Towards rational post-nephrectomy follow-up guidelines in RCC

Systematic Review and STARD Scoring of Renal Cell Carcinoma Circulating Diagnostic Biomarker Manuscripts

Background

No validated molecular biomarkers exist to help guide diagnosis of renal cell carcinoma (RCC) patients. We seek to evaluate the quality of published RCC circulating diagnostic biomarker manuscripts using the Standards for Reporting of Diagnostic Accuracy Studies (STARD) guidelines.

Methods

The phrase “(renal cell carcinoma OR renal cancer OR kidney cancer OR kidney carcinoma) AND circulating AND (biomarkers OR cell free DNA OR tumor DNA OR methylated cell free DNA OR methylated tumor DNA)” was searched in Embase, MEDLINE, and PubMed in March 2018. Relevant manuscripts were scored using 41 STARD subcriteria for a maximal score of 26 points. All tests of statistical significance were 2 sided.

Results

The search identified 535 publications: 27 manuscripts of primary research were analyzed. The median STARD score was 11.5 (range = 7-16.75). All manuscripts had appropriate abstracts, introductions, and distribution of alternative diagnoses. None of the manuscripts stated how indeterminant data were handled or if adverse events occurred from performing the index test or reference standard. Statistically significantly higher STARD scores were present in manuscripts reporting receiver operator characteristic curves (P < .001), larger sample sizes (P = .007), and after release of the original STARD statement (P = .005).

Conclusions

Most RCC circulating diagnostic biomarker manuscripts poorly adhere to the STARD guidelines. Future studies adhering to STARD guidelines may address this unmet need.

Comprehensive long-term assessment of outcomes following robot-assisted partial nephrectomy for renal cell carcinoma: the ROMe's achievement and its predicting nomogram

BACKGROUND

We proposed a new tool (named ROMe's) to summarize long-term outcomes after partial nephrectomy (PN), identified its predictors and generated a predicting nomogram.

METHODS

A retrospective analysis of a multicenter dataset of patients with non-metastatic pT1-3a renal cell carcinoma was performed. Baseline demographic, clinical, pathologic and perioperative data were collected. ROMe's was defined as the concomitant lack of cancer-recurrences, death and newly onset Chronic Kidney Disease (CKD), at long term follow-up. Kaplan-Meier method investigated the predictive role of Trifecta on ROMe's achievement. Univariable and multivariable Cox regression analyses identified its predictors. A nomogram was generated and its accuracy was quantified using concordance index (CI). A calibration plot was obtained with 200 bootstraps resampling to explore nomogram performance at 5 years and decision curve analyses (DCA) assessed the net benefit of the model at 12, 36 and 60 months.

RESULTS

We included 927 patients. The rates of ROMe's were 82%, 72% and 56% at 1, 3 and 5 years follow-up. At Kaplan-Meier analysis, patients who achieved Trifecta displayed a significantly higher probability of ROMe's (log rank P<0.001). Young age (OR=0.982; P=0.001), low RENAL score (OR=0.86; P=0.037), high preoperative filtration rate (OR=1.02; P<0.001) and Trifecta achievement (OR=2.03; P=0.015), were independent predictors of ROMe's. The nomogram showed a CI of 0.76 at 60 months. The 5-years calibration plot confirmed a good discrimination accuracy (0.74); on DCA, the net benefit of using the model was evident for probabilities >30%.

CONCLUSIONS

We conceived a triad to summarize the main long-term oncologic and functional outcomes after PN and generated a predicting nomogram.

MicroRNAs in Serum Exosomes as Potential Biomarkers in Clear-cell Renal Cell Carcinoma

BACKGROUND

Circulating microRNAs (miRNAs) in exosomes are emerging as clinically useful tools for cancer detection. However, little is known about their diagnostic impact in clear-cell renal cell carcinoma (ccRCC).

OBJECTIVE

To investigate whether miRNAs in serum exosomes can serve as biomarkers in ccRCC.

DESIGN, SETTING, AND PARTICIPANTS

Serum samples were obtained from 82 patients with ccRCC and 80 healthy volunteers. Exosomes were extracted and purified to selectively capture exosomes positive for tumor-associated epithelial cell adhesion molecule (EpCAM) via a magnetic bead technique. Total RNA was extracted and expression levels of miR-210, miR-1233, and miR-15a miRNAs were quantified and normalized to U6 levels.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Expression levels were compared using a Mann-Whitney U-test, Friedman test, or Wilcoxon test. Receiver operating characteristic (ROC) curves were plotted to assess the diagnostic value of exosomal miRNAs for differentiation between ccRCC patients and controls.

RESULTS AND LIMITATIONS

Expression levels of exosomal miR-210 and miR-1233 were significantly higher in ccRCC patients than in healthy individuals (both p<0.01). No significant difference was observed for exosomal miR-15a. Exosomal miR-210 and miR-1233 expression levels in different TNM stages were significantly higher than in the controls (all p<0.01). Exosomal miR-210 and miR-1233 expression levels were significantly lower in postoperative than in preoperative samples (both p<0.01). ROC analysis demonstrated that exosomal expression levels distinguished ccRCC patients from healthy individuals with 70% sensitivity and 62.2% specificity for miR-210, and 81% sensitivity and 76% specificity for miR-1233. The retrospective design and lack of other tumor subtypes are limitations of the study.

CONCLUSIONS

Serum exosomal miRNAs might represent potential diagnostic biomarkers in ccRCC in the future.

PATIENT SUMMARY

Circulating levels of exosomal microRNAs miR-210 and miR-1233 have potential as biomarkers for diagnostic and monitoring purposes in renal cancer in the future. These molecules can be measured in serum in so-called liquid biopsy.