The study, published in Frontiers in Urology, involved 413 patients with clear cell renal cell carcinoma, the most prevalent histological subtype of kidney cancer, accounting for roughly 70 to 80 percent of all cases. Renal cell carcinoma itself is the seventh most common malignancy worldwide and carries the highest mortality among urological cancers. Between June 2019 and April 2024, 312 of the patients in the cohort underwent partial nephrectomy while 101 underwent radical nephrectomy, with the final surgical decision made by attending urologic surgeons based on tumor anatomy, patient comorbidities, baseline kidney function, and surgeon expertise, reflecting real-world practice rather than a rigid algorithm. Notably, the R.E.N.A.L. Nephrometry Score, the study’s benchmark comparator, was calculated retrospectively for research purposes and was not formally used by the treating surgeons in their preoperative deliberations.

The R.E.N.A.L. Nephrometry Score, developed by Kutikov and Uzzo, classifies renal tumors into low, moderate, and high complexity groups based on cross-sectional imaging, assigning points for radius, endophytic or exophytic growth, nearness to the collecting system, anterior or posterior position, and location relative to the polar lines. More than ten competing scoring systems exist, including the PADUA score and the C-index, but the RNS was chosen for comparison because of its widespread adoption, its well-established correlation with perioperative outcomes, its extensive multi-center validation, and its intuitive component-based structure. Its fundamental limitation, however, is that it quantifies anatomy alone. Preoperative biopsy can probe tumor biology, but it is invasive, prone to sampling error, and carries procedural risks, leaving a clear gap for a non-invasive tool that captures quantitative tissue characteristics beyond what the eye can see on conventional images.

That gap is precisely where radiomics enters the picture. Radiomics is the high-throughput extraction of hundreds of quantitative features from medical images, converting what radiologists traditionally interpret qualitatively into reproducible numerical data. Subvisual texture patterns in tumors have been shown to correlate with pathological grade, genotype, and clinical outcomes across multiple cancer types, including kidney cancer. The research team extracted a total of 1,210 features from each tumor’s corticomedullary-phase CT scan, a contrast-enhanced imaging phase chosen because it best captures tumor vascularity and heterogeneity. The features spanned seven classes: first-order statistics describing voxel intensity distributions, three-dimensional shape descriptors, and five texture matrix families including the gray-level co-occurrence, run length, size zone, dependence, and neighboring gray tone difference matrices.

Rigorous standardization underpinned the entire pipeline. Images were resampled to isotropic 1-millimeter voxels, intensity histograms were normalized, and Laplacian of Gaussian filters and Daubechies-4 wavelet transforms were applied to capture texture information at multiple spatial scales, all in accordance with the Image Biomarker Standardization Initiative guidelines. Three blinded observers independently segmented tumors in 50 randomly selected cases to assess reproducibility, and features were retained only if their intraclass correlation coefficients exceeded 0.75 for both inter- and intra-observer agreement. That filter kept 851 features, or about 70 percent of the total, with a median ICC of 0.89. The team then applied LASSO regression, a machine-learning technique that penalizes less informative variables and shrinks their coefficients toward zero, performing feature selection exclusively within a training cohort of 289 patients to prevent data leakage. Six features survived the selection, and the resulting radiomic score was tested in an independent internal validation cohort of 124 patients.

The results were striking. The radiomic model achieved an area under the receiver operating characteristic curve of 0.886, with a 95 percent confidence interval of 0.81 to 0.91, compared with 0.793 for the nephrometry score model, a difference confirmed as statistically significant by the DeLong test with a P-value of 0.015. At the optimal threshold, the radiomic model delivered sensitivity of 83.9 percent versus 71.3 percent, specificity of 82.1 percent versus 74.6 percent, and accuracy of 83.2 percent versus 72.8 percent. Calibration, the agreement between predicted probabilities and actual outcomes, was also superior, with a Brier score of 0.11 against 0.16. Decision curve analysis, which quantifies the clinical net benefit of using a model across a range of decision thresholds, showed the radiomic model providing greater value across most clinically relevant probabilities, yielding a net benefit of 0.32 versus 0.21 for the anatomical score at a threshold of 0.6.

To open the black box of machine-learning prediction, the researchers applied SHAP analysis, a game-theoretic interpretation method that quantifies each feature’s contribution to individual predictions. Tumor size, captured by the maximum two-dimensional diameter, emerged as the single most influential predictor, which aligns with the well-known relationship between tumor dimensions and surgical complexity. But texture features ranked close behind, particularly a gray-level co-occurrence measure and a texture strength descriptor. Lower values of the co-occurrence feature, indicating less complex and more predictable internal texture, were associated with a higher likelihood of partial nephrectomy. This makes biological sense: increased texture complexity in clear cell renal cell carcinoma has been linked to higher Fuhrman grade, greater microvascular density, and increased intratumoral heterogeneity, all of which can produce more infiltrative growth patterns, less distinct pseudocapsules, and more necrotic areas that complicate dissection and reconstruction.

Perhaps the most intriguing finding concerned the limits of the traditional score itself. The relationship between nephrometry complexity and surgical approach was non-monotonic in this cohort: radical nephrectomy rates were 15.2 percent for low-complexity tumors, 34.7 percent for moderate-complexity tumors, and just 15.2 percent for high-complexity tumors. The authors caution that this counterintuitive pattern may reflect selection bias, the small number of high-complexity cases, or institutional practice patterns favoring attempted nephron-sparing surgery even in difficult cases. Interestingly, larger maximum diameter predicted a higher probability of partial nephrectomy in this dataset, likely because surgeons were more willing to attempt nephron-sparing surgery for larger but anatomically favorable peripheral tumors, while small but deeply embedded or central lesions, technically challenging despite their size, more often resulted in radical nephrectomy. The combined model integrating both the radiomic score and the anatomical score reached an AUC of 0.888, statistically indistinguishable from radiomics alone, suggesting the quantitative imaging signature subsumed most of the anatomical information.

The authors are appropriately candid about the caveats. The endpoint predicted was the actual surgical procedure performed, not an objective measure of tumor resectability, meaning the model captures institutional decision-making patterns that integrate surgeon judgment and patient factors. There is also a degree of circularity in the comparison: because anatomical assessment informed the real surgical decisions, the RNS model’s performance was likely biased upward, making the radiomic model’s superiority all the more noteworthy. Fuhrman grade differed between the surgical groups but is unknown preoperatively; a post-hoc sensitivity analysis adjusting for grade confirmed the radiomic model’s performance remained strong at an AUC of 0.875, indicating the imaging signal is not merely a surrogate for tumor aggressiveness. The study was single-center and restricted to pathologically confirmed clear cell histology, which is rarely known before surgery, and radiomic features remain sensitive to scanner manufacturers and acquisition protocols.

Those limitations explain why the researchers emphasize that prospective, multi-center validation is essential before any routine clinical adoption, with calibration to local partial nephrectomy rates and eventual linkage to long-term oncological outcomes such as overall and progression-free survival. Still, the proof of concept is compelling: a standard preoperative CT scan, already acquired in virtually every patient with a kidney mass, contains quantitative information about tumor size and internal heterogeneity that predicts surgical decision-making more accurately than the anatomical score that has dominated the field for over a decade. If validated externally, such radiomic decision-support tools could help surgeons and patients navigate the choice between nephron-sparing surgery and radical nephrectomy with greater confidence, preserving kidneys where possible while avoiding futile attempts at complex reconstructions, all without a single additional test, needle, or scan.

Subject of Research: CT-based radiomics for predicting partial nephrectomy likelihood in clear cell renal cell carcinoma

Article Title: Radiomic model versus R.E.N.A.L. nephrometry score for predicting the likelihood of undergoing partial nephrectomy in clear cell renal cell carcinoma

Article References: Liu, F.-D., Yu, H.-L., Wang, D.-J., Ju, X.-B., & Yang, Y.-H. (2026). Radiomic model versus R.E.N.A.L. nephrometry score for predicting the likelihood of undergoing partial nephrectomy in clear cell renal cell carcinoma. Frontiers in Urology, 6, Article 1928982. https://doi.org/10.3389/fruro.2026.1928982

Image Credits: AI Generated

DOI: 10.3389/fruro.2026.1928982

Keywords: radiomics, clear cell renal cell carcinoma, partial nephrectomy, R.E.N.A.L. nephrometry score, CT imaging, machine learning, LASSO regression, SHAP analysis, tumor heterogeneity, nephron-sparing surgery, urologic oncology, decision curve analysis

The study, published in BMC Cancer by a team led by Zhibin Fu, Linhui Wang, and Jiazi Shi from the Naval Medical University hospitals in Shanghai, set out to answer a deceptively simple question: what is the long-term trajectory of renal parenchymal volume, the functional meat of the kidney, after tumor removal, and how does that trajectory relate to overall kidney function? To find out, the team sifted through the records of 1,947 patients who underwent laparoscopic or robot-assisted partial nephrectomy for renal tumors between January 2015 and December 2021. From that pool, 149 patients with confirmed renal cell carcinoma and complete serial imaging plus clinical follow-up made it into the final analysis.

The technical centerpiece of the work is three-dimensional CT volumetry. Rather than relying on the crude proxy of kidney length or the blunt instrument of a single blood test, the researchers measured the actual volume of functioning renal tissue on each side of the body at three time points: before surgery, at a first postoperative follow-up between one and six months, and at a last follow-up at least 36 months after the operation. Using contrast-enhanced CT images reconstructed at one-millimeter slice thickness, they employed a semi-automated segmentation workflow with an edge-snapping magnetic-lasso tool, manually corrected the contours, and verified them on coronal and sagittal reformations before letting the software calculate three-dimensional volumes. Kidney function was tracked in parallel using the estimated glomerular filtration rate, or eGFR, calculated with the CKD-EPI equation, the standard formula used to stage chronic kidney disease.

The numbers tell a clear story of slow attrition. The ipsilateral kidney, the one that was operated on, started at a median parenchymal volume of 172.57 cubic centimeters before surgery. By the first follow-up visit, a median of 2.8 months after the operation, it had already fallen to 156.66 cubic centimeters, reflecting the immediate loss of tissue removed with the tumor along with early postoperative changes. But the shrinkage did not stop there. At the last follow-up, the volume had dropped further to 136.04 cubic centimeters, which works out to an annualized decline of 3.00 percent during the late follow-up period. In other words, the operated kidney kept losing functional tissue year after year, long after the surgical wound had healed.

Perhaps the most striking finding concerns the contralateral kidney, the untouched organ on the other side of the body. Conventional wisdom holds that when one kidney loses capacity, the other hypertrophies to pick up the slack, a phenomenon well documented after living kidney donation and radical nephrectomy. Yet in this cohort, the healthy kidney barely changed: 175.02 cubic centimeters before surgery, 179.92 cubic centimeters at the first follow-up, and 178.80 cubic centimeters at the last. The researchers found no significant evidence of compensatory hypertrophy. Total parenchymal volume across both kidneys declined at an annualized rate of 1.08 percent, and eGFR declined at 0.65 percent per year, with wide interquartile ranges indicating that some patients fared considerably worse than others.

To understand why some kidneys atrophy faster than others, the team ran univariate and multivariate linear regression models covering demographics, comorbidities, tumor characteristics, and surgical parameters. Three factors emerged as independently associated with the annualized rate of ipsilateral volume loss. Tumor composition mattered: patients with cystic tumors, which are fluid-filled and often require less parenchymal resection, showed different atrophy rates than those with solid tumors, with a p-value of 0.028. Surgical method also played a role, with robot-assisted procedures differing from laparoscopic ones at p equal to 0.048, a result that will feed the ongoing debate over whether the robot’s enhanced dexterity and finer suturing translate into better long-term organ preservation. Finally, ischemia type was associated with volume loss at p equal to 0.023, comparing patients whose renal blood flow was not temporarily clamped with those who underwent warm ischemia, the period during which the kidney is deliberately starved of blood while the surgeon reconstructs it.

Intriguingly, no independent predictors were identified for the annualized change rates of the contralateral kidney, total parenchymal volume, or eGFR. The healthy kidney’s behavior and the overall functional decline appear to follow their own course, resistant to the clinical variables the team tested. When the researchers instead looked at the absolute values at the last follow-up, a different set of relationships surfaced. Final total parenchymal volume was independently associated with patient age and preoperative volume measurements, while final eGFR was independently predicted by age, preoperative contralateral volume, and preoperative eGFR. The practical implication is sobering but useful: the best predictor of how a patient’s kidneys will function years after surgery is largely written into the patient before the first incision is made.

The disconnect between volume and function deserves attention. A three percent annual loss of ipsilateral tissue did not translate into a proportionally steep eGFR decline, likely because the global filtration rate blends contributions from both kidneys and because the relationship between parenchymal mass and filtration capacity is nonlinear. This is precisely where the authors argue CT volumetry earns its place. By measuring each kidney separately, volumetry offers a window into split renal function that serum creatinine and eGFR cannot provide. A stable eGFR can mask progressive atrophy on the operated side that only becomes clinically meaningful if the other kidney later falters, a scenario relevant to patients at risk of chronic kidney disease from diabetes, hypertension, or future contralateral tumors.

The study’s design carries caveats worth noting. It was a retrospective cohort approved by the Institutional Review Board of Changzheng Hospital and conducted under the Declaration of Helsinki, drawing on patients who happened to have complete serial imaging, which may introduce selection bias toward healthier or more closely monitored individuals. The ischemia finding, the authors note, is exploratory after adjustment. The median follow-up of 47.4 months, with an interquartile range of 36.0 to 60.4 months, is long by surgical oncology standards but still may not capture atrophy trajectories over decades. Funding came from the National Natural Science Foundation of China and the Changfeng Talent Development Program, and the authors declared no competing interests.

Even with those limitations, the message for patients and clinicians is actionable. Partial nephrectomy remains the standard of care for localized renal cell carcinoma precisely because it spares tissue and protects long-term kidney function compared with radical removal of the whole organ. This study does not challenge that standard; it refines the follow-up playbook. The operated kidney is not a finished structure once the tumor is out. It is a slowly remodeling organ whose parenchyma continues to atrophy at a measurable, predictable clip, and the opposite kidney, contrary to textbook expectations, does not reliably enlarge to compensate. The authors recommend integrating CT-based volumetric assessment into long-term postoperative surveillance, so that creeping volume loss can be detected and weighed against blood-based function measures before it becomes a clinical problem. For the growing population of kidney cancer survivors living decades after surgery, that shift from snapshot monitoring to longitudinal volumetric tracking could prove one of the quieter but more consequential legacies of this research.

Subject of Research: Long-term changes in renal parenchymal volume and kidney function after minimally invasive partial nephrectomy for renal cell carcinoma

Article Title: Changes in renal parenchymal volume and renal function after minimally invasive partial nephrectomy for renal cell carcinoma at median 47.4-month follow-up

Article References: Fu, Z., Wen, Q., Wu, C., Chen, F., Ni, J., Wang, J., Wang, J., Zhang, Z., Chen, M., Wu, Z., Wang, L., & Shi, J. (2026). Changes in renal parenchymal volume and renal function after minimally invasive partial nephrectomy for renal cell carcinoma at median 47.4-month follow-up. BMC Cancer. https://doi.org/10.1186/s12885-026-16996-y

Image Credits: AI Generated

DOI: 10.1186/s12885-026-16996-y

Keywords: renal cell carcinoma, partial nephrectomy, renal parenchymal volume, eGFR, CT volumetry, kidney function, warm ischemia, robot-assisted surgery, laparoscopy, chronic kidney disease, surgical oncology, nephrology

The new research, published in CVIR Oncology, pooled nine years of experience from three specialist centers in the United Kingdom, the United States, and Spain. The retrospective analysis drew on a prospectively maintained database of patients treated with percutaneous IRE between May 2015 and October 2024, using the NanoKnife 3.0 System. Every case involved a biopsy-proven renal cell carcinoma that a multidisciplinary tumor board had deemed unsuitable for partial or radical nephrectomy, or for conventional thermal ablation, typically because the tumor pressed against vital structures, sat within a solitary kidney, or the patient carried significant comorbidities.

The cohort comprised 68 patients with a mean age of 66.9 years, harboring 71 tumors with a mean diameter of 2.83 centimeters. These were not simple lesions: the median RENAL Nephrometry score, a standardized measure of anatomical complexity, was 9, placing them among the most challenging tumors treated anywhere. Nearly 58 percent were entirely endophytic, meaning they grew wholly within the kidney’s interior, and almost half were hilar tumors touching the renal artery or vein. Strikingly, 93 percent of the tumors lay less than one millimeter from a vital structure, including the ureter, colon, renal vessels, collecting system, and in rare cases the inferior vena cava, liver, small bowel, or spleen.

IRE works in a fundamentally different way from the radiofrequency, cryoablation, and microwave techniques that dominate image-guided ablation. Rather than heating or freezing tissue, the technology delivers high-voltage electrical impulses through fine needles placed around the tumor under ultrasound or CT guidance. These pulses create irreversible nanopores in the lipid membranes of cancer cells, disrupting cellular homeostasis, causing loss of intracellular contents and ultimately triggering apoptotic cell death. Crucially, the technique spares structures rich in collagen, such as ureters, blood vessels, and bile ducts, because their architecture does not depend on the cellular membranes that the pulses destroy. It also avoids the heat-sink effect, in which flowing blood dissipates thermal energy and undermines ablation near large vessels.

The procedure itself is technically demanding. Patients undergo general anesthesia with deep neuromuscular blockade to ensure complete muscle paralysis, since the electrical pulses would otherwise provoke violent contractions. Interventional radiologists, each with more than a decade of ablation experience, inserted an average of 4.56 monopolar electrodes to bracket each tumor. A test run of 20 pulses per electrode pair confirmed electrical conductivity, allowing adjustment of voltage to keep delivered current between 20 and 40 amperes, before the full treatment of 90 pulses per electrode pair was delivered with cardiac gating. Mean anesthesia time was 107 minutes, and patients typically stayed 1.6 days in hospital.

The headline results were encouraging. Technical success, meaning complete coverage of the tumor by the ablation zone, was achieved in 100 percent of sessions. Primary technique efficacy, defined as no residual enhancing tumor at the one-month scan, was 77.5 percent. While that figure trails some earlier single-center series, the authors emphasize that their tumors were larger and far more complex than those in comparable studies, and efficacy fell significantly as tumor size rose, particularly beyond 3.5 centimeters. Importantly, the modest primary efficacy did not translate into poor long-term cancer control: when residual disease was salvaged with a single additional ablation session, local control reached 95.8 percent, and five-year local tumor progression-free survival stood at 84.4 percent, rising to 81.1 percent at seven years.

Safety data were equally notable. Only two major adverse events occurred among 71 procedures, a rate of 2.8 percent: one permanent ureteric injury requiring long-term stenting and one episode of hematuria that resolved after stent removal. By comparison, published series of cryoablation for completely endophytic tumors report major complication rates approaching 10 percent, and robotic partial nephrectomy series report grade 3 or higher complications of around 17.5 percent. Kidney function was well preserved, with a mean decline in estimated glomerular filtration rate of just 7.5 ml/min/1.73m2, and only 10 percent of patients experiencing a clinically significant drop of more than 25 percent. Oncological durability was also reassuring, with cancer-specific survival of 98 percent at five years and metastasis-free survival of 91 percent.

Perhaps the most striking finding came from the composite ‘trifecta’ outcome, borrowed from surgical practice and combining primary efficacy, absence of major complications, and less than 25 percent decline in kidney function. IRE achieved the trifecta in 68.6 percent of cases, exceeding the 58.8 percent reported for thermal ablation and the 65.3 percent for robotic partial nephrectomy in comparable multicenter analyses of endophytic tumors. The authors suggest this may reflect IRE’s inherent suitability for tumors hugging critical structures, though they caution that head-to-head prospective comparisons are still needed before declaring superiority. They also describe practical refinements, including placing the electrode nearest a vital structure as the anode so pulses fire away from it, and using pre-operative ureteric stents in high-risk cases to guard against injury.

The study is not without limitations. It was retrospective, lacked a contemporaneous control group, involved only four operators across three centers, and did not employ centralized imaging review. Its results apply most directly to the kind of complex, high-risk tumors referred to specialist centers. Nevertheless, as the largest and longest-followed series of IRE for renal cancer to date, it provides the strongest real-world evidence yet that this electric-pulse technology deserves a firm place in the kidney cancer toolkit. For the growing population of patients with tumors once considered untreatable without sacrificing a kidney, the message from this nine-year, three-country experience is clear: irreversible electroporation can destroy the cancer while preserving both the organ and its function.

Subject of Research: Real-world outcomes of irreversible electroporation for complex small renal cell carcinomas unsuitable for surgery or thermal ablation

Article Title: MulticentRe rEal World outcomes of IrReversible Electroporation for complex small kiDney cancers (REWIRED)

Article References: MulticentRe rEal World outcomes of IrReversible Electroporation for complex small kiDney cancers (REWIRED). (n.d.). https://doi.org/10.1007/s44343-026-00049-z

Image Credits: AI Generated

DOI: 10.1007/s44343-026-00049-z

Keywords: irreversible electroporation, kidney cancer, renal cell carcinoma, image-guided ablation, small renal mass, NanoKnife, interventional radiology, nephron-sparing treatment, cryoablation, partial nephrectomy, RENAL nephrometry score, trifecta outcome