Abstract 319P
Background
The incidence of Oligometastatic (OM) breast cancer (BC) is ∼ 20-50%. OM is an intermediate state between localized and widely metastatic (met.) disease. Treatment of OM is controversial, the status of no evidence of disease (NED) can be achieved through multidisciplinary management (systemic and local therapies: surgery +/- radiotherapy). The aim was to evaluate the prognostic role of NED status in OM BC patients (pts).
Methods
A retrospective study was performed in a single institution including 54 non-consecutive OM pts who achieved NED status. Pts were recruited from Jan-88 to Dec-17. Enrolled pts should have the following inclusion criteria: ECOG: 0-1, no relevant comorbidities and no contraindication to surgery. OM disease was defined as < 5 mets. in a single organ. Kaplan–Meier was used to estimate progression-free and overall survival (PFS and OS). Multivariable Cox regression analysis was performed with backward-forward stepwise model selection with AIC.
Results
We identified 54 OM pts (Table), 15% were de novo metastatic and 85% relapsed from the early stage (median DFS: 46 mos). 75.9% were luminal, 16.7% HER2+, and 7.4% triple negative. An induction with presurgical treatment was performed in 17% of pts. Radical metastasectomy was performed in 87% and 13% of pts received radical radiotherapy. 68.1% had a single met. lesion and the most frequent met. site was bone (33%). The median PFS and OS were 84 and 130.5 mos. respectivelly (resp.). At 5-year PFS and OS were 57.4% and 78.9% resp. The median OS in the metastatic setting was 54 mos. Worse DFS (< 45 mos.) (log rank p= 0.017) and the presence of visceral mets. (log rank p= 0.006) were related to worse prognosis. Number of mets. and BC subtypes were not prognostic factors. Cox regression highlighted the role of visceral mets. over others in determining prognosis (p= 0.016). Table: 319P
| Characteristic | Patients, n | (%) |
| Age (years, median) (range) | 43 (31 - 71) | |
| Metastasis localization | ||
| Non-visceral | ||
| Bone | 18 | 33,3 |
| Skin | 5 | 9,2 |
| Nodes | 10 | 18,5 |
| Visceral | ||
| Liver | 8 | 14,8 |
| Lung | 5 | 9,2 |
| Ovarian | 5 | 9,2 |
| Brain | 3 | 5,5 |
| Subtypes BC | ||
| Luminal | 41 | 75,9 |
| HER2+ | 9 | 16,6 |
| Triple Negative | 4 | 7,4 |
| Stage | ||
| I | 19 | 35,1 |
| II | 8 | 14,8 |
| II | 20 | 37,0 |
| IV | 7 | 12,9 |
Conclusions
OM BC represents a challenge for therapeutical management. Non-visceral mets. and long DFS confer a better prognosis in this setting.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
INCLIVA Biomedical Research Institute.
Funding
Has not received any funding.
Disclosure
A. Lluch: Non-remunerated activity/ies, Clinical Research: Amgen; Non-remunerated activity/ies, Clinical Research: AstraZeneca; Non-remunerated activity/ies, Clinical Research: Boehringer Ingelheim; Non-remunerated activity/ies, Clinical Research: GSK; Advisory/Consultancy, Clinical Research: Novartis; Advisory/Consultancy, Clinical Research: Pfizer; Advisory/Consultancy, Clinical Research: Roche/Genentech; Non-remunerated activity/ies, Clinical Research: Eisai; Advisory/Consultancy, Clinical Research: Celgene; Non-remunerated activity/ies, Clinical Research: Pierre Fabre; Non-remunerated activity/ies, Academic Research Projects: GEICAM; Non-remunerated activity/ies, Academic Research Projects: SOLTI; Non-remunerated activity/ies, Academic Research Projects: AECC. All other authors have declared no conflicts of interest.