Bioelectical impedance changes during chemotherapy for early breast cancer: The Cando-2 study


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Stephen Wootton1
1University of Southampton, Southampton, UK

Abstract

Background

Excess adiposity and/or lack of lean tissue may be important determinants of chemotherapy outcomes. Bioelectrical Impedance Analysis (BIA) appears readily accessible in clinical settings but changes in hydration during treatment may violate the core assumptions that predict body composition. The measured values of resistance, reactance and phase angle remain secure and may in themselves differentiate between patients in terms of their resilience or response to treatment. The aim of this study was to better characterise the changes in impedance measures in women with early breast cancer during six cycles of standard neo/adjuvant chemotherapy (CANDO-2).

Method

Female patients with stage 1-3 invasive breast cancer were recruited from the breast oncology clinic at University Hospital Southampton between September 2014 and September 2015 and received standard-of-care neo/adjuvant chemotherapy (6 x 3 weekly cycles FEC100-T100).  Segmental BIA (Seca mBCA515) was measured in 29 women prior to each cycle and after the 6th cycle; impedance measurements were expressed as standard deviation scores (SDS) against device-specific healthy reference population values.

Results

The mean SD scores for resistance at 50 kHz (R5), reactance at 50kHz (Xc50), impedance ratio (R200:R5) and phase angle (PhA) at baseline were all within one SD of the median for the reference population. With each cycle of chemotherapy the mean R50 Z score rose progressively, especially from cycle 4 when docetaxel was commenced (P<0.01) with a corresponding fall in IR reflecting an increase in ECW and oedema. Mean Xc50 and PhA SD scores fell markedly with successive cycles reflecting loss of cellular integrity (P<0.01) with more than half of the patients with SD values greater than -2SD by the end of treatment.

Conclusion

Impedance measures offer the opportunity to objectively characterise systemic changes in physiological and metabolic state during treatment and may mark important differences between patients in their resilience to chemotherapy.