Maximal neutropenia during chemotherapy and radiotherapy is significantly associated with the development of acute radiation-induced dysphagia in lung cancer patients

Background: Acute dysphagia is a distressing dose-limiting toxicity after concurrent chemoradiation or high-dose radiotherapy for lung cancer. We therefore identified factors associated with the occurrence of acute dysphagia in lung cancer patients receiving radiotherapy alone or combined with chemotherapy. Patients and methods: Radiotherapy, chemotherapy and patient characteristics were analyzed using ordinal regression analysis as possible predictors for acute dysphagia (CTCAE 3.0) in 328 lung cancer patients treated with curative intent. Results: The most significant association was seen between the maximal grade of neutropenia during chemoradiation and dysphagia, with an odds ratio increasing from 1.49 [95% confidence interval (Cl) 0.63-3.54, P = 0.362] for grade 1-2 neutropenia to 19.7 (95% Cl 4.66-83.52, P < 0.001) for patients with grade 4 neutropenia. Twice-daily schedule, mean esophageal dose and administration of chemotherapy were significant predictive factors. By combining these factors, a high-performance predictive model was made. On an individual patient level, 64% of patients were correctly classified and only 1.2% of patients were misclassified by more than one grade. Conclusions: The maximal neutrophil toxicity during concurrent chemotherapy and radiotherapy is strongly associated with the development of acute dysphagia. A multivariate predictive model was developed.