Esophagitis intensity modulation.
Top Line: Does IMRT reduce esophageal toxicity in patients receiving palliative chest radiation for non-small cell lung cancer?
The Study: The goal of any palliative radiation therapy is to reduce disease-related symptoms while minimizing treatment-related toxicity. When delivering palliative radiation in the chest, the esophagus is the most likely source of treatment symptoms and also typically abuts the target volume. PROACTIVE was a randomized phase 3 trial of 90 patients receiving palliative radiation for advanced stage III/IV non-small cell lung cancer (NSCLC). They were randomized to conventional planning (think simple AP/PA opposed-field technique) or esophagus-sparing IMRT (ES-IMRT). To be eligible for randomization, their initial conventional plan had to include at least 5 cm of esophagus receiving >50% of the prescription dose. Most patients (60%) were prescribed 30 Gy in 10 fractions and the rest (40%) received 20 Gy in 5 fractions. In the IMRT arm, the esophagus was limited to a max dose (0.1 cc) of 80% of prescription. The average esophagus dose was slightly lower with IMRT (9.8 Gy v 10.2 Gy) as was maximum esophagus dose (23.8 Gy v 25.3 Gy). At 2 weeks after treatment, they just missed the mark in the primary outcome of patient-reported esophagus quality of life (p=0.06). In contrast, the rate of reported grade 2+ esophagitis was significantly lower with IMRT (2% v 24%), most prominent among those receiving 30 Gy (0% v 30%) compared to those receiving 20 Gy (6% v 17%). Considering that patients in the conventional arm were treated with AP/PA fields, it is likely that a slightly more sophisticated arrangement of 3D fields could reduce toxicity without requiring IMRT.
TBL: Compared to AP/PA fields, IMRT with the goal of sparing the esophagus significantly reduces the rate of grade 2+ esophagitis, most notable when delivering 30 Gy in 10 fractions, but does not significantly improve patient-reported esophageal quality of life. | Louie, JAMA Onc 2022