Top Line: Does “dysphagia optimized” IMRT improve swallowing outcomes following definitive radiation for head and neck cancer?
The Study: First off, what is dysphagia optimized IMRT (DO-IMRT)? DO-IMRT basically means delineating the pharyngeal constrictor muscles using MRI and constraining them during IMRT optimization. In the DARS trial, 112 patients with oropharyngeal or hypopharyngeal SCC requiring concurrent chemoradiation and bilateral neck irradiation were randomized to standard IMRT or DO-IMRT. In both arms, a 2-volume approach was used. Gross primary and nodal disease plus a 1cm CTV margin and 3-5mm PTV margin received 65 Gy in 30 fractions while an elective CTV covering the primary site and bilateral neck received 54 Gy in the same 30 fractions. In the DO-IMRT arm, the superior/middle and inferior constrictors were delineated on MRI. In addition to the standard OAR constraints, mean dose to the constrictor OARs not overlapping the high dose CTV was limited to 50 Gy or less. Of note, patients with tumors involving the posterior pharyngeal wall, postcricoid space, or retropharyngeal nodes were not eligible for DO-IMRT. Median mean dose to the superior/medial constrictors (49.7 v 57.2 Gy) and the inferior constrictors (28.4 v 49.8 Gy) was significantly lower with DO-IMRT. This translated to significantly lower rates of grade 3+ dysphagia (5% v 15%) as well as higher composite scores on the MD Anderson Dysphagia Inventory in the DO-IMRT arm at 12 and even 24 months. There was a trend towards a lower rate of feeding tube placement in the DO-IMRT arm (33.9% v 52.7%), but this did not reach significance. There was no difference in locoregional recurrence between groups. On one level, reducing dose to the constrictors reduces toxicity. On a higher level, though, DARS further supports the idea that better IMRT treatment planning can meaningfully impact patient outcomes.
TBL: In the DARS trial, reducing mean dose to the pharyngeal constrictor muscles in patients receiving chemoradiation for oropharyngeal or hypopharyngeal cancer improved swallowing function after treatment. | Nutting, Lancet Oncol 2023
The Study: First off, what is dysphagia optimized IMRT (DO-IMRT)? DO-IMRT basically means delineating the pharyngeal constrictor muscles using MRI and constraining them during IMRT optimization. In the DARS trial, 112 patients with oropharyngeal or hypopharyngeal SCC requiring concurrent chemoradiation and bilateral neck irradiation were randomized to standard IMRT or DO-IMRT. In both arms, a 2-volume approach was used. Gross primary and nodal disease plus a 1cm CTV margin and 3-5mm PTV margin received 65 Gy in 30 fractions while an elective CTV covering the primary site and bilateral neck received 54 Gy in the same 30 fractions. In the DO-IMRT arm, the superior/middle and inferior constrictors were delineated on MRI. In addition to the standard OAR constraints, mean dose to the constrictor OARs not overlapping the high dose CTV was limited to 50 Gy or less. Of note, patients with tumors involving the posterior pharyngeal wall, postcricoid space, or retropharyngeal nodes were not eligible for DO-IMRT. Median mean dose to the superior/medial constrictors (49.7 v 57.2 Gy) and the inferior constrictors (28.4 v 49.8 Gy) was significantly lower with DO-IMRT. This translated to significantly lower rates of grade 3+ dysphagia (5% v 15%) as well as higher composite scores on the MD Anderson Dysphagia Inventory in the DO-IMRT arm at 12 and even 24 months. There was a trend towards a lower rate of feeding tube placement in the DO-IMRT arm (33.9% v 52.7%), but this did not reach significance. There was no difference in locoregional recurrence between groups. On one level, reducing dose to the constrictors reduces toxicity. On a higher level, though, DARS further supports the idea that better IMRT treatment planning can meaningfully impact patient outcomes.
TBL: In the DARS trial, reducing mean dose to the pharyngeal constrictor muscles in patients receiving chemoradiation for oropharyngeal or hypopharyngeal cancer improved swallowing function after treatment. | Nutting, Lancet Oncol 2023