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Guide 02- Surgeons: Richard
Margolese, MD
Edited comments by Dr Margolese
Prior NSABP clinical trials in patients with
DCIS
B-17 was a trial comparing lumpectomy with or without radiation.
Local control was improved with radiation; it cut recurrences in
half for both invasive and noninvasive cancers. Overall survival
was essentially the same for both groups, and the incidence of breast
cancer related deaths was exactly as expected, a little over one
percent.
The results from B-17 were very reassuring. The study proved that
DCIS is a locally controllable disease, and that just like in invasive
cancer, radiation therapy helps with local control.
B-17 set the stage for testing the role of adjuvant tamoxifen.
So, B-24 was virtually the same protocol in terms of eligibility
and characteristics of the patients. In B-24, adding tamoxifen to
radiation and lumpectomy improves disease control even more than
radiation alone.
NSABP B-35: Anastrozole versus tamoxifen
It is clear that DCIS is a highly curable disease from which almost
no one should die. If tamoxifen and radiation therapy can reduce
the incidence of future invasive cancer to less than two percent,
can we achieve even better results?
On the other hand, there are more promising drugs, such as anastrozole.
I think it is worthwhile to test anastrozole and see if the small
amount of undesired recurrent cancers can be negated. The question
becomes: Will anastrozole be any better than tamoxifen and at what
risk?
NASBP B-35 is a large study with 3,000 patients, which will go
on for the next five years. It is restricted to postmenopausal patients
with DCIS who have ER-positive tumors. Studies in the advanced and
adjuvant settings found that anastrozole was at least as good as
tamoxifen and perhaps superior. Also, the toxicity was less worrisome
— anastrozole doesn’t cause uterine cancer or thromboembolism.
The issues with anastrozole are that it can’t be used in premenopausal
women and that it may cause osteoporosis, which can be a serious
cause of mortality in elderly women.
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