3072 - A Prospective Pilot Study of Cardiac MRI (cMRI) for Evaluation of Early Cardiac Toxicity in Patients Receiving Neoadjuvant Chemoradiotherapy (nCRT) for Esophageal Cancer

M. Shuja¹, A. B. Challa², W. S. Harmsen³, J. D. Collins², P. M. Young², A. Bratt², W. Breen¹, R. O. Kowalchuk¹, M. G. Haddock¹, K. W. Merrell¹, K. R. Jethwa¹, C. M. Callaghan¹, and C. L. Hallemeier¹; ¹Department of Radiation Oncology, Mayo Clinic, Rochester, MN, ²Department of Radiology, Mayo Clinic, Rochester, MN, ³Department of Biostatistics and Health Sciences Research, Mayo Clinic, Rochester, MN

Purpose/Objective(s): Neoadjuvant chemoradiation (nCRT) for esophageal cancer can result in significant radiation exposure to the heart. Acute symptomatic cardiac toxicity during nCRT is rare; however, delayed cardiac effects are a major concern. Early biomarkers predictive of delayed cardiac toxicity would be of great utility. We hypothesized that cMRI would identify early structural and functional changes in patients receiving nCRT for esophageal cancer. Materials/

Methods: Patients with esophageal cancer receiving nCRT prior to planned esophagectomy were enrolled. Patients underwent cMRI without and with gadolinium at baseline and 4-8 weeks after nCRT, but before esophagectomy. Baseline mean cardiac dose, cardiac functional parameters for left (LV) and right ventricle (RV), including end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), cardiac output (CO), myocardial mass, and global strain metrics in short-axis (SAX) and long-axis (LAX) were evaluated pre- and post-treatment using Wilcoxon signed rank test.
Results: Thirty-one patients were enrolled and completed the baseline and post-nCRT cMRI. Median age was 64 years (48-81 yrs) and 87% were male. Tumor location was distal esophagus in 84% and histology was adenocarcinoma in 84%. T-stage was T3 in 84% and nodal involvement was seen in 80% of patients. Median RT prescription dose was 50 Gy in 25 fractions (71%) with interquartile range of 41.4 (16%) to 50.4 Gy (13%). RT modality was proton in 61% and photon in 39%. Median heart mean dose was 7.4 Gy and median V40Gy was 7%. Posttreatment changes in LV EDV, LV SV, LV EF, RV EDV, RV ESV, SAX peak global strain were statistically significant (p=<0.05).
Conclusion: In patients with esophageal cancer receiving nCRT, early structural and functional cardiac changes were identified on cMRI 4-8 weeks after treatment. Larger prospective studies are needed to confirm these findings and to examine for correlation with clinical outcomes.

Abstract 3072 – Table 1

Characteristic	Baseline (mean)	Post-nCRT (mean)	p-value
LV EDV (mL)	124	112	0.0007
LV ESV (mL)	62	60	0.28
LV SV (mL)	62	54	0.014
LV EF (%)	51	49	0.029
LV CO (L/min)	4.09	3.6	0.066
RV EDV (mL)	144	129	0.0007
RV ESV (mL)	85	75	0.007
RV SV (mL)	59	55	0.27
RV EF (%)	41	40	0.98
RV CO (L/min)	3.9	3.7	0.44
Diastolic myocyte mass (g)	108	102	0.10
Systolic myocyte mass (g)	108	105	0.10
SAX peak global circumferential strain (%)	-16	-14	0.0009
SAX peak global radial strain (%)	25	22	0.0016
LAX peak global circumferential strain (%)	-14	-14	0.58
LAX peak global radial strain (%)	24	22	0.28