Hormone receptor (HR)-positive/HER2-positive breast cancer represents a distinct subtype expressing estrogen and progesterone receptors with an overexpression of HER2. Approximately 14% of female breast cancer cases are HER2-positive, with the majority being HR-positive. These tumors show a cross-talk between the hormonal and HER2 pathways; the interaction has implications for the treatment options for the disease. In this review, we analyze the biology of HR-positive/HER2-positive breast cancer and summarize the evidence concerning the standard of care options both in neoadjuvant/adjuvant settings and in advanced disease. Additionally, we focus on new trials and drugs for HR-positive/HER2-positive breast cancer and the new entity: HER2-low breast cancer.

Background/objectives: Cancer patients are more vulnerable to SARS-CoV-2 infection and COVID-19 due to their immunocompromised status. This study aims to evaluate the risk of SARS-CoV-2 infection, as well as COVID-19 prevalence and mortality, in cancer patients during the first wave of the COVID-19 pandemic in a virus epicenter of Northern Italy. Methods: This retrospective analysis included 40,148 prevalent cancer patients from the province of Parma, Italy, between February and June 2020. Patients were identified from health system records and classified by cancer subtype, treatment status, and COVID-19 diagnosis. The risk of infection and mortality was analyzed using odds ratios (OR) and hazard ratios (HR). Results: Among cancer patients, those on active cancer treatment had a higher cumulative risk of all-cause death (HR 1.83, p < 0.000268). Cancer subtype significantly impacted COVID-19 outcomes, with breast cancer patients showing lower incidence and mortality compared to those with lung, colorectal, or bladder cancers. Conclusions: Cancer patients, especially those on active treatment, are at increased risk of COVID-19 infection and death. Tailored prevention strategies, including prioritization of vaccination and careful management of cancer treatments, are crucial to mitigate risks during pandemics. These findings provide valuable insights for clinical decision-making in oncological care during public health crises.