A 58-year-old woman presents with a 4-month history of epigastric pain radiating to the back, progressive weight loss (12 kg), and new-onset diabetes mellitus (fasting glucose 186 mg/dL). She denies jaundice or changes in stool colour. On examination, she has an epigastric mass palpable on deep palpation. Serum CA 19-9 is 245 U/mL. CT abdomen shows a 4 cm hypoattenuating lesion in the pancreatic body with loss of the fat plane between the tumour and the superior mesenteric artery (SMA). There is no evidence of distant metastases. What is the most appropriate next step in management?

Explanation

## Resectability Assessment and Treatment Strategy ### Tumour Resectability Classification **Key Point:** The loss of fat plane between the tumour and the superior mesenteric artery (SMA) indicates **locally advanced disease** (borderline resectable or unresectable), NOT resectable disease. This mandates neoadjuvant chemotherapy before any surgical attempt. ### Imaging Criteria for Resectability | Resectability Status | Imaging Findings | SMA/Celiac Involvement | Management | |----------------------|------------------|----------------------|-------------| | **Resectable** | Clear fat planes around tumour; no major vessel involvement | No contact or <180° contact | Surgery first (if fit) | | **Borderline Resectable** | Loss of fat plane; <180° contact with SMA/celiac; reconstructible vessel involvement | <180° contact | Neoadjuvant chemo → surgery | | **Locally Advanced (Unresectable)** | >180° contact with SMA/celiac; encasement; distant metastases | Encasement or >180° contact | Palliative chemo ± bypass | | **Metastatic** | Distant organ involvement (liver, peritoneum, lungs) | Variable | Palliative chemo ± supportive care | **High-Yield:** Loss of the fat plane with the SMA is a hallmark of borderline resectability. The NCCN and ASCO guidelines recommend neoadjuvant chemotherapy (typically gemcitabine + nab-paclitaxel or FOLFIRINOX) for 2–3 months, followed by restaging and reassessment for resection. ### Why Neoadjuvant Therapy First? 1. **Downsizing:** Chemotherapy may shrink the tumour and re-establish a fat plane, making surgery feasible. 2. **Systemic disease control:** Addresses micrometastases before surgery. 3. **Improved outcomes:** Neoadjuvant therapy followed by surgery has superior overall survival compared to upfront surgery in borderline resectable disease. 4. **Selection:** Patients who progress during neoadjuvant therapy are spared unnecessary surgery. **Clinical Pearl:** Pancreatic body/tail cancers are typically managed by **distal pancreatectomy and splenectomy** (not Whipple's, which is for head tumours). This patient's tumour is in the body, so distal pancreatectomy is the appropriate resection if deemed resectable after neoadjuvant therapy. ### New-Onset Diabetes in Pancreatic Cancer **Mnemonic: NEW-ONSET DM + WEIGHT LOSS = PANCREATIC CANCER UNTIL PROVEN OTHERWISE** - Pancreatic cancer can cause diabetes by: - Direct destruction of islet cells - Paraneoplastic effect (tumour-derived cytokines) - Chronic pancreatitis (if underlying) - This is a red flag for malignancy, especially in the absence of obesity or family history. ### Treatment Algorithm for Borderline Resectable Pancreatic Cancer ```mermaid flowchart TD A[Pancreatic cancer diagnosed]:::outcome --> B{Resectability assessment}:::decision B -->|Resectable| C[Surgery first if fit]:::action B -->|Borderline resectable| D[Neoadjuvant chemotherapy]:::action B -->|Locally advanced/metastatic| E[Palliative chemotherapy]:::action D --> F{Restaging after 2-3 months}:::decision F -->|Resectable| G[Distal pancreatectomy + splenectomy]:::action F -->|Still unresectable| H[Continue palliative chemo]:::action C --> I[Adjuvant chemotherapy]:::action G --> I E --> J[Supportive care, bypass if needed]:::action ``` ### Why Not Immediate Surgery? Upfront surgery in borderline resectable disease carries high morbidity (anastomotic leak, pancreatic fistula) and does not improve survival if the tumour cannot be completely resected (R0 resection). Neoadjuvant therapy improves the chance of achieving R0 resection and better overall survival. [cite:NCCN Guidelines Pancreatic Cancer 2023; Harrison 21e Ch 297]