Ductal carcinoma in situ of the breast results of conservative and radical treatments in 716 patients

Abstract

Until now, less than 5% of the patients with breast ductal carcinoma in situ (DCIS) have been enrolled in clinical trials. Consequently, we have analysed the results of ‘current practice’ among 716 women treated in eight French Cancer Centres from 1985 to 1992: 441 cases (61.6%) corresponded to impalpable lesions, 92 had a clinical size of less than or equal to 2 cm and 70 from 2 to 5 cm; in 113 cases, the size was unspecified. Median age was 53.2 years (range: 21–87 years). 145 patients underwent mastectomy (RS) and 571 conservative surgery (CS) without (136) or with (435) radiotherapy (CS+RT). The mean histological tumour sizes in these three groups were 25.6, 8.2, 14.8 mm, respectively (P<0.0001). After a 91-month median follow-up, local recurrence (LR) rates were 2.1, 30.1 and 13.8% in the RS, CS and CS +RT groups, respectively (P=0.001); LR were invasive in 59 and 60% in the CS and CS+RT groups, respectively. In these groups, the 8-year LR rates were 31.3 and 13.9%, respectively (P=0.0001). Nodal recurrence occurred in 3.7 and 1.8% in the CS and CS+RT groups. Metastases rates were 1.4, 4.4 and 1.4% in the RS, CS and CS+RT groups. Among the 60 cases of invasive LR, in CS and CS+RT groups 19% developed metastases. After multivariate analysis, we did not identify any significant LR risk factor in the CS group, whereas young age (<40years) and incomplete excision were significant in the CS+RT group (P=0.012 and P=0.02, respectively).

Introduction

With the increasing use of mammography, ductal carcinoma in situ (DCIS) has become a more common diagnosis. Estimates for the next decade are that DCIS will form approximately 20% of all breast cancers 1, 2. For years, mastectomy was the standard treatment with an almost 100% cure rate.

Many centres now use breast conserving surgery, alone (CS) or with radiotherapy (CS+RT), for selected cases of DCIS 3, 4, 5 but results in term of local recurrence (LR) vary widely. This may be explained by heterogeneity in the inclusion criteria, therapeutic modalities, histological procedures, methods of detection and follow-up duration.

Until now, two randomised trials have confirmed that radiation therapy (RT) decreases the rates of LR of invasive and non-invasive disease in DCIS treated conservatively 6, 7, 8, 9. However, the patients included in these trials form less than 5% of all DCIS treated in the same period and it is still doubtful whether to use RT in all cases, such as those particularly outlined in the Van Nuys team's paper [10].

We describe herein a retrospective analysis of the treatments used and outcomes in DCIS in eight French Cancer Centres between January 1985 and December 1992.