Breast cancer stromal elastosis is associated with mammography screening detection, low Ki67 expression and favourable prognosis in a population-based study.

Ying Chen,Tor A Klingen,Einar Vigeland,Knut Liestøl,Elisabeth Wik,Øystein Garred,Lars A Akslen,Jan Mæhlen,Jon Lømo,Hans Aas

doi:10.1186/s13000-014-0230-8

Abstract

BackgroundMammography screen-detected breast cancers have a better prognosis than predicted from established prognostic markers. A search for additional features that are characteristic for these tumours and their prognosis is needed to reduce overtreatment, a recognized challenge in breast cancer patient management today. Here, we have investigated the occurrence and importance of tumour elastosis.MethodsWe performed a population based retrospective study of breast cancers detected in the Norwegian Breast Cancer Screening Programme in Vestfold County during 2004–2009. In total, 197 invasive screen-detected cancers and 75 interval cancers in patients aged 50–69 years were compared with regard to standard clinico-pathological parameters and tumour shape, as well as ER, PR, HER2 and Ki67 expression. In particular, the presence of elastotic material in tumours was graded on a 4-tiered scale (score 0–3).ResultsScreen-detected cancers had a significantly higher content of stromal elastosis than interval cancers (p < 0.001). High content of elastosis (score 3) correlated strongly with stellate tumour shape, low histological grade, and ER+/HER2- status. Further, high elastosis score was significantly associated with lower Ki67 expression. In survival analyses, cases with high elastosis demonstrated increased recurrence free (p = 0.03) and disease-specific survival (p = 0.11) compared to cases with low elastosis.ConclusionThere is a strong correlation between the presence of tumour elastosis, stellate tumour shape and mammography detection of breast cancers. To our knowledge, this is the first time elastosis has been studied in relation to breast cancer detection method. Presence of elastosis is associated with low tumour cell proliferation (Ki67) and a good prognosis.Virtual SlidesThe virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_230

Highlights

Mammography screen-detected breast cancers have a better prognosis than predicted from established prognostic markers
Follow-up studies from different countries indicate that screen-detected cancers have more low-grade features and better outcome than predicted from tumour size, histological grade, and lymph node status included in the Nottingham Prognostic Index [7,8]
The aim of our study was to establish whether there is a significant difference in elastosis content between screen detected and interval breast cancers, and whether elastosis is a marker of cancers detected by mammography and a possible mediator of their good prognosis

Summary

Introduction

Mammography screen-detected breast cancers have a better prognosis than predicted from established prognostic markers. A search for additional features that are characteristic for these tumours and their prognosis is needed to reduce overtreatment, a recognized challenge in breast cancer patient management today. The introduction of mammography screening for breast cancer has been associated with up to 50% incidence increase in invited age groups [3,4,5] Both tumour size and other prognostic factors are more favourable for screened cancers than for symptomatic (non-screened) tumours [6]. A search for additional histological or molecular characteristics of screen-detected cancers with an especially favourable prognosis is needed. Their identification could result in less overtreatment, which is a known challenge in breast cancer patient management today [13]

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