ABSTRACT
BACKGROUND: En bloc resection of bladder tumor (ERBT) is an established surgical treatment method for patients with non-muscle invasive bladder cancer (NMIBC) in tumors less than 3 cm. Data regarding the efficacy and safety of ERBT on larger than 3 cm tumors are sparse and its efficacy compared to conventional transurethral resection (TURBT) remains unclear. The aim of this study was to prospectively compare the feasibility, safety and oncological outcomes of laser (Tm-fiber) ERBT and TURBT in patients with primary bladder lesions ≥3 cm. METHODS: A cohort of 45 patients who underwent surgery for primary NMIBC between February 2018 and March 2022 was collected prospectively. There was no randomization. All procedures were performed by two experienced surgeons. Inclusion criteria were as follows: age >18 years, primary Ta or T1 bladder tumor with a diameter of ≥3 cm, no more than 3 tumors and no history of upper tract urothelial carcinoma. Exclusion criteria were carcinoma in situ or invasion into muscle layer (≥T2). ERBT was performed with thulium fiber laser (IPG, Russia). Primary endpoints included efficacy with recurrence-free survival (RFS) at 3, 6 and 12 months. Secondary endpoints were safety parameters, perioperative data and specimen quality (the presence of muscle layer in specimens). RESULTS: Twenty-eight patients underwent laser ERBT and 17 conventional TURBT. The location and size of the tumors were comparable in both groups. The success rate was 93.3% in the ERBT group with two cases of conversion from ERBT to TURBT. Detrusor muscle was present in 92.8% patients in the ERBT group versus 70.5% in the TURBT group (P=0.04). Obturator nerve reflex was observed only in the TURBT group: 17.6% vs. 0.0% (P=0.02). The frequency of other complications was comparable between the two groups. RFS was not statistically different between the two methods at 3 (93.9% vs. 94.1%, P=0.87), 6 (89.3% vs. 82.3%, P=0.5) and 12 months (89.3% vs. 70.6%, P=0.11). CONCLUSIONS: Laser ERBT is a feasible and safe procedure to manage bladder tumors larger than 3 cm. While it seems safer than TURBT, its effect on efficacy remains to be assessed in larger trials.
Subject(s)
Cystectomy , Laser Therapy , Urinary Bladder Neoplasms , Humans , Urinary Bladder Neoplasms/surgery , Urinary Bladder Neoplasms/pathology , Urinary Bladder Neoplasms/radiotherapy , Male , Female , Prospective Studies , Aged , Cystectomy/methods , Laser Therapy/methods , Laser Therapy/adverse effects , Laser Therapy/instrumentation , Middle Aged , Treatment Outcome , Tumor Burden , Feasibility Studies , Urethra/surgeryABSTRACT
In the present paper, the cyclic stability of the high-temperature two-way shape memory effect was studied in high-strength Ni50.3Ti32.2Hf17.5 polycrystals after various thermomechanical treatments-training (thermocycling under stress) and stress-induced martensite aging. The effect of training and stress-induced martensite aging on the microstructure, the two-way shape memory effect, and its cyclic stability was determined. It was found out that both thermomechanical treatments induce the high-temperature two-way shape memory effect at T > 373 K, with a strain of 1.5% in tension. The influence of cyclic tests (up to 100 stress-free cycles of cooling/heating) on the two-way shape memory effect strain, the transformation temperatures, and the microstructure was established. Different degradation mechanisms of the two-way shape memory effect were established after thermocycling and stress-induced martensite aging.