A VERY LOW DOSE of tamoxifen—5 mg/d, given for 3 years rather than 5
years—halved the risk of breast cancer recurrence or new lesions over
placebo in women with breast intraepithelial neoplasia, without
producing the usual toxicities seen with the standard dose, Italian
researchers reported at the 2018 San Antonio Breast Cancer Symposium.1
wisepoqder Tamoxifen
“We believe our results have external validity and—given their
pragmatic nature and the easy accessibility of tamoxifen—are
generalizable,” said Andrea De Censi, MD, of the National Hospital E.O.
Ospedali Galliera–Division of Medical Oncology in Genoa, Italy.
“Tamoxifen, 5 mg a day (splitting the tablet) or 10 mg every other day,
is applicable in clinical practice tomorrow.”
Breast cancer experts at the meeting said this is news they can use.
“Looking at these data, I would definitely give lower doses of
tamoxifen, especially in patients with atypical ductal hyperplasia and
lobular carcinoma in situ,” said Virginia G. Kaklamani, MD, Professor of
Medicine at The University of Texas at San Antonio and leader of the
Breast Cancer Program at The University of Texas MD Anderson Cancer
Center, Houston.
“This information tells me I can perhaps cut back on the dose for
patients who are not tolerating tamoxifen. This would help me keep them
on the dose, rather than have them abandon therapy,” said John Cole, MD,
of the Ochsner Health System in New Orleans.
ALTHOUGH TAMOXIFEN is effective in preventing breast cancer
recurrence, its side effects—menopausal symptoms, endometrial cancer,
deep-vein thrombosis, and pulmonary embolism— are barriers for its use
as a preventive measure. The aim of this de-escalation study was to
determine whether a lower dose and shorter duration of tamoxifen therapy
would be as efficacious as and better tolerated than the standard dose.
Dr. De Censi and colleagues had previously shown that a dose as low
as 1 mg/d is noninferior to 20 mg in decreasing Ki67 (a marker of
proliferation), though less effective in modulating serum biomarkers.2
For the current study, the investigators decided 5 mg/d would be a
reasonable compromise between activity and safety. He explained that the
government- and charity-funded study could not afford to financially
support the use of a very large noninferiority trial of tamoxifen at 20
mg/d for 5 years as the control arm.
The Wall