Abstract
BACKGROUND: The incidence of ductal carcinoma in situ (DCIS) has increased markedly in recent decades. In the past, mastectomy was the primary treatment for patients with DCIS, but as with invasive cancer, breast-conserving surgery followed by radiation therapy (RT) has become the standard approach. We present the final results of a multi-institutional retrospective study of an Italian Radiation Oncology Group for the study of conservative treatment of DCIS, characterized by a very long period of accrual, from February 1985 to March 2000, and a median follow-up longer than 11 years. METHODS: A collaborative multi-institutional study was conducted in Italy in 10 Radiation Oncology Departments. A consecutive series of 586 women with DCIS histologically confirmed, treated between February 1985 and March 2000, was retrospectively evaluated. Median age at diagnosis was 55 years (range: 29-84); 32 patients were 40 years old or younger. All women underwent conservative surgery followed by whole breast RT. Irradiation was delivered to the entire breast, for a median total dose of 50 Gy; the tumour bed was boosted in 295 cases (50%) at a median dose of 10 Gy. RESULTS: After a median follow-up of 136 months (range: 16-292 months), 59/586 patients (10%) experienced a local recurrence: invasive in 37 cases, intraductal in 20 and not specified in two. Salvage mastectomy was the treatment of choice in 46 recurrent patients; conservative surgery in 10 and it was unknown in three patients. The incidence of local recurrence was significantly higher in women younger than 40 years (31.3%) (p= 0.0009). Five patients developed distant metastases. Furthermore 40 patients developed a contralateral breast cancer and 31 a second primary tumour in a different site. The 10-year actuarial overall survival (OS) was 95.5% and the 10-year actuarial disease-specific survival (DSS) was 99%. CONCLUSIONS: Our results are consistent with those reported in the literature. In particular it has been defined the importance of young age (40 years or less) as a relevant risk factor for local recurrence. This retrospective multi-institutional Italian study confirms the long term efficacy of breast conserving surgery with RT in women with DCIS.