Intraoperative Radiotherapy (IORT)

IORT is a form of radiotherapy delivered in the operating room rather than over many separate hospital visits. In conventional treatment, radiation is usually given in small daily fractions for several weeks once the surgical wound has healed. With IORT, the radiation is delivered in a single concentrated dose during the same operation, at the moment the surgeon has just removed the tumour and the area is fully exposed. Different systems are used to produce the radiation, including mobile units that generate low-energy photons or electrons placed at the patient's side. Because the dose is applied straight to the tumour bed under direct vision, it can be focused tightly on the tissue at risk while the surgeon protects the surrounding structures.

After the surgeon removes the tumour, the radiation oncology team reviews the exposed tumour bed and selects an applicator that fits the cavity or surface to be treated. The applicator is positioned precisely on the target area, and skin, muscle and nearby organs are shielded or moved aside so they receive as little radiation as possible. The single planned dose is then delivered over a short period, often a matter of minutes, while the patient remains under the same anaesthesia. Throughout, the surgical and radiation teams stay with the patient and the operating room is set up to deliver the dose safely. Once treatment is complete, the applicator is removed and the surgeon finishes closing the wound in the usual way, so the whole step is built into the operation.

IORT is most established in early-stage breast cancer, where, for carefully selected patients, a single dose delivered to the area around where the tumour sat can replace or substantially shorten the weeks of external radiotherapy normally given after breast-conserving surgery. It is also used in selected other situations, including certain abdominal, pelvic and recurrent tumours, where delivering radiation directly to a hard-to-reach or previously treated area during surgery can be valuable. Suitability is never automatic: the surgical and radiation oncology team decides on a case-by-case basis, looking at the tumour type, its size, the pathology findings and the individual's overall plan of care. It is one option among several, chosen only when it fits the patient and the disease.

The main advantages of IORT are precision and convenience. Because the dose is placed directly on the tissue at risk under direct view, it concentrates radiation where it is most needed and helps spare the skin and nearby organs, which can mean fewer skin and tissue side effects than a long course of external radiotherapy. For suitable patients it can also remove the need for, or greatly reduce, several weeks of daily radiotherapy visits after the operation, which is a meaningful benefit for people who have travelled for treatment. The treatment is given during the operation, so you do not feel it and there is no separate appointment for it. Your care team explains beforehand whether IORT alone is enough or whether some additional radiotherapy may still be advised based on the final pathology.