Second Surgery

Initial tumor type.

Length of time between initial treatment and the reappearance of the mass lesion.

Location of the recurrent tumor.

Consideration of therapeutics based on the requirement for fresh tumor tissue or to deliver therapy to the operative bed.

In most cases of diffuse midline gliomas centered in the pons (diffuse intrinsic pontine glioma [DIPG]), biopsy at the time of clinical or radiological progression is neither necessary nor recommended. Biopsy may be considered for confirmation of relapse when treatment-related brain stem damage, which may be clinically indistinguishable from tumor recurrence, is in the differential diagnosis. Other tests, including positron emission tomography, magnetic resonance spectroscopy, and single-photon emission computed tomography, are not reliable in distinguishing necrosis from tumor recurrence in previously irradiated patients with DIPG.