Background Corresponding with improved survival among patients with breast cancer, the awareness of the long-term effects of cancer treatments has increased. CANcer TOxicities (CANTO) aims to identify predictors of development and persistence of long-term toxicities in patients treated for stages I–III breast cancer and to characterise their incidence, as well their impact. In this paper, we describe the methodology used in this study and provide a first characterisation of the study population.
Methods CANTO (NCT01993498) is a French prospective, longitudinal cohort study enrolling patients with invasive cT0-cT3cN0-3M0 breast cancer of 26 French cancer centres. Patients are assessed at diagnosis, 3–6 (M0), 12 (M12), 36 (M36) and 60 (M60) months after completion of primary surgery, chemotherapy or radiotherapy whichever comes last. CANTO collects clinical, treatment, toxicity data, an extensive list of validated patient-reported outcomes (focusing on quality of life, psychological and behavioural questionnaires) and ad hoc socioeconomic questionnaires. Blood collection is performed at diagnosis, M0, M12, M36 and M60. Biologic sub-studies are ongoing (eg, microbiotic and cognitive sub-study).
Results Enrolment started in 2012; by October 2018, 12 012 patients had been enrolled. Data collected have a low missing completion rate (<5% for key clinical variables, <20% for patient-reported outcomes). Blood, serum and plasma samples are stored in over 96% of patients. Among the first 5801 patients enrolled in CANTO, 76.7% of patients had hormone receptor positive and human epidermal growth factor 2 negative tumours; 73.1% of patients had breast conserving surgery; 90.4% received adjuvant radiotherapy, 53.4% (neo) adjuvant chemotherapy, 11.3% adjuvant trastuzumab and 80.3% adjuvant hormonotherapy.
Conclusions CANTO represents a unique opportunity to explore important medical, biological and psychosocial outcomes on breast cancer survivor population.
- cohort study
- breast cancer
- quality of life
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FA and PA contributed equally.
Contributors Al authors contributed to the conception and design, acquisition of data, analysis and interpretation of data, drafting the manuscript or revising it critically for important intellectual content, gave final approval of the version to be published and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Funding The study was supported by the Agence Nationale pour la Recherche (ANR-10-COHO-0004).
Competing interests IVL: Honoraria: AstraZeneca, Novartis, Kephren, outside the submitted work. PC: Honoraria: AstraZeneca, Nanostring Technologies, Novartis, Pfizer, Roche; Consulting or advisory role: Novartis, Pfizer; Research funding: AstraZeneca (Institutional), Novartis, Pfizer, Pierre Fabre (Institutional); Travel and accommodation expenses: Novartis, Pfizer, Roche, outside the submitted work. OT: Honoraria: Roche, MSD, Novartis, Lilly, Astra Zeneca; Grants: Roche MSD, BMS, outside the submitted work. Other authors: no relationships to disclose.
Patient consent for publication Not required.
Ethics approval The study was approved by French regulatory authorities (14 September 2011) and French ethics committee (14 October 2011).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement The data sets used and/or analysed during the current study are available from the corresponding author on reasonable request.
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