Women diagnosed with DCIS (ductal carcinoma in situ) have a higher risk of being diagnosed with invasive breast cancer in the same breast in the future, compared to women not diagnosed with DCIS. A study suggests that certain genetic characteristics -- called biomarkers -- in DCIS cells may help predict the risk of future invasive breast cancer.
The study also discovered that DCIS found during a physical exam or breast self-exam (doctors call this "detected by palpation") was linked to a higher risk of developing invasive breast cancer in the future compared to DCIS discovered by mammogram.
DCIS is not invasive cancer and is called stage 0 breast cancer. DCIS stays inside the breast milk duct and doesn't spread outside the milk duct into the surrounding normal breast tissue, lymph nodes, or other organs.
Women diagnosed with DCIS have a very good prognosis. DCIS usually is treated by lumpectomy followed by radiation therapy. If the DCIS is large, doctors may recommend mastectomy. Removing the opposite breast (prophylactic mastectomy) usually isn't recommended; chemotherapy usually isn't recommended either. Hormonal therapy may be recommended if the DCIS is hormone-receptor-positive.
Nearly 1,200 women 40 or older diagnosed with DCIS between 1983 and 1994 participated in the study. All the women had lumpectomy and none got radiation therapy after surgery. The researchers noted how the DCIS was diagnosed (mammogram or palpation) and tested the DCIS cells for a number of biomarkers. Half the women were followed for more than 8 years and half were followed for shorter periods of time.
During the follow-up period, 14.6% of the women were diagnosed with invasive breast cancer in the same breast and 13.3% were diagnosed with a second DCIS.
Developing invasive breast cancer in the 8 years after DCIS diagnosis was:
- twice as likely if the DCIS cells tested positive for the biomarkers p16, COX-2, and Ki67 compared to DCIS cells that didn't test positive for these biomarkers
- 27.3% of the women diagnosed with DCIS that tested positive for these three biomarkers developed invasive breast cancer compared to 9.5% of women with DCIS that tested negative for these three biomarkers
- three times as likely in women with DCIS diagnosed by palpation compared to women with DCIS diagnosed by mammogram
There also seem to be links between certain biomarkers and higher risk of being diagnosed with a second DCIS.
If you've been diagnosed with DCIS, you and your doctor will have several treatment decisions to make:
- Lumpectomy or prophylactic mastectomy: Some women will choose to have one or both breasts removed to minimize their risk of a future invasive breast cancer. To achieve a balanced appearance, some women may choose to have a double mastectomy and reconstruct both breasts at the same time.
- Radiation therapy after surgery: Radiation is often but not always done after DCIS surgery. Radiation is ideally used only in women most likely to benefit from it.
- Hormonal therapy after surgery: If the DCIS is hormone-receptor-positive, your doctor may recommend hormonal therapy -- tamoxifen or an aromatase inhibitor -- after surgery to reduce the risk of being diagnosed with invasive breast cancer in the future. Hormonal therapy is ideally used only in women most likely to benefit from it.
A better way to calculate a woman's risk of future invasive breast cancer after DCIS, which would help plan DCIS treatment, would be a good tool to have. While this study is promising, it's very preliminary and more research is needed to better understand how reliable the link between DCIS biomarkers and the risk of future invasive breast cancer is.
If you've been diagnosed with DCIS, you and your doctor will consider the details of the cancer (which might include biomarker information) and your specific situation when deciding on a treatment plan. You may want to ask your doctor about your future risk and the factors used to figure out that risk. As you consider DCIS treatment options, make sure to tell your doctor about your preferences (lumpectomy versus mastectomy, for example) and any specific concerns you have. Together, you can choose a plan that makes the most sense for you and your unique situation.
Visit the Breastcancer.org DCIS pages to learn more about DCIS and how it's treated.