Neoadjuvant versus adjuvant chemotherapy in cardiac tumor resection: A propensity-matched analysis of perioperative and long-term outcomes.

11555 Background: Optimal timing of systemic therapy for primary cardiac malignancies is undefined. We compared outcomes after surgical resection when chemotherapy was administered Neoadjuvant (≤4 months before surgery) compared to Adjuvant (≤4 months after). Methods: We conducted a retrospective cohort study using the TriNetX database of patients undergoing cardiac tumor resection who received chemotherapy either Neoadjuvant (≤4 months before surgery) or Adjuvant (≤4 months after). Patients were matched 1:1 using propensity scores based on demographics, comorbidities, and treatment variables, yielding 220 patients per group. Primary outcomes were all-cause mortality, infection, and transfusion within 30 days of surgery. Secondary outcomes included tumor recurrence at 1 year (90–365 days), all-cause mortality, and new-onset heart failure during 1–3 years of follow-up. Time-to-event analyses were performed using Kaplan–Meier methods with log-rank testing and hazard ratios (HRs); absolute and relative risks are reported as risk differences (RD) and risk ratios (RR). Results: After 1:1 propensity-score matching, 220 patients were included in each group. In the perioperative period (1–30 days), all-cause mortality occurred in 18/217 patients (8.3%) in the Neoadjuvant chemotherapy group compared with 30/213 (14.1%) in the Adjuvant group (RD −0.058, 95% CI −0.117 to 0.002; p=0.057), with a corresponding HR of 0.57 (95% CI 0.32–1.02; p=0.056). Infectious complications were lower with Neoadjuvant chemotherapy (12/220, 5.5%) than with Adjuvant chemotherapy (21/220, 9.5%) (RD −0.041, 95% CI −0.090 to 0.008; p=0.103; HR 0.54, 95% CI 0.27–1.10; p=0.090), while transfusion requirements were similar between groups (14.1% vs 12.3%; p=0.57). At 1 year (90–365 days), malignant cardiac tumor recurrence occurred in 27.7% of Neoadjuvant patients versus 21.4% of Adjuvant patients (RD +0.064, 95% CI −0.017 to 0.144; p=0.12; HR 1.16, 95% CI 0.80–1.70). During longer-term follow-up (1–3 years), all-cause mortality was comparable between groups (44.7% vs 47.4%), with longer median survival observed in the Neoadjuvant group (791 vs 516 days; HR 0.81, 95% CI 0.62–1.07; p=0.14). New-onset heart failure occurred at similar rates in both groups (p=0.98). Conclusions: In this cohort study of cardiac tumor resections, Neoadjuvant chemotherapy showed lower 30-day mortality and infection than Adjuvant chemotherapy, without significant differences in transfusion, 1-year recurrence, long-term mortality, or new-onset HF. These hypothesis generating findings suggest neoadjuvant chemotherapy is not associated with worse early or late outcomes and warrant confirmation in prospective, multi-center studies with histology-specific stratification and standardized systemic regimens.