Higher Post-Operative Serum Vitamin D Level is Associated with Better Survival Outcome in Colorectal Cancer Patients

Abstract

25-Hydroxyvitamin D (25-OHD) may have a prognostic value in colorectal cancer (CRC) patients. However, as 25-OHD concentration is strongly impacted by surgery, it is uncertain what is the most reliable time-point for 25-OHD assessment, pre- or post-operative. Therefore, we examined 515 CRC patients (AJCC I-III) who underwent surgery. Blood samples were collected either pre-operatively (n = 286; median = 1 day before surgery) or post-operatively (n = 229; median = 8 days). Serum 25-OHD concentration was determined by liquid chromatography–tandem mass spectrometry. Association between 25-OHD and survival was tested in the whole cohort, followed by stratified analyses in pre- and post-operatively sampled. Median 25-OHD in the cohort was 36.7 nmol/L and median follow-up time was 5.9 years. There were no differences between pre- and post-operative cohort in age, sex, 25-OHD, AJCC stage, or localization of tumor. After adjustment, higher 25-OHD (>50 nmol/L) was associated with better overall survival only in post-operative (HR = 0.53; 95% CI: 0.33–0.84; P = 0.006), but not in pre-operative cohort (HR = 1.13; 95% CI: 0.77–1.65; P = 0.53). In conclusion, higher post-operative 25-OHD levels were associated with better survival outcome in CRC patients, while no such association was found for pre-operative levels. Time-point of blood collection should be addressed carefully in future research as it might affect the prognostic value of 25-OHD in CRC.

Acknowledgments

This study was within the collaboration in COST action BM1206.

Conflict of Interest

The authors declare no potential conflicts of interest.

Additional information

Funding

This work was supported by the Cancer Research UK Program Grant funding from Cancer Research UK [C348/A18927], and FP7-PEOPLE-2013-CIG SOGVID, project number 631041.