Ductal carcinoma in situ in Chinese women undergoing opportunistic breast cancer screening

Aim Before the introduction of breast cancer screening in 1990, ductal carcinoma in situ (DCIS) was a rare disease, representing less than 2 per cent of all breast cancers in C hinese. With the availability of screening mammography, DCIS , which is believed to be the precursor of invasive breast cancers, is diagnosed with increasing frequency. In the present study, we evaluated the impact of breast cancer screening by comparing the clinicopathological differences between screen‐detected and symptomatic DCIS in the largest cohort of C hinese women. Patients and Methods Between M arch 2003 and M arch 2008, 206 C hinese women with DCIS were treated in the H ong K ong Sanatorium and Hospital Breast Care Centre. They were divided into two groups according to the mode of discovery: 87 (42 per cent) women were allocated to the screen‐detected DCIS group, and 119 (58 per cent) women were allocated to the symptomatic DCIS group. Clinical records and pathological reports were recorded prospectively in our multidisciplinary breast conference and reviewed retrospectively. Differences in demographic information, clinical data and breast cancer prognostic markers between the two groups were evaluated. Results Only 8.2 per cent of women with screen‐detected DCIS were under the age of 40, but it was not uncommon in women with symptomatic DCIS (23.7 per cent, P = 0.002). Women with screen‐detected DCIS also had a stronger family history of breast cancer (21.8 per cent), while only 8.4 per cent of women with symptomatic DCIS had a family history ( P = 0.006). The tumour size of the screen‐detected DCIS was smaller (mean and median: 21.9 mm and 15 mm, respectively) than the symptomatic DCIS (28.8 mm and 26 mm, respectively; P = 0.004). The tumour grade showed no difference ( P = 0.639) between the two groups. Women with screen‐detected DCIS were more likely to undergo breast‐conserving surgery (odds ratio = 2.185, 95 per cent confidence interval: 1.225–3.900, P = 0.008). There was no difference demonstrated in terms of oestrogen receptor (ER) ( P = 0.929) expression, progesterone receptor (PR) ( P = 0.578) expression, C ‐erb B ‐2 score ( P = 0.089), K i‐67 index ( P = 0.312) and triple negative for the ER/PR/ C ‐erb B ‐2 score ( P = 0.201). Conclusion Breast cancer screening allows for the early detection of high‐grade DCIS , which are considered more prone to develop into invasive cancer. Further studies are needed to review if mass screening will be translated into cost‐effectiveness and reduced mortality of breast cancer in H ong K ong.