- Simultaneous integrated boost of radiotherapy (SIB-RT) with chemotherapy was well tolerated with encouraging local control in a phase 1/2 trial of patients with unresectable, locally advanced esophageal cancer.
Why this matters
- Previous studies of dose escalation produced mixed results, but relied on outdated 2-dimensional radiotherapy.
- Single-group trial of chemoradiotherapy with 1 SIB-RT (50.4 Gy to subclinical areas at risk and 63.0 Gy to the gross tumor and involved nodes, all in 28 fractions).
- Patients received intensity-modulated photon therapy (39 patients) or proton therapy (7 patients).
- Funding: National Cancer Institute; Mabuchi Research Fund; family foundations; MD Anderson.
- There were no reported grade 4/5 acute or late toxic effects, and no cardiopulmonary toxic effects.
- There were 10 grade 3 toxic events: esophagitis (n=4), dysphasia (n=3), anorexia (n=3); 3 patients experienced late grade 3 events, all esophageal stricture.
- Cumulative local recurrence at 2 years, 33% (95% CI, 20%-46%).
- Median time to recurrence, 5 (range, 1-24) months.
- OS at 3 years, 29.1% (95% CI, 15.4%-42.7%).
- Median OS, 21.5 (range, 2.3-86.4) months.
- Compared with 97 historical patients who received standard doses of chemoradiotherapy:
- Recurrence risk: HR, 0.49; P=.03.
- OS overall: HR, 0.66; P=.02.
- OS, patients who did not undergo resection: HR, 0.58; P=.04.
- Historical control.