Influence of Antineoplastic Treatment on Bioelectrical Impedance Vector in Women with Malignant Breast Neoplasm

Abstract

Introduction: Chemotherapy appears to promote increased weight and fat percentage, which are in connection with the development of mammary carcinogenesis. Objective: To evaluate the influence of the anti-cancer treatment on body composition and bioelectrical impedance vectors in women with breast cancer. Method: Observational study, both before and after, held from March 2012 to June 2013 at the General Hospital of Fortaleza (Ceará, Brazil), with 30 women with breast tumors, assessed after diagnosis and before the anti-cancer treatment (M1), and after the anticancer treatment (M2). The study collected anthropometric data, body composition and resistance values (R) and reactance (Xc) for vector analysis of bioelectrical impedance (BIVA). Results: The percentage of body fat was above the recommended levels in both instances [M1 = 35.6% (4.9) and M2 = 35.3% (4.7)] and lean body mass values were, respectively, 64 3% (4.9) 64.6% (4.7), without significant differences. The reactance (p=0.001) and the phase angle (p=0.000) had become reduced in M2. The impedance vectors, when M1 and M2 were compared, showed no significant shift (p=0,053). However, when compared with the mean vector of a reference population, it presented a significant displacement before (T2=95,2; p=0,000) and after (T2=53,2; p=0,000) the antineoplastic treatment, indicating alterations in the electrical properties of the tissue, fluid retention and loss of cell mass. Conclusion: Body composition did not change after the anti-cancer treatment. Changes in impedance vectors were suggestive of changes in the electrical properties of tissue, indicating a poorer clinical prognosis.