Colorectal cancer and vitamin D level

Abstract

This study aimed to evaluate vitamin D levels in patients with CRC. The research was a randomized, double-blind, placebo-controlled vitamin D supplementation experiment in patients undergoing elective CRC surgery. Secondary outcomes including complication incidence, hospital time, post-operative rehabilitation and survival were assessed.

Of the 117 patients assessed for eligibility 58 patients were excluded from the study and 59 patients were randomised. Of the 58 patients excluded, 36 did not meet the inclusion criteria and 22 were excluded for other reasons. These include tumour considered too small for study sample (eight), inadequate time available between notification and surgery (six), study staff unavailable (six) and other logistical reasons (two). In the control arm both tumour and normal tissue samples were collected from 25 of the  30 patients. Of the other five patients, one did not proceed to surgery, the resected tissue  of one patient was erroneously placed in formalin in theatre, and the pathologist was  not able to provide a tumour sample in the remaining three.

Of the 29 patients recruited to the treatment arm, both tumour and normal tissue
samples were collected from 26. The pathologist was unable to provide a tumour sample for three patients. Normal tissue was collected for all but one patient, as staff did not request the normal sample.

This randomized clinical study reported possibly important biological variations between vitamin D and placebo classes. Compared to untreated patients, the fatty acid synthesis and fatty acid beta-oxidation pathways were down-regulated in the patient's tumor tissue. Down-regulation of tumor fatty acid metabolism can delay tumor development. Unmetabolized butyrate (short-chain fatty acid used by colon epithelia) may also precipitate decreased cell proliferation, increased differentiation and apoptosis. Further analysis is needed to clarify the effect of vitamin D on colorectal cancer biology.