Large discrepancies between planned and actually delivered dose in IMRT of head and neck cancer. A case report.
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.
Piermattei
Angelo
A
UO Fisica Sanitaria, Dipartimento di Oncologia, Centro di Ricerca e Formazione ad Alta Tecnologia nelle Scienze Biomediche, Università Cattolica del Sacro Cuore, Campobasso, Italy. a.piermattei@rm.unicatt.it
Cilla
Savino
S
D'Onofrio
Guido
G
Grimaldi
Luca
L
Digesù
Cinzia
C
Macchia
Gabriella
G
Deodato
Francesco
F
Morganti
Alessio G
AG
D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002277:Carcinoma / Q000188:drug therapy / Q000532:radiotherapy*; D002945:Cisplatin / Q000008:administration & dosage; D003131:Combined Modality Therapy; D003680:Deglutition Disorders / Q000209:etiology; D004307:Dose-Response Relationship, Radiation; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D015182:Lymphatic Irradiation / Q000009:adverse effects* / Q000379:methods; D008207:Lymphatic Metastasis / Q000532:radiotherapy; D008297:Male; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy; D009929:Organ Size; D010614:Pharynx / Q000000981:diagnostic imaging / Q000528:radiation effects; D011832:Radiation Injuries / Q000209:etiology*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects* / Q000379:methods; D013280:Stomatitis / Q000209:etiology*; D014057:Tomography, X-Ray Computed; D014062:Tongue Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D015431:Weight Loss
D002945:Cisplatin; D005472:Fluorouracil