Colorectal cancer (CRC) is the third most frequently diagnosed cancer in the world. More than half of all CRC patients will eventually develop metastases and require treatment accordingly, but few validated predictive factors for response to systemic treatments exist. In order to ascertain which patients benefit from specific treatments, there is a strong need for new and reliable biomarkers. We conducted a comprehensive search using the PUBMED database, up to December 2019, in order to identify relevant studies on predictive biomarkers for treatment response in metastatic CRC. We will herein present the currently used and potential biomarkers for treatment response and bring up-to-date knowledge on the role of circulating microRNAs, associated with chemotherapy and targeted therapy regimens used in metastatic CRC treatment. Molecular, tumor-related, disease-related, clinical, and laboratory predictive markers for treatment response were identified, mostly proposed, with few validated. Several circulating microRNAs have already proven their role of prediction for treatment response in CRC, but future clinical studies are needed to confirm their role as biomarkers across large cohorts of patients.

The status of predictive biomarkers in metastatic colorectal cancer is currently underdeveloped. Our study aimed to investigate the predictive value of six circulating exosomal miRNAs derived from plasma (miR-92a-3p, miR-143-3p, miR-146a-5p, miR-221-3p, miR-484, and miR-486-5p) for chemosensitivity, resistance patterns, and survival. Thirty-one metastatic colorectal cancer patients were selected before receiving first-line irinotecan- or oxaliplatin-based chemotherapy. Blood samples were harvested at baseline and 4–6 months after the initiation of chemotherapy. The levels of exosomal expression for each miRNA were analyzed by qPCR. Our results for patients receiving first-line FOLFOX showed significantly higher baseline levels of miR-92a-3p (p = 0.007 **), miR-146a-5p (p = 0.036 *), miR-221-3p (p = 0.047 *), and miR-484 (p = 0.009 **) in non-responders (NR) vs. responders (R). Of these, miR-92a-3p (AUC = 0.735), miR-221-3p (AUC = 0.774), and miR-484 (AUC = 0.725) demonstrated a predictive ability to discriminate responses from non-responses, regardless of the therapy used. Moreover, Cox regression analysis indicated that higher expression levels of miR-92a-3p (p = 0.008 **), miR-143-3p (p = 0.009 **), miR-221-3p (p = 0.016 *), and miR-486-5p (p = 0.019 *) at baseline were associated with worse overall survival, while patients expressing higher baseline miR-92a-3p (p = 0.003 **) and miR-486-5p (p = 0.003 **) had lower rates of progression-free survival. No predictive values for candidate microRNAs were found for the post-chemotherapy period. In line with these findings, we conclude that the increased baseline exosomal expression of miR-92a-3p and miR-221-3p seems to predict a lack of response to chemotherapy and lower OS. However, further prospective studies on more patients are needed before drawing practice-changing conclusions.

Currently, only a limited set of molecular traits are utilized to direct treatment for metastatic CRC (mCRC). The molecular classification of CRC depicts tumor heterogeneity based on gene expression patterns and aids in comprehending the biological characteristics of tumor formation, growth and prognosis. Additionally, it assists physicians in tailoring the therapeutic approach. Microsatellite instability (MSI-H)/deficient mismatch repair proteins (MMRd) status has become a ubiquitous biomarker in solid tumors, caused by mutations or methylation of genes and, in turn, the accumulation of mutations and antigens that subsequently induce an immune response. Immune checkpoint inhibitors (ICI) have recently received approval for the treatment of mCRC with MSI-H/MMRd status. However, certain individuals experience either initial or acquired resistance. The tumor-programmed cell death ligand 1 (PD-L1) has been linked to the ability of CRC to evade the immune system and promote its growth. Through comprehensive research conducted via the PUBMED database, the objectives of this paper were to review the molecular characteristics linked to tumor response in metastatic CRC in light of improved patients’ outcomes following ICI therapies as seen in clinical trials and to identify particular microRNAs that can modulate the expression of specific oncoproteins, such as PD-L1, and disrupt the mechanisms that allow the immune system to be evaded.

Background and Objectives: Sarcopenia, a condition characterized by muscle mass loss, is prevalent in up to 68% of rectal cancer patients and has been described as a negative prognostic factor, impacting overall survival and tumor response. While there are extensive data on rectal cancer globally, only a handful of studies have evaluated the role of sarcopenia in locally advanced rectal cancer (LARC). Our study aimed to investigate the relationship between sarcopenia, overall response rate, and toxicity in patients who underwent total neoadjuvant treatment (TNT) for LARC. Materials and Methods: We performed a retrospective study of patients with rectal cancer treated with TNT and surgery with curative intent between 2021 and 2023 at Prof. Dr. Ion Chiricuta Institute of Oncology, Cluj-Napoca. Sarcopenia was assessed on MRI images by measuring the psoas muscle area (PMA) at the level of the L4 vertebra before and after neoadjuvant therapy. The primary endpoints were the overall complete response rate (oCR) and acute toxicity. Results: This study included 50 patients with LARC. The oCR rate was 18% and was significantly associated with post-treatment sarcopenia (OR 0.08, p = 0.043). Patients who did not achieve a clinical or pathologic complete response had, on average, an 8% muscle loss during neoadjuvant therapy (p = 0.022). Cystitis and thrombocytopenia were significantly associated with post-treatment sarcopenia (p = 0.05 and p = 0.049). Conclusions: Sarcopenia and loss of psoas muscle during neoadjuvant therapy were negatively associated with tumor response in locally advanced rectal cancer. Thrombocytopenia and cystitis are more frequent in sarcopenic than non-sarcopenic patients undergoing neoadjuvant chemoradiation for rectal cancer.

Background: Febrile neutropenia (FN) remains one of the most challenging problems in medical oncology and is a very severe side effect of chemotherapy. Its late consequences, when it is recurrent or of a severe grade, are dose reduction and therapy delays. Current guidelines allow the administration of granulocyte-colony-stimulating factors (G-CSF) for profound FN (except for the case when a pegylated form of G-CSF is administrated with prophylactic intention) in addition to antibiotics and supportive care. Methods: This is a prospective study that included 96 patients with confirmed malignancy, treated with chemotherapy, who developed FN during their oncological therapy, and were hospitalized. They received standard treatment plus a dose of G-CSF of 16 µg/Kg/day IV continuous infusion. Results: The gender distribution was almost symmetrical: Male patients made up 48.96% and 51.04% were female patients, with no significance on recovery from FN (p = 1.00). The patients who received prophylactic G-CSF made up 20.21%, but this was not a predictive or prognostic factor for the recovery time from aplasia (p = 0.34). The median chemotherapy line where patients with FN were included was two and the number of previous chemotherapy cycles before FN was three. The median serological number of neutrophils (PMN) was 450/mm³ and leucocytes (WBC) 1875/mm³ at the time of FN. Ten patients possess PMN less than 100/mm³. The median time to recovery was 25.5 h for 96 included patients, with one failure in which the patient possessed grade 5 FN. Predictive factors for shorter recovery time were lower levels of C reactive protein (p < 0.001) and procalcitonin (p = 0.002) upon hospital admission and higher WBC (p = 0.006) and PMN (p < 0.001) at the time of the provoking cycle of chemotherapy for FN. The best chance for a shorter duration of FN was a short history of chemotherapy regarding the number of cycles) (p < 0.0001). Conclusions: Continuous IV administration of G-CSF could be an alternative salvage treatment for patients with profound febrile neutropenia, with a very fast recovery time for neutrophiles.