Intensity modulated radiotherapy for sinonasal malignancies with a focus on optic pathway preservation.

Abstract

PURPOSE:

To assess if intensity-modulated radiotherapy (IMRT) can possibly lead to improved local control and lower incidence of vision impairment/blindness in comparison to non-IMRT techniques when treating sinonasal malignancies; what is the most optimal dose constraints for the optic pathway; and the impact of different IMRT strategies on optic pathway sparing in this setting.

METHODS AND MATERIALS:

A literature search in the PubMed databases was conducted in July, 2012.

RESULTS:

Clinical studies on IMRT and 2D/3D (2 dimensional/3 dimensional) RT for sinonasal malignancies suggest improved local control and lower incidence of severe vision impairment with IMRT in comparison to non-IMRT techniques. As observed in the non-IMRT studies, blindness due to disease progression may occur despite a lack of severe toxicity possibly due to the difficulty of controlling locally very advanced disease with a dose ≤ 70 Gy. Concurrent chemotherapy's influence on the the risk of severe optic toxicity after radiotherapy is unclear. A maximum dose of ≤ 54 Gy with conventional fractionation to the optic pathway may decrease the risk of blindness. Increased magnitude of intensity modulation through increasing the number of segments, beams, and using a combination of coplanar and non-coplanar arrangements may help increase dose conformality and optic pathway sparing when IMRT is used.

CONCLUSION:

IMRT optimized with appropriate strategies may be the treatment of choice for the most optimal local control and optic pathway sparing when treating sinonasal malignancy.

• Authors: Alexander Chi, Nam P Nguyen, William Tse, Gill Sobremonte, Patrick Concannon, Angela Zhu
• Journal: Journal of hematology & oncology (J Hematol Oncol) Vol. 6 Pg. 4 (Jan 07 2013) ISSN: 1756-8722 [Electronic] England
• PMID: 23294673 (Publication Type: Journal Article, Review)

Topics

• Carcinosarcoma (radiotherapy)
• Dose Fractionation, Radiation
• Humans
• Nose Neoplasms (radiotherapy)
• Radiation Injuries (prevention & control)
• Radiotherapy Planning, Computer-Assisted
• Radiotherapy, Intensity-Modulated
• Teratoma (radiotherapy)
• Vision Disorders (prevention & control)
• Visual Pathways