1. Clin Breast Cancer. 2020 Dec;20(6):e695-e700. doi: 10.1016/j.clbc.2020.05.004. 
Epub 2020 May 13.

The Impact of Radiotherapy and Histological Risk Factors on Outcomes in 
Malignant Phyllodes Tumors.

Wong RX(1), Koh YS(2), Wong FY(2), Kusumawidjaja G(2), Ng WL(2), Yeo RMC(2), 
Farid M(3), Sheng Chan JY(3), Yan Z(4), Gudi MA(5), Tan PH(6).

Author information:
(1)Division of Radiation Oncology, National Cancer Centre Singapore, Singapore. 
Electronic address: wong.ru.xin@singhealth.com.sg.
(2)Division of Radiation Oncology, National Cancer Centre Singapore, Singapore.
(3)Division of Medical Oncology, National Cancer Centre Singapore, Singapore.
(4)Department of Surgery, Kandang Kerbau Women & Children Hospital, Singapore.
(5)Department of Pathology and Laboratory Medicine, Kandang Kerbau Women and 
Children Hospital, Singapore.
(6)Division of Pathology, Singapore General Hospital, Singapore.

PURPOSE: Breast phyllodes tumors (PT) are classified into benign, borderline, 
and malignant grades based on histopathologic characteristics. Specific to 
malignant PT (MPT), surgery is the mainstay yet relapse rates are high and 
knowledge gaps in the literature exist regarding adjuvant radiotherapy (RT). We 
aimed to investigate the outcomes of patients with MPT treated in a tertiary 
Asian institution.
METHODS AND MATERIALS: Patients with nonmetastatic MPT treated from February 
1992 to June 2019 were analyzed retrospectively. RT details and relapse fields 
were studied. Outcomes of patients with and without RT were compared and hazard 
ratios were calculated using Cox proportional hazard test. Multivariable 
analysis was performed.
RESULTS: Twenty-two of 89 patients received adjuvant RT and the median dose was 
60 Gy. In the no-RT group, 4 patients received RT on relapse and had no further 
recurrences; a further 2 received RT for fungating relapses with good 
symptomatic relief. RT was only increasingly prescribed after 2004. Median 
follow-up in the RT group was 3.31 years, compared with 6.17 years in the no-RT 
group. In the RT group, 15 patients (68.2%) underwent mastectomy, versus 39 
(58.2%) in the no-RT group. One patient in the RT group developed an infield 
local relapse, compared with 21 of 67 patients in the no-RT group. Multivariate 
model showed that RT decreased risk of locoregional failure (hazard ratio 0.12, 
95% confidence interval [CI] 0.02-0.92, P = .04). Three-year locoregional 
recurrence-free survival was higher in the RT group, 92.3% (95% CI, 78.9-100) 
versus 73.3% (95% CI, 63.1-85.1) in the no-RT group (P = .03). There were no 
differences in 3-year survival.
CONCLUSIONS: We recommend that adjuvant radiotherapy be discussed for malignant 
PT for local control, even after mastectomy.

Copyright © 2020 Elsevier Inc. All rights reserved.

DOI: 10.1016/j.clbc.2020.05.004
PMID: 32636151