In overlap patients undergoing robot-assisted radical nephrectomy and IVC thrombectomy, no statistically significant differences in renal or safety/recovery outcomes were observed between segmental and non-segmental IVC resection, but renal non-inferiority of segmental resection was not established.
Key Findings
Results
After overlap weighting, no statistically significant differences in acute kidney injury (AKI) incidence were observed between segmental resection (SR) and non-segmental resection (NSR) groups.
Study included 120 patients with RCC and Mayo level II-IV IVC thrombus undergoing RARN-IVCT at Peking University Third Hospital (2014-2025)
45 patients underwent SR and 75 underwent NSR
Overlap weighting was applied to balance baseline variables between groups
AKI was a primary outcome measure alongside ΔSCr and ΔeGFR
Results
No statistically significant differences in change in serum creatinine (ΔSCr) or change in estimated glomerular filtration rate (ΔeGFR) were observed between SR and NSR after overlap weighting.
ΔSCr and ΔeGFR were primary renal safety outcomes
Analysis was performed in the overlap population after weighting to reduce selection bias
Despite lack of statistical significance, renal non-inferiority of SR versus NSR was not formally established
Authors note limitations including retrospective design, limited effective sample size, and unmeasured anatomic/hemodynamic confounding
Results
Segmental resection was associated with significantly lower red blood cell (RBC) transfusion volume compared to non-segmental resection.
Mean difference in RBC transfusion volume: -249.63 mL (95% CI: -443.20 to -56.05)
This difference was statistically significant (P = 0.011)
This was a secondary outcome finding favoring SR over NSR
The finding was observed after overlap weighting to balance baseline characteristics
Results
No statistically significant differences in complications or hospital stay were observed between SR and NSR after overlap weighting.
Complications and hospital stay were secondary outcomes
SR met non-inferiority and equivalence criteria for hospital stay and pneumonia
Overall complication profiles did not differ significantly between groups
OS (overall survival) was assessed exploratorily and also showed no statistically significant difference
Results
SR met non-inferiority/equivalence criteria for hospital stay and pneumonia, but renal non-inferiority of SR compared to NSR was not established.
Non-inferiority and equivalence testing was applied to selected outcomes including hospital stay and pneumonia
Renal non-inferiority was not established despite the absence of a statistically significant difference in renal outcomes
Authors conclude that planning should consider thrombus-wall interaction, caval patency, collateral outflow, and renal reserve
The inability to establish renal non-inferiority is attributed in part to limited effective sample size after weighting
Methods
SR is selected for cases with wall invasion, occlusion, and collateral outflow, making direct comparison with NSR prone to selection bias that overlap weighting was used to address.
This was a retrospective single-center cohort study design
Overlap weighting was chosen specifically to balance baseline variables between the inherently different SR and NSR patient populations
Key unmeasured confounders include anatomic and hemodynamic variables
The study population included Mayo level II-IV IVC thrombus cases, representing more complex disease
What This Means
This research suggests that for patients with kidney cancer (renal cell carcinoma) that has spread into the large vein leading to the heart (inferior vena cava), two surgical approaches — removing a segment of the vein (segmental resection) versus opening and cleaning the vein without removing it (non-segmental resection) — appear to produce similar outcomes in terms of kidney function, complications, and recovery time. The study used a statistical technique called overlap weighting to make a fairer comparison between the two groups, since segmental resection is typically reserved for more complicated cases where the tumor has grown into the vein wall. One notable finding was that patients who underwent segmental resection required less blood transfusion on average (about 250 mL less red blood cells), which was a statistically significant difference.
However, the study could not formally confirm that segmental resection is 'non-inferior' (not meaningfully worse) to non-segmental resection for kidney safety outcomes. This means that while no significant difference was detected, the study was not large or powerful enough to definitively rule out a potential disadvantage in kidney function with segmental resection. The study was limited by its retrospective, single-center design (120 patients at one hospital over about a decade), a relatively small effective sample size after statistical balancing, and the inability to account for all relevant anatomical and blood flow-related factors.
This research suggests that the choice between these two surgical techniques should be individualized, taking into account how much the tumor has grown into the vein wall, whether the vein is blocked, how blood is rerouting around the blockage, and the patient's baseline kidney function. These findings provide useful preliminary evidence for surgeons performing these complex robotic-assisted operations, but larger prospective studies would be needed to draw firmer conclusions.
Guan Y, Yan Y, Xie R, Ge L, Tian X, Wang G, et al.. (2026). Segmental versus non-segmental inferior vena cava resection during robot-assisted radical nephrectomy and thrombectomy: an overlap-weighted analysis.. World journal of urology. https://doi.org/10.1007/s00345-026-06725-2