# The Holistic Perspective of the INCISIVE Project--Artificial Intelligence in Screening Mammography
## 3 Data Preparation and Integration
### Data Collection and Integration Experiences  
Breast Cancer  
Once the retrospective data collection study was designed and ethical approval was collected, each data provider could start with a data collection procedure following the provided guidelines related to:  
* a common clinical data schema, i.e., a structural embedding designed to suit all types of information;
* standards of medical terminology to be used, as agreed by a consensus among data providers;  
Figure 4: The ETL process in INCISIVE. * image de-identification (CTP DICOM anonymizer [38]);
* evaluation of the data quality and compliance (Section 3.1);
* image annotation (the ITK-Snap tool [28; 39]). The data organization and naming conventions were imposed to facilitate consistent data structure in the INCISIVE retrospective data repository. The size and heterogeneity of data in healthcare institutions are vast and depend on a hospital's scope and coverage area. In this project, six institutions from four countries acted as data donors for breast-cancer-related data: the Hellenic Cancer Society (HCS), Greece; the German Oncology Center (GOC), Cyprus; Aristotle University of Thessaloniki (AUTH), Greece; the Vojvodina Institute of Oncology (as a scientific base of University of Novi Sad, UNS), Serbia; Federico II University Hospital (providing an imaging service to the Department of Advanced Biomedical Sciences, University of Naples, DISBA), Italy; and Policlinico Tor Vergata of Rome (Faculty of Medicine of the University of Rome Tor Vergata, UNITOV), Italy. The type and scope of these institutions vary from general hospitals such as the AHEPA University Hospital (AUTH), Federico II University Hospital (DISBA), and Policlinico Tor Vergata of Rome (UNITOV) (a non-profit cancer organization linked to multiple hospitals (HCS) and specialized oncology clinics (GOC and UNS). Although national guidelines define breast cancer care pathways, they are aligned around internationally recognized good practice in the diagnosis and treatment of breast cancer [40; 41]. The care pathways in the participating countries correspond to the clinical workflow diagram presented in Figure 5. The patient journey is usually initiated upon a patient self-examination or as a result of a regular annual screening, and all suspected cases are directed to primary healthcare centers. General practitioners (GPs) collect the information, examine the patient, and ensure that patient has been directed to a hospital (one stop breast clinics) or a specialized center for further examination and diagnoses (including mammography (MG), ultrasound (US), and/or magnetic resonance imaging (MRI) if appropriate). Within the same institution, the patient undergoes fine-needle aspiration (FNA) or core biopsy if appropriate. When the suspected case is confirmed, if needed, the patient undergoes additional imaging, such as liver US, abdominal MR, computerized tomography (CT) scans, bone scans, and positron emission tomography (PET). With these clinical and imaging examinations, the first steps of treatment can be defined. Due to the complexity of the disease, diagnostic and therapeutic tools call for the involvement of many specialists, i.e., radiologists, pathologists, oncologists (clinical and radiation), breast surgeons, and nuclear medicine physicians. In the treatment process, the patient is followed by a multidisciplinary team (MDT), including an oncologist, a radiologist, a breast surgeon, and a pathologist, while the patient care, recovery, and support process is assisted by psychological support and rehabilitation services. Post-treatment monitoring includes MR, US, or/and MR imaging at regular intervals, either annual or bi-annual. The clinical workflow results in multiple time points (TPs) on a patient journey which are documented in the common data schema. The number of examinations and reports associated with the described clinical workflow is large (Figure 5), and the way this information is stored in the hospital information system is system-dependent and differs among institutions.