Abstract P6-10-18: Phyllodes tumor of the breast, clinicopathological features and prognostics factors in a retrospective cohort with 7-year follow-up
Authors: Morante Z , Araujo J , Fuentes H , Neciosup S , Gomez H 
Published: May 2016

BACKGROUND: The phyllodes tumor of the breast is a rare neoplasm that represent less than 1% of all breast tumors and between 2.5% of fibroepithelial tumors. Often develop local recurrence and more infrequently metastatic capability. OBJECTIVE: The aim of this study was to describe clinical pathological characteristics and identify prognostics factors in terms of local recurrence-free survival (LRFS), distant metastasis-free survival (DMFS) and overall survival (OS) in patients with phyllodes tumors of the breast.

METHODS: We retrospectively analyzed 157 patients diagnosed and treated at the "Instituto Nacional de Enfermedades Neoplasicas" between January 2005 to December 2010. In order to evaluate the relationship between clinical features and histology of the tumors, the Pearson χ2 test was used. Kaplan-Meier method with Log-rank test or Breslow test (when it was applicable) was used to identify prognostic factors in terms of LRFS, DMFS and OS. RESULTS: The median age was 42 years (range: 13-81 years), 98 (62.4%) cases ≤ 45 years and 59 (37.6%) cases &gt; 45 years; 88 (56.1%) had tumors in the right breast, 67 (42.7%) in the left breast and 2 (1.3%) had bilateral tumor. The mean of tumor size was 6.3 cm (range: 0.7-30 cm). Sixty three (40%) tumors were ≤5 cm and 94 (59.9%) were &gt;5cm. Regarding the histological classification, 100 (63.7%) cases were benign, 35 (22.3%) were borderline and 22 (14%) were malignant. Age (p=0.047), tumor size (p=0.001), atypical stromal (p=0.066), stromal cellularity (p&lt;0.001), pleomorphism (p&lt;0.001) and tumor necrosis (p=0.003) were associated to the histological type. Local recurrence occurred in 9 patients, 2 developed distant recurrence and 1 patient presented synchronously local and metastatic recurrence. In the univariate analysis, histological subtype (p=0.006) and pleomorphism (p&lt;0.001) were identified as prognostic factors of LRFS, while the surgical approach (p=0.008), histological type (p&lt;0.001) and some histological features such as stromal cellularity (P&lt;0.001), pleomorphism (p&lt;0.001), heterologous elements (p&lt;0.001) and tumor necrosis (p=0.004) were identified as prognostic factors for DMFS. In regard to the OS, we found as prognosis factors, histology (p= 0.044), pleomorphism (p&lt;0.001) and tumor necrosis (p=0.001).

CONCLUSIONS: In our institution we have a low incidence (2.3%) of Phyllodes tumors of the breast and the majority of our patients were benign tumors and had good prognosis. We found that histological type and degree of pleomorphism are prognostic factors at LRFS and OS. Surgical approach, histological type and some histological characteristics were predictors for DMFS.

Keywords: Phyllodes tumor, local recurrence, distant recurrence, overall survival.

Citation Format: Morante Z, Araujo J, Fuentes H, Neciosup S, Gomez H. Phyllodes tumor of the breast, clinicopathological features and prognostics factors in a retrospective cohort with 7-year follow-up. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-10-18.