Summary
Diagnosis
- Thyroid cancer is a rare condition. Thyroid nodules is a common phenomenon.
- Cancer is suspected when a hard, fast-growing process in the gland with recurrent paresis is observed.
- The general recommendation upon observation of thyroid nodules, is to perform thyroid scintigraphy using ultrasound and biopsy of inactive solid tissue in the thyroid gland.
- Diagnosis is confirmed by histology.
Treatment
- Surgery: Hemithyroidectomy or total thyroidectomy depending on the size and histology of the cancer.
- Treatment with med radioactive iodine in case of total thyroidectomy.
- Chemotherapy/radiation therapy is rarely used.
Referral - When suspecting thyroid cancer, the patient is referred to a package process at an ENT department.
- When observing nodules in the thyroid gland, these should be referred to an ordinary examination using scintigraphy and ultrasound, if necessary a biopsy.
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Diagnosis
Diagnostic criteria
- Histology after surgical removal results in a final diagnosis: thyroid cancer. The following types exist:
- Differentiated thyroid carcinomas have developed from the follicular epithelium. These constitute approximately 85% of all cases of thyroid cancer. These are eitherpapillary or follicular carcinomas.
- Medullary carcinomas are neuroendocrine.
- Undifferentiated (anaplastic) carcinomas.
- Others (typically metastases or lymphomas)
Medical history
- Differentiated carcinomas
- Often present with a painless nodule in the thyroid gland
- Medullary carcinomas
- May cause diarrhoea, fatigue and other symptoms caused by the production of serotonin and prostaglandin and hormonally active peptides 1
- Anaplastic carcinomas
Clinical findings
- Solid, painless tumour
- Local lymph nodes may be enlarged
Additional examinations in general practice
- Usually normal TSH, T4 and T3
Other examinations by a specialist or at a hospital
At a specialist hospital clinic
- If suspicion of cancer is conformed, the primary choice is ultrasound with a biopsy
- In case of minor suspicion, scintigraphy is primarily preferred, and if this shows an active process/a "warm" adenoma, the suspicion of cancer is reduced
- Fine needle aspiration with a cytologic assessment 2, 3
- Can be performed using ultrasound guidance
- Papillary, medullary and anaplastic carcinomas are easily diagnosed based on cytology
- Follicular carcinomas and benign follicular adenomas cannot be separated using cytology. For cytologic, follicular neoplasm, surgical intervention should be performed (carcinomas can be distinguished from adenomas by way of penetration through the capsule/contiguity – vessel ingrowth
- Scintigraphy
- To determine whether there is an inactive process/"cold" nodule
- CT scan
- Is relevant first to detect metastases and for stage stratification
- Laboratory analyses
- Differentiated carcinoma
- Medullary carcinoma
- It may be relevant to quantify S-calcitonin and S-calcium; catecholamines are measured either in blood or urine
Differential diagnoses
Treatment
2
Aim of treatment
- Complete tumour resection
Generally about the treatment 2
Differentiated carcinomas
- A multimodular regime
- Surgery
- Total thyroidectomy is preferred in differentiated carcinomas. If the tumour is smaller than 2 cm, hemithyroidectomy can sometimes be sufficient
- Post-operative radioactive iodine therapy
- In rare cases, chemotherapy or external radiation therapy
Other carcinomas
- Medullary carcinomas
- Surgery
- In rare cases, external radiation therapy
- Anaplastic carcinomas
- Operation if possible
- Sometimes palliative external radiation therapyChemotherapy is less effective
Surgery
- Differentiated carcinomas
- Total thyroidectomy, for tumours smaller than 2 cm hemithyroidectomy can sometimes be sufficient
- Removal of lymph nodes
- The intervention implies a risk of hypoparathyroidism and injury to the recurrent nerve
- Surgery may be relevant to remove solitary metastases
- Medullary carcinomas
- Total thyroidectomy
- Removal of lymph nodes
- If medullary thyroid cancer is cytologically or histologically verified, a pre-operative analysis for catecholamines should be performed on a 24-hour urine sample because of the risk of pheochromocytoma. Examination of mutation of the RET proto-oncogene may take place after the final histological diagnosis of medullary thyroid carcinoma
Radioactive iodine
- Post-operative treatment with I-131 in all patients with a high risk of relapse following surgery
- Differentiated carcinomas (papillary and follicular)
- Is administered after initial surgery as an adjuvant therapy following a total thyroidectomy – increases survival and quality of life by:
- destroying remaining foci of the disease
- increasing the specificity of the thyroid scintigraphy when looking for recurrent or metastatic disease
- improving the S-thyroglobulin measure – a serum marker which is secreted by thyroid cells
- In case of recurrent and distant metastases, radioactive iodine therapy is recommended after optimal surgery
- To ensure maximum uptake of radioactive iodine, the thyroid hormone concentration should be so low that TSH will increase to 25-30 mU/l
- Medullary carcinomas
- Radioactive iodine therapy has no effect
Chemotherapy
- Is rarely used to treat disseminated papillary and follicular thyroid cancer
External radiation therapy
Medical treatment
Substitution treatment
- Lifelong substitution treatment with levothyroxine and possibly calcium and vitamin D against hypoparathyroidism after surgery
- Levothyroxineis administered is slightly elevated doses to completely or partially suppress TSH, depending on the risk of relapse in order to avoid stimulation of tumour growth. If the condition is stable without any signs of relapse after two years, the levothyroxine dose is often slightly reduced to keep TSH low within the normal range
Palliative treatment
- The most common thyroid cancers are highly differentiated cancers with benign progress and palliative treatment is rarely needed.
Prophylatic treatment
- Prophylactic thyroidectomy is recommended for family members who carry a mutation of medullary thyroid cancer 4
- Prophylactic surgery of 5-6-year-olds for MEN 2A and isolated familial medullary thyroid cancer is recommended, and of 6-12-month-olds for MEN 2B 4
Referral
- Immediately if the diagnosis is suspected
- For goitre /thyroid nodule – random findings, without a verified suspicion of cancer (fast growth, recurrent paresis, solid tissue) – the patient is referred primarily to an endocrinologist for evaluation of metabolism, potential radioactive iodine therapy, evacuation of cyst content etc. 3
- In case of verified suspicion of thyroid cancer, the patient is introduced to a cancer package process
Follow-up
2
Plan
- Normally, follow-up is managed by a hospital clinic for 2-5 years – some patients longer because of persistent disease
- The purpose of the hospital follow-up procedure is:
- To trace potentially curable relapses:
- by palpation/ultrasound/scintigraphy,
- by thyroglobulin measurement as a tumour marker of follicular and papillary thyroid cancer and by calcitonin measurement as a tumour marker in medullary thyroid cancer
- To treat treatment-related morbidity
- To ensure that the patient's metabolism is adequately regulated (TSH level 0.1-0.5 mU/l)
- To treat potential calcium issues
- Upon final discharge from the hospital, the patient is considered cured
Management in general practice
- Is followed up by annual control of TSH
Course of diseases, complications and prognosis
Course of diseases
- Papillary carcinomas rarely metastasize.
- Follicular carcinomas often result in distant metastases which, however, often diminish during radioactive iodine therapy
- Medullary metastases locally and generally
- At the time of diagnosis 50 % have metastasized
- The mortality of anaplastic carcinomas is close to 100 %
- Usually present widely local ingrowth and high occurrence of distant metastases in lungs, pleura, bones and brain
Complications
- Risk of thyrotoxic complications
- TSH suppression caused by thyroxine treatment can accelerate osteoporosis 2, trigger atrial fibrillation 5and cause cardiac hypertrophy, cardiac dysfunction and reduced quality of life 6
- Metastases may occur after a long time (10-20 years)
Prognosis
7
- The most important prognostic factor is the histological type
- Papillary carcinomas: The tumour-specific survival rate after five years is approximately 95 % and after 10 and 20 years approximately 90 %
- Prognostic factors are tumour size, tumour dissemination (stage) and age (best prognosis in younger patients (< 40-50 years))
- Follicular carcinomas: The tumour-specific survival rate after five years is approximately 90 % and after 10 years approximately 85 %
- Prognostic factors as for papillary carcinomas
- Medullary carcinomas: The tumour-specific survival rate after five years is approximately 80% and after 10 years approximately 60%
- Prognostic factors are tumour size and tumour dissemination (stage), age (better prognosis in younger patients); the prognosis is slightly worse in patients with MEN 2B
- Anaplastic carcinomas: According to most literature, the median survival is approximately four months. Almost all patients have died within 12 months following diagnosis. All patients are classified as stage IV. A few patients with a small focus of anaplastic carcinoma in an otherwise differentiated thyroid cancer can become long-time survivors
Background information
8, 9
Definition
- Differentiated thyroid carcinomas have grown from the follicular epithelium and constitute approximately 85% of all thyroid cancers
- Are either papillary carcinomas or follicular carcinomas
- Medullary carcinomas are neuroendocrine
- Thyroid cancer is divided into stages according the TNM system
- T – distribution of tumour
- N – lymph node involvement
- M – occasionally distant metastases
Classification
- Papillary carcinomas
- Follicular carcinomas
- Medullary carcinomas
- Undifferentiated (anaplastic) carcinomas
- Others
Occurrences
8, 9
- In 2016, a total of 320 patients were diagnosed with thyroid cancer in Denmark. Increasing incidence has been observed in several countries worldwide, and a recent study from the Danish Thyroid Cancer Group (DATHYRCA) has shown that this is also applies to Denmark. 10
- The reason is primarily the small (defined as microcarcinomas < 1 cm) papillary carcinomas which are now diagnosed more frequently than previously, in part because of increasing use of imaging technologies and better pathologic methods. The importance of small papillary carcinomas remains not known.
- Like other diseases in this organ, thyroid cancer is most frequently found in women, at a ratio of 3:1.
- The median age at the time of diagnosis is 45 years for differentiated carcinomas.
Occurrence of the different types
- Papillary carcinomas
- Are the most frequently found carcinomas in the thyroid gland: approximately 70 %
- Follicular carcinomas
- Constitute approximately 15 % of all thyroid cancers
- Medullary carcinomas
- Have grown from C cells, constitute approximately 7 % of thyroid cancers
- Undifferentiated (anaplastic) carcinomas
- Constitute approximately 8 % and occur almost exclusively in elderly patients
Predisposing factors
- Previous radiation exposure of neck and head, among others after treatment of child cancer 11
- Familial medullary carcinoma4
- A mutation of the RET proto-oncogene can be shown
- Mutations are an autosomal dominant inheritance and a cause of cancer with almost 100% penetrance
- Screening is recommended from early childhood if there is a genetic predisposition
ICPC-2
ICD-10/SKS codes
Patient information
Links for patient information
Palliative treatment of progressive cancer
Patient organisations
Links for guides
- National treatment guides from medical societies
- Descriptions of processes and package processes
Illustrations
