Title: Personalizing the Pediatric Hematology/Oncology Fellowship: Adapting Training for the Next GenerationScott C. Borinstein M.D., Ph.D.1*, Melissa Rose D.O.2, Scott Moerdler M.D.3, Richard Ho M.D.1Department of Pediatrics, Vanderbilt University Medical Center, Nashville, TN USADepartment of Pediatrics, This Ohio State University College of Medicine, Division of Pediatric Hematology-Oncology, Nationwide Children’s, Columbus, OH USADepartment of Pediatrics, Rutgers Robert Wood Johnson Medical School, Rutgers Cancer Institute* Corresponding Author AddressScott C. Borinstein M.D., Ph.D.Professor of PediatricsVanderbilt University Medical Center390 PRB, 2220 Pierce Ave.Nashville, TN 37232Telephone: 615-936-1762Fax: 615-936-1767E-mail: scott.c.borinstein@vumc.orgWord Count:Abstract: 99 wordsMain Text: 2072 wordsShort Running Title: Adapting Fellow education for the next generationKeywords: fellowship, training, workforce, personalizationAbbreviation Key

Background/Objective: Osteosarcoma treatment incorporates chemotherapy and surgery. Resection of the primary tumor usually occurs after induction chemotherapy. Occasionally, scheduling challenges and medical complications result in delay. The goal of this study is to determine if an increased interval between completion of neoadjuvant therapy and surgical resection correlates with decreased tumor necrosis and inferior outcomes in children and young adults with osteosarcoma. Design/Method: We conducted a retrospective chart review of 121 patients age less than 40 years diagnosed with osteosarcoma treated at a single tertiary medical center between 2000-2022. Inclusion criteria included receipt of two cycles of neoadjuvant methotrexate, cisplatin, and doxorubicin. Association of the interval from completion of induction chemotherapy to resection with tumor necrosis (Spearman’s correlation) and outcomes (multivariable Cox hazard regression) were analyzed. Results: There was no significant correlation between interval length and tumor necrosis. However, patients with an interval greater than 16 days had lower 5-year event free survival (p=0.019). Multivariable adjusted analysis of patients with initially localized disease revealed that each day increase in interval length corresponds with a 1.1 times greater hazard of having an event (95% CI: 1.02 to 1.19; p=0.016). Conclusion: Delays in local control were not associated with tumor necrosis. This is consistent with the hypothesis that tumor necrosis is a biologic marker of a tumor’s sensitivity to chemotherapy and may not be affected by minor regimen aberrations. However, surgical delay from completion of induction chemotherapy may confer worse outcomes. Longer intervals generally confer worse outcomes in patients with initially localized disease.

Adolescents and young adults (AYAs) with cancer are a unique patient population in oncology. To better understand the current landscape of AYA cancer, an opt-in, secure online survey was offered to a general population of AYA patients and survivors. A 28-item online survey was designed for cancer patients and survivors diagnosed between the ages of 18 and 39 years. 590 patients registered and 447 (76%) completed the survey. This online survey was feasible and can serve as an effective method to survey the AYA cancer population.