title: Changes over time in the impact of gene-expression profiles on the administration of adjuvant chemotherapy in estrogen receptor positive early stage breast cancer patients: A nationwide study.
abstract: Ten years ago gene-expression profiles were introduced to aid adjuvant chemotherapy decision making in breast cancer. Since then subsequent national guidelines gradually expanded the indication area for adjuvant chemotherapy. In this nation-wide study the evolution of the proportion of patients with estrogen-receptor positive (ER+) tumors receiving adjuvant chemotherapy in relation to gene-expression profile use in patient groups that became newly eligible for chemotherapy according to national guideline changes over time is assessed. Data on all surgically treated early breast cancer patients diagnosed between 2004-2006 and 2012-2014 were obtained from the Netherlands Cancer Registry. ER+/Her2- patients with tumor-characteristics making them eligible for gene-expression testing in both cohorts and a discordant chemotherapy recommendation over time (2004 guideline not recommending and 2012 guideline recommending chemotherapy) were identified. We identified 3,864 patients eligible for gene-expression profile use during both periods. Gene-expression profiles were deployed in 5% and 35% of the patients in the respective periods. In both periods the majority of patients was assigned to a low genomic risk-profile (67% and 69%, respectively) and high adherence rates to the test result were observed (86% and 91%, respectively). Without deploying a gene-expression profile 8% and 52% (p <0.001) of the respective cohorts received chemotherapy while 21% and 28% of these patients received chemotherapy when a gene-expression profile was used (p 0.191). In conclusion, in ER+/Her2- early stage breast cancer patients gene-expression profile use was associated with a consistent proportion of patients receiving chemotherapy despite an adjusted guideline-based recommendation to administer chemotherapy.
authors.affiliation: Department of Surgery, Diakonessenhuis Utrecht, the Netherlands.|Department of Radiology, University Medical Center Utrecht, the Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Kuijer
authors.affiliation: Department of Surgery, Albert Schweitzer Hospital, Dordrecht, the Netherlands.
authors.forename: C A
authors.initials: CA
authors.lastname: Drukker
authors.affiliation: Department of Epidemiology, Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: S G
authors.initials: SG
authors.lastname: Elias
authors.affiliation: Department of Medical Oncology, Antoni Van Leeuwenhoek Hospital - Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: C H
authors.initials: CH
authors.lastname: Smorenburg
authors.affiliation: Department of Surgery, Antoni Van Leeuwenhoek Hospital - Netherlands Cancer Institute, Amsterdam, the Netherlands.
authors.forename: E J
authors.initials: EJ
authors.lastname: Th Rutgers
authors.affiliation: Department of Research, Netherlands Comprehensive Cancer Organization (IKNL), Utrecht, the Netherlands.
authors.forename: S
authors.initials: S
authors.lastname: Siesling
authors.affiliation: Department of Surgery, Diakonessenhuis Utrecht, the Netherlands.
authors.forename: Th
authors.initials: T
authors.lastname: van Dalen
mesh_terms: D000328:Adult; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor; D001943:Breast Neoplasms / Q000175:diagnosis / Q000188:drug therapy / Q000453:epidemiology* / Q000235:genetics*; D017024:Chemotherapy, Adjuvant; D015331:Cohort Studies; D003131:Combined Modality Therapy; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D009426:Netherlands / Q000453:epidemiology; D011159:Population Surveillance; D017410:Practice Guidelines as Topic; D011960:Receptors, Estrogen / Q000235:genetics*; D012042:Registries; D013997:Time Factors; D059467:Transcriptome; D016896:Treatment Outcome
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen
keywords: 21-recurrence score; 70-gene signature; adjuvant chemotherapy; breast cancer; gene-expression profiling