Single-dose intraoperative radiotherapy (SD-IORT) for early stage breast cancer

Spire Bristol Hospital's breast specialist consultant Mr Simon Cawthorn has introduced a new innovative treatment for early stages of breast cancer. Intraoperative radiotherapy (IORT) of the breast is a type of breast radiation administered by the breast surgeon as a single treatment during surgery. It is performed immediately after surgery to remove the lump, when the patient is still under anaesthesia.

SD-IORT is considered an effective and safe alternative to standard breast radiotherapy, which is usually administered after a lumpectomy on a daily basis for up to five weeks. For many women, IORT makes breast conservation and breast radiotherapy a far more practical and convenient treatment option.

SD-IORT delivers radiation inside your breast close to where the tumour was. The goal of radiotherapy is to preserve the healthy tissue and eliminate any remaining cancer cells. Even though breast surgeons make every possible effort to remove all cancerous tissue at the time of surgery, microscopic cancer cells are often difficult to detect and to surgically remove. Large trials involving women with early breast cancer have clearly shown that only by delivering post lumpectomy radiotherapy to the breast can the risk of local occurrence become as low after a mastectomy.

With SD-IORT, your breast surgeon can deliver the appropriate dose of radiation to the tumour bed in a single dose. When you wake up from your surgery, the tumour has been removed and the area surrounding it has been irradiated. This often means that you don’t need additional radiation treatment, although the final decision will depend on your individual circumstances.

Spire Bristol Hospital are the first and only place in the South West to perform this new procedure. To date, Mr Cawthorn has performed 3 SD-IORT procedures, and is happy to see patients who might want to come to Bristol to see him if they are considering the surgery.

For patients considering the surgery, the tumours must be small (less than 2 cms) and low grade cancers which have not spread to the lymph nodes - ideally those detected through mammogram screening.

How does the SD-IORT treatment work?

In the operating theatre, your breast surgeon will place a specially designed inflatable balloon applicator into the space where the tumour was removed. This space is called the tumour bed. Your surgeon can change the size of the balloon by inflating or deflating it until it fits snugly into the tumour bed. After the cancer has been removed a steel plate is placed on the chest wall to prevent damage to the ribs, lungs and heart. The entire dose of radiation is delivered in as little as 10–20 minutes.

Which patients are well suited for SD-IORT?

If you are suitable for a lumpectomy procedure and are 45 years of age or older you might be eligible for SD-IORT. It will also depend on what stage your breast cancer is – this treatment is best suited for early stage breast cancer that is oestrogen-receptor positive. Other factors, such as the size of your tumour, are also important. SD-IORT with Xoft is suitable for tumours of 3 cm or less.

What is the proof that IORT is safe and effective for early stage breast cancer?

Brachytherapy has been used for decades to treat cancer in various parts of the body in many parts of the world including the UK, Europe and the USA. In the 1990s, several clinical trials were developed to investigate the use of IORT in patients undergoing lumpectomy of breast cancer.

The largest and most comprehensive of these clinical trials is the TARGIT trial which compared two groups of women who had breast conserving surgery for breast cancer:
• One group had targeted intraoperative radiotherapy (IORT) – a single dose of radiotherapy during surgery
• The other group had 3 to 5 weeks of daily whole breast radiotherapy after surgery

The aim was to find out if the women treated with IORT were more at risk of their breast cancer coming back.
Thinking behind the trial
Most breast cancers recur close to the site of the original tumour. Directing a single dose of radiotherapy to the area around the tumour, just after it had been removed, could be just as effective as 5 weeks of daily radiotherapy to the whole breast. Furthermore, the exposure of the normal body to the radiation is considerably reduced. Having a single dose of radiotherapy has many advantages over going to hospital every day for five weeks, but researchers wanted to make sure that single dose IORT did not put women at greater risk of their breast cancer recurring.
Women aged 45 or older with invasive ductal breast cancer who were treated with breast conserving surgery. Participants were recruited from 28 centres in 9 countries.

Results from the TARGIT trial
• A total of 996 women received IORT while 1025 had whole breast radiotherapy
• In the IORT group, some women were found to have additional problems such as lobular cancer, which meant they were also needed whole breast radiotherapy. This affected 142 of the women (14%)
• After 4 years, 5 women in the external radiotherapy group had their breast cancer come back and there were 6 recurrences in the IORT group. This difference was not significant.

The frequency of major adverse events and complications was similar in both groups but the IORT was better tolerated by the women than daily radiotherapy.

2012 TARGIT trial update
In 2012, up to 5 years of follow up researchers reported that 2% more of the women treated with IORT had a breast cancer recurrence compared to those treated with whole breast radiotherapy. However, the overall number of deaths in the IORT group after 5 years was lower than the whole breast RT group. This was because fewer women died from causes other than breast cancer in the IORT group. The reasons for the difference in death rates are not known and are being debated by clinicians at this time.

This large study of 3500 women demonstrated that single dose IORT is just as effective as whole breast radiotherapy. Single dose IORT can be used as an alternative to whole breast external radiotherapy in most women but some still need daily radiotherapy in addition. The first set of results from the TARGIT trial was published in the Lancet in June 2010.

What are the possible side effects of SD-IORT?

You usually experience fewer side eects after SD-IORT with Xoft compared to other types of breast radiation because less of the breast is being treated. Some patients suffer a mild tenderness or discomfort after they wake up from their
lumpectomy. Early side effects can include redness of the skin over the surgical site, dryness, and itching, which go away after a few weeks. Some women have bruising and swelling around the site. There will probably be a small amount of drainage from the area where your surgeon inserted the balloon. A small number of patients can have fluid
build-up, bleeding, infection or a delay in wound healing where the applicator was inserted.

Because the surgery and the radiation therapy can be done at the same time, many patients prefer SD-IORT. Many patients are comforted knowing that they don’t have to wait for their radiation treatment to begin at a later date. Many also appreciate being able to return to their usual living routines more quickly because of the simple convenience.

What are the benefits of having SD-IORT for breast cancer?

• Shorter treatment times: Because SD-IORT is a single targeted dose on one day, patients can usually return to normal life routines more easily. There isn’t the disruption to family and work life of travelling to and from the hospital daily for many weeks. In most cases, only one radiation treatment is necessary.
• Speed of treatment: In early stage breast cancer, SD-IORT delivers a concentrated dose of radiation to a tumour site immediately after the tumour is removed. This immediate treatment helps to destroy microscopic and undetectable cancer cells that may remain despite the surgeon’s best efforts to remove every last bit of cancer.
• Clinical research shows that the immediate tumour site is often at high risk of recurrence and traditional breast cancer radiation therapy requires a recovery period after lumpectomy surgery, which potentially leaves microscopic untreated disease in this area for some time.
• Spares healthy tissues: During breast SD-IORT, a very precise radiation dose is applied while protecting healthy tissue with an internal shield. Normal tissues and critical organs such as the heart, lungs and ribs can be spared from receiving radiation.

Advantages of SD-IORT with Xoft

Only one radiation treatment needed
• Less patient travel, fewer hospital appointments
• Fewer side effects
• Better cosmetic results
• Immediate reconstruction can be done right away
• Faster recovery time for patients

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