Background and objective Twice-daily radiation concurrent with chemotherapy is one of the standard methods for limited-stage small cell lung cancer. hTe study was to evaluate the feasibility of chemotherapy concurrent with dose-escalating twice-daily radiotherapy by simultaneous integrated boost intensity-modulated radiation therapy (SIB-IMRT) approach in patients with limited-stage small cell lung cancer. Methods Patients with limited-stage small cell lung cancer were included, treated with twice-daily radiotherapy by SIB-IMRT concurrent with chemotherapy of etoposide plus cisplatin. Dose escalation was conducted by“classical”3+3 methods with three patients enrolled in each dose level. The therapeutic gross tumor volume (GTV) was treated according to three consecutive dose levels i.e., 45 Gy at 1.5 Gy twice daily, 50 Gy at 1.67 Gy twice daily and 54 Gy at 1.8 Gy twice daily. hTe planning target volume (PTV) received a dose of 45 Gy delivered in 30 fractions of 1.5 Gy. hTe primary endpoints were acute toxicities. hTe secondary endpoints included overall survival (OS), pro-gression-free survival (PFS) and loco-regional failure-free survival (LRFFS) at 1-year of follow-up. Results Twenty men and six women were included. hTe median age was 52 (30-68) months. 12 patients experienced grade 2 acute esophagitis, and 1 patient developed grade 3 acute esophagitis. Only 3 patients developed Grade 2 pneumonitis. Grade 3 or higher radiation-related pneumonia was not observed. None died of treatment-related causes. With median follow-up of 11.2 months (3.2-36.2 months), 1-year OS, PFS and LRFFS were 89.0%, 51.0%and 85.0%, respectively. Conclusion Dose escalation for twice-daily radiation concurrent with chemotherapy in LS-SCLC has been safely achieved up to 54 Gy for GTV using SIB-IMRT technique.

Background and objective Concurrent twice-daily radiotherapy with chemotherapy of EP regimen is one of the current standard treatments for limited-stage small cell lung cancer. However, the safely tolerated dose of standard chemotherapy for Chinese patients is not decided. hTis study was to evaluate the toxicity and the maximum tolerated dose (MTD) of etoposide and cisplatin concurrent with thoracic radiation therapy for patients with limited-stage small cell lung cancer. Methods Patients with histologically proven limited-stage small cell lung cancer (LS-SCLC) were eligible. hTe pa-tients underwent thoracic radiotherapy (45 Gy, 1.5 Gy bid, 30 fractions for 3 weeks) delivered concurrently with etoposide (100 mg/m2 iv, days 1-3) and cisplatin dose escalating from the two levels ( 70 mg/m2 and 75 mg/m2 on d1). hTe primary end-points were hematologic toxicities during treatment. hTe secondary endpoints were non-hematologic toxicities, overall survival (OS) and progression-free survival (PFS). According to Common Terminology Criteria for Adverse Events 4.0 (CTC-AE 4.0), maximum tolerant dosage (MTD) was deifned as the highest safely tolerated dose at which no more than one patient out of six experiences dose-limiting toxicity (Grades 4 hematologic), with the next higher dose having at least two out of six patients experience dose-limiting toxicity. Results From January 2013 to August 2016, 20 patients were enrolled in this study. hTe median age was 49.5 (30-68). Atfer the ifrst 6 patients were enrolled in Arm 1 (70 mg/m2 on d1), one patient had Grade 4 neu-tropenia. Another 14 patients were enrolled in Arm 2 (75 mg/m2 on d1), one patient had Grade 4 neutropenia. hTe MTD was determined to be etoposide (100 mg/m2 iv, d1-d3) and cisplatin dose (75 mg/m2 on d1). 4 patients had≥Grade 3 neutropenia and 1 patients had≥Grade 3 acute esophagitis in Arm 1. 10 patients had≥Grade 3 neutropenia and no patient had≥Grade 3 acute esophagitis in Arm 2. All patients with a median follow-up time was 9.0 months, median OS and PFS were not achieved, 1-year OS and PFS were 91%and 61%, respectively. Conclusion hTe MTD of RT with concurrent chemotherapy of EP regi-men for patients with LS-SCLC was etoposide (100 mg/m2 iv, d1-d3) and cisplatin dose (75 mg/m2 on d1).

Objective:To analyze the effectiveness and safety of the second course radiotherapy for unresectable colorectal cancer liver metastases.Methods:We retrospectively collected the data of 28 patients with unresectable colorectal cancer liver metastases who received the second course radiotherapy at Peking University Cancer Hospital and Institute from 2017 to 2023, to analyze the feasibility of re-irradiation.Results:For the 28 patients, the median follow-up time after re-irradiation was 20.2 months. The median time interval between the first- and second-course radiotherapy was 11.1 months. The median biologically effective doses of the first- and second-course radiotherapy were 100 Gy and 96 Gy, respectively. Stereotactic body radiotherapy was administered to 25 patients (89.3%) during the first course and 24 patients (85.7%) during the second course of radiotherapy. The mean equivalent dose in 2 Gy fractions to the normal liver was 10.1 Gy in the first-course radiotherapy and 7.9 Gy in the second-course radiotherapy. The complete response rate, partial response rate, and objective response rate after re-irradiation were 54.5%, 18.2%, and 72.7%, respectively. After re-irradiation, the 2-year cumulative local failure rate was 17.0% when calculated based on patients and 15.1% when calculated based on lesions, the 1-year progression-free survival rate was 27.4%, and the 3-year overall survival rate was 46.7%. The second-course radiotherapy was well tolerated, with most patients (75.0%) experiencing grade 1-2 acute adverse reactions and only one case (3.6%) experiencing grade 3 acute adverse events.Conclusions:Second course radiotherapy is an effective and safe treatment approach for selected patients with unresectable colorectal cancer liver metastases.