Vijay Karan Reddy, P (2015) Intensity-modulated radiotherapy of head and neck cancer aiming to reduce dysphagia: early dose–effect relationships of the swallowing structures. Masters thesis, Cancer institute (WIA), Chennai.
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Abstract
AIM: To elicit clinical advantages of sparing of swallowing structures, the pharyngeal constrictors (PC), glottic and supra-glottic larynx (GSL) and the esophagus. The primary end point of this study was to analyze dysphagia in patients treated with modified IMRT strategy and the secondary end point was to compare incidence and severity of dysphagia in a retrospective study where the same structures were not spared. MATERIAL AND METHODS: This is a prospective longitudinal study. The period of study was May 2013 to May 2014. A total of 26 patients, aged 16 to 70yrs being treated with concurrent chemo-radiation with cisplatin for nasopharyngeal and oropharyngeal carcinoma (Stage I-IV) with histology of SCC and NPC were considered for this study. The IMRT strategy used was optimized to spare the PC, GSL, and esophagus with a constraint to reduce the volume of these structures receiving more than 50Gy. The dose-effect relationship of these structures compared to clinical presentation was assessed. The clinical assessment of patients was done both subjectively with the help of the HNQOL instrument and objectively using penetration and aspiration score (PAS) in modified barium swallow. The clinical benefit of such a IMRT strategy was analyzed and compared to a retrospective group of patients in who the same swallowing structures were not given any dose constraints. RESULTS: Significant correlations were observed between barium swallow based dysphagia and the mean doses to the PC, GSL and Esophagus, as well as the partial volumes of these structures receiving 50–60 Gy; the highest correlations were associated with doses to the superior PC (p = 0.001). Significantly worse dysphagia was found post treatment (Pre vs Post – 34% vs 27%) 73% of the patients had no dysphagia and 3 (7.6%) of the patients were gastric tube dependent (1with aspiration). Compared to standard IMRT strategy – incidence of dysphagia significantly decreased (7.6% compared to 18%). CONCLUSION: These dose–volume-effect relationships provide initial IMRT optimization goals and motivate further efforts to reduce swallowing structures doses to reduce dysphagia and aspiration. When compared patients in whom the structures were not spared, there was a significant improvement in dysphagia.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Intensity-modulated radiotherapy; Head and Neck Cancer; Dysphagia; Swallowing Structures |
| Subjects: | MEDICAL > Radio Therapy |
| Depositing User: | Punitha K |
| Date Deposited: | 28 Mar 2018 08:00 |
| Last Modified: | 28 Mar 2018 08:00 |
| URI: | http://repository-tnmgrmu.ac.in/id/eprint/6709 |
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