Poster Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2023

Real-world REarranged during Transfection [RET]-alteration testing andtreatment patterns of patients with medullary and papillary thyroid cancer [MTC, PTC] in Australia. (#307)

Grace Segall 1 , Urpo Kiiskinen 1 , Angela Lai 2 , Kristine Mapstone 2 , Isaac Sanderson 3 , Katie Lewis 3 , Alex Rider 3
  1. Eli Lilly and Company , Indianapolis, USA
  2. Eli Lilly Australia Pty Ltd, Sydney, NSW, Australia
  3. Adelphi Real World, Bollington, Macclesfield, UK

Aims: RET-mutations occur in ~60% of MTC and RET-fusions in ~10-20% of PTC patients1,2. Given limited research into MTC and PTC in Australia, this study describes RET-alteration testing and treatment patterns for these patients in Australia.

Methods: Data were drawn from the Adelphi Real World Thyroid Cancer Disease Specific Programme™, a cross-sectional retrospective survey of physicians and their patients, conducted between September 2021 – February 2022. Medical records were descriptively analysed for physicians’ next five presenting advanced thyroid cancer patients.

Results: Data from 22 of 30 targeted Australian physicians were collected. Physicians abstracted medical records for 28 MTC and 81 PTC patients. 50 (45-65) and 50 (38-65) years for MTC and PTC, respectively.

89% (n=25) of MTC and 5% (n=4) of PTC patients were tested for RET mutation and RET fusion respectively. Of RET mutation-tested MTC patients, 68% were tested using Next-Generation Sequencing (NGS), 28% using Polymerase Chain Reaction; the rest were unknown. 52% of tested MTC patients were RET-mutation-positive. Three RET fusion-tested PTC patients were tested with FISH, one with NGS. All RET fusion-tested PTC patients were RET-fusion negative.

First line (1L) advanced systemic treatment was commonly managed by medical oncologists for MTC (72%) and endocrinologists or medical oncologists (36%, 34%) for PTC patients.  75% of MTC and 83% of PTC patients underwent surgery for advanced disease. At the time of data collection, 36% of MTC and 28% of PTC patients had received or were receiving 1L drug treatment; 40% of MTC patients received cabozantinib and 78% of PTC patients received lenvatinib.

Conclusion: Although most MTC patients were tested for RET mutation, PTC patients were rarely tested for RET fusion. As RET-targeted therapies could soon become available in Australia, testing must occur to identify patients who are likely to clinically benefit from them.