Vitamin A status and bladder cancer.

Serum retinol, retinol-binding protein (RBP), carotenoids, pre-albumin, zinc and copper were measured in a total of 111 patients. Of these 22 men and 9 women (mean age 68.4 years) had transitional cell carcinoma of the bladder, 29 men and 6 women (mean age 68.8 years) had no recurrence of bladder cancer detected at cystoscopy and 24 men and 5 women presented with non-malignant urological diseases. A further group of 16 patients, 14 of whom had a malignancy at some other site, with a mean age of 73.1 years constituted a miscellaneous group. There were no significant differences between any of the groups in serum concentrations of any of the constituents measured. However, serum concentrations of retinol, carotenoids and RBP were significantly lower in a small group of patients with invasive bladder cancer than in patients with non-invasive disease. Similarly, serum concentrations of the same constituents were lower in patients with poorly differentiated tumours. Estimates of retinol and carotenoid intake made by questionnaire showed that these low values were not due to lower intake. The results of this study do not support the suggestion that high dietary intakes of retinol or carotenoid--containing foods are associated with decreased risk of bladder cancer. Furthermore, low serum levels of retinol and associated components were not found in patients with early transitional cell carcinoma. The finding of low serum levels of retinol, RBP and carotenoids in 4 patients with poorly differentiated invasive bladder tumours warrants further study.