San Antonio Breast Conference...

[OTN]

Two things to discuss:

1. Increased risk of mastectomy (4 vs 2.2%) for pts treated with APBI c/w whole breast RT. Historical (Medicare claim) data. Increased risk of complications with APBI as well.

2. OncotypeDX-type test detecting risk of recurrence for pts with DCIS without adjuvant radiation or hormone therapy. 75% of pts fall into "low-risk" category.

APBI data being presented today, #2 tomorrow. Only info available right now: http://www.sabcs.org/PressReleases/index.asp

Obviously, going to have to wait to see the details of the data, but...thoughts?

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[Gfunk6]

1. Increased risk of mastectomy (4 vs 2.2%) for pts treated with APBI c/w whole breast RT. Historical (Medicare claim) data. Increased risk of complications with APBI as well.

This was highly surprising. In the press release, the lead author stated that they did not expect to find a difference in efficacy only in side effects. With that said, I think APBI is misused, particularly in the community. Too many Radiation Oncologists have migrated to this technology and are using it relatively indiscriminately.

Also, I find it funny how APBI proponents are spinning this finding saying that "patients may have had mastectomies for reasons other than tumor recurrence." Seriously?

2. OncotypeDX-type test detecting risk of recurrence for pts with DCIS without adjuvant radiation or hormone therapy. 75% of pts fall into "low-risk" category.

This is a very promising study. Since few of us have pathology labs capable of the meticulous specimen analysis for applying the Van Nuys prognostic index, a gene-chip based assay would be great. Identifying women who are very low risk for recurrence and sparing them five weeks of XRT would be ideal.

 

[OTN]

I see the first study as merely adding to the large body of non-RCT literature in the APBI field.

So, still "waiting for B39" to some extent. Samuel Beckett would be pleased.

My surprise at the DCIS gene chip analysis mostly arises from the % of patients who, in their study, would have been in the "low risk" category: 75%. That would mean the clinical benefit documented in all the NSABP randomized data was coming from only 1/4 of the patients, suggesting a subpopulation with a very high recurrence rate. Certainly could be true, but not what I would have expected.

 

[seper]

Also, I find it funny how APBI proponents are spinning this finding saying that "patients may have had mastectomies for reasons other than tumor recurrence." Seriously?

Yes, seriously. For example, early in MammoSite experience rate the rate of unnecessary mastectomy for fat necrosis was high in the community setting. People were spooked of recurrences. I've seen the discussion about this at 2010 ABS annual meeting. However, for obvious reasons, rate of unnecessary mastectomy is not well reported in single-institutional studies that still comprise the bulk of breast brachytherapy published data.

 

[Gfunk6]

Yes, seriously. For example, early in MammoSite experience rate the rate of unnecessary mastectomy for fat necrosis was high in the community setting. People were spooked of recurrences. I've seen the discussion about this at 2010 ABS annual meeting. However, for obvious reasons, rate of unnecessary mastectomy is not well reported in single-institutional studies that still comprise the bulk of breast brachytherapy published data.

Interesting. Do you have a link to this data?

 

[seper]

No, I'm unable to provide a citation, but will try to obtain.

 

[medgator]

In the WSJ yesterday...

New Scrutiny for Popular Breast-Cancer Treatment

An increasingly popular strategy that shortens radiation treatment for patients with early-stage breast cancer is drawing scrutiny from researchers concerned that it is being rapidly adopted before important questions are answered about its efficacy.

Known as accelerated partial-breast irradiation, the treatment involves five days of twice-daily doses of radiation delivered to a targeted area of the breast. By comparison, whole-breast irradiation, considered the standard of care, requires six to eight weeks of daily treatment.

Both treatments are given after patients undergo a lumpectomy to remove cancerous tissue and to avoid losing the entire breast to a mastectomy.

 

[Sheldor]

Anyone hear the APBI brachytherapy discussion on morning edition today?

Thought they seemed a little harsh. Also they referred to the doctor as a "radiation specialist."

 

[medgator]

Today was my 8 minute commute, so unfortunately I didn't get much NPR time in the car Sounds like they brought up the recent MDACC data regarding increased mastectomies in APBI patients

http://www.npr.org/blogs/health/201...ast-cancer-radiation-technique-raises-concern

In recent years, the popularity of the therapy has soared, rising from less than 1 percent of patients in 2001 to 10 percent in 2006, Vikram says.

"So it was a tenfold increase over a five-year period," he says.

Vikram worries there's not enough proof yet that brachytherapy is as effective as what doctors have been using for years. And, he notes, there are some big concerns: "That the tumor will recur and women will need more mastectomies, and/or the tumor may spread to other parts of the body and kill the woman, or it may have more toxicity in the long-term."

Those fears spiked in December when Benjamin Smith of the M.D. Anderson Cancer Center in Texas unveiled the results of a big study at a scientific meeting in San Antonio.

"We found that the decision of whether or not a patient was treated with brachytherapy or whole breast irradiation was the single most important predictor of whether they had a mastectomy within five years of their cancer diagnosis," Smith says.

Mastectomies were rare no matter what kind of radiation women got. But they were about twice as common among the women who got brachytherapy, Smith and his colleagues found. That's a red flag that brachytherapy might not be snuffing out the cancer as well, Smith says.

"The most plausible explanation for our data is that women treated with brachytherapy were at increased risk of having a recurrence of cancer in their breast," he says.

Smith and his colleagues also found that women getting brachytherapy were also more likely to experience minor complications, such as infections and bleeding.

"When you put together significantly increased risk of a lot of different complications and a treatment that's slightly less effective potentially than whole breast irradiation, then you start to wonder, 'What is the role of this treatment? And have we adopted it too quickly before we really understand how to use it correctly?' " Smith says.

 

[Sheldor]

They did reference the above study. Against APBI they interviewed someone at the NCI and used the above study. For APBI they interviewed a patient and two physicians. It felt lop sided, to say the least.

 

[Gfunk6]

The MDACC SEER analysis is another good excuse not to discuss APBI on oral boards.

 

[deleted4401]

based on discussion with an examiner, you'll be expected to know indications (suitable patients) and to be able to describe a technique, i.e. following B39's parameters essentially

 

[Gfunk6]

Good point. Just one more thing on the list of stuff to memorize . . .

 

[medgator]

The MDACC SEER analysis is another good excuse not to discuss APBI on oral boards.

Until they decide to ask you about it point blank Just be safe and stick with the more conservative ASTRO criteria (unless you get one of the APBI big-whigs as your breast examiner haha).

 

[RadRadRad]

My surprise at the DCIS gene chip analysis mostly arises from the % of patients who, in their study, would have been in the "low risk" category: 75%. That would mean the clinical benefit documented in all the NSABP randomized data was coming from only 1/4 of the patients, suggesting a subpopulation with a very high recurrence rate. Certainly could be true, but not what I would have expected.

Note that the DCIS oncotype was performed in a highly select group of patients, namely those that qualified for the ECOG phase II no RT study. This does not represent the "average" patient with DCIS at least in the NSABP RCTera (ie by simply being enrolled in the ECOG study, regardless of the oncotype, almost all patients were low risk based on clinical factors. Specifically to be in ECOG, you had to have low/int grade DCIS, <2.5cm or high grade <1cm both with >3mm margins. Moreover the median size was ~6mm. So its not really that surprising that 75% of patients with mainly low grade, 6mm size DCIS don't benfit from RT.

In my opinion equally interesting was that while at 5 yrs the low/int grade group had ~6% recurrence and the high grade had ~15% recurrence in the 10 yr follow up (presented with the oncotype data) the low grade was up to 15% while the high grade basically remained roughtly stable at 15% LRR.

Admittedly if this pans out prospectively it would be quite useful.