Devices Oncology

 News Release - May 1, 2012

Brachytherapy as Effective for Local Breast Cancer Control as Whole Breast Irradiation According to New Study

Findings Contradict Research Published in May JAMA

May 1, 2012, Columbia, MD--(Healthcare Sales & Marketing Network)-- Accelerated Partial Breast Irradiation (APBI) also known as brachytherapy, is equally effective--if not more effective-- in preventing local breast cancer recurrence than Whole Breast Irradiation (WBI), according to a study to be presented this week at the American Society of Breast Surgeons (ASBrS) Annual Meeting. Brachytherapy treats only the lumpectomy site, while WBI treats the entire breast. The findings of the ASBrS study contrast with a study from the University of Texas MD Anderson Cancer Center appearing in the May issue of the Journal of the American Medical Association (JAMA).

Researchers will report on data from the ASBrS MammoSite Registry Trial comprising 1449 breast cancer patients treated with APBI brachytherapy at 97 institutions between May 2002 and July 2004. Eighty-seven percent of these patients were diagnosed with invasive breast cancer and 13% with DCIS, with a median follow up of 60 months.

In the ASBrS study, 50 patients treated with brachytherapy (3.5%) developed an ipsilateral breast tumor recurrence (IBTR), 14 (1.1%) at the initial tumor site and 36 (2.6%) elsewhere in the breast. For invasive cancers, IBTR was associated with estrogen receptor (ER) negative disease. For DCIS, IBTR was associated with age <50 or close/positive surgical margins.

“Prior studies have demonstrated that the risk of cancer recurrence in the conserved breast is similar for WBI or APBI. Following WBI, most breast recurrences are at the initial tumor site, and relatively few are elsewhere in the breast,” says Dr. Peter Beitsch, Director of the Dallas Breast Center, Co-Principal Investigator for the ASBrS MammoSite Registry and lead author on the ASBrS study. “This study demonstrated that for patients treated with APBI, this ratio was reversed: most breast recurrences were elsewhere in the breast and only a minority were at the initial tumor site. These data suggest that although tumor control in the breast appears to be similar for APBI and WBI, disease control at the initial tumor site may be better with APBI.”

The findings of the ASBrS study contrast with the MD Anderson Cancer Center JAMA study, which also compared APBI to WBI. That study compared the results of breast brachytherapy to WBI in 92,735 women 67 or older, 7% treated with brachytherapy and 93% with WBI. At 5 years of follow-up, compared to WBI, survival was the same (87.6% vs. 87%) but the brachytherapy patients had higher rates of subsequent mastectomy (4% vs. 2%), infectious complications (16% vs. 10%), non-infectious complications (16% vs. 9%), pain (15% vs. 12%), fat necrosis (8% vs. 4%) and rib fracture (4.5% vs. 3.6%).

Dr. Beitsch notes that the limitations of the MD Anderson study are that 1) it is based on Medicare claims data, which often does not provide an accurate clinical picture, 2) many endpoints are “soft”, poorly defined and difficult to quantify, 3) reported complication rates after breast surgery and radiotherapy vary widely, and depending on study design are subject to under- or over-reporting, and 4) the authors’ inferences of harm to patients from breast brachytherapy are at best speculative.

An extensive body of literature, drawing on the ASBrS Registry and other sources, suggests that for APBI 1) local control is comparable to WBI, 2) local control is similar for women younger vs. older than age 70, 3) infectious complications are similar, 4) non-infectious complications including fat necrosis are similar, 5) pain is comparable, 6) cosmesis is excellent, and 7) survival, including overall, disease-free, and disease-specific survival, is similar to WBI.

Standard treatment for early stage breast cancer often involves breast conserving surgery (lumpectomy) and WBI. Clinical trial data clearly demonstrate the need for some form of radiation therapy following lumpectomy to reduce the rate of tumor recurrence. APBI may offer advantages such as reduced treatment time, reduced radiation dose to normal tissue such as lungs, ribs and heart, increased utilization of postoperative radiation therapy leading to lower recurrence rates, and an increased rate of lumpectomy compared to mastectomy in areas with limited patient access to WBI centers.

Dr. Beitsch also notes: “We radiate the breast to control undetectable cancer cells left behind around the lumpectomy cavity. Common sense would say internally targeted radiation would be the best method to kill these cells. We now have strong data to support that, and that the complication rate is very low from this form of therapy.”

“APBI appears to be safe and effective treatment for properly selected breast conservation patients,” says Dr. Hiram S. Cody III, Attending Surgeon, Breast Service Department of Surgery, Memorial Sloan-Kettering Cancer Center and Professor of Clinical Surgery, Weil Cornell Medical College. Dr. Cody, who is also a member of the Executive Committee and Board of Directors for ASBrS, notes that the ASBrS continues to support its Consensus Statement on APBI and guidelines for patient selection (August 15, 2011 revision): (http://www.breastsurgeons.org/statements/PDF_Statements/APBI.pdf).

However, Dr. Cody also states, “We wish to emphasize that although the six year results of APBI are encouraging, they do not conclusively establish equivalence with WBI, for which the supporting data include multiple randomized trials with follow-up exceeding 20 years, and meta-analyses that conclusively link local control and survival. APBI must ultimately be held to the same standard, and a randomized trial, NSABP B-39, directly compares partial breast irradiation (by interstitial catheters, balloon devices, strut-based devices, or external beam) with WBI and promises to better define the ultimate role of APBI.”

Source: The American Society of Breast Surgeons

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