Clinical efficacy and prognostic factors of simultaneous integrated boost intensity-modulated radiation therapy for esophageal squamous cell carcinoma

Abstract

Objective To evaluate the clinical efficacy and analyze relevant prognostic factors of simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) for esophageal squamous cell carcinoma. Methods A total of 101 patients diagnosed with esophageal squamous cell carcinoma received SIB-IMRT from 2009 to 2015. The prescribed dose of PTV was 5 040 cGy/28 times (180 cGy/time) and the dose for planning gross tumor volume (PGTV) was 6 020 cGy/28 times (215 cGy/time) or 6 160 cGy/28 times (220 cGy/time) simultaneously. The total treatment time was 5.5 weeks (once a day, 5 times a week). The adverse events, mode of treatment failure, l-, 3-and 5-year local control (LC) and overall survival (OS) rates were observed. Results The quantity of patients who completed the 1-, 3-and 5-year follow-up was 101, 84 and 45, respectively. The 1-, 3-and 5-year LC rates were 81.6%, 70.4% and 68.4%, respectively. The 1-, 3-and 5-year OS rates were 72.3%, 49.4% and 45.2%, respectively. The median survival time was 36 months. Univariate and multivariate analyses showed that clinical staging (stage Ⅰ/Ⅱ/Ⅲ) and tumor response (complete remission/ partial remission/no remission) were the prognostic factors of OS (P=0.016, 0.000, 0.005, 0.000). There were no significant differences in the LC and OS between the two groups of 215 cGy and 220 cGy (P=0.283, 0.951). The incidence rates of grade 1, 2, 3 acute pneumonitis were 10.9%(11/101), 2.0%(2/101) and 2.0%(2/101), respectively. The incidence rates of grade 1, 2, 3 acute esophagitis were 63.4%(64/101), 10.9%(11/101) and 4.0%(4/101), respectively. No acute esophageal perforation or hemorrhage occurred. Five patients experienced late pneumonitis (two died). One case developed late lemostenosis, two cases developed esophageal perforation and hemorrhage, and two patients experienced esophageal hemorrhage. The patients treated with a fractionated dose of 220 cGy had a higher incidence rate of acute pneumonitis and upper gastrointestinal adverse reactions than those receiving 215 cGy (P=0.062, 0.024). The local failure and recurrence accounted for 62.5% of all treatment-related failures. Conclusions SIB-IMRT yields high long-term clinical efficacy and tolerable adverse events in the treatment of esophageal squamous cell carcinoma. Compared with the dose of 215 cGy, the fractionated dose of 220 cGy fails to improve LC and OS rates, whereas enhances the risk of adverse events. The clinical staging and short-term clinical efficacy are the prognostic factors of survival rate. Key words: Esophageal neoplasm/intensity-modulated radiotherapy; Intensity-modulated radiotherapy; Simultaneous integrated boost; Prognosis