Breast cancer is the most frequent malignant tumor in women worldwide and in the early non-metastatic stages is curable in about 70–80% of patients. [1] In Italy, the reference country of this study, breast cancer affects about one in nine women, with about 53,000 new diagnoses each year. [2] This pathology has a strong impact on women's health, survival and life. [3] There are 3 major breast cancer subtypes: hormone receptor positive/ERBB2 negative (HR+/ERBB2-), ERBB2 positive (ERBB2+), and triple-negative. [4] Guidelines for the diagnosis, treatment, and follow-up of women with breast cancer are well defined and require a multidisciplinary approach both locally and systemically. [5, 6] For non-metastatic carcinoma, the main goals are eradication of the tumor and regional lymph nodes and prevention of metastasis. On the latter aspect, systemic therapy intervenes, which can be preoperative (neoadjuvant), postoperative (adjuvant) or both. [1] Over the years, surgery has evolved in favor of increasingly conservative approaches. Breast conserving surgery (BCS), now widespread in developed countries, is preferable to a more invasive approach, called mastectomy. However, there are disadvantages related to the persistence of suspicious microcalcifications on imaging or positive pathological margins. [7] Mastectomy is a breast cancer surgery technique in which the surgeon removes the entire breast. There are several different types of mastectomies, based on how the surgery is done and how much tissue is removed. [8] The guidelines state that a cancer unsuitable for BCS (large tumor-to-breast-size ratio, multicentric tumor, etc.), a prophylaxis in high-risk but unaffected patients and patient preference are current indications for mastectomy. [6] In a study conducted by Morrow et al. [9] is reported that in the population analyzed: 13.4% underwent mastectomy on the recommendation of the surgeon usually as a result of a contraindication to BCS or radiation; 8.8% of patients underwent initial mastectomy based on a patient-directed decision; and 8.8% underwent mastectomy after 1 or more failed BCS attempts. In addition, in the United States, there is an increase (from 1.8% in 1998 to 4.5% in 2003) in contralateral prophylactic mastectomy (CPM) done on patients with unilateral breast cancer [10], although the use of the latter has not led to increased survival. [11] The annual incidence of contralateral breast cancer, approximately 0.5–0.75%, does not change over time and it is associated with age and clinical and pathological factors. [10]
From an economic perspective, Capri et al [12] examined the costs of breast cancer during the different stages of the diagnostic-therapeutic sequence by including clinical and patient demographic variables. They showed that the average cost of diagnosis was 414 euros, the average cost of treatment was 8’780 euros, the average total cost of follow-up was approximately 2’351 euros, and the average total direct medical cost was 10’970 euros. Hospitalization accounted for 71% of the total cost (mean cost € 8’242.00) and, among the variables, age was related to lower treatment expenditures while comorbidities limited diagnosis costs.
Given the economic impact and the increasing number of diagnoses, management of the process from a healthcare management perspective is critical. Healthcare data have proven to be important in the diagnosis of different diseases, with the support of tools such as Data Mining [13–17] or Fuzzy Logic [18–19], but also in the optimization of healthcare processes [20–24], exploiting techniques such as Lean Six Sigma. [25–28] A parameter used in several studies as an indicator of quality is the Length of Stay (LOS). [29] LOS is a multidimensional parameter, a function of pathology, patient but also of organizational and institutional factors [30] and several studies have validated linear regression models in classifying and predicting LOS in different healthcare settings. [31–32]
In this study, regression models are used to classify the LOS of patients undergoing mastectomy in the University Hospital "San Giovanni di Dio e Ruggi d'Aragona" of Salerno (Italy). In particular, given the multidisciplinary nature of LOS, clinical and demographic variables of patients involved in the analysis will be included in the model. In the Complex Operative Units of General Surgery, Day Surgery and Breast Unit, included in this work, a previous work was conducted in order to evaluated the impact of COVID-19 on the their hospital activities. [33] Italy was the first European country to be involved in the pandemic and the corrective actions implemented provided that outpatient surgical activities, as well as radiological examinations, were granted only for emergencies suspending screening and elective activities. This will result in a more advanced clinical presentation of breast cancer and more frequent use of mastectomy which demonstrates the importance of this study. [34]