P0118 Early cardiac changes due to doxorubicin-based chemotherapy and radiotherapy in early stage and locally advanced breast carcinoma patients: A descriptive study

Abstract

Background The aim of this study was to determine early cardiac changes from doxorubicin-based chemotherapy and radiotherapy in patients with early and locally advanced carcinoma of the breast and to assess cardiac changes in relation to radiation dose received by heart. Methods In this a single centre descriptive study, 56 patients with either early or locally advanced breast cancer were analysed. ECG, ECHO, and ERV were done at baseline, after chemotherapy, after radiotherapy, and after 6 months of follow up. Changes in ECG, ECHO, and ERV were recorded at different time periods during the study. Left ventricular ejection fraction (LVEF) was recorded using both ECHO and ERV. Patients were divided into four groups. Group 1 patients completed all six cycles of chemotherapy before starting radiation. Group 2 patients received all six cycles of chemotherapy after completion of radiotherapy. In group 3 patients underwent neoadjuvant chemotherapy followed by mastectomy. In these patients radiotherapy was completed before adjuvant chemotherapy. Group 4 patients received only six cycles of chemotherapy. Findings The most common ECG change was T wave inversion in the pre-cordial leads. One patient had ST depression in V4 and V5 leads and two had physiological T wave inversion in lead III. In group 1, mean LVEF (ECHO) at baseline was 66.79 ± 3.73. It decreased to 63.45 ± 3.54 after chemotherapy. It further decreased to 61.64 ± 4.26 after radiotherapy. On follow up there was a further decline to 61.42 ± 3.27. In group 2, baseline mean LVEF was 66.67 ± 4.33. Post radiotherapy, it slightly decreased to 66 ± 4.975, while post chemotherapy it further declined to 62.7 ± 2.92. During follow up mean LVEF further decreased to 61.89 ± 2.934. In group 4, baseline mean LVEF was 67.25 ± 4.33, which decreased after chemotherapy to 64.75 ± 2.062. During follow up it further decreased to 63.25 ± 2.363. LVEF was also measured by MUGA/ERV. In group 1 mean LVEF at baseline was 58.14 ± 2.997. After chemotherapy it decreased to 56.15 ± 3.144. After radiotherapy it increased to 56.21 ± 3.81 and during follow up mean LVEF decreased to 55.21 ± 2.913. In group 2 mean LVEF at baseline was 59.11 ± 1.41 which decreased to 58.67 ± 2.872 after radiotherapy and post chemotherapy it decreased to 54.44 ± 1.81. During follow up it increased to 55.22 ± 1.787. In group 4 mean LVEF at baseline was 60 ± 1.63, which decreased to 58.75 ± 1.89 after chemotherapy. During follow up it further decreased to 56.25 ± 2.63. Interpretation Our prospective study shows that a significant number of patients can develop a transient depression in ventricular function after chemotherapy and radiotherapy. ECG changes in our study were not specific. T wave inversion was the most common abnormality, suggestive of ventricular repolarisation abnormality. Decrease in LVEF was seen in our patients both by conventional ECHO and MUGA/ERV scan during different phases of treatment. These changes indicate that doxorubicin-based chemotherapy and radiotherapy produce acute abnormalities in left ventricular function. Whether these results are predictive of the development of chronic cardiac toxicity can only be answered by serially investigating these patients for a longer duration.