Novel endoscopic therapeutics for early gastric cancer

Comparison of complications between laparoscopic and open gastrectomies for early gastric cancer by a nationwide propensity score-matched cohort study

The safety of laparoscopic gastrectomy compared with that of open surgery for the treatment of early gastric cancer (EGC) is unidentified on a national scale. We aimed to compare the morbidity between laparoscopic and open gastrectomies for pathological T1 gastric cancer based on nationwide survey data. Data of 14,076 patients who underwent gastric cancer surgery obtained from the 2019 Korean Gastric Cancer Association-led nationwide survey were used. For patients with pathological T1 gastric cancer, the clinical characteristics were compared between the laparoscopic and open gastrectomy groups. Propensity score matching (PSM) was performed to match the baseline characteristics of the groups. Among the 7765 patients with pathological T1 gastric cancer who underwent open or laparoscopic gastrectomy, 612 pairs were matched. After balancing the baseline characteristics, the laparoscopic gastrectomy group had a significantly longer operative time, less blood loss, greater number of harvested lymph nodes, shorter hospital stays, and comparable morbidity, compared with the open gastrectomy group (P < 0.001, P < 0.001, P < 0.001, P = 0.001, and P = 0.709, respectively). The surgical approach was not a risk factor for postoperative complication in logistic regression analysis. The PSM analysis with the 2019 Korean nationwide survey data demonstrated that laparoscopic gastrectomy showed comparable morbidity with open gastrectomy for EGC.

A Symmetric-Actuating Linear Piezoceramic Ultrasonic Motor Capable of Producing a Scissoring Effect

Conventionally, to produce a linear motion, one motor's stator is employed to drive one runner moving forward or backward. So far, there is almost no report of one electromechanical motor or piezoelectric ultrasonic motor that can directly generate two symmetrical linear motions, while this function is desired for precise scissoring and grasping in the minimally invasive surgery field. Herein, we report a brand-new symmetric-actuating linear piezoceramic ultrasonic motor capable of generating symmetrical linear motions of two outputs directly without additional mechanical transmission mechanisms. The key component of the motor is an (2 × 3) arrayed piezoceramic bar stator operating in the coupled resonant mode of the first longitudinal (L₁) and third bending (B₃) modes, leading to symmetric elliptical vibration trajectories at its two ends. A pair of microsurgical scissors is used as the end-effector, demonstrating a very promising future for high-precision microsurgical operations. The sliders of the prototype show the following features: (a) symmetrical, fast relative moving velocity (~1 m/s) outward or inward simultaneously; (b) high step resolution (40 nm); and (c) high power density (405.4 mW/cm³) and high efficiency (22.1%) that are double those of typical piezoceramic ultrasonic motors, indicating the full capacity of symmetric-actuating linear piezoceramic ultrasonic motor working in symmetric operation principle. This work also has enlightening significance for future symmetric-actuating device designs.

Robotics in therapeutic endoscopy (with video)

Since its inception, endoscopy has evolved from a solely diagnostic procedure to an expanding therapeutic field within gastroenterology. The incorporation of robotics in gastroenterology initially addressed shortcomings of flexible endoscopes in natural orifice transluminal endoscopy. Developing therapeutic endoscopic robotic platforms now offer operators improved ergonomics, visualization, dexterity, precision, and control and the possibility of increasing proficiency and standardization of complex endoscopic procedures including endoscopic submucosal dissection, endoscopic full-thickness resection, and endoscopic suturing. The following review discusses the history, potential applications, and tools currently available and in development for robotics in therapeutic endoscopy.

Gastric Cancer: Emerging Trends in Prevention, Diagnosis, and Treatment

Gastric adenocarcinoma (GC) is the fourth leading cause of global cancer mortality, and the leading infection-associated cancer. Helicobacter pylori is the dominant risk factor for GC and classified as an IARC class I carcinogen. Surveillance of gastric premalignant conditions is now indicated in high-risk patients. Upper endoscopy is the gold standard for GC diagnosis, and image-enhanced endoscopy increases the detection of gastric premalignant conditions and early gastric cancer (EGC). Clinical staging is crucial for treatment approach, defining early gastric cancer, operable locoregional disease, and advanced GC. Endoscopic submucosal dissection is the treatment of choice for most EGC. Targeted therapies are rapidly evolving, based on biomarkers including MSI/dMMR, HER2, and PD-L1. These advancements in surveillance, diagnostic and therapeutic strategies are expected to improve GC survival rates in the near term.

Advances in screening and detection of gastric cancer

With an estimated one million new cases and 769 000 deaths in 2020, gastric cancer is the fifth most frequent cancer and fourth leading cause of cancer death globally. Incidence rates are highest in Asia and Eastern Europe. This manuscript will review the current modalities of diagnosis, staging, and screening of gastric cancer. We will also highlight development of novel diagnostics and advancements in endoscopic detection of early gastric cancer.

Endoscopic submucosal dissection using a detachable assistant robot: a comparative in vivo feasibility study (with video)

BACKGROUND

Appropriate tissue tension and clear visibility of the dissection area using traction are essential for effective and safe endoscopic submucosal dissection (ESD). We developed a robotic assistive traction device for flexible endoscopy and compared its safety and efficiency in ESD between experienced and novice endoscopists.

METHODS

Robotic ESD was performed by experienced and novice endoscopist groups (n = 2, each). The outcomes included time to complete each ESD step, total procedure time, size of the dissected mucosa, rate of en bloc resection, and major adverse events. Furthermore, incision and dissection speeds were compared between groups.

RESULTS

Sixteen gastric lesions were resected from nine live pigs. The submucosal incision speed was significantly faster in the expert group than in the novice group (P = 0.002). There was no significant difference in the submucosal dissection speed between the groups (P = 0.365). No complications were reported in either group.

CONCLUSIONS

When the robot was assisting in the ESD procedure, the dissection speed improved significantly, especially in the novice surgeons. Our robotic device can provide simple, effective, and safe multidirectional traction during ESD.

Increased survival rates in gastric cancer, with a narrowing gender gap and widening socioeconomic status gap: A period analysis from 1984 to 2013

BACKGROUND AND AIM

Gastric cancer (GC) has the fifth highest incidence rate of all cancers and has a poor prognosis. However, no recent large-scale and long-term studies have evaluated the incidence and survival rates of individuals with GC.

METHODS

In order to explore the change of GC incidence and survival rates by age, gender, race, and socioeconomic status (SES), incidence data and survival status of patients with GC between 1984 and 2013 were abstracted from the Surveillance, Epidemiology, and End Results database. Totally, 87 242 cases of GC were exported and were analyzed.

RESULTS

During these three decades, the incidence of GC was 7.4, 6.8, and 5.5 per 100 000 individuals in each decade. The 1-year relative survival rates (RSRs) improved from 42.4% to 44.3% to 49.0% (P < 0.0001), with a larger increase seen in the third decade. However, the long-term survival rates remained low (from 17.8% to 20.3% to 22.9% for the 5-year RSRs, P < 0.0001; from 14.1% to 16.4% to 18.6% for the 10-year RSRs, P < 0.0001).

CONCLUSION

Our analysis demonstrated the decreased incidence and increased survival rate of GC. In addition, lower SES was associated with lower survival rates. It is notable that others (primarily for Asians) had the highest incidence rate but had better outcomes than Whites and Blacks.

Gastric endoscopic submucosal dissection as a treatment for early neoplasia and for accurate staging of early cancers in a United Kingdom Caucasian population

AIM

To investigate the efficacy of endoscopic submucosal dissection (ESD) at diagnosing and treating superficial neoplastic lesions of the stomach in a United Kingdom Caucasian population.

METHODS

Data of patients treated with or considered for ESD at a tertiary referral center in the United Kingdom were retrieved for a period of 2 years (May 2015 to June 2017) from the electronic patient records of the hospital. Only Caucasian patients were included. Primary outcomes were curative resection (CR) and were defined as ESD resections with clear horizontal and vertical margin and an absence of lympho-vascular invasion, poor differentiation and submucosal involvement on histological evaluation of the resected specimen. Secondary end-points were reversal of dysplasia at 12 mo endoscopic follow-up and/or at the latest follow up. Change in histological diagnosis pre and post ESD was also analysed.

RESULTS

Twenty-four patients were initially identified with intention to treat. 19 patients were eligible after mapping gastroscopy and ESD was attempted on a total of 25 ESD lesions, 4 of which failed and had to be aborted mid-procedure. Out of 21 ESD performed, en-bloc resection was achieved in 71.4% of cases. Resection was considered complete on endoscopy in 90.5% of cases compared to only 38.1% on histology. A total of 6 resections were considered curative (28%), 5 non-curative (24%) and 10 indefinite for CR or non-CR (24%). ESD changed the histological diagnosis in 66.6% of cases post ESD. Endoscopic follow-up in the “indefinite” group and CR group showed that 50% and 80% of patients were clear of dysplasia at the latest follow-up respectively; 2 cases of recurrence were observed in the “indefinite”group. Survival rate for the entire cohort was 91.7%.

CONCLUSION

This study provides early evidence for the efficacy of ESD as a therapeutic and diagnostic intervention in Caucasian populations and supports its application in the United Kingdom.

Comparison of Long-Term Outcomes After Non-curative Endoscopic Resection in Older Patients with Early Gastric Cancer

BACKGROUND

Limited data exist that describe the long-term outcomes from additional surgery following non-curative endoscopic resection (ER) of early gastric cancer (EGC) in older people. This study aimed to determine the appropriate treatment strategy for these patients.

METHODS

We analyzed data from 2895 patients who underwent ER for EGC, of whom 451 (15.6%) had non-curative resections followed by curative surgery or surveillance only. Of these patients, 138 were older (aged ≥70 years). We compared the long-term outcomes of the different treatment strategies in the older patients with non-curative resections for EGC, and the outcomes of each treatment strategy, with those in younger patients.

RESULTS

The older patients underwent curative resections, non-curative resections with surgery, or non-curative resections with surveillance, and the 5-year disease-specific survival (DSS) rates were 100, 100, and 73%, respectively. There was a trend toward significance for DSS in favor of the non-curative resections with surgery group compared with the non-curative resections with surveillance-only group (p = 0.069). Among those who did not undergo additional surgery, the older patients had worse DSS than the younger patients, and patients who underwent additional surgery had better DSS, irrespective of their ages. Multivariable analysis adjusted for other-cause mortality generated similar results. Overall survival and recurrence-free survival did not differ according to treatment strategy, and perioperative morbidity and mortality did not differ significantly according to age.

CONCLUSIONS

In older patients with non-curatively resected EGC, additional surgery demonstrated a trend toward better DSS, and perioperative complications did not increase significantly.

Clinical response to peroral endoscopic myotomy in patients with idiopathic achalasia at a minimum follow-up of 2 years

BACKGROUND

The recently developed technique for peroral endoscopic myotomy (POEM) has been shown to be effective in several short-term studies. Longer term outcome data are largely non-existent.

OBJECTIVE

To systematically report clinical outcome with a minimum post-POEM follow-up of 2 years.

DESIGN

All patients treated consecutively by POEM for achalasia at three centres were retrospectively analysed, with a minimum follow-up of 2 years. The main outcome was the rate of POEM failures (Eckardt score >3) related to follow-up time.

RESULTS

Of 85 patients treated, five (5.9%) cases were excluded due to protocol violation or loss to follow-up; the remaining 80 patients (mean age 44.9 years, 54% men) were followed clinically for 29 months (range 24-41). Initial clinical response was observed in 77 cases (96.3%). Clinical recurrences (later failures) were seen in a further 14 cases (17.7%), accounting for a total failure rate of 21.5%. In a multivariate analysis, age and endoscopic reflux signs were independent predictors of treatment success. Of the 17 failures, eight were among the first 10 cases treated in the participating centres. Reflux-associated sequelae included one case of a severe reflux-associated stricture requiring dilatation, and two patients with minor transient Eckardt score elevations curable by proton pump inhibitor (PPI) treatment. Endoscopic signs of reflux oesophagitis, mostly Los Angeles grade A/B, were seen in 37.5% (37/72) at the 2-year control.

CONCLUSIONS

In this multicentre retrospective analysis, a high initial success rate of POEM is followed by a mid-term recurrence rate of 18%. Reflux oesophagitis, albeit mild, is frequent and should probably be treated by regular low-dose PPI therapy.

TRIAL REGISTRATION NUMBER

NCT 01405417 (UKE study).

Application of robotics in gastrointestinal endoscopy: A review

Multiple robotic flexible endoscope platforms have been developed based on cross specialty collaboration between engineers and medical doctors. However, significant number of these platforms have been developed for the natural orifice transluminal endoscopic surgery paradigm. Increasing amount of evidence suggest the focus of development should be placed on advanced endolumenal procedures such as endoscopic submucosal dissection instead. A thorough literature analysis was performed to assess the current status of robotic flexible endoscopic platforms designed for advanced endolumenal procedures. Current efforts are mainly focused on robotic locomotion and robotic instrument control. In the future, advances in actuation and servoing technology, optical analysis, augmented reality and wireless power transmission technology will no doubt further advance the field of robotic endoscopy. Globally, health systems have become increasingly budget conscious; widespread acceptance of robotic endoscopy will depend on careful design to ensure its delivery of a cost effective service.

Enhancing proficiency in performing endoscopic submucosal dissection (ESD) by using a prototype robotic endoscope

BACKGROUND AND STUDY AIMS

One of the challenges in performing endoscopic submucosal dissection (ESD) is the lack of counter traction during submucosal dissection. MASTER (Master and Slave Transluminal Endoscopic Robot) was designed to allow performance of complex endoluminal procedures using two arms with excellent control. This study aimed to compare the performance of ESD between endoscopists and novices using MASTER.

METHODS

This is a prospective study comparing the differences in performing ESD using MASTER in an ex vivo porcine stomach model among individuals with or without experience in surgery and endoscopy. Multiple standardized lesions of 20 mm(2) were pre-marked on an ex vivo porcine stomach. Each participant received basic training in controlling MASTER before the ESD procedure. The operative time and size of specimen obtained by each participant were noted.

RESULTS

Nine individuals (three ESD expert endoscopists, three ESD non-expert endoscopists, and three non-clinician novices) participated in the experiment. All participants completed the ESD procedure for en bloc resection of standardized lesions using EndoMASTER without perforation. The mean times (mean ± SD) taken by ESD expert endoscopists, ESD non-expert endoscopists, and novices to complete Robotic ESD were 122 ± 58 s, 203 ± 150 s, and 561 ± 496 s, respectively. There was no statistically significant difference in the mean operative time to complete the ESD between the three groups (P = 0.242). When the performance of the six endoscopists was compared to that of the three novices, the endoscopists took an average of 162 ± 111 s to complete the ESD, while the non-clinicians required an average of 561 ± 496 s (P = 0.085).

CONCLUSIONS

There was a trend to shorter operative time when comparing endoscopists to non-endoscopists in performing ESD using MASTER. The use of MASTER enabled the novice without endoscopy experience to complete the ESD procedure.