Patterns of Dose Escalation Among Patients With Esophageal Cancer Undergoing Definitive Radiation Therapy: 2006-2016

Purpose: Although single-institution series suggest potential benefit to dose escalation in definitive radiation therapy for esophageal cancer, randomized trials including intergroup-0123 and the recently presented A Randomized Trial of Dose Escalation in definitive Chemoradiotherapy for patients with Oesophageal cancer (ARTDECO) trial showed no improvement in outcomes with higher radiation therapy dose. As such, there may be significant variation in radiation dose for definitive treatment of esophageal cancer. Methods and Materials: The National Cancer Database was used to identify patients who received a diagnosis of nonmetastatic T2+ esophageal cancer between 2006 and 2016 who did not receive definitive surgery and were treated with chemotherapy and radiation therapy doses between 41.4 and 74 Gy. Multivariable logistic regression defined adjusted odds ratios (AORs) of receipt of >50.4 Gy, including year of diagnosis (2006-2013 vs 2014-2016) ∗ histology (squamous cell carcinoma [SCC] vs adenocarcinoma) and year of diagnosis (2006-2013 vs 2014-2016) ∗ disease site (cervical esophagus vs noncervical esophagus) interaction terms, to assess whether the effect of diagnosis year on dose varied by histology and disease site, respectively. Results: Among 14,517 patients, the most common dose was 50.4 Gy, used for 6955 (47.9%) patients. Dose escalation above 50.4 Gy was observed in 4440 (30.6%) patients and declined by year, from 42.2% in 2006 to 23.5% in 2016. Patients with SCC versus adenocarcinoma had higher odds of dose escalation (39.3% vs 23.8%; AOR 1.46; P < .001), as did those with cervical esophageal primaries versus other primary sites (54.9% vs 27.4%; AOR 2.51; P < .001). The effect of later diagnosis year was greater for adenocarcinoma than for SCC (pint = 0.001, AOR 0.54, P < .001 vs AOR 0.71, P < .001) and significant for noncervical esophagus but not cervical esophagus (pint <0.001, AOR 0.56, P < .001 vs AOR 0.95, P = .616). Conclusions: Dose escalation in definitive chemoradiotherapy for esophageal cancer declined over time, particularly for adenocarcinoma histology and noncervical primary site. Given the recent results of ARTDECO, our findings can serve as a benchmark from which to measure future shifts in practice patterns.