Safety and efficacy of Symani robotic-assisted microsurgery: Assessment of vascular anastomosis patency, thrombus, and stenosis in a randomized preclinical study.

INTRODUCTION: The Symani surgical system undergoes scrutiny in this study as part of a series of preclinical investigations. Previous studies compared the precision of robotic-assisted anastomoses with manual techniques. This study aimed to evaluate the critical, histological, and gross parameters at the site of anastomosis and at distant sites in a rat model to provide insights into the safety and efficacy of robotic-assisted microsurgery to enhance its potential for clinical adoption. MATERIALS AND METHODS: Experienced microsurgeons performed arterial and venous anastomoses in 16 Wistar rats, randomized into four treatment groups: robotic artery, robotic vein, manual artery, and manual vein. Various parameters were evaluated at two time points (T0 and T30) on the day of the procedure and at Day 28 (T28d). In the second phase of the study, the animals underwent necropsy, histopathologic analysis, micro-CT scans, and angiography imaging of the anastomosis sites, major organs, and distant target organs by a blinded assessor. RESULTS: Patency rates were 100% at T0 and T30 for all anastomoses and stayed at 100% on T28d for the robotic subgroups; however, it decreased to 87.5% for manual arterial anastomoses owing to a case of obstructive thrombus. No evidence of clot migration was observed. Blood flow parameters and procedure times did not differ significantly. The blinded semiquantitative histological analysis revealed no significant disparities between the robotic and manual anastomoses across various pathological indicators. No gross abnormalities were detected in musculoskeletal examinations. CONCLUSION: This preclinical study demonstrated the safety of the Symani surgical system. Results suggest equivalence between robotic and manual techniques regarding thrombus formation at the anastomotic site and distal organs.

Modest agreement between magnetic resonance and pathological tumor regression after neoadjuvant therapy for rectal cancer in the real world.

Magnetic resonance imaging (MRI) is routinely used for preoperative tumor staging and to assess response to therapy in rectal cancer patients. The aim of our study was to evaluate the accuracy of MRI based restaging after neoadjuvant chemoradiotherapy (CRT) in predicting pathologic response. This multicenter cohort study included adult patients with histologically confirmed locally advanced rectal adenocarcinoma treated with neoadjuvant CRT followed by curative intent elective surgery between January 2014 and December 2019 at four academic high-volume institutions. Magnetic resonance tumor regression grade (mrTRG) and pathologic tumor regression grade (pTRG) were reviewed and compared for all the patients. The agreement between radiologist and pathologist was assessed with the weighted k test. Risk factors for poor agreement were investigated using logistic regression. A total of 309 patients were included. Modest agreement was found between mrTRG and pTRG when regression was classified according to standard five-tier systems (k = 0.386). When only two categories were considered for each regression system, (pTRG 0-3 vs pTRG 4; mrTRG 2-5 vs mrTRG 1) an accuracy of 78% (95% confidence interval [CI] 0.73-0.83) was found between radiologic and pathologic assessment with a k value of 0.185. The logistic regression model revealed that "T3 greater than 5 mm extent" was the only variable significantly impacting on disagreement (OR 0.33, 95% CI 0.15-0.68, P = .0034). Modest agreement exists between mrTRG and pTRG. The chances of appropriate assessment of the regression grade after neoadjuvant CRT appear to be higher in case of a T3 tumor with at least 5 mm extension in the mesorectal fat at the pretreatment MRI.

Early age of onset is an independent predictor for worse disease-free survival in sporadic rectal cancer patients. A comparative analysis of 980 consecutive patients.

BACKGROUND: while interest on early-onset colorectal cancer (age ≤49) is on the rise, studies on early-onset rectal cancer (EORC) are limited. The aim of this study was to compare predictors for disease progression/recurrence between sporadic EORC and late-onset RC patients (LORC). METHODS: 163 EORC and 830 LORC operated between January 1st, 2010 and April 30th, 2021 at a tertiary center were included. Demographics, tumor characteristics, microsatellite status, gene mutations (KRAS, BRAF, NRAS, PI3Kca) and oncologic outcomes were compared. A Cox proportional hazards regression analysis was performed to ascertain the effect of variables on recurrence/progression and death. Recurrence/Progression free survival (R/PFS) and cancer specific survival (CSS) were analyzed by the Kaplan-Meier estimator. RESULTS: Mean age of EORC was 42.16, (46% aged 45-49). A majority of EORC patients had a family history for CRC (p = 0.01) and underwent total neoadjuvant treatment (p = 0.01). EORC patients showed a higher rate of low-grade tumor differentiation (p < 0.0001), stage III-IV (p = 0.001), microsatellite instability (p = 0.02), locoregional nodal (p = 0.001) and distant metastases (p < 0.0001). Accordingly, more EORC patients underwent adjuvant treatment (p < 0.0001). Mutations were mostly reported among LORC cases (p = 0.04), whereas EORC patients showed a worse R/PFS (p = 0.02), even at stage I (p = 0.04). CSS did not differ (p = 0.11) across groups. Multivariate analysis indicated age of onset (p = 0.04) was an independent predictor for progression/recurrence. CONCLUSIONS: Age of onset was shown to be an independent unfavorable predictor. Delayed diagnosis could explain this effect in the more advanced stages, while the worse outcomes in stage I may suggest a more aggressive disease behavior.