Retinol and tocopherol content in primary and metastatic digestive neoplasms

Recent trials in digestive-tract cancer have produced conflicting results regarding the protective role of liposoluble vitamins. Accordingly, we have undertaken an extensive appraisal of the behaviour of retinol and tocopherol in both human upper and lower digestive neoplasms.

The subjects comprised six healthy controls, 10 patients with symptomatic cholelithiasis, 13 with gastric neoplasms, 12 with colo-rectal neoplasms and 13 with digestive neoplasms and liver metastases. Retinol and tocopherol in the plasma, liver, as well as from secondary malignant nodules of the liver, were determined following a high performance liquid chromatographic technique.

The plasma concentration of retinol was significantly reduced only in some neoplastic groups with respect to the non-neoplastic groups. Plasma tocopherol levels remained almost unchanged and, surprisingly, they were higher even in the neoplastic patients and in relation to total serum lipids. There was a sharp decrease in the liver tissue levels of total, mainly esterified, retinol in both cholelithiasis and neoplastic groups; tocopherol, on the other hand, remained more or less unchanged, except in the liver metastatic nodules, where it increased.

Levels of plasma vitamin and tissue retinol and tocopherol appear to be unpredictable on the basis of the corresponding circulating levels, and this must be taken into account when prescribing dietary and therapeutic regimes.