A Prospective Randomized Trial Comparing the Outcomes of Open Vs Laparoscopic Partial Nephrectomy

By David Ambinder, MD - September 27, 2022

Is laparoscopic surgery equivalent to open surgery when it comes to partial nephrectomies? According to a recent study published in The Journal of Urology, it may even be superior in certain respects.1 The use of partial nephrectomy has increased largely because it has been shown to reduce the risk of developing kidney failure, cardiovascular disease, and mortality while having equivalent oncologic outcomes and impact on quality of life when compared to radical nephrectomy.2 Tumor characteristics, including size and location within the kidney, largely determine whether the disease would be best managed with a partial nephrectomy instead of a radical nephrectomy. Minimally invasive approaches, including laparoscopic/robotic surgery are also becoming more frequently utilized, although there is little high-level evidence to support their use. The authors of the article conducted a prospective, randomized study design at a single institution to compare the complications and oncologic/functional outcomes of open and laparoscopic partial nephrectomy.

Comparing Open and Laparoscopic Nephrectomies

Among the inclusion criteria for patients enrolled into the study were a localized single renal mass <7 cm with no evidence of nodal or distant metastasis and evaluation by a urologist to determine the appropriateness of undergoing a partial nephrectomy. Exclusion criteria were based on kidney function, previous renal masses, contraindication for surgical extirpation, other kidney conditions (such as horseshoe kidney), history of nephrolithiasis, or an ectopic kidney. Patients were randomized and underwent an open or a laparoscopic partial nephrectomy over approximately 8 years, between 2012 and 2020, at a single institution with 4 experienced surgeons.

The authors describe that open partial nephrectomy was performed via a subcostal incision while laparoscopic partial nephrectomy was performed via a transperitoneal approach. In both the open and laparoscopic cohorts, the choice to use vascular clamping, ureteral stent placement, or application of glue was based on surgeon preference.

The researchers accounted for multiple variables, including preoperative demographics and tumor characteristics; operative and postoperative data, including perioperative and postoperative complications; postoperative kidney function; and oncologic outcomes. The primary endpoint was the incidence of postoperative surgical complications. Secondary outcomes included oncologic and functional outcomes at 3 and 12 months after surgery.

After determination of patient eligibility for partial nephrectomy, 84 patients were randomized to the laparoscopic arm and 96 patients were randomized to the open arm. Patient characteristics in the 2 cohorts were similar regarding age, body mass index, sex, comorbidities, baseline kidney function, preoperative EDTA function, history of previous abdominal surgeries, tumor size and R.E.N.A.L. nephrometry score (R=radius of the tumor; E=exophytic/endophytic properties; N=nearness of tumor’s deepest portion to the collecting system or sinus; A=anterior/posterior ; L=location). Importantly, 79 (94%) patients randomized to the laparoscopic arm underwent transperitoneal laparoscopic surgery while 1 underwent retroperitoneoscopy and 4 underwent open surgery (3 subcostal and 1 lumbotomy).

Of the patients randomized to the open partial nephrectomy arm, 77 (80%) underwent the study standard subcostal approach while 16 underwent an open lumbotomy approach and 3 underwent a laparoscopic transperitoneal approach. The intention-to-treat analysis during the perioperative period found no differences between the arms in terms of time, bleeding, or intraoperative complications. No difference in ischemia time was found when renal hilum clamping was used, and there was no difference in the incidence of surgical complications, need for blood transfusion, or the length of hospital stay (3 days regardless of approach). However, during their post-crossover analysis, the authors found a significant difference in blood loss (317 vs 530 mL) and need for blood transfusion (0% vs 6.2%) that favored the laparoscopic over the open approach.

Study Results

A total of 22.6% of patients in the laparoscopic cohort developed a Clavien-Dindo grade 2 or higher complication compared to 13.5% in the open partial nephrectomy cohort (P=0.1). The incidence of abdominal wall complications, including incisional hernia, abdominal wall bulging, seroma, keloid, surgical site infection, or abdominal pain necessitating an emergency room visit was significantly better in the patients in the laparoscopic cohort with the open cohort (13.1% vs 31.2%; P=0.004).

In terms of adverse events, the authors noted 1 death reported in the laparoscopic cohort after the patient presented with a urinary fistula. The patient was treated with a ureteral stent but developed a neurologic condition and subsequent sepsis and death. In the open cohort, 16 patients developed abdominal muscle atrophy with symptomatic incision bulging; 5 patients developed a urinary leak fistula, which was managed by urinary diversion, and 1 patient required a radical nephrectomy. Additionally, 3 patients developed massive hematuria owing to intrarenal pseudoaneurysms; 1 of these patients had spontaneous resolution while the other 2 required intravascular embolization.

At the 12-month follow-up there was consistently greater loss of renal function and higher incidence of worsening chronic kidney disease (CKD) classification among patients in the open cohort compared with the laparoscopic cohort. Regarding oncologic outcomes in the laparoscopic versus open cohorts, median tumor size (3.3 vs 3.7 cm), histological subtype, and rates of positive surgical margins (8.3% vs 6.2%) were not significantly different between the groups, and at the 4-year (48 months) follow-up, the rates of recurrence were similar.

The authors began their discussion by acknowledging that “when the study was designed, robotic surgery was not yet performed in our institution.” Furthermore, study enrollment was cut short because of the COVID-19 pandemic. However, this remains an important prospective randomized trial that is consistent with results reported in the literature. The authors note that their per-protocol analysis finding of significantly greater blood loss and need for transfusion in the open versus laparoscopic cohort is consistent with a meta-analysis conducted several years ago that showed less bleeding and shorter hospitalization stays for patients undergoing laparoscopic compared with open partial nephrectomy.3 However, they acknowledge that data on length of stay are based on hospital-specific protocols regardless of approach and thus are likely not meaningful for analysis.

In regard to the greater decline in renal function and worse CKD classification in the open versus laparoscopic cohort at 12 months, the authors note that a 2010 study found ischemia time to be an important predictor of preserved renal function.4 However, this finding was called into question in 2019, when Ebbing et al found that ischemia time was an independent risk factor for acute glomerular insufficiency but had no impact on long-term renal function.5

More recently, preserving renal parenchyma was shown to be associated with preserved renal function.6 This is consistent with the results of the current study, which found that although patients in the laparoscopic cohort had longer ischemia times, they did not have poorer renal function and in fact had preserved renal function. The authors mention that a secondary analysis of this study will be done to assess whether volume of residual renal parenchyma has an impact on glomerular filtration rate.

The authors concluded that while the open and laparoscopic approaches to a partial nephrectomy showed similar rates of surgical complications and oncologic outcomes, the open approach was associated with higher rates of abdominal wall complications and worse, preservation of renal function.

 

References

  1. Guglielmetti GB, Dos Anjos GC, Sawczyn G, et al. A prospective, randomized trial comparing the outcomes of open vs laparoscopic partial nephrectomy. J Urol. 2022;208(2):259-267. doi: 10.1097/JU.0000000000002695.
  2. Zini L, Perrotte P, Capitanio U, et al. Radical versus partial nephrectomy: effect on overall and noncancer mortality. Cancer. 2009;115(7):1465-1471. doi: 10.1002/cncr.24035.
  3. You C, Du Y, Wang H, et al. Laparoscopic versus open partial nephrectomy: a systemic review and meta-analysis of surgical, oncological, and functional outcomes. Front Oncol. 2020;10:583979. doi: 10.3389/fonc.2020.583979.
  4. Thompson RH, Lane BR, Lohse CM, et al. Every minute counts when the renal hilum is clamped during partial nephrectomy. Eur Urol. 2010;58(3):340-345. doi: 10.1016/ j.eururo.2010.05.047.
  5. Ebbing J, Menzel F, Frumento P, et al. Outcome of kidney function after ischaemic and zero-ischaemic laparoscopic and open nephron-sparing surgery for renal cell cancer [published correction appears in BMC Nephrol. 2019;20(1):86]. BMC Nephrol. 2019 Feb 4;20(1):40. doi: 10.1186/s12882-019-1215-3.
  6. Chen FM, Hu RJ, Jiang XN, Zhong SW, Tang S. The correlation between affected renal function and affected renal residual volume: a retrospective outcome of laparoscopic nephron-sparing partial nephrectomy with segmental renal artery blocking-up for localized renal tumors. Medicine (Baltimore). 2019;98(2): e13927. doi: 10.1097/ MD.0000000000013927.
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