The association between 25-hydroxyvitamin D and upper gastrointestinal cancer survival, and modificatory role of weight loss
Fiona O’ Sullivan, Martin Healy, Sinead King, Jacinta O’ Sullivan, John Reynolds, and Lina Zgaga.
Department of Public Health and Primary Care, Trinity College Dublin, Republic of Ireland.
There is a growing body of literature supporting a beneficial role of vitamin D (vitD) in the survival of cancer. Contrary to this however, there is some evidence demonstrating an inverse relationship in oesophageal and gastric cancer. Weight loss in cancer patients has previously been associated with higher mortality. It has also been demonstrated that weight loss is associated with an increase vitD concentration.
The aim of this study was to examine the role of vitD in the survival of gastric and oesophageal cancer in patients particularly investigating the impact of weight loss.
270 blood samples were taken from the Oesophageal and Gastric Centre within the Trinity College Dublin from 2008-2014. There were 215 oesophageal and 55 gastric cancer cases. Serum 25-hydroxyvitamin D (25(OH)D) was measured using liquid chromatography tandem mass spectrometry. 25(OH)D was May-adjusted to account for variances in month of blood draw. Cox regression hazard ratios and Kaplan Meier curves were performed to estimate adjusted hazard ratios (HRs) for cancer-specific and all-cause mortality comparing those with and without weight loss symptoms.
In total, 36% died from disease and 7% died from other causes (median follow up: 2.4 years). 49% experienced weight loss symptoms prior to surgery. Overall, we found that vitD had no significant effect on cancer-specific or all-cause mortality, however there was a suggestive association with those having higher vitD experiencing higher all-cause mortality (HR=1.6, P-val=0.052). During stratified analysis it was found that those who experienced weight loss had significantly poorer survival than those who did not (HR=1.67, P-val=0.02). Moreover, higher VitD concentration was found to be associated with poorer survival in those who lost weight in cancer-specific (HR=4.15, P-val=0.0002) and all-cause mortality (HR=3.67, P-val=0.0001), while it has no effect on those who did not have weight loss symptoms (p-val=0.49 and 0.65, respectively).
The role vitD in the survival of oesophageal and gastric cancer was found to differ depending on weight loss symptoms. Possible mechanisms need to be explored as to why weight loss impacts upon the role of vitD in survival.