Pancreatic Enzyme Replacement Therapy (PERT) in Pancreatic Cancer

Introduction to Pancreatic Exocrine Insufficiency (PEI)

Pancreatic exocrine insufficiency (PEI) is a condition characterized by the inability of the pancreas to produce sufficient digestive enzymes, with primary causes including chronic pancreatitis, relapsing acute pancreatitis, pancreatic ductal adenocarcinoma, cystic fibrosis, and previous pancreatic surgery, which should prompt immediate clinical suspicion of this condition 1
The risk of developing PEI exceeds 80% in patients with chronic pancreatitis and features such as chronic alcohol use, smoking, pancreatic ductal obstruction, atrophy, duct calcifications, and diabetes mellitus 1
Various conditions can cause PEI, including pancreatic ductal adenocarcinoma, particularly in patients with head tumors, total or partial pancreatectomy, diabetes mellitus, and small intestinal bacterial overgrowth (SIBO) 1
The risk of PEI is increased in patients with a history of pancreatic surgery, with total pancreatectomy resulting in 100% development of PEI 1

The fecal elastase test is the most appropriate initial test for suspected PEI, with results indicating good evidence of PEI (<100 μg/g), indeterminate for PEI (100-200 μg/g), or normal pancreatic function (>200 μg/g) 1, 2, 3
The interpretation of fecal elastase test results is as follows:
FE-1 Level Interpretation
<50 μg/g Severe exocrine pancreatic insufficiency (EPI)
<100 μg/g Good evidence of EPI
100-200 μg/g Indeterminate for EPI
>200 μg/g Normal pancreatic function
1, 2, 3
Using serum pancreatic enzymes for diagnosis is not recommended due to poor sensitivity, as stated in the Gut journal 3
Significant pancreatic damage (up to 90% of acinar tissue) must occur before malabsorption symptoms become evident, as reported in the Gut journal 3
It is essential to consider conditions that mimic or overlap with PEI, such as celiac disease, SIBO, and inflammatory bowel disease (IBD), to avoid overlooking non-pancreatic causes 1
The European Society of Gastrointestinal Endoscopy suggests evaluating for SIBO using hydrogen/methane breath testing to rule out other causes of low FPE levels, and screening for celiac disease and checking for liquid stool samples that might cause falsely low FPE levels are also recommended by the American Gastroenterological Association 4, 1

FE-1 Level	Interpretation
<50 μg/g	Severe exocrine pancreatic insufficiency (EPI)
<100 μg/g	Good evidence of EPI
100-200 μg/g	Indeterminate for EPI
>200 μg/g	Normal pancreatic function

The American Gastroenterological Association recommends initiating PERT for all pancreatic cancer patients experiencing diarrhea due to exocrine pancreatic insufficiency (EPI), with an initial dose of 500 lipase units/kg/meal for adults, taken during meals 1
PERT should be taken during meals, not before or after, to ensure maximum effectiveness as enzymes must mix with food in the stomach 1
Initial dosing for PERT is 500 units of lipase per kg per meal for adults, and 250 units of lipase per kg for snacks, with a maximum dose of 2,500 units of lipase per kg per meal or 10,000 units per kg per day, and should be taken during meals to maximize mixing with food and digestion of nutrients 1

The European Society for Clinical Nutrition and Metabolism suggests using pH-sensitive enteric-coated microsphere preparations for PERT 5
Mini-microspheres (1.0-1.2 mm) may have higher efficacy than larger microspheres for PERT 5

A low to moderate fat diet (approximately 30% of total energy intake) is recommended to complement PERT 1
Avoiding very low-fat diets is advised as they may worsen malnutrition 1
Considering smaller, more frequent meals can help manage EPI symptoms 1
For patients with lactose intolerance, limiting dairy products except yogurt and firm cheeses is recommended 6
Avoiding spicy foods, caffeine, and alcohol that can worsen diarrhea is advised 6

For persistent diarrhea despite PERT, adding loperamide (4 mg initially, then 2 mg every 4 hours, maximum 16 mg/day) is recommended 6
For severe cases unresponsive to loperamide, considering octreotide (100 μg three times daily) is suggested 6

Monitoring and supplementing fat-soluble vitamins (A, D, E, K) is essential for patients on PERT 1
Considering nutritional consultation for comprehensive assessment is recommended 7
PERT improves nutritional status, which may enhance tolerance to cancer therapies 7
Proper management of EPI can significantly improve quality of life and potentially survival 1
Regular monitoring should include baseline and follow-up measurements of BMI, quality-of-life assessment, fat-soluble vitamin levels, and dual-energy x-ray absorptiometry (DEXA) scan every 1-2 years 1
Treatment effectiveness should be evaluated through reduction in steatorrhea and GI symptoms, weight gain and improved muscle mass/function, normalization of fat-soluble vitamin levels, and improved quality of life, as recommended by the American Gastroenterological Association 1