In terms of item relevance and comprehensiveness, ≥80% of patients reported experiencing at least 11 out of the 16 concepts as a part of the HR+/HER2- advanced breast cancer experience (lack of energy, pain, feeling ill, shortness of breath, family role, fatigue, pain, worry, ability to work, ability to enjoy life, and quality of life), while between 42 and 67% of patients endorsed the remaining five concepts (bone pain, nausea, side effects, hair loss, mouth sores). The gene discussed is ERBB2; the disease is breast cancer.