Oral Presentation NSW State Cancer Conference 2023

Identifying disparities in thyroid cancer staging at presentation across the rural-metropolitan continuum in Australia (#24)

Zihao M Yang 1 2 , Chai Wei Tong 3 , Christine S Lai 4 5 , Christine J O'Neill 6 7 , Nazim Bhimani 1 2 , Anthony Glover 1 2
  1. Sydney Medical School, University of Sydney, Sydney, NSW, Australia
  2. Royal North Shore Hospital, Sydney, NSW, Australia
  3. St George Hospital, Sydney, NSW, Australia
  4. University of Adelaide, Adelaide, SA, Australia
  5. Discipline of Surgery, The Queen Elizabeth Hospital, Adelaide, SA, Australia
  6. John Hunter Hospital, Newcastle, NSW, Australia
  7. University of Newcastle, Newcastle, NSW, Australia

Purpose

Thyroid cancer has seen the largest increases in the incidence of any cancer in Australia over the last several decades. This is thought to be driven by the over-diagnosis of small incidental thyroid cancers, suggesting that increased diagnostic surveillance is a contributing factor. Rural patients have difficulty accessing healthcare practitioners and diagnostic services, and may therefore present with more advanced thyroid cancer. An association between remote residence and advanced tumour staging has been identified in colorectal and kidney cancer in Australia1 2. However, it is unknown whether this association extends to thyroid cancer. In this project, we examined the relationship between thyroid cancer diagnosis by patient location.

Methodology

Data from Australian & New Zealand Thyroid Cancer Registry (ANZTCR) from 2017-2022 was analysed. Patient stratification was performed using postcodes and the Australian Statistical Geographical Classification (ASGC) methodology. The rural group included patients classified into ‘Inner Regional, Outer Regional, Remote, and Very Remote Australia’ areas, and the metropolitan group included patients classified into the ‘Major Cities of Australia’ area. Treatment adequacy and risk category was defined using the American Thyroid Association (ATA) thyroid cancer guidelines.

Results

There were 1,794 patients, with 29.5% residing in a rural location and 70.5% residing in a metropolitan location. Rural patients had lower rates of papillary (79.7% vs 85.1%) and medullary cancer (2.3% vs 2.6%), and higher rates of follicular (16.0% vs 11.4%) and poorly differentiated cancer (1.7% vs 0.4%, p=0.006). The rural group had more cancers larger than 4cm in size (14.2% vs 10.2%, p=0.020). The rural group were more likely to present with advanced overall cancer stage (Stage II-IV, 18.9% vs 14.8%, p=0.037) and advanced T stage (Stage II-IV, 41.6% vs 34.9%, p=0.008). There was no difference in treatment adequacy between rural and metropolitan groups when stratified into low (81.6% vs 80.4%, p=0.667), intermediate (90.9% vs. 87.3%, p=0.517), and high (81.5% vs. 90.6%, p=0.245) ATA risk categories. 

Conclusion

This study shows that rural patients treated by ANZTCR treatment centres are more likely to present with larger tumours at an advanced overall stage. Further studies should investigate the reasons contributing to this disparity and evaluate presentations and outcomes for patients with thyroid cancer who are treated outside of ANZTCR contributing units.

 

  1. Baade, P., Dasgupta, P., Aitken, J., & Turrell, G. (2011). Geographic remoteness and risk of advanced colorectal cancer at diagnosis in Queensland: a multilevel study. British Journal Of Cancer, 105(7), 1039-1041. doi: 10.1038/bjc.2011.356
  2. Satasivam, P., O'Neill, S., Sivarajah, G., Sliwinski, A., Kaiser, C., & Niall, O. et al. (2014). The dilemma of distance: patients with kidney cancer from regional Australia present at a more advanced stage. BJU International, 113, 57-63. doi: 10.1111/bju.12459