已知基因BRCA1和BRCA2突变（mutations in the genes BRCA1 and BRCA2）的女性日后患乳腺癌与卵巢癌之风险非常高。最近发表于癌症杂志的文章披露，高达80％被检测发现上述基因突变的美国女性选择了预防性手术切除她们的子宫和/或卵巢。女士们的这一行为是否偏激？是否必要？难道她们疯了吗？对此，专家们评价不一！但我个人认为，如此多的女性因检测出上述基因突变而惧怕癌变选择预防性接受乳房和/或卵巢切除手术实属过分。因为癌变有一个过程，对于携带有上述基因突变的女性只要坚持定期检查，如磁共振和免疫学检查，及乳房自查等，就可以尽早发现异常而对其进行治疗。我同意某些专家的观点，即如果某某女士上述基因突变，且家族中还有1或多名一级亲属曾患乳腺癌或卵巢癌，或两者兼有，则可能需要慎重考虑是否该预防性接受乳房和/或卵巢切除？更多资讯，请参阅原文：

Most women carrying cancer genes take action: study

NEW YORK (Reuters Health) - Women who screen positive for gene mutations that promote breast and ovarian cancers usually opt for surgery to cut their risk of the diseases, a new study suggests.

The research, reported in the journal Cancer, followed 465 women who were tested for mutations in the genes BRCA1 and BRCA2 that substantially boost the lifetime risks of breast and ovarian cancers.

It found that more than 80 percent of women who tested positive for the harmful mutations ultimately chose to have surgery to remove their ovaries, breasts or both.

　　"Almost all of the women who screened positive did take some sort of action," said lead researcher Dr. Marc D. Schwartz, of the Lombardi Comprehensive Cancer Center in Washington, D.C.

That may not seem surprising. But Schwartz said there has been some skepticism about how many women with BRCA mutations would choose to have their ovaries or breasts removed.

"It's a difficult decision to have prophylactic (preventive) surgery," Schwartz noted in an interview.

"There's been a perception that risk-reducing surgery, especially risk-reducing mastectomy, was not something most mutation carriers would choose," he said.

But most studies on the issue, at least in the U.S., have been short-term -- looking at women's choices in the year or so after a BRCA test result. Women in the current study were followed for an average of just over five years.

Defects in the BRCA1 and BRCA2 genes substantially raise a woman's lifetime risks of breast and ovarian cancers -- to a roughly 60 percent chance of developing breast cancer, and a 15 to 40 percent risk of ovarian cancer.

By comparison, the average U.S. woman has a 12 percent chance of developing breast cancer during her lifetime and only a 1.4 percent chance of ovarian cancer.

Because of the high risks, experts recommend that some women with a strong family history of breast or ovarian cancers be screened for the gene mutations.

For women who test positive, it's a "pretty firm recommendation" that they have their ovaries removed by about age 40, Schwartz said.

That's because ovarian cancer is difficult to catch early and, therefore, has a high death rate. And studies have found that when a woman has a BRCA mutation, surgery to remove the ovaries not only slashes her risk of developing the cancer by about 90 percent, but can also extend her life.

The recommendations on preventive mastectomy are less firm, Schwartz said.

The surgery does cut carriers' risk of breast cancer by roughly 90 percent. But removing just the ovaries is effective as well -- cutting a mutation carrier's breast cancer risk in half, because removing the ovaries takes away the body's main source of estrogen.

And unlike ovarian cancer, breast cancer can often be detected early: For women with BRCA mutations who choose not to have a mastectomy, experts recommend regular screening with not only mammography, but also MRI scans, which are better at spotting breast tumors in their earliest stages.

Of the 465 women tested in the current study, 31 percent were found to carry BRCA mutations.

There were 100 mutation carriers who still had their ovaries, and two-thirds ultimately opted to have their ovaries and fallopian tubes removed.

　　And of 108 mutation carriers who still had at least one breast, 37 percent chose to have a mastectomy.(Most of the women in the study had already been diagnosed with breast or ovarian cancer when they decided to have BRCA testing, so some had previously had one breast or their ovaries removed.)

The U.S. Preventive Services Task Force, an expert panel supported by the federal government, recommends that women with certain family-history patterns of breast or ovarian cancers consider BRCA testing.

That includes women who've had: two first-degree relatives (mother, sister or daughter) diagnosed with breast cancer, one of whom developed the disease by age 50; three or more first- or second-degree relatives diagnosed with breast cancer at any age; two or more first- or second-degree relatives with ovarian cancer. The full task force recommendation can be viewed here: http://bit.ly/p2aiWD.

About 2 percent of U.S. women would meet the criteria for considering BRCA testing, according to the USPSTF.

According to Schwartz, the current findings "lend credence" to the belief that BRCA testing will ultimately make a difference in carriers' risk of developing breast and ovarian cancers, and possibly extend their lives.

The primary limitation of the study, he said, is that all of the women were tested and received genetic counseling at a single medical center. "Out in the world, the results may be different," Schwartz said.

Individual doctors can, and increasingly are, ordering BRCA testing. And women may or may not get the genetic counseling that's recommended for helping them decide what to do with the test result.

And that result is often not straightforward. Many women get what's called an "inconclusive" or "uninformative" result: They do not have a known BRCA mutation, but the possibility that they have some genetic abnormality cannot be ruled out.

That's in contrast to a "true negative" BRCA result -- where a woman tests negative for mutations that had previously been found in a family member.

For women with an inconclusive result, Schwartz said, genetic counseling can help them decide what to do.

If their family history of breast or ovarian cancers is very strong, it might be assumed that there is some sort of genetic risk. So they might still consider preventive surgery or possibly regular MRI screening for breast cancer.

SOURCE: http://bit.ly/kQfXNS Cancer, online June 29, 2011