prophylactic mastectomy benefits women at high risk of hereditary breast
cancer, according to a presentation at the 38th Annual Meeting of the American
Society of Clinical Oncology (abstract 1694). The study revealed the presence
of high-risk premalignant lesions in the removed breast tissue of more than
half of the women undergoing the procedure.
"As a physician, I would want to have as much information as
possible to guide my patients at high genetic risk of breast cancer through the
difficult decision of whether or not to have a prophylactic mastectomy," said
presenter and lead author Nicoline Hoogerbrugge, MD, of University Medical
Center Nijmegen, The Netherlands. "But unfortunately, very little is known
about the early stages of hereditary breast cancer," including the frequency of
atypical hyperplasia and ductal carcinoma in situ (DCIS).
This prospective study examined breast specimens from 67
women who underwent prophylactic mastectomy in a tertiary referral center
because they were thought to have a greater than 30% lifetime risk of breast
cancer. Palpation and mammography before mastectomy did not detect breast
lesions in any of the women, nor did MRI in the 50% of women who also had that
The average age of the women was 39; two thirds (67%) were
carriers of a BRCA1 or BRCA2 mutation, 25% had had a prophylactic oophorectomy,
and 38% had had previous breast cancer. Only one removed breast from each woman
The investigators performed radiographic and macroscopic
examinations of 5-mm tissue slices from suspicious lesions and from random
samples from each quadrant of the breast and the nipple area (a mean of 19
samples per breast). The exams revealed one or more different types of
high-risk histopathologic lesions in 57% of the women.
These included atypical lobular hyperplasia in 37%, atypical
ductal hyperplasia in 39%, lobular carcinoma in situ in 25%, and DCIS in 15%.
One woman had a 4-mm invasive carcinoma.