Serum concentrations of retinol, β-carotene and zinc in women with breast cancer submitted to radiotherapy according to prior treatment modality and toxicity

Objective

To analyze serum concentrations of retinol, β-carotene and zinc in women with breast cancer undergoing radiotherapy, considering different modalities of previous treatment and toxic effects.

Methods

longitudinal study in a cohort of women with breast cancer assessed in pre-treatment (T0), 7 (T2) and 120 (T3) days after radiation therapy. Patients were divided into 3 groups, according to treatment modality prior radiation: breast-conserving surgery (G1), chemotherapy (G2) and breast-conserving surgery and chemotherapy (G3). Serum concentrations of retinol, β-carotene and zinc was assessed. Presence and degree of toxicity were assessed according to the scale of the RTOG for and RTOG/EORTC for acute and late toxicity, respectively.

Results

230 patients were assessed, mean age of 63.6 (±9.3) years. There was significant reduction in the mean of all micronutrients studied when comparing T0 to T1. At T2, all nutrients increased when compared to T1. For acute toxicity, there was no difference in antioxidant levels according to the degree of toxicity for any of the groups, with the exception of G3, which presented lower serum zinc concentrations in women with a higher degree of acute toxicity. In late toxicity, G1 had lower serum concentrations of retinol and B-carotene, when compared to G2 and G3.

Conclusion

The significant reduction of all micronutrients after radiotherapy, regardless of the type of the previous treatment, reinforces the oxidative impact of radiation and draws attention to the importance of maintaining an adequate nutritional status of antioxidants to improve the prognosis.