Concordance between renal tumour biopsy and robotic-assisted partial and radical nephrectomy histology: a 10-year experience

Tailoring Renal Mass Biopsy: Optimal Core Number and Location Based on Tumor Size for Enhanced Diagnostic Accuracy-A Prospective Ex-Vivo Study

OBJECTIVE

To determine the optimal number and location of biopsy cores in renal masses based on mass size in order to maximize diagnostic accuracy.

METHODS

This observational study included 360 patients with renal masses, who were divided equally into six groups. Each group was matched in terms of mass size [mass size category: ≤ 4 cm (T1a), 4-7 cm (T1b), 7-10 cm (T2a), and >10 cm (T2b)]. Core needle biopsies were taken after resection of the mass in an ex-vivo setting. The masses in the first, second, third, and fourth groups underwent 1, 2, 3, and 4 peripheral biopsies, respectively. The masses in the fifth and sixth groups were subjected to 1 and 2 central biopsies, respectively. The results of the biopsies were compared with permanent histopathology results, and the impact of mass size, number of biopsy cores, and location of biopsies on the accuracy of biopsy results were analyzed.

RESULTS

In T1a and T1b size categories, the most accurate diagnostic results were obtained with three peripheral or two central biopsies. However, in T2a and T2b size categories, the most accurate diagnostic results were obtained with four peripheral or two central biopsies. Histological characteristics of the masses did not have statistically significant effect on the diagnostic accuracy of the biopsies.

CONCLUSION

Our findings demonstrate that for masses ≤7 cm, three peripheral or two central samples provide the highest diagnostic accuracy. For masses larger than 7 cm, four peripheral or two central biopsy cores offer the best diagnostic accuracy.

Development of modified multi-parametric CT algorithms for diagnosing clear-cell renal cell carcinoma in small solid renal masses

OBJECTIVE

To refine the existing CT algorithm to enhance inter-reader agreement and improve the diagnostic performance for clear-cell renal cell carcinoma (ccRCC) in solid renal masses less than 4 cm.

METHODS

A retrospective collection of 331 patients with pathologically confirmed renal masses were enrolled in this study. Two radiologists independently assessed the CT images: in addition to heterogeneity score (HS) and mass-to-cortex corticomedullary attenuation ratio (MCAR), measured parameters included ratio of major diameter to minor diameter at the maximum axial section (Major axis / Minor axis), tumor-renal interface, standardized heterogeneity ratio (SHR), and standardized nephrographic reduction rate (SNRR). Spearman's correlation analysis was performed to evaluate the relationship between SHR and HS. Univariate and multivariate logistic regression analyses were employed to identify independent risk factors and then CT-score was adjusted by those indicators. The diagnostic efficacy of the modified CT-scores was evaluated using ROC curve analysis.

RESULTS

The SHR and heterogeneity grade (HG) of mass were correlated positively with the HS (R = 0.749, 0.730, all P < 0.001). Logistic regression analysis determined that the Major axis / Minor axis (> 1.16), the tumor-renal interface (> 22.3 mm), and the SNRR (> 0.16) as additional independent risk factors to combine with HS and MCAR. Compared to the original CT-score, the two CT algorithms combined tumor-renal interface and SNRR showed significantly improved diagnostic efficacy for ccRCC (AUC: 0.770 vs. 0.861 and 0.862, all P < 0.001). The inter-observer agreement for HG was higher than that for HS (weighted Kappa coefficient: 0.797 vs. 0.722). The consistency of modified CT-score was also superior to original CT-score (weighted Kappa coefficient: 0.935 vs. 0.878).

CONCLUSION

The modified CT algorithms not only enhanced inter-reader consistency but also improved the diagnostic capability for ccRCC in small renal masses.

Phantom study of a fully automatic radioactive seed placement robot for the treatment of skull base tumours

BACKGROUND

Interstitial brachytherapy is a form of intensive local irradiation that facilitates the effective protection of surrounding structures and the preservation of organ functions, resulting in a favourable therapeutic response. As surgical robots can perform needle placement with a high level of accuracy, our team developed a fully automatic radioactive seed placement robot, and this study aimed to evaluate the accuracy and feasibility of fully automatic radioactive seed placement for the treatment of tumours in the skull base.

METHODS

A fully automatic radioactive seed placement robot was established, and 4 phantoms of skull base tumours were built for experimental validation. All the phantoms were subjected to computed tomography (CT) scans. Then, the CT data were imported into the Remebot software to design the preoperative seed placement plan. After the phantoms were fixed in place, navigation registration of the Remebot was carried out, and the automatic seed placement device was controlled to complete the needle insertion and particle placement operations. After all of the seeds were implanted in the 4 phantoms, postoperative image scanning was performed, and the results were verified via image fusion.

RESULTS

A total of 120 seeds were implanted in 4 phantoms. The average error of seed placement was (2.51 ± 1.44) mm.

CONCLUSION

This study presents an innovative, fully automated radioactive particle implantation system utilizing the Remebot device, which can successfully complete automated localization, needle insertion, and radioactive particle implantation procedures for skull base tumours. The phantom experiments showed the robotic system to be reliable, stable, efficient and safe. However, further research on the needle-soft tissue interaction and deformation mechanism of needle puncture is still needed.