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Vidula N, Niemierko A, Malvarosa G, Yuen M, Lennerz J, Iafrate AJ, Wander SA, Spring L, Juric D, Isakoff S, Younger J, Moy B, Ellisen LW, Bardia A. Tumor Tissue- versus Plasma-based Genotyping for Selection of Matched Therapy and Impact on Clinical Outcomes in Patients with Metastatic Breast Cancer. Clin Cancer Res 2021; 27:3404-3413. [PMID: 33504549 DOI: 10.1158/1078-0432.ccr-20-3444] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/08/2020] [Accepted: 01/22/2021] [Indexed: 11/16/2022]
Abstract
PURPOSE Actionable mutations can guide genotype-directed matched therapy. We evaluated the utility of tissue-based and plasma-based genotyping for the identification of actionable mutations and selection of matched therapy in patients with metastatic breast cancer (MBC). EXPERIMENTAL DESIGN Patients with MBC who underwent tissue genotyping (institutional platform, 91-gene assay) or plasma-based cell-free DNA (cfDNA, Guardant360, 73-gene assay) between January 2016 and December 2017 were included. A chart review of records to identify subtype, demographics, treatment, outcomes, and tissue genotyping or cfDNA results was performed. The incidence of actionable mutations and the selection of matched therapy in tissue genotyping or cfDNA cohorts was determined. The impact of matched therapy status on overall survival (OS) in tissue genotyping or cfDNA subgroups was determined with Cox regression analysis. RESULTS Of 252 patients who underwent cfDNA testing, 232 (92%) had detectable mutations, 196 (78%) had actionable mutations, and 86 (34%) received matched therapy. Of 118 patients who underwent tissue genotyping, 90 (76%) had detectable mutations, 59 (50%) had actionable mutations, and 13 (11%) received matched therapy. For cfDNA patients with actionable mutations, matched versus nonmatched therapy was associated with better OS [HR 0.41, 95% confidence interval (CI): 0.23-0.73, P = 0.002], and this remained significant in a multivariable analysis correcting for age, subtype, visceral metastases, and brain metastases (HR = 0.46, 95% CI: 0.26-0.83, P = 0.010). CONCLUSIONS Plasma-based genotyping identified high rates of actionable mutations, which was associated with significant application of matched therapy and better OS in patients with MBC.See related commentary by Rugo and Huppert, p. 3275.
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Affiliation(s)
- Neelima Vidula
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts.
| | - Andrzej Niemierko
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Giuliana Malvarosa
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Megan Yuen
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Jochen Lennerz
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - A John Iafrate
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Seth A Wander
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Laura Spring
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Dejan Juric
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Steven Isakoff
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Jerry Younger
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Beverly Moy
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Leif W Ellisen
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
| | - Aditya Bardia
- Massachusetts General Hospital Cancer Center, Harvard Medical School, Boston, Massachusetts
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