LAUSR

Diffuse intrinsic pontine glioma (DIPG) is an aggressive and fatal pediatric brain tumor. Due to its difficult anatomic location and infiltrative nature, DIPGs are not surgically resectable and more than 90% of children die within two years of diagnosis. Historically, standard of care has consisted of clinical and radiological diagnosis followed by palliative radiation for symptomatic relief. Although tumor biopsy is not necessary for diagnosis, there is debate as to whether the procedure provides benefits that outweighs its risk. Recent studies have proposed that biopsy-driven molecular characterization of these tumors can inform prognosis and identify potential treatment targets that could lead to clinical breakthroughs. This study was a retrospective chart review of 26 patients treated for a DIPG diagnosis between July 1998 and July 2019 at Cohen Children’s Medical Center. We compared outcomes of biopsied vs. non-biopsied DIPG patients through quantitative data analyzing the number and types of treatment given. We analyzed post-surgical data regarding safety of DIPG biopsies which were performed by optical stereotactic needle biopsy or robot-assisted stereotactic biopsy procedures. There were no permanent biopsy complications in any patient and biopsy did not delay treatment as average hospital stay was 1.5 days. All biopsies collected sufficient material for next generation sequencing analysis and revealed targetable mutations for available clinical trial therapies. 67% of patients were subsequently enrolled in clinical trials, 75% of which required biopsy results for enrollment. MGMT promoter methylation assay results in all tested DIPG biopsy cases indicated resistance to temozolomide, the most common treatment agent given to non-biopsied patients. Biopsy of DIPG tumors is a safe and accurate procedure that does not delay treatment and identifies molecular targets for individualized therapy. The role of biopsy in DIPG patients allows for molecular characterization of DIPG tumors which informs and increases treatment options.