Introduction

Thyroid cancer is the most common malignancy diagnosed in the endocrine system and accounts for between 5% and 10% of thyroid nodules biopsied in endocrine services. The incidence of thyroid cancer has increased over recent times due to the increased use of computed tomography (CT) and magnetic resonance imaging (MRI) scans in the management of other medical conditions and cancer staging.

A study examining cancer incidence among the Bahraini population between 1998 and 2002 reported thyroid cancer as one of the most common malignancies among females, with Bahraini women demonstrating higher incidence rates compared to other Gulf Cooperation Council (GCC) countries. Approximately 95% of malignant thyroid cancers arise from follicular cells and are classified as papillary, follicular, or anaplastic carcinomas. Papillary thyroid carcinoma accounts for approximately 80% of cases. Risk factors include obesity and radiation exposure.

This study aims to recognise the incidence of thyroid cancer in Bahrain from 2019 to 2021 and to describe the demographics, modes of presentation, histological subtypes, and treatment options among affected patients.

Materials and Methods

This was a retrospective, observational, cross-sectional study. Access to the electronic files of all patients diagnosed with thyroid cancer and discussed at the National Tumour Board between 2019 and 2021 was granted by the Bahrain Oncology Centre. A total of 183 patients were initially identified; however, four were found to have benign aetiologies on biopsy and were excluded. The final study population comprised 179 patients.

Data were extracted into a structured Excel spreadsheet and included patient demographics, risk factors, age at diagnosis, clinical presentation, tumour characteristics, stage at diagnosis, presence of metastasis, thyroid-stimulating hormone levels prior to diagnosis, thyroglobulin levels after surgery and at one year, genetic mutations where available, and treatments performed. As this study was based on a retrospective anonymised dataset, informed consent was waived. Descriptive analysis was performed using IBM SPSS Statistics software.

Results

Between 2019 and 2021, 179 patients diagnosed with thyroid cancer were discussed at the National Tumour Board in Bahrain, corresponding to an estimated average annual incidence rate of 4.01 new cases per 100,000 person-years. The majority of patients were female and Bahraini. Most patients were aged between 35 and 64 years. Although weight and height data were unavailable for many patients, among those with recorded measurements, most had a body mass index between 25 and 29.9.

Most patients presented with asymptomatic neck swelling. A substantial proportion were incidentally diagnosed during screening for other diseases or thyroid conditions. Some patients presented with neck swelling accompanied by symptoms such as neck fullness, pain, dysphagia, or unintentional weight loss, while a smaller group was symptomatic without neck swelling.

Papillary thyroid carcinoma was the most common histological subtype identified. Most cases were of an unspecified papillary variant. Tumour staging was predominantly performed using the AJCC TNM Staging 8th Edition, with most patients presenting with small tumours. In some cases, nodal involvement or metastasis could not be evaluated, and a minority of patients were not staged due to lack of surgical intervention.

The majority of patients did not have distant metastasis. When present, metastases involved sites such as bone, lung, pharynx, pleura, and brain. Most patients underwent total thyroidectomy, often combined with nodal dissection and radiotherapy. A small number of patients did not receive any intervention.

Discussion

The incidence of thyroid cancer has increased globally, largely due to enhanced detection from advanced imaging modalities. Data from the Middle East remain limited, particularly from Bahrain. The incidence rate observed in this study falls below high-incidence regions but is comparable to rates reported in neighbouring countries. A strong female predominance was observed, consistent with global trends, potentially linked to hormonal mechanisms involving oestrogen-mediated thyroid cell proliferation.

Papillary thyroid carcinoma accounted for the majority of cases, aligning with global histological distributions. Obesity has been identified as a potential risk factor for thyroid cancer, and although many patients in this study were overweight or obese, the retrospective design and timing of BMI measurement limit causal interpretation.

Most patients underwent total thyroidectomy, reflecting current clinical practices. While hemithyroidectomy has been advocated for selected low-risk cases to reduce postoperative complications, total thyroidectomy remains indicated for larger, invasive, or metastatic tumours. The findings suggest the need for early detection strategies, targeted public health awareness—particularly among women aged 35–64 years—and adherence to risk-stratified surgical guidelines.

Conclusion

Between 2019 and 2021, thyroid cancer in Bahrain had an estimated average annual incidence rate of 4.01 new cases per 100,000 person-years. The disease was more prevalent among Bahraini females, most commonly presenting in the 35–64-year age group. Papillary thyroid carcinoma was the predominant histological subtype, and most patients were treated with total thyroidectomy with nodal dissection and radiotherapy. These findings underscore the importance of strengthening early detection strategies, improving public awareness, and optimising surgical decision-making to balance oncologic outcomes with postoperative morbidity.