ESTRO meets Asia 2024 - Abstract Book

S194

Interdisciplinary – Head & neck

ESTRO meets Asia 2024

fractions should be adopted (U) to the high-risk PTV, intermediate-risk PTV and to low-risk PTV if it is planned (U). The target volumes should be delineated considering the response to the ICT (Table).

Target Volume Definition

Strength

GTVp

Residual disease

S

Pre-ICT bone invasion

S

GTVn

Residual disease

U

HR-CTVp

GTVp + 3-5mm margin

M

Whole nasopharynx

M

HR-CTVn

GTVn + 5mm margin

M

Pre-ICT extra nodal soft tissue extension

S

IR-CTVp

HR-CTVp + 5mm margin S All pre-ICT extension, uninvolved inferior half of sphenoid, uninvolved posterior nasal cavity, anterior half of clivus if not involved and entire clivus if it is involved S

IR-CTVn

Pre-ICT involved neck node levels and uninvolved neck level IIa

S

LR-CTV

(if Levels II-III-Va if not already included in IR-CTVn

W

delineated)

Level Ib if level IIA is involved with extracapsular invasion S level Ib if level IIA is involved with a node >2 cm or if there is massive anterior nasal cavity involvement . W

Conclusion:

To our knowledge, this is the first consensus that define optimal post-IC RT timing and imaging modalities for NPC patients. It also defines dose levels, fractionation and precise target volumes definition after ICT. After the first round, strong consensus to consider the response to ICT when defining RT target volumes was achieved. At least Another round of voting is planned to further investigate questions where consensus was not reached. Then, final results will be published to better guide NPC RT after ICT.

Keywords: nasopharyngeal carcinoma, induction, consensus

References:

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