As many as 60,000 American women each year are told they have a very early stage of breast cancer — Stage 0, as it is commonly known — a possible precursor to what could be a deadly tumor. And almost every one of the women has either a lumpectomy or a mastectomy, and often a double mastectomy, removing a healthy breast as well.
Yet it now appears that treatment may make no difference in their outcomes. Patients with this condition had close to the same likelihood of dying of breast cancer as women in the general population, and the few who died did so despite treatment, not for lack of it, researchers reported Thursday in JAMA Oncology.
Their conclusions were based on the most extensive collection of data ever analyzed on the condition, known as ductal carcinoma in situ, or D.C.I.S.: 100,000 women followed for 20 years. The findings are likely to fan debate about whether tens of thousands of patients are undergoing unnecessary and sometimes disfiguring treatments for premalignant conditions that are unlikely to develop into life-threatening cancers.