Pancreatic Cancer: Causes, Symptoms, Diagnosis and Treatment — Overview, Diagnosis & Treatment Options | MyMedicPlus

Pancreatic ductal adenocarcinoma (PDAC) arises from the ductal epithelium of the exocrine pancreas and accounts for approximately 90% of all pancreatic malignancies. It is one of the deadliest human cancers, with an overall 5-year survival rate of approximately 12% — among the lowest of any solid tumor. Approximately 66,000 new cases are diagnosed in the United States each year, and it is the fourth leading cause of cancer death in men and women. The dominant molecular driver is activating KRAS mutation (present in over 90% of PDACs), followed by inactivation of CDKN2A, TP53, and SMAD4 tumor suppressor genes. A dense fibroblastic stroma surrounding the tumor creates an immunosuppressive microenvironment that impedes drug delivery and immune cell infiltration. Most patients present with locally advanced or metastatic disease, making curative resection possible in only approximately 15-20% of cases — a fundamental reason for the dismal prognosis.

Tobacco smoking approximately doubles the risk of PDAC and is the most important modifiable environmental risk factor, responsible for approximately 20-25% of cases. Longstanding type 2 diabetes mellitus is both a risk factor and an early consequence of emerging pancreatic cancer (new-onset diabetes in a non-obese older adult should trigger investigation). Chronic pancreatitis — particularly hereditary pancreatitis from PRSS1 or SPINK1 mutations — confers a cumulative lifetime risk of approximately 40%. Obesity and high-fat diet are additional risk factors. Hereditary PDAC accounts for approximately 10% of cases, with actionable germline mutations in BRCA2 (most common), BRCA1, PALB2, ATM, and mismatch repair genes (Lynch syndrome). KRAS G12D, G12V, and G12R somatic mutations are the universal initiating oncogenic events, now targetable by novel KRAS-specific inhibitors in clinical trials.

Pancreatic cancer produces symptoms that depend critically on the anatomical location of the tumor within the gland. Tumors of the pancreatic head (approximately 60-70% of cases) classically cause painless obstructive jaundice — scleral icterus, yellowing of the skin, dark urine, pale clay-colored stools, and pruritus — due to common bile duct obstruction. Upper abdominal pain or epigastric discomfort that radiates to the back is highly characteristic and results from celiac nerve plexus invasion. Unexplained and progressive weight loss, anorexia, and profound fatigue are common. New-onset diabetes mellitus in a non-obese patient over 50, or unexplained worsening glycemic control in a known diabetic, may precede diagnosis by months. Tumors of the body and tail typically produce no jaundice and present later with back pain, weight loss, and constitutional symptoms, explaining why body/tail tumors tend to be larger and more advanced at diagnosis.

Multiphasic (pancreatic protocol) CT of the abdomen with thin slices and arterial, portal venous, and delayed phases is the standard diagnostic and staging imaging modality. CT defines the relationship of the tumor to critical peripancreatic vasculature — superior mesenteric artery (SMA), superior mesenteric vein (SMV), portal vein, celiac artery — which determines resectability classification: resectable, borderline resectable, locally advanced unresectable, or metastatic. EUS-guided fine needle aspiration (FNA) or fine needle biopsy (FNB) provides cytological or histological tissue confirmation, particularly for borderline resectable or locally advanced tumors before neoadjuvant therapy. CA 19-9 (Lewis antigen-dependent) is the standard serum tumor marker — elevated in approximately 80% of PDAC but not suitable for screening. Germline genetic testing for BRCA1/2, PALB2, ATM, and Lynch syndrome genes is recommended for all patients regardless of age or family history, as it influences treatment selection.

Surgical resection is the only potentially curative treatment for PDAC. The Whipple procedure (pancreaticoduodenectomy) is performed for head tumors; distal pancreatectomy with splenectomy for body and tail lesions; and total pancreatectomy for diffuse gland involvement. Surgical volume at a high-volume center (more than 20 pancreaticoduodenectomies per year) is strongly associated with improved perioperative outcomes and survival. Adjuvant chemotherapy after resection is standard: modified FOLFIRINOX (mFOLFIRINOX: oxaliplatin, irinotecan, 5-FU, leucovorin) or gemcitabine plus capecitabine are evidence-based regimens that improve 5-year OS from approximately 20% to approximately 25-30%. For borderline resectable disease, neoadjuvant chemotherapy with mFOLFIRINOX (and consideration of radiation) before surgery is increasingly practiced. For locally advanced or metastatic disease, FOLFIRINOX or gemcitabine plus nab-paclitaxel are the standard first-line doublets. Olaparib maintenance is approved for germline BRCA1/2-mutated metastatic PDAC after at least 16 weeks of platinum-based chemotherapy without progression (POLO trial). MSI-H/dMMR pancreatic cancers (rare, <2%) respond to pembrolizumab.

Tobacco cessation is the most impactful modifiable preventive measure for pancreatic cancer, reducing risk toward baseline within 10 years of quitting. Maintaining a healthy body weight and limiting alcohol consumption addresses other modifiable risk factors. Control of type 2 diabetes and regular physical activity may have protective effects. Population-level screening is not recommended because no validated non-invasive test exists for early detection in average-risk individuals. High-risk individuals — those with germline BRCA1/2, PALB2, ATM, Lynch syndrome mutations, or familial PDAC with two or more affected first-degree relatives — are recommended surveillance with annual EUS and/or MRI/MRCP starting at age 50 or 10 years before the youngest affected family member (per International Cancer of the Pancreas Screening Consortium guidelines). Genetic counseling should be offered to all patients with PDAC.

New painless jaundice — yellowing of the skin or eyes — in any adult is a medical emergency requiring same-day or next-day evaluation with abdominal CT imaging to exclude pancreatic head cancer and biliary obstruction. Unexplained upper abdominal or back pain combined with significant weight loss and fatigue requires urgent evaluation by an internist or gastroenterologist. New-onset diabetes in a non-obese person over age 50, or unexplained worsening of long-standing diabetes, warrants an abdominal CT to exclude pancreatic pathology. Anyone with a known hereditary risk (BRCA2, Lynch syndrome, familial pancreatitis, or a family history of two or more relatives with pancreatic cancer) should discuss pancreatic surveillance with their physician or a genetic counselor, as high-risk programs can detect early resectable disease.

Overall 5-year survival is approximately 12%, among the lowest of any cancer. Resectable disease after surgery and adjuvant mFOLFIRINOX: approximately 25-30% 5-year survival. Locally advanced unresectable: median survival approximately 12-15 months. Metastatic pancreatic cancer: median survival approximately 11-12 months with FOLFIRINOX or gemcitabine/nab-paclitaxel. Germline BRCA-mutated patients receiving olaparib maintenance demonstrate improved progression-free survival. The prognosis for Pancreatic Cancer: Causes, Symptoms, Diagnosis and Treatment varies depending on severity at diagnosis, the patient's overall health, and how promptly treatment is initiated. With early diagnosis and appropriate management, many patients achieve good outcomes and maintain quality of life. Regular follow-up with healthcare providers is essential to monitor progress, adjust treatment as needed, and detect any complications early. Adherence to prescribed treatments and lifestyle modifications significantly improves long-term prognosis.