Breast cancer radiotherapy during surgery could ease treatment

Date: Nov-12-2013Two new studies published in leading journals this week show how a "one-stop" targeted

radiotherapy given during lumpectomy may offer some patients with early-stage breast cancer a

viable alternative to current treatments. Experts say the approach looks promising but more

research is needed to identify which patients are most likely to benefit.

Most women with breast cancer who undergo lumpectomy or partial mastectomy also undergo a course

of radiation delivered to the whole of the affected breast.

While such treatment - called external beam radiotherapy, EBRT - reduces the risk of cancer

coming back, it is not an easy undertaking and can cause unpleasant side effects. It takes weeks

and requires regular attendance at centers that are not always easy to get to.

Such a prospect is sometimes the reason some women have a full mastectomy.

Faced with this rather unsatisfactory state of affairs, researchers have been investigating

whether a single dose of radiation, given during or soon after surgery and specifically targeted at

the site of the tumor, might offer a workable alternative.

The two studies, one published in The Lancet and the other in The Lancet

Oncology, describe the results of two trials (TARGIT-A and ELIOT), each evaluating a different

way of delivering such targeted radiation.

The TARGIT-A trial

In the TARGIT-A trial, a large international team of researchers compared TARGIT with a standard

EBRT course. The TARGIT method used a miniature X-ray machine to deliver targeted radiation to the

tumor site once only during lumpectomy or about a month later, while the EBRT course comprised

daily doses of radiotherapy for between 3 and 6 weeks.

Over the 12 years of the trial, over 1,700 women underwent TARGIT, and another similar-sized

group underwent standard EBRT at over 30 centers.

Across both groups of women, the difference in the 5-year risk of the cancer returning in the

breast was under 2.5%, indicating that a single TARGIT treatment was no less effective than EBRT in

controlling cancer.

Also, the overall rate of death (number of patients who died within the 5-year period) was 3.9%

with TARGIT and 5.3% with EBRT, mainly because of significantly fewer deaths due to other cancers

and cardiovascular conditions.

When the researchers restricted their analysis to include only comparison of TARGIT given during

surgery against EBRT, the local recurrence of breast cancer and deaths due to breast cancer were

the same in both groups, but deaths from other causes were significantly lower in the TARGIT group

than the EBRT group (1.3% versus 4.4%, respectively).

One of the study leaders, Prof. Jayant Vaidya of University College London, UK, says the

most important benefit of TARGIT for women with breast cancer is they can have their complete

radiotherapy treatment at the same time as their lumpectomy, with lower toxicity to the breast, the

heart and other organs, adding that:

"Our research supports the use of TARGIT concurrent with lumpectomy, provided patients are

selected carefully, and should allow patients and their clinicians to make a more informed choice

about individualizing their treatment, saving time, money, breasts and lives."

The ELIOT trial

In The ELIOT trial, published in The Lancet Oncology, a group of researchers in Italy tested

a slightly different targeted radiotherapy. Unlike TARGIT where X-rays are used, ELIOT, which

stands for electron intraoperative radiotherapy, emits electron radiation to the tumor site.

The participants were just over 1,300 women attending the European Institute of Oncology in

Milan for early breast cancer treatment, half of whom received ELIOT during lumpectomy surgery, and

the other half, the controls, received standard EBRT after lumpectomy.

The results showed that cancer recurrence in the affected breast was significantly higher in the

ELIOT group than the controls. This was the case whether the researchers classed recurrence as

either to the tumor site or anywhere in the affected breast.

However, despite this, the overall survival at 5 years did not differ significantly between the

ELIOT and control group (34 deaths versus 31 deaths respectively). And there were no significant

differences in deaths due to breast cancer or to any other causes.

In this study, the researchers also analyzed the tumors of women whose cancer returned and found

tumor size (over 2 cm) and estrogen-receptor negative (ER-negative) were among the features most

likely to be linked to recurrence.

Study leader Prof. Umberto Veronesi, of the European Institute of Oncology in Milan,

says:

"For women who receive intraoperative radiotherapy, identifying the features most commonly

associated with recurrence of cancer in the breast that has been operated on will allow us to

identify the patients most likely to benefit from subsequent external radiotherapy."

He goes on to explain that while the rates of local recurrence were much higher in the women who

received ELIOT, for some women, the benefits of not having to undergo weeks of radiotherapy

outweigh a higher risk of the cancer returning.

He says it is also encouraging that after 5 years, deaths in the ELIOT and standard treatment

groups were no different.

Prof. Veronesi concludes that advances like the one they tested should help improve quality of

life for patients, and he hopes their findings will help clinicians make better use of all the

available medical information to help identify the patients most likely to benefit from the

treatment.

Experts say more research needed

In an accompanying comment on both studies, Prof. David Azria and Dr. Claire Lemanski, of the

Institut du Cancer Montpellier in France, say more research is now needed to find out which patients

are least likely to experience a return of their breast cancer after receiving radiation therapy at

the time of surgery, adding:

"The new data from TARGIT-A and ELIOT reinforce our conviction that intraoperative radiotherapy

during breast-conserving surgery is a reliable alternative to conventional postoperative

fractionated irradiation, but only in a carefully selected population at very low risk of local

recurrence."

Written by Catharine Paddock PhD

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