Thyroid cancer in the Democratic Republic of the Congo: Frequency and risk factors

The prevalence of thyroid cancer is increasing steadily in most countries, partly due to better, earlier diagnosis. However, there is little data for developing countries, where the technical platform is often very limited, especially in Africa.

To assess the frequency of thyroid cancer in the Democratic Republic of the Congo (DRC) and to analyze the epidemiological, clinical, and ultrasound risk factors.

This is a multicenter cross-sectional study of 594 patients operated on for a thyroid mass from 2005 to 2019, in 35 centers in the DRC and for whom histopathological analyses were performed.

The frequency of thyroid cancers in our cohort was 20%, mostly in patients over the age of 40 (62% of patients). These cancers were mainly diagnosed at the clinical stage, due to the presence of palpable masses. Papillary cancer was the most common (67.2% of patients), followed by follicular cancer (28% of cases). We found a high prevalence of anaplastic cancer (7.6%). These frequencies are probably the consequence of the fact that histopathological analyses are not systematically performed in the DRC, but mostly on tissues that the thyroid surgeons suspect to be malignant. Age ≥60 years, the presence of adenopathies upon palpation or on ultrasound, the solid nature and hypoechogenicity of nodules, the presence of macronodules and calcifications were the factors independently associated with the diagnosis of cancer in the study population.

In this first study performed in the DRC, we have found that thyroid cancer is common. It is mainly detected at clinical stages, with patients over the age of 40 years and women being the most affected. The histopathology distribution differs from that in developed countries, with a lower prevalence of papillary cancer and a higher prevalence of the anaplastic type. In developing countries, it appears necessary to introduce the use of more precise diagnostic tools for thyroid cancer and also, to reinforce the improvement of known, controllable risk factors such as iodine deficiency.