What is thyroid cancer?
The statistics provided in this report include patients diagnosed with thyroid cancer. The thyroid is found at the front of the neck and below the voice box. Its function is to make and control hormones which regulate our metabolism - including our heart rate, digestion, body temperature and weight. Thyroid cancer occurs when cells in the thyroid grow and divide in an abnormal way. There are four main types of thyroid cancer. The most common are papillary (70-80%) and follicular (15-20%) cancers; less common are medullary (about 4%) and anaplastic (about 1%) cancers.
How common is thyroid cancer?
In 2019, 739 Victorians were diagnosed with thyroid cancer. Of these, there were 238 males and 501 females, representing 32.2% and 67.8% of the total Victorian thyroid cancer diagnoses, respectively. The median age at diagnosis of thyroid cancer is 55 years in males and 49 in females (Figure 1 & 2). Accounting for 2.1% of all cancers diagnosed and 0.4% of all cancer-related deaths in 2019, thyroid cancer was the 13th most commonly diagnosed cancer and the 29th most common cause of cancer-related deaths in Victoria.
Trends in thyroid cancer over time
Figure 3 shows that since 1982 incidence of thyroid cancer has increased by an average of 6.1% per year in males and increased by an average of 7% in females. Over the past 37 years, mortality from thyroid cancer has increased by 0.2% per year in males and decreased by 1.6% per year in females.
Thyroid cancer morphology
Figure 4 provides a summary of the different types of cells (morphology) which have caused thyroid cancer. Most thyroid tumours, 79.7%, present as Papillary carcinoma tumours.
Geographical variance in thyroid cancer by local government area
Figure 5 demonstrates variation in age-standardised incidence rates of thyroid cancer by local government areas. Darker shading indicates areas with higher rates of thyroid cancer.
Thyroid cancer in people born overseas
Figure 6 shows the age standardised incidence rates of thyroid cancer in Australian-born Victorians compared to other major migrant groups, over the five-year period 2015 to 2019. The highest age standardised incidence rate for thyroid cancer was 6.1 for males born in the Middle East and North Africa region and the lowest rate of 3 was observed in males born in the Africa region. The highest age standardised incidence rate for thyroid cancer was 17 for females born in the Middle East and North Africa region and the lowest rate of 6.1 was observed in females born in the UK and Ireland region.
Thyroid cancer five-year relative survival
Figure 7 demonstrates that five-year relative survival has increased for thyroid cancer between 1989-1993 and 2014-2018 from 86% to 95%.