2.2 Patient population
The medical record number of patients were initially identified using the following billing codes: ICD-9 172, ICD-10 C43, and CPT 11600-11606, 11620-11624, or 11640-11646 (Table 1). Our institution’s Integrated Data Repository identified 5291 patients meeting these criteria and provided medical record numbers. Each patient’s chart was reviewed by study members to determine if the patient had at least one confirmed diagnosis of melanoma, regardless of stage, along with both a biopsy pathology report and a surgical pathology report. Patients whose medical records were incomplete or did not have both pathologic reports were excluded. Of the initial 5291 patients, 236 patients had both biopsy and surgical pathology reports available. After excluding patients with a diagnosis prior to 2010, 227 patients remained. This group was further stratified by stage, including only Stages I (IA and IB) and 2 (II2A, IIB, and IIC) according to American Joint Committee on Cancer’s 8th edition on clinical prognostic grouping for melanoma, resulting in 69 patients [18, 19]. Additionally, 1 patient did not have recurrence information or death status available, so this patient was excluded yielding a final study population of 68. All patients in this cohort were managed with wide local excision of their tumor. Patients were only treated with systemic therapy if they progressed and systemic therapy became indicated.