Introduction: The association of vitamin D deficiency with many chronic diseases worldwide is well known. Nevertheless, it has not been convincingly shown in randomised controlled trials that diseases can be controlled or prevented by having optimum or higher vitamin D levels. The available experimental data on vitamin D and its metabolites suggest that it has beneficial effects on the prevention or treatment of various cancers and other diseases. Many investigations of the aetiopathogenesis and treatment of upper GI malignancies have been performed, but investigations of the vitamin D and treatment of deficiency in cancer patients is not a priority. This may be due to the lack of convincing evidence despite many snap shot observational vitamin D trials in patients with upper GI cancers that have yielded conflicting results. Therefore the impact of vitamin D on the survival or patients' quality of life remains unclear. However, there have been a few observational trials that support the positive correlation of vitamin D levels and the survival of colorectal cancer patients.
Methods: Broomfield Hospital is the regional upper GI cancer centre in Essex and has five upper GI surgeons and this study was carried out involving three surgeons. We prospectively investigated the vitamin D levels in patients who presented for staging of upper GI cancer and for assessment of the possibility of future curative resection or at the time of curative cancer resection to identify the prevalence of deficiency and its impact on the patient outcome. If the disease was found to be non-progressive at the staging, the patients were given a timeframe for a curative procedure. During this time, most of the patients were treated with chemotherapy and were prepared for the operation through the anaesthetic preoperative assessment clinic and were given an exercise program. In cases of progressive disease, appropriate palliative procedures were performed to improve the patients' quality of life.
Results: A total of 50 patients (39 male and 11 female) were investigated and two samples were excluded due to repeated investigations. Based on the Endocrine Society Clinical Guidelines, vitamin D levels were deficient in 21 (42%), insufficient in 22 (46%), and adequate in five (12%) patients. The vitamin D values ranged from 23 nmol/L to 121 nmol/L. The majority of patients (37) underwent therapeutic tumour resections, but ten patients did not undergo operations owing to the presence of distal metastasis of the cancer or poor clinical fitness. We found no significant differences in the vitamin D levels between the surgically treated and inoperable groups using the t-test (p= 0.22). First year mortality was twenty nine percent in the operated group and thirty percent in the inoperable group.
Conclusion: The prevalence of vitamin D deficiency or insufficiency is high in upper GI cancer patients. The single sample of vitamin D may not reflect the patients' long term vitamin D status, therefore snap shot investigations of vitamin D levels are of limited value in forecasting the disease prognosis.