Collateral vessels on CT signal aggressive kidney tumors but add little beyond stage, study finds

Collateral vessels visible on preoperative computed tomography scans appear in nearly half of patients undergoing surgery for renal cell carcinoma, and their presence is linked to larger, more aggressive tumors and more complex operations, according to a retrospective study published in BMC Urology. However, after accounting for tumor stage, the vessels themselves offered no independent prognostic or surgical information in this cohort.

Researchers led by Melih Senkol analyzed 128 patients who underwent partial or radical nephrectomy for renal cell carcinoma between January 2019 and November 2024. The team reviewed contrast-enhanced CT images taken before surgery, recording whether collateral vessels were present, how many there were, and their diameter. Patients were then compared across clinical, surgical, radiological, and pathological parameters, including nephrometry and prognostic scoring systems.

Collateral vessels were detected in 48.4 percent of the patients. Their presence was significantly associated with larger tumor size and volume, irregular tumor margins, advanced T stage, and high nuclear grade, with all of these comparisons reaching p < 0.001. Patients whose scans showed collateral vessels were also more symptomatic, with hematuria and flank pain reported more frequently in this group.

The surgical picture differed as well. Patients with collateral vessels more often underwent radical rather than partial nephrectomy and open rather than minimally invasive surgery, with p values of less than 0.001 and 0.001 respectively. This group also experienced a greater postoperative hemoglobin decrease and higher complication rates, reported at p < 0.001 and p = 0.016.

Several adverse pathological features clustered with collateral vessel presence. Lymphovascular invasion and tumor necrosis were both more common in these patients at p < 0.001, and perineural invasion was more frequent at p = 0.002.

Standardized scoring systems reinforced the pattern. Nephrometry measures including RENAL and PADUA, along with MAP, SSIGN, and UISS scores, were all significantly higher among patients with collateral vessels, each at p < 0.001. The E-PASS comprehensive risk score was also higher in this group at p = 0.022.

The key caveat emerged when the researchers applied T-stage-adjusted regression models. After adjustment for pathological T stage, collateral vessel presence was no longer independently associated with these outcomes. In other words, the vessels appear to be a marker of tumors that are already more advanced rather than a source of new prognostic information on their own, at least within this cohort of 128 patients.

Among the subgroup of patients who did have collateral vessels, however, one measurement retained its value. Vessel diameter remained associated with RENAL and PADUA scores, tumor size, SSIGN score, and the extent of resection, though not with perioperative morbidity. The authors suggest that vessel diameter may be a more informative parameter of anatomical tumor complexity than simple presence or absence, and they call for prospective validation of this observation.

The study is retrospective and limited to a single cohort of 128 patients operated on over roughly five years, so the findings describe associations within that population rather than causal effects or validated predictive rules. The article was published as an open-access paper on 26 October 2026 and, as an early-release version, remains subject to further editorial revisions before the final version of record.

Subject of Research: The association between collateral vessels seen on preoperative CT and tumor biology, surgical complexity, and prognosis in renal cell carcinoma.

Article Title: Prognostic significance of collateral vessels detected by preoperative computed tomography in renal tumors: association with surgical, pathological, and radiological parameters

Article References: Senkol, M., Yazar, V. M., Coskun, H., & Gercek, O. (2026). Prognostic significance of collateral vessels detected by preoperative computed tomography in renal tumors: association with surgical, pathological, and radiological parameters. BMC Urology. https://doi.org/10.1186/s12894-026-02449-y

Image Credits: AI Generated

DOI: 10.1186/s12894-026-02449-y

Keywords: renal cell carcinoma, collateral vessels, computed tomography, nephrectomy, nephrometry, SSIGN score, tumor stage, lymphovascular invasion, surgical complexity, prognosis, BMC Urology, Prognostic