Abstract
PurposeExtension of adjuvant endocrine therapy (ET) reduces the risk of recurrence in women diagnosed with ER-positive breast cancers, but a significant benefit is unlikely to happen to all individual patients. This study is aimed at evaluating the ability of different clinical late distant recurrence (LDR) risk stratification methods and in particular the clinical treatment score at 5 years (CTS5) to predict the response to extended adjuvant ET.Methods783 patients diagnosed with ER+ BC between 1988 and 2014 at Umberto I Hospital of Turin, of which 180 received an extended adjuvant ET, were retrospectively selected. They were stratified according to pT, pN, disease stage, tumor grade, Ki67 level, progesterone receptor status and CTS5. The primary endpoint was LDR rate. LDR rates according to ET duration were confronted in each subgroup.ResultThe median duration of extended ET was 7 years (6–10). Median follow-up from diagnosis was 9 years (6–26). Retrospective risk stratification according to tumor size, nodal status, disease stage, tumor grade, Ki67 level, and progesterone receptor status did not appear to be able to predict the response to extended ET. In the CTS5 high-risk subgroup instead, the risk of developing an LDR was significantly lower in the patients who underwent extended ET compared to standard ET (HR 0.37, 95% CI 0.15–0.91), while no significant benefit was demonstrated for low and intermediate-risk patients.ConclusionsRisk stratification according to CTS5 appeared to be predictive of the response to extended endocrine therapy in our population of real-life pre and postmenopausal patients.
Highlights
Breast cancer is the most frequent neoplasia in women worldwide, and about 80% of new diagnoses are estrogen receptor-positive (ER+) tumors [1]
A metanalysis published by Pan H. et al including more than 60,000 women has shown that the risk of distant recurrence persists for at least 20 years from the diagnosis of an ER+ breast cancer [14]
Many studies have been conducted on this topic: eight RCTs involving more than 17,000 patients were recently included in a metanalysis by Corona et al, which confirmed the beneficial effect of the extended endocrine therapy on DFS but not on OS [15]
Summary
Breast cancer is the most frequent neoplasia in women worldwide, and about 80% of new diagnoses are estrogen receptor-positive (ER+) tumors [1]. Data on extended therapy is limited and will not be applicable in the near future since the SOFT [4] and TEXT [5] trials have revolutionized the clinical practice On these premises, the selection of the patients at higher recurrence risk deemed to get the most benefit from an extended endocrine therapy has become a prominent concern. Contrariwise, the Clinical Treatment Score at 5 years (CTS5), which integrates four clinicopathological variables, was developed to estimate the LDR risk after five years of adjuvant endocrine therapy for ER+ breast cancer It was created and validated on the ATAC and BIG 1–98 cohorts of postmenopausal patients [7] and its prognostic ability has been externally confirmed on different cohorts of pre and postmenopausal patients [8,9,10,11]. Only the Breast Cancer Index (BCI) was shown to be predictive of the response to extended ET [12, 13]
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