Renaming Ductal Carcinoma in Situ: Would Removing “Carcinoma” Reduce Overtreatment?

Abstract

In both the medical literature and lay press, a flurry of controversy has arisen surrounding the treatment and, more specifically, the potential overtreatment of ductal carcinoma in situ (DCIS). Since the advent of population-based screening mammography in the mid-1980s, the incidence of DCIS has increased more than 8-fold, with DCIS now accounting for nearly 22% of new breast cancer diagnoses.1,2 Since 1990, death rates from breast cancer in the United States have decreased by approximately 34%,1,3 a favorable outcome that has been attributed to the combination of increased screening mammography and improved adjuvant therapy.4 However, despite the steady increase in DCIS detection and treatment in the 1990s, the subsequent incidence of invasive breast cancers did not proportionately decrease.5 Invasive breast cancer incidence among women older than 50 years declined sharply between 2002 and 2003 but has since stabilized, a finding that could reflect a reduced pool of prevalent breast cancer cases as a result of widespread screening, but also could relate to the decreased use of hormone replacement therapy or trends in mammography screening rates that peaked in 2000.1 Approximately 1 in every 1300 screening mammography examinations leads to a diagnosis of DCIS, of which up to 30% will be treated with mastectomy.6,7 Several recent publications suggest the possibility that, although implementation of routine screening mammography has led to an overall increase in breast cancer detection and has been associated with a decrease in overall breast cancer mortality, it has not produced the magnitude of reduction in advanced-stage cancers one would expect based on detection of breast cancer at its nascent stage, namely DCIS.8 DCIS can be defined, to patients and providers alike, as noninvasive, preinvasive, a precursor to, stage 0, or, quite simply, what most patients hear at the end of such a preface: breast cancer. This dilemma in terminology has led to heated discourse at national breast specialty meetings and to front-page cover stories in The New York Times, and is an important issue to the growing constituency of breast cancer survivors who drive breast cancer awareness in this country.9 DCIS is a non–life-threatening, atypical intraductal proliferation that, if left untreated, can progress to invasive breast cancer. However, DCIS progression is not obligatory and not inevitable. Sanders et al10 showed that a significant fraction of DCIS cases will not progress to clinically apparent invasive disease. They examined the incidence of invasive breast cancer among a large cohort of patients originally diagnosed in the 1950s and 1960s as having benign breast pathology but who, on retrospective review were found to have low-grade DCIS. Of those with DCIS, only 40% subsequently developed an invasive breast cancer in the same quadrant of the same breast, most of which occurred within 10 years. Other studies, including population-based modeling experiments, have examined the natural history of low-grade DCIS and suggest that as few as 20% of cases might progress to invasive cancer over a protracted period spanning from 5 to 40 years.5 In the absence of progression to invasive cancer, overall survival after a diagnosis of DCIS is upwards of 98%. The goal of treatment is solely to prevent either local recurrence or progression to invasive breast cancer. Based on data from 4 randomized clinical trials, local treatment options for patients with DCIS currently include either breast-conserving surgery followed by radiation therapy, or mastectomy.11–14 Tamoxifen is also considered as possible adjuvant therapy for patients with estrogen receptor–positive DCIS, both for reduction of local recurrence risk after breastSara H. Javid, MD