Safety and Efficacy of Unresectable Malignant Cardiac Tumors Treated with Concurrent Chemoradiation Therapy Using a...

This trial aimed to investigate the safety and efficacy of treating malignant cardiac tumors with hypofractionated radiation therapy and concurrent chemotherapy (hypo-CCRT) using a 1.5T MR-Linac.

Patients with both primary and secondary malignant cardiac tumors underwent split-course hypo-CCRT on a 1.5T MR-Linac, receiving 30 Gy/6 fractions initially, followed by a boost course of 20 to 30 Gy/4 to 6 fractions, totaling 50 to 60 Gy. Concurrent chemotherapy (docetaxel and nedaplatin) was administered weekly. The primary endpoint was local recurrence-free survival (LRFS). Secondary endpoints included objective response rate, progression-free survival (PFS), overall survival (OS), toxicity, and quality of life.

From October 2021 to October 2023, 7 patients were enrolled in the study and received split-course hypo-CCRT on the 1.5T MR-Linac. The median follow-up was 26 months (range, 8.3-36.3 months). The objective response rate was 85.7% (6/7). The 2-year LRFS rate was 71.4%, with the median LRFS not reached. The 2-year PFS rate was 38.1%, with a median PFS of 20.1 months (95% CI, 8.8-31.5 months). The 2-year OS rate was 71.4%, with the median OS yet to be determined. No patients experienced acute or late toxicity above grade 2. Three months posttreatment, the ejection fraction percentage increased from 63.43% ± 7.21% to 68.57% ± 4.28% (P = .02), and the internal diameter of the right ventricle decreased from 24.43 ± 2.99 to 18.86 ± 3.13 mm (P < .01). The European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 scores were significantly improved at 6 months posttreatment (P < .05).

Split-course hypo-CCRT on MR-Linac for malignant cardiac tumors was feasible, generally well-tolerated, and showed promising oncologic as well as patient-reported outcomes in this small prospective cohort. Further study is warranted for the long-term effects.