Diagnostic and epidemiological aspects of thyroid cancers in Côte d›Ivoire
Corresponding author: Dr. N’gattia Koffi Valery, ENT- Head and Neck surgery, teaching hospital of Bouake, Côte d’Ivoire, Email:firstname.lastname@example.org
Cancers of thyroid body are on the whole malignant tumors developed at the expense of the thyroid body. In France, about 8600 new cases of thyroid cancers are diagnosed per year, three-quarters of them are from women . Their incidence in Burkina Faso is 3 cases / year . In Côte d’Ivoire, 57 cases of differentiated thyroid cancers were reported at the Teaching Hospital of Treichville in 18 years .The fine needle biopsy remains the gold standard for the diagnosis of thyroid cancers . This diagnosis also profited from the contribution of ultrasound scan. Indeed, TIRADS (Thyroid Imaging Reporting and Data System) is a quality assurance tool in thyroid scan; It makes it possible, thanks to the nodule evaluation categories, to stratify the individual risk of thyroid carcinoma in order to determine actions to be taken [5-7]. The objective of this work was to describe the diagnostic and epidemiological aspects of thyroid cancers in Côte d’Ivoire.
Materials and MethodThis is a descriptive and retrospective multicentre study carried out in Côte d’Ivoire, in ENT- Head and Neck Surgery Department, Visceral Surgery Department of the Teaching Hospital of Abidjan (Cocody, Treichville, Yopougon), of Bouake, in the Oncology Department of the Teaching Hospital of Treichville and in some private Polyclinics of Abidjan. It was carried out over a period of 15 years (from January 2000 to December 2014).
All the cases of thyroid cancers histologically confirmed of which of patients’ medical records were exploitable, were included.
All the patients with whom the anatomopathological diagnosis of cancer was not made and whose medical records were unusable were excluded.
Data were collected on record forms from hospitalized patients’ medical records and from surgical report books related to patients operated on for thyroid cancer. Paraclinical, clinical, and Epidemiological data were studied.
Prevalence: During the period under review, 85 cases of cancers of the thyroid body were reported over 979 thyroid tumors;
a prevalence of 8.68% with an annual mean incidence of 5.67. Age-corrected incidence are reported in Table I.
Table 1. Age-Corrected Incidence.
Age and sex: 30-60 year-old patients made up 70.59% of the patient population. The average age was 48.76 years old with 14 and 91 year- old extremes. There were 20 male (23.53%) and 65 female (76.47%), a sex ratio of 0.23. Region of origin: The patients were native of the northern, western and central part of Côte d’Ivoire, 28.57%, 28.57% and 17.86% respectively.
Case history: The concept of family goiter was found in 47.62% of the cases. Cervicotomy and partial thyroidectomy were noted in 9 cases (8.57%) and 8 cases (7.62%), respectively. There was neither concept of family cancer nor cervical irradiation.
Chief complaint: The chief complaints are reported in Table II. The anterior cervical swelling accounted for 72.57% of the chief complaints. Signs of constriction (dysphonia, laryngeal dyspnoea, dysphagia) could be found in 24.78% of the cases. The average patient-visit was 7.15 years with extremes of 5 months and 15 years. In 44.05% of the cases, patients consulted within 5 to 10 years.
Table 2. Chief complaints.
Physical findings: The general health was good in 74 cases (87.06%) and affected in 11 cases (12.94%).
Table III summarizes clinical features of thyroid cancers.
Figure 1. Voluminous right thyroid tumor with constriction and deviation of the left larynx.
Indirect mirror laryngoscopy completed by nasofibroscopy done in 56 cases (65.88%) revealed 1 case of hemi larynx (right) which is not very mobile, with a poor closing up of the vocal cords.
The thyroid scan revealed a multi heteronodular thyroid tumor in 62.34% and one nodular tumor in 37.66%. The thyroid hormone assay noted a euthyroidism with all the patients. Cancer positive diagnosis was made preoperatively (aspiration cytology and anatomopathological examination of the adenectomy specimen) in 19% and postoperatively in 81%. Differentiated carcinomas accounted for 88.1% of thyroid cancers (Table IV). Spread assessment: Chest X- ray done for 80 patients (95.24%) revealed pulmonary metastases in 2 cases, i.e. 2.38% (Figure 3).
Table 5. Staging of differentiated tumours.
The diagnosis of differentiated cancers was made on Stage I for 52.7% of the cases. All the 4 undifferentiated carcinomas were on stage IV. Medullary carcinomas (4 cases), myxofibrosarcoma (1 case) and epidermoid carcinoma (1 case) were not staged.
The upward trend of the prevalence of thyroid cancers is observed in the majority of the countries worldwide with, however, rates varying from a country to another . In our study, in Côte d’Ivoire, this prevalence was 8.68%. Our results are close to those reported by Sérémé  in Burkina Faso (8.15%), Sissoko  in Mali (8.8%) and Rahman  in Nigeria (8.2%). For other authors, thyroid cancers represent about 8 to 12% of thyroidectomy cases [2, 8, 9]. This frequency is underrated in our country because some patients do not frequent our hospitals but deliberately refer to the traditional medical practitioners on the one hand and on the other hand due to the fact that many cases of thyroid cancers clinically suspect have not been confirmed.
due to the influence of sex steroids in endocrinopathies including thyroid pathologies .Higher consumption of cassava by the populations of western Côte d’Ivoire which represent 28.57% of the total number of our patients seems to contribute to this disease. Indeed, increased consumption of food such as iodine-rich cassava is one of the risk factors for outbreak of thyroid pathologies . The concept of family goiter, which is a risk factor for outbreak of thyroid cancers [10-11] accounted for 47.62% of the cases.Paraclinical and clinical aspects
The anterior cervical swelling was the chief complaint in our study (72.57% of the cases). This finding was made by Sérémé  and Sissoko  with respectively 84.21% and 46.2%. The unsightly character of this anterior cervical swelling could explain this. Signs of constriction (dysphonia, laryngeal dyspnoea, dysphagia) motivated patient-visit for 24.78% in our series against 75.4% for Sissoko’s . This difference seems to be related to the stages in which the patients consult.
The average patient-visit period was 7.15 years with a high rate of 44.05% between 5 and 10 years in our series. This delay is less than Adama’s  who found an average duration of 10.1 years. The consultation period is long in both cases. The thyroid pathology due to its high frequency in our regions is considered benign and therefore does not worry the population. Moreover, thyroid swelling is considered as a beauty feature in some customs of western Cote- d’Ivoire. The decision to consult is often made only if complications arise with signs of constriction or extension of the tumor to the skin.
Physical examination estimates the characteristics of the tumor but also the presence or absence of cervical adenopathy. Thyroid nodules are very common and less than 10% of them are malignant . For Bombil , the risk of malignancy of multiheteronodular goiters is about 7.5%. In the present study, tumors were developed at the expense of one lobe in 69.04% and two lobes in 29.76% of the cases. However, in Adama’s , they were bi-lobar in 50% of the cases. The stage of development could have an impact on the clinical presentation of the tumor. Indeed, it is possible to admit that the tumors that develop for several years (10-15 years) can become multi heteronodular and voluminous or even bi-lobar compared to those that have recently evolved. Besides, these tumors were firm (83.33%), painless (85.71%), mobile (88.10%) with a healthy covering skin (91.67%). This contrasts with the criteria of malignancy of thyroid cancers reported in the literature  and which seems to attest the clinical polymorphism of these cancers.
The examination of the larynx in search of paralysis or recurrent paresis has a medico-legal and diagnostic interest. It seeks for a laryngeal extension of the thyroid cancer. It is therefore important to maintain a better collaboration between visceral surgical department and ENT specialists for a laryngeal examination systematically for any patient who has a thyroid tumor.
Euthyroidism was observed for 95.9% and hyperthyroidism for 4.1% in Sissoko’s series . In Sérémé’s study  as well as in ours, all the patients were in euthyroidism. This is due to the fact that before any thyroid surgery, patients’ preparation aims at obtaining euthyroidism by prescribing synthetic antithyroid drugs in case of hyperthyroidism and levothyroxine, in case of hypothyroidism .
The prescribed cervical scan was done for 77 patients with 62.43% of many nodules found. This high frequency of this examination could be explained by the accessibility to scan in our hospitals and its low cost. Predictive Ultrasonic factors of malignancy of nodular goiter are hypoechoic character, hazy limits, presence of microcalcifications and visualization of an intranodular vascularization with or without perinodular vascularization . The TIRADS score, a simple and practical method of assessment of thyroid nodules, has a high positive predictive value of malignancy in the literature [5,7]. For Njock, the scan coupled together with TIRADS classification has a diagnostic value that is statistically significant to predict malignancy or benignity during final histological examination, thus allowing this method to be used in the prioritization of the risk of thyroid carcinoma in African environment . This score was not used in our series.
Preoperatively, the diagnosis of thyroid cancer was made for 13 cases of which 3 cases after fine needle aspiration cytology. Aspiration cytologies are poorly carried out due to the relatively recent experience of cytologists as regard thyroid aspiration cytologies . Fine needle aspiration cytology is a standard examination in diagnosis of thyroid cancer; however the risk of false negative with patients with multi-heteronodular goiter is 5.7% . The anatomopathological diagnosis of the surgical specimen is essential, but there are false negatives and false positives. The predominance of differentiated cancers in our series (88.1%) confirms the data of the literature [2,10,11,12].
Thyroid cancers are lymphophilic and the rate of metastasis varied according to studies. We found 21.43% of metastases predominantly lymph- node (72.22%) and pulmonary (16.67%). Our rate is lower than Rebaï’s  which is 37% but distinctly higher than that of other authors who reported 11.1% , 5%  and 1.3%  of Metastases. The diagnosis of differentiated cancers was made in stages I and II for respectively 52.70% and 28.38% of the cases.
The prevalence of thyroid cancers was 8.58% in our study. Differentiated cancers were predominant. The standard practice of aspiration cytology combined with the application of TIRADS score will permit to improve the diagnosis and prognosis of thyroid cancers in Côte d’Ivoire.
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