Surgical Resection Followed by Adjuvant Radiation Therapy
For this 64-year-old woman with a large (3.5-3.8 cm) right frontal brain mass causing significant mass effect and subfalcine herniation, proceed immediately with right frontal craniotomy for tumor resection to establish tissue diagnosis and relieve life-threatening mass effect, followed by adjuvant radiation therapy based on final pathology. 1
Immediate Surgical Intervention is Mandatory
Surgery is the standard of care for symptomatic, large (≥30 mm), accessible brain masses causing mass effect and herniation, regardless of whether this represents metastatic disease or primary CNS malignancy 1, 2
The 3.8 cm size with 8mm midline shift and subfalcine herniation creates immediate risk of neurological deterioration and requires urgent decompression 2, 3
Surgical resection serves dual critical purposes: (1) relief of mass effect to prevent further herniation and neurological decline, and (2) definitive tissue diagnosis to guide subsequent therapy 1
For lesions >3 cm with significant mass effect, surgery is strongly preferred over stereotactic radiosurgery (SRS), which cannot provide immediate decompression 2
Rationale for Surgery Over Biopsy Alone
Complete macroscopic resection should be the surgical objective rather than stereotactic biopsy, given the accessible frontal location and need for mass effect relief 1
The necrotic infracarinal lymph node raises concern for metastatic disease, but the solitary brain lesion with marked edema is also consistent with glioblastoma 4, 5
Establishing histologic diagnosis via resection is essential when the primary cancer is unknown or genetic context unclear, as management differs dramatically between metastatic disease and primary brain tumors 1, 4
Without tissue diagnosis, you cannot determine whether this requires treatment as metastatic disease (potentially with systemic therapy targeting the primary) versus primary CNS malignancy (requiring different radiation fields and chemotherapy regimens) 4, 5, 6
Adjuvant Therapy Based on Pathology
If Pathology Shows Metastatic Disease:
Postoperative stereotactic radiosurgery (SRS) to the resection cavity is preferred over whole-brain radiation therapy (WBRT) for single metastasis in patients with controlled or controllable systemic disease 1, 2
SRS plus WBRT represents a category 1 recommendation for single brain metastasis, though SRS alone is a reasonable category 2A option to preserve neurocognitive function 1
WBRT (30-45 Gy in 1.8-3.0 Gy fractions) should be reserved for patients with multiple metastases or uncontrolled systemic disease 1
Systemic therapy targeting the primary malignancy should be initiated once identified, as the necrotic mediastinal node suggests active systemic disease 1
If Pathology Shows Primary CNS Malignancy (e.g., Glioblastoma):
Postoperative focal radiation therapy to the tumor bed is standard, typically 60 Gy in 2 Gy fractions with concurrent and adjuvant temozolomide 1, 6
For high-grade gliomas (WHO grade 3-4), adjuvant chemotherapy with temozolomide has demonstrated survival benefit 6
Craniospinal radiation is NOT indicated for primary brain tumors unless there is documented leptomeningeal spread 1
Additional Diagnostic Workup
EBUS-guided transbronchial needle aspiration (EBUS-TBNA) of the necrotic infracarinal lymph node should be considered if brain pathology is inconclusive or to identify the primary malignancy site 1
However, do not delay craniotomy for additional systemic staging, as the mass effect requires urgent surgical decompression 1
PET-CT may help identify occult primary malignancy if multiple brain lesions are present and no primary has been found, but this is less relevant with a solitary lesion 1
Perioperative Management (Continue Current Regimen)
Continue dexamethasone 4 mg IV every 6 hours for vasogenic edema management, though doses up to 16 mg/day in divided doses are reasonable for significant mass effect 1
Taper steroids as quickly as clinically tolerated post-resection (ideally within 3 weeks) to minimize toxicity including personality changes, immunosuppression, and impaired wound healing 1
Continue levetiracetam 500 mg IV twice daily for seizure prophylaxis perioperatively 1
Maintain VTE prophylaxis and ICU-level monitoring given the significant mass effect and herniation risk 1
Critical Pitfalls to Avoid
Do not pursue WBRT as initial therapy without tissue diagnosis, as this would be inappropriate if the lesion represents primary glioblastoma requiring focal radiation with different dosing 1, 4
Do not delay surgery for extensive systemic staging when mass effect and herniation are present, as neurological deterioration can occur rapidly 1, 7
Do not assume metastatic disease based solely on the mediastinal lymph node, as primary brain tumors (particularly glioblastoma) can present with solitary lesions and incidental benign lymphadenopathy 4, 5
Avoid stereotactic biopsy alone when complete resection is feasible, as this provides inferior mass effect relief and may require repeat surgery if initial sampling is non-diagnostic 1
Prognosis Considerations
For single brain metastasis with controlled systemic disease (RPA class I), median survival is 7-10 months with aggressive multimodal therapy including surgery and radiation 1
For glioblastoma, median survival is less than 12 months even with maximal therapy including surgery, radiation, and temozolomide 4, 6
The presence of the necrotic mediastinal node suggests systemic disease burden that may limit overall prognosis, though isolated brain progression with controlled systemic disease carries better outcomes 1