Intensity Modulated Radiotherapy (IMRT) in locally advanced thyroid cancer: acute toxicity results of a phase I study.
OBJECTIVE
This phase 1 study was designed to determine the toxicity of accelerated fractionation IMRT in locally advanced thyroid cancer.


METHODS
Patients with high risk locally advanced thyroid cancer who required post-operative EBRT were recruited. A single-phase inverse-planned-simultaneous-boost was delivered by IMRT: 58.8 Gy/28F (daily) to the primary tumour and involved nodes and 50 Gy/28F to the elective nodes. Acute (NCICTCv.2.0) and late toxicity (RTOG and modified LENTSOM) was collected.


RESULTS
Thirteen patients were treated (7 medullary thyroid, 2 Hurthle cell and 4 well differentiated thyroid cancer). G3 and G2 radiation dermatitis rates were 38.5% and 31%; G3 and G2 mucositis rates 8% and 53% and G3 and G2 pain 23% and 54%. Thirty-one percentage required enteral feeding. G3 and G2 xerostomia rates were 0% and 31%. Recovery was seen, with 62% patients having dysphagia G< or =1 2 months after IMRT. Thirty percent of patients developed L'Hermitte's syndrome. No grade 4 toxicity was observed. No dose limiting toxicity was found.


CONCLUSIONS
Accelerated fractionation IMRT in this group of patients is feasible and safe. The acute toxicity appeared acceptable and early indicators of late toxicity moderate and similar to what would be expected with conventional RT. Longer follow up is required to quantify late side effects.
Urbano
Teresa Guerrero
TG
Head and Neck Unit, Royal Marsden Hospital, London, UK.
Clark
Catharine H
CH
Hansen
Vibeke N
VN
Adams
Elizabeth J
EJ
Miles
Elizabeth A
EA
Mc Nair
Helen
H
Bidmead
A Margaret
AM
Warrington
Jim
J
Dearnaley
David P
DP
Harmer
Clive
C
Harrington
Kevin J
KJ
Nutting
Christopher M
CM
D005260:Female; D006801:Humans; D008297:Male; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D013964:Thyroid Neoplasms / Q000532:radiotherapy*; D016896:Treatment Outcome