Session Item

Finding early predictors of late cardiotoxicity after a thoracic RT, which represents a significant risk factor for premature death, is warranted. This study aims to assess the effect of thoracic carbon ion radiotherapy (CIRT) on serum levels of C-reactive protein (CRP), troponin-I (TnI) and NT-ProBNP.

Clinical, laboratoristic and dosimetric data from 15 consecutive pts (median age: 67 years, range: 38-79, 53% female) treated with pencil beam CIRT (median total dose 56 Gy [RBE], range: 40-70 Gy [RBE]) for a para/intra-cardiac tumour at a single center were retrospectively reviewed. Most patients (10, 67%) were treated for thoracic localization of sarcomas (leiomyosarcomas N=3, chondrosarcomas N=2, liposarcomas N=2, hemangioendothelioma N=1, fibromyxoid sarcoma N=1, pleomorphic sarcoma N=1), 2 for adenoid cystic carcinomas, the rest for thyroid carcinoma (N=1), renal clear cell carcinomas (N=1) and colon adenocarcinoma (N=1). Laboratoristic parameters were collected before, during, at the end of CIRT and at 3, 6 and 12 months of follow-up (m-FU). Wilcoxon signed-rank test was applied to evaluate changes during treatment (baseline to CIRT-end) and after treatment (CIRT-end to 6m-FU). Any relationship between dosimetric/clinical data and laboratoristic changes over time was explored using Spearman correlation test and point biserial correlation index when appropriate. The significance level was set to 0.05.

Median FU was 6 months (range: 0 to 12 months). At baseline, diabetes (p= 0,035) and hypercholesterolemia (p=0,023) were associated with higher CRP value; hypercholesterolemia (p=0,045) with higher TnI values; tyroid disease (p<0.001) with higher NT-ProBNP values. Cardiovascular comorbidities, disease history, age and gender did not influence laboratoristic changes during and after CIRT. TnI and CRP values, both within the normal range, were unchanged, while NT-ProBNP values reported a significant increase during CIRT (from 56.3 to 100 pg/mL, p=0.045) and a trend towards decrease after (from 100 to 64 pg/mL, p=0.064). NT-ProBNP reduction related with the minimum dose (Dmin) to Left atrium (p=0.013, r=0.69), the maximum dose (Dmax) to left main coronary artery (p=0.012, r=0.7) and the Dmax to circumflex artery (p=0.01, r=0.71). There were no strong nor moderate significant correlations between NT-ProBNP variations and other dosimetric parameters on different cardiac structures.

CIRT did not affect the levels of CRP and TnI during and within 6 months after treatment for para and intra-cardiac tumours, while a significant change in NT-proBNP (increase and then reduction) was observed. After the initial increase, the reduction rate of NT-ProBNP was positively associated with some dosimetric parameters. Whether these biomarker changes increase the risk of long-term cardiovascular morbidity or mortality, will be addressed in the follow-up of our patients and with a larger prospective series.