Endoscopic mucosal resection for early gastric cancer

Current role of minimally invasive approaches in the treatment of early gastric cancer

Despite declining incidence, gastric cancer remains one of the most common cancers worldwide. Early detection in population-based screening programs has increased the number of cases of early gastric cancer, representing approximately 50% of newly detected gastric cancer cases in Asian countries. Endoscopic mucosal resection and endoscopic submucosal dissection have become the preferred therapeutic techniques in Japan and Korea for the treatment of early gastric cancer patients with a very low risk of lymph node metastasis. Laparoscopic and robotic resections for early gastric cancer, including function-preserving resections, have propagated through advances in technology and surgeon experience. The aim of this paper is to discuss the recent advances in minimally invasive approaches in the treatment of early gastric cancer.

Clinicopathological characteristics and treatment strategies in early gastric cancer: a retrospective cohort study

Background

Both endoscopic and surgical approaches are employed in the treatment of early gastric cancer (EGC). The aim of this study was to establish appropriate treatment strategies for early gastric cancer.

Methods

We retrospectively examined clinicopathological data of EGC patients who had undergone surgery.

Results

A total of 327 patients (204 males and 123 females, mean age 63.2 years) were eligible for inclusion in the study. The median follow-up period was 31 months. Of 161 mucosal (pT1a) tumors, 87 were mainly undifferentiated and 110 had an undifferentiated component. Four patients with pT1a tumors had lymph node metastases; all these tumors were signet-ring cell carcinomas and were macroscopic type 0-IIc with ulceration, and only one of them had lymphatic invasion. Among patients with submucosal tumors, four of 43 patients with pT1b1 tumors and 37 of 123 patients with pT1b2 tumors had nodal metastases. Lymph node metastases were significantly higher in mixed undifferentiated type group than differentiated type group for both groups, pT1a-pT1b1 (p = 0.0251) and pT1b2 (p = 0.0430) subgroups. Only four of 45 patients with nodal metastases were diagnosed preoperatively by computed tomography (sensitivity 8.9%, specificity 96.2%). Nine patients with pT1b tumors had recurrence after surgery, and died. The sites of initial recurrence were liver, bone, peritoneum, distant nodes, and the surgical anastomosis.

Conclusions

The incidence of nodal metastases was approximately 5% in undifferentiated type mucosal (pT1a) tumors, and higher in submucosal (pT1b) tumors. The sensitivity of preoperative diagnosis of nodal metastases in EGC using computed tomography was relatively low in this study. Therefore at present surgery with adequate lymphadenectomy should be performed as curative treatment for undifferentiated type EGC.

Cost-effectiveness of treatment and endoscopic surveillance of precancerous lesions to prevent gastric cancer

BACKGROUND

Although surveillance for Barrett esophagus and other gastrointestinal precancerous conditions is recommended, no analogous guidelines exist for gastric lesions. The objective of this study was to estimate the clinical benefits and cost-effectiveness of treatment and endoscopic surveillance to prevent gastric cancer.

METHODS

The authors developed a state-transition decision model for a cohort of US men with a recent incidental diagnosis of gastric precancerous lesions (dysplasia, intestinal metaplasia, or atrophy). Strategies included 1) no surveillance or treatment and 2) referral for surveillance and treatment, and varied by surveillance frequency (none, every 10 years, every 5 years, or every year) and treatment modality for dysplastic and cancerous lesions (surgery or endoscopic mucosal resection [EMR]). The term "post-treatment surveillance" was restricted to surveillance of individuals after treatment. Data were based on published literature and databases. Outcomes included lifetime gastric cancer risk, quality-adjusted life expectancy, lifetime costs, and incremental cost-effectiveness ratios.

RESULTS

For a cohort of men with dysplasia aged 50 years, the lifetime gastric cancer risk was 5.9%. EMR with annual surveillance reduced the lifetime cancer risk by 90% and cost $39,800 per quality-adjusted life year (QALY). Addition of post-treatment surveillance every 10 years provided little incremental benefit ( approximately 5%) but cost >$1 million per QALY. Results were most sensitive to surgical risks and the proportion of lesions completely removed with EMR. For intestinal metaplasia, surveillance every 10 years reduced lifetime cancer risk by 61% and cost $544,500 per QALY.

CONCLUSIONS

EMR with surveillance every 1 to 5 years for gastric dysplasia was promising for secondary cancer prevention and had a cost-effectiveness ratio that would be considered attractive in the United States. Endoscopic surveillance of less advanced lesions did not appear to be cost-effective, except possibly for immigrants from high-risk countries.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Gastric cancer

Gastric cancer is the second most frequent cause of cancer death worldwide, although much geographical variation in incidence exists. Prevention and personalised treatment are regarded as the best options to reduce gastric cancer mortality rates. Prevention strategies should be based on specific risk profiles, including Helicobacter pylori genotype, host gene polymorphisms, presence of precursor lesions, and environmental factors. Although adequate surgery remains the cornerstone of gastric cancer treatment, this single modality treatment seems to have reached its maximum achievable effect for local control and survival. Minimally invasive techniques can be used for treatment of early gastric cancers. Achievement of locoregional control for advanced disease remains very difficult. Extended resections that are standard practice in some Asian countries have not been shown to be as effective in other developed countries. We present an update of the incidence, causes, pathology, and treatment of gastric cancer, consisting of surgery, new strategies with neoadjuvant and adjuvant chemotherapy or radiotherapy, or both, novel treatment strategies using gene signatures, and the effect of caseload on patient outcomes.

Transanal endoscopic microsurgery versus endoscopic mucosal resection for large rectal adenomas (TREND-study)

Background

Recent non-randomized studies suggest that extended endoscopic mucosal resection (EMR) is equally effective in removing large rectal adenomas as transanal endoscopic microsurgery (TEM). If equally effective, EMR might be a more cost-effective approach as this strategy does not require expensive equipment, general anesthesia and hospital admission. Furthermore, EMR appears to be associated with fewer complications.

The aim of this study is to compare the cost-effectiveness and cost-utility of TEM and EMR for the resection of large rectal adenomas.

Methods/design

Multicenter randomized trial among 15 hospitals in the Netherlands. Patients with a rectal adenoma ≥ 3 cm, located between 1–15 cm ab ano, will be randomized to a TEM- or EMR-treatment strategy. For TEM, patients will be treated under general anesthesia, adenomas will be dissected en-bloc by a full-thickness excision, and patients will be admitted to the hospital. For EMR, no or conscious sedation is used, lesions will be resected through the submucosal plane in a piecemeal fashion, and patients will be discharged from the hospital. Residual adenoma that is visible during the first surveillance endoscopy at 3 months will be removed endoscopically in both treatment strategies and is considered as part of the primary treatment.

Primary outcome measure is the proportion of patients with recurrence after 3 months. Secondary outcome measures are: 2) number of days not spent in hospital from initial treatment until 2 years afterwards; 3) major and minor morbidity; 4) disease specific and general quality of life; 5) anorectal function; 6) health care utilization and costs. A cost-effectiveness and cost-utility analysis of EMR against TEM for large rectal adenomas will be performed from a societal perspective with respectively the costs per recurrence free patient and the cost per quality adjusted life year as outcome measures.

Based on comparable recurrence rates for TEM and EMR of 3.3% and considering an upper-limit of 10% for EMR to be non-inferior (beta-error 0.2 and one-sided alpha-error 0.05), 89 patients are needed per group.

Discussion

The TREND study is the first randomized trial evaluating whether TEM or EMR is more cost-effective for the treatment of large rectal adenomas.

Trial registration number

(trialregister.nl) NTR1422

Epidemiology of premalignant gastric lesions: implications for the development of screening and surveillance strategies

Gastric cancer is one of the most common cancers worldwide; however, gastric cancer incidence varies greatly between different geographic areas. As gastric cancer is usually diagnosed at an advanced stage, the disease causes considerable morbidity and mortality. To detect gastric carcinomas at an early and curable stage, screening and surveillance seem necessary. Premalignant gastric lesions are well known risk factors for the development of intestinal type gastric adenocarcinomas. In a multistep cascade, chronic Helicobacter pylori-induced gastritis progresses through premalignant stages of atrophic gastritis, intestinal metaplasia and dysplasia, to eventually gastric cancer. Therefore, this cascade may provide a basis for early detection and treatment of gastric cancer. Epidemiology of gastric cancer and premalignant gastric lesions should guide the development of screening and surveillance strategies, as distinct approaches are required in countries with low and high gastric cancer incidences.

Interventional upper endoscopy: the adult perspective

Advances in interventional endoscopic technology and techniques are paving the way for the increased application of minimally invasive methods to treat various upper gastrointestinal conditions, both benign and malignant. Through the description of enteral stenting for palliation of malignant obstruction, expanded techniques of enteral feeding tube placement, mucosectomy of early gastric cancer, and snare ampullectomy for benign ampullary lesions, this review focuses on recent progress in therapeutic endoscopy of the stomach and duodenum and highlights the importance of continued research and development.