Treatment of ductal carcinoma in situ of the breast: results from a monoinstitutional cohort of 1308 women Free

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Background Detection rate of ductal carcinoma in situ (DCIS) of the breast has increased in the last twenty years, however the most appropriate post-surgical treatment is debated. Radiotherapy (RT) has shown to significantly reduce breast cancer (BC) recurrence and tamoxifen therapy has shown to be beneficial in estrogen receptor (ER) positive BC only, but the heterogeneity of the disease may impact the outcome. Given the positive results of phase II clinical trials conducted within the European Institute of Oncology, low dose tamoxifen in ER positive DCIS currently represents an alternative to standard dose as an internal guideline if no clinical trial option is available.
 >Methods Evaluation of all women undergoing surgery for a breast DCIS at the European Institute of Oncology between 1996 and 2005 and having a follow-up as of December 31, 2006.
 >Results A total of 1308 women have been included. After a median follow-up of 40 months, 126 local, regional or distant events occurred and the five-year cumulative incidence was 43, 23, 13, 9 and 8, for women aged <35, 36-40, 41-50, 51-65 and >65 years, respectively. Only 1 patient died for breast cancer. RT was not offered to G1 DCIS patients. Overall, hazard ratio (HR) for G2-G3 DCIS alone vs G2-G3+RT was 2.5 (95% CI 1.6-3.9) irrespective of ER status and preventive treatment. In ER positive DCIS with breast conserving surgery, HR for no hormonal treatment vs treatment (almost always low dose tamoxifen) was 1.5 (95% CI 0.93-2.3). A statistically significant reduction of recurrence has been observed in DCIS not overexpressing Her2/neu treated with low dose tamoxifen (HR 1.8, 95% CI 1.03-3.01).
 >Conclusions Younger age represents the worst prognostic factors both for in situ and invasive recurrence. RT lowers BC recurrence by 2.5 fold in G2-G3 DCIS. Low dose tamoxifen confirms its ability to reduce BC recurrence and is more effective in DCIS not overexpressing Her2/neu. A phase III trial is warranted to determine the most appropriate population that may benefit of low dose tamoxifen.