Patient, tumor factors dictate partial vs. radical nephrectomy

In patients with localized kidney cancer, treatment has evolved with the utilization of minimally invasive surgery. In this interview, Chandru P. Sundaram, MD, explains the important patient and tumor characteristics to consider in deciding between partial and radical nephrectomy. Dr. Sundaram also discusses surgical planning, complications of both approaches, and pathologic examination.

Dr. Sundaram is director of minimally invasive surgery, program director, and professor of urology, Indiana University Medical Center, Indianapolis. He was interviewed by Urology Times Editorial Consultant J. Brantley Thrasher, MD, executive director of the American Board of Urology, Charlottesville, VA.

Please start by explaining patient selection for partial versus radical nephrectomy and why you might choose one over the other.

It’s all about individualizing treatment to the patient and to the tumor as well. You have to put together tumor characteristics and patient characteristics and then decide whether partial or radical is better for that individual patient. There are several aspects of both the tumor and the patient that need to be looked at.

Do you feel that doing a biopsy makes a difference in that surgical plan?

There is a huge range of practice with regard to biopsies in an individual patient. In my practice, the question I ask myself with each patient is, will biopsy make a difference to my management? If it does, then I do it. With that principle in mind, I would say about one-fourth of my patients end up getting a biopsy.

What other factors are important in the surgical planning?

Let’s talk about the patient first-the patient’s renal function, comorbidities, age, body habitus, and past surgeries. The individual surgeon’s training and experience also need to be considered. All these would make a difference in what surgery you do and what approach you take.

Let’s consider a patient with a tumor that’s not hilar, and it’s exophytic. Would you generally choose partial over radical nephrectomy most of the time, and why?

For a T1a tumor, my default surgical approach, assuming the patient is a surgical candidate, would be a partial nephrectomy. Then I would ask, are there any factors in this patient or this tumor that would prevent me from doing a partial safely? If the answer is yes, then I would explore other options: Would radical nephrectomy be better? Would percutaneous cryoablation be better? Or, most importantly, would active surveillance or watchful waiting be better? All these questions have to be taken into consideration in every patient.

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I would definitely do a partial versus radical nephrectomy in a patient whose expected glomerular filtration rate after radical nephrectomy is expected to be less than 45; a patient with a solitary kidney; a patient with multiple risk factors such as hypertension and diabetes; or a patient with other anomalies that would result in high risk for chronic kidney disease in the future. 

Which patients would you exclude from partial nephrectomy?

I would exclude patients in whom I think doing a partial would really not result in significant nephron sparing-for instance, those with a small kidney and a large tumor. In a patient with a normal contralateral kidney with multiple comorbidities, I have to get this patient off the table as soon as I can. The risk of increased complications may be much higher with the partial nephrectomy when there is a high nephrometry score.

Again, patient characteristics and tumor characteristics are important, and a third component to this treatment decision-making is the surgeon’s experience and capabilities. Those are very important and need to be addressed based on the surgeon’s past experience. It’s important that you look back at your patient outcomes after partial nephrectomy.

Next: Is there a particular position on the kidney that would make surgery a little more difficult laparoscopically or robotically?Is there a particular position on the kidney that would make surgery a little more difficult laparoscopically or robotically?

Yes. It all depends on which approach you use. If you’re doing a transperitoneal approach, an upper pole posterior tumor would be difficult, especially in a morbidly obese man with sticky fat around the kidney. Those are all risk factors that would make it technically challenging.

In which cases are the risk of post-op complications higher?

For large tumors with high nephrometry score, there clearly is an increased risk of urologic complications. However, with the utilization of robotics, that difference has decreased considerably.

What are the major complications associated with partial nephrectomy that you generally would not see with a radical?

Bleeding and urine leak are the two most important urologic complications where it makes a difference between partial and radical. However, with the robotic approach by an experienced surgeon, the risk of urologic complications should be less than 5%.

Do you drain all of these?

No. I drain about 25% of them-usually with complex partial nephrectomies and when a formal two-layer renorrhaphy was not used. 

If you’ve gotten into the collecting system, are you going to drain? 

Actually, no. It’s all a matter of how you progress in practice. When I started doing partial nephrectomies, half of these surgeries were actually open. As time went by, I became more and more comfortable with the robotic approach, and now virtually all of my partials are robotic. I probably do one or two open partial nephrectomies a year; like patients with two previous partial nephrectomies when there is a recurrence. Those are the kind of patients you may consider for an open approach, but the robotic approach is the go-to procedure right now in my armamentarium.

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As far as a drain is concerned, I used to drain all my patients, just like we would drain all robotic prostatectomies when we started doing them. We no longer drain robotic prostatectomies. Similarly with robotic partial nephrectomies, with an about 1% incidence of a urine leak in my practice, drains are not required in most patients.

Is there a tumor size maximum that will prevent you from doing a partial, or is it based on position?

It depends on position. In fact, the largest partial I’ve done was 10 cm, but it was hanging off the lower pole and was very exophytic. The rest of the kidney was completely normal. As it turned out, this was a low-grade tumor, and I’m glad we did a partial nephrectomy on that patient.

In terms of outcomes for partial versus radical, are cancer-specific survival and overall survival better in one than the other?

The only randomized trial showed equivalence with both approaches. There was a recent, large observational report from Mayo Clinic that suggested there was no difference in overall survival between the two groups after adjusting for a wide range of co-variates. But certainly there is an increase in chronic kidney disease after a radical versus a partial.

In the case of partial nephrectomy, do you always send yours down at the time of the operation for frozen section to look at the margin?

Frozen section pathology during robotic partial nephrectomy is rarely required. However, ensuring a grossly negative margin is critical and usually possible with the magnification of robotic surgery, especially with a bloodless field due to renal vascular control.

If that frozen section came back positive, would you take another margin?

I’ve done that maybe three or four times-about one in 100 partials. I think the best shot is the first shot at doing this procedure because once you put the kidney back together, reclamping the hilum and taking down the reconstruction is difficult. However, recognizing a positive margin during tumor excision and revising the excision or excising another slice of the tumor bed before staring the renorrhaphy may be required occasionally. 

There have been publications in which a laser has been used for a close margin or a possible focal margin. Have you used a laser in a case like that?

First, there have been many publications showing that a small positive margin doesn’t make a difference. Having said that, your goal is to have a negative margin no matter what. This is a cancer operation, and that’s what you should do. As far as the laser is concerned, you can use argon beam coagulation or even bipolar diathermy. I don’t think the laser itself makes a difference.

But I think the best way to treat a positive margin intraoperatively is to excise it. If the positive margin is diagnosed on post-op pathology, the patient can be observed with radiologic surveillance in most cases, especially if the positive margin is focal.

Next: What do you use for coagulation?What do you use for coagulation? Do you use pledgets or a gel foam in the middle of the tumor? Do you generally coagulate the cortical aspects?

Again, the technique has evolved. When I started off, I would use bolsters and a hemostatic agent in every patient. Now, I do not use bolsters and occasionally use hemostatic agents. If you do a two-layer renorrhaphy and do a good job of bringing the cortical edges together, argon beam coagulation or hemostatic agents are not required.

Having said that, there are certain special circumstances when you need to use these techniques, for example, if you are not doing a two-layer renorrhaphy or with enucleation or multiple renal masses without getting vascular control. Cost has to be considered for every disposable you use, especially when it is of questionable benefit.

What are the differences in chronic renal disease after partial and radical nephrectomy and why might you choose one or the other?

There is a distinction between medical chronic renal disease and surgical chronic renal disease. In the old landmark studies, which prompted everyone to go toward partial nephrectomy, there was a significantly higher risk of cardiovascular events in patients with chronic kidney disease. Then, after large studies primarily from Cleveland Clinic, there was a realization that medical chronic renal disease patients fared much worse over the long term than surgical chronic kidney disease patients. That makes sense because they don’t all have the comorbidities that medical patients have: no hypertension or diabetes, for example. But a surgical patient could have those as well.

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You have to be cognizant that not all chronic kidney diseases are the same, even after partial nephrectomy. These pre-existing comorbidities that can result in medical chronic kidney disease are important. But the bottom line is, there is a difference between medical chronic kidney disease, which continues to progress at a much higher rate than a surgical chronic disease.

A lot of surgeons still do a primary enucleation, especially for some of the small lesions. Would that be your practice, or are you working with scissors almost exclusively?

I don’t do enucleation as a standard. I would use enucleation in some cases where every nephron matters and you want to preserve as much renal function as possible. I would also use it in patients with hereditary renal cancer syndromes where there are multiple tumors in the kidneys. Those are the two instances where I would use enucleation.

We also have preliminary data to suggest that renorrhaphy techniques can affect post-op ipsilateral renal volume and function. Techniques to minimize loss of renal function during partial nephrectomy include restricting renal hilar clamping to less than about 20 minutes, enucleation, and excision of minimal normal renal tissue surrounding the tumor. Omitting the second layer of renorrhaphy can be utilized in selected patients. Off-clamp partial nephrectomy has also been described, though a bloodless field with clamping is preferable in most patients.

Let’s talk about the preoperative preparation for partial nephrectomy. You mentioned the situation of a tumor close to the hilum and the likelihood of a large defect growing into the collecting system. Is there anything else you would do for these larger complex tumors in preparation for surgery?

For complex surgeries, having blood in the room is important. Putting in a retrograde ureteral catheter can help in an occasional patient with a complex hilar tumor to visualize the renal pelvis and collecting system. Preoperative examination of the CT scan is very important. And in complex patients, including those with a horseshoe kidney, I would obtain a CT angiogram to visualize the secondary arteries close to the tumor. 3-D reconstruction and models are being used for preoperative planning. A recent study suggested that the utilization of detailed 3-D models can improve patient outcomes.

Do you have any other take-home messages about nephrectomy for practicing urologists?

The key is doing the correct operation for each particular patient. First decide whether the patient needs a partial or radical based on all the criteria we discussed. Then, based on your own experience, decide whether to do it open or robotically or refer it out to somebody else. I think that’s what’s in the best interest of the patient.

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