Long-Term Survival of Breast Ductal Carcinoma In Situ in Women with Different Gene-Expression Types.

Abstract

Abstract Background: Basal-like invasive breast cancer has been shown to be associated with a worse prognosis. However, we do not know if basal-like ductal carcinoma in situ (DCIS) relates to a worse prognosis. The purpose of this study was to relate the DCIS basal-like subgroup, evaluated by immunohistochemistry (IHC), with prognosis.Material and Methods: Women diagnosed with a primary DCIS 1986-2004 in Uppsala and Västerås, Sweden were recruited (n=458). TMA blocks were constructed and IHC for Estrogen receptor (ER), Her2, epidermal growth factor receptor (EGFR/Her1) and cytokeratin 5/6 (CK 5/6) was employed to evaluate the gene-expression subgroups. Subtype definitions were as follows: luminal A (ER+ and HER2–), luminal B (ER+ and HER2+), basal-like (ER–, HER2–, CK 5/6+ and/or EGFR+), HER2+ (ER– and HER2+), and others (negative for all markers or data missing).Results: We followed 458 patients for local recurrence, general disease and all-causes mortality. Median follow-up was 122 months. Of the 458 primary DCIS breast cancers, 224 (48.9%) were luminal A subtype, 63 (13.8%) were luminal B, 80 (17.5%) were Her2+, 29 (6.3%) basal-like and 62 (13.5%) unclassified. Local recurrence and general disease rates were similar when comparing basal-like group with each of the other four groups. Compared with the most common luminal A tumors, basal-like tumors were related with poorer survival (hazard ratio 2.56, 95% confidence interval 1.05 – 6.22). When compared with luminal B, Her2+ and unclassified group, basal-like tumors were related with non-significant poorer survival, with a HR (95% CI) of 1.37 (0.52 – 3.64), 1.80 (0.69 – 4.72) and 2.61 (0.61 – 11.2), respectively. We also compared basal-like group with the rest combined as one non-basal-like group. Local recurrence and general disease rates were similar in these two groups. Women with basal-like DCIS had higher mortality than women in the non-basal-like group (HR 2.26, 95% CI 1.00 - 5.10).Conclusion: Basal-like DCIS women may have poorer overall survival, particularly in comparison with luminal A DCIS. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2114.