Vitamin D supplementation prior to surgery for colorectal cancer: a randomised pilot study.
Ontology highlight
ABSTRACT: Interventions: Colorectal cancer patients scheduled to undergo routine elective surgery at Dunedin Hospital will be randomised to receive either a single oral 5mg dose of vitamin D3 (cholecalciferol), or identical placebo to be taken 7-21 days prior to surgery.
A dose of 5mg of vitamin D3 will consistently achieve therapeutic serum levels >80nmol/L, peaking at 1 week and gradually falling thereafter. The dose is safe and designed to rapidly achieve desirable levels without delaying surgery.
All patients enrolled will recieve all other treatment and care as they would have otherwise done so.
Primary outcome(s): A significant increase in the expression of genes containing the Vitamin D responsive element (VDRE), in tumour tissue, in patients receiving active study medication compared to placebo.
Previously published data on the effects of vitamin D on gene expression in a colorectal cancer cell line will be used to identify genes that are responsive to vitamin D. Affymetrix microarray data from these experiments are available from the NCBI GEO database under the accession number GSE444. In addition, genes representing vitamin D targets in normal colon tissues will be identified by searching publically available colon array databases for expressed genes which contain the VDRE. The VDRE element is present within the promoter region of genes activated by vitamin D and therefore acts as a convenient tag to identify vitamin D responsive genes.
RNA will be isolated from CRC samples from 50 patients, half of whom will have received vitamin D. RNA expression profiles of the 50 tumour RNA samples will then be generated in the Otago Genomics Facility using Affymetrix HG-U133+2.0 GeneChips. Evidence of activation of vitamin D pathways in the tumours from treated and untreated patients will be determined using the vitamin D responsive genes identified above. This will be accomplished by generating a vitamin D meta-gene to represent the coordinated expression of these genes across all tumours, so that tumours exhibiting a molecular response to vitamin D will have high levels of the meta-gene. This meta-gene will then be tested for association with treatment status, as well as clinicopathological (e.g. tumour stage, histology etc), molecular (e.g. proliferation) and immune reponse variables.[Tissue samples will be collected on the day of surgery. These will be batched and analysed in the laboratory within 6 months of the final patients surgery.];A significant difference between treatment groups with respect to macrophage activation against tumour tissue and their ability to prime T cells.
Macrophages isolated from the blood and tumour tissue of CRC patients will be infected with bacterial pathogens in vitro and their ability to destroy these agents measured by quantifying nitric oxide production using the Greiss reaction. Their ability to prime the adaptive immune response will also be measured by analysing activation of T cells recovered from patient tissues using flow cytometry of surface activation markers. Results will be compared between treatment and placebo groups.[Tissue samples will be collected on the day of surgery. These will be batched and analysed in the laboratory within 6 months of the final patients surgery.]
Study Design: Purpose: Treatment; Allocation: Randomised controlled trial; Masking: Blinded (masking used);Assignment: Parallel;Type of endpoint: Bio-availability
DISEASE(S): Colorectal Cancer,Cancer-bowel-back Passage (rectum) Or Large Bowel (colon)
PROVIDER: 2456306 | ecrin-mdr-crc |
REPOSITORIES: ECRIN MDR
ACCESS DATA