Time
to response with neoadjuvant endocrine therapy
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We
did some work looking at that with tamoxifen and what we found is
that if you didn’t get a response by three months, if you don’t
have a change in tumor volume – measurable mammographically
and on ultrasound, and we believe from our studies that if you don’t
have a 25% reduction in tumor volume by three months – then
the chance of getting a reduction in tumor volume is not very good.
And the concern is that an equivalent number of patients from three
to six months get a response to the number of patients whose disease
starts to grow. So, yes you do get some response after three months,
but you also start to get similar tumors growing out of control.
So that’s why we have tended to use a three month period, and
we get significant reductions in tumor volume during that period
of time. It allows us, in the large majority of patients, to get
sufficient reduction to avoid mastectomy. And in the studies we’ve
done on local control, rates are really excellent.
Biologic
markers as predictors of clinical outcome from systemic therapy
for primary operable breast cancer. Chang J. Powles TJ. Allred DC. Ashley SE. Clark GM. Makris A.
Assersohn L. Gregory RK. Osborne CK. Dowsett M. Journal of Clinical
Oncology. 17(10):3058-63, 1999.
