Simultaneous integrated boost of intensity‐modulated radiation therapy to Stage II‐III non‐small cell lung cancer with metastatic lymph nodes

Local tumor failure remains a major problem after radiation‐based nonsurgical treatment for unresectable locally advanced nonsmall cell lung cancer (NSCLC）and inoperable stage II NSCLC. The aim of this study was to evaluate the feasibility of simultaneous integrated boost of intensity‐modulated radiation therapy (SIB‐IMRT) to stage II‐III NSCLC with metastatic lymph nodes (ChiCTR 2000029304). Patients were diagnosed by pathology or PET‐CT. PTV was divided into two parts as follows, the PTV of primary tumor (PTVp) and the PTV of metastatic lymph nodes (PTVn). The radiotherapy doses were simultaneously prescripted 78 Gy (BED = 101.48 Gy) for PTVp and 60‐65 Gy (BED = 73.6‐81.25 Gy) for PTVn, 26f/5.2 weeks. Response was scored according to WHO criteria. Radiotherapy toxicity was scored according to RTOG criteria. Hematology and gastrointestinal toxicity were scored according to CTCAE1.0 criteria. A total of 20 patients were enrolled. Seventeen patients were diagnosed by pathology and three patients were diagnosed by PET‐CT. All patients were treated with SIB‐IMRT. The objective response rate (ORR) was 90%, with CR 25%, PR 65%, NC 10%, and PD 0%. Although radiotherapy toxicity was common, there were no grade ≥3, with radiation pneumonitis (10 cases), esophagitis (17 cases), and dermatitis (12 cases). The local control rates at 1, 3, and 5 years were 85%, 75%, and 70%, respectively. The overall survival（OS）and local progression‐free survival (LPFS) rates at 1, 3, and 5 years were 90%, 42.6%, and 35.5% and 84.4%, 35.5%, and 28.4%, respectively. SIB‐IMRT can significantly improve ORR and survival for stage II‐III NSCLC with metastatic lymph nodes, with high safety, and satisfactory efficacy. However, due to the limitation of small sample, these findings are needed to confirm by future trials with a larger sample size.