Purpose <p>Molecular testing has become a cornerstone in pediatric neuro-oncology but relies on time intensive workflows at specialized centers. We hypothesized that time to adjuvant therapy has increased since the incorporation of molecular testing.</p> Methods <p>In this retrospective case series, data were collected from Riley Hospital for Children in Indianapolis from the pre-molecular era (2007–2009) and the molecular era (2023–2025). Patients aged ≤ 21 years who received initial surgery for a primary brain tumor were included. The primary outcome of interest was the time from initial surgery to initiation of adjuvant treatment.</p> Results <p>A total of 140 patients met inclusion criteria, including 83 who received adjuvant therapy as part of the initial postoperative treatment plan. Time to adjuvant treatment was significantly shorter in the pre-molecular cohort (24.5 vs 34.2 days). Multivariate analysis demonstrated that this prolonged time to treatment was associated with the use of targeted therapies that rely on molecular testing for diagnosis, and increased patient referrals to external institutions during the molecular era. The most cited reasons for delay in adjuvant treatment were final pathology report pending, family decision making, and shunt-related factors.</p> Conclusion <p>Time to adjuvant therapy was longer in the molecular era, and this effect was attributable to evolving treatment paradigms, specifically the adoption of targeted therapies related to molecular diagnosis and increased reliance on external treatment centers. These results underscore modifiable, system-level barriers in the delivery of precision oncology which represent key opportunities to improve timeliness of care and, ultimately, patient outcomes.</p>