BackgroundTo investigate the incidence of radiation esophagitis (RE) and tumor local control using esophagus sparing technique in locally advanced non-small cell lung cancer (LANSCLC) treated by simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) and concurrent chemotherapy.MethodsEighty-seven patients with stage IIIA/B NSCLC who received definitive SIB-IMRT and concurrent chemotherapy had been divided into two groups: 1.with esophagus sparing technique; 2.without esophagus sparing technique. Chi-square test was performed to compare sex, clinical stage, histology, concurrent chemotherapy, RE and nutrition status between two groups. T-test was used to compare the dosimetric parameters. Overall survival (OS) and loco-regional failure free survival (LRFS) were calculated by the Kaplan–Meier method and compared by a log-rank test.ResultsThere were 44 patients in the esophagus sparing group and 43 in the non-sparing group. The incidence of severe RE (Grade 3) was significantly lower in patients with esophagus sparing technique (p = 0.002). Patients in esophagus sparing group had better nutrition status (p = 0.045). With a median follow-up of 18 months (range 1–51 months), the 1-year, 2-year and 3-year OS of all the patients was 86.6, 65.4 and 43.7%. The 1-year, 2-year LRFS was 78.4, 65.9%. OS time (p = 0.301) and LRFS (p = 0.871) was comparable between two groups.ConclusionsEsophagus-sparing technique is an effective and essential method to limit RE in LANSCLC treated by SIB-IMRT and concurrent chemotherapy without compromising local control.
Background
This study aimed to quantify the dosimetric differences between the planned and delivered dose to tumor and normal organs in locally advanced non-small cell lung cancer (LANSCLC) treated with hypofractionated radiotherapy (HRT), and to explore the necessity and identify optimal candidates for adaptive radiotherapy (ART).
Methods
Twenty-seven patients with stage III NSCLC were enrolled. Planned radiation dose was 51Gy in 17 fractions with cone-beam CT (CBCT) acquired at each fraction. Virtual CT was generated by deformable image registration (DIR) of the planning CT to CBCT for dose calculation and accumulation. Dosimetric parameters were compared between original and accumulated plans using Wilcoxon signed rank test. Correlations between dosimetric differences and clinical variables were analyzed using Mann-Whitney U test or Chi-square test.
Results
Patients had varied gross tumor volume (GTV) reduction by HRT (median reduction rate 11.1%, range − 2.9-44.0%). The V51 of planning target volume for GTV (PTV-GTV) was similar between original and accumulated plans (mean, 88.2% vs. 87.6%, p = 0.452). Only 11.1% of patients had above 5% relative decrease in V51 of PTV-GTV in accumulated plans. Compared to the original plan, limited increase (median relative increase < 5%) was observed in doses of total lung (mean dose, V20 and V30), esophagus (mean dose, maximum dose) and heart (mean dose, V30 and V40) in accumulated plans. Less than 30% of patients had above 5% relative increase of lung or heart doses. Patients with quick tumor regression or baseline obstructive pneumonitis showed more notable increase in doses to normal structures. Patients with baseline obstructive atelectasis showed notable decrease (10.3%) in dose coverage of PTV-GTV.
Conclusions
LANSCLC patients treated with HRT had sufficient tumor dose coverage and acceptable normal tissue dose deviation. ART should be applied in patients with quick tumor regression and baseline obstructive pneumonitis/atelectasis to spare more normal structures.
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