Aims and background: In spite of the fact that ductal carcinoma in situ (DCIS) of the breast is a frequently encountered clinical problem, there is no consensus about the optimal treatment of clinically occult (i.e., mammographic presentation only) DCIS. Interest in breast conservation therapy has recently increased. Few data are available in Italy on the conservative treatment with surgery and adjuvant postoperative radiotherapy.
Methods: A retrospective multi-institutional study was performed in 15 Radiation Oncology Departments in northern Italy involving 112 women with subclinical DCIS of the breast treated between 1982 and 1993. Age of the patients ranged between 32 and 72 years (median, 50 years). All of them underwent conservative surgery: quadrantectomy in 89, tumorectomy in 11, and wide excision in 12 cases. The most common histologic subtype was comedocarcinoma (37%). The median pathologic size was 10 mm (range 1 to 55 mm). Axillary dissection was performed in 83 cases: all the patients were node negative. All the patients received adjunctive radiation therapy with 60Co units (77%) or 6 MV linear accelerators (23%) for a median total dose to the entire breast of 50 Gy (mean, 49.48 Gy; range, 45-60 Gy). Seventy-six cases (68%) received a boost to the tumor bed at a dose of 8-20 Gy (median 10 Gy) for a minimum tumor dose of 58 Gy.
Results: At a median follow-up of 66 months, 8 local recurrences were observed, 4 intraductal and 4 invasive. All recurrent patients had a salvage mastectomy and are alive and free of disease at this writing. The 10-year actuarial overall, cause-specific, and recurrence-free survival was of 98.8%, 100%, and 91%, respectively.
Conclusions: The retrospective multicentric study, with a local control rate of more than 90% at 10 years with 100% cause-specific survival, showed that conservative surgery and adjuvant radiation therapy is a safe and efficacious treatment for patients with occult, non-palpable DCIS.