Dosimetric Factors Associated With Long-Term Dysphagia After Definitive Radiotherapy for Squamous Cell Carcinoma of the Head and Neck
ABSTRACT Intensification of radiotherapy and chemotherapy for head-and-neck cancer may lead to increased rates of dysphagia. Dosimetric predictors of objective findings of long-term dysphagia were sought.
From an institutional database, 83 patients were identified who underwent definitive intensity-modulated radiotherapy for squamous cell carcinoma of the head and neck, after exclusion of those who were treated for a second or recurrent head-and-neck primary lesion, had locoregional recurrence at any time, had less than 12 months of follow-up, or had postoperative radiotherapy. Dosimetric parameters were analyzed relative to three objective endpoints as a surrogate for severe long-term dysphagia: percutaneous endoscopic gastrostomy (PEG) tube dependence at 12 months, aspiration on modified barium swallow, or pharyngoesophageal stricture requiring dilation.
Mean dose greater than 41 Gy and volume receiving 60 Gy (V(60)) greater than 24% to the larynx were significantly associated with PEG tube dependence and aspiration. V(60) greater than 12% to the inferior pharyngeal constrictor was also significantly associated with increased PEG tube dependence and aspiration. V(65) greater than 33% to the superior pharyngeal constrictor or greater than 75% to the middle pharyngeal constrictor was associated with pharyngoesophageal stricture requiring dilation.
Doses to the larynx and pharyngeal constrictors predicted long-term swallowing complications, even when controlled for other clinical factors. The addition of these structures to intensity-modulated radiotherapy optimization may reduce the incidence of dysphagia, although cautious clinical validation is necessary.
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ABSTRACT: Curative radiotherapy/chemo-radiotherapy for head and neck cancer (HNC) may result in severe acute and late side effects, including tube feeding dependence. The purpose of this prospective cohort study was to develop a multivariable normal tissue complication probability (NTCP) model for tube feeding dependence 6 months (TUBEM6) after definitive radiotherapy, radiotherapy plus cetuximab or concurrent chemoradiation based on pre-treatment and treatment characteristics.Radiotherapy and Oncology 10/2014; 113(1). DOI:10.1016/j.radonc.2014.09.013 · 4.86 Impact Factor
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ABSTRACT: Purpose To test the hypothesis that delineation of swallowing organs at risk (SWOARs) based on different guidelines results in differences in dose–volume parameters and subsequent normal tissue complication probability (NTCP) values for dysphagia-related endpoints. Materials and methods Nine different SWOARs were delineated according to five different delineation guidelines in 29 patients. Reference delineation was performed according to the guidelines and NTCP-models of Christianen et al. Concordance Index (CI), dosimetric consequences, as well as differences in the subsequent NTCPs were calculated. Results The median CI of the different delineation guidelines with the reference guidelines was 0.54 for the pharyngeal constrictor muscles, 0.56 for the laryngeal structures and 0.07 for the cricopharyngeal muscle and esophageal inlet muscle. The average difference in mean dose to the SWOARs between the guidelines with the largest difference (maxΔD) was 3.5 ± 3.2 Gy. A mean ΔNTCP of 2.3 ± 2.7% was found. For two patients, ΔNTCP exceeded 10%. Conclusions The majority of the patients showed little differences in NTCPs between the different delineation guidelines. However, large NTCP differences >10% were found in 7% of the patients. For correct use of NTCP models in individual patients, uniform delineation guidelines are of great importance.Radiotherapy and Oncology 04/2014; 111(1). DOI:10.1016/j.radonc.2014.01.019 · 4.86 Impact Factor
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ABSTRACT: Purpose This study aims to investigate a new planning method that avoids the match-line while maintaining larynx protection as in split field intensity-modulated radiation therapy (IMRT) and to evaluate the potential match-line dose variations with split IMRT. Methods/materials The new planning method, referred to as selective extended-field IMRT, selected anterior and anterior oblique fields to treat the entirety tumor volumes while restricting other IMRT fields from treating the tumor volumes below the larynx. Five patients with nasopharyngeal cancer, who underwent conventional extended-field IMRT, were replanned using the selective extended IMRT and split-field IMRT techniques. Results When treatment goals to the target volumes were met, selective extended-field IMRT resulted in an average mean larynx dose of 28.6 ± 1.4 Gy, as compared with 41.9 ± 10.6 and 29.3 ± 5.6 Gy for extended-field and split-field IMRT, respectively. For other organs at risk, there were no significant dose differences (p > 0.05) among three planning methods. Conclusions Selective extended-field IMRT achieves comparable tumor volume coverage as the conventional extended-field IMRT and comparable larynx sparing as split-field IMRT while eliminating field matching.06/2012; 1(2). DOI:10.1007/s13566-012-0015-1