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RDN-AP study materials
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RDN-AP: Oncology, Transplant, and Surgical Nutrition

RDN-AP · Work through your exam, one topic at a time.

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Oncology, Transplant, and Surgical Nutrition

This domain tests how you feed patients before, during, and after major physiologic insults, and when aggressive nutrition helps versus harms. It blends cancer cachexia, enhanced recovery pathways, transplant immunosuppression, and postoperative complications.

Cancer

  • ESPEN defines cachexia as weight loss above 5% over six months, or BMI below 20 kg/m² with loss above 2%. Target 25–30 kcal/kg with 1.0–1.5 g/kg protein.
  • Omega-3 fatty acids may help appetite; megestrol acetate improves appetite but carries venous thromboembolism and adrenal suppression risks; corticosteroids give short-term appetite benefit.
  • Parenteral nutrition does not improve outcomes in patients receiving chemotherapy who can eat, and the neutropenic diet is not supported by evidence.

Surgery and enhanced recovery

  • Enhanced recovery pathways: clear fluids up to two hours and solids up to six to eight hours before surgery, carbohydrate loading where appropriate, no routine nasogastric tube, multimodal opioid-sparing analgesia, early oral feeding, and early mobilization.
  • Prehabilitation combines exercise, nutrition optimization, and psychological support for roughly two to four weeks before major surgery.
  • Arginine and omega-3 enriched immunonutrition is advised for major elective surgery in malnourished patients but is not used in sepsis.
  • Wound healing depends on adequate energy, protein, vitamin C, and zinc.

Transplant

  • Hematopoietic stem cell transplant patients with severe mucositis often need parenteral nutrition because enteral feeding is poorly tolerated.
  • After solid organ transplant, watch for weight gain, post-transplant diabetes, and food safety with immunosuppression. Grapefruit interacts with tacrolimus via CYP3A4.

Worked example

A 64-year-old woman with pancreatic cancer has lost 8% of weight in five months and faces a pylorus-preserving resection. Prehabilitation begins two weeks out: 30 kcal/kg and 1.4 g/kg protein, resistance exercise, and immunonutrition taken for five days preoperatively. Postoperatively she starts clear fluids within hours, advances to solid food on day one, and avoids a routine nasogastric tube.

Traps

Mandating a neutropenic diet; giving parenteral nutrition routinely during chemotherapy; delaying oral intake after surgery out of habit; and ignoring chyle leaks, which call for a low-fat, medium-chain triglyceride formula.