Pathologic Characteristics of Exophytic Renal Masses

Single-Site Sutureless Partial Nephrectomy for Small Exophytic Renal Tumors

Partial nephrectomy (PN) is the standard procedure for most patients with localized renal cancer. Laparoscopy has become the preferred surgical approach to target this cancer, but the steep learning curve with laparoscopic PN (LPN) remains a concern. In LPN intracorporeal suturing, the operation time is further extended even under robot assistance, a step which prolongs warm ischemic time. Herein, we shared our experience to reduce the warm ischemia time, which allows surgeons to perform LPN more easily by using a combination of hemostatic agents to safely control parenchymal bleeding. Between 2015 and 2018, we enrolled 52 patients who underwent LPN in our hospital. Single-site sutureless LPN and traditional suture methods were performed in 33 and 19 patients, respectively. Preoperative, intra-operative, and postoperative variables were recorded. Renal function was evaluated by estimated glomerular filtration rate (eGFR) pre- and postoperatively. The average warm ischemia time (sutureless vs. suture group; 11.8 ± 3.9 vs. 21.2 ± 7.2 min, p < 0.001) and the operation time (167.9 ± 37.5 vs. 193.7 ± 42.5 min, p = 0.035) were significantly shorter in the sutureless group. In the sutureless group, only 2 patients suffered from massive urinary leakage (>200 mL/day) from the Jackson Pratt drainage tube, but the leakage spontaneously decreased within 7 days after surgery. eGFR and serum hemoglobin were not found to be significantly different pre- and postoperatively. All tumors were removed without a positive surgical margin. All patients were alive without recurrent tumors at mean postoperative follow-ups of 29.3 ± 12.2 months. Single-site sutureless LPN is a feasible surgical method for most patients with small exophytic renal cancer with excellent cosmetic results without affecting oncological results.

New Preoperative Nomogram Using the Centrality Index to Predict High Nuclear Grade Clear Cell Renal Carcinoma

Objective

Nuclear grading is an independent prognosis factor of clear-cell renal cell carcinoma (ccRCC). A non-invasive preoperative predictive WHO/International Society of Urologic Pathology (WHO/ISUP) grading of ccRCC model is needed for clinical use. The anatomical complexity scoring system can span a variety of image modalities. The Centrality index (CI) is a quantitatively anatomical score commonly used for renal tumors. The purpose of this study was to develop a simple model to predict WHO/ISUP grading based on CI.

Materials and methods

The data in this study were from 248 ccRCC patients from five hospitals. We developed three predictive models using training data from 167 patients: a CI-only model, a valuable clinical parameter model and a fusion model of CI with valuable clinical parameters. We compared and evaluated the three models by discrimination, clinical usefulness and calibration, then tested them in a set of validation data from 81 patients.

Results

The fusion model consisting of CI and tumor size (valuable clinical parameter) had an area under the curve (AUC) of 0.82. In the validation set, the AUC was 0.85. The decision curve showed that the model had a good net benefit between the threshold probabilities of 5–80%. And the calibration curve showed good calibration in the training set and validation set.

Conclusion

This study confirms that CI is associated with the WHO/ISUP grade of ccRCC, and the possibility that a bivariate model incorporating tumor size may help urologist’s evaluation patients’ prognostic.

RENAL nephrometry score is a predictive factor for the annual growth rate of renal mass

OBJECTIVE

To evaluate the association between the RENAL nephrometry score and annual growth rates of renal masses presumed to be renal cell carcinoma.

METHODS

The current study included 47 renal tumors followed up for at least 12 months, of which 26 tumors were found to be pathologically proven renal cell carcinomas. Annual tumor growth rates were calculated from changes in the maximal diameter on computed tomography, and RENAL nephrometry scores were recorded on initial imaging by two senior urologists. The associations between clinical characteristics including the RENAL nephrometry score and annual growth rates were analyzed using a linear regression model.

RESULTS

The median tumor size at diagnosis was 1.7 cm (range 0.6-5.8). The median nephrometry score at diagnosis was 7 (range 4-10). Overall, the median tumor growth rate was 0.34 cm per year (range -0.19-2.0). Linear regression analysis showed that the annual tumor growth rate was associated with the RENAL nephrometry score (P < 0.0001), but it was independent of the age at diagnosis, sex and initial tumor size. In addition, the correlation between the RENAL nephrometry score and annual growth rate remained significant in the 26 pathologically proven renal cell carcinomas.

CONCLUSIONS

The RENAL nephrometry score is associated with the annual growth rate of renal masses. Our findings further support the association between the RENAL nephrometry score and tumor biology.

Watchful waiting in the treatment of the small renal mass

Objectives:

To evaluate the role and feasibility of observation with regard to the small renal mass.

Methods:

We performed a literature search of MEDLINE, reviewing the world literature relevant to the natural history, role of percutaneous biopsy and surveillance of the small renal mass.

Results:

The average yearly growth rate of most small renal masses ranges from 0.1 to 0.70 cm/yr with obvious exceptions. Clinical predictors of growth such as radiographic size at presentation, age, gender and tumor characteristics are not reliable. Approximately 1% develops metastatic disease while under surveillance. Contemporary series of percutaneous biopsy of small renal masses report sensitivity for malignancy to be 90%-98%. However, false-negative results can occur. For the majority of patients, the gold standard remains surgical extirpation.

Conclusions:

Watchful waiting is an acceptable option for management of small renal masses in the surgically unfit and elderly population. More information regarding the natural history and metastatic potential of small renal masses is needed. Percutaneous needle biopsy can be successful in detecting malignancy in selected patients with small renal masses. The role of needle biopsy for the small renal mass continues to evolve