Effects of Lycopene on the Insulin-Like Growth Factor (IGF) System in Premenopausal Breast Cancer Survivors and Women at High Familial Breast Cancer Risk

Abstract

Insulin-like growth factor-I (IGF-I) is an important growth factor associated with increased risk of premenopausal breast cancer. We conducted a randomized, placebo-controlled, double-blind, crossover trial to evaluate whether tomato-derived lycopene supplementation (30 mg/day for 2 mo) decreases serum levels of total IGF-I in premenopausal women with 1) a history of breast cancer ( n = 24) or 2) a high familial breast cancer risk ( n = 36). Also, IGF binding protein (IGFBP) increasing effects were evaluated. Lycopene supplementation did not significantly alter serum total IGF-I and other IGF system components in the 2 study populations combined. However, statistically significant discordant results were observed between the 2 study populations (i.e., P < 0.05 for total IGF-I, free IGF-I, and IGFBP-3). Total IGF-I and IGFBP-3 were increased in the breast cancer survivor population [total IGF-I = 7.0%, 95% confidence interval (CI) = –0.2 to 14.3%; IGFBP-3 = 3.3%, 95% CI = 0.7–6.0%), and free IGF-I was decreased in the family history population (–7.6%, 95% CI = –14.6 to –0.6%). This randomized controlled trial shows that 2 mo of lycopene supplementation has no effect on serum total IGF-I in the overall study population. However, lycopene effects were discordant between the 2 study populations showing beneficial effects in high-risk healthy women but not in breast cancer survivors.