Patients with metastatic breast cancer may respond well to treatment and metastases can remain stable for several years. Despite personalised medicine being increasingly used for diagnosis and treatment, follow-up still include radiological response evaluation every 3-4 months, which renders a significant number of 'unnecessary' exams for patients with long-term stable disease. Increasing evidence indicates that tumour markers such as circulating tumour DNA (ctDNA), thymidine kinase 1 (TK1) and cancer antigen 15-3 (CA15-3) may be useful for disease monitoring in the metastatic setting. However, algorithms that accurately define the time-points at which imaging can be foregone or reinstituted when progression is forecast, have not been developed. This study will measure ctDNA, TK1 and CA15-3 at all imaging time-points. The primary aim is to develop an algorithm based on these biomarkers, alone or in combination, that with sufficient specificity and sensitivity can advise whether a scan can be safely omitted at a specific time-point, for patients with MBC receiving first line therapy with AI plus cyclin dependent kinase 4/6 inhibitor (CDK4/6i). Additional samples will be stored such that novel biomarkers can also be tested in future. The cost-effectiveness of using the devised biomarker protocol will be evaluated.
One hundred patients with estrogen receptor positive (ER+)/ Human epidermal growth factor receptor negative (HER2-) metastatic or locally advanced breast cancer, eligible for 1st line endocrine therapy with AI + CDK4/6i will be included. Patients will receive standard therapy (AI + CDK4/6i) and follow-up will proceed according to local guidelines, namely cross sectional imaging with CT thorax/abdomen/pelvis +/- MRI as required and analysis of CA 15-3, every 3 cycles for the first year and every 3-4 cycles thereafter. Participation in the study will include serial blood sampling for the bespoke study biomarkers. Decisions on progression will be made according to the routine imaging tests and the biomarkers will be subsequently analysed. The investigators hypothesise that the biomarkers ctDNA, TK1 and CA15-3, alone or in combination, will accurately correlate with disease status in patients receiving AI + CDK4/6i for metastatic breast cancer such that routine imaging can be delayed until predefined levels of biomarker progression. Primary aim: To develop a biomarker-based prediction model to be used in patients with metastatic breast cancer, receiving first line therapy with AI and CDK4/6i, that provides the physician with a recommendation whether or not a radiological examination is required, based on the likelihood that the scan will actually show progressive disease. Secondary aims * To define the lead time between rising biomarker and subsequent progression on imaging * To define the clinical utility of the bespoke biomarkers for disease monitoring * The relative value of analysing TK1 "on CDK4/6i treatment" versus "off CDK4/6i treatment" for disease monitoring * To define the economic impact of implementation of the chosen prediction model
Study Type
OBSERVATIONAL
Enrollment
97
Department of Oncology, Sahlgrenska University Hospital
Gothenburg, Sweden
Department of Oncology, Ryhov Hospital
Jönköping, Sweden
Department of Oncology, Kalmar Hospital
Kalmar, Sweden
Department of Oncology, Linköping University Hospital
Linköping, Sweden
Department of Oncology, Södersjukhuset
Stockholm, Sweden
The Christie NHS Foundation Trust
Manchester, United Kingdom
Wigan Infirmary, Wrightington, Wigan and Leigh NHS Foundation Trust
Wigan, United Kingdom
Change in blood levels of ctDNA, CA15-3 and TK-1 assays from baseline to disease progression
ctDNA, CA15-3 and TK-1 assays will be performed at baseline, 2 weeks and at every imaging timepoint to develop a statistical algorithm to predict disease progression that can be tested prospectively in future studies.
Time frame: 3-5 years
Best time for TK1 analysis during CDK4/6i treatment ("on treatment" vs "off treatment")
The relative value of analysing TK1 "on CDK4/6i treatment" versus "off CDK4/6i treatment" for disease monitoring
Time frame: 3-5 years
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