In a patient with a malignant lesion over the zygomatic bone, how do we determine surgical candidacy based on tumor biology, anatomic extent, performance status, comorbidities, and prior treatments?

Determining Surgical Candidacy for Malignant Zygomatic Bone Lesions

Surgical candidacy for a cancerous mass overlying the zygomatic bone requires systematic evaluation of tumor resectability with acceptable morbidity, expected survival, performance status, and the ability to achieve negative margins—the single most important prognostic factor for local control and survival. 1, 2

Multidisciplinary Team Evaluation (Mandatory First Step)

• All patients with suspected primary bone malignancies must be evaluated by a multidisciplinary team before any surgical intervention or biopsy 1
• The team must include: musculoskeletal oncologic surgeon, musculoskeletal radiologist, bone pathologist, medical oncologist, and radiation oncologist 1
• This prevents inappropriate biopsies that contaminate tissue planes and compromise subsequent definitive surgery 1

Tumor Biology Assessment

Histologic Confirmation Requirements

• Biopsy must be performed AFTER complete imaging studies and ONLY at the center where definitive management will occur 1
• Core needle biopsy under imaging guidance is preferred over open biopsy when feasible 1
• The biopsy tract becomes contaminated and must be excised en bloc with the definitive resection 1
• Poorly planned biopsies compromise oncologic adequacy in one-third of cases 3

Tumor-Specific Considerations

• For chondrosarcomas (common in facial bones): these are radiation-resistant, making en bloc R0 resection with negative margins the only curative option 2
• Osteosarcomas and Ewing's sarcomas require neoadjuvant chemotherapy before surgical resection 1, 4
• Metastatic lesions: determine primary tumor histology, as highly vascularized metastases (renal, melanoma, thyroid) require preoperative embolization ideally the day before surgery 1

Anatomic Extent Evaluation

Imaging Protocol for Zygomatic Lesions

• Start with biplane conventional radiographs to assess bone destruction pattern, margins, periosteal reaction, and matrix characteristics 1, 5
• CT without contrast is essential for zygomatic lesions due to complex anatomy—it optimally visualizes cortical destruction, matrix mineralization, and extent of bone involvement 1
• MRI with contrast of the entire affected region including adjacent joints is mandatory for surgical planning to delineate tumor from adjacent structures 1
• Chest CT is required to exclude pulmonary metastases 1

Resectability Criteria

• The tumor is resectable if wide excision with histologically negative margins can be achieved 1
• Resectable with unacceptable morbidity = functionally unresectable 1
• Assess involvement of: orbital contents, skull base, intracranial extension, major neurovascular structures (facial nerve, internal carotid artery) 2
• For skull base involvement with intracranial extension: gross total resection is achievable in 81-84% of cases with acceptable morbidity 2

Performance Status and Expected Survival

Prognostic Scoring

• Use validated prognostic scores to estimate expected survival—this directly determines surgical approach 1
• Performance status is a critical ESTRO criterion for selecting candidates for ablative treatment 1

Survival-Based Decision Algorithm

• Expected survival >6-12 months: pursue definitive resection with complex reconstruction if negative margins achievable 1
• Expected survival <6 months: consider palliative radiation (50-60 Gy) or minimally invasive stabilization procedures 1
• For metastatic disease: number of metastases, primary tumor histology, and systemic treatment response guide candidacy 1

Comorbidity Assessment

Surgical Risk Factors

• Oncologic surgery carries high morbidity: hemorrhage, infection, thromboembolic events 1
• Age >50 years with vascular disease (hypertension, diabetes, hyperlipidemia) increases risk of postoperative complications 1
• An interval must be observed between surgery and systemic treatments (chemotherapy, anti-VEGF therapy) to limit postoperative complications 1

Contraindications to Surgery

• Active uncontrolled infection at surgical site 1
• Medical comorbidities precluding general anesthesia for the required operative duration (typically 8-12 hours for complex skull base resections with reconstruction) 2
• Inability to tolerate postoperative intensive monitoring for flap viability and neurological status 2

Prior Treatment History

Impact on Surgical Candidacy

• Previous radiation to the area increases surgical complications including wound healing disorders and risk of radionecrosis 1
• Prior inadequate surgery with positive margins: recurrence rate approaches 100% without adequate re-resection 3
• For recurrent disease after prior surgery: consider more aggressive resection (marginal or en-bloc) as recurrence indicates inadequate initial treatment 6

Chemotherapy Response

• For osteosarcoma/Ewing's sarcoma: poor histological response to neoadjuvant chemotherapy (<90% necrosis) is an adverse prognostic factor but not an absolute contraindication to surgery 1
• Tumor progression on systemic therapy may indicate need for local control with surgery or radiation 1

Reconstruction Feasibility

Critical for Surgical Candidacy

• Free flap reconstruction is required for large defects following skull base/zygomatic resection 2
• Healthy surrounding bone is necessary for proper fixation and hardware durability 1
• Facial nerve transposition and obliteration of pneumatic spaces are often required for infratemporal fossa involvement 2

Key Surgical Candidacy Algorithm

1. Confirm diagnosis via properly planned biopsy at treating center 1
2. Complete staging with CT (for bone detail) and MRI (for soft tissue extent) 1
3. Assess resectability: Can negative margins be achieved? 1, 2
4. Evaluate morbidity: Is functional outcome acceptable? 1
5. Calculate expected survival: >6-12 months favors surgery 1
6. Verify performance status adequate for major surgery 1
7. Confirm reconstruction feasible with available techniques 2

Critical Pitfalls to Avoid

• Never perform biopsy before complete imaging—this contaminates tissue planes 1
• Never attempt surgery at a non-specialized center—inadequate procedures have 100% recurrence rates 3
• Never assume bilateral symptoms are systemic—consider mechanical obstruction from tumor 7
• Never proceed without multidisciplinary review—errors in diagnosis occur in one-third of cases without proper coordination 3, 5