Diagnosis, biology and epidemiology of oligometastatic breast cancer

Abstract

Does oligometastatic breast cancer (OMBC) deserve a dedicated treatment? Although some authors recommend multidisciplinary management of OMBC with a curative intent, there is no evidence proving this strategy beneficial in the absence of a randomized trial. The existing literature sheds little light on OMBC. Incidence is unknown; data available are either obsolete or biased; there is no consensus on the definition of OMBC and metastatic sites, nor on necessary imaging techniques. However, certain proposals merit consideration. Knowledge of eventual specific OMBC biological characteristics is limited to circulating tumor cell (CTC) counts. Given the data available for other cancers, studies on microRNAs (miRNAs), circulating tumor DNA (ctDNA) and genomic alterations should be developed Finally, safe and effective therapies do exist, but results of randomized trials will not be available for many years. Prospective observational cohort studies need to be implemented.

Clinical and pathological characterization of 158 consecutive and unselected oligometastatic breast cancers in a single institution

“…In this cohort, incidence is signi cantly higher than the 1-10% frequently proposed. The latter value is obsolete, as has been previously shown [14]. Our result is closer to more recent data: 17.3% for synchronous OMBC [16], 23.1% for synchronous and metachronous OMBC [17], 16.9% and 21.9% for metachronous OMBC [24,25] and 31% for HR + metachronous OMBC [20].…”

“…Also available are imagery techniques with high sensitivity and speci city [11][12][13]. However, OMBC incidence remains uncertain: values in the literature are based on outdated studies [14] or come from highly selected series of OMBC [15]. Furthermore, data on OMD speci c biomarkers are limited [9], and a recent review con rms that data on OMBC biology are also scarce [14].…”

“…However, OMBC incidence remains uncertain: values in the literature are based on outdated studies [14] or come from highly selected series of OMBC [15]. Furthermore, data on OMD speci c biomarkers are limited [9], and a recent review con rms that data on OMBC biology are also scarce [14]. It thus remains unclear whether a limited number of metastases at diagnosis re ects speci c biology, early diagnosis of metastases, or both.…”

De Novo Oligometastatic Breast Cancer

“…17,18 Approximately 40% of newly diagnosed metastatic breast cancers, including de novo disease, are oligometastatic. 19,20 Multiple studies showed longer overall survival (OS) for oligometastatic de novo metastatic breast cancers, which may be due to (1) slower growth rate and more limited metastatic ability of these cancers, (2) lead time bias (ie, being diagnosed at an earlier time point during the course of the disease), or (3) more aggressive treatment approaches including local ablative therapy in addition to systemic therapy. 21,22 The individual contributions of these potential causes are difficult to distinguish on the basis of current data.…”