IORT

IORT, or intraoperative radiation therapy, is a cancer treatment that delivers a concentrated dose of radiation to the tumor bed during surgery, immediately after tumor removal and prior to wound closure. The aim is to treat areas at highest risk for residual microscopic disease while minimizing radiation exposure to surrounding healthy tissues.

There are two main delivery methods. Intraoperative electron radiation therapy (IOERT) uses an electron beam produced by a linear accelerator and delivered through a shielded applicator placed in the surgical field. Low-energy X-ray IORT delivers radiation from a compact, intraoperative X-ray source positioned directly in the operative site. Both approaches provide targeted irradiation in a single session and are planned in the operating room with collaboration among surgeons, radiation oncologists, and medical physicists.

Equipment and logistics involve a dedicated operating room or shielded suite, real-time imaging or contouring when possible, and precisely sized applicators or probes to tailor the field to the tumor bed. After completion, the surgical team continues with wound closure, and patients may receive additional external beam radiotherapy as part of a broader treatment plan.

Indications include selected cases of breast cancer (as a tumor-bed boost or partial breast irradiation), colorectal cancer, pancreatic cancer, gynecologic cancers, and certain sarcomas or head and neck cancers. IORT is often used in combination with external beam radiotherapy or chemotherapy, depending on the tumor type and patient factors.

Advantages include the delivery of a high single-fraction dose in a single session, potential sparing of surrounding organs, and shortened overall treatment time. Limitations involve the need for specialized facilities and expertise, potential surgical or wound-healing complications, and variable long-term evidence across tumor indications. Patient selection and multidisciplinary planning are essential.