Assessing the accuracy of endoscopic estimates of lesion size in urology using in vitro models of the urinary tract

Long-term Recurrence Rates of Low-risk Non-muscle-invasive Bladder Cancer-How Long Is Cystoscopic Surveillance Necessary?

BACKGROUND

While low-risk non-muscle-invasive bladder cancer (LR-NMIBC) has a low propensity to progress, the risk of recurrence remains high (50% within 4 yr). Guidelines recommend cystoscopic surveillance after resection, but the necessary duration of follow-up is debated.

OBJECTIVE

To determine the risk of recurrence beyond 5 yr after diagnosis in patients with LR-NMIBC, and to identify risk factors of recurrence.

DESIGN, SETTING, AND PARTICIPANTS

In this multicenter retrospective observational study, patients who received their first transurethral bladder tumor resection before 2016 for LR-NMIBC were included. Low risk was defined as a primary, solitary, low grade, Ta bladder tumor measuring <3 cm.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary endpoint was determination of the recurrence rates at 1, 2, and 5 yr. The secondary endpoints included overall recurrence-free survival (RFS) and high-risk RFS. A univariate analysis and multivariable logistic regression were performed to assess the risk factors for recurrence over the study period.

RESULTS AND LIMITATIONS

The median age of the 577 patients was 70.9 yr, and 126 (21.8%) patients were female. The median follow-up was 69.6 (interquartile range: 58.4) mo, and recurrence was observed in 236 (40.9%) patients. The 1-, 2-, and 5-yr RFS rates were 81.6% (95% confidence interval 78.4-84.9), 72.4% (68.7-76.3), and 59.2% (55-63.8), respectively. Recurrence after 5 yr was observed in 13.1% (28/213). High-risk recurrence, defined as the first recurrence of a high-grade and/or ≥T1 tumor, occurred in 6.2% (36/579) overall and 2.8% (6/213) after 5 yr. The lack of a single postoperative dose of chemotherapy and tumor size >2 cm were prognostic factors of recurrence.

CONCLUSIONS

The risk of recurrence in patients with LR-NMIBC decreases progressively after the 1st year and remains low beyond 5 yr. Discontinuation of endoscopic surveillance after 5 yr in patients with LR-NMIBC can be discussed. Treatment with postoperative chemotherapy and tumor size <2 cm may be relevant variables to identify patients who will benefit from cystoscopic follow-up as short as 12 mo.

PATIENT SUMMARY

In this study, we observed that 13% of patients who did not have a recurrence during the first 5 yr following the diagnosis of low-risk non-muscle-invasive bladder cancer will recur after this time point. Discontinuation of cystoscopic surveillance can be discussed after 5 yr in these patients.

Stone size on endoscopic view as a predictor of successful stone retrieval during flexible ureteroscopy: an in vitro analysis

PURPOSE

Basketing plays an important role during flexible ureteroscopy, but it can be time-consuming, especially when fragments are too large to pass through the ureteral access sheath. We aim to present the optimal on-screen, endoscopic stone size that predicts successful basketing through various access sheaths.

METHODS

A tipless basket, individually extended to 5 mm from multiple ureteroscopes: (Flex-Xc, Karl Storz; Flex-X2s, Karl Storz; LithoVue, Boston Scientific; or URF-P6R, Olympus) and via differently sized access sheaths (10-12 Fr through 13-15 Fr), was used in retrieval attempts of various artificial stone sizes (2 mm through 5 mm). A relative endoscopic stone size was recorded as the stone's maximum diameter on endoscopic view compared to the total image diameter.

RESULTS

Basketing of stones up to 2.5 mm, yielding relative endoscopic stone sizes of 0.38 (Flex-Xc), 0.30 (Flex-X2s), 0.32 (LithoVue), and 0.34 (URF-P6R), was successful using all access sheaths. Only the 12-14 Fr and greater sheaths allowed for successful basketing of 3 mm stones. Larger stones did not successfully pass through any of the access sheaths.

CONCLUSION

Successful stone retrieval can be predicted by estimating the stone's size on screen, which is influenced by the type of flexible ureteroscope and access sheath. In our testing, stones of approximately one-third of the screen size passed successfully in all cases.

Integrated Multipoint-Laser Endoscopic Airway Measurements by Transoral Approach

Objectives. Optical and technical characteristics usually do not allow objective endoscopic distance measurements. So far no standardized method for endoscopic distance measurement is available. The aim of this study was to evaluate the feasibility and accuracy of transoral airway measurements with a multipoint-laser endoscope. Methods. The semirigid endoscope includes a multipoint laser measurement system that projects 49 laser points (wavelength 639 nm, power < 5 mW) into the optical axis of the endoscopic view. Distances, areas, and depths can be measured in real-time. Transoral endoscopic airway measurements were performed on nine human cadavers, which were correlated with CT measurements. Results. The preliminary experiment showed an optimum distance between the endoscope tip and the object of 5 to 6 cm. There was a mean measurement error of 3.26% ± 2.53%. A Spearman correlation coefficient of 0.95 (p = 0.01) was calculated for the laryngeal measurements and of 0.93 (p < 0.01) for the tracheal measurements compared to the CT. Using the Bland-Altman-Plot, the 95% limits of agreement for the laryngeal measurements were satisfactory: −0.76 and 0.93. Conclusions. Integrated multipoint-laser endoscopic measurement is a promising technical supplement, with potential use in diagnostic endoscopy and transoral endoscopic surgery in daily practice.