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ESTRO 2020

Session Item

Saturday
November 28
08:45 - 10:00
Interdisciplinary Stream 1
Management of complex skin targets-what is the optimal radiation technique?
00007
Symposium
Interdisciplinary
09:33 - 09:57
Which brachytherapy technique is optimal to manage complex skin targets?
Jose-Luis Guinot, Spain
SP-0013

Abstract

Which brachytherapy technique is optimal to manage complex skin targets?
Authors: VICTOR GONZALEZ-PEREZ.(FUNDACIÓN INSTITUTO VALENCIANO DE ONCOLOGIA, DEPARTMENT OF RADIATION PHYSICS, VALENCIA, Spain), JOSE-LUIS GUINOT.(FUNDACIÓN INSTITUTO VALENCIANO DE ONCOLOGIA, DEPARTMENT OF RADIATION ONCOLOGY, VALENCIA, Spain)
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Abstract Text
Abstract text

Complex skin targets are related to extensive lesions as skull carcinomas with large targets, proximity of organs at risk as eye, anatomic uneven surfaces or cavities, and exophytic lesions. In all these situations, to achieve a good dosimetry is a challenge. New planning systems and high accuracy CLINACs allow for better isodose distributions, but air cavities and irregular shapes are difficult to be well covered. Dose on the skin is also a handicap, and bolus material not always adapts to the skin surface, Brachytherapy (BT) is being used for skin malignancies with excellent results. Most of the indications are related to small, not deep tumors or postoperative radiation to treat a few mm under the skin. These cases are well managed with contact brachytherapy, flaps, molds, or shielded devices. Complex skin targets need a different approach. Extensive superficial skull targets have dosimetric advantages when treated with personalized flaps or molds for contact brachytherapy. Dose is more homogeneous and brain receives lower doses. The proximity of organs at risk like eyes give advantage to interstitial BT due to the rapid fall-off of dose outside the target. Cavities like ear, orbit, nostrils, if included in the target offer the chance of making personalized molds to adapt the isodose to these irregular surfaces. And exophytic tumors need to be radiated with a maximum dose to the skin, what is possible through interstitial needles or plastic tubes fixed with templates, adding extra needles outside of the body with excellent dosimetry and outcome, like lip carcinomas. Brachytherapy is a good alternative to external radiation procedures, and in some situations can become the best option to get better dose distributions and protect organs at risk. Moreover, total treatment time can be reduced to 5-10 days compared with external beam radiation schemes lasting several weeks, what is desirable in elder patients.