Epidemiological and laboratory studies suggest that vitamin supplement
s may be helpful in the prevention of some cancers but clinical trials
to date have failed to demonstrate protection with naturally occurrin
g vitamins. Without substantiation of the highly touted benefits of vi
tamins, few physicians who care for cancer patients have recommended t
heir use. A total of 65 patients with biopsy confirmed transitional ce
ll carcinoma of the bladder enrolled in a randomized comparison of int
ravesical bacillus Calmette-Guerin (BCG) with or without percutaneous
administration was also randomized by closed envelope to therapy with
multiple vitamins in the recommended daily allowance (RDA) versus RDA
multivitamins plus 40,000 units vitamin A, 100 mg. vitamin B6, 2,000 m
g. vitamin C, 400 units vitamin E and 90 mg. zinc. The addition of per
cutaneous BCG did not significantly lessen tumor recurrence but recurr
ence after 10 months was markedly reduced in patients receiving megado
se vitamins. The 5-year estimates of tumor recurrence are 91% in the R
DA arm and 41% in the megadose arm (p = 0.0014, Mantel-Cox). Overall r
ecurrence was 24 of 30 patients (80%) in the RDA arm and 14 of 35 (40%
) in the high dose arm (p = 0.0011, 2-tailed Fisher's exact test). Meg
adose vitamins A, B6, C and E plus zinc decrease bladder tumor recurre
nce in patients receiving BCG immunotherapy. Further research will be
required to identify which ingredient(s) provide this protection.