Vitamin B12 deficiency after esophagectomy with gastric tube reconstruction.

The absorbtion of vitamin B12 in the human body is a fased process. Extracting
B12 out of nutrition and binding it to Intrinsic Factor (IF) are processes that
take place in the stomach. Furthermoere, IF is produced by cells in the stomach
wall. In patients who undergo a esophagectomy with gastric tube reconstruction
(GTR) for esophageal carcinoma, part of the stomach is removed. Also, a
vagotomy is performed, which reduces the production of gastric acid by the
stomach endothelium.
One of the possible adverse effects of the operation is that, on term, patients
can develop a vitamin B12 deficiency. Possible contributing factors for this
are an absolute shortage of IF or perhaps a shortage of gastric acid, which
will lead to a reduced extraction of vitamin B12 out of nutrition.
Earlier studies already showed an increased prevalence of vitamin B12
deficiency in patients who underwent gastric reduction surgery because of
morbid obesity.
Vitamin B12 deficiencies can be symptomatic, in most cases resulting in a
reversible macrocytic anemia, but can also result in irreversible neurological
damage. Nowadays, screening for vitamin B12 deficiency in patients after
esophagectomy with GTR is not common practice.
For this study, we hypothesized that there is a higher prevalence of vitamin
B12 deficiency in patients who underwent esophagectomy with GTR.

Objective of this study is to determine the prevalence of vitamin B12
deficiency among patients who underwent esophagectomy with GTR. The following
specific research questions heve been defined:
- What is the prevalence of vitamin B12 deficiency in patients with esophageal
carcinoma prior to esophagectomy?
- What is the prevalence of vitamin B12 deficiency in patients after
esophagectomy with GTR?
- In what period after esophagectomy do patients develop a vitamin B12
deficiency?
- How many of the found deficiencies are symptomatic and thus need immediate
vitamin B12 suppletion?

Prospective, multi center study.

Patients who are visiting the outpatient clinic in follow-up after undergoing
esophagectomy with GTR or patients placed on the waiting list for this
procedure will be asked to participate in the sudy. If patients decide to
participate, a blood sample will be taken during follow-up in the out-patient
clinic. These samples will be investigated for vitamine B12 deficiency.
Patient who are included in the study before their operation will also donate
three blood samples on the day of admission before operation.
Furthermore, patients will be required to fill in a questionnaire to provide
insight in their diatary intake of vitamin B12.

Patient's participation will stop in case of:
1. A vitamin B12 deficiency is found in the patient.
2. A patient has completed the 5 year follow up after his/her esophagectomy.

In case a vitamin B12 deficiency is found in a patient, he/she will be referred
back to his/her General Practitioner for further treatment.

The burden on patients hwo participate in the study will be limited to the
out-patient clinic visits that will be prolonged by 5 minutes per visit, the
time that is needed to take the extra blood samples.