Pancreatic Adenocarcinoma

A lethal malignancy — late diagnosis, KRAS dependence, gemcitabine-era chemotherapy, and emerging targeted strategies for BRCA and KRAS-altered tumors

Key Points

• Pancreatic ductal adenocarcinoma (PDAC) has a 5-year survival of ~13% — the lowest of any major solid tumor — due to late detection and chemotherapy resistance.
• Over 90% of PDAC harbor KRAS mutations, making it the most KRAS-dependent cancer; KRAS G12D and G12V are the most common (and are now targetable).
• New-onset diabetes mellitus (type 3c) and acute pancreatitis may be early manifestations of undiagnosed pancreatic cancer.
• CA 19-9 is the primary biomarker but is neither sensitive nor specific; it is best used for monitoring treatment response.
• Only ~20% of patients present with resectable disease; surgical resection (Whipple or distal pancreatectomy) remains the only potentially curative treatment.
• FOLFIRINOX or gemcitabine + nab-paclitaxel are standard first-line regimens for fit metastatic patients; FOLFIRINOX is preferred for good PS.
• Germline BRCA1/2 mutations in ~6% of PDAC patients: olaparib maintenance after platinum-based first-line therapy significantly improves PFS (POLO trial).

Epidemiology & Incidence

Pancreatic cancer is the third leading cause of cancer death in the United States. In 2024, approximately 66,440 new cases and 51,750 deaths were projected, resulting in a case fatality ratio exceeding 75% — the highest of any major malignancy. The 5-year relative survival rate is approximately 13% — slightly improved from the historical 5–7% due to multiagent chemotherapy advances, but still devastating. The incidence of pancreatic cancer has been slowly rising by ~0.5–1% annually over the past decade, in contrast to declining trends for many other cancers. The reason for this rise is not…

Genetic Predispositions & Risk Factors

Approximately 5–10% of PDAC are attributable to known hereditary syndromes: • BRCA1/2: BRCA2 confers ~3–6× relative risk (lifetime risk ~3–5%); BRCA1 confers ~2–3× risk. Clinically important because BRCA-mutated PDAC is platinum-sensitive and eligible for olaparib maintenance (POLO trial). • PALB2: ~5× increased risk; partner of BRCA2. • Lynch syndrome (MMR mutations): Slight risk elevation; rare but MSI-H PDAC responds to pembrolizumab. • Familial pancreatitis (PRSS1, SPINK1, CFTR mutations): Chronic pancreatitis dramatically increases PDAC risk (40× vs. general population for hereditary…

Clinical Presentation

PDAC has an insidious onset with vague, nonspecific symptoms early in the disease course. The majority of tumors are located in the pancreatic head (~60–70%), which causes biliary obstruction early; body/tail tumors are often asymptomatic until large or metastatic. Pancreatic head tumors: • Painless obstructive jaundice — the classic presentation; progressive yellowing of skin and sclera, dark urine (bilirubinuria), acholic (clay-colored) stools, and pruritus. Courvoisier's sign: palpable, non-tender gallbladder in the setting of jaundice (from slow, progressive obstruction — not seen in…

Staging Overview

PDAC is staged using AJCC 8th Edition TNM, but in clinical practice resectability-based staging is used for treatment planning: Resectable: No arterial involvement (CA, SMA, CHA); no venous involvement or ≤180° contact without contour irregularity of the portal vein/SMV. Borderline resectable (BR): Portal vein/SMV involvement >180° or contour irregularity with/without short segment occlusion; abutment of SMA, CA, or CHA ≤180° without extension to aorta or GDA origin. Locally advanced (LA/unresectable): >180° SMA or CA involvement; aortic involvement; unreconstructable venous occlusion.…

Resectable (Stage I–II) Treatment

Only ~15–20% of patients present with resectable disease. Surgical resection offers the only chance of cure, but even after R0 resection, 5-year survival is ~25–30% due to high rates of systemic recurrence. Surgical procedures: • Pancreaticoduodenectomy (Whipple procedure) for pancreatic head/uncinate tumors: en bloc resection of pancreatic head, duodenum, proximal jejunum, CBD, and often gallbladder, with pancreaticojejunostomy, hepaticojejunostomy, and gastrojejunostomy reconstruction. Major procedure with significant morbidity (pancreatic fistula, delayed gastric emptying, bile leak). •…

Borderline Resectable & Locally Advanced Treatment

Borderline resectable PDAC: The goal of neoadjuvant therapy is to increase the probability of R0 resection, treat micrometastatic disease early, and select patients with favorable biology (those who progress through induction chemotherapy are unlikely to benefit from surgery). Neoadjuvant FOLFIRINOX × 4–6 cycles ± chemoradiation (capecitabine-based 50.4 Gy) → restaging → surgical resection if downstaged to resectable. Emerging data from Alliance A021501 and other trials support neoadjuvant approaches. Perioperative gemcitabine + nab-paclitaxel is an alternative. Locally advanced unresectable…

Stage IV (Metastatic) Treatment

~50% of patients present with metastatic PDAC. Median OS for unselected patients on modern chemotherapy is 8–11 months. Systemic therapy goals are disease control, symptom palliation, and modest OS benefit. First-line chemotherapy (PS 0–1): • FOLFIRINOX (oxaliplatin + irinotecan + leucovorin + 5-FU) every 2 weeks: Median OS 11.1 months vs. 6.8 months for gemcitabine alone (ACCORD-11 trial). Preferred for fit patients (PS 0–1, adequate organ function, no significant neuropathy). • Gemcitabine + nab-paclitaxel (Abraxane) every 3 weeks: Median OS 8.5 vs. 6.7 months for gemcitabine alone (MPACT…