ALEXANDRIA, Va., Oct. 29 (UPI) -- Dutch researchers said Friday that the
anticancer drug tamoxifen may help prevent the spread of breast cancer
among women with a common genetic mutation.
In an article to be published in the November issue of the Journal of
Clinical Oncology, doctors reported that women with the gene known as
BRCA2 tend to develop breast cancers that would be sensitive to
tamoxifen.
Presently, doctors have few choices for preventing further bouts of
breast cancer for women with the genetic mutation: They can offer the
women more aggressive screening with mammography or they can offer
prophylactic mastectomy -- removal of the breast not yet affected.
Dr. Johannes Klijn of the Family Cancer Clinic at Daniel den Hoed
Klinick, Rotterdam, said, ''These findings lead us to suspect that
tamoxifen might prevent breast cancer in women with BRCA2 germline
mutations but not in women with BRCA1 mutations.''
The mutations in the BRCA genes are known to increase the lifetime risk
of breast cancer in women carriers by as much as 80 percent. About 5
percent to 10 percent of all breast cancer occurs in these germline --
hereditary -- mutations.
Klijn said his study revealed that women with the BRCA2 most frequently
develop tumors that depend on hormones such as estrogen for growth.
Tamoxifen, an anti-estrogen drug, is used in treatment and prevention
of breast cancer for women at high risk of the disease. Tamoxifen
deprives the tumors of estrogen.
Although tamoxifen is used in prevention of breast cancer in general,
scientists have not been able to determine exactly what the drug's role
would be in women with specific mutations.
''In the United States, tamoxifen is being used by some physicians to
treat women with the breast cancer mutations,'' said Mary Lynn Carver,
a spokeswoman for Zeneca Pharmaceuticals of Wilmington, Del., the
manufacturer of tamoxifen. ''The implications of the Dutch study make
sense,'' she said.
Ongoing studies in the United States are attempting to further define
the use of tamoxifen in patients with these mutations, she said.
In the study, Klijn and colleagues examined 28 breast cancer patients
in 14 families with eight different BRCA2 inherited mutations. The
researchers found that tumors associated with BRCA2 are ''steroid
receptor positive,'' therefore sensitive to the hormone estrogen. In
contrast, Klijn said cancers arising from BRCA1 gene -- are more likely
to be ''steroid receptor negative,'' and so less affected by hormone.
The researchers also found that women with BRCA2-associated cancers
have a similar prognosis compared to women whose breast cancer arises
either spontaneously or is due to BRCA1 mutations. After five years, 52
percent of both the BRCA2 patients and the other breast cancer patients
were disease free; overall survival was 74 and 75 percent,
respectively.
The only significant difference between the groups was that tumors
occurring in both breasts occurred five times more frequently in the
BRCA2 group, Klijn said. (Written by Ed Susman in West Palm Beach, Fla.)
