Subclinical ductal carcinoma in situ of the breast: Treatment with conservative surgery and radiotherapy

Aims and background: In spite of the fact that ductal carcinoma in situ (DC IS) of the breast is a frequently encountered clinical problem, there is no consensus about the optimal treatment of clinically occult (i.e., mammogra phic presentation only) DCIS. Interest in breast conservation therapy has r ecently increased. Few data are available in Italy on the conservative trea tment with surgery and adjuvant postoperative radiotherapy. Methods: A retrospective multi-institutional study was performed in 15 Radi ation Oncology Departments in northern Italy involving 112 women with subcl inical DCIS of the breast treated between 1982 and 1993, Age of the patient s ranged between 32 and 72 years (median, 50 years). All of them underwent conservative surgery: quadrantectomy in 89, tumorectomy in 11, and wide exc ision in 12 cases. The most common histologic subtype was comedocarcinoma ( 37%), The median pathologic size was 10 mm (range 1 to 55 mm). Axillary dis section was performed in 83 cases: all the patients were node negative. All the patients received adjunctive radiation therapy with Co-60 units (77%) or 6 MV linear accelerators (23%) for a median total dose to the entire bre ast of 50 Gy (mean, 49.48 Gy; range, 45-60 Gy). Seventy-six cases (68%) rec eived a boost to the tumor bed at a dose of 8-20 Gy (median 10 Gy) for a mi nimum tumor dose of 58 Gy. Results: At a median follow-up of 66 months, 8 local recurrences were obser ved, 4 intraductal and 4 invasive. All recurrent patients had a salvage mas tectomy and are alive and free of disease at this writing. The 10-year actu arial overall, cause-specific, and recurrence-free survival was of 98.8%, 1 00%, and 91%, respectively. Conclusions: The retrospective multicentric study, with a local control rat e of more than 90% at 10 years with 100% cause-specific survival, showed th at conservative surgery and adjuvant radiation therapy is a safe and effica cious treatment for patients with occult, non-palpable DCIS.