Ductal carcinoma in situ of the breast in Singapore: Recent trends and clinical implications

BACKGROUND: Breast ductal carcinoma in-situ (DCIS) is increasingly being diagnosed as a result of screening mammography and better pathological recognition. With this and the rising breast cancer incidence in Singapore, DCIS is poised to become a bigger part of surgical practice. Principles of screening, diagnosis and management of DCIS have also been rapidly evolving. Against this background, a clinicopathological audit of recent cases of DCIS in our centre was performed. METHODS: Thirty-eight cases of DCIS diagnosed in the period 1997-2000 were retrospectively analysed. Histological examination and immunohistochemical studies for oestrogen and progesterone receptor expression were performed. RESULTS: In the present study, DCIS was most common in the group of patients who were <50 years (58%) as compared to an American series' where the corresponding group were > or =60 years (36%). Compared to a previous local study a decade ago, the present series showed that: (i) DCIS constituted a higher proportion of all breast cancers (6.4% vs 3.7%); (ii) a larger proportion of patients had disease detected by mammography (47% vs 10%); (iii) conservative breast excision was the only definitive surgery in 39% of cases (vs approximately 30%); and (iv) the mean size of lesions is smaller (13.5 mm vs 24.4 mm). Histologically, 26% of tumours were high grade, 71% had necrosis while 32% were oestrogen receptor (ER) and progesterone receptor (PR) negative. High grade tumours were associated with the presence of necrosis (P = 0.018), ER negativity (P = 0.015) and PR negativity (P = 0.001). CONCLUSIONS: This study reveals interesting trends of DCIS in Singapore. The sizeable proportion of hormone receptor-negative tumours may have implications for the hormonal adjuvant therapy of DCIS.