When to treat? new trial aims to optimize therapy for oligometastatic esophageal and gastric cancer

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * Age ≥18 years * Ability to provide written informed consent * Histologically confirmed esophageal, gastric or gastroesophageal junction tumor with oligometastatic (M1) disease defined according to the OMEC consensus statement: * One organ with ≤3 metastases or 1 involved extra-regional lymph node station (based on the TNM 8 classification) * ≤3 unilobar liver metastases or ≤2 bilobar liver metastases * ≤ 3 unilateral lung metastases * Unilateral adrenal gland involvement * Metastasis confined to 1 bone structure or 1 soft tissue compartment * Synchronous oligometastatic disease with a resectable primary tumor or metachronous oligometastatic disease (in the event of a locoregional recurrence this should be resectable) * Metastases should be deemed amenable by the international multidisciplinary expert team for radical local treatment * WHO performance status 0-2 * Indication for checkpoint inhibition and/or targeted therapy * PD-L1 with a CPS of 1 or higher as per local clinical practice for immunotherapy use * HER2 overexpression as per local clinical practice for trastuzumab use * Claudin 18.2 overexpression as per local clinical practice for zolbetuximab use. * Any other biomarker that allows targeted therapy in first line approved by EMA * No prior systemic therapy for metastatic disease * CT-scan ≤8 weeks prior to inclusion * Ability to undergo local treatment and start systemic treatment beyond 18 weeks of total systemic treatment. Exclusion Criteria: * Squamous cell carcinoma * Brain metastases * Peritoneal or pleural carcinomatosis * Patients with MSI dMMR * Uncontrolled immunodeficiency (e.g. AIDS) * Peripheral neuropathy \>CTCAE grade 1, precluding start of full dose oxaliplatin treatment * Both organ metastasis and extra-regional lymph node metastasis * Conditions precluding local treatment or systemic therapy for oligometastatic disease: * Serious medical comorbidities precluding local treatment (e.g., interstitial lung disease in patients with pulmonary metastasis) * Clinical or radiological evidence of spinal cord compression or epidural tumor within 2 mm of the spinal cord * Simultaneous other malignancy or previous other malignancy with a disease-free period of \<5 years, except adequately treated non-melanoma skin cancer or in-situ cancers * Uncontrolled (bacterial) infections * Significant concomitant diseases preventing the safe administration of study drugs or likely to interfere with study assessments * Uncontrolled angina pectoris, cardiac failure or clinically significant arrhythmias * Continuous use of immunosuppressive agents equivalent to \>10 mg daily prednisone * Concurrent use of the antiviral agent sorivudine or chemically related analogues, such as brivudine * Pregnancy or breast feeding * Patients (M/F) with reproductive potential not implementing adequate contraceptive measures