In a study reported in the Journal of Clinical Oncology, Xu et al found that higher levels of preoperative plasma kidney injury molecule-1 (pKIM-1) distinguished renal cell carcinoma from benign renal masses.
As stated by the investigators, “Both clear cell and papillary renal cell carcinoma overexpress kidney injury molecule-1. We investigated whether pKIM-1 may be a useful risk stratification tool among patients with suspicious renal masses.”
Study Details
In the study, prenephrectomy pKIM-1 was measured in two cohorts of patients with suspicious renal masses. Cohort 1, from the prospective K2 trial, included 162 patients found to have clear cell renal cell carcinoma and 162 patients with benign renal masses; Cohort 2 included 247 patients with small (cT1a) renal masses from the Johns Hopkins Brady Urological Institute Biorepository, with 184 having renal cell carcinoma.
Key Findings
pKIM-1 levels were higher in patients with renal cell carcinoma vs those with benign renal masses, with odds ratios (ORs) of 1.63 per log increase in pKIM-1 (95% confidence interval [CI] = 1.43–1.85, P < .001) in Cohort 1 and 3.11 per log increase in pKIM-1 (95% CI = 2.02–4.79, P < .001) in Cohort 2.
pKIM-1 distinguished renal cell carcinoma vs benign masses with an area under the receiver operating curve (AUC) value of 0.81 (95% CI = 0.76–0.86) in Cohort 1 and an AUC value of 0.74 (95% CI = 0.67–0.80) in Cohort 2. The addition of pKIM-1 level to an established nomogram (Lane nomogram) for predicting malignancy improved the AUC value from 0.65 (95% CI = 0.57–0.74) to 0.78 (95% CI = 0.72–0.85).
A pKIM-1 cutpoint derived from analysis in Cohort 2 exhibited sensitivity of 92.5% and specificity of 60% in identifying renal cell carcinoma in Cohort 1.
In long-term follow-up of renal cell carcinoma cases in Cohort 1, multivariate analysis showed that higher prenephrectomy pKIM-1 was associated with poorer metastasis-free survival (hazard ratio [HR] = 1.29 per log increase in pKIM-1, 95% CI = 1.10–1.53) and overall survival (HR = 1.31 per log increase in pKIM-1, 95% CI = 1.10–1.54).
No metastatic events were observed in the long-term follow-up of Cohort 2; as noted by the investigators, this finding is consistent with the favorable prognosis of resected cT1a renal cell carcinoma.
The investigators concluded, “Among patients with renal masses, pKIM-1 is associated with malignant pathology, worse metastasis-free survival, and risk of death. pKIM-1 may be useful for selecting patients with renal masses for intervention vs surveillance.”
Wenxin Xu, MD, of Dana-Farber Cancer Institute, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported in part by Congressionally Directed Medical Research Programs, National Institutes of Health, and National Cancer Institute. For full disclosures of the study authors, visit ascopubs.org.
