Ductal carcinoma in situ (DCIS) treated by mastectomy, or local excision with or without radiotherapy: A monocentric, retrospective study of 608 women.

Objectives: Since mammographic screening programmes, the proportion of DCIS has dramatically increased. Adjuvant radiotherapy (RT) after local excision (LE) has become a solid option for DCIS since 4 randomised trials have proven a decrease in local relapse (LR), though failing to prove a benefit on mortality rate. DCIS is a heterogeneous disease and it is unclear whether all patients uniformly benefit from radiotherapy. We report a descriptive analysis including all types of treatment.

Materials And Methods: Our retrospective cohort describes 608 women treated for DCIS in our centre between 1983 and 2013. Mastectomy was recommended before 1992, or for multifocal or >3 cm DCIS. LE alone was an option for DCIS ≤10 mm, with low or intermediate grade, and clear margins (≥2 mm). LE + RT was recommended for all other cases.

Results: The median follow-up time was 6.7 years. Treatment consisted in mastectomy for 252 women, LE + RT for 269 and LE for 86. The major prognosis factor for LR rate was the type of treatment: LE + RT or LE was associated with a higher LR-rate than those treated by mastectomy (HR respectively 2.06; 95%CI 1.33-3.19; p = 0.001 and 2.12; 95%CI 1.20-3.65; p = 0.007). In our selected population, women treated by LE + RT versus LE showed no significant differences in LR (HR 0.97; 95%CI 0.61-1.7; p = 0.91). The overall survival rate was 99.7% after ten years, with no differences between the treatment groups.

Conclusion: Although retrospective, our monocentric study suggests that LE alone could be an option for DCIS with good prognosis factors. Confirmation by larger randomised studies is needed.