John Einck, MD
Kerri Perry, MD, FACS

The use of accelerated partial breast radiation (ABPI) as part of breast conservation therapy for patients with ductal carcinoma in situ (DCIS) has been an ongoing controversy in the treatment of early-stage breast cancer. In 2010, the American Society of Radiation Oncology (ASTRO) issued patient selection guidelines advising that the use of APBI in patients with DCIS is “cautionary,” due to a lack of long-term data. However, many physicians believe emerging data sufficiently supports the use of APBI in select patients, and that the ASTRO guidelines are unnecessarily conservative.

According to a new study presented at the recent meeting of the American Society of Breast Surgeons (ASBrS), APBI appears to be an effective treatment for patients with DCIS, resulting in favorably low rates of recurrence and toxicity. Researchers reported on 265 patients, making it the largest study of DCIS patients treated with APBI to date.

Lead author and radiation oncologist John Einck, MD, and co-author and breast surgeon Kerri Perry, MD, FACS, discuss their views on the controversial subject, including what the results of their groundbreaking study mean for the future of DCIS treatment.

What are your thoughts on the ASTRO consensus guidelines for APBI that place DCIS patients in the “cautionary” group?

John Einck, MD: Many of the physicians that perform APBI with brachytherapy believe that the ASTRO consensus guidelines listing its use as “cautionary” are too restrictive, but it is an evidence-based guideline and the percentage of patients with DCIS that were included on trials was fairly low. Recent single institution reports and the results from a relatively large group of patients with DCIS treated on the ASBrS MammoSite registry trial show excellent control rates for both low/intermediate and high grade DCIS. With those results and more long term follow-up of our SAVI-treated patients, DCIS will likely be taken out of the “cautionary” group in the future.

Kerri Perry, MD: I don’t necessarily agree with placing DCIS patients in the cautionary group. I don’t see how it’s any different from treating invasive cancers with APBI. Based on the current data, as long as it’s used in appropriate patients (i.e. those with small, unifocal lesions), the risk of recurrence is the same as with whole breast radiation. Unfortunately, the ASTRO consensus statement is restricting access to APBI for certain eligible women, as it makes some physicians hesitant to offer it. In addition, some insurance companies have refused to cover the use of APBI for DCIS, labeling it as experimental for these patients based solely on the ASTRO guidelines. This is a shame, particularly for women with very small cancers who end up having whole breast radiation because they have no other options.

How does your research presented at ASBS add to the current literature on treating DCIS with APBI?

Dr. Einck: To my knowledge, this is the largest group of DCIS patients treated with APBI to be presented thus far. Our follow-up remains quite short but so far we have both excellent control rates and low toxicity.

Dr. Perry: Our study shows very low rates of recurrence that compare favorably with the data that is available for whole breast radiation. Considering this is the largest study of DCIS patients treated with APBI, this is very significant, as it adds further support to the current literature that APBI is an appropriate treatment for these patients.

How often do you treat DCIS patients with APBI?

Dr. Einck: Most women with small areas of DCIS removed will choose APBI even when I explain that it is in the “cautionary” category in the ASTRO guidelines. Therefore we treat approximately 5-10 DCIS patients annually with APBI at UCSD.

Dr. Perry: I regularly treat DCIS patients with APBI, almost on a weekly basis.

How do you determine which DCIS patients are suitable for APBI? Does the grade of the diagnosis affect your decision?

Dr. Einck: I am still hesitant to treat women under 50 who have DCIS with APBI off protocol because these patients are eligible for NSABP B-39. However, if they are 50 years or older and have completely excised DCIS with margins > 2 mm, I will offer them APBI even if high grade.

Dr. Perry: As long as a patient is over 40 with a tumor size of 3 cm or less, and advanced breast imaging has ruled out evidence of multifocal disease, I feel confident that APBI is a sufficient treatment. However, I think the most important thing is to realize that when it comes to breast cancer treatment, there is no one-size-fits-all criteria that works for everyone. You have to utilize your best clinical judgment, take all the factors into account and determine the most appropriate treatment for the individual patient.

What kind of discussion should physicians have with DCIS patients regarding the benefits and risks of APBI?

Dr. Einck: I think women over 50 with good surgical margins should be counseled that DCIS is listed as “cautionary” but that there is very sound emerging data that control rates in DCIS patients are excellent with APBI.

Dr. Perry: I discuss the various options, explaining that while the data for APBI isn’t as mature as the literature supporting whole breast radiation, the 10-year follow-up that we do have basically shows that the risk of recurrence is the same. I also explain that choosing APBI would allow them greater options for breast conservation in the future if they were to have a recurrence or a second cancer.

What are physicians’ main concerns about treating DCIS patients with APBI, and how would you respond to those concerns?

Dr. Einck: The main concern that does not have strong data support is that DCIS is more often multifocal and may extend farther through the adjacent breast tissue than an invasive ductal cancer. I would suggest that if good surgical margins are obtained at the time of lumpectomy, this argues against the disease being multifocal and widespread and that if over age 50, APBI provides excellent control. Recurrences distant from the tumor bed in these patients are very uncommon.

Dr. Perry: I think the biggest concerns are local recurrences and elsewhere failures, or developing DCIS in the future. But I would argue that based on the current data we have, including the ASBrS MammoSite registry and our study that was presented at ASBrS, for the appropriately chosen patients, there is no increased risk of local recurrences or elsewhere failures compared to whole breast radiation.

As more research continues to show APBI is an appropriate treatment for DCIS patients, why are some physicians still hesitant to change their treatment recommendations?

Dr. Perry: I think a lot of physicians want long-term data before they feel comfortable offering APBI to this particular group of patients, just as there were many physicians who were hesitant to adopt APBI at all until five-year data was available. But the benefit of our study, particularly given its size, is that it gets us another step closer towards making physicians more comfortable that this is an appropriate treatment option, which will hopefully expand access to APBI for eligible women.

Dr. Einck is a radiation oncologist and associate clinical professor of radiation oncology at the UC San Diego Moores Cancer Center in La Jolla, Calif.

Dr. Perry is a board certified breast surgeon with a private practice located in Denton, Texas.