To assess the economic and social burden of BC, we considered both the National Health System (NHS) perspective and the social perspective, by including direct healthcare costs and social security costs.

A retrospective cohort observational study was conducted using the Health Information System (HIS) for Italy as a whole (60 million inhabitants) and for Local Health Unit (LHU) Umbria 2 (380,000 inhabitants), data were available from 2010 to 2019 (2010 to 2018 for LHU Umbria 2).

The Italian HIS records all hospital discharges (HD), both ordinary and day-hospital (DH), from public and accredited hospitals. Each record contains, together with a patient specific anonymous code, patient’s demographic (age, sex, residence) and clinical information [primary and up to five secondary diagnoses and procedures, diagnosis-related group (DRG)].

The study populations were represented by all women residing in Italy aged 18–100 years who were hospitalized with a diagnosis of BC. BC hospitalizations were defined by the presence of one of the following diagnoses: “carcinoma in situ of breast” [International Classification of Diseases, ninth Revision, Clinical Modification (ICD-9-CM 233.0)], “malignant neoplasm of female breast” (ICD9CM 174.X), or “secondary malignant neoplasm of breast” (ICD-9-CM 198.81) in the primary or secondary diagnosis fields. Results were stratified by type of diagnosis present in the hospitalization ICD-9-CM codes; patients with two or three different diagnoses in the same year were attributed to the most severe diagnosis (MBC, BC, carcinoma in situ from the most to the least severe). The number of patients, hospitalizations, and the total costs were estimated by year.

The LHU Umbria 2 HIS routinely collects information on hospitalizations, drug prescriptions, outpatient care, and laboratory tests for each patient registered in the Regional Health Care Assistance Registries (approximately 97% of residents). Each patient was identified in the HIS by an anonymous code that allowed deterministic linkage between the databases.

The same analysis described in the National HIS chapter was performed for LHU Umbria 2. By linking all the databases available for LHU Umbria 2, it was possible to estimate the mean direct costs per patient owing to hospitalizations, drugs, and outpatient visits. Hospitalization costs were determined using Italian National Health Service (INHS) DRG reimbursement tariffs. Drug costs were calculated on the basis of the purchase price by INHS. The costs of outpatient services were defined according to national tariffs. Total national direct costs were estimated by multiplying mean costs per patient obtained for the LHU Umbria 2 by the number of prevalent patients obtained from the National analysis, as described in Fig. 1.

Flowchart of the analysis. The flowchart describes the different stages of the analysis as well as the datasets used

In Italy, the Social Security System (SSS) is characterized by a dual structure that includes, on one hand, welfare and civil incapacity care benefits for workers (previdential system), and on the other, social security benefits for the general population (assistential system).

The assistential system provides financial aid and services to people in need, regardless of their contribution history. It is based on the principle of solidarity and is aimed at helping those in situations of poverty, unemployment, disability, or social exclusion. The benefits are not tied to previous contributions by the individual. Instead, they are funded by general taxation and are granted on the basis of specific social needs or conditions, such as low income or severe disability.

Welfare and civil incapacity benefits include the Disability Benefit for those with partial incapacity; the Incapacity Pension for those permanently incapable and the Inability Constant attendance allowance for personal assistance (IA). This is the only benefit available regardless of the applicant’s income, but it requires the recipient to be unable to get around without the permanent help of a carer and to be unable to carry out the tasks of daily life.

The previdential system is primarily focused on providing financial support to individuals who have contributed to the system during their working life. It is financed through mandatory contributions made by both employees and employers during an individual’s working years and aims to replace income in case of disability and only those who have made contributions to the INPS during their career are eligible for these benefits. Specifically, all work categories registered within the Italian National Institute of Social Security are entitled to apply for one of the two social security benefits provided: the Disability Benefit (DB), for those whose work capacity is reduced to less than a third (disability between 67% and 99%); and the Incapacity Pension (IP) in favor of those permanently incapable to carry out any work activity (100% disability). Considering the EU definition of the benefits analyzed, DB corresponds to the Ordinary Incapacity Benefits of the European Commission, while IP corresponds to the Disability Pension. Law no. 222/84 sets the requirements for access to the social security benefits being analyzed [13].

To estimate the social security costs related to breast cancer, information from the database of the National Social Security Institute was used, containing the number of requests submitted each year from 2014 to 2019 (2016 to 2019 for welfare and civil incapacity benefits) by women aged 18+ years, to determine each benefit and the related judgments (approval or rejection) expressed by medical managers. These include the indication of the prevailing diagnosis and any secondary diagnosis on the basis of the international classification of diseases, ninth revision (ICD-9-CM). Following an overall assessment of the physical and mental health of the applicant, the Medical–Legal Centers of the National Social Security Institute approve the request, providing the benefit on the basis of the presence of one or more disabling diseases. The assessment is based exclusively on medical forensic criteria and does not include any examination of socio-economic or other types of factors.

Since information regarding the applicants’ per capita income is not available, only the recognitions whose value is independent of this income have been considered in this exercise (DB, IP, and IA).

Social security beneficiaries and costs were estimated through a probabilistic model with a Monte Carlo simulation by estimating the number of prevalent beneficiaries from the number of incident accepted applications, with a methodology already described elsewhere [14]. Briefly, the percentage of incident breast cancer recognitions was estimated in relation to the total incident recognitions for various benefits (DB, IP, and IA). This percentage was applied to the number of total prevalent benefits by year to estimate the prevalent benefits related to breast cancer. The assumption was made that all recipients received the social benefit across the whole year, since no information was available on the potential revocation of the benefit. To account for potential bias associated with this assumption, a Monte Carlo simulation was conducted; specifically, for the benefits provided and the yearly values we assigned a gamma distribution, while we used the beta distribution for the percentages.

In both analyses (direct and indirect costs) costs were not adjusted for inflation, nominal values were used.