We reviewed the records of patients with DCIS treated between 1987 and 2000, carried out a pathology review and immunohistochemical staining for ER, PR and HER2neu and categorised cases into four molecular phenotypes [luminal A (ER+ and/or PR+, HER2neu-), luminal B (ER+ and/or PR+, HER2neu+), HER2neu subtype (ER-, PR-, HER2neu+), triple negative (ER-, PR-, HER2neu-)]. We evaluated the association between the molecular subtype and the development of local recurrence.
In total, 180 cases of DCIS were included in the study (luminal A, n = 113; luminal B, n = 25; HER2neu type, n = 29; triple negative, n = 13). The median follow-up time was 8.7 years. We observed higher rates of local recurrence among luminal B (40%) and HER2neu type (38%) DCIS compared with luminal A (21%) and triple negative (15%) DCIS. On multivariable analysis, HER2neu overexpression was associated with an increased risk of local recurrence (hazard ratio = 1.98; 95%confidence interval: 1.11, 3.53, P = 0.02).
HER2neu expression in DCIS is a significant predictor of local recurrence, whereas luminal A and triple negative phenotypes are associated with relatively low risks of local recurrence.