Controversies in the Treatment of Ductal Carcinoma in Situ

Ductal carcinoma in situ (DCIS) accounts for 20% of all newly diagnosed breast cancers. Mastectomy was once the gold standard for the treatment of DCIS; however, breast-conserving surgery (BCS) has been adopted as the treatment of choice for patients with small, screen-detected lesions. Both adjuvant radiation and hormonal therapy following BCS have been demonstrated in randomized trials to reduce the risk of both invasive and DCIS recurrence, but neither affects survival. With the variety of surgical and adjuvant treatment options available, there has been great interest in tailoring the treatment to the individual, with the goal of optimizing the balance of risks and benefits according to the values and priorities of the woman herself. Prospective studies of women with "low-risk" DCIS treated with BCS alone have successfully identified women at lower than average risk but have not achieved the goal of identifying a subset of women with DCIS at minimal risk of recurrence after surgical excision alone. No studies have evaluated the safety of medical management alone.

Stromal architecture and periductal decorin are potential prognostic markers for ipsilateral locoregional recurrence in ductal carcinoma in situ of the breast

AIMS

The incidence of ductal carcinoma in situ (DCIS) has increased since the introduction of screening mammography. Recurrence prediction is still not accurate, and could be improved by identifying additional prognostic markers. Periductal stroma actively participates in early breast cancer progression. Therefore, the aim of this study was to explore the prognostic potential of stromal characteristics in DCIS.

METHODS AND RESULTS

Histopathological features and hormone receptor/HER2 status were analysed in a first cohort of 65 cases of DCIS with a median follow-up of 112 months. Cox regression analysis revealed that myxoid stromal architecture was significantly associated with increased ipsilateral locoregional recurrence (P = 0.015). Next, we performed immunohistochemical screening of nine stromal proteins in a second cohort of 82 DCIS cases, and correlated their expression with stromal architecture. Because reduced stromal decorin expression correlated most strongly with myxoid stroma (P < 0.001), it was selected for further analysis in the first cohort. Patients with reduced periductal decorin expression had a higher risk of recurrence (P = 0.008). Furthermore, HER2 overexpression was significantly associated with invasive but not with in situ recurrence (P = 0.007).

CONCLUSIONS

Periductal myxoid stroma and reduced periductal decorin expression seem to be prognostic for overall ipsilateral locoregional recurrence in DCIS, whereas HER2 expression might be a more specific biomarker for invasive recurrence.