Prognostic factors in phyllodes tumours of the breast: retrospective study on 166 consecutive cases.

Abstract

BACKGROUND:

Phyllodes tumours (PTs) are rare fibroepithelial tumours accounting for <1% of all breast tumours. We assessed clinicopathological features and their prognostic effect in a single-institution patients' cohort.

METHODS:

Patients diagnosed with PT between 2001 and 2018 at our institution were identified. Clinical, surgical and pathological features were collected. Phyllodes-related relapse was defined as locoregional or distant recurrence (contralateral excluded), whichever first.

RESULTS:

A total of 166 patients were included: 115 with benign, 30 with borderline and 21 with malignant PTs. Features associated with malignant PT were younger age, larger T size, higher mitotic count, marked cytological atypia, stromal overgrowth, stromal hypercellularity, necrosis and heterologous differentiation (all p<0.01). The majority of patients with malignant PT underwent mastectomy (63.2% vs 3% of benign/borderline, p<0.001) and had negative surgical margins (83.3%). 4-year cumulative phyllodes-related relapse incidence was 7% for benign/borderline PT and 21.3% for malignant PT (p=0.107). In the entire cohort, marked cellular atypia and heterologous differentiation were associated with worse phyllodes-related relapse-free survival (HR 14.10, p=0.036 for marked vs mild atypia; HR 4.21, p=0.031 for heterologous differentiation present vs absent). For patients with benign PT, larger tumour size was associated with worse phyllodes-related relapse-free survival (HR 9.67, p=0.013 for T>5 cm vs T≤2 cm). Higher tumour-infiltrating lymphocytes (TILs) were associated with borderline and malignant PT (p=0.023); TILs were not associated with phyllodes-related relapse-free survival (HR 0.58, p=0.361 for TILs>2% vs≤2%). Overall, four patients died because of PT: three patients with malignant and one with borderline PT.

CONCLUSIONS:

Patients with malignant PT had increased rates of phyllodes-related relapse and phyllodes-related death. Cellular atypia and heterologous differentiation were poor prognostic factors in the entire cohort; large tumour size was associated with an increased risk of phyllodes-related relapse in benign PT.

• Authors: Elisabetta Di Liso, Michele Bottosso, Marcello Lo Mele, Vassilena Tsvetkova, Maria Vittoria Dieci, Federica Miglietta, Cristina Falci, Giovanni Faggioni, Giulia Tasca, Carlo Alberto Giorgi, Tommaso Giarratano, Eleonora Mioranza, Silvia Michieletto, Tania Saibene, Angelo Paolo Dei Tos, PierFranco Conte, Valentina Guarneri
• Journal: ESMO open (ESMO Open) Vol. 5 Issue 5 Pg. e000843 (10 2020) ISSN: 2059-7029 [Electronic] England
• PMID: 33020219 (Publication Type: Journal Article)
• Copyright: © Author (s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. Published by BMJ on behalf of the European Society for Medical Oncology.

Topics

• Breast Neoplasms (diagnosis, epidemiology, therapy)
• Female
• Humans
• Mastectomy
• Neoplasm Recurrence, Local (surgery)
• Phyllodes Tumor (diagnosis, surgery)
• Prognosis
• Retrospective Studies