Intraoperative radiotherapy during breast cancer surgery: acute and chronic cardiac safety tested by an ultra-sensitive troponin and N-terminal Pro-B-type natriuretic peptide

Aim: Intraoperative radiotherapy (IORT) is now an acceptable option for low risk early stage breast cancers, allowing patients not to undergo a full course of external radiotherapy. It is not clear, however, whether IORT, providing radiations very close to the chest wall, may produce heart damage. In this study we tried to evaluate if acute or chronic heart damage in early stage breast cancer patients treated with breast conservative surgery (BCS) and IORT, can be assessed by ultra-sensitive cardiac Troponine I (TnI) levels or N-terminal proB-type natriuretic peptide (NT-proBNP), respectively. Materials and methods: We enrolled 43 patients who received IORT for breast cancer, as part of a TARGIT-A trial. Twenty-two patients had left and 21 right breast cancer. TnI levels were measured immediately before surgery, and six hours after the end of IORT; both TnI and NT-proBNP levels were measured after 12 months. For the patients with left breast cancer, a little tungsten sheet was placed under the major pectoralis muscle, on the chest projection of the X-ray source, in order to protect the heart. Results: None of the patients showed altered serum levels of TnI before surgery, or after IORT procedure and NT-proBNP during follow-up. No difference in TnI and NTproBNP values was noticed between right-sided and left-sided breast cancers treated with BCS and IORT. Conclusions: IORT for early stage breast cancer treatment does not increase TnI and NT-proBNP levels, suggesting that the procedure does not determine acute or chronic heart damage.