The role of deep hyperthermia in IMRT in elderly patients with esophageal cancer: a retrospective cohort study.

Purpose: This study aimed to assess the clinical utility of deep hyperthermia in elderly patients with esophageal cancer(EC) who underwent intensity-modulated radiotherapy(IMRT).

Patients and methods: This retrospective analysis included 177 elderly patients with EC who underwent IMRT between 2017 and 2023, 42 of whom had combined deep hyperthermia (HT). Propensity score matching (PSM) was used to balance the covariates between the thermoradiotherapy (HTRT) group and IMRT-alone groups. Treatment outcomes and toxicities were compared between the two groups. We used the Kaplan-Meier method to estimate survival curves and the log-rank test to compare survival curves. Cox multivariate analysis was performed to analyze the prognostic factors in these patients.

Results: After PSM (42 patients in each group), the HTRT group had a greater objective response rate (ORR) than the IMRT-alone group (83% vs. 62%, P = 0.028). The HTRT group had less radiotherapy-related toxicity, including a lower incidence of leukopenia (14% vs. 33%, P = 0.040) and RP grade ≥ 2 (P = 0.012). However, the 1-, 2-, and 3-year overall survival (OS) rates and 1-, 2-, and 3-year disease-free survival (DFS) rates were not significantly different (P = 0.730, 0.964). Grade ≥ 2 hypoproteinemia (odds ratio [OR] = 3.798, P = 0.004), radiotherapy dose ≤ 60 Gy (OR = 0.445, P = 0.006), and tumor location in the lower esophagus (OR = 0.387, P = 0.005) were adverse prognostic factors for OS. Hypoproteinemia grade ≥ 2 (OR = 3.676, P < 0.001) was also a crucial prognostic factor for DFS.

Conclusion: Adding deep hyperthermia to IMRT can improve the ORR in elderly patients with EC. In addition, it significantly reduces radiotherapy-related toxicity. Although this approach does not improve the long-term prognosis, it is still practical and has low toxicity, making it suitable for clinical use.