Metastatic Gastric Adenocarcinoma
Stage IV
cT3 N2 M1 · Oligometastatic
HER2+ · IHC 3+
MSK New YorkHillel Yaffe, Israel
01 Clinical History
The patient is a 23-year-old woman with no significant prior medical history, initially evaluated at Hillel Yaffe Medical Center (Israel) following complaints of upper abdominal pain and unintentional weight loss. Upper endoscopy revealed a mass in the gastric body. Biopsy confirmed moderately differentiated Gastric Adenocarcinoma. PET-CT identified an oligometastatic pattern with involvement of the lungs, ovary, and liver.
02 Imaging & Scan Findings
PET-CT · Hillel Yaffe · Oct 2025
| Site | Finding | SUVmax | Size |
|---|
| Gastric body | Hypermetabolic mural thickening | | ~4.2cm |
| Lungs (bilateral) | Multiple small nodular foci | | <5mm |
| Left ovary | Focal FDG-avid lesion | | ~8mm |
| Liver (Seg. VI) | Single hypodense lesion | | ~1.1cm |
| Perigastric LN | Mildly enlarged, FDG-avid | | ≤1.5cm |
| Peritoneal cavity | No ascites. No omental cake. | — | — |
MRI Abdomen/Pelvis · Nov 2025 · Pre-chemo Baseline
·Liver (Seg. VI): 1.1cm T2-hyperintense lesion with arterial phase enhancement. Consistent with metastatic deposit. No additional hepatic lesions.
·Left Ovary: 8mm T2-intermediate focus, restricted diffusion (ADC ~650×10⁻⁶ mm²/s). Suspicious for ovarian metastasis (Krukenberg-type).
·Gastric Mass: Transmural thickening 4.2×3.1cm, irregular margins. Invasion limited to perigastric fat (cT3). No invasion of adjacent organs.
·Peritoneal Surface: No peritoneal nodules. Trace free fluid — within normal limits.
·Lymph Nodes: Perigastric nodes up to 1.5cm, morphologically suspicious. No retroperitoneal adenopathy.
Restaging CT · Hillel Yaffe · Jan 2026 — Post 1 Cycle Chemotherapy
| Site | Baseline | Post-1 Cycle | Response |
|---|
| Gastric primary | 4.2cm | ↓ 3.6cm | Stable Disease |
| Lung nodules | <5mm (multiple) | <5mm stable | Stable Disease |
| Liver (Seg. VI) | 1.1cm | ↓ 0.9cm | Minor Response |
| Left ovary | 8mm | ↓ 7mm | Stable Disease |
| Perigastric LN | 1.5cm | ↓ 1.3cm | Stable Disease |
Overall Response: Stable disease with minor hepatic response by RECIST 1.1 after 1 cycle. No new lesion development. Patient transferred to MSK for consolidative SBRT/SGRT.
03 Prior Systemic Treatment · Hillel Yaffe · Jan 2026 · 1 Cycle Completed
Capecitabine (Xeloda)
Fluoropyrimidine prodrug
1000 mg/m² PO BID
14 days on / 7 days off · 21-day cycle
DNA synthesis inhibitor
✓ Well-tolerated. No significant PPE observed.
Trastuzumab (Herceptin)
Anti-HER2 monoclonal antibody
Loading: 8 mg/kg IV
Maintenance: 6 mg/kg IV q3w
Indicated: HER2 IHC 3+
♥ Cardiac ECHO: LVEF >55% preserved.
Ramucirumab (Cyramza)
Anti-VEGFR2 monoclonal antibody
8 mg/kg IV · Days 1 & 15
Each 21-day cycle
Inhibits tumor angiogenesis
BP stable. No dose modifications required.
04 Current Treatment · SGRT / SBRT at MSK · In Progress
Fractions delivered2 of 5 complete (40%)
✓ Treatment commenced March 23, 2026 · No acute toxicity reported · Excellent tolerance
| # | Date | Site Treated | Dose | Status | Notes |
|---|
| 1 | March 23, 2026 | Lung metastases (bilateral) | 10 Gy | ✓ Delivered | DIBH technique. CBCT verification. |
| 2 | March 24, 2026 | Liver metastasis (Seg. VI) | 15 Gy | ✓ Delivered | DIBH technique. CBCT verification. |
| 3–5 | Scheduled | Lung / Ovary (per plan) | Pending | ⏳ Pending | Remaining fractions per planned course. |
Full Planned SGRT/SBRT Course — Target Sites & Doses
| Target Site | Total Dose | Fractions | Dose/fx | Technique | Intent | Rationale |
|---|
Lung Metastases
Bilateral nodules | 50 Gy | 5 fx | 10 Gy/fx | SBRT–VMAT
SGRT-guided | Ablative | Nodules <5mm; DIBH motion mgmt |
Liver (Segment VI)
0.9cm residual | 45 Gy | 3 fx | 15 Gy/fx | SBRT–VMAT
SGRT-guided | Ablative | Single lesion; liver constraints met |
Left Ovarian Metastasis
Small volume pelvic | 40 Gy | 5 fx | 8 Gy/fx | SBRT–IMRT
SGRT-guided | Consolidative | Local consolidation intent |
Concurrent: Trastuzumab maintenance q3w continued · Capecitabine held · Ramucirumab held per MSK protocol · SGRT: AlignRT / Catalyst HD · Sub-millimeter positioning accuracy
05 Monitoring, Follow-Up & Anticipated Side Effects
🫁
Radiation Pneumonitis
Chest CT + pulmonary function at 6 weeks post-SBRT. Low risk — strict V20 lung dose constraints applied.
🔬
Hepatic Toxicity
LFTs monitored weekly during liver SBRT. Mean dose <18 Gy, V15 <700 cc normal liver constraints.
♀
Ovarian / Pelvic Toxicity
Gynecological assessment. Fertility preservation consultation completed prior to systemic therapy initiation.
♥
Cardiac Monitoring (Trastuzumab)
ECHO every 12 weeks. LVEF >50% required for continuation. Cardiology co-management if decline observed.
Imaging Follow-Up Schedule
PET-CT Restaging
Assessment per RECIST 1.1 criteria
MRI Abdomen/Pelvis
Liver & ovarian lesion surveillance
ECHO (Cardiac)
LVEF monitoring — Trastuzumab continuation criteria
Multidisciplinary Tumor Board
MSK GI Oncology + Rad Onc joint review. Coordination with Hillel Yaffe for repatriation planning.
06 Summary & Therapeutic Goals
This 23-year-old patient with HER2-positive metastatic gastric adenocarcinoma in an oligometastatic pattern (lung, ovary, liver) received 1 cycle of triplet systemic therapy at Hillel Yaffe Medical Center (Israel) in January 2026, demonstrating stable disease with minor hepatic response. She was subsequently transferred to Memorial Sloan Kettering Cancer Center for consolidative SGRT/SBRT to all known metastatic sites. Treatment is currently in progress: 2 of the planned fractions have been delivered (March 23–24, 2026) with excellent tolerance and no acute toxicity reported. The treatment strategy reflects an aggressive, potentially curative-intent approach to oligometastatic disease, aiming to achieve durable local control of all active sites while maintaining systemic HER2-directed therapy.