Predicting Outcomes of Breast-Conserving Surgery in Breast Cancer Patients Using the Modified 5-Item Frailty Index

Inclusion Criteria * Data from 14 annual datasets (2008-2021). * Female breast cancer patients identified using diagnostic codes: * ICD-9-CM 174: "Malignant neoplasm of female breast." * ICD-9-CM 233.0: "Carcinoma in situ of breast." * ICD-10-CM C50: "Malignant neoplasm of breast." * ICD-10-CM D05: "Carcinoma in situ of breast." * Focused on patients diagnosed with breast cancer. * Further refinement: * Only patients undergoing breast-conserving surgery (BCS). * Identified by CPT code 19301: "Partial mastectomy without axillary lymphadenectomy." Exclusion Criteria * Missing essential anthropometric data (height and/or weight). * Implausible BMI values (\<7 kg/m² or \>250 kg/m², assumed data entry errors). * Miscoded or vague ICD or CPT entries. * Concurrent invasive procedures other than BCS. * Procedures performed by specialties other than general or plastic surgery. * Male and non-binary patients or those with gender identity disorders (to focus on biologically female cohort). * Non-elective (emergency) surgical cases. * Patients with ASA physical status scores \>4. * Patients receiving anesthesia types other than general anesthesia.