Problems with New Breast Cancer Radiation Study

There’s plenty of controversy about – and disagreement with – a new study from MD Anderson (MDA). One expert MD even said the study’s flaws were not trivial, but “huge.”

The study said women who got an older form of breast brachytherapy appear to have slightly higher rates of complications and subsequent mastectomy. Presented at this week’s San Antonio Breast Cancer Symposium, it was a “look-back” at Medicare records.

The MDA conclusions have prompted unusually strenuous objections from physicians who support and perform breast brachytherapy.

Breast brachytherapy, a form of accelerated partial breast irradiation (APBI), is increasingly popular because of its clinical efficacy for appropriate patients, and because it takes just 5 days.

By comparison, the standard course of external-beam, whole-breast irradiation (WBI) takes six or seven weeks. Many early-stage breast cancer patients increasingly express a preference for the far more convenient approach of APBI.

Follow-up radiation is recommended for women who have a lumpectomy as part of breast-conservation therapy. APBI now accounts for an estimated 13% of patients undergoing treatment in 2007, according to MDA’s Dr. Benjamin D. Smith, lead author of the study.

But are the study’s conclusions valid? And what are doctors saying to their patients about breast cancer treatment – especially given that the study data covers a period before more sophisticated APBI became available? (After all, even MD Anderson isn’t changing the way it offers APBI.)

“Criticism of the study surfaced almost immediately,” noted the respected radiology website “One critique was that the study is based on an analysis of Medicare billing codes rather than actual clinical outcomes.” Medicare claims data is often not a reliable measure of clinical effectiveness.

Also weighing in was the American Society of Breast Surgeons, which represents physicians who place the catheters that deliver breast brachytherapy.

ASBrS maintains a registry of 1440 patients treated by APBI with the balloon catheter device through 2004. It statement said numerous published studies have shown:

— A 5-year local cancer-recurrence rate of <5%, comparable to that of WBI;

— A low rate of other complications with APBI; and

— Good or excellent cosmetic results in approximately 90% of patients.

ASBrS noted that several randomized and nonrandomized studies using another technique of APBI — multiple interstitial catheters — have also seen rates of local cancer recurrence comparable to WBI.

For the record, Dowling & Dennis represents a company that makes one of those multiple interstitial catheters. It’s called SAVI – and it was developed to address the shortcomings of earlier brachytherapy technology, the one examined in the MDA study.

For more information on the experiences of women who’ve had SAVI treatment, see SAVI Sisters. Study data on SAVI is available here. In particular see the peer-reviewed, published results in the respected Red Journal (abstract available here.)

Other concerns about the MD Anderson study include:

— “Patients in this study received antiquated technology,” according to Robert Kuske, M.D., the principal investigator in a landmark trial comparing breast brachytherapy to traditional WBI. “Single-lumen balloons are being replaced with newer multichannel devices that allow much greater control of the radiation dose received by skin or ribs.”

— Said Dr. Frank Vicini, “All this study tells us is that when billing codes are analyzed, there appear to be differences in outcomes based upon billing-code surrogates for clinical outcomes. You can’t turn something nonclinical into clinical.”

Dr. Vicini is a Michigan radiation oncologist who publishes outcomes data comparing 199 APBI patients to 199 patients getting conventional treatment.

“Although the authors acknowledge the flaws in their study, these are not trivial,” he told AuntMinnie. “In my opinion, they are huge.”

So how should women and their families regard the controversial new study?

In urging breast cancer patients to participate in clinical studies when possible, the American Society of Breast Surgeons had this to say:

“The evidence in the MD Anderson study should be considered in pre-surgical counseling — but is not strong enough to preclude the use of APBI in properly selected patients.”

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