Pathways to the diagnosis of thyroid cancer in New South Wales: a population-based cross-sectional study

Over the past few decades, an increase in the incidence of thyroid cancer has been recorded in many countries around the world including Australia. Heightened medical surveillance and increased technological sensitivity could be contributing to greater detection of asymptomatic disease. To describe the pathways to diagnosis of thyroid cancer for a cohort of newly diagnosed patients in New South Wales (NSW), Australia, and compare these pathways by age, sex, place of residence, ethnic background, medical insurance status, and disease characteristics. A total of 452 newly diagnosed cases of thyroid cancer were recruited through the population-based NSW Central Cancer Registry. Participants completed a questionnaire and diary of doctor visits and investigations that led to their diagnosis. Tumor characteristics were obtained from pathology reports. Forty percent of patients initially presented to their doctor with a lump or symptom specific to thyroid cancer and 60% had their cancer detected incidentally during a medical encounter. Men were more likely than women to be diagnosed after imaging for another health concern versus reporting a thyroid lump or symptom (p = 0.001). Thyroid cancer diagnosis after imaging for another health concern increased with age (p = 0.023), and larger tumors were less likely to be diagnosed after treatment for a benign thyroid disease (p = 0.040). As the majority of participants had incidental diagnoses, the reported incidence of thyroid cancer is likely to be influenced by diagnostic technology and medical surveillance practices. This, however, probably only partly explains the observed rise in the incidence of thyroid cancer in NSW.