Dynamic Evaluation of Liquid Biopsies in Patients with Recurrent or Metastatic Salivary Gland Tumor Histologies (DELISH)

Aim/goals:

1. To assess the fidelity of circulating tumor DNA (ctDNA) to recapitulate tissue genome profiles of salivary gland tumors in baseline plasma samples.
2. To correlate tumor burden dynamics as measured by RECIST 1.1 and ctDNA kinetics.
3. To identify genomic alterations associated with acquired resistance of salivary gland tumors exposed to targeted agents.

Summary:

Salivary gland tumors are a heterogeneous group of diseases arising from different locations including major salivary glands (parotid, submandibular and sublingual) and minor salivary glands. Patients diagnosed with recurrent or metastatic salivary gland tumors do not have standard of care therapies approved and are routinely excluded from head and neck cancer clinical trials. Thus, the optimization of treatment modalities in the recurrent or metastatic setting remains a cornerstone to improve long term outcomes. This study aims to evaluate the clinicopathological features, treatment outcomes and survival of patients diagnosed with recurrent or metastatic salivary gland tumors treated with non-cytotoxic therapies and to correlate them with the kinetics of ctDNA. We hypothesize that the kinetics of ctDNA may be associated with prognosis in recurrent or metastatic salivary gland cancer patients and its sequencing may help to unveil genomic alterations associated with therapeutic resistance or sensitivity to targeted agents. If successful, DELISH would support the implementation of a ctDNA approach to track tumor burden evolution, which could predict treatment resistance and identify further actionable alterations associated with treatment efficacy.