This study aimed to investigate psychiatric symptomatology in a sample of patients affected by breast cancer undergoing surgery, evaluating the potential mediators on perceived stress levels, depression and hopelessness. The study was conducted on eighty-five patients with breast cancer, admitted consecutively to the Breast Unit of the IRCCS Ospedale Policlinico San Martino, between May 2018 and December 2019. Sociodemographic (age of diagnosis, gender, marital and occupational status, educational level, having children) and clinical (type and side of surgery, previous breast surgery, neoadjuvant chemotherapy and axillary dissection) characteristics were investigated through a semi-structured interview. The following rating scales were administered: Beck Depression Inventory, Beck Hopelessness Scale, and Perceived Stress Scale. Our findings indicate that the presence of children and of a partner was associated with a lower total score on the clinical dimensions evaluated. Furthermore, we found demolitive surgery to be a mediator between perceived stress and hopelessness, while history of previous breast surgery was found to be a mediator between demolitive surgery and perceived stress. In conclusion, patients affected by breast cancer undergoing more complex and demolitive surgery or with history of previous breast surgery should be mostly monitored from a psychological and psychiatric point of view from the beginning of treatments to evaluate the first manifestations of psychiatric symptomatology.