|Lee, Jung eun|
Submitted to: Cancer Causes and Control
Publication Type: Peer reviewed journal
Publication Acceptance Date: 1/11/2013
Publication Date: 1/23/2013
Citation: Je, Y., Lee, J., Ma, J., Zhang, X., Cho, E., Rosner, B., Selhub, J., Fuchs, C.S., Meyerhardt, J., Giovannuci, E.S. 2013. Prediagnostic plasma vitamin B6 (pyridoxal 50-phosphate) and survival in patients with colorectal cancer. Cancer Causes and Control. 24(4):719-729. Interpretive Summary: For the past twenty years our laboratory has been studying the link between inflammation and inflammatory disease and the concentration of pyridoxal 5-phosphate or PLP in plasma, the active form of vitamin B6. In previous studies we have shown that the lower the level of PLP in plasma the higher the chance for people to be inflicted with colorectal cancer. This study which was done in collaboration with investigators from the school of Public Health at Harvard University examined the possibility that high levels of plasma PLP in patients with colorectal cancer could predict lesser likelihood of mortality as a result of the cancer. However, we found that this was not the case. High levels of plasma PLP were not associated with decreased mortality in these patients.
Technical Abstract: Higher plasma pyridoxal 5'-phosphate (PLP) levels are associated with a decreased incidence of colorectal cancer, but the influence of plasma PLP on survival of patients with colorectal cancer is unknown. We prospectively examined whether prediagnostic plasma PLP levels are associated with mortality among colorectal cancer patients. We included 472 incident cases of colorectal cancer identified in the Nurses' Health Study, the Health Professionals Follow-up Study, and the Physicians' Health Study from 1984 to 2002. The patients provided blood samples two or more years before cancer diagnosis. Stratified Cox proportional hazards models were used to calculate hazard ratios (HR) with 95 % confidence intervals (CI) adjusted for other risk factors for cancer survival. Higher plasma PLP levels were not associated with a significant reduction in colorectal cancer-specific (169 deaths) or overall mortality (259 deaths). Compared with patients who had less than 45 pmol/ml of plasma PLP (median: 33.6 pmol/ml), those who had 110 pmol/ml or higher levels (median: 158.8 pmol/ml) had multivariable HRs of 0.85 (95 % CI 0.50-1.45, p trend = 0.37) and 0.87 (95 % CI 0.56-1.35, p trend = 0.24) for colorectal cancer-specific and overall mortality. Higher plasma PLP levels, however, seemed to be associated with better survival among patients who had lower circulating 25-hydroxyvitamin D(3) levels (<26.5 ng/ml) (p interaction less than or equal to .005). Higher prediagnostic plasma PLP levels were not associated with an improvement on colorectal cancer survival overall. Further research is needed to clarify the influence of vitamin B6 on colorectal cancer progression and survival.