Treatment of non-invasive (stage 0) breast cancer

Treatment of non-invasive (stage 0) breast cancer

Stage 0 includes lobular carcinoma in situ (LCIS) and ductal carcinoma in situ (DCIS),
which are treated very differently.
LCIS: Since this is not a true cancer or pre-cancer, no immediate or active treatment is
recommended for most women with LCIS. But because having LCIS increases your risk
of developing invasive cancer later on, close follow-up is very important. This usually
includes a yearly mammogram and a clinical breast exam. Close follow-up of both
breasts is important because women with LCIS in one breast have the same increased risk
of developing cancer in either breast. Although there is not enough evidence to
recommend routine use of magnetic resonance imaging (MRI) in addition to
mammograms for women with LCIS, it is reasonable for these women to talk with their
doctors about the benefits and limits of being screened yearly with MRI.
Women with LCIS may also want to consider taking tamoxifen or raloxifene to reduce
their risk of breast cancer or taking part in a clinical trial for breast cancer prevention. For
more information on drugs to reduce breast cancer risk see our document, Medicines to
Reduce Breast Cancer Risk. They might also wish to discuss other possible prevention
strategies (such as reaching an optimal body weight or starting an exercise program) with
their doctor.
Some women with LCIS choose to have a bilateral simple mastectomy (removal of both
breasts but not axillary lymph nodes) to reduce their risk of breast cancer, especially if
they have other risk factors, such as a strong family history. Depending on the woman's
preference, she may consider immediate or delayed breast reconstruction.
DCIS: In most cases, a woman with DCIS can choose between breast-conserving surgery
(BCS) and simple mastectomy. BCS is usually followed by radiation therapy. Lymph
node removal (most often a sentinel lymph node biopsy) is not always needed. It may be
done if the doctor thinks that a woman with DCIS may also have an area of invasive
cancer. The risk of an area of DCIS containing invasive cancer goes up with tumor size
and nuclear grade. Many doctors will do a sentinel lymph node biopsy if a mastectomy is
done. This is because if an area of invasive cancer is found in the tissue removed during a
mastectomy, the doctor won’t be able to go back and do a sentinel lymph node procedure
later, and so may have to do a full axillary lymph node dissection.
Radiation therapy given after BCS lowers the chance of the cancer coming back in the
same breast (as more DCIS or as an invasive cancer). BCS without radiation therapy is
not a standard treatment, but might be an option for certain women who had small areas
of low-grade DCIS that was removed with large enough cancer-free surgical margins.
But most women who have BCS for DCIS will require radiation therapy.
Mastectomy may be necessary if the area of DCIS is very large, if the breast has several
areas of DCIS, or if BCS cannot completely remove the DCIS (that is, the BCS specimen
and re-excision specimens have cancer cells in or near the surgical margins). Women
having a mastectomy for DCIS may have reconstruction immediately or later.
If the DCIS is estrogen receptor−positive, treatment with tamoxifen for 5 years after
surgery can lower the risk of another DCIS or invasive cancer developing in either breast.
Women may want to discuss the pros and cons of this option with their doctors.