A large study found that the number of women who decided to have both breasts removed after being diagnosed with DCIS (ductal carcinoma in situ) in one breast more than tripled between 1998 and 2005.
Removing a breast that has no cancer in it is known as a prophylactic mastectomy. Removing both breasts is called double or bilateral mastectomy.
In an earlier study, the same researchers found a similar increase in the number of women choosing to have bilateral mastectomies after being diagnosed with invasive breast cancer in one breast.
In this study, the researchers looked at the medical records of more than 51,000 women diagnosed and treated for DCIS from 1998 to 2005. The likelihood that a woman would decide to have prophylactic mastectomy on the other healthy breast increased during the time studied:
- in 1998, 4.1% of the women had prophylactic mastectomy
- in 2005, 13.5% had prophylactic mastectomy
Women diagnosed with DCIS have a very good prognosis. Ten years after DCIS diagnosis, 98% to 99% of women will be alive. Based on this good prognosis, DCIS usually is treated by lumpectomy followed by radiation therapy. If the DCIS is large, a mastectomy may be recommended. Removing the opposite breast usually isn't recommended; chemotherapy usually isn't recommended either. Hormonal therapy may be recommended if the DCIS is hormone-receptor-positive.
DCIS is NOT invasive cancer. DCIS stays inside the breast milk duct. DCIS can be large or small, but it does NOT spread outside the milk duct into the surrounding normal breast tissue or into the lymph nodes or other organs. Still, if you've been diagnosed with DCIS, you're at higher risk of developing invasive breast cancer in that breast than someone who hasn't had DCIS. DCIS also is referred to as stage 0 breast cancer.
After a DCIS diagnosis in one breast, the average risk of developing either DCIS or invasive breast cancer in the OPPOSITE breast is small -- under 1% each year. The risk is higher for women who have an abnormal breast cancer gene (BRCA1 or BRCA2). Choosing to have both breasts removed after a DCIS diagnosis in one breast is very aggressive treatment. Yes, it does make it very unlikely that any type of breast cancer will be diagnosed again. Still, for women with no abnormal breast cancer genes, prophylactic mastectomy probably doesn't improve the excellent prognosis that comes with more conservative treatment approaches.
This study didn't ask why more women diagnosed with DCIS are choosing to have double mastectomy. But it's likely that the women are worried about developing breast cancer again in the future, in either the same breast where DCIS was found, or in the opposite breast. The study showed that younger women diagnosed with DCIS chose double mastectomy more than older women. This may be because younger women have more time ahead of them to possibly develop a second breast cancer. Reconstruction choices also may play a role in more women opting for double mastectomy. Women who chose mastectomy as the first treatment for DCIS also were more likely to have prophylactic mastectomy of the opposite breast, compared to women who chose lumpectomy as the first treatment for DCIS. Women may have chosen mastectomy because the DCIS was large, because of family history, or because they wanted to take a very aggressive treatment approach.
Every woman's situation is unique and every woman diagnosed with breast cancer, whether it's DCIS or invasive, has to ask herself this question: How much risk of the cancer coming back or a new cancer being diagnosed can I personally tolerate? Everyone will have a different answer to the question and the answer will affect how aggressive you want to be with treatment.
If you've been diagnosed with DCIS and are considering double mastectomy to reduce future risk, here are some things to consider:
What's your actual risk of developing a second breast cancer after treatment for DCIS?
It's important to talk about this with your doctor. Many women tend to overestimate their risk of breast cancer. This may be an unintended effect of great awareness of breast cancer. Before making any decisions about surgery, it's a good idea to figure out the risk associated with your unique situation.
What are your plans, if any, for breast reconstruction after surgery?
To achieve a balanced appearance, some women may need or want cosmetic surgery on the healthy breast after reconstruction. Also, some types of reconstruction can be done only once, which may limit reconstruction options for women who may need a second mastectomy if breast cancer is diagnosed later in the other breast. So some women may choose to have a double mastectomy and reconstruct both breasts at the same time. Your medical team, including a plastic surgeon, can help you make the best choice for you.
Do you have an abnormal BRCA1 or BRCA2 gene?
Some women may assume they have an abnormal breast cancer gene because someone in the family had breast cancer -- without ever having genetic testing and counseling themselves. Having an abnormal BRCA1 or BRCA2 gene has a big influence on the risk of developing breast cancer and on breast cancer coming back. If you're considering a double mastectomy because you MIGHT have an abnormal gene based on family history, talk to your doctor about whether genetic testing and counseling make sense for you. You may still decide to have a double mastectomy, but it's better to make the decision based on facts, not assumptions.
Can medicine lower my risk of developing breast cancer?
Removing a healthy breast essentially eliminates the possibility of breast cancer in that breast. Medicines that lower the risk of breast cancer don't offer the same certainty, but they may be another option to consider.
If you've been diagnosed with DCIS, talk to your medical team about ALL your treatment options so you can make the best decisions for YOU and your unique situation.