Histological grade provides significant prognostic information in addition to breast cancer subtypes defined according to St Gallen 2013.

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 (≥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.

• Authors: Anna Ehinger, Per Malmström, Pär-Ola Bendahl, Christopher W Elston, Anna-Karin Falck, Carina Forsare, Dorthe Grabau, Lisa Rydén, Olle Stål, Mårten Fernö, South and South-East Swedish Breast Cancer Groups
• Journal: Acta oncologica (Stockholm, Sweden) (Acta Oncol) Vol. 56 Issue 1 Pg. 68-74 (Jan 2017) ISSN: 1651-226X [Electronic] England
• PMID: 27762648 (Publication Type: Journal Article, Multicenter Study, Randomized Controlled Trial)

Chemical References

• Biomarkers, Tumor
• Receptors, Estrogen
• Receptors, Progesterone
• Receptor, ErbB-2

Topics

• Adult
• Aged
• Aged, 80 and over
• Antineoplastic Combined Chemotherapy Protocols (therapeutic use)
• Biomarkers, Tumor (metabolism)
• Breast Neoplasms (classification, drug therapy, metabolism, pathology)
• Cohort Studies
• Female
• Follow-Up Studies
• Humans
• Immunoenzyme Techniques
• Lymphatic Metastasis
• Middle Aged
• Neoplasm Grading
• Neoplasm Recurrence, Local (drug therapy, metabolism, pathology)
• Neoplasm Staging
• Prognosis
• Receptor, ErbB-2 (metabolism)
• Receptors, Estrogen (metabolism)
• Receptors, Progesterone (metabolism)
• Survival Rate