AUA 2018: Inferior Vena Cava Level II Tumor Thrombectomy: Which is Best: Robot or Open?

San Francisco, CA (UroToday.com) In this plenary session, Drs. Leibovich and Gill once again debated the best approach to a Level II Tumor Thrombus.  Mark Soloway introduced the topic. He made some important baseline points:  This is one of the most complex procedures we do in Urology – and morbidity can be high in inexperienced hands. The key to success is preparation, experience, exposure and vascular control. He provided guidance regarding liver mobilization for level II and III thrombi and emphasized the need for a multi-disciplinary team. 

Both speakers are very experienced surgeons surrounded by experienced teams. 

Dr. Bradley Leibovich's opening slide covered his main take-home points. He specifically noted that the benefits of an open approach include proven oncologic efficacy, increased safety, lower cost, fewer complications, versatility to handle any complications, and the ability to maintain/teach open skills.

These continue to be rare cases. Of ~340,000 RCC cases/year, approximately <20,000 cases will involve tumor thrombus. 20% of those will be Level II thrombi. 

Key surgical principles of tumor thrombus surgery:

1. Assemble an experienced team (urologist, vascular surgeon, hepatobiliary surgeon, cardiac surgeon)
2. Operate on the vessels first – this is a vascular operation first, urologic operation second!
3. Ligate renal artery, no need to embolize
4. Isolate venous structures
5. Completely remove thrombus
6. Manage any distal bland thrombus
7. Repair/replace/patch Inferior Vena Cava (IVC) as needed

Surgeon volume matters – a recent study out of Canada demonstrated that >75% of deaths from IVC thrombus cases happen within the first 1-2 cases in a surgeon’s experience.3

Over the past few years there have been several series describing the efficacy and safety of robotic nephrectomy with IVC thrombectomy. In a recently published review1 of primarily level II (with some studies including level III) IVC thrombus treated with robotic IVC thrombectomy, the transfusion rate was 0-25%, length of stay 1-6 days, and complication rate of 0-25%. But as Dr. Leibovich notes, these are highly selected cases and there was no discussion as to the true “complexity” of the cases, specifically concurrent procedures, tumor thrombus characteristics, bland thrombus, and prior procedures. Based on prior work from Dr. Leibovich’s group, there are pre-operative factors available that can help predict the need for resection of the IVC, including AP diameter of the IVC at the renal vein ostia >24 mm, complete occlusion of the IVC at the renal vein ostia, and a right sided tumor2.

Predicting the probability of resection of the IVC (c-index 0.81):

  • 0 features: 2%
  • 1 feature: 8-11%
  • 2 features: 26-35%
  • 3 features: 64%
One of the advantages of open IVC thrombectomy that Dr. Leibovich is passionate about is the need to continue training urologic residents/fellows in open surgery. One of the hallmarks of a urologic oncologist is the ability to handle a malignancy surgically when adverse features are present. According to Dr. Leibovich, we must impart open surgical skills for cases that cannot be done robotically, as well as assure that open conversion will not need to be outsourced to other specialties. 

He also feels that in a condition that is so rare, teaching multiple approaches may dilute the understanding of management – better to teach it one way, as its so uncommon. Ultimately, caval thrombus cases are somewhat rare and there is inadequate volume to train surgeons in multiple techniques. 

Leibovich also argues that open IVC thrombectomy is safer than robotic thrombectomy. Open thrombectomy not only teaches skills critical for urologic oncologists, it also provides the ability to get multiple hands involved quickly, thwarting massive hemorrhage and potential morbidity.

A recently published study from China4 assessed robotic versus open level I-II IVC thrombectomy in a matched group comparison analysis. They compared 37 open procedures (from 2006-2014) to 31 robotic procedures (from 2013-2016) and used a propensity model adjusting for age, ASA score, tumor size and thrombus length. Open IVC thrombectomy was cheaper ($7,300 vs $13,000), but was associated with longer operative time (230 min vs 150 min, p<0.001 right sided tumors), more transfusions (55% vs 7%, p<0.001), and longer length of stay (9 days vs 5 days, p<0.001) compared to the robotic approach; overall complications favored robotic surgery (13% vs 33%, p=0.07). Dr. Leibovich argues that this study was based on small numbers and the authors adjusted for factors that do not impact the difficulty of surgery, thus leading to significant residual confounding.

Leibovich concluded with reiterating several take-home points for why he prefers open IVC thrombectomy: (i) there is proven oncologic efficacy, (ii) the ability to handle anything, (iii) low complication rates, (iv) less costly, (v) no difference in length of stay, (vi) ability to train and maintain open skills for trainees, and (vii) proven safety outcomes.




Inderbir Gill, MD, provided a rebuttal to Leibovich’s argument for open IVC thrombectomy by arguing that we should be doing level II IVC thrombus cases via a robotic approach. Dr. Gill notes that for skilled robotic surgeons, level II thrombi can be confidently performed robotically; there are already series describing robotic IVC thrombectomy for level III cases.5 Furthermore, according to Dr. Gill, we already have the skills necessary to perform these complex procedures robotically, as well as additional minimally invasive tools including intracaval balloon occlusion, patch grafting, and vena cavoscopy.6

Gill states that prior to every case, he consults with his radiologists to assess the likelihood of requiring IVC resection. He uses the criteria from Dr. Leibovich’s group to do so, including the following pre-operative factors: AP diameter of the IVC at the renal vein ostia >24 mm (OR 4.4), complete occlusion of the IVC at the renal vein ostia (OR 4.9), and a right sided tumor (OR 3.3)2

If there is a low probability of needing IVC resection, Dr. Gill feels it is feasible to perform robotic IVC thrombectomy for level 1-2 thrombi, level 2-3 thrombi, and for thrombi ≤11.6 cm in length. A recently published study from China4, discussed by Dr. Leibovich as well, noted that although robotic IVC thrombectomy was more expensive ($13,000 vs $7,300), the robotic approach was associated with shorter operative time (150 min vs 230 min, p<0.001 right sided tumors), fewer transfusions (7% vs 55%, p<0.001), shorter length of stay (5 days vs 9 days, p<0.001), and fewer complications (13% vs 33%, p=0.07) compared to the open approach.

Gill subsequently presented preliminary data from his institution (USC) comparing open to robotic cases, which is being finalized for publication and will be available shortly. The basic gist was that patients had less blood, less transfusion, rare conversion to open (7%), and comparable peri-operative outcomes – regardless of it being a level II or level III thrombus. 90-day and on-table mortality was less in the robotic cases; albeit, not statistically significant.

To conclude, Dr. Gill notes that going forward there should be a randomized trial for level II-III IVC thrombi (open vs robotic approach), we need to further explore neoadjuvant therapies for these advanced cases, we should re-evaluate the role of peri-operative kidney embolization, and refine the use of intra-IVC balloons.

His take-home point is that we cannot remain static. While he appreciates the work that Dr. Leibovich and other giants in the field have done to improve the open approach, he feels that we need to continue to push the boundaries and innovate.

References:
1. Abaza R, Eun DD, Gallucci M, et al. Robotic surgery for renal cell carcinoma with vena caval tumor thrombus. Eur Urol Focus 2016;2(6):601-607.
2. Psutka SP, Boorjian SA, Thompson RH, et al. Clinical and radiographic-predictors of the need for inferior vena cava resection during nephrectomy for patients with renal cell carcinoma and caval tumour thrombus. BJU Int 2015;116(3):388-396.
3. Toren P, Abouassaly R, Timilshina N, et al. Results of a national population-based study of outcomes of surgery for renal tumors associated with inferior vena cava thrombus. Urology 2013;82(3):572-577.
4. Gu L, Ma X, Gao Y, et al. Robotic versus Open Level I-II Inferior Vena Cava Thrombectomy: A Matched Group Comparative Analysis. J Urol 2017;198(6):1241-1246.
5. Gill IS, Metcalfe C, Abreu A, et al. Robotic Level III Inferior Vena Cava Tumor Thrombectomy: Initial series. J Urol 2015;194(4):929-938.
6. Kundavaram C, Abreau AL, Chopra S, et al. Advances in robotic vena cava tumor thrombectomy: intracaval balloon occlusion, patch grafting, and vena cavoscopy. Eur Urol 2016;70(5):884-890.

Moderator: Mark Soloway
Debators: Bradley Leibovich, MD, Mayo Clinic, Rochester, MN, Inderbir Gill, MD, USC, Los Angeles, CA

Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto, @tchandra_uromd at the 2018 AUA Annual Meeting - May 18 - 21, 2018 – San Francisco, CA USA

Read Drs. Leibovich and Gill's 2017 SUO Debate on IVC Thrombectomy
Bradley C. Leibovich, MD
IVC Thrombectomy for Level 2 Tumor Thrombus Versus an Open Approach
Inderbir S. Gill, MD:
IVC Thrombectomy for Level 2 Tumor Thrombus Versus a Robotic Approach
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