Research project plan

OMEC-1: Systematic review

Focus on oligometastatic esophagogastric cancer
Outline current evidence on (‘Topics’):
- Definition: how many lesions / organs
- Location: esophageal vs. gastro-esophageal junction vs. gastric cancer
- Time aspect: synchronous vs. metachronous vs. recurrence
- Patient selection
- Treatment goals: cure vs. postpone systemic treatment
- Treatment options: systemic vs. local vs. multimodal
- Treatment outcomes: survival / toxicity / Quality of Life
- (Re-)staging, timing and tools
- Conversion surgery
- Classification of (oligo)metastatic disease (Yoshida/modified GIRCG)
Systematic identification of existing (lack of) evidence and (lack of) consensus per issue.

Distribution of 15 real-life clinical cases of esophageal and gastric cancer, provided by UMC Utrecht and Amsterdam UMC, across OMEC-European experts and the OMEC-board member peers
Asking for local MDT responses on whether the case is considered oligometastatic and what the proposed treatment should be.
All selected patients are in good clinical condition, with no comorbidities, were FDG-PET-staged and have ≤5 metastases.
Evaluation and reporting of varying opinions will be performed as a ground for discussion and content of Delphi rounds (OMEC-3).

Delphi consensus rounds through 2 online survey Delphi rounds and a consensus meeting, resulting in a consensus statement;

The systematic review and consensus reached in OMEC 1-3 will lead to publication of a European multidisciplinary consensus statement and recommendations on the decision-making process for oligometastatic esophagogastric cancer.

The multidisciplinary consensus statement and recommendations on the decision-making process in OMEC-4 will lead to a prospective multidisciplinary prospective registration study.