Poster Presentation 2025 Joint Meeting of the COSA ASM and IPOS Congress

Current practice of medical oncologists in cancer of unknown primary: results from a national survey (126694)

Tiffany Foo 1 , Ganessan Kichenadasse 1 2 , Claire Vajdic 3 , Abigail Miller 1 , Richard Tothill 4 , Nadia Corsini 5 , Alex Brown 6 , Anna Brown 7 , Daniel Thomas 8 , Hamish Scott 8 , Justine Clark 9 , Greg Pratt 10 , Sean Grimmond 4 , Alison Richards 1 , Ifrah Hasan 1 , Rebecca Cato 1 , Zarina Greenberg 1 , Chris Karapetis 1 2
  1. Flinders Centre for Innovation in Cancer, Bedford Park, SA, Australia
  2. Flinders University, Bedford Park , SA
  3. Kirby Institute, University of New South Wales, Sydney, NSW, Australia
  4. University of Melbourne, Parkville , VIC, Australia
  5. University of South Australia, Adelaide, SA, Australia
  6. National Centre for Indigenous Genomics, Australian National University, Canberra, ACT, Australia
  7. SA Pathology, Adelaide, SA, Australia
  8. The University of Adelaide, Adelaide, SA, Australia
  9. The Kids Research Institute Australia , Perth, WA, Australia
  10. Office of Indigenous Engagement, CQUniversity, Brisbane, Qld, Australia

Background

Cancer of Unknown Primary (CUP) is a metastatic cancer with no identified primary site. It is a diagnosis of exclusion after comprehensive evaluation.

In Australia, CUP constitutes 1.6% of all cancers, with incidence falling from 16 to 7.4 per 100,000 persons between 1982 and 2022. The 5-year survival rate remains low at 13%. The Optimal Care Pathway (OCP) was published in 2020 to improve care.


Methods

As part of a project to improve CUP patient outcomes, an online survey was distributed to all the Medical Oncology Group of Australia (MOGA) physician members to assess CUP diagnostic and treatment practices.

The nine-question survey included respondent demographics, assessed their familiarity with the CUP OCP, and focused on the common diagnostic investigations for CUP.


Results

The study was conducted from February 1, 2024, to October 31, 2024, with a total of 63 respondents. The majority (77.4%) practise in both private and public urban hospitals. 82.5% of respondents routinely request serum tumour markers. Nearly all (96.8%) request CT scans as part of routine investigations; PET scans were less frequent (54.1%). In terms of molecular testing to identify the primary site of origin and guide targeted therapies, 34.9% of respondents always request a molecular test while 36.5% do so 50-90% of the time. Six respondents do not use molecular tests at all. Additionally, only 23.8% of respondents are familiar with the CUP OCP.


Conclusions

Molecular testing is crucial for guiding targeted therapies and identifying tumour origin. Although molecular testing is still relatively new, approximately 70% of respondents will utilise molecular testing at least 50% of the time. Only half of respondents utilize PET scan, potentially reflecting resource limitation. Lastly, awareness of the CUP OCP is low, indicating a need for further education.