Qoppa as a new synthetic analytical marker to detect the oncological population at high risk of metastasis during follow-up and optimize the imaging test schedule

Introduction: Advanced cancers produce numerous soluble factors that affect the microcirculation of organs with high capillary density. This produces a response in these organs, whose pathophysiological biomarkers can indirectly alert us to the existence of premetastatic niches. We propose a new synthetic analytical marker called Qoppa to identify the population at highest risk of metastasis to more effectively schedule the follow-up imaging tests.

Methods: In this RESOLT prospective observational study, plasma samples were obtained from cancer patients to detect 11 biomarkers of response to soluble tumor factors using multiplex immunoassay with Luminex and to calculate 20 global analytical parameters related to prognosis. A clustering study was performed using Eucledean metrics and Ward method, followed by the creation of synthetic covariates for each cluster. Their potential as classifiers for the risk of death and the development of de novo metastasis was analyzed using ROC operator curves. Finally, their classifying role was related to the clinical impact using Kapplan–Meier and Cox analyses.

Results: Thirty patients were enrolled. The clustering study resulted in two clusters: the first with only 12 global parameters and the second with the 11 response biomarkers and the remaining 9 global parameters. The synthetic covariate Stigma was built from the first cluster, and the synthetic covariate Qoppa from the second cluster. While Stigma showed a poor performance as a classifier for death or the development of de novo metastasis, Qoppa was an acceptable classifier with an AUC of 0.78 for both events (cutoff: 4.775). Likewise, the Cox and Kapplan–Meier risk analysis showed that a high Qoppa population has a statistically significantly higher risk of death and metastasis.

Conclusion: Qoppa could help detect the cancer population at higher risk of metastasis or death during the follow-up. This could allow for optimal and early scheduling of imaging tests for detection of metastasis formation.