Safety and efficacy of reduced dose and margins to involved lymph node metastases in locally advanced NSCLC patients. (February 2020)

• Record Type: Journal Article
• Authors: van Diessen, Judi N.A.; Kwint, Margriet; Sonke, Jan-Jakob; Walraven, Iris; Stam, Barbara; de Langen, Adrianus J.; Knegjens, Joost; Belderbos, José S.A.
• Is Part Of: Radiotherapy and oncology. Volume 143(2020)
• Page Start: 66
• Page End: 72
• Publication Date: 2020-02
• Subjects: Regional failures -- Radiotherapy dose reduction -- Locally advanced NSCLC; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2019.07.028
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: Two cohort-study of 308 locally advanced NSCLC-patients treated with (chemo)RT. Mediastinal lymph nodes received 66 Gy versus 58 Gy, while 66 Gy to primary tumour. Simultaneous reduction of PTV-margins due to online carina based CBCT-correction. The reduction-cohort showed less toxicity, comparable LRF and improved OS. Abstract: Background and purpose: (Chemo)Radiotherapy for locally advanced non-small lung cancer (LA-NSCLC) causes severe dysphagia due to the radiation dose to the mediastinal lymphadenopathy. Reducing the dose to the mediastinum and the margins to the planning target volume (PTV) might reduce severe toxicity rates. The results of both adaptations in LA-NSCLC patients receiving (chemo)radiotherapy were analysed. Materials and methods: 308 LA-NSCLC patients were included in an observational study. Both cohorts received hypofractionated RT (24 × 2.75 Gy) of 70 Gy (EQD210 ) to the primary tumour. The reference-cohort ( N = 170) received the same dose of 70 Gy (EQD210 ) to the involved lymph nodes, while the reduction-cohort ( N = 138) received 24 × 2.42 Gy, biologically equivalent to 60 Gy (EQD210 ). Furthermore, the patient-specific PTV-margins for both the primary tumour and lymph nodes were reduced by 2–3 mm in the reduction-cohort after implementing a carina based correction strategy. The effects on toxicity, regional failure and overall survival (OS) were assessed. Results: The acute grade 3 (G3) dysphagia and G3 pulmonary toxicity decreased significantly from 12.9% to 3.6% and 4.1% versus 0%, respectively. The regional failures were comparable: 5.9% versus 4.3% ( p = 0.546). The median OS was significantly different: 26 months (reference-cohort) versus 35 months (reduction-cohort). After correction for confounders, the association between the reduction-cohort and OS remained significant (HR 0.63 versus HR 0.70). Conclusion: A reduction in PTV-margins and dose from 70 Gy to 60 Gy to the involved lymph nodes in LA-NSCLC patients receiving (chemo)radiotherapy did not result in an increase in regional failures. Moreover, significantly lower acute toxicities and an improved OS were observed in the reduction-cohort.