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Risk factors
- • neck irradiation in childhood;
- • endemic goitre;
- • Hashimoto’s thyroiditis (risk of lymphoma);
- • family or personal history of thyroid adenoma;
- • Cowden’s syndrome (macrocephaly, mild learning difficulties,carpet-pile tongue, with benign or malignant breastdisease);
- • familial adenomatous polyposis;
- • familial thyroid cancer;
- • obesity.
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Prognostic factors
- Age <10 & >40
- Male
- Histology
- - papillary > follicular(not if take age/extent into account)
- - papillary tall cell, columnar cell, degree of cellular differentiation,vascular invasion
- - follicular - widely invasive’ and ‘vascular invasion
- - Poorly differentiated and oncocytic follicular (Hurthle-cell) carcinomas poor prognosis
- Tumour extent
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Staging
- Primary tumour
- TX Primary tumour cannot be assessed
- T0 No evidence of primary tumour
- T1 Tumour ≤2 cm in greatest dimension limited to the thyroid
- T1a Tumour ≤1 cm, limited to the thyroid
- T1b Tumour >1 cm but ≤2 cm in greatest dimension, limited to thethyroid
- T2 Tumour >2 cm but ≤4 cm in greatest dimension, limited tothe thyroid
- T3 Tumour >4 cm in greatest dimension limited to the thyroidor any tumour with minimal extra-thyroidal extension(e.g. extension to sternothyroid muscle or perithyroidsoft tissues)
- T4a Tumour of any size extending beyond the thyroid capsule toinvade subcutaneous soft tissues, larynx, trachea, oesophagus, orrecurrent laryngeal nerve
- T4b Tumour invades prevertebral fascia or encases carotid artery ormediastinal vessels
- All anaplastic carcinomas are considered
- pT4 tumours
- T4a Anaplastic carcinoma limited to thyroidp
- T4b Anaplastic carcinoma extends beyond thyroid capsuleMultifocal tumours (≥2 foci) of all histological types should bedesignated (m), the largest focus determining the classification,e.g. pT2(m)
- Regional lymph nodes (cervical or upper mediastinal)
- NX Regional lymph nodes cannot be assessed
- N0 No regional lymph node metastasis
- N1 Regional lymph node metastasis
- N1a Metastases to Level VI (pretracheal, paratracheal, andprelaryngeal/Delphian lymph nodes)
- N1b Metastases to unilateral, bilateral, or contralateral cervical(Levels I, II, III, IV, or V) or retropharyngeal or superiormediastinal lymph nodes (Level VII)
- Distant metastases
- M0 No distant metastasis
- M1 Distant metastasis
- Residual tumour
- RX Cannot assess presence of residual primary tumour
- R0 No residual primary tumour
- R1 Microscopic residual primary tumour
- R2 Macroscopic residual primary tumour
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Staging
- Papillary/follicular thyroid tumours, <45 yrs
- Stage I: any T, any N, M0
- Stage II: any T, any N, M1
- Papillary/follicular thyroid tumours, >45 yrs
- Stage I: T1N0M0
- Stage II: T2N0M0
- Stage III: T3N0M0 or T1-3 N1aM0
- Stage IVA: T4a,anyN,M0 or T1-3,N1bM0
- Stage IVB: T4b anyN,M0
- Stage IVC: Any T, any N, M1
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Staging prognosis papillary/thyroid
- Stage 10-year relative survival (%)
- I 98.5
- II 98.8
- III 99.0
- IVA 75.9
- IVB 62.5
- IVC 63
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Post-operative risk stratification for risk of recurrence of DTC
- Low-risk patients
- • No local or distant metastases
- • All macroscopic tumour has been resected i.e. R0 or R1 resection(pathological definition)
- • No tumour invasion of loco-regional tissues or structures
- • The tumour does not have aggressive histology (tall cell, orcolumnar cell PTC, diffuse sclerosing PTC, poorly differentiatedelements), or angioinvasion
- Intermediate
- • Microscopic invasion of tumour into the perithyroidal soft tissues(T3) at initial surgery
- • Cervical lymph node metastases (N1a or N1b)
- • Tumour with aggressive histology (tall cell, or columnar cell PTC,diffuse sclerosing PTC, poorly differentiated elements) orangioinvasion
- High-risk patients
- • Extra-thyroidal invasion
- • Incomplete macroscopic tumour resection (R2)
- • Distant metastases (M1)
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Dynamic Risk Stratification:
definitions of response to initial therapy of DTC (9–12 months after total thyroidectomy with R0 resection and subsequent RRA)
- Excellent response - low risk
- • Suppressed and stimulated Tg < 1 lg/l
- • Neck US without evidence of disease
- • Cross-sectional and/or nuclear medicine imaging negative(if performed)
- Intermediate response - intermediate risk
- • Suppressed Tg < 1 lg/l & stimulated Tg ≥1 and <10 lg/l*
- • Neck US with nonspecific changesor stable sub centimetre lymph nodes
- • Cross-sectional and/or nuclearmedicine imaging with nonspecificchanges, although not completely normal
- Incomplete response - high risk
- Suppressed Tg≥1 lg/l* or stimulated Tg ≥ 10 lg/l*
- • Rising Tg values
- • Persistent or newly identified disease on cross-sectionaland/or nuclear medicine imaging
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Ultrasound
- Benign features
- spongiform or honeycomb appearance (micro-cystic spaces with thin walls, comprising >50% of the nodule)
- • purely cystic nodule
- • nodules with a cystic component containing colloid (hyper-echoic foci with a ‘ring-down’ sign)
- • egg shell type calcification around the periphery of a nodule
- • iso-echoic or (mildly) hyper-echoic in relation to the surrounding normal thyroid tissue and typically with a surrounding hypo-echoic halo
- • peripheral vascularity on colour flow or power Doppler
- Malignant features papillary/medullarya solid hypo-echoic (i.e. hypo-echoic relative to the normal thyroid tissue) nodule, which may contain hyper-echoic foci (i.e. microcalcification)
- • an irregular margin, intra nodular vascularity and absence of an associated halo
- • a ‘taller than wide’ shape referring to Anterior/Posterior (AP > Transverse (TR) diameter when imaged in the axial plane. AP diameter >TRdiameter increasing the likelihood of malignancy
- • an irregular or spiculated margin and a ‘taller than wide’ shape have both been shown to have good Positive Predictive Value for malignantnodules
- • egg shell type calcification around the periphery of a nodule with a broken calcified rim where there is extension beyond the calcified rim of ahypo-echoic
- Malignant features for follicular• typically hyper-echoic and homogenous in echo texture with a well defined halo
- • hypo-echogenicity and loss of the associated halo -associated with carcinoma
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Ultrasound grading
U1. Normal.
- U2. Benign:
- (a) halo, iso-echoic / mildly hyper-echoic
- (b) cystic change +/- ring down sign (colloid)(c) micro- cystic / spongiform
- (d & e) peripheral egg shell calcification
- (f) peripheral vascularity.
- U3. Indeterminate/Equivocal:
- (a) homogenous, hyper-echoic (markedly), solid, halo (follicular lesion).
- (b) ? hypo-echoic, equivocal echogenic foci, cystic change
- (c) mixed/central vascularity.
- U4. Suspicious:
- (a) solid, hypo-echoic (cf thyroid)
- (b) solid, very hypo-echoic (cf strap muscle)(c) disrupted peripheral calcification, hypo-echoic
- (d) lobulated outline
- U5. Malignant
- (a) solid, hypo-echoic, lobulated / irregular outline,micro-calcification. (? Papillary carcinoma)
- (b) solid, hypo-echoic, lobulated/irregular outline, globularcalcification (? Medullary carcinoma)
- (c) intra-nodular vascularity
- (d) shape (taller >wide) (AP>TR)
- (e) characteristic associated lymphadenopathy
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Thy prognosis
- Thy5 98–99%
- Thy 4 68–70%
- Thy3a 10%
- Thy 3f 30%
- Thy 2 <3%
- Thy 1 4-8%
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