Cardiac serum marker alterations after intraoperative radiotherapy with low-energy x-rays in early breast cancer as an indicator of possible cardiac toxicity

Stefan Stefanovic,Sebastian Berlit,Frederik Trinkmann,Elena Sperk,Marc Sütterlin,Christel Weiß,Benjamin Tuschy,Frederik Wenz

doi:10.1007/s00066-020-01671-3

Abstract

PurposeTo assess acute cardiac toxicity caused by intraoperative radiotherapy (IORT) with low-energy x‑rays for early breast cancer.MethodsWe prospectively analyzed pre- and postoperative troponin I and NT-proBNP in 94 women who underwent breast-conserving surgery between 2013 and 2017 at the Department of Gynecology and Obstetrics of the University Medical Center Mannheim, Germany. Thirty-nine women received IORT using low-energy x‑rays during breast-conserving surgery while 55 patients without IORT formed the control group. Demographic and surgical parameters as well as cardiac markers were evaluated.ResultsThere were no significant differences concerning age and side of breast cancer between the groups. Furthermore, no significant difference between the troponin I assays of the IORT and control groups could be found (preoperatively: 0.017 ± 0.006 ng/ml vs. 0.018 ± 0.008 ng/ml; p = 0.5105; postoperatively: 0.019 ± 0.012 ng/ml vs. 0.018 ± 0.010 ng/ml; p = 0.6225). N‑terminal fragment of B‑type natriuretic peptide (NT-proBNP) was significantly higher in the control group 24 h after surgery (preoperatively: 158.154 ± 169.427 pg/ml vs. 162.109 ± 147.343 pg/ml; p = 0.56; postoperatively: 168.846 ± 160.227 pg/ml vs. 232.527 ± 188.957 pg/ml; p = 0.0279).ConclusionTroponin I levels as a marker of acute cardiac toxicity did not show any significant differences in patients who received IORT during breast-conserving surgery compared to those who did not.

Highlights

With a lifetime risk of almost 10%, breast cancer is the most common malignant tumor in the female population worldwide
Breast cancer treatment in the majority of cases consists of breast-conserving surgery (BCS), which is typically combined with axillary sentinel lymph node biopsy (SNB) followed by external beam whole-breast radiotherapy (EBRT)
Nonsignificant differences were observed in the frequency of antecedent cardiovascular disease barring arterial hypertension (10 patients in the non-intraoperative radiotherapy (IORT) vs. 1 in the IORT group; p = 0.075)

Summary

Introduction

With a lifetime risk of almost 10%, breast cancer is the most common malignant tumor in the female population worldwide. Other crucial therapeutic principles in the treatment of breast cancer are chemotherapy, endocrine, and targeted therapies. Strahlenther Onkol (2021) 197:39–47 tumor bed boost application lies in the potential risk of missing the target, which is considered to be 20–90% [1]. This risk of missing the tumor bed can be reduced by the application of intraoperative radiotherapy (IORT) to the tumor bed during BCS immediately after removal of the tumor [2]. Besides minimizing the risk of “geographical miss,” IORT can shorten the interval between tumor excision and the beginning of adjuvant radiotherapy, thereby making a “temporal miss” unlikely as well [2]

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