Oral Presentation Clinical Oncology Society of Australia Annual Scientific Meeting 2022

Targeted thromboprophylaxis in ambulatory patients receiving anticancer therapies for lung or gastrointestinal cancers (TARGET-TP): a randomized networked teletrial (#72)

Marliese Alexander 1 2 , Craig Underhill 3 4 , Ben Solomon 2 5 , David Ball 2 5 , Michael MacManus 2 5 , Samuel Harris 6 , Javier Torres 7 , Nora Lee 2 , Alexander Heriot 2 5 , Jeanne Tie 2 , Sharad Sharma 3 , RIchard Eek 3 , Rory Wolfe 1 8 , Kate Burbury 2 5
  1. Monash University , melbourne, Victoria, Australia
  2. Peter MacCallum Cancer Centre, Melbourne, VIC, Australia
  3. Border Medical Oncology, Albury Wodonga Regional Cancer Centre, Albury Wodonga, VIC, Australia
  4. Rural Medical School, University of New South Wales, Albury Campus, NSW, Australia
  5. Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia
  6. Bendigo Health, Bendigo, Victoria
  7. Medical Oncology, Goulburn Valley Hospital, Shepparaton, VIC, Australia
  8. Department of Epidemiology and Preventive Medicine, Monash University , Melbourne, Victoria, Australia

BACKGROUND: Cancer-associated thromboembolism is common and consequential. Benefits of targeted-thromboprophylaxis for ambulatory patients receiving systemic therapy are proven, however uptake remains limited. An improved risk-directed strategy, capable of real-time application is needed.     

METHODS: Open-label PIII randomized trial among patients with lung or gastrointestinal cancer planned to receive systemic anticancer therapy. Conducted as a networked-teletrial to enhance regional/rural recruitment. A risk score stratified thromboembolic risk according to fibrinogen and d-dimer levels: low-risk (observation, no intervention) and high-risk (1:1 randomization to enoxaparin 40mg daily or no therapy). The primary outcome was confirmed thromboembolism at 180 days. Key secondary outcomes included bleeding, risk model performance, and survival parameters. Also compared potency and pragmatic application of published risk models, to guide routine clinical utilisation.

RESULTS: Of 328 patients, 200 (61%) were high-risk and randomised; 128 (39%) low-risk. 152/328 patients were recruited at regional-networked sites. Among high-risk, thromboembolism rates randomized to enoxaparin were 8/100 (8%) and 23/100 (23%) untreated: HR 0.31, 95% CI 0.15 to 0.70, P=0.005. Low-risk thromboembolism rate was 10/128 (8%): untreated high-risk v low-risk HR 3.33, 95%CI 1.58 to 6.99, P=0.002. Similar rates were observed for randomized high-risk enoxaparin and low-risk observational cohort. Major bleeding was uncommon: 1% enoxaparin, 2% untreated high-risk, 2% low-risk, P=0.88. Application of published risk scores to trial cohort - sensitivity and specificity (respectively): TARGET-TP 70%/61%, KS 39%/68%, PROTECHT 70%/37%, CONKO 39%/69%, CATS/MICA 27%/87%. Notable cohort migration with 75% “TARGET-TP high risk” (TE rate 23%) designated low-risk by other models and "ineligible" for targeted-thromboprophylaxis.

CONCLUSIONS: TARGET-TP risk-model discriminated high (23%) and low (8%) thromboembolic risk. Application of targeted-thromboprophylaxis mitigated the risk substantially to a level comparable with low-risk, without safety concerns. Low-risk patients avoided unnecessary intervention. The decision-making algorithm is simple, pragmatic, can be applied real-time in clinic, with routine care pathways and should become standard of care.