Intraoperative Radiotherapy (IORT) is a form of breast cancer treatment in which the whole radiation therapy treatment is given during surgery after the tumour has been removed. It’s only available at one centre in Africa under Professor Justus Apffelstaedt of the University of Stellenbosch.
What is IORT?
IORT is a type of Partial Breast Irradiation and is based on the premise that, since 90 % of early breast cancer recurrences occur at the site of the original tumour, it makes sense to limit therapy to that spot.
“In IORT the radiation is given ‘from the inside out’,” explains Apffelstaedt, “an applicator is introduced in to the tumour bed and a radioactive source is then inserted in to the centre of the applicator to administer a large dosage of radiation, which is given in one go.”
This is different to the more traditional external beam radiation which is given for five to seven weeks in daily administrations by an external radiation machine.
Who should receive IORT?
Patients are selected by a combined clinic consisting of a breast surgeon, a medical oncologist and a radiation oncologist. Only certain tumours qualify. Among other criteria:
· The tumour must not be larger than 3cm
· No more than three lymph nodes can be involved
· The patient must be 50 years old or older. In young patients the entire breast tissue is thought to be unstable and leaving parts of the breast untreated is likely lead to tumour recurrence.
Christine Mouton’s breast cancer was discovered during a routine mammogram, she was a candidate for IORT and admitted she is still ‘happy and thankful’ that she chose this treatment, which she highly recommends to other women.
“I was upset when I was diagnosed, but in a strange way also thankful that the lump was so small and that it was caught early. A biopsy was done to confirm the initial diagnosis. It was surgically removed three weeks later and radiation was done during the operation,” she said.
Mouton explained that after she was diagnosed, she met with a panel which consisted of a surgeon, an oncologist and a plastic surgeon who discussed the treatment with her. They explained the procedure in detail and answered all her questions.
“The alternative treatment of five to six weeks of daily radiation would have disrupted my life a lot more and would have caused a lot more discomfort than a once-off radiation. The treatment was explained very professionally to me as a ‘lay’ person. At no point did I doubt the doctors' credibility even if the type of treatment was completely new to me,” said Mouton.
After the operation Mouton admitted she felt some discomfort, but to her surprise, picked up her life where it left off almost immediately.
“I went walking with my dogs and after three weeks I took up my Pilates classes again. This was much better than what impact I know breast cancer and its treatment can have on a women's life.”
Yet while she recommends this type of treatment to other women who are considering it, given her positive experience, she humbly said, “It is difficult for me to give advice to women who already have breast cancer – just stay positive and to grab onto life with both hands afterwards.
“I didn't experience all the trauma of mastectomies, radiation and chemo and have therefore not walked such a difficult path.
What procedures are used during IORT?
Several different IORT methods have been used in the past, each using a different applicator and source of the radiation.
In the TARGIT trial, the applicator is made of acrylic material and the radiation source is a 50 KiloElektronVolt x-ray tube. This radiation is soft and can be given in an ordinary theatre with minimal shielding.
Another method of IORT can be done with the MAMMOSITE® Radiation Therapy System which received FDA clearance in 2002. The applicator here is an inflatable balloon; the radiation source a radioactive Iridium192 seed. Radiation is hard (622 KiloElektronVolt) and therefore the radiation can only be given in a radiation bunker.
The MAMASPHERE is similar to TARGIT, but uses a medical grade nylon applicator and a radioactive Iridium192 seed. Again, the radiation must be given in a radiation bunker.
Still another method (ELIOT) is used by the European School of Oncology in Milan: Perspex applicators are used and the radiation source is a linear accelerator delivering very hard radiation (MegaElektronVolt), requiring very thick lead shielding of the operating room.
Advantages of IORT
Compared to postoperative external beam radiotherapy, IORT has the following advantages:
- IORT spares normal tissues of breast, heart and lungs, as the radiation dosage falls off rapidly with increasing distance from the tumour bed: typically there is no radiation effect 2cm from the targeted area.
- Radiation is applied directly to the tumour bed, the area where it is needed most.
- The spherical applicator distributes the dose evenly to all parts of the tumour bed.
- There is no delay between surgery and the irradiation of any remaining cancer cells.
- The spherical IORT applicator fits right into the space left by the tumour removal, while external beam radiotherapy is delivered from outside the body and therefore has to travel through tissue not at risk of malignancy and does collateral damage there.
- Radiation is completed in one intraoperative session: the patient awakes and all local therapy is completed.
- The schedules of women are not interrupted for five to seven weeks of radiation sessions.
- Radiotherapy departments will save costs and reduce waiting times for all other cancer patients.
- Patients who are unable to attend postoperative radiotherapy sessions will be able to undergo breast conserving therapy.
What have been the results of IORT to date?
According to Apffelstaedt, early, small series of single institutions have reported comparable cancer control rates over 10 years as conventional radiation therapy.
“More reports of very large multi-centre studies are appearing that confirm these results in medium-term (five years) follow-up and confirm, that this method is safe.”
Sources: Christine Mouton; Professor Justus Apffelstaedt: Associate Professor, University of Stellenbosch and Head of the Breast Clinic: Tygerberg Hospital.