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11Gastric & Oesophageal

Snapshot. TWO diseases in one anatomical corridor — HISTOLOGY IS THE FIRST FORK. SQUAMOUS CELL (SCC) — upper/mid oesophagus, tobacco/alcohol-driven, highly radiosensitive → definitive chemoradiation is genuinely CURATIVE, not palliative. ADENOCARCINOMA — distal oesophagus / gastro-oesophageal junction (GOJ) / stomach, from reflux–Barrett's or H. pylori–atrophic gastritis, surgery-anchored. Five biomarkers gate first-line systemic therapy: HER2 · PD-L1 · MMR/MSI · Claudin 18.2 · EBV.
Workup
Endoscopy + multiple biopsies → SCC vs adenocarcinoma, the master split (+ Siewert type for GOJ) · EUS (endoscopic ultrasound) — separates T1a (mucosal, endoscopic resection) from T1b (submucosal, needs surgery) · CT chest/abdo/pelvis + FDG-PET/CT for distant disease · STAGING LAPAROSCOPY + peritoneal washings — mandatory for ≥cT1b/T3–4 or node-positive gastric and Siewert III disease BEFORE any curative plan; a positive wash ALONE = M1 — this is the single most decision-changing test in gastric cancer, and skipping it is the commonest avoidable error (a futile laparotomy) · biomarkers at diagnosis: HER2, PD-L1, MMR/MSI, Claudin 18.2, EBV (FGFR2b/bemarituzumab — early OS signal did not hold up on longer follow-up, FORTITUDE-101; not yet an actionable biomarker) · nutrition/functional assessment (weight loss %, albumin, sarcopenia) — decides fitness for trimodality therapy · diffuse/signet-ring histology, age <50, or family history → CDH1 referral.
Treatment by setting
SettingTreatment
HGD or T1a MUCOSAL
≤2 cm, well/moderately differentiated, no ulceration, no LVI
ENDOSCOPIC RESECTION (EMR / ESD) — preferred over oesophagectomy or gastrectomy
Barrett's-related → endoscopic resection of the visible lesion + RFA ablation of the residual Barrett's segment
⚠ T1b (submucosal), poor differentiation, or LVI → formal resection nodal risk rises steeply
RESECTABLE OESOPHAGEAL SCC
Neoadjuvant chemoradiation → oesophagectomy (CROSS) carboplatin AUC2 + paclitaxel 50 mg/m² weekly ×5 with 41.4 Gy in 23 fractions, then surgery
SCC is the radiosensitive histology pCR 49% (vs 23% in adenocarcinoma); median OS 81.6 vs 21.1 months
Because of that, definitive chemoradiation is a legitimate curative alternative see the organ-preservation row below
RESECTABLE OESOPHAGEAL / GOJ ADENOCARCINOMA
① Perioperative FLOT (FLOT4) docetaxel + oxaliplatin + 5-FU/leucovorin, 4 cycles pre- and 4 post-op; median OS 50 vs 35 months · ESMO increasingly favours this for GOJ / gastric-type adenocarcinoma
② Neoadjuvant chemoradiation → surgery (CROSS)
⚠ A genuine NCCN-vs-ESMO divergence, unresolved by head-to-head data NCCN lists both
RESECTABLE GASTRIC ADENOCARCINOMA
Perioperative FLOT (FLOT4) + D2 lymphadenectomy at a high-volume centre
⚠ If they went straight to surgery with a D0/D1 resection and no perioperative chemo → adjuvant chemoradiation (INT-0116) 5-FU/leucovorin + 45 Gy; median OS 36 vs 27 months, but poorly tolerated — 32% grade 4 toxicity, 31% did not complete
After an adequate D2 resection it adds little (ARTIST) reserve it for the under-staged / under-resected patient
AFTER neoadjuvant chemoRT — RESIDUAL pathological disease
i.e. not ypT0N0
Adjuvant nivolumab ×1 year (CheckMate-577) median DFS 22.4 vs 11.0 months
⚠ OS difference did NOT reach significance — this is a DFS-based standard
🔴 ORGAN PRESERVATION — inoperable, declines surgery, cervical oesophagus, or SCC choosing preservation
DEFINITIVE CHEMORADIATION (RTOG 85-01) cisplatin + infusional 5-FU concurrent with RT · 5-year OS 26–27% vs 0% for radiotherapy alone
DOSE — DO NOT ESCALATE: 50.4 Gy in 28 fractions is the standard (INT-0123) / (RTOG 94-05) tested escalation to 64.8 Gy and found NO gain — no survival difference, no better locoregional control, no QoL benefit
In SCC, definitive chemoradiation may equal preoperative chemoRT + surgery NCI PDQ
⚠ Locoregional failure is the weak point ~25% persistence, ~21% recurrence → these patients need structured endoscopic surveillance, not discharge
Salvage oesophagectomy for local persistence / isolated recurrence in fit patients at high-volume centres
🔴 PERITONEAL-POSITIVE M1
staging laparoscopy: visible deposits OR positive cytology alone
Systemic therapy as for M1 — curative resection is NOT indicated
⚠ CRS/HIPEC remains INVESTIGATIONAL trials only, at peritoneal-malignancy centres — (PHOENIX-GC) showed no OS difference; (GASTRICHIP) ongoing
Positive cytology with no visible disease a distinct, better-prognosis subgroup — practice varies
METASTATIC — FIRST LINE, biomarker-directed
interrogate in this order
① MSI-H / dMMR → pembrolizumab (KEYNOTE-158) ORR 30.8% · ⚠ MSI status should also change your LOCALISED plan — perioperative chemotherapy does not improve survival in dMMR/MSI-H gastric cancer
② HER2-positive → trastuzumab + chemotherapy (ToGA) IHC 3+, or 2+ with ISH amplification · add pembrolizumab if CPS ≥1 (KEYNOTE-811)
③ HER2-negative + Claudin 18.2-positive → zolbetuximab + CAPOX/mFOLFOX6 (SPOTLIGHT) (GLOW) moderate-to-strong (2+/3+) membranous staining in ≥75% of cells · FDA-approved Oct 2024
④ HER2-negative adeno → nivolumab + FOLFOX/CAPOX (CheckMate-649) NCCN category 1 at CPS ≥5; median OS 14.4 vs 11.1 months · ⚠ DIVERGENCE: ESMO/EMA restrict to CPS ≥5; NCCN allows CPS 1–4 as category 2B · or pembrolizumab + chemo (KEYNOTE-859) at CPS ≥1
⑤ Oesophageal SCC → nivolumab + chemo OR nivolumab + ipilimumab (CheckMate-648) ⚠⚠ scored as TUMOUR-CELL PD-L1 ≥1%, NOT CPS — a different denominator and an easy, dangerous error · or pembrolizumab + chemo (KEYNOTE-590), benefit concentrated at CPS ≥10
⚠ REGULATORY — affects every PD-1 row above
⚠ June 2025 — FDA NARROWED pembrolizumab and nivolumab labels to PD-L1 CPS ≥1 in advanced gastric / GOJ / oesophageal cancer, following a September 2024 ODAC vote that benefit did not outweigh risk in PD-L1-negative disease — the older all-comers approvals no longer stand
⚠ "PD-L1 positive" is NOT a category always state the NUMBER and the ASSAY (CPS vs tumour-cell %)
SECOND LINE
Ramucirumab + paclitaxel (RAINBOW) median OS 9.6 vs 7.4 months — the standard doublet
Taxane-unfit or neuropathic → ramucirumab alone (REGARD)
HER2-positive → trastuzumab deruxtecan (DESTINY-Gastric04) now the new standard in this line, beating ramucirumab+paclitaxel head-to-head (30% reduction in risk of death; median OS 14.7 vs 11.4 months)
⚠ Re-test HER2 at progression where feasible — it can be lost
THIRD LINE +
Trifluridine/tipiracil (TAGS) median OS 5.7 vs 3.6 months · irinotecan is an accepted alternative
CDH1 CARRIER — hereditary diffuse gastric cancer, no cancer yet
Prophylactic total gastrectomy, conventionally from age 20 guideline range 20–30
If deferred → annual surveillance endoscopy with multiple random biopsies (Cambridge protocol) from age 40, or 10 years before the youngest family case
Women also need breast MRI from age 30 lobular breast cancer risk
⚠ Counsel with CURRENT figures cumulative advanced gastric cancer risk by age 80 is ~10.3% (men) / 6.5% (women) — far lower than the historic 70–80% estimates, and it materially changes the consent conversation
RISK REDUCTION & EMERGENCIES
H. pylori is a causal risk factor — test and eradicate including in first-degree relatives, and after endoscopic resection of early gastric cancer
Malignant dysphagia → self-expanding metal STENT is the fastest palliation palliative RT 20 Gy/5 or 30 Gy/10 · intraluminal brachytherapy gives longer dysphagia-free survival where life expectancy is longer
⚠ NEVER place a PEG in a potential oesophagectomy candidate it compromises the gastric conduit — use jejunostomy or an NJ tube
Bleeding tumour → endoscopic haemostasis, haemostatic RT, or embolisation
Surveillance
History, examination, symptom-directed review every 3–6 months for 2 years, then 6–12 monthly to 5 years; imaging as clinically indicated (routine intensive imaging has no proven survival benefit). ENDOSCOPIC surveillance is MANDATORY after endoscopic resection or definitive chemoradiation — both leave the organ in situ (for T1a/HGD managed endoscopically: every 6 months for 3 years, then annually). After gastrectomy: nutritional review, iron/vitamin D, and LIFELONG parenteral vitamin B12 (intrinsic factor is gone). Cascade genetic testing of relatives if CDH1. (⚠ The precise society surveillance schedule for this disease could not be verified — confirm against current NCCN.)
Watch
NUTRITION IS THE SILENT KILLER OF CURATIVE INTENT — sarcopenia and >10% weight loss predict failure to complete perioperative chemotherapy and post-operative death. Dietitian from diagnosis, not at the first complication. ⚠ PD-L1 ASSAY CONFUSION IS A LIVE SAFETY ISSUE — CPS (adenocarcinoma) and tumour-cell % (oesophageal SCC) are DIFFERENT denominators. A "PD-L1 positive" report with no number and no method is uninterpretable. FLOT → neutropenia, cumulative oxaliplatin neuropathy (assess before every cycle — it determines taxane eligibility years later), diarrhoea. Check DPYD before any fluoropyrimidine. Trastuzumab deruxtecan → INTERSTITIAL LUNG DISEASE / pneumonitis — can be fatal; baseline and serial imaging, hold for any new respiratory symptom, never rechallenge after grade ≥2. Cisplatin → nephro/oto-toxicity (baseline audiometry), high emetogenicity. Ramucirumab → hypertension, bleeding, perforation, impaired wound healing (hold around surgery). Anastomotic stricture, chronic reflux and conduit dysfunction after oesophagectomy are lifelong and under-treated.
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