Gastric cancer (GC), despite its declining incidence, remains a significant global health concern. It is the fifth most common malignancy and the third leading cause of cancer death worldwide. Weight loss is a common symptom at diagnosis, affecting 31-87% of patients. The anorexia-cachexia syndrome, characterized by decreased food intake, weight loss, and muscle wasting, further complicates the condition, leading to increased morbidity and mortality. In GC patients, this syndrome is often caused by obstruction of the upper digestive tract due to the tumor's mechanical effects, resulting in dysphagia, early satiety, nausea, and vomiting.
Nutritional therapy aims to improve nutritional status, metabolism, adherence to antitumoral therapies, quality of life, and overall disease management. Nutritional support is recommended for GC patients undergoing surgery and those with unresectable disease, utilizing oral, enteral (EN), and parenteral nutrition (PN).
Nutritional Assessment and Monitoring
An evaluation of nutritional status, food intake, and disease severity should be performed regularly, at least every 4-8 weeks, to detect any reduction in nutritional status early. Several questionnaires, such as the Nutritional Risk Screening 2002 (NRS 2002) tool, have been developed for the early detection and treatment of malnourished hospital patients. Increased scores on the NRS 2002 are associated with increased rates of postoperative complications and increased length of stay.
The prognostic nutritional index (PNI), calculated using serum albumin value and lymphocyte count, is another tool used to predict the prognosis of patients with gastrointestinal malignancies. A PNI score <45 indicates severe nutritional impairment, while a score ≥45 is associated with normal nutritional status.
Preoperative Nutritional Support
For patients undergoing surgery, preoperative nutritional condition directly affects postoperative prognosis, overall survival, and disease-specific survival. Improving nutritional status before surgery may ameliorate the postsurgical outcome of GC patients. The German S3 Guidelines recommend nutritional support for patients with insufficient dietary intake, defined as an oral food intake <500 kcal/day or ≤75% of the requirement for more than 1-2 weeks.
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In patients with an intact gastrointestinal tract, EN is as effective as PN. EN may be performed through a nasogastric or nasoenteric tube for short periods, whereas direct access to the bowel such as via a jejunostomy should be preferred if EN is given for >3 weeks. A randomized controlled trial (RCT) demonstrated that preoperative EN improves postoperative nutritional status, alleviates the inflammatory response, and facilitates patient recovery.
Immunonutrition
Oral or enteral administration of a nutritional solution enriched with immune-stimulating nutrients (arginine, ω-3 fatty acids, and nucleotides) is called immunonutrition (IN). Perioperative IN significantly reduces overall complications and hospital stay but not mortality. The ESPEN Guidelines, the German S3 Guidelines for GC, and the North American Surgical Nutrition Summit recommend oral/enteral IN for patients with upper gastrointestinal cancer 5-7 days before surgery and through the postoperative period.
Enhanced Recovery After Surgery (ERAS)
Independently of nutritional status, the Enhanced Recovery After Surgery (ERAS) group recommends preoperative carbohydrate loading (800 ml of a 12.5% carbohydrate drink the night before surgery and 400 ml the following morning 2 h prior to induction of anesthesia) to reduce insulin resistance and tissue glycosylation caused by the surgery, help in postoperative glucose control, and sustain normal bowel function.
Postoperative Nutritional Support
The role of postoperative nutritional support is to maintain nutritional status in the catabolic period after surgery. The prevalence of severe malnutrition increases substantially after surgery. After surgical treatment, appetite and diet intake decline during recovery, and nutritional status can take up to 1 year to recover. Small intestinal functions resume between 6 and 12 h after surgery, indicating that EN support could be started at that time. Early oral nutrition after surgery for GC is safe and does not increase the incidence of postoperative complications when compared to EN through a nasogastric tube.
Perioperative nutrition effectively reduces the incidence of postoperative complications in malnourished GC patients. A study showed that perioperative nutrition resulted in a twofold reduction in postoperative complications and a threefold reduction in deaths. The total length of hospitalization and postoperative stay of the control patients were significantly longer than those of the studied patients.
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Specific Nutrient Deficiencies and Management
Anemia is a frequent complication after gastrectomy, with deficiencies in iron, vitamin B12, or folate reported. Anemia develops in 50% of patients who undergo total gastrectomy.
Iron Deficiency
Poor nutritional status and decreased dietary iron intake may lead to iron depletion after gastric surgery. Increased iron depletion may also result from gastrointestinal blood loss at the anastomotic site or from bacterial overgrowth in the blind loops. Alterations in digestion and impaired iron absorption are considered the leading factors contributing to iron deficiency after gastrectomy. Reduced gastric acidity impairs the conversion of nonheme iron (Fe3+) into the more absorbable ferrous form (Fe2+). The treatment of iron-deficiency anemia after gastrectomy requires correction of the deficit in circulating hemoglobin, replenishment of the storage deficit, and correction of any treatable source of abnormal blood loss.
Vitamin B12 Deficiency
Vitamin B12 deficiency can develop as early as 1 year after total gastrectomy. Intrinsic factor, which is mainly produced by parietal cells of the oxyntic gastric glands, is necessary to absorb enteral vitamin B12. Supplementation with vitamin B12 is recommended after surgery. Administration of vitamin B12 is effective both via the subcutaneous and the oral route. Oral vitamin B12 supplementation is effective in increasing the serum vitamin B12 concentration, with prompt resolution of the symptoms related to vitamin B12 deficiency. Oral vitamin B12 replacement therapy provides safe and effective treatment for vitamin B12 deficiency after total gastrectomy in GC patients.
Pancreatic Insufficiency
Pancreatic insufficiency has been proposed as a possible cause of malabsorption following total gastrectomy. However, pancreatic enzyme supplementation did not result in a significant difference between a placebo and an enzyme-treated group regarding bowel habits or fat malassimilation. The effect of high-dose pancreatic enzyme supplementation on symptoms and steatorrhea after total gastrectomy was marginal and did not justify routine use.
Oral Nutrition and Dietary Modifications
Oral nutrition includes diet and oral supplementation. After gastrectomy, a diet based on frequent small meals with limitation of simple carbohydrates, in order to prevent dumping syndrome, is recommended.
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General Dietary Recommendations
- Eat a balanced diet: Modify certain hallmarks of a balanced diet by considering lower fiber, softer fruits, cooked vegetables, and less fibrous lean proteins.
- Minimize processed foods: Cut back on meats such as bacon, sausage, and deli meats, and avoid processed foods including candy, packaged snack foods, soda, and other sweetened beverages.
- Eat smaller, more frequent meals: Try eating six smaller meals a day and maintaining an adequate calorie intake by adding calorie-dense foods.
- Maintain good nutrition: Focus on food choices that provide enough calories, protein, nutrients, and fluids.
Managing Treatment Side Effects
- Nausea and Vomiting: Eat small meals 5-6 times during the day. Snack on dry or bland foods, and try foods with ginger.
- Chewing and Swallowing Difficulties: A speech pathologist can suggest modifications to the texture of your food.
- Dry Mouth: Some chemotherapy drugs and pain medicines can cause dry mouth, mouth ulcers, or change the amount of saliva in your mouth.
- Constipation: Soften stools by drinking 8-10 glasses of fluid a day and eat foods high in fiber.
- Diarrhea: Drink plenty of fluids to avoid becoming dehydrated.
- Heartburn: Eat slowly and take the time to enjoy your meal. Limit or avoid foods that may make heartburn worse.
Dietary Changes After Surgery
Dietary changes have a huge impact on everyone with cancer. It can take a while to get used to changes to your diet and lifestyle. Finding ways to manage your diet and symptom can help you feel more in control of the situation.
- Eat often: You need at least 6-8 small meals each day.
- Choose high-calorie, high-protein foods and fluids: Focus on these meals to meet your nutritional needs.
- Chew foods completely: Ensure foods are in puree form before swallowing.
- Avoid certain foods: Steer clear of foods high in insoluble fiber, gas-producing foods, and foods and drinks with added sugars.
Advanced Gastric Cancer and Nutritional Challenges
Advanced gastric cancer may impact appetite, swallowing, and digestion. It's crucial to maintain weight and energy levels by adjusting the diet and addressing complications.
Dietary Adjustments
- Eat mostly soft foods and liquids: Focus on nutrient-rich foods that can slip by obstructions.
- Eat small meals throughout the day: Consume five to six small meals to meet nutrition goals.
- Get lots of protein, calories, and vitamins: Ensure meals contain the nutrients needed for recovery.
Foods to Avoid
- High-fiber foods: Raw vegetables, lentils, and whole grains.
- Foods that cause acid reflux: Spicy foods, alcohol, chocolate, tomato, garlic, and onion.
- Gassy foods: Beans and cruciferous vegetables like Brussels sprouts.
- Processed foods: Deli meats or chips.
- Greasy, fried foods: Bacon, onion rings, or doughnuts.
- Sugary foods: Candy, baked goods, or fruit juices.
- Caffeinated beverages: Tea or coffee.
- Carbonated beverages: Soda or sparkling water.
Supplements
Consider taking supplements, especially vitamin B12, to improve immune response and support treatment. Other supplements may include iron, calcium, vitamin D, and folate, depending on individual needs.
Sample Meal Plan (Phase 1 After Total Gastrectomy)
- Breakfast: 2 oz. cottage cheese, 2 oz. pureed fruit
- Mid-morning: High-protein smoothie
- Lunch: 2 oz. ground chicken, 2 oz. mashed sweet potato
- Afternoon Snack: Greek yogurt
- Dinner: 2 oz. baked fish, 2 oz. pureed vegetables
- Evening Snack: Protein shake
Additional Considerations
- Dietary Supplements: Talk to your healthcare provider before taking any dietary supplements.
- Food Safety: Ensure that the foods you’re eating are safe to lower your risk for foodborne illnesses.
- Staying Hydrated: Drink plenty of liquids to stay hydrated during cancer treatment.
The Role of a Dietitian
A dietitian can help you choose the right foods and nutrition products. They can also provide guidance on managing symptoms and side effects with nutrition.
Lifestyle Recommendations
- Do some light physical activity: Such as walking, to improve appetite and mood, reduce fatigue, help digestion, and prevent constipation.
- Relax dietary restrictions: Stomach cancer and the associated treatments change how your body functions.
- Plan ahead: For when you feel too tired to cook.
- Keep snacks handy: Eat small meals frequently, e.g. every 2-3 hours.