Thyroid Cancer FRCR CO2A Flashcards
1
Q
What is the overall prognosis of thyroid cancer related to?
A
The histological type
Well-differentiated thyroid cancer (papillary and follicular) has the best prognosis, while anaplastic carcinoma has a very poor prognosis.
2
Q
What are the most common types of thyroid carcinomas?
A
Papillary, follicular, medullary, and anaplastic
These types are listed in order of frequency.
3
Q
What age group is thyroid cancer uncommon in?
A
Patients under the age of 25
4
Q
What is the best-documented risk factor for thyroid cancer?
A
Radiation exposure
5
Q
What types of thyroid tumours are rarer than carcinomas?
A
Thyroid lymphomas and sarcomas
6
Q
Which type of thyroid cancer progresses rapidly and has a poor prognosis?
A
Anaplastic carcinoma
7
Q
What are the types of thyroid tumours categorized into?
A
Benign, malignant primary, and malignant secondary
8
Q
What influences the relative proportions of differentiated thyroid cancer in a geographic area?
A
Dietary iodine intake
The proportion of follicular cancers increases where there is dietary iodine deficiency.
9
Q
What is a controversial area in the management of differentiated thyroid cancer?
A
Extent of surgery, indications for radioiodine ablation and radiotherapy
10
Q
What type of evidence is limited in guiding management for differentiated thyroid cancer?
A
Prospective randomised controlled studies
11
Q
Fill in the blank: Well-differentiated thyroid cancer includes _______.
A
Papillary and follicular
12
Q
A
13
Q
What is the origin of the thyroid gland?
A
The thyroid develops from an endodermal outgrowth from the midline of the pharyngeal floor
14
Q
What structure does the thyroid gland form during its development?
A
The thyroglossal duct
15
Q
How many lobes does the thyroid gland consist of?
A
Two lobes connected by the isthmus
16
Q
What is the typical weight range of the thyroid gland?
A
15–20 g
17
Q
Where can the apex of each thyroid lobe reach?
A
Up to the oblique line on the thyroid cartilage
18
Q
At what level does the base of the thyroid gland lie?
A
At the level of the fourth or fifth tracheal ring
19
Q
Which tracheal rings does the isthmus of the thyroid gland overlie?
A
The second, third, and fourth tracheal rings
20
Q
What is often present and extends up from the isthmus of the thyroid gland?
A
The pyramidal lobe
21
Q
What is related to the posterior aspect of each lobe of the thyroid gland?
A
The four parathyroid glands
22
Q
Where are the parathyroid glands located in relation to the thyroid gland?
A
Inside the fascial capsule of the thyroid gland behind the middle and inferior parts
23
Q
Which nerve is closely related to the thyroid gland?
A
The recurrent laryngeal nerve
24
Q
Where does the recurrent laryngeal nerve lie in relation to the thyroid gland?
A
In the groove between the trachea and the oesophagus
25
What are the first-station nodes associated with the thyroid gland?
* Paralaryngeal
* Paratracheal
* Prelaryngeal
26
What is the central neck compartment bounded by superiorly?
The hyoid
27
What structures bound the central neck compartment laterally?
Carotid arteries
28
What structure bounds the central neck compartment anteriorly?
The superficial layer of deep cervical fascia
29
What bounds the central neck compartment posteriorly?
The deep layer of deep cervical fascia
30
At what level is the inferior border of the central neck compartment located?
At the level of the innominate artery
31
What is the majority composition of the thyroid gland?
Follicles filled with colloid
## Footnote
Follicles are the functional units of the thyroid gland.
32
What type of cells are parafollicular or C cells?
Cells that originate from the neural crest and produce calcitonin
## Footnote
Calcitonin is involved in calcium homeostasis.
33
What percentage of thyroid cells do parafollicular or C cells account for?
0.1%
## Footnote
This indicates they are a minor component of the thyroid gland.
34
Where are parafollicular or C cells located in the thyroid gland?
At the junction of the upper and lower two-thirds of the lobes
## Footnote
This location is crucial for their function and interaction with other thyroid cells.
35
From which part of the thyroid can tumors arise?
Follicular epithelium, parafollicular or C cells, non-epithelial stromal elements
## Footnote
Different types of tumors include papillary, follicular, anaplastic, and medullary types.
36
Fill in the blank: Tumors can arise from the _______ epithelium.
follicular
## Footnote
Follicular tumors are one of the common types of thyroid tumors.
37
True or False: Para-follicular cells are located inside the follicles of the thyroid gland.
False
## Footnote
Parafollicular or C cells are located outside the follicles.
38
What is papillary microcarcinoma defined as?
A papillary cancer ≤ 10 mm
## Footnote
Papillary microcarcinoma is often discovered incidentally.
39
What are incidental carcinomas?
A tumour focus found solely on histological examination of the thyroid gland
## Footnote
No abnormality detected preoperatively.
40
Are papillary cancers often multifocal?
Yes, frequency of multifocality depends on method of pathological assessment
## Footnote
Multifocality is a common characteristic of papillary cancers.
41
What are typical features of papillary cancers?
Orphan Annie nuclei and psammoma bodies
## Footnote
These features are commonly observed in papillary thyroid carcinoma.
42
Which variants of papillary cancer are more aggressive?
Tall cell, columnar, and diffuse sclerosing variants
## Footnote
These variants have a higher tendency for aggressive behavior.
43
What is a limitation of cytology in diagnosing follicular cancer?
Cytology cannot distinguish adenomas from malignant tumours
## Footnote
This makes definitive diagnosis with FNAC impossible.
44
What is required for histological confirmation of follicular cancers?
Invasion of the capsule and/or blood vessels
## Footnote
This is necessary to confirm malignancy in follicular cancers.
45
What is the typical nature of Hürthle cell/oxyphil tumours?
The majority are benign; if malignant, usually well differentiated
## Footnote
They produce thyroglobulin but may fail to take up radioiodine.
46
From what do anaplastic carcinomas arise?
From follicular cells
## Footnote
They can arise de novo or from differentiated thyroid cancer.
47
What cells does medullary thyroid cancer (MTC) arise from?
Parafollicular cells or C cells
## Footnote
These have a neural crest/neuroendocrine origin.
48
What substances can medullary thyroid cancer secrete?
Calcitonin and carcinoembryonic antigen (CEA)
## Footnote
Amyloid may also be present in MTC.
49
How are hereditary tumours with MEN 2 and MEN 3 inherited?
In an autosomal dominant fashion
## Footnote
They are associated with a germline mutation in the RET proto-oncogene.
50
What is a characteristic of tumours arising with MEN syndromes?
Often bilateral and multicentric
## Footnote
C cell hyperplasia may also be present.
51
What is the origin of many Non-Hodgkin lymphomas?
Derived from mucosa-associated lymphoid tissue (MALT)
## Footnote
These lymphomas tend to be of low grade with a tendency for distant relapse.
52
Can high-grade lymphomas occur in Non-Hodgkin lymphoma?
Yes
## Footnote
High-grade lymphomas are also a possibility.
53
Is there currently a screening programme for the general population regarding thyroid cancer?
No
54
Who should seek genetic advice related to thyroid cancer?
Individuals with a strong family history of thyroid cancer or association with other cancers
55
Which patients should be referred for germline RET mutation testing?
All newly diagnosed patients with MTC, regardless of family history
56
What exons are tested in germline RET mutation testing for MTC?
Exons 10, 11 and 13–15
57
What surgical procedure is recommended for adult gene carriers of RET mutations?
Total thyroidectomy with central lymph node dissection
58
What condition must be excluded before performing a total thyroidectomy on adult gene carriers?
Phaeochromocytoma
59
At what age should child gene carriers of MEN 3 typically undergo surgery?
At an early age, often soon after the first year
60
By what age do children carrying MEN 2 mutations typically have surgery?
By the age of 3
61
What is the purpose of surgery for children carrying MEN 2 mutations?
To establish them on thyroxine therapy by school age
62
What are the two main subtypes of thyroid tumors mentioned?
Papillary and follicular
## Footnote
These subtypes are classified based on age and specific characteristics.
63
How are stage groupings assigned for thyroid tumors?
Based on the patient's age: under 45 or 45 years and older
## Footnote
This classification impacts treatment and prognosis.
64
What stage are all cases involving patients younger than 45 years classified as?
Stage I or II
## Footnote
This applies regardless of TNM categories.
65
What stage is assigned to all cases of anaplastic or undifferentiated thyroid cancer?
Stage IV
## Footnote
This stage indicates a more advanced disease.
66
67
What percentage of all malignancies does differentiated thyroid cancer represent?
< 1%
## Footnote
Differentiated thyroid cancer is the most common endocrine malignancy.
68
In 2011, how many new cases of thyroid cancer were reported in the UK?
2727 new cases
## Footnote
28% in men and 72% in women.
69
What was the crude incidence rate of thyroid cancer in the UK per 100,000 females?
6 per 100,000 females
## Footnote
The rate for males was 2 per 100,000.
70
Since when have thyroid cancer incidence rates been increasing in the UK?
Since the mid-1970s
## Footnote
The rise has been more marked in women.
71
What are some suggested reasons for the increase in thyroid cancer incidence?
* Increasing use of ultrasound to investigate thyroid nodules
* Detection of subclinical disease
* Better and more frequent diagnostic activity
## Footnote
The exact reason for the increase remains unclear.
72
What are the main risk factors for differentiated thyroid cancer?
* Increasing age
* Female gender
* History of neck irradiation in childhood
* Nuclear fallout
* Endemic goitre
* Gardner’s syndrome
* Cowden’s syndrome
* Familial adenomatous polyposis (FAP)
* Familial differentiated thyroid cancer
* Turcot’s syndrome
* Carney complex
73
List some clinical presentations of thyroid cancer.
* Asymptomatic thyroid nodule or cervical node
* Sense of fullness/pressure in neck
* Stridor, dysphonia, dysphagia, odynophagia, cough
* Unexpected finding after thyroidectomy for presumed benign disease
* Unexpected finding on PET-CT scan
* Distant metastases – dyspnoea, haemoptysis, bone pain
74
What is the primary method for diagnosing thyroid cancer?
Neck ultrasound and thyroid nodule FNAC
## Footnote
FNAC is categorized by the Royal College of Pathologists.
75
What does Th y1 indicate in FNAC categorization?
Non-diagnostic
## Footnote
This includes poor operator technique and insufficient colloid and epithelial cells.
76
What does Th y5 indicate in FNAC categorization?
Diagnostic of malignancy
## Footnote
The likelihood of malignancy increases with increasing Th y category.
77
What ultrasound characteristics suggest malignancy in thyroid nodules?
* Solid hypo-echoic nodule
* Hyper-echoic foci (microcalcification)
* Irregular margin
* Intranodular vascularity
* Absence of an associated halo
* Irregular margin and 'taller than wide' shape
78
What imaging techniques should patients with locally advanced thyroid cancer undergo?
CT or MRI of neck and chest
## Footnote
This assesses local disease extent and plans surgical treatment.
79
What is serum thyroglobulin, and why is it significant?
A glycosylated protein secreted by thyroid cells
## Footnote
It is a key substrate for thyroid hormone biosynthesis and is TSH-dependent.
80
What is the primary treatment strategy for differentiated thyroid cancer?
Combination of surgery, radioiodine, and TSH-suppressive doses of thyroxine
## Footnote
External beam radiotherapy may also play a role in advanced cases.
81
What are the indications for hemithyroidectomy?
* Differentiated thyroid cancers (DTCs) ≤ 1 cm
* Tumor does not extend beyond thyroid capsule
* No evidence of multifocal/bilateral disease, lymph node metastases, or vascular invasion
82
What are the advantages of total thyroidectomy?
* Ability to follow up using serum Tg
* Eliminates risk of second cancer focus
* Reduces risk of local recurrence
83
What is the recommended follow-up for patients after thyroid cancer treatment?
* Assess serum TSH suppression
* Adjust TSH levels based on treatment response
## Footnote
Criteria include incomplete response, indeterminate response, and excellent response.
84
What dietary preparation is required before radioiodine remnant ablation?
Low-iodine diet for 1–2 weeks
## Footnote
Iodinated contrast and certain medications should also be avoided.
85
What is the role of recombinant human TSH (rhTSH) in thyroid cancer treatment?
Facilitates effective remnant ablation and improves quality of life
## Footnote
It reduces radiation exposure to normal tissues.
86
What is rhTSH?
Recombinant human thyroid-stimulating hormone
## Footnote
rhTSH is used for thyroid hormone withdrawal for patients with differentiated thyroid cancer (DTC)
87
What are the benefits of using rhTSH compared to thyroid hormone withdrawal (THW)?
Better quality of life and reduced radiation exposure to normal tissues
## Footnote
rhTSH has not been evaluated in randomized controlled trials for all patient scenarios.
88
What are the recommended characteristics for using rhTSH in 131 I ablation?
T1 to T3, N0 or NX or N1, M0 and R0
## Footnote
R0 indicates no microscopic residual disease.
89
What is the administration protocol for rhTSH injections?
0.9 mg deep i.m. injections on days 1 and 2, with radioiodine on day 3
## Footnote
Thyroglobulin is measured on day 5.
90
What are common side effects of rhTSH?
Flu-like myalgia, mild nausea, headache
## Footnote
Possible stimulation of metastases may occur.
91
What is the alternative to rhTSH if it is unavailable?
Liothyronine
## Footnote
Liothyronine should be withdrawn 14 days before RRA or therapy.
92
What is the recommended activity of 131 I for patients with T1–2, N0 with R0 resection?
1.1 GBq
## Footnote
Higher activities for T3 and/or N1 disease should be decided by the MDT.
93
What is the recommended activity of 131 I for persistent neck disease or metastatic disease?
3.7–5.5 GBq
## Footnote
This is for patients with known residual local disease.
94
What imaging method is used to determine radioiodine uptake after treatment?
Whole-body radioiodine scans
## Footnote
SPECT-CT imaging may help localize uptake accurately.
95
What are common side effects of radioiodine treatment?
Neck discomfort, altered taste, nausea, sialoadenitis, dry mouth, radiation cystitis, gastritis
## Footnote
Male fertility may be affected; sperm storage considered for high-risk cases.
96
What precautions should be taken regarding radiation protection after radioiodine therapy?
Exclude pregnancy, discontinue breastfeeding 8 weeks prior, avoid pregnancy for 6 months
## Footnote
Patients should also double flush toilets and wash clothing separately.
97
How is remnant ablation success assessed?
Stimulated Tg and specialized neck ultrasound
## Footnote
No need for a diagnostic 131 I whole-body scan.
98
What are the categories for dynamic risk stratification after ablation?
Excellent response, indeterminate response, incomplete response
## Footnote
Each category requires different follow-up and treatment decisions.
99
What is the main indication for external beam radiotherapy in thyroid cancer?
Unresectable disease, non-iodine-avid disease, gross local invasion
## Footnote
It is rarely used due to proximity to critical structures.
100
What is the recommended dose for CTV1 in IMRT for thyroid cancer?
63–66 Gy in 30 daily fractions
## Footnote
This is for regions of grossly positive margins or gross residual disease.
101
What is the role of chemotherapy in thyroid carcinoma treatment?
Not routinely used; largely superseded by targeted therapies
## Footnote
Doxorubicin was previously used with limited response rates.
102
What are the most effective targeted therapies for symptomatic progressive metastatic thyroid cancer?
Sorafenib and lenvatinib
## Footnote
Sorafenib increases progression-free survival by approximately 5 months.
103
What is the recommended management for thyroid cancer diagnosed during pregnancy?
Surgery is the treatment of choice if rapid growth or significant lymph node metastases are present
## Footnote
Thyroidectomy is safer in the second trimester.
104
What is the recurrence rate of thyroid cancer in children compared to adults?
Higher in children, especially young children
## Footnote
Fewer than 10% of children die from their disease.
105
What is the treatment protocol for solitary metastases from thyroid cancer that do not concentrate radioiodine?
Surgical resection if possible, followed by 131 I therapy
## Footnote
The 5-year post-metastasectomy survival is 40–50%.
106
What is the recommended dose for radioiodine therapy at 6- to 12-month intervals?
7–7.4 GBq
## Footnote
There is no maximum cumulative dose, but monitoring of FBC and renal function is necessary.
107
What is the survival rate at 5 years post-metastasectomy for solitary metastases that can be resected?
40–50%
## Footnote
This applies when the metastases do not concentrate iodine.
108
What can falsely elevate serum thyroglobulin (Tg) levels?
Tg antibodies
## Footnote
These antibodies may not always be measurable.
109
What is more significant than a single elevated serum Tg result?
A serial rise in Tg or thyroglobulin antibody titre
110
What imaging modalities are considered when neck ultrasound is negative and Tg is positive?
* chest CT (without iodinated iv contrast if further 131 I planned)
* neck MRI
* bone scan
* spine MRI
* 18 fluoro-deoxy-glucose (FDG)-positron emission tomography (PET)
111
What effect do thyroxine withdrawal or rhTSH administration have on 18 FDG-PET-CT scan?
They increase the sensitivity of the scan
112
True or False: Patients with positive 18 FDG-PET scan have a better 3-year survival compared to those who are negative.
False
## Footnote
Positive 18 FDG-PET scan indicates markedly reduced 3-year survival.
113
What is the typical activity range for empirical 131 I therapy?
3.7–7.4 GBq, usually 5.5 GBq
114
What are the aims of follow-up for thyroid cancer patients?
* Detect recurrence early
* Monitor TSH suppression
* Detect and manage hypocalcaemia
115
What is the duration of follow-up recommended for thyroid cancer patients?
Life-long
116
What are the most important predictors of outcomes in well-differentiated thyroid cancer?
* Patient’s age
* Tumour size
* Tumour grade
* Extrathyroid spread
* Distant metastases
117
What is the preferred tool for assessing individual risk of relapse in thyroid cancer?
Dynamic risk stratification
118
What is the typical age range for the sporadic form of medullary thyroid cancer (MTC)?
Fifth and sixth decades of life
119
What is the female-to-male incidence ratio for medullary thyroid cancer?
1.5:1
120
What mutations are associated with MEN types 2 and 3 in relation to medullary thyroid cancer?
Mutations in the RET proto-oncogene
121
What is the mainstay treatment for medullary thyroid cancer?
Surgery
122
What should be done if postoperative MTC patients have serum calcitonin levels ≥ 150 pg/mL?
* Undergo neck US
* Additional imaging to look for distant metastases
123
What is the median survival time for patients with anaplastic thyroid cancer?
6 months from development of symptoms
124
What is the typical treatment approach for anaplastic thyroid cancer?
Palliative treatment for most patients
125
What types of thyroid lymphoma account for the majority of cases?
* Diffuse large B-cell lymphoma (approx. 70%)
* MALT lymphoma (approx. 25%)
126
What is the role of external beam radiotherapy in the treatment of anaplastic thyroid cancer?
It is unclear, as some studies report improved local control while others report no difference or detrimental effects.
127
What role does chemotherapy play in the treatment of medullary thyroid cancer?
Rarely helpful unless there is rapidly progressive symptomatic disease
128
What is the prognosis for patients with thyroid lymphoma?
The prognosis depends on the stage of disease. The majority of patients present with localized disease and have a favorable prognosis.
129
What are the most common types of thyroid lymphoma?
* Diffuse large B-cell lymphoma (approx. 70%)
* MALT lymphoma (approx. 25%)
* Follicular lymphoma
* Classic Hodgkin lymphoma
130
What is the female-to-male incidence ratio for thyroid lymphoma?
3:1, which increases above 60 years.
131
What is the typical age range for the occurrence of thyroid lymphoma?
60–65 years.
132
What percentage of patients with thyroid lymphoma present with B symptoms?
Approximately 20%.
133
What are the main methods used to confirm a diagnosis of thyroid lymphoma?
* Ultrasound (US)
* Fine needle aspiration cytology (FNAC) using flow cytometry and immunohistochemistry
* Core biopsy
134
What is the standard treatment for diffuse large B-cell lymphoma (DLBCL) in thyroid lymphoma?
3 cycles of R-CHOP plus involved field radiotherapy.
135
In what scenario is radiotherapy alone indicated for MALT lymphoma?
For localized MALT lymphoma.
136
What is the recommended dose of external beam radiotherapy for stage IE MALT type thyroid lymphoma?
24–30 Gy in 12–15 fractions over 2.5–3 weeks.
137
What is the typical treatment approach for patients with bulky disease in DLBCL?
Up to 6 cycles of R-CHOP may be needed.
138
True or False: Thyroidectomy is usually indicated for thyroid lymphoma treatment.
False.
139
What is the recommended administered activity of radioiodine for hyperthyroidism due to Graves' disease?
400–550 MBq of 131 I.
140
What precautions should patients take after receiving radioiodine treatment?
* Avoid close contact with young children or pregnant women for 21–24 days
* Avoid sharing a bed
* Reduce time spent on public transport
* Avoid sharing crockery or cutlery
141
What percentage of patients return to normal thyroid function within 6 weeks after radioiodine treatment?
50–70%.
142
What are the potential long-term effects of anti-thyroid medication?
Irreversible agranulocytosis and hepatic dysfunction.
143
What is the association between Hashimoto's thyroiditis and thyroid lymphoma?
Hashimoto's thyroiditis is associated with thyroid lymphoma in approximately 80% of cases, especially MALT type.
144
What can be difficult to diagnose in thyroid lymphoma?
Occasionally open surgical biopsy is needed if less-invasive methods have failed to establish the lymphoma subtype.
145
What is the significance of IMRT in the treatment of thyroid lymphoma?
IMRT improves thyroid PTV coverage and reduces irradiation of normal tissue compared to conventional techniques.
146
What is a common initial treatment for thyrotoxicosis?
Radioiodine may be given for hyperthyroidism due to Graves' disease or toxic multinodular goitre.
