Kidney cancer research advances while major evidence gaps persist

A 23-article research collection on kidney cancer documents advances in molecular classification, risk prediction, systemic therapy and management of uncommon tumors, while revealing that prevention, early detection and prospective validation remain poorly studied. The collection, published as an editorial in Frontiers in Oncology, brings together nine original research articles, one systematic review, two reviews and 11 case reports contributed by teams from multiple countries. Its scope covers renal cell carcinoma and rarer renal or urinary-tract malignancies. An estimated 434,000 new kidney cancer cases and 156,000 deaths occurred worldwide in 2022, according to GLOBOCAN estimates cited by the editors, and more than 30% of patients with renal cell carcinoma are diagnosed with metastatic disease.

The strongest evidence in the collection concerns systemic treatment for advanced disease. Immune checkpoint inhibitors, used alone or with vascular endothelial growth factor receptor tyrosine kinase inhibitors, have changed care for advanced renal cell carcinoma, while a 2022 World Health Organization classification introduced molecularly defined tumor categories. Real-world experience with first-line nivolumab plus cabozantinib reinforces the approach without reproducing the controlled conditions of a pivotal trial. In the ARON-1 series, 333 patients were treated at 52 centers in 17 countries, including people with poor performance status, non-clear cell histology or brain metastases who are often excluded from clinical trials. Estimated two-year overall survival was 75% and objective response rate was 58%, broadly consistent with the pivotal trial. Grade 3 or higher toxicity occurred in 37%, although the authors cautioned that less systematic adverse-event reporting in routine practice could help explain the lower figure.

Real-world treatment data also show why survival associations require careful interpretation. In 96 patients receiving first-line sunitinib at one institution, multi-organ toxicity affected 81%. Cardiovascular toxicity and dose reductions for cardiovascular, hematologic or gastrointestinal toxicity were associated with longer survival, leading the authors to suggest that some toxicities may reflect treatment efficacy. That hypothesis remains unproven: retrospective analyses can make treatment toxicities appear favorable when they are more common in patients who remain on therapy long enough for survival to improve. The study therefore cannot establish that tolerating or reducing a dose prolongs survival, and prospective confirmation would be needed before such an approach could influence care. The authors also emphasized the need to balance toxicity against continuity of treatment rather than treating adverse effects as simple markers of success.

Several studies explored ways to estimate prognosis, identify biologically distinct tumors and select treatment for rare histologies. A proposed Renal Immune Prognostic Index combined prealbumin, lymphocyte count and immunoglobulin M in surgical patients and was evaluated in an independent cohort of 350 people. A separate analysis of 81 patients receiving nivolumab in second or later lines found that low Gustave Roussy Immune scores were associated with higher response rates and longer survival. The collection’s only prospective study measured serum proteins and metabolites in 38 patients receiving first-line sunitinib; higher interleukin-6, arginase-1 and S100A9 concentrations predicted shorter survival, while tryptophan–kynurenine metabolism differed between patients with extreme outcomes. These findings generate potentially useful hypotheses, but prognostic signatures derived from small, retrospective cohorts require prospective and external validation, particularly in patients receiving current first-line combinations.

Laboratory research offers another route toward more precise treatment. In renal cell carcinoma cell lines and mouse xenografts, overexpressing BNIP3, a hypoxia-regulated pro-apoptotic protein, reduced proliferation and invasion and increased apoptosis through hypoxia-inducible factor 1α-dependent autophagy. Separately, an analysis combining transcriptomic data from five clear cell renal cell carcinoma cohorts with obesity-related adipose profiles and machine learning identified FCGR2A, found in single-cell data in M2-polarized macrophages, as a possible link between obesity and tumor biology. An ammonia-metabolism risk score was also derived from public data and tested in external and immunotherapy cohorts, with laboratory silencing of CSAD reducing migration and invasion in four cell lines. These studies identify testable mechanisms, but their reliance on retrospective datasets and preclinical models means they do not yet establish clinical value or patient benefit.

Diagnosis continues to depend on imaging, pathology and increasingly sophisticated molecular analysis. A review of deep learning across renal ultrasound examined segmentation, volumetry, functional prediction and disease diagnosis, reporting performance in some tasks that approached specialist-level recognition of structures or lesions. The authors identified data quality, interpretability, generalization across devices and integration into clinical workflows as major barriers. Because the review covered kidney disease broadly rather than kidney cancer alone, its potential for earlier cancer detection remains illustrative rather than demonstrated. Imaging can also produce false certainty. One case involved a 1.6-centimeter enhancing nodule that was removed as presumed renal cell carcinoma but proved to be ectopic adrenal tissue, while another described an epithelial-type Wilms tumor in a 23-year-old woman with a large renal mass. These cases illustrate why histopathology remains decisive when a renal mass does not fit the expected pattern.

Genomic findings are refining renal tumor classification and may influence both treatment and family management. Reports on papillary renal neoplasm with reverse polarity, a recently characterized KRAS-associated tumor with generally indolent behavior, described only about 100 published cases and showed that the entity’s classification is still evolving. One report described its synchronous occurrence with a genetically distinct multilocular cystic renal neoplasm of low malignant potential in one kidney, with no recurrence at nine months. Another study identified a novel TCEB1 p.V73E variant in ELOC-mutant renal cell carcinoma using next-generation and Sanger sequencing. Separate cases of VHL-deficient renal cell carcinoma were managed with radiofrequency ablation, partial nephrectomy and pazopanib, raising questions about genetic testing and screening relatives. Accurate molecular diagnosis matters because indolent tumors may be managed with nephron-sparing surgery, whereas hereditary syndromes require attention beyond the individual patient.

The rare tumors highlighted in the collection expose the limits of evidence-based care. Collecting duct carcinoma is an aggressive subtype in which most patients present with metastatic disease; one 66-year-old man with hematuria declined systemic therapy for financial reasons after nephrectomy and was alive at 13 months. A renal medullary carcinoma diagnosed during pregnancy was treated with doxorubicin, cyclophosphamide and weekly paclitaxel because checkpoint inhibitors and antiangiogenic agents are resistant in that tumor. The regimen produced tumor shrinkage, permitted delivery of a healthy infant at 33 weeks and was followed by chemoradiation, with the patient alive two years after diagnosis. Other reports described a renal leiomyosarcoma with inferior vena cava tumor thrombus that progressed despite nephrectomy and adjuvant chemotherapy, and mucinous adenocarcinoma of the renal pelvis arising amid chronic stones and xanthogranulomatous pyelonephritis. Circulating tumor DNA and serum markers signaled recurrence of the latter while imaging remained nonspecific, and its adjuvant chemotherapy was borrowed from colorectal cancer guidance because no renal-specific protocol exists.

Local treatment and unusual disease patterns further complicate clinical decisions. A systematic review of 13 studies involving nonsystemic treatment for metastatic renal cell carcinoma found that complete metastasectomy was associated with better overall and progression-free survival than incomplete or no metastasectomy, while stereotactic body radiotherapy provided palliation and durable disease control. These observational findings came from selected patients and identify possible subjects for prospective trials rather than establish a treatment standard. In 37 cases of spontaneous renal cell carcinoma rupture treated over ten years at one center, five-year cancer-specific survival was 80.1% and progression-free survival was 68.8%. Stage, grade, tumor size, perirenal fat invasion and coagulation abnormalities were associated with outcomes in univariate analyses, whereas the timing and type of surgery were not. A separate case of clear cell renal cell carcinoma with synchronous contralateral ureteral metastasis, a presentation the authors said had been described in fewer than ten patients, was managed with staged partial nephrectomy and nephroureterectomy, with no metastasis evident at 14 months.

Across the collection, the clearest priority is to turn promising signals into prospectively tested improvements in prevention and care. Only one of the 23 studies was prospective, and most were retrospective, small or limited to individual patients. Except for an obesity-related analysis and discussion of familial screening in VHL disease, none directly examined modifiable risk, population screening or awareness interventions, even though obesity, hypertension and smoking are established kidney cancer risk factors. The editors call for prospective studies of artificial-intelligence-assisted imaging, inexpensive biomarkers and risk-adapted follow-up of incidentally detected masses. Rare disease also requires shared infrastructure, including registries, molecular profiling, molecular tumor boards and, where appropriate, circulating tumor DNA monitoring. The collection’s progress is therefore substantial but uneven: advanced treatment and molecular classification are advancing, while prevention, early detection, quality-of-life measurement, treatment access and validation of prognostic signatures remain the hardest gaps to close.

Subject of Research: Advances and evidence gaps in kidney cancer prevention, diagnosis and treatment

Article Title: Editorial: Kidney cancer awareness month 2025: current progress and future prospects on kidney cancer prevention, diagnosis and treatment

Article References: Mottaran, A., Sfakianos, J. P., Flaifel, A., & Margulis, V. (2026). Editorial: Kidney cancer awareness month 2025: current progress and future prospects on kidney cancer prevention, diagnosis and treatment. Frontiers in Oncology, 16, Article 2018903. https://doi.org/10.3389/fonc.2026.2018903

Image Credits: AI Generated

DOI: 10.3389/fonc.2026.2018903

Keywords: kidney cancer, renal cell carcinoma, molecular classification, immunotherapy, cancer biomarkers, medical imaging, rare renal tumors, clinical trials, treatment outcomes, Editorial, Kidney, cancer