Tuesday 28th April 2015
Mac Voice, the magazine for Macmillan professionals: Spring 2015
Sarah James and Elizabeth Halliday describe this emerging form of radiotherapy, which takes place immediately after surgery
Radiotherapy is most commonly given using linear accelerators. These are sophisticated machines, designed to deliver high-energy x-rays and electron beams. The beams are directed to the outside of the body, hence the term external beam radiotherapy.
Most radiotherapy is delivered on an outpatient basis. Every person treated has a tailored combination of radiation beams. This ensures the tumour, and a margin of tissue around it, is exposed to the required dose of radiation, while the dose to nearby normal tissues is minimised.
This is the principal aim of all radiotherapy, as exposing normal tissues to radiation can cause side effects.
What is intraoperative radiotherapy?
Intraoperative radiotherapy (IORT), as the name implies, is a technique delivering radiotherapy during surgery. It directs low-energy x-rays to the area of the body requiring exposure to radiation.
This is done while the person remains under anaesthetic in the operating theatre, and immediately after their tumour has been removed.Using this technique means that the radiation beam does not travel through other parts of the body to treat the desired area.
Another benefit is that there is no delay between the surgery and delivery of radiotherapy, so it only involves one visit for the person being treated.
Decisions about intraoperative radiotherapy
IORT can only be delivered by highly trained staff, using specially-designed equipment. The decision to use this type of radiotherapy should be a multidisciplinary one, in the same way that all people with cancer have their clinical case discussed and a management plan decided.
Giving IORT increases the length of the surgery by about 40 minutes, depending on the size of the applicator.
The National Institute for Health and Care Excellence (NICE) advises that all people with breast cancer who have breast-conserving surgery should also receive radiotherapy, to reduce the risk of their cancer reoccurring.
The gold standard radiotherapy for this is currently external beam radiotherapy.
However, there has been research in recent years into using external beam radiotherapy to treat only part of the breast – so-called partial breast irradiation. IORT is one form of partial breast irradiation and can be used to treat just the tumour site.
The TARGIT-A trial was an international, randomised, controlled trial, which aimed to establish the non-inferiority of giving IORT using Intrabeam equipment (a particular brand) compared to irradiating the entire breast using external beam radiotherapy.
This trial was not suitable for all people requiring radiotherapy for breast cancer, but was suitable for those with small, low-grade tumours. Six treatment centres in the UK participated.
While the trial has finished recruiting patients, a longer follow up time is required for the trial question to be fully answered.
Some people may receive IORT out of the trial setting, for a variety of reasons; for example, where they are at greater risk of side effects from external beam radiotherapy or if they have certain comorbidities. NICE are currently appraising IORT using Intrabeam, and assessing the evidence and benefits to people with cancer.
The outcomes of this appraisal will determine who should be offered IORT as the preferred treatment.
Email Sarah James (pictured above right), Professional Officer, Society and College of Radiographers, Macmillan Patient Information Lead, Lynda Jackson Macmillan Centre
Email Elizabeth Halliday (pictured above left) Superintendent Radiographer / IORT Pathway Coordinator, Royal Free London NHS Foundation Trust.