Inappropriate or delayed initial management of musculoskeletal neoplasms can lead to severe consequences, emphasizing the need to define core competencies for frontline practitioners. Such competencies can guide medical education and residency training objectives. This study aimed to identify core clinical competencies required by general practitioners and general orthopedic surgeons without oncologic training for the initial management of musculoskeletal tumors, with a focus on implications for medical education. A two-round modified Delphi method engaged 225 members of the Latin-American Tumor Society (SLATME) through an online questionnaire on competencies for evaluating and treating musculoskeletal tumors. Of these, 136 participated in the first round, and 111 in the second. Consensus was defined as 80% agreement on competencies being essential for the described scenarios. Consensus for all frontline practitioners included the ability to determine the need for standard or urgent referral to oncology specialists. For general orthopedic surgeons, additional competencies included performing focused anamnesis and physical exams emphasizing oncologic history, requesting and interpreting appropriate imaging and laboratory tests, and recognizing aggressive features on imaging with or without radiology input. No surgical procedure achieved strong consensus; however, there was moderate agreement that internal fixation of a pathological fracture in metastatic patients is a core competency. This study established consensus on essential evaluation competencies for frontline practitioners assessing musculoskeletal tumors. While procedural competencies for general orthopedic surgeons without oncologic training lacked consensus, the findings provide a foundation for educational priorities and guide initial patient management expectations in such settings. The results can be utilized to shape medical school curricula, residency training, and continuing medical education programs.