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- Ehinger, Anna, et al.
(author)
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Histological grade provides significant prognostic information in addition to breast cancer subtypes defined according to St Gallen 2013
- 2017
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In: Acta Oncologica. - : TAYLOR & FRANCIS LTD. - 0284-186X .- 1651-226X. ; 56:1, s. 68-74
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Journal article (peer-reviewed)abstract
- Background: The St Gallen surrogate definition of the intrinsic subtypes of breast cancer consist of five subgroups based on estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor type 2 (HER2), and Ki-67. PgR and Ki-67 are used for discriminating between the Luminal A-like and Luminal B-like (HER2-negative) subtypes. Histological grade (G) has prognostic value in breast cancer; however, its relationship to the St Gallen subtypes is not clear. Based on a previous pilot study, we hypothesized that G could be a primary discriminator for ER-positive/HER2-negative breast cancers that were G1 or G3, whereas Ki-67 and PgR could provide additional prognostic information specifically for patients with G2 tumors. To test this hypothesis, a larger patient cohort was examined. Patients and methods: Six hundred seventy-one patients (amp;gt;= 35 years of age, pT1-2, pN0-1) with ER-positive/HER2-negative breast cancer and complete data for PgR, Ki-67, G, lymph node status, tumor size, age, and distant disease-free survival (DDFS; median follow-up 9.2 years) were included. Results: Luminal A-like tumors were mostly G1 or G2 (90%) whereas Luminal B-like tumors were mostly G2 or G3 (87%) and corresponded with good and poor DDFS, respectively. In Luminal B-like tumors that were G1 (n = 23), no metastasis occurred, whereas 14 of 40 Luminal A-like tumors that were G3 metastasized. In the G2 subgroup, low PgR and high Ki-67 were associated with an increased risk of distant metastases, hazard ratio (HR) and 95% confidence interval (CI) 1.8 (0.95-3.4) and 1.5 (0.80-2.8), respectively. Conclusions: Patients with ER-positive/HER2-negative/G1 breast cancer have a good prognosis, similar to that of Luminal A-like, while those with ER-positive/HER2-negative/G3 breast cancer have a worse prognosis, similar to that of Luminal B-like, when assessed independently of PgR and Ki-67. Therapy decisions based on Ki-67 and PgR might thus be restricted to the subgroup G2.
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