A real-world application of liquid biopsy (LB) in metastatic colorectal cancer (mCRC)

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Background: First-line decision making is the key to the successful management of mCRC patients (pts). RAS/BRAF status is essential to choose the best targeted agent. In hub centers, a not negligible proportion of pts referred from elsewhere may not have standard tissue-based (STB) molecular results available at the time of first oncologic visit (T0). LB may help circumvent these hurdles. Methods: A monoinstitutional prospective head-to-head comparison of LB versus (vs) STB testing was conducted in a real-world setting. Selection criteria included: mCRC with unknown RAS/BRAF status at T0, tissue from primary or metastases archived in external centers, no previous anti- EGFR agents. At T0, pts underwent plasma sampling for LB testing and procedure for tissue recovery. RAS/BRAF genotyping was carried out by droplet digital PCR on circulating-free (cf) DNA. Primary endpoint was the comparison of time to LB (T1) vs STB (T2) results. Secondary endpoints were the overall percent agreement (OPA), specificity, sensitivity, positive and negative predictive value (PPV and NPV) of LB. Urinary (u) cfDNA testing was also explored. Results: A total of 33 pts were included. Mean T1 was 7 (2-12) days (d) as compared to 22 (7-65) d mean T2. T2 included a mean time for tissue recovery of 17 d. The OPA between LB and STB analysis was 83%. Compared to STB testing, LB specificity and sensitivity were 90% and 80%, respectively, with a PPV of 94% and NPV of 69%. In detail, at STB and LB testing, RAS mutation was found in 50% and 43% of pts; BRAF mutation in 17% and 13%, respectively. LB results included 1 false positive and 4 false negative (FN). FN showed a significantly lower tumor burden (i.e. total tumor volume) at basal CT scan. Concordance between STB and ucfDNA testing was 89%, with a sensitivity of 83% and specificity of 100% recorded for ucfDNA analysis. Conclusions: Faster turnaround time, high concordance and accuracy are 3 key-points supporting the adoption of LB in routinary mCRC care, in particular when decision on first-line is urgent and tissue recovery from external centers may require a long time. Results should be interpreted with caution in LB wild-type cases with low tumor burden.

Ramucirumab: the long and winding road toward being an option for mCRC treatment

INTRODUCTION

Colorectal cancer (CRC) is one of the main causes of cancer-related morbidity and mortality worldwide. Mortality is most often attributable to metastatic disease. Despite the progress achieved so far, life expectancy continues to be limited in most patients. Ramucirumab, a most recent antiangiogenic drug, is vying in the race to metastatic CRC (mCRC) treatment since its approval by the Food and Drug Administration (FDA), based on the results of the RAISE study.

AREAS COVERED

This article reviews the role of ramucirumab in mCRC, including clinical indication, safety issues, and future perspectives.

EXPERT OPINION

The use of Ramucirumab in clinical practice is still limited, probably due to economic burden and the lack of specific biomarkers. Future efforts will be addressed to improve our knowledge in the use of this drug and better guide us in patients' care.