Inclusion Criteria:  Pathologic anatomic analysis (PAD) confirmed esophageal or gastric cancer Gastrectomy or esophagectomy with curative intent ≥18 years of age Signed informed consent Able to comply with the procedures of the study protocol, in the opinion of the investigator Women of child-bearing potential, defined as all women physiologically capable of becoming pregnant, only after A. leaving a negative result on a highly sensitive pregnancy test, B. are using a highly effective method of contraception during treatment, and C. throughout the study.  Exclusion Criteria:  Non-radical operation (defined by macroscopic assessment) or metastatic disease diagnosed at the time of surgery Complications leading to restrictions in postoperative oral intake Advanced comorbidity with ASA score III or more Bradycardia (defined as resting heart rate of under 60 beats per minute) Chronic obstructive pulmonary disease Chronic liver disease Insulinoma Kidney failure Concomitant medication with: cyclosporine, cimetidine, bromocriptine, quinidine, or terfenadine Known or suspected allergy to octreotide Mental inability, reluctance or language difficulties that result in difficulty understanding the meaning of study participation Pregnant or nursing female Participation or recent participation in a clinical study with an investigational product (within the last 3 months). Previous participation in this study