The clinical problem the Italian team set out to address is well known to anyone who works in pediatric oncology. When a child is diagnosed with a malignant renal mass, the surgical team must decide whether to remove the entire kidney, a procedure called radical nephrectomy, or to attempt nephron-sparing surgery, in which only the tumor and a thin margin of healthy tissue are excised. Nephron-sparing surgery is strongly preferred whenever it is safe, because children who keep functioning kidney tissue face a lower lifetime risk of chronic kidney disease, hypertension, and the long-term consequences of reduced renal reserve. But deciding whether the tumor can be safely shaved away from vital vessels and collecting structures requires an exquisitely detailed understanding of each patient’s unique anatomy — something that flat CT and MRI slices, read one at a time, do not always convey intuitively even to experienced surgeons.

The Turin group, led by pediatric urological surgeon Elisa Cerchia together with colleagues from the hospital’s pediatric surgery, oncology, and radiology units and the urology department of the University of Torino, tested a straightforward technical workflow. Standard abdominal MRI or CT examinations were performed for each patient as part of normal clinical care. The image data, stored in the universal DICOM format that medical scanners produce, were then imported into segmentation software. Segmentation is the computational process of outlining, slice by slice, the boundaries of each structure of interest — the tumor, the renal artery and its branches, the renal vein, the healthy kidney parenchyma, and the urinary collecting system. Once each structure is traced, the software renders it as a colored, fully rotatable three-dimensional object that can be zoomed, turned, made translucent, or viewed from any angle on a screen, effectively letting the surgeon fly through the child’s anatomy before making a single incision.

Eight patients, four boys and four girls, with complex renal masses were included in the study. For each child, the 3D virtual reconstruction was completed before surgery and reviewed by the surgeons and the pediatric radiologist involved in the case. To evaluate the technology rigorously rather than anecdotally, the team designed a modified closed-ended questionnaire administered in two phases, one before the operation and one afterward. Respondents compared the 3D models directly against the conventional imaging studies, rating how well each modality displayed the tumor and its relationships with arteries, veins, and the urinary tract, and assessing whether the reconstruction helped define the criteria for choosing nephron-sparing surgery over radical removal. The questionnaire also asked whether the models were practical to consult during the operation itself.

The statistical results were striking. For the tumor, the arteries, and the veins, the 3D virtual reconstructions were rated significantly better than conventional imaging, with p-values below 0.0001 for each of those structures — a level of significance that indicates the difference is extremely unlikely to be a statistical fluke even in a small case series. The urinary tract was the one exception; here the advantage of the 3D models did not reach statistical significance, with a p-value of 0.0888, suggesting that the collecting system may already be adequately visualized by standard scans or that segmentation of this thin-walled structure is technically harder to render convincingly. Even so, the overall pattern was unmistakable: the interactive models outperformed the flat images that surgeons have relied on for decades.

Perhaps the most clinically meaningful finding concerned surgical decision making. The study found that 3D virtual reconstruction was significantly more effective in defining the elective criteria for nephron-sparing surgery, with a p-value of 0.0003. In practical terms, this means the models helped surgeons judge whether a tumor could be removed while preserving healthy kidney tissue — the single most consequential decision in these operations. The questionnaire results also showed that the models were fundamentally easier to use during surgery than conventional images, with a p-value of 0.0006. A surgeon in the operating room can glance at a rotatable 3D model and instantly re-orient themselves in three-dimensional space, whereas scrolling through stacks of two-dimensional slices mid-operation is cumbersome and mentally taxing.

In the series, the eight children underwent a total of seven recorded operations: four radical nephrectomies and three nephron-sparing procedures. That three of the children could be treated with kidney-preserving surgery at all reflects the kind of complex, carefully selected cases for which preoperative three-dimensional planning is most valuable. In tumors judged too large or too centrally located for partial removal, the models still contributed by clarifying vascular anatomy before a radical nephrectomy, where precise knowledge of the renal artery and vein is essential for safe vessel control. The authors conclude that 3D virtual reconstruction is a genuinely useful tool in the preoperative evaluation of children with complex renal masses and that it facilitates nephron-sparing surgery in selected patients.

The technical pipeline behind these results deserves attention because it is reproducible in any hospital with standard imaging equipment. No additional scanning is required; the same DICOM datasets acquired for diagnosis feed the reconstruction. Segmentation software separates the anatomy into labeled structures, and rendering engines assemble them into interactive volumes. Some centers in the broader field go further and 3D-print physical models from the same data, which can be sterilized and brought into the operating theater, but the Turin study focused on the virtual models themselves, which require no printing hardware and can be shared instantly across the surgical team, from the operating room to the tumor board where treatment decisions are made.

What makes the study especially credible is its multidisciplinary design. The questionnaire was completed not only by the operating surgeons but also by the pediatric radiologist responsible for interpreting the original scans, meaning the comparison between 3D and conventional imaging was evaluated from multiple professional perspectives. The work also drew on collaboration with adult urological surgeons at the Città della Salute e della Scienza hospital in Turin, bringing experience from the larger field of kidney surgery into the pediatric arena. The project received no external funding, and the authors declare no competing interests, with technical support for the reconstruction workflow acknowledged from a collaborating company. The study was approved by the local ethics committee, and informed consent was obtained from each child’s parents or guardian in accordance with hospital rules.

Caveats remain, as they do with any small, single-center case series. Eight patients cannot establish how often 3D planning changes the final operative decision, whether it shortens operative times, reduces complications, or improves long-term kidney function — outcomes that will require larger, ideally multi-center comparative studies. The near-significant result for the urinary tract hints that some structures remain harder to model than others. Still, the consistency and strength of the reported significance levels, particularly for tumors and blood vessels, give the findings real weight. For a specialty in which the stakes are measured in decades of renal health for young patients, the message from Turin is compelling: letting surgeons rehearse a child’s cancer in three dimensions before entering the operating room is no longer a futuristic gimmick but a practical, statistically validated planning tool that may help more children keep the kidney tissue they will need for the rest of their lives.

Subject of Research: Use of 3D virtual reconstruction from MRI and CT scans for preoperative planning of oncologic renal surgery in children

Article Title: 3D virtual reconstruction: usefulness in preoperative planning for oncologic renal surgery in children

Article References: Cerchia, E., Ruggiero, E., Teruzzi, E., Serpentino, M., Cirigliano, L., Quarello, P., Petraz, M., Catti, M., Allasia, M., Gontero, P., Fagioli, F., & Nappo, S. G. (2026). 3D virtual reconstruction: usefulness in preoperative planning for oncologic renal surgery in children. 3D Printing in Medicine. https://doi.org/10.1186/s41205-026-00340-y

Image Credits: AI Generated

DOI: 10.1186/s41205-026-00340-y

Keywords: 3D virtual reconstruction, pediatric surgery, renal tumors, nephron-sparing surgery, surgical planning, 3D Printing in Medicine, DICOM segmentation, pediatric oncology, kidney cancer, preoperative imaging, MRI, CT

The study, conducted at a single center between May 2008 and February 2020, followed 48 consecutive patients who were treated for a total of 53 biopsy-confirmed papillary renal cell carcinoma tumors. These were not healthy surgical candidates: the patients had been deemed unfit for partial nephrectomy, the current gold-standard operation for localized kidney cancer, because of advanced age, impaired kidney function, or poor overall condition, while some had simply declined surgery. Every case was reviewed by a multidisciplinary tumor board that included urologists, oncologists, radiologists, pathologists, and radiation oncologists before cryoablation was chosen. The cohort was predominantly male, with 39 men and 9 women, and the median age was 69.5 years, with patients ranging from 36 to 88 years old.

Papillary renal cell carcinoma is a distinct entity within the family of kidney cancers. While clear cell renal cell carcinoma is the most common histological type, papillary tumors account for roughly 10 to 15 percent of all renal cell carcinomas and are generally associated with better outcomes. The World Health Organization formally listed the entity in its 2016 classification of renal tumors, and pathologists further divide papillary tumors into two subtypes: type 1, which tends to be slower growing and more indolent, and type 2, which carries more aggressive features such as higher tumor grade, necrosis, and lymphovascular invasion. In the French series, type 1 tumors dominated the cohort, making up 46 of the 53 lesions, or 88.8 percent, while type 2 tumors accounted for the remaining 11.2 percent.

The technical execution of the procedure reveals why cryoablation has become such a powerful tool in interventional oncology. All treatments were performed by experienced interventional radiologists under general anesthesia or sedation, with the patient staying in hospital. Using computed tomography or magnetic resonance imaging for guidance, the radiologists inserted between two and four thin cryoprobes, typically 15 to 17 gauge, directly through the skin and into the tumor. The number, type, and positioning of the probes were tailored to each tumor’s size, location, and morphology, with the goal of enveloping the entire tumor in a lethal ice ball that extended 5 to 10 millimeters beyond its visible margins. For MRI-guided procedures, the team used MRI-compatible probes and near real-time multiplanar MRI fluoroscopy, allowing them to watch the ice ball grow in three dimensions as it formed.

Each ablation followed a standardized freeze-thaw protocol: two freezing cycles of 10 minutes each, separated by a 10-minute passive thawing period. This repetition is critical to the biology of cryodestruction. Rapid freezing causes ice crystals to form inside and around cells, rupturing their membranes, while the thawing and refreezing cycles amplify vascular damage, cutting off the tumor’s blood supply and ensuring that cells at the margin of the ice ball, where temperatures are less extreme, are still lethally injured. When tumors sat close to vulnerable structures such as the bowel or the abdominal wall, the team performed hydro-dissection or pneumo-dissection, injecting fluid or gas to physically push those organs out of harm’s way. In one striking example described in the study, sterile gloves filled with warm saline were placed over the skin at the probe entry sites to prevent frostbite, because MRI-compatible cryoprobes are not insulated along their shafts.

The results were striking on nearly every measure. Technical efficacy, defined as the absence of contrast enhancement and tumor enlargement on imaging within three months of the procedure, was achieved in all 53 tumors, a 100 percent success rate in destroying the treated lesion. The overall complication rate was just 11 percent, and every single complication was minor, classified as grade 2 or lower on the standard Clavien-Dindo scale. No patient required hemodialysis after treatment, a crucial finding given that many of these patients already had compromised kidney function, and a quarter of the cohort had only a single kidney. The median hospital stay was three days, and the median procedure took 127 minutes.

Oncologic outcomes were equally impressive. Only three of the 53 tumors, or 5.7 percent, recurred locally during follow-up, with a mean time to recurrence of 36 months. Two of the recurrences occurred in type 1 tumors and one in a type 2 tumor, a difference that was not statistically significant but is consistent with the known biology of the more aggressive type 2 subtype, which in this study also carried higher International Society of Urologic Pathologists grade scores. Two of the three recurrences were successfully treated with a second cryoablation. When these salvage treatments were factored in, the five-year estimates for local recurrence-free survival reached 95.9 percent for primary treatment and 97.8 percent for secondary effectiveness. Most remarkably, cancer-specific survival and metastasis-free survival were both 100 percent: no patient died of papillary renal cell carcinoma, and no patient ever developed distant metastases. Overall survival at five years was 90.3 percent, with the deaths that did occur attributable to unrelated cancers such as gastric, lung, and duodenal malignancies.

Perhaps the most provocative comparison in the study is with surgery itself. The authors point to a large surgical series of 626 patients with papillary renal cell carcinoma treated with partial nephrectomy, in which five-year cancer-specific survival was 83 percent, local recurrence-free survival was 91 percent, and overall survival was 82 percent, all figures lower than those reported in the cryoablation cohort. The authors are careful to caution against overinterpreting this comparison: there was no direct head-to-head analysis, the surgical series involved larger tumors averaging 4 to 5 centimeters compared with 2 to 3 centimeters in the ablation studies, and the sample sizes differ dramatically. Still, the findings add to a growing body of evidence that thermal ablation can match surgical outcomes for early-stage kidney tumors while avoiding the risks of major surgery, with prior studies showing fewer complications and shorter hospital stays for ablated patients.

The study does carry limitations that the authors acknowledge candidly. Its retrospective design and relatively small sample size, a consequence of the rarity of papillary renal cell carcinoma compared with the clear cell type, mean that larger multicenter studies will be needed to confirm the results. The effect of operator experience was not formally evaluated, although the authors note that their center performs more than 60 renal cryoablations per year, suggesting a consistently high standard of practice. The potential for inter- and intra-observer variability in imaging assessments was also not eliminated. And because the cohort was dominated by type 1 tumors, the findings for the more aggressive type 2 subtype rest on only seven lesions, a reminder that subtype-specific evidence remains thin.

Even with those caveats, the message for clinical practice is clear. For patients with biopsy-confirmed, localized papillary renal cell carcinoma who cannot undergo or decline surgery, percutaneous cryoablation delivered under image guidance offers a treatment that is safe, kidney-preserving, and, on the evidence of five years of follow-up, extraordinarily effective. The authors suggest that when treating type 2 tumors, radiologists should aim for larger ablation safety margins to account for their more aggressive biology. As interventional oncology continues to mature, they argue, cryoablation for renal cell carcinoma, particularly for indolent histologic subtypes like papillary tumors, deserves increased consideration in clinical practice and in future guideline development. For a disease increasingly caught early by incidental imaging, the freezer may prove to be as mighty as the scalpel.

Subject of Research: Percutaneous cryoablation as a treatment for papillary renal cell carcinoma

Article Title: Safety and oncologic efficacy of percutaneous cryoablation of papillary renal cell carcinoma: a 5-year single-center follow-up study

Article References: Mulot, B.-M., de Marini, P., Tan, A. S. M., Orkut, S., Garnon, J., Weiss, J., Autrusseau, P. A., Tricard, T., Lang, H., Cazzato, R. L., & GANGI, A. (2025). Safety and oncologic efficacy of percutaneous cryoablation of papillary renal cell carcinoma: a 5-year single-center follow-up study. CVIR Oncology, 1(1), Article 4. https://doi.org/10.1007/s44343-025-00003-5

Image Credits: AI Generated

DOI: 10.1007/s44343-025-00003-5

Keywords: cryoablation, papillary renal cell carcinoma, kidney cancer, interventional radiology, renal tumors, minimally invasive treatment, oncology, MRI guidance, CT guidance, cancer survival, thermal ablation, nephron-sparing