Follicular Thyroid Carcinoma in a Country of Endemic Iodine Deficiency (1994-2013)

Clinicopathological profile and management of thyroid carcinoma: a Sub-Saharan country experience

BACKGROUND

In Sudan, there is limited knowledge on the epidemiology, clinical characteristics and pathological patterns of thyroid cancer. To address this shortcoming, we studied the clinical, pathological and treatment patterns of thyroid cancer at the National Cancer Institute ‒ University of Gezira (NCI-UG), Sudan.

METHODS

We performed a retrospective health facility-based study of patients with thyroid cancer who were treated at NCI-UG from January 2009 to December 2017.

RESULTS

A total of 139 patients with thyroid cancer were identified during the study period. Tumors were more common among women (69%). Goiter was the main presenting symptom (85%). The most common type of thyroid cancer was follicular carcinoma (41%), followed by papillary carcinoma (24%), then anaplastic carcinoma (20%). The mean age of the women was 56.3 years (SD ± 14.7), compared to 52.5 years (SD ± 16.6) for the men. The frequencies of stage I, II, III, and IV were 17%, 22%, 16%, and 45%, respectively. Different types of thyroidectomies were performed in 79% of the cases, lobectomy in 4%, and no surgery in 17%. Only 28% of the cases received radioactive iodine. Palliative chemotherapy and radiotherapy were prescribed to 17% and 37% of the cases, respectively.

CONCLUSION

Thyroid cancer is more prevalent among women and most patients present at later stages. The dominance of follicular type suggests that the majority of this population is iodine-deficient.

Thyroid cancer incidence and trends by demographic and tumor characteristics in Oran, Algeria: 1993-2013, a population-based analysis

OBJECTIVES

Incidence rates of thyroid cancer have dramatically increased over recent decades in many countries, particularly the papillary histotype and microcarcinomas. We examined thyroid cancer incidence and trends by demographic and tumor characteristics based on 1443 patients with thyroid cancer diagnosed between 1993 and 2013 in Oran district, in Northwest Algeria.

METHODS

All thyroid cancer cases were abstracted from medical records and pathology reports and classified according to the International Classification for Diseases in Oncology, third edition. Age-specific, age-standardized incidence rates per 100 000 person-years, and annual percent changes (APC) in the incidence were calculated.

RESULTS

Age-standardized incidence was 11.7 per 100 000 for women and 2.0 per 100 000 for men. Thyroid cancer incidence increased over time significantly in women (APC: +3.72%; P < 0.05), mostly due to an increased incidence of the papillary histotype (APC: +5.48%; P < 0.05), and microcarcinomas (APC: +17.34%; P < 0.05). During the same time period, the incidence of follicular thyroid carcinomas decreased (APC: -3.74%; P < 0.05).

CONCLUSIONS

The results of our study showing an upward trend of thyroid cancer incidence driven largely by increases in the papillary histotype are consistent with previous studies. The higher increase has coincided with the introduction of fine needle aspiration and thyroid ultrasound in the 1990s, and may have led to overdiagnosis. However, the increased papillary-to-follicular ratio observed over time is possibly a late effect of iodine supplementation implemented in Algeria in 1967 to combat endemic goiter. Further larger-scale population-based research is needed to gain insight into thyroid cancer etiology.

Changes in the Demographic and Clinicopathological Characteristics of Thyroid Cancer: A Population-Based Investigation in Algeria, 1993-2013

Over the last three decades, the incidence of thyroid cancer has increased worldwide. The reasons for this increase remain controversial. In Algeria, however, to date, information on thyroid cancer has been limited to a hospital-based case series. We analyzed data from a population-based cohort study in Oran District, Algeria, to describe demographic and clinicopathological characteristics of patients diagnosed with thyroid cancer between 1993 and 2013. Medical records and pathology reports of thyroid cancer patients who had surgery were reviewed. Changes in demographic and clinicopathological features over the 21-year period are described. During the study period, thyroid cancer was diagnosed in 1248 women (86.5%, mean age 43.7 ± 15.2 years) and 195 men (23.4%, mean age 48.1 ± 15.9 years). Most cases (83.1% for women and 69.8% for men) sought a diagnosis following a self-neck check. The most common histologic types were papillary (58.3%), follicular (29.7%), anaplastic (4.1%), and medullary (0.8%) carcinomas. The incidence of papillary carcinomas significantly increased (p < 0.001) while the incidence of other histologic types significantly decreased over time. Tumor size overall significantly decreased (p < 0.001) while the frequency of small (≤20 mm) and larger (>20 mm) carcinomas significantly increased (p < 0.05). The frequency of thyroid cancers with capsular effractions and angioinvasions also decreased over time. Thyroid cancer incidence in Algeria has increased substantially in line with international trends with changes in clinical practice being a possible contributing factor. However, the increasing papillary-to-follicular cancer ratio may be due to changes in iodine nutrition status in Algeria. Further research, including exploration of biological and molecular features of thyroid cancer, will enable a better understanding of risk factors and etiopathogenetic mechanisms.