Background
Immunotherapy has made significant advances in the treatment of extensive-stage small-cell lung cancer (ES-SCLC), but data in combination with radiotherapy are scarce. This study aims to assess the safety and efficacy of chemoimmunotherapy combined with thoracic radiotherapy in patients with ES-SCLC.
Methods
This single-center retrospective study analyzed patients with ES-SCLC who received standard platinum–etoposide chemotherapy combined with atezolizumab or durvalumab immunotherapy as induction treatment, followed by consolidative thoracic radiotherapy (CTRT) before disease progression in the first-line setting. Adverse events during radiotherapy with or without maintenance immunotherapy and survival outcomes were assessed.
Results
Between December 2019 and November 2021, 36 patients with ES-SCLC were identified to have received such treatment modality at one hospital. The number of metastatic sites at diagnosis was 1–4. The biological effective dose of CTRT ranged from 52 to 113 Gy. Only two patients (6%) developed grade 3 toxic effect of thrombocytopenia, but none experienced grade 4 or 5 toxicity. Four patients developed immune-related pneumonitis during the induction treatment period but successfully completed later CTRT. The rate of radiation-related pneumonitis was 8% with grades 1–2 and well tolerated. The median progression-free survival (PFS) was 12.8 months, but the median overall survival (OS) was not determined. The estimated 1-year OS was 80.2% and 1-year PFS was 53.4%.
Conclusions
Immunotherapy combined with CTRT for ES-SCLC is safe and has ample survival benefit.
Background
Radiation-induced brainstem necrosis (RIBN) is a late life-threatening complication that can appear after treatment in patients with nasopharyngeal carcinoma (NPC). However, the relationship between RIBN and radiation dose is not still well-defined.
Methods
During January 2013 and December 2017, a total of 1063 patients with NPC were treated at Sichuan cancer hospital with IMRT. A total of 479 patients were eligible for dosimetric analysis. Dosimetric parameters of the RIBN, Dmax(the maximum dose), D0.1c (maximum average dose delivered to a 0.1-cc volume), D1cc, D2cc, D3cc, D5cc, D10cc and Dmean (mean does) were evaluated and recorded. ROC curve was used to analyze the area under curve (AUC) and cutoff points. Logistic regression for screening dose-volume parameter and logistic dose response model were used to predict the incidence of brainstem necrosis.
Results
Among the 479 patients with NPC, 6 patients were diagnosed with RIBN, the incidence of RIBN was 1.25% (6/479), and the median time to RIBN after treatment was 28.5 months (range 18–48 months). The dose of the brainstem in patients with RIBN were higher than that in patients without necrosis. ROC curve showed that the area under the curve (AUC) of Dmax was the largest (0.987). Moreover, logistic stepwise regression indicated that Dmax was the most important dose factor. The RIBN incidence at 5% over 5 years (TD5/5) and 50% incidence over 5 years (TD50/5) was 69.59 Gy and76.45 Gy, respectively.
Conclusions
Brainstem necrosis is associated with high dose irritation. Dmax is the most significant predictive dosimetric factor for RIBN. Dmax of brainstem should be considered as the dose limitation parameter. We suggest that the limitation dose for brainstem was Dmax < 69.59 Gy.
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