Stricter Postoperative Oropharyngeal Cancer Radiation Therapy Normal Tissue Dose Constraints Are Feasible.

Autor:	Su W; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Wright CM; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Lee DY; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Kim M; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Anstadt EJ; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Teo BK; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Carlson DJ; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Lukens JN; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania., Eisbruch A; Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan., Lin A; Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address: alexander.lin2@pennmedicine.upenn.edu.
Jazyk:	angličtina
Zdroj:	Practical radiation oncology [Pract Radiat Oncol] 2022 Jul-Aug; Vol. 12 (4), pp. e282-e285. Date of Electronic Publication: 2022 Mar 15.
DOI:	10.1016/j.prro.2022.03.006
Abstrakt:	Purpose: Although dose de-escalation is one proposed strategy to mitigate long-term toxicity in human papillomavirus associated oropharyngeal cancer, applying more stringent normal tissue constraints may be a complementary approach to further reduce toxicity. Our study demonstrates that in a postoperative setting, improving upon nationally accepted constraints is achievable and leads to reductions in normal tissue complication probabilities (NTCP) without compromising disease control. Methods and Materials: We identified 92 patients at our institution between 2015 and 2019 with p16+ oropharyngeal cancer who were treated with adjuvant volumetric modulated arc therapy. We included patients treated to postoperative doses and standard volumes (including bilateral neck). Doses delivered to organs at risk were compared with recommended dose constraints from a recent cooperative group head and neck cancer trial of radiation therapy to 60 Gy. We applied validated and published NTCP models for dysphagia, dysgeusia, esophagitis, oral mucositis, and xerostomia relevant to oropharyngeal cancer. Results: Achievable and delivered mean doses to most normal head and neck tissues were well below national recommended constraints. This translates to notable absolute NTCP reductions for salivary flow (10% improvement in contralateral parotid, 35% improvement in submandibular gland), grade ≥ 2 esophagitis (23% improvement), grade ≥ 3 mucositis (17% improvement), dysgeusia (10% improvement), and dysphagia (8% improvement). Locoregional control at a median follow-up of 26.3 months was 96.7%, with only 3 patients experiencing locoregional recurrence (1 local, 2 regional). Conclusions: Modern radiation therapy planning techniques allow for improved normal tissue sparing compared with currently established dose constraints without compromising disease control. These improvements may lead to reduced toxicity in a patient population expected to have favorable long-term outcomes. Stricter constraints can be easily achieved and should be used in conjunction with other evolving efforts to mitigate toxicity. (Copyright © 2022 American Society for Radiation Oncology. Published by Elsevier Inc. All rights reserved.)
Databáze:	MEDLINE
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