Revisiting malignant gastric outlet obstruction: Where do we stand?

Abstract

The scope of management of malignant gastric outlet obstruction is ever-expanding. The therapeutic use of endoscopy is gaining popularity not just owing to its technical advancement and satisfactory patient outcomes. With technical success rates close to 96%, stent placement for palliating gastric obstruction has ensured a median survival of about 2 months post-deployment of gastro-duodenal stents. Understanding the correct concept of palliation is the need of the hour in management. Identifying the right patient for palliation, selecting the appropriate intervention and auditing the outcome are vital in delivering optimal care. Also, newer procedures such as endoscopic gastro-enterostomy offer promising outcomes in palliative care.

Key Words: Gastric outlet obstruction; Stent; Endoscopy; Palliation; Malnutrition

Core Tip: Decision on management of malignant gastric outlet obstruction needs to take into account the questions-why, when and how. The endoscopic management requires to be tailored to the patients’ needs to provide the optimal palliation.

INTRODUCTION

Gastric outlet obstruction (GOO) is noted to be 10%-25% in patients with pancreatic and biliary malignancies[1]. The consequences of GOO, namely nausea, vomiting, and intolerance of oral feed, are troublesome and have a significant negative impact on the health of these patients. Recent advances in technical skills have pushed palliative endoscopic management ahead of the surgical approach in managing malignant GOO, as the outcomes are comparable and non-inferior to the advanced robotic gastro-jejunal bypass. Endoscopic management as a minimal access modality in combination with lower re-intervention, higher success, and reasonable patency rates appears promising and will stand out as a valuable alternative. The technical and clinical success rates are 96-100% and 82-91% for endoscopic placement of stents in malignant GOO[2]. The manuscript briefly overviews the current scenario in managing malignant GOO.

SURGICAL VS ENDOSCOPIC APPROACH

Compared to the endoscopic approach, conventional surgery is more invasive. Life expectancy of less than 2 months, poor general condition, and high risk for surgical intervention are factors acting as natural choices for endoscopic management[3,4]. Technical and clinical success rates were similar among endoscopic and robotic approaches. At the same time, the procedural time, the time to oral intake, and the post-procedure length of stay were significantly shorter in the endoscopy[5]. Although adverse events post-procedure are less in endoscopy, the need for secondary procedures due to stent block is higher. The cost analysis favours endoscopy when secondary procedures are not considered[6].

MALNUTRITION-IMPORTANCE AND EVALUATION

Baseline biochemical laboratory values such as albumin and haemoglobin serve as quick estimates of malnutrition assessment. Serum albumin can be a stand-alone parameter in nutritional evaluation. Low serum albumin levels were indicative of poor performance status. Levels lower than 2.8 mg/100 mL indicate elevated 90-day mortality in these patients. Although cancer cachexia is recognised as an incriminating factor, the low serum albumin levels may also be linked to the poor socioeconomic status of the patient[7].

Pre-designed screening tools such as Global Leadership Initiative on Malnutrition and Patient Generated Subjective Global Assessment are available for use in the ambulatory care of these patients. PGS GA short form is a simple, objective, and effective tool for patients to aid in nutritional assessment. These can serve as a standard guide with good detective value, enabling nutritional support for these patients[8].

LONG TERM OUTCOME

The assessment of quality of life (QOL) is a challenge in malignant GOO, given the morbidity of the cancer progression, difficulty in recruitment, ethical issues and reduced longevity. The prevailing misinterpretations regarding the various aspects of palliation, such as duration of survival, effective control of pain, ability to eat diet and their relative importance in the assessment of the QOL, require review for a better understanding of palliation. The patient's needs and objective measures, such as symptom-free survival, are essential to reframing the appropriate definition of QOL[9].

QOL Questionnaire gastric cancer module (QLQ-STO22) provides an example of a standard estimation of QOL as it includes a comprehensive questionnaire attempting to address and obtain a global overview of the patient symptomatology, which is vital to an objective assessment[10].

ROLE OF CHEMOTHERAPY

Chemotherapy has the benefit of prolongation of life expectancy in malignant GOO. In the setting of stent placement for palliation of obstructive symptoms, chemotherapy has the advantage of preventing tumour growth, which can potentially cause restenosis. Also, the time to progression of tumour advancement is slowed, so there is an advantage of improved and prolonged palliation. However, the downside of chemotherapy is stent migration in about 16%-25%[11], secondary to a decrease in tumour size leading to the loss of the hold of stent grip. Technical innovations to address stent migration include using uncovered stents, winged, partially covered stents, external snare fixation, over-the-scope clips, and endoscopic suture fixation. Initiation of chemotherapy after stenting is advocated as a safe and efficient measure for patients with reasonable functional status[12,13].

INTERVENTIONAL RADIOLOGY

Interventional radiology is an integral part of endoscopic therapy. Placement of a guide wire under fluoroscopy across the site of obstruction is an essential pre-requisite in procedural management. Fluoroscopy plays a role in the successful stent deployment by delineating the length of the obstruction to be overcome and providing guidance to navigate. Endoscopic sonographic guided gastro-enterostomy requires fluoroscopic guidance as an essential accompaniment for the safe and smooth conduct of the procedure[14].

ENDOSCOPIC GASTRO-ENTEROSTOMY

Endoscopic gastro-enterostomy has evolved as a successful means of minimal access procedure, which can be performed either antegrade or retrograde by deploying a lumen-apposing metallic stent. As an advanced endoscopic procedure, it takes advantage of the twin benefits of deploying a stent and achieving a bypass. The procedure can be accomplished by employing techniques such as antegrade endoscopic ultrasound direct method, antegrade endoscopic ultrasound traditional downstream method, antegrade endoscopic ultrasound direct over guidewire method, retrograde endoscopic ultrasound method and endoscopic balloon occluded bypass method. As the technical success rates are over 90%, with minimal complications, these endoscopic procedures are recommended for favourable outcomes[15,16].

FUTURE PROSPECTS

Endoscopic sonography guided gastro-enterostomy combines the benefits of self-expanding metallic stents and surgical gastro-jejunostomy, with the advantage of durable patency, effectiveness lasting longer, technical safety and minimally invasive. Although the procedure has a steep learning curve, it is likely to be the future modality of management[17].

The limitation of the manuscript is that it is not an exhaustive or systematic review, with no original data to expound on the various management options of malignant GOO.

CONCLUSION

Choosing the best route possible, establishing adequate intake, and eliminating specific complaints such as pain are the broad goals of palliating malignant GOO. Implementing the standard approach in conjunction with the patient's needs and the attenders' suitability would be the way to manage these patients. There are glaring lacunae in the available knowledge platforms concerning the malignant GOO, such as the need for standard tools for nutritional assessment, QOL assessment and chemotherapy issues, to name a few. It is essential to address the above concerns to achieve sustainable targets for patients with malignant GOO.

Vilas-Boas et al[18] present an insightful review of malignant GOO, highlighting the knowledge gaps and grey areas, paving the way for future research on the management options.