Patterns of local failure for sinonasal malignancies

Area of Science:

• Radiation Oncology
• Head and Neck Cancer
• Medical Imaging

Background:

• Sinonasal malignancies are rare but aggressive tumors.
• Radiation therapy (RT) is a key treatment modality for these cancers.
• Understanding patterns of local failure is crucial for improving treatment outcomes.

Purpose of the Study:

• To investigate the spatial patterns of local failure in sinonasal malignancies after radiation therapy.
• To categorize failures as in-field, marginal, or out-of-field.
• To correlate failure patterns with treatment parameters and tumor location.

Main Methods:

• Retrospective review of 79 patients with sinonasal malignancies treated between 2000-2011.
• Analysis of local failures (persistent disease or local recurrence) in 26 patients.
• Image registration of failures to treatment planning CT scans.
• Categorization of failures based on isodose line coverage.

Main Results:

• Fifteen patients experienced local recurrence (LR).
• Of these, 6 were out-of-field and 2 were marginal, totaling 53% of LRs.
• Marginal and out-of-field recurrences were often located superior to the eyes.
• Suboptimal RT dose coverage was noted for many LRs.

Conclusions:

• A significant proportion of local failures in sinonasal malignancies occur outside the intended radiation field.
• The location of these failures, often near critical structures like optic pathways, suggests a trade-off between dose coverage and toxicity.
• Skull base surgical complexity may also contribute to these failure patterns.