Step therapy ("fail-first") policies require patients to initiate treatment with a payer-preferred regimen, often selected for cost, before coverage is granted for the oncologist-recommended therapy. In medical oncology, where biologic heterogeneity, biomarker-directed therapy, and time-sensitive sequencing determine outcomes, step edits can function as an avoidable barrier to evidence-based care. We performed a narrative review of peer-reviewed literature (2010-2025) and relevant U.S. regulatory and policy documents to summarize the clinical, economic, and equity implications of step therapy as applied to systemic anticancer treatments. Evidence from cancer-specific and cross-cutting utilization management research suggests that coverage restrictions can delay initiation or continuation of therapy and increase treatment discontinuation. We synthesize mechanisms of harm (time-to-treatment delays, forced non-guideline-concordant sequencing, and toxicity exposure), describe contemporary case examples across therapeutic areas, and propose actionable policy remedies. Oncology-specific safeguards, including transparent clinical criteria, rapid exceptions and appeals, continuity-of-care protections, and provider performance-based exemptions ("gold-carding"), are essential to balance payer oversight with the imperatives of precision oncology.

Brainstem gliomas (BSG) are rare in adults (less than 2% of all gliomas) and generally have a better prognosis than pediatric BSG, although outcomes remain heterogeneous. Many other central nervous system (CNS) tumors, as well as nontumoral lesions, have been described as differential diagnoses and should be kept in mind. Each case should be examined by neurosurgeons from specialized centers to determine the most appropriate surgical approach among stereotactic biopsy, open biopsy, and tumor resection. Surgery may sometimes be performed in expert centers. The main objectives of tumor tissue sampling are to perform histomolecular analyses to confirm the diagnosis, determine the tumor subtype, and identify potential prognostic and theranostic biomarkers. Tissue preservation is essential to ensure that sufficient tumor material is available for further molecular analyses for diagnostic or therapeutic purposes. Results of ctDNA detection in CSF should only be considered if they are positive. The management of BSGs in adults remains non-standardized, largely because most glioma trials exclude tumors located in this specific site. To date, no prospective trials have established clear treatment guidelines, and most of the available data come from retrospective studies or extrapolation of data from other locations. Radiotherapy (RT) is one of the main treatment options for BSGs in adults. The role of chemotherapy remains unclear due to limited data in literature and is currently being studied. Several molecular targets with therapeutic potential, including recurrent genetic mutations and fusion transcripts, have been identified in adult BSGs.