Partial-breast irradiation: treatments aim to ease radiotherapy after cancer.(Gynecology)

SAN ANTONIO -- Stung by criticism that the radiotherapy component of breast-conserving therapy is such an ordeal that many favorable candidates for breast conservation opt instead for mastectomy, radiation oncologists have responded by developing an array of far more patient-friendly accelerated partial-breast irradiation techniques.

Standard radiotherapy following lumpectomy entails 6-7 weeks of nearly daily whole-breast irradiation. It's a costly regimen. It's also inconvenient, particularly for the many women who live a long distance from a radiation treatment facility. So it's high time for some innovative thinking in the radiotherapy domain, oncologists agreed at a breast cancer symposium sponsored by the Cancer Therapy and Research Center.

"Essentially in the era of breast-conserving therapy we've moved from radical surgery to radical radiotherapy. All the fields that used to be treated surgically are now treated by radiotherapy," said Dr. Jayant S. Vaidya, a surgeon at University College, London.

The possibility that whole-breast irradiation might be more treatment than necessary was raised by landmark Danish studies showing 90% of breast cancer recurrences arise in the same quadrant as the index cancer regardless of whether radiation therapy is given. This observation sparked interest in preventing local recurrences while confining radiotherapy to the 10-15 mm of tissue surrounding the lumpectomy cavity.

In the United States, three forms of technology are being used for partial-breast irradiation. Interstitial catheter-based brachytherapy is the oldest, having been used at a few centers for as long as 10 years. It's also the only method for which 5-year follow-up data exist. Those recently published data showed that the local recurrence rate was only 1% at 65 months in 199 patients, essentially the same as in matched controls given standard whole-breast irradiation (J. Natl. Cancer Inst. 95[16]:1182-83, 2003). Cosmetic outcomes have been highly favorable, too, according to principal author Dr. Frank A Vicini of William Beaumont Hospital in Royal Oak, Mich.

An alternative is the MammoSite balloon catheter-based brachytherapy system designed for inflation inside the lumpectomy cavity. Since its marketing approval by the Food and Drug Administration less than 2 years ago, its use has escalated dramatically. It's easier to apply, more comfortable, and more reproducible than interstitial brachytherapy.

"Interstitial brachytherapy is difficult to teach and difficult to learn to do. And let's face it: putting anywhere from 15 to 20 catheters in a breast is not the easiest thing to sell to a patient," Dr. Vicini noted.