ert in thyroid cancer
DESCRIPTION
shortened for 15 minutes' talk at KSNHO 30th anniversary meeting on May 29th.TRANSCRIPT
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Technical Progress and Role of
External RT in Thyroid Cancer
Yong Chan Ahn, MD/PhD Dept. of Radiation Oncology
SMC/SKKU SOM
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In Treating Thyroid Cancer…
• Role of ERT has been proven in adjuvant,
salvage, as well as palliative settings.
• ERT, however, has been under-used than it
is needed, mainly in fear of annoying side
effects.
• With technical progress in ERT (IMRT,
IGRT) patients could get more benefit.
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1. Is ERT effective in thyroid cancer?
2. What are indications of ERT?
3. What are problems of ERT?
4. Can new RT techniques be answer?
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Case
• *** (F/76)
• CC: swallowing discomfort, hoarseness
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Definitive high dose ERT alone
’09/3/31~5/28: 70 Gy/35 fractions by 3D conformal RT
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’11/4/1 ’09/3/17
’11/10/11 ’09/3/20
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1. Is ERT effective in thyroid cancer?
2. What are indications of ERT?
3. What are problems of ERT?
4. Can new RT techniques be answer?
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IJROBP (2002)
• 1,057 DTC patients @ QEH (1960~1997)
842 patients (79.7%) had PTC
215 patients (20.3%) had FTC
• ERT (60 Gy/30 Fx’s) to thyroid bed and lymphatics if
gross LR disease in neck, extensive extrathyroidal
extension, extensive LN metastases
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Summary @ QEH
• ERT reduced LR failure risk.
• In 124 patients with gross
residual improved LR control
rate by ERT (56.2% vs 24%,
p=0.0019)
• ERT to improve LR control is
indicated in patients with
gross postoperative residual
disease.
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Clinical Endocrinology (2005)
• 729 DTC patients @ PMH (1958~1998)
’58~’71
(127)
’72~’85
(250)
’86~’98
(352)
Total
(729)
RAI Yes 59 (46%) 159 (64%) 310 (88%) 528 (72%)
No 68 (54%) 91 (36%) 42 (12%) 201 (28%)
RT Yes 71 (56%) 113 (45%) 134 (38%) 318 (44%)
No 56 (44%) 137 (55%) 218 (62%) 411 (56%)
Surgery Total 16 (13%) 95 (38%) 294 (84%) 405 (56%)
Subtotal 40 (32%) 61 (24%) 21 (6%) 122 (17%)
Lob 53 (42%) 86 (34%) 25 (7%) 164 (23%)
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Summary @ PMH
• ERT improved LRFR
and CSS in high-risk
patients.
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J Clin Endocrinol Metab (2011)
• Established role of EBRT in DTC:
• In adjuvant setting: extensive ETE, repeated cervical
nodal recurrence
• In definitive setting: local recurrence requiring
extensive ablative surgery
• Careful selection of high-risk patients is required.
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EBRT in DTC • American Thyroid
Association guideline:
– >45 years
– Grossly visible ETE
– High likelihood of
microscopic residual
disease
– Gross residual tumor in
whom further surgery or
RAI would likely be
ineffective
– Sequence of EBRT and
RAI depends on gross
residual disease volume and
likelihood of RAI
responsiveness
• British Thyroid Association
guideline :
– Gross evidence of local
tumor invasion at surgery
– Presumed significant
macro- or microscopic
residual disease
– Residual tumor fails to
concentrate sufficient
amounts of radioiodine
– Extensive pT4 disease
– >60 years
– Extensive extra-nodal
spread even without evident
residual disease
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EBRT in DTC • Medullary Thyroid Cancer:
– Further single institutional
data supports use of ERT
in improving local control
in highly selected patients
with MTC.
– However, ERT should be
reserved only in patients at
high risk of devastating
cervical recurrence
requiring extensive
ablative surgery.
• Anaplastic Thyroid Cancer:
– Extremely poor outcome.
– Improved local control
with concurrent ERT
(hyper-fractionation) and
taxanes.
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ERT as Palliative Tx
• Symptomatic skeletal metastases
• Brain metastases
• Hepatic metastases
• For relief of pressure symptoms by soft tissue
tumor in vital areas -- SVC syndrome
• Recurrent/metastatic tumor following RAI
• * ATC, MTC
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1. Is ERT effective in thyroid cancer?
2. What are indications of ERT?
3. What are problems of ERT?
4. Can new RT techniques be answer?
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Disadvantages of ERT
• Loco-regional Tx modality
• Not a selective Tx modality
• Long Tx duration (5~6 weeks)
• Dose-response relationship?
– Normal tissue tolerance limit have
been usually applied (50~60 Gy)
• Optimal RT target volume?
– Tumor bed + entire neck +/- upper mediastinum
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Common Side Effects of ERT
• Aerodigestive track:
– Swallowing discomfort, pain, voice change, dyspnea,
cough, sputum
• Skin and soft tissue:
– Dermatitis, lymphedema, fibrosis, joint stiffness, soft
tissue necrosis
• Glandular structures:
– Dry mouth (dental caries), dry eye
• Skeletal system:
– Osteonecrosis, chondronecrosis
• Others:
– Fatigue, anorexia, nausea, second cancer
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1. Is ERT effective in thyroid cancer?
2. What are indications of ERT?
3. What are problems of ERT?
4. Can new RT techniques be answer?
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From 2-D to 3-D
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Intensity Modulated RT
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2D
3D
IMRT
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Image Guided RT
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Individualized
Customized
Adaptive
New RT Techniques
Precise
Accurate
Reliable
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Therapeutic Ratio
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New RT Techniques
• Intensity Modulated RT (IMRT)
– LINAC-based: step & shoot;
sliding window; volumetric arc
– Helical Tomotherapy
• Image-guide RT (IGRT)
• Stereotactic Body RT (SBRT)
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RT Technique
• Combination of IMRT and IGRT may be
beneficial in reducing toxicity and improving
local control.
• IMRT and IGRT should ideally be employed
when treating thyroid cancer with EBRT.
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In Treating Thyroid Cancer…
• Role of ERT has been proven in adjuvant,
salvage, as well as palliative settings.
• ERT, however, has been under-used than it
is needed, mainly in fear of annoying side
effects.
• With technical progress in ERT (IMRT,
IGRT) patients could get more benefit.