Improvements to treatment strategies for patients with cancers of the upper gastrointestinal tract have produced a large population of people who remain free from cancer recurrence in the long term following treatment.

Surgery is the cornerstone of treatment for patients with these cancers, but while surgical removal of the tumour may offer the best chance of cure, these are major operations associated with specific long term complications. Weight loss and poor nutrition are common problems among patients who attain long-term cancer remission and cure after surgery. The mechanisms underlying these problems are not well understood and therefore treatment options are limited.

Our research has demonstrated increased levels of chemical messengers (gut hormones) released from the gastrointestinal tract after meals in patients who have previously undergone this type of surgery. These chemical messengers play a role in controlling appetite and interest in food, and increased levels after surgery may reduce interest in eating. Understanding the role of gut hormones in the control of appetite may allow us to use certain medications to block gut hormones and hence increase appetite, allowing patients to eat more and regain weight, preventing nutritional problems after surgery.

In this study, the investigators aim to determine whether exaggerated gut hormone secretion causes reduced appetite and interest in food after surgery. The information gained from this study may help us to develop treatments for patients with weight loss and nutritional problems after surgery.

Inclusion criteria:

1. Surgical procedure: Two-stage, three-stage or transhiatal esophagectomy with gastric conduit reconstruction and pyloroplasty, total gastrectomy with Roux-en-Y reconstruction, pancreaticoduodenectomy, or matched healthy unoperated control subjects
2. Disease-free at least one year post-resection

Exclusion criteria:

1. Pregnancy, breastfeeding
2. Significant and persistent chemoradiotherapy and/or surgical complication
3. Other previous upper gastrointestinal surgery
4. Unwell or unable to eat
5. Other disease or medications which may affect satiety gut hormone responses
6. Active and significant psychiatric illness including substance misuse
7. Cognitive or communication issues or any factors affecting capacity to consent to participation
8. History of significant food allergy, certain dietary restrictions
9. Confirmed or suspected residual or recurrent disease after surgery, second primary malignancy
10. Requiring adjuvant chemotherapy
11. Contraindication to octreotide administration
12. History of eating disorder