Predictive molecular testing for tailoring post-lumpectomy RT indications?

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Palex80

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Interesting article pointing out, that you cannot tailor the indication to adjuvant post-lumpectomy radiation therapy by molecular testing:

http://www.ncbi.nlm.nih.gov/pubmed/25867274

I am curious to see how this story goes... Oncotype Dx has shaken up alot the adjuvant chemo setting for the med. oncologists. The same company is also providing a test for DCIS.

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I've had med oncs try to use oncotype DCIS assays to guide management without talking to me first, in women under 70 years of age no less.

It's not even recognized in the nccn guidelines, which is why I always try to make sure the surgeons send a referral to both of us
 
What are some talking points that people use against OncotypeDCIS? I've never ordered one, nor do I plan to.

The ECOG study on which it was based was the best of the best actors only. I'm not aware of any prospective or external, retrospective validation. The curves for recurrence look way to flat to be useful for me. The top end of the "low-risk" recurrence strata is 17% recurrence, whereas the bottom of the "high-risk" group is 22%. Seriously? 5% difference places you from low-risk to high-risk? Also even with a recurrence score of 0, you're at a non-trivial 10% risk of recurrence. Radiation will reduce that risk by ~5% (also known as the difference between their low and high risk groups). Why would that 5% not be equally important?
 
The purpose of the ECOG study was to investigate if women with suitably low-risk DCIS could avoid radiation and still have "acceptably" low rates of in-breast recurrence. As such, using the ECOG data set to validate a genomic test like Oncotype skews thing to be inappropriately low risk.
 
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