And that's very compelling. But are we really doing that? And how exactly would that happen? So first of all, are we reducing the overall morbidity to our patients of this diagnostic and therapeutic paradigm? We're adding a biopsy for 100 patients to avoid surgery for five to 10. We're identifying and risk-assessing cancer or lack of cancer without performing an operation. Is that the goal? Again, I think it's a laudable goal. But 80 to 85% of the biopsies are diagnostic. We talked about the indeterminate rate. And then the grading is very unreliable. And so again, if we're talking about those man-eaters versus the other sharks, biopsy is not doing it for you. Next goal could be to prevent the removal of kidneys lacking cancer. And I think that's where a lot of us are concerned and public health concerns about taking out the whole kidney for a 3-centimeter oncocytoma. But is that really happening? 15% of surgeries that have no cancer or 15% of the surgeries done presently have no cancer, but the vast majority are nephron-sparing techniques. And so finally, are we really going to reduce over treatment of kidney cancer by doing biopsy? I don't think that's the issue. I think the issue is sparing kidneys. So let's look at another group that has pursued routine biopsy. And this is the group at Michigan. And I apologize. I put my conclusions on top of those right away. But they performed a biopsy 38% of the time. And if you'll see actually in the bottom, if they compared the group that got biopsy versus didn't, active surveillance did increase. So five more percent of patients were surveilled, but actually radical nephrectomy increased dramatically from 8% to 21%. So again, was this used uniformly when their intention was to do it? No. Did it increase surveillance? Sure. But it also increased radical nephrectomy. So if those were the goals we just discussed, these are the conclusions we could draw from another group's experience with routine biopsy. We may be better matching treatment to biology. It's unclear whether we're reducing morbidity from what I can tell from the report. We are identifying cancer without surgery. Maybe we're preventing the removal of kidneys that lack cancer. But really, we did not reduce the number of nephrectomies. We increased them. So further support for the decision not to perform a biopsy is from Dr. Kudakov himself. And this is a preoperative nomogram looking at whether we can predict the features of the cancer prior to surgery. And so if you look at examples here, and I apologize it's somewhat small, but the top gentleman, for example, who's 50, has a large tumor. It's exophitic. You have the nephrometry score listed. 99% of cancer. So my question is why would you biopsy a patient with a 99% chance of cancer based on your preoperative suspicion? What gain will we have there? So final point would be about practicality. At most centers, the logistics of coordinating arenal mass biopsy necessitate a further delay in treatment. Usually it requires scheduling with interventional radiology. They may not like the initial CT scan. They may not like the ultrasound. They may need another study before they do the biopsy. The pathology may or may not be as other centers would have come to expect in 2013 in terms of sub-specialty pathology availability. So it may need to get sent out. You may need to do initial appointment in almost all these patients to rediscuss options. And so you're introducing a delay. Some of these concerns could certainly be addressed by an in-office procedure. But this is not routinely available. Here's some images from an in-press article from Dr. Landman's group where they're actually now performing these in the office. And I think that could be a good step for the future. So what I would leave you with is will a renal mass biopsy really affect the treatment recommendation you'd make for a 50-year-old with an 80-metre renal mass or a 50-year-old with a 4-centimeter renal mass or an 80-year-old sick patient with a 2.5-centimeter rest? I mean, those patients, I pretty much have already decided what I'm doing right now. And you probably have as well if you see these patients. A lab nephrectomy, a partial, or surveillance with short follow-up imaging to rule out interval growth without a biopsy in that older patient. So I would not use a biopsy for all patients, but maybe for this gentleman at the bottom. He's got multiple comorbidities and a completely intraprankable tumor. He actually is the third patient on this list, and he was biopsy found to have amnesia in his tubular spindle cell carcinoma and therefore is being managed with surveillance. But other personal experiences you see above, I had a young gentleman with a history of TB who wanted to rule out renal TB. He had a bleed and delayed his surgery. There's a 36-year-old with what turns out to be a cancer delayed unnecessarily because of a biopsy. I have another patient who I didn't want to do surgery on. He's once get listed for a transplant, but the biopsy again didn't help me a lot here with an oncocytic renal neoplasm. So my experience is, as a frequent performer of these tests, is I only use it sporadically during the last five years. I only performed a radical nephrectomy four times for benign disease, and if you look at how that happened, one's a patient with a known and large symptomatic AML. Two are patients on dialysis, and one's a tumor with a tumor thrombus that was on necrotic when it came out. So I don't think in this paradigm we're removing kidneys unnecessarily. So in conclusion, R&B should be performed only when it will affect management of a suspected renal mass. It's not always necessary. As the results of renal mass biopsy will not change management in many situations and only rarely change management in others. And again, it's not without cost. Thanks for your time.