Abstract

Can Precision Medicine be Used in Treating Head and Neck Cancer Patients?

Chamindie Punyadeera, Associate Professor/Head/Saliva Translational Research Group, Queensland University of Technology

Metastasis in head and neck cancer (HNC) patients is reflected by measurable levels of circulating tumour cells (CTCs) in the peripheral blood of these patients. CTCs represent cancer cells from the primary and metastatic sites, thereby providing a comprehensive representation of the tumour burden of an individual patient. For patients without CTCs at presentation, the detection of CTCs in the blood and analysis of biomarkers within them, provide an opportunity to identify patients ‘at-risk’ of developing overt metastasis, accelerating targeted treatment in addition to tailoring routing care with an aim of improving cure.
Our study aimed to assess whether CTCs isolated from bloods collected from HNC patients (n=150) could provide early evidence of distant metastases. With significant advances in CTC isolation technologies, we could demonstrate a higher CTC capture efficiency (70% vs 25%) using epitope-independent platforms. By assessment of single and clustered CTCs, our data showed that HNC patients can be identified 4-6 months prior to developing clinical/radiographically evident metastasis. In these patients, a window for treatment escalation could become a possibility. In a proof of concept study, using novel culture formulations and hypoxic conditions (1-2% O2), we were able to demonstrate, for the first time, short-term patient derived CTC cultures ex vivo from 7/18 HNC samples (4/7 HPV-positive, oropharyngeal) in a clinically relevant time period. Expanding CTCs outside the patient’s body allows for the recapitulation of the molecular diversity present within the tumour, understanding the disease progression and testing of therapies. Recent advancements have shown that PD-1 immune checkpoint therapies have durable responses in metastatic HNC patients who fail 1st and 2nd line therapies. Our preliminary data suggests PD-L1 is frequently expressed on HNC CTCs, and an immunoscore may be able to stratify patients likely to respond to immunotherapy paving the way towards precision medicine.