A 58-year-old man from rural Maharashtra presents with progressive dysphagia, early satiety, and weight loss of 8 kg over 3 months. Upper endoscopy reveals a large ulcerated lesion in the gastric antrum with surrounding erythema. Multiple biopsies are taken. What is the most appropriate next investigation to assess the extent of local invasion and distant metastases before surgical planning?

Explanation

## Investigation of Choice for Gastric Cancer Staging **Key Point:** Contrast-enhanced CT (CECT) of chest, abdomen, and pelvis is the standard first-line imaging modality for staging gastric cancer after histological confirmation. ### Role of Each Investigation in Gastric Cancer | Investigation | Primary Role | Timing | Limitation | |---|---|---|---| | **CECT chest/abdomen/pelvis** | Assess T stage (wall invasion), N stage (regional nodes), M stage (distant metastases, peritoneal deposits, ascites) | After histology confirmed | Limited sensitivity for small peritoneal deposits (<5 mm) | | **EUS** | Precise T staging (wall layers), local N staging | Before surgery if T1/T2 suspected | Cannot assess distant metastases or distant nodes | | **Staging laparoscopy** | Detect occult peritoneal metastases, assess resectability | Selected cases (locally advanced) | Invasive; reserved for high-risk patients | | **PET-CT** | Detect distant metastases (bone, liver, brain) | Adjunct in advanced disease | Low sensitivity for primary tumor and regional nodes | **High-Yield:** CECT is the **single most important imaging** for treatment planning in gastric cancer. It determines resectability, guides neoadjuvant therapy decisions, and identifies patients with M1 disease (contraindication to surgery). ### Staging Algorithm for Gastric Cancer ```mermaid flowchart TD A[Gastric lesion on endoscopy]:::outcome --> B[Biopsy for histology]:::action B --> C{Histology confirmed?}:::decision C -->|Yes| D[CECT chest/abdomen/pelvis]:::action D --> E{Resectable?}:::decision E -->|Yes, locally advanced| F[Consider EUS for T staging]:::action E -->|Yes, fit for surgery| G[Proceed to surgery]:::action E -->|No, M1 disease| H[Palliative chemotherapy]:::outcome F --> I[Consider neoadjuvant therapy]:::action I --> G ``` **Clinical Pearl:** In a patient with confirmed gastric cancer and no obvious distant metastases on CECT, staging laparoscopy may be considered preoperatively to detect occult peritoneal disease (present in ~10–15% of cases) that would change management from curative to palliative intent. **Mnemonic: CECT-First (C-E-C-T)** — **C**hest/abdomen/pelvis, **E**xamine for **C**urative resectability, **T**hen decide therapy. [cite:Harrison 21e Ch 297]