1051. Large discrepancies between planned and actually delivered dose in IMRT of head and neck cancer. A case report
- Author
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Gabriella Macchia, Savino Cilla, Luca Grimaldi, Angelo Piermattei, Cinzia Digesù, G. D'Onofrio, Alessio G. Morganti, Francesco Deodato, Piermattei, Angelo, Cilla, Savino, D'Onofrio, Guido, Grimaldi, Luca, Digesù, Cinzia, Macchia, Gabriella, Deodato, Francesco, and Morganti, Alessio G
- Subjects
Male ,Cancer Research ,medicine.medical_treatment ,Planning target volume ,030218 nuclear medicine & medical imaging ,0302 clinical medicine ,Concurrent chemotherapy ,Antineoplastic Combined Chemotherapy Protocols ,Deglutition Disorder ,Radiation Injurie ,Recurrent Carcinoma ,Radiotherapy Dosage ,General Medicine ,Organ Size ,Combined Modality Therapy ,Tongue Neoplasms ,Oncology ,030220 oncology & carcinogenesis ,Lymphatic Metastasis ,Fluorouracil ,Human ,Simultaneous integrated boost ,03 medical and health sciences ,Weight Loss ,medicine ,Mucositis ,Humans ,Radiation Injuries ,Aged ,Stomatitis ,Antineoplastic Combined Chemotherapy Protocol ,Lymphatic Irradiation ,business.industry ,Radiotherapy Planning, Computer-Assisted ,Tumor shrinkage ,Head and neck cancer ,Carcinoma ,Lymphatic Metastasi ,Dose-Response Relationship, Radiation ,medicine.disease ,Weight Lo ,Stomatiti ,Radiation therapy ,Pharynx ,Radiotherapy, Intensity-Modulated ,Cisplatin ,Neoplasm Recurrence, Local ,Nuclear medicine ,business ,Deglutition Disorders ,Tomography, X-Ray Computed ,Tongue Neoplasm - Abstract
The case is reported of a patient with locally recurrent carcinoma of the tongue treated with intensity-modulated radiotherapy (IMRT) (simultaneous integrated boost) plus concurrent chemotherapy, who during the third week of radiotherapy developed grade 3 mucositis. Treatment was interrupted for 10 days until significant resolution of the symptoms. At the time of treatment resumption the patient showed 8% weight loss, and in vivo portal dose verification revealed large discrepancies between the computed and measured doses. A new CT scan showed marked tumor shrinkage and modifications to the critical structures. The comparison between the original plan and the hybrid IMRT showed a minimal dose increase in the new target volumes and a marked dose increase in the organs at risk. This case confirms the need for a robust quality assurance program when using IMRT, the feasibility and efficacy of in vivo dosimetry to detect significant discrepancies between planned and delivered dose, and the need to combine IMRT with 4-dimensional radiotherapy, at least for head and neck cancer.