Surgical quality assessment for the prospective study of oncologic outcomes after laparoscopic modified complete mesocolic excision for nonmetastatic right colon cancer (PIONEER study).

BACKGROUND: The modified complete mesocolic excision (mCME) procedure for right-sided colon cancer is a tailored approach based on the original complete mesocolic excision (CME) methodology. Limited studies evaluated the safety and feasibility of laparoscopic mCME using objective surgical quality assessments in patients with right colon cancer. The objectives of the PIONEER study were to evaluate oncologic outcomes after laparoscopic mCME and to identify optimal clinically relevant endpoints and values for standardizing laparoscopic right colon cancer surgery based on short-term outcomes of procedures performed by expert laparoscopic surgeons. MATERIALS AND METHODS: This is an ongoing prospective, multi-institutional, single-arm study conducted at five tertiary colorectal cancer centers in South Korea. Study registrants included 250 patients scheduled for laparoscopic mCME with right-sided colon adenocarcinoma (from the appendix to the proximal half of the transverse colon). The primary endpoint was 3-year disease-free survival. Secondary outcomes included 3-year overall survival, incidence of morbidity in the first 4 weeks postoperatively, completeness of mCME, central radicality, and distribution of metastatic lymph nodes. Survival data will be available after the final follow-up date (June 2024). RESULTS: The postoperative complication rate was 12.9%, with a major complication rate of 2.7%. In 87% of patients, central radicality was achieved with dissection at or beyond the level of complete exposure of the superior mesenteric vein. Mesocolic plane resection with an intact mesocolon was achieved in 75.9% of patients, as assessed through photographs. Metastatic lymph node distribution varied by tumor location and extent. Seven optimal clinically relevant endpoints and values were identified based on the analysis of complications in low-risk patients. CONCLUSIONS: Laparoscopic mCME for right-sided colon cancer produced favorable short-term postoperative outcomes. The identified optimal clinically relevant endpoints and values can serve as a reference for evaluating surgical performance of this procedure.

Long-term Complications of Laparoscopic or Robotic Lateral Pelvic Node Dissection After Preoperative Chemoradiotherapy for Locally Advanced Rectal Cancer.

BACKGROUND: Patients with rectal cancer who underwent lateral pelvic node dissection might be at a higher risk of postoperative complications derived from technical complexity. However, little is known regarding the long-term complications after lateral pelvic node dissection. OBJECTIVES: The study aimed to investigate the long-term complications of preoperative chemoradiotherapy, followed by total mesorectal excision with lateral pelvic node dissection for locally advanced rectal cancers. DESIGN: A retrospective analysis of a prospectively collected database. SETTINGS: This study was conducted in a tertiary cancer center. PATIENTS: Patients with rectal cancer who underwent total mesorectal excision with lateral pelvic node dissection after preoperative chemoradiotherapy between 2011 and 2019 were analyzed. All operations were performed via a laparoscopic or robotic approach. MAIN OUTCOME MEASURES: Long-term complications were defined as adverse events that persisted or newly appeared ≥90 days after surgery and could be related to the surgery. RESULTS: A total of 164 patients underwent total mesorectal excision with lateral pelvic node dissection after preoperative chemoradiotherapy. Short-term and long-term complication rates were 36.0% and 36.6%, respectively. Lymphocele was the most common long-term complication (17.7% of patients), and 11.6% had anastomotic leakage with chronic sinus. Of the patients with long-term complications, 20.7% of patients needed readmission for treatment. Of the 29 patients with lymphocele, 13 (41.0%) experienced spontaneous absorption and 11 (37.9%) required surgical or percutaneous catheter drainage or antibiotics use. Multivariate analysis showed pathologic pelvic node metastases ( p = 0.008), and a higher number of unilateral harvested pelvic nodes ( p = 0.001) were significantly associated with long-term complications. At the last follow-up (median duration of 43 months), 15.9% of patients had unresolved complications. LIMITATIONS: The retrospective design. CONCLUSIONS: Patients undergoing lateral pelvic node dissection experienced a higher frequency of long-term complications, but half of them had asymptomatic lymphoceles, most of which resolved spontaneously. However, further efforts should be paid to reduce anticipated complications related to lateral pelvic node dissection. See Video Abstract . COMPLICACIONES A LARGO PLAZO DE LA DISECCIN DE LOS GANGLIOS LIFTICOS PLVICOS LATERALES LAPAROSCPICA O ROBTICA DESPUS DE LA QUIMIORRADIOTERAPIA PREOPERATORIA CONTRA EL CNCER DEL RECTO LOCALMENTE AVANZADO: ANTECEDENTES:Los pacientes con cáncer del recto sometidos a disección ganglionar linfática pélvica lateral podrían tener mayor riesgo de complicaciones postoperatorias derivadas de la complejidad técnica. Sin embargo, se sabe poco sobre las complicaciones a largo plazo después de la disección de los ganglios linfáticos pélvicos laterales.OBJETIVOS:Investigar las complicaciones a largo plazo de la quimiorradioterapia preoperatoria, seguida de escisión mesorrectal total con disección de los ganglios linfáticos pélvicos laterales contra el cáncer de recto localmente avanzado.DISEÑO:Un análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTES:Este estudio se llevó a cabo en un centro oncológico terciario.PACIENTES:Se analizaron pacientes con cáncer de recto que se sometieron a escisión mesorrectal total con disección de ganglios linfáticos pélvicos laterales después de quimiorradioterapia preoperatoria entre 2011 y 2019. Todas las operaciones se realizaron mediante abordaje laparoscópico o robótico.PRINCIPALES MEDIDAS DE RESULTADO:Las complicaciones a largo plazo se definieron como eventos adversos que persistieron o aparecieron recientemente ≥ 90 días después de la cirugía y podrían estar relacionados con la cirugía.RESULTADOS:Un total de 164 pacientes se sometieron a escisión mesorrectal total con disección de los ganglios linfáticos pélvicos laterales después de quimiorradioterapia preoperatoria. Las tasas de complicaciones a corto y largo plazo fueron del 36,0% y 36,6%, respectivamente. El linfocele fue la complicación a largo plazo más común (17,7% de los pacientes) y el 11,6% tuvo fuga anastomótica con seno crónico. De los pacientes con complicaciones a largo plazo, el 20,7% de los pacientes necesitaron reingreso para recibir tratamiento. De 29 pacientes con linfocele, 13 (41,0%) experimentaron absorción espontánea y 11 (37,9%) requirieron drenaje quirúrgico o percutáneo con catéter o uso de antibióticos. El análisis multivariado mostró metástasis patológicas en los ganglios linfáticos pélvicos ( p = 0,008) y un mayor número de ganglios pélvicos extraídos unilateralmente ( p = 0,001) se asociaron significativamente con complicaciones a largo plazo. En el último seguimiento (mediana de 43 meses), el 15,9% de los pacientes tuvieron complicaciones no resueltas.LIMITACIÓN:El diseño retrospectivo.CONCLUSIONES:Los pacientes sometidos a disección de ganglios pélvicos linfáticos laterales experimentaron una mayor frecuencia de complicaciones a largo plazo, pero la mitad de ellos tuvieron linfoceles asintomáticos, la mayoría de los cuales se resolvieron espontáneamente. Sin embargo, se deben realizar mayores esfuerzos para reducir las complicaciones previstas relacionadas con la disección de los ganglios linfáticos pélvicos laterales. (Traducción-Dr. Aurian Garcia Gonzalez ).

Comparison of the efficacy and safety of single-port versus multi-port robotic total mesorectal excision for rectal cancer: A propensity score-matched analysis.

BACKGROUND: It is unknown whether the da Vinci single-port system performs similarly to the previous multi-port system during complicated procedures, such as rectal cancer surgery. Therefore, we compared the short-term clinical outcomes of single-port and multi-port robotic total mesorectal excision for the treatment of rectal cancer. METHODS: This retrospective study reviewed 128 patients who underwent robotic total mesorectal excision between July 2020 and June 2022, of whom 84 (42 each: single-port versus multi-port) were included in the propensity score-matched cohort. Perioperative and pathologic outcomes were compared between groups. RESULTS: Median tumor height was similar between groups (single-port versus multi-port, 5.9 ± 2.1 vs 5.6 ± 1.8 cm, P = .719). Preoperative chemoradiotherapy was performed equally. The total operative time was less (160.0 ± 42.2 minutes vs 199.6 ± 78.6 minutes, P = .005), the total length of incision was shorter (4.0 ±0.3 vs 5.4 ± 0.7 cm, P = .003), postoperative hospital stay was shorter (6.2 ±1.7 vs 7.2 ±2.8 days, P = .050), and C-reactive protein levels on postoperative day 3 trended to be lower (7.3 ± 4.7 vs 8.9 ± 5.6 mg/L, P = .096) in the single-port group, compared with the multi-port group. Postoperative complications did not differ between groups (single-port versus multi-port, 11.9% vs 16.6%, P = .864). Anastomotic leakage occurred in 1 and 2 patients in the single-port and multi-port groups, respectively. The circumferential resection margins were positive in 1 patient in the multi-port group. CONCLUSION: The perioperative outcomes of single-port robotic total mesorectal excision were comparable to those of multi-port robotic TME. The single-port robot can be considered a surgical option for treating rectal cancer.

Single-port versus multiport robotic total mesorectal excision for rectal cancer: initial experiences by case-matched analysis of short-term outcomes.

Purpose: The da Vinci single-port (SP) system has been used in various surgical fields, including colorectal surgery. However, limited experience has been reported on its safety and feasibility. This study aims to evaluate the short-term outcomes of SP robotic surgery for the treatment of rectal cancer compared with multiport (MP) robotic surgery. Methods: Rectal cancer patients who underwent curative resection in 2020 were reviewed. A total of 43 patients underwent robotic total mesorectal excision (TME), of which 26 (13 in each group, SPTME vs. MPTME) were included in the case-matched cohort for analysis. Intraoperative and postoperative outcomes and pathological results were compared between the 2 groups. Results: Median tumor height was similar between the 2 groups (SPTME vs. MPTME: 5.9 cm [range, 2.2-9.6 cm] vs. 6.7 cm [range, 3.4-10.0 cm], P = 0.578). Preoperative chemoradiotherapy was equally performed (38.5%). The median estimated blood loss was less (20.0 mL [range, 5.0-20.0 mL] vs. 30.0 mL [range, 20.0-30.0 mL], P = 0.020) and the median hospital stay was shorter (7 days [range, 6-8 days] vs. 8 days [range, 7-9 days], P = 0.055) in the SPTME group. Postoperative complications did not differ (SPTME vs. MPTME: 7.7% vs. 23.1%, P = 0.587). One patient in the SPTME group and 3 in the MPTME group experienced anastomotic leakage. Conclusion: SP robotic TME showed perioperative outcomes similar to MP robotic TME. The SP robotic system can be considered a surgical option for the treatment of rectal cancer. Further prospective randomized trials with larger cohorts are required.

Comparison of the effects of dexmedetomidine and propofol on the cardiovascular autonomic nervous system during spinal anesthesia: preliminary randomized controlled observational study.

Spinal anesthesia induces sympatholysis and is usually combined with dexmedetomidine or propofol which induce different hemodynamic changes. The purpose of this study was to compare the effect on autonomic nervous system between dexmedetomidine and propofol combined with spinal anesthesia. Patients aged 20-65 undergoing elective surgery under spinal anesthesia were randomly assigned to dexmedetomidine or propofol group. Heart rate variability (HRV) and hemodynamic variables were measured at four time points: T0, baseline; T1, 10 min after spinal anesthesia; T2, 10 min after sedative administration; and T3, 20 min after sedative administration. In 59 patients, dexmedetomidine and propofol groups had significantly different hemodynamic changes over time (time × group effect P < 0.001). The dexmedetomidine group had slower heart rate at T2 (P = 0.001) and higher blood pressures at T2 and T3 (P < 0.001) than the propofol group. Overall HRV dynamics showed a significant change over time from T0 to T3, but both groups exhibited similar trends. Compared to the baseline data within the group, the low frequency (LF) decreased in both groups but the decrease occurred at T2 in the propofol group and at T3 in the dexmedetomidine group. The high frequency (HF) increased at T2 and T3 only in the dexmedetomidine group. The LF/HF ratio decreased in the dexmedetomidine group at T3. Dexmedetomidine showed slower heart rate and higher blood pressure than propofol when combined with spinal anesthesia, however, dexmedetomidine and propofol exhibited similar trends in HRV dynamics. Compared with the baseline within each group, both agents decreased LF, but only dexmedetomidine increased HF and decreased in the LF/HF ratio significantly.

Chiroptical Synaptic Heterojunction Phototransistors Based on Self-Assembled Nanohelix of π-Conjugated Molecules for Direct Noise-Reduced Detection of Circularly Polarized Light.

High-performance chiroptical synaptic phototransistors are successfully demonstrated using heterojunctions composed of a self-assembled nanohelix of a π-conjugated molecule and a metal oxide semiconductor. To impart strong chiroptical activity to the device, a diketopyrrolopyrrole-based π-conjugated molecule decorated with chiral glutamic acid is newly synthesized; this molecule is capable of supramolecular self-assembly through noncovalent intermolecular interactions. In particular, nanohelix formed by intertwinded fibers with strong and stable chiroptical activity in a solid-film state are obtained through hydrogen-bonding-driven, gelation-assisted self-assembly. Phototransistors based on interfacial charge transfer at the heterojunction from the chiroptical nanohelix to the metal oxide semiconductor show excellent chiroptical detection with a high photocurrent dissymmetry factor of 1.97 and a high photoresponsivity of 218 A W-1 . The chiroptical phototransistor demonstrates photonic synapse-like, time-dependent photocurrent generation, along with persistent photoconductivity, which is attributed to the interfacial charge trapping. Through the advantage of synaptic functionality, a trained convolutional neural network successfully recognizes noise-reduced circularly polarized images of handwritten alphabetic characters with better than 89.7% accuracy.

Short-term outcomes of Early versus conventional adjuvant chemotherapy in stage III colon cancer: randomized clinical trial.

BACKGROUND: Evidence is lacking regarding the earliest timing of initiating adjuvant chemotherapy to maximize its efficacy safely. A trial was designed and conducted to evaluate the safety and oncological efficacy of early adjuvant chemotherapy compared with conventional adjuvant chemotherapy. The short-term outcomes are reported here. METHODS: A multicentre, randomized (1 : 1), open-label, phase III trial was conducted comparing early adjuvant chemotherapy with conventional adjuvant chemotherapy in patients with stage III colon cancer. Patients who underwent radical surgery who had stage III colon cancer confirmed by histopathological assessment were screened and randomized into the early adjuvant chemotherapy arm or the conventional adjuvant chemotherapy arm. The primary endpoint was 3-year disease-free survival. The adjuvant chemotherapy with FOLFOX was delivered between postoperative day 10 and 14 in the early adjuvant chemotherapy arm, and between postoperative day 24 and 28 in the conventional adjuvant chemotherapy arm. Toxicity and quality of life were evaluated. RESULTS: Between 9 September 2011 and 6 March 2020, 443 patients consented to randomization at eight sites. The intention-to-treat population included 423 patients (209 in the early adjuvant chemotherapy arm and 214 in the conventional adjuvant chemotherapy arm), and the safety population included 380 patients (192 in the early adjuvant chemotherapy arm and 188 in the conventional adjuvant chemotherapy arm). There was no statistically significant difference in overall toxicity (28.1 per cent in the early adjuvant chemotherapy arm and 28.2 per cent in the conventional adjuvant chemotherapy arm, P = 0.244), surgical complications, and quality of life between the two arms. CONCLUSION: Adjuvant chemotherapy can be safely initiated 2 weeks after surgery with toxicity and quality of life comparable to conventional adjuvant chemotherapy for stage III colon cancer.

Single-Port Robotic Intersphincteric Resection for the Treatment of Rectal Cancer.

BACKGROUND: The da Vinci Single-port (SP) system is designed to facilitate single-incision robotic surgery in a narrow space. We developed a new procedure of intersphincteric resection (ISR) using the SP platform and evaluated the technical safety and feasibility of this procedure for the treatment of very low rectal cancer. MATERIALS AND METHODS: Eleven rectal cancer patients who underwent SP robotic ISR between August 2020 and July 2021 were included. Patients' clinical characteristics, operative and pathologic findings of the patients were retrospectively analyzed. RESULTS: The median tumor height was 3 cm (range, 2-4 cm). A single docking was performed, and the median docking time was 3 min 10 sec (range, 2 min 50 sec-3 min 30 sec). The median total operation time was 210 min (range, 150-280 min), and the median time of pelvic dissection was 57 min (range, 45-68 min). All patients presented with negative distal resection margins [median 1 cm (range, 0.5-2.0 cm)], and only one patient had less than 1mm of circumferential resection margin (0.9 mm). CONCLUSIONS: Our initial experience suggests that SP robotic ISR is safe and feasible.

Robotic and laparoscopic salvage lateral pelvic node dissection for the treatment of recurrent rectal cancer.

BACKGROUND: The lateral pelvic sidewall is a major site of local recurrence after radical resection of rectal cancer. Salvage lateral pelvic node dissection (LPND) may be the only way to eliminate recurrent lateral pelvic nodes (LPNs). This study aimed to describe the technical details of robotic and laparoscopic salvage LPND and assess the short-term clinical and oncological outcomes in patients with recurrent LPNs who underwent salvage LPND by a minimally invasive approach for curative intent. METHODS: Between September 2010 and 2019, 36 patients who underwent salvage surgery for LPN recurrence were retrospectively analyzed from a prospectively maintained database. Patients' characteristics, index operation, MRI findings, and perioperative and pathological outcomes were analyzed. RESULTS: Eleven and 14 patients underwent robotic and laparoscopic salvage LPND, respectively. Eight patients (32.0%) underwent a combined salvage operation for resectable extra-pelvic sidewall metastases. There were four cases of open-conversion during the laparoscopic approach due to uncontrolled bleeding of iliac vessels. In these patients, metastatic LPNs were suspected of iliac vessel invasion and were found to be larger in size (median 15 mm; range 12-20) than that in patients who underwent successful LPND using the minimally invasive approach (median 10 mm; range 5-20). The median number of metastatic LPNs and harvested LPNs was 1 (range 0-3) and 6 (range 1-16), respectively. Six patients (24.0%) experienced postoperative complications including lymphoceles and voiding difficulties. During the follow-up (median 44.6 months; range 24.0-87.7), eight patients developed recurrences, mainly the lung and para-aortic lymph nodes, and one patient developed pelvic sidewall recurrence after laparoscopic salvage LPND. The 3-year disease-free survival and overall survival after salvage LPND were 66.4% and 79.2%, respectively. CONCLUSIONS: Robotic and laparoscopic salvage LPND for recurrent LPNs are safe and feasible with favorable short-term surgical outcomes. However, the surgical approach should be carefully chosen in patients with large-sized and invasive recurrent LPNs.

Efficacy of air leak test in detection of anastomotic leaks after rectal excision: a retrospective case-controlled study.

Purpose: Although its efficacy is uncertain, an intraoperative air leak test (ALT) is commonly used to detect mechanical defects following bowel anastomosis. This study aimed to evaluate the efficacy of ALT to detect anastomotic leakage (AL) following rectal excision. Methods: We reviewed our database for patients with rectal cancers who had undergone curative surgery between January 2012 and January 2018. Patients were grouped according to whether or not an ALT was performed. Propensity score analyses were performed to compare outcomes for groups in a 1:1 case-matched cohort. Results: In total, 1,191 patients underwent rectal excision; 438 (219 in each group) formed the case-matched cohort for analysis. The protective stoma rate was 16.0% and 14.6% in the ALT and the no-ALT groups, respectively (P = 0.791). In the ALT group, 2 patients (0.9%) showed a positive result and were treated with rectal tube drainage, resulting in no leakage. There was no significant difference in postoperative AL rate between the groups (ALT group: 4.6% vs. no-ALT group: 4.1%, P > 0.999). Conclusion: ALT played a minimal role in detecting AL following rectal excision. Further studies are warranted to validate our results and clarify whether AL can be prevented with ALT or alternative methods.

Comparison of Laparoscopic Versus Robot-Assisted Surgery for Rectal Cancers: The COLRAR Randomized Controlled Trial.

OBJECTIVE: To evaluate whether robotic for middle or low rectal cancer produces an improvement in surgical outcomes compared with laparoscopic surgery in a randomized controlled trial (RCT). BACKGROUND: There is a lack of proven clinical benefit of robotic total mesorectal excision (TME) compared with a laparoscopic approach in the setting of multicenter RCTs. METHODS: Between July 2011 and February 2016, patients diagnosed with an adenocarcinoma located <10 cm from the anal verge and clinically rated T1-4aNxM0 were enrolled. The primary outcome was the completeness of TME assessed by a surgeon and a pathologist. RESULTS: The RCT was terminated prematurely because of poor accrual of data. In all, 295 patients were assigned randomly to a robot-assisted TME group (151 in R-TME) or a laparoscopy-assisted TME group (144 in L-TME). The rates of complete TME were not different between groups (80.7% in R-TME, 77.1% in L-TME). Pathologic outcomes including the circumferential resection margin and the numbers of retrieved lymph nodes were not different between groups. In a subanalysis, the positive circumferential resection margin rate was lower in the R-TME group (0% vs 6.1% for L-TME; P =0.031). Among the recovery parameters, the length of opioid use was shorter in the R-TME group ( P =0.028). There was no difference in the postoperative complication rate between the groups (12.0% for R-TME vs 8.3% for L-TME). CONCLUSIONS: In patients with middle or low rectal cancer, robotic-assisted surgery did not significantly improve the TME quality compared with conventional laparoscopic surgery (ClinicalTrial.gov ID: NCT01042743).

Fermi-Level Pinning-Free WSe2 Transistors via 2D Van der Waals Metal Contacts and Their Circuits.

Precise control over the polarity of transistors is a key necessity for the construction of complementary metal-oxide-semiconductor circuits. However, the polarity control of 2D transistors remains a challenge because of the lack of a high-work-function electrode that completely eliminates Fermi-level pinning at metal-semiconductor interfaces. Here, a creation of clean van der Waals contacts is demonstrated, wherein a metallic 2D material, chlorine-doped SnSe2 (Cl-SnSe2 ), is used as the high-work-function contact, providing an interface that is free of defects and Fermi-level pinning. Such clean contacts made from Cl-SnSe2 can pose nearly ideal Schottky barrier heights, following the Schottky-Mott limit and thus permitting polarity-controllable transistors. With the integration of Cl-SnSe2 as contacts, WSe2 transistors exhibit pronounced p-type characteristics, which are distinctly different from those of the devices with evaporated metal contacts, where n-type transport is observed. Finally, this ability to control the polarity enables the fabrication of functional logic gates and circuits, including inverter, NAND, and NOR.

Oncologic benefit of adjuvant chemotherapy for locally advanced rectal cancer after neoadjuvant chemoradiotherapy and curative surgery with selective lateral pelvic lymph node dissection: An international retrospective cohort study.

INTRODUCTION: Intensive local treatment comprising total mesorectal excision (TME) with selective lateral pelvic lymph node dissection (LPND) after neoadjuvant chemoradiotherapy (CRT) for locally advanced rectal cancer (LARC) has received attention among clinicians treating rectal cancer. It remains unclear whether adjuvant chemotherapy (ACT) after intensive local treatment is beneficial for these patients. We evaluated the oncologic benefit of ACT for patients with LARC who received intensive local treatment. MATERIALS AND METHODS: This international multicentre retrospective cohort study included 737 patients treated in Japan and Korea between 2010 and 2017. The effectiveness of ACT on recurrence-free survival (RFS) was evaluated using univariable and multivariable Cox proportional hazards models, with subgroup analyses to identify subpopulations potentially benefiting from ACT. RESULTS: The median follow-up was 49 months; the 5-year RFS and local recurrence rates for the entire cohort were 72.1% and 4.9%, respectively; 514 patients (69.7%) received adjuvant chemotherapy, without an oncologic benefit (hazard ratio, 1.14; 95% confidence interval [CI]: 0.79-1.68) demonstrated in the multivariable Cox regression analysis. In subgroup analyses, the distributions of the 95% CI in patients aged ≥70 years and those with ypStage 0 tended to place a disproportionate emphasis that favoured the non-ACT treatment strategy. CONCLUSION: Despite achieving good local control with intensive local treatment strategy, the effectiveness of ACT for the LARC patients with CRT followed by TME with selective LPND was not proved. Elderly patients and those with ypStage0 may not receive benefit from ACT after CRT and TME ± LPND.

Stepwise Improvement of Surgical Quality in Robotic Lateral Pelvic Node Dissection: Lessons From 100 Consecutive Patients With Locally Advanced Rectal Cancer.

BACKGROUND: Lateral pelvic node dissection has significant technical difficulty and a high incidence of surgical morbidity. A steep learning curve is anticipated in performing lateral pelvic node dissection. However, no study has previously analyzed the learning curve and surgical skill acquisition for this complex procedure. OBJECTIVES: We aimed to evaluate the learning process for performing robotic total mesorectal excision with lateral pelvic node dissection in patients with rectal cancer. DESIGN: This is a retrospective analysis of a prospectively collected database. SETTING: This study was conducted at a tertiary cancer center. PATIENTS: A total of 100 patients who underwent robotic total mesorectal excision with lateral pelvic node dissection between 2011 and 2017 were included. MAIN OUTCOME MEASURES: A cumulative sum analysis was calculated based on the number of unilateral retrieved lateral pelvic nodes. Operative time, estimated bloodloss, lateral pelvic node metastatic rate, postoperative morbidities, and local recurrence were also analyzed. RESULTS: Cumulative sum modeling suggested 4 learning phases: learning I (33 patients), learning II (19 patients), consolidation (30 patients), and competence (18 patients). In the consolidation and competence phases, we adopted fluorescence imaging and standardized the surgical procedure on the basis of anatomical planes. The competence phase had the greatest number of unilateral retrieved lateral pelvic nodes (12.8 vs 4.9, 8.2, and 10.4; p < 0.001). Urinary complications, including urinary retention and postoperative α-blocker usage, were more frequently observed in learning phase I than in the competence phase (39.4% vs 16.7%, p = 0.034). During the median follow-up of 44.2 months, local recurrence in the pelvic sidewall was observed in 4 patients from learning phase I and in 1 patient from learning phase II. LIMITATIONS: This study was limited by its retrospective design. CONCLUSION: Completeness of the lateral pelvic node dissection procedure increased with the surgeon's experience and as new imaging systems and surgical technique standardization were implemented. Further studies are warranted to determine the oncologic outcomes associated with each phase. See Video Abstract at http://links.lww.com/DCR/B774. MEJORA GRADUAL DE LA CALIDAD QUIRRGICA EN LA DISECCIN LINFTICA PLVICA LATERAL ROBTICA LECCIONES DE PACIENTES CONSECUTIVOS CON CNCER DE RECTO LOCALMENTE AVANZADO: ANTECEDENTES:La disección linfática pélvica lateral tiene una dificultad técnica significativa y una alta incidencia de morbilidad quirúrgica. Se prevé una curva de aprendizaje muy pronunciada al realizar la disección linfática pélvica lateral. Sin embargo, ningún estudio ha analizado previamente la curva de aprendizaje y la adquisición de habilidades quirúrgicas para este procedimiento.OBJETIVOS:Nuestro objetivo fue evaluar el proceso de aprendizaje para realizar la escisión total de mesorrecto robótica con disección linfática pélvica lateral en pacientes con cáncer de recto.DISEÑO:Este es un análisis retrospectivo de una base de datos recopilada prospectivamente.AJUSTE:Este estudio se realizó en un centro oncológico terciario.PACIENTES:Un total de 100 pacientes fueron sometidos a escisión total de mesorrecto robótica con disección linfática pélvica lateral entre 2011 y 2017.PRINCIPALES MEDIDAS DE DESENLACE:Se calculó un análisis de suma acumulativa basado en el número unilateral de ganglios pélvicos laterales recuperados. También se analizaron el tiempo operatorio, la pérdida de sangre estimada, la tasa de metástasis ganglionares pélvicas laterales, las morbilidades postoperatorias y la recidiva local.RESULTADOS:El modelado total acumulativo sugirió cuatro fases de aprendizaje: aprendizaje I (33 pacientes), aprendizaje II (19 pacientes), consolidación (30 pacientes) y competencia (18 pacientes). En las fases de consolidación y competencia, adoptamos imágenes de fluorescencia y estandarizamos el procedimiento quirúrgico basado en planos anatómicos, respectivamente. La fase de competencia tuvo el mayor número de ganglios pélvicos laterales recuperados unilateralmente (12,8 frente a 4,9, 8,2 y 10,4; p < 0,001). Las complicaciones urinarias, incluida la retención urinaria y el uso posoperatorio de bloqueadores beta, se observaron con más frecuencia en la fase de aprendizaje I que en la fase de competencia (39,4% frente a 16,7%, p = 0,034). Durante la mediana de seguimiento de 44,2 meses, se observó una recidiva local en la pared lateral pélvica en cuatro pacientes de la fase de aprendizaje I y en un paciente de la fase de aprendizaje II.LIMITACIONES:Este estudio estuvo limitado por su diseño retrospectivo.CONCLUSIÓNES:La completitud del procedimiento de disección linfática pélvica lateral aumentó con la experiencia del cirujano y a medida que se implementaron nuevos sistemas de imágenes y estandarización de técnicas quirúrgicas. Se necesitan más estudios para determinar los resultados oncológicos asociados con cada fase. Consulte Video Resumen en http://links.lww.com/DCR/B774.

An Asymmetry Field-Effect Phototransistor for Solving Large Exciton Binding Energy of 2D TMDCs.

The probing of fundamental photophysics is a key prerequisite for the construction of diverse optoelectronic devices and circuits. To date, though, photocarrier dynamics in 2D materials remains unclear, plagued primarily by two issues: a large exciton binding energy, and the lack of a suitable system that enables the manipulation of excitons. Here, a WSe2 -based phototransistor with an asymmetric split-gate configuration is demonstrated, which is named the "asymmetry field-effect phototransistor" (AFEPT). This structure allows for the effective modulation of the electric-field profile across the channel, thereby providing a standard device platform for exploring the photocarrier dynamics of the intrinsic WSe2 layer. By controlling the electric field, this work the spatial evolution of the photocurrent is observed, notably with a strong signal over the entire WSe2 channel. Using photocurrent and optical spectroscopy measurements, the physical origin of the novel photocurrent behavior is clarified and a room-temperature exciton binding energy of 210 meV is determined with the device. In the phototransistor geometry, lateral p-n junctions serve as a simultaneous pathway for both photogenerated electrons and holes, reducing their recombination rate and thus enhancing photodetection. The study establishes a new device platform for both fundamental studies and technological applications.

Impact of the distal resection margin on local recurrence after neoadjuvant chemoradiation and rectal excision for locally advanced rectal cancer.

We aimed to evaluate whether a short distal resection margin (< 1 cm) was associated with local recurrence in patients with locally advanced rectal cancer who underwent preoperative chemoradiotherapy. Patients with rectal cancer who underwent preoperative chemoradiotherapy followed by curative surgery were divided into two groups based on the distal resection margin (≥ 1 cm and < 1 cm). In total, 507 patients were analyzed. The median follow-up duration was 48.9 months. The 3-year local recurrence rates were 2% and 8% in the ≥ 1 cm and < 1 cm groups, respectively (P < 0.001). Multivariable analysis revealed that a distal resection margin of < 1 cm was a significant risk factor for local recurrence (P = 0.008). Subgroup analysis revealed that a distal resection margin of < 1 cm was not an independent risk factor for local recurrence in the ypT0-1 group. However, among patients with tumor stages ypT2-4, the cumulative 3-year incidences of local recurrence were 2.3% and 9.8% in the ≥ 1 cm and < 1 cm groups, respectively (P = 0.01). A distal resection margin of < 1 cm might influence local recurrence rates in patients with locally advanced rectal cancer undergoing preoperative chemoradiotherapy, especially in patients with tumor stages ypT2-4.

Clinical Impact of Postoperative Vitamin D Deficiency on the Recurrence of Colon Cancer After Curative Surgical Resection.

BACKGROUND/AIM: There are no clinically significant cutoff values of serum vitamin D levels and time points to predict the prognosis of colon cancer, particularly in patients who underwent curative surgical resection. PATIENTS AND METHODS: We retrospectively analyzed serum vitamin D levels in 795 patients with stages I to III colon cancer who underwent curative surgical resection. RESULTS: Patients with vitamin D levels below 12 ng/ml at one year after surgical resection demonstrated a significantly reduced disease-free survival (DFS) than those who did not have vitamin D deficiency (p=0.01). In the multivariate analysis, an age of 70 years or older [hazard ratio (HR)=1.992; p=0.001], pathologic stage (HR=3.739; p<0.001), and vitamin D deficiency (less than 12 ng/ml) at one year after surgery (HR=0.563; p=0.020) were factors unfavorably influencing DFS. CONCLUSION: In patients with stages I to III of colon cancer, vitamin D deficiency at one year after surgical resection was associated with increased disease relapse.

Initial experience of preoperative short-course radiotherapy followed by oxaliplatin-based consolidation chemotherapy for locally advanced rectal cancer.

PURPOSE: We analyzed the safety and feasibility of preoperative short-course radiotherapy (SCRT) followed by consolidation chemotherapy for patients with locally advanced rectal cancer (LARC). METHODS: From April 2018 to May 2019, 19 patients with LARC were treated with SCRT followed by three cycles of consolidation chemotherapy with leucovorin, fluorouracil, and oxaliplatin (FOLFOX6) before surgery. Adjuvant chemotherapy relied on oxaliplatin. Tumor response, patient compliance, and toxicities were analyzed. RESULTS: The median age was 60 years (range 44-71), and 16 of the patients were male. The median tumor height was 5 cm (range 0-9) from anal verge. All patients received a total dose of 25 Gy in five fractions. The number of cycles of FOLFOX6 before surgery was three in 17, four in one, five in one. Five patients required dose reductions in consolidation chemotherapy. The median interval between initiation of SCRT and surgery was 10.6 weeks (range 8.6-16.4). A pathologic complete response was seen in two patients (11%). Grade III toxicities to the preoperative treatment were seen in five patients (26%): diarrhea in two, a decreased white blood cell count in one, and anemia in two. Postoperative complications arising within 30 days developed in five patients (26%). During the median follow-up period of 20.4 months, there was no tumor recurrence. CONCLUSION: Preoperative SCRT followed by oxaliplatin-based consolidation chemotherapy showed acceptable toxicity and feasibility in patients with LARC. Prospective randomized trials are warranted to verify the efficacy and safety of this treatment strategy compared with conventional long-course concurrent chemoradiotherapy.

Prospective study of oncologic outcomes after laparoscopic modified complete mesocolic excision for non-metastatic right colon cancer (PIONEER study): study protocol of a multicentre single-arm trial.

BACKGROUND: The introduction of complete mesocolic excision (CME) with central vascular ligation (CVL) for right-sided colon cancer has improved the oncologic outcomes. Recently, we have introduced a modified CME (mCME) procedure that keeps the same principles as the originally described CME but with a more tailored approach. Some retrospective studies have reported the favourable oncologic outcomes of laparoscopic mCME for right-sided colon cancer; however, no prospective multicentre study has yet been conducted. METHODS: This study is a multi-institutional, prospective, single-arm study evaluating the oncologic outcomes of laparoscopic mCME for adenocarcinoma arising from the right side of the colon. A total of 250 patients will be recruited from five tertiary referral centres in South Korea. The primary outcome of this study is 3-year disease-free survival. Secondary outcome measures include 3-year overall survival, incidence of surgical complications, completeness of mCME, and distribution of metastatic lymph nodes. The quality of laparoscopic mCME will be assessed on the basis of photographs of the surgical specimen and the operation field after the completion of lymph node dissection. DISCUSSION: This is a prospective multicentre study to evaluate the oncologic outcomes of laparoscopic mCME for right-sided colon cancer. To the best of our knowledge, this will be the first study to prospectively and objectively assess the quality of laparoscopic mCME. The results will provide more evidence about oncologic outcomes with respect to the quality of laparoscopic mCME in right-sided colon cancer. TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT03992599 (June 20, 2019). The posted information will be updated as needed to reflect protocol amendments and study progress.