Increased utilization of partial nephrectomy in the robotic surgery era

In the past, radical nephrectomy was considered to be the standard of care for localized renal tumours. Partial nephrectomy, also known as nephron sparing surgery, was often reserved for imperative indications such as solitary kidney, bilateral or hereditary renal tumours, chronic kidney disease or at risk of significant renal disease. However, partial nephrectomy has now been advocated to be the standard of care for renal masses up to 7 cm and guidelines support this. It is based on level 1 evidence that partial nephrectomy offers equivalent oncological outcomes while conferring the advantage of preserving renal function. A randomized prospective study confirmed the reduced risk of renal impairment. While it failed to show a significant reduction in the rate of overall mortality, retrospective studies have demonstrated that partial nephrectomy was associated with a reduced risk of developing cardiovascular disease as well as overall mortality. However, the results are limited by potential selection biases or unknown confounders inherent with retrospective studies. The major drawback of partial nephrectomy is an increased rate of perioperative morbidities and complications. This was especially relevant when laparoscopic excision became the standard approach for radical nephrectomy but open approach was still the most common technique for partial nephrectomy. Open partial nephrectomy (OPN) resulted in longer length of stay, increased risk of complications such as bleeding, pseudoaneurysm, urine leak, or poor cosmesis/abdominal bulge. However, over time laparoscopic partial nephrectomy became common and a lot of the disadvantages of the open approach were avoided. While it has several advantages compared to an open technique as a result of its minimally invasive nature, there have been limitations with its wide applicability among urologists as access and dexterity, precision and depth perception are not always present in a time critical environment. Robot-assisted technology has overcome these limitations and the evolution of minimally invasive surgery from laparoscopic to robot-assisted partial nephrectomy (RAPN) has allowed a rapid uptake in partial nephrectomy in the USA. In this issue of the journal, Ali et al. described changing trends in contemporary surgical management of renal tumours in Australia from 2000 to 2016. The key findings were a significantly increased rate of partial nephrectomy while the rate of radical nephrectomy has remained steady per population. RAPN accounted for less than 5% of all partial nephrectomies in 2010, whereas nearly 60% in 2016. There was also an increased rate of surgical treatment and the authors largely attributed to a significantly increased uptake in patients older than 75 years. This was the first study to report national surgical patterns of care for renal tumour management over 16 years using Medicare Benefits Schedule (MBS) codes. However, as the authors correctly acknowledged, it did not address any potential discrepancy in the type of procedures performed between private and public hospitals. The authors confirmed a significant increase in the uptake of RAPN in Australia. Due to downward stage migration with increased detection of incidental masses coupled with increasing availability of robotic technology at private hospitals, it is not surprising that the number of RAPN has dramatically increased. The study would have been more informative if other means of therapy such as laparoscopic partial nephrectomy or ablative therapy were incorporated as part of the analysis. Unfortunately, despite the anecdotal evidence of increased utilization of ablative therapy, there is no MBS item number for ablative therapy for renal mass to allow for meaningful comparison. What really matters is outcomes between different surgical modalities. A number of studies compared perioperative, oncological and functional outcomes of patients undergoing partial nephrectomy using different modalities of surgical treatment. Overall, RAPN resulted in equivalent long-term oncological and functional outcomes. However, it offered significantly superior perioperative outcomes compared to OPN. A systematic review and metaanalysis showed a lower rate of postoperative complications, transfusions and length of stay in patients undergoing RAPN compared to the OPN group. Furthermore, a number of technical modifications and technological refinements have enabled urologists to tackle more complex and larger renal masses using robotic approach. Some of these studies showed that RAPN would be a superior technique even for very complex tumours. Garisto et al. showed reduced blood loss, ischaemia time, transfusions rate and length of stay for highly complex renal masses. An Australian group also demonstrated reduced complications, estimated blood loss, length of hospital stays and fewer positive margins. Moreover, Camp et al. showed a significant reduction in costs at 1 year post-intervention following RAPN compared to OPN. Ali et al. also did not evaluate factors that could influence the treatment modality. A study published by our group demonstrated that the uptake of laparoscopy was significantly higher if surgery was performed at teaching hospitals, at private hospitals or at high volume centres >8 per year in New SouthWales. High hospital volume was also an independent factor for partial nephrectomy rather than radical nephrectomy. A Victorian study showed a trend towards a higher rate of radical and open nephrectomy in patients with lower socioeconomic status or residing in non-metropolitan areas. However, our study was published prior to the popularization of RAPN and the Victorian study did not specify if there was any RAPN case in the laparoscopic group. Surgeon and hospital volumes have also been demonstrated to play a crucial role in improving patient outcomes for a number of cancers including renal cell carcinoma. The majority of the studies were conducted in North America and the UK. The average number of renal surgery for renal cell carcinoma was 16 per surgeon and 39 per centre in the UK in comparison to 8 per surgeon and 10 per centre in the USA. Hospital volume and surgeon volume were independent predictors of perioperative outcomes of patients undergoing RAPN, with hospital volume playing a greater impact than surgeon volume. A systematic review and metaanalysis confirmed improved outcomes in the UK following the centralization of care. There is a paucity of information available to date in Australianbased population to assess whether it would also apply to the ANZ Journal of Surgery 9