A 62-year-old woman from Mumbai with a 2-month history of epigastric pain, weight loss (5 kg), and new-onset diabetes mellitus is found on contrast-enhanced CT to have a 3.5 cm mass in the pancreatic body with encasement of the superior mesenteric artery (SMA) and splenic vein thrombosis. CA 19-9 is 320 U/mL. There is no evidence of distant metastases. What is the most appropriate next step in management?

Explanation

## Clinical Context This patient has **locally advanced pancreatic cancer** (LAPC): - Tumour in pancreatic body with **SMA encasement** (vascular involvement = unresectable by standard criteria) - Splenic vein thrombosis (venous involvement) - No distant metastases (M0) - Elevated CA 19-9 The presence of **arterial encasement (SMA)** makes this **unresectable at presentation**, but the **absence of metastatic disease** makes the patient a candidate for **conversion therapy** via neoadjuvant chemotherapy. ## Neoadjuvant Chemotherapy Strategy **Key Point:** In **locally advanced, non-metastatic pancreatic cancer**, neoadjuvant chemotherapy is the standard of care. The goal is to: 1. Downstage the tumour and potentially resolve vascular involvement 2. Assess tumour biology (response predicts prognosis) 3. Allow time for micrometastases to declare themselves 4. Enable conversion to resectable disease in 10–15% of patients **High-Yield:** **FOLFIRINOX** (5-FU, leucovorin, irinotecan, oxaliplatin) or **gemcitabine + nab-paclitaxel** are the preferred regimens for LAPC. FOLFIRINOX is more aggressive but offers superior OS in fit patients; gemcitabine + nab-paclitaxel is an alternative. ## Resectability Criteria & Vascular Involvement | Vascular Status | Resectability | Management | |---|---|---| | No involvement | Resectable | Upfront surgery | | Venous involvement (SMV/PV) | Borderline resectable | Neoadjuvant ± upfront surgery | | Arterial involvement (SMA/celiac) | **Locally advanced (unresectable)** | **Neoadjuvant chemotherapy** | | Distant metastases | Metastatic | Palliative chemotherapy | **Clinical Pearl:** SMA encasement = **locally advanced**, not borderline resectable. Borderline resectable typically involves SMV/portal vein involvement without arterial encasement. ## Management Algorithm for LAPC ```mermaid flowchart TD A[Locally advanced pancreatic cancer<br/>SMA encasement, no metastases]:::outcome --> B[Neoadjuvant chemotherapy<br/>FOLFIRINOX or Gem+nab-pac]:::action B --> C[Restaging CECT after 2–3 months]:::action C --> D{Conversion to resectable?}:::decision D -->|Yes| E[Curative resection]:::action D -->|No| F{Chemotherapy response?}:::decision F -->|Good response| G[Continue chemotherapy ± radiation]:::action F -->|Poor response| H[Switch regimen or palliative care]:::action ``` **Mnemonic:** **LAPC → NAC → Restage → Resect** (if possible) — Locally Advanced Pancreatic Cancer → Neoadjuvant Chemotherapy → Restaging → Resection.