Intraoperative Electron Beam Radiation Therapy (IOERT) Versus High-Dose-Rate Intraoperative Brachytherapy (HDR-IORT)...

Area of Science:

• Oncology
• Radiation Oncology
• Surgical Oncology

Background:

• Intraoperative radiation therapy (IORT) encompasses intraoperative electron beam radiation therapy (IOERT) and high-dose-rate intraoperative brachytherapy (HDR-IORT).
• IORT is utilized to potentially decrease local recurrence rates in patients diagnosed with locally advanced rectal cancer (LARC) and locally recurrent rectal cancer (LRRC).

Purpose of the Study:

• To compare the oncological outcomes between IOERT and HDR-IORT.
• To evaluate the efficacy of IORT modalities in patients with LARC or LRRC who have undergone a microscopic irradical (R1) resection.

Main Methods:

• A retrospective analysis included consecutive patients who received IORT for R1 resection of LARC or LRRC between 2000 and 2016.
• R1 resection was defined as a resection margin of ≤2 mm for LARC and 0 mm for LRRC.
• Oncological outcomes and postoperative complications were compared between IOERT and HDR-IORT groups.

Main Results:

• Overall survival did not significantly differ between IOERT and HDR-IORT.
• HDR-IORT demonstrated significantly longer local recurrence-free survival in both LARC (HR, 0.496) and LRRC (HR, 0.567) cohorts.
• Major postoperative complications were similar in LARC patients but higher in LRRC patients treated with HDR-IORT compared to IOERT.

Conclusions:

• HDR-IORT offers superior local recurrence-free survival for patients with R1 resections in LARC and LRRC.
• Further optimization of the IOERT technique may be necessary to improve its effectiveness.
• The choice of IORT modality should consider the specific cancer type and patient characteristics.