Oral fluoropyrimidine versus intravenous 5-fluorouracil for the treatment of advanced gastric and colorectal cancer: Meta-analysis

Current landscape of fecal microbiota transplantation in treating depression

Depression, projected to be the predominant contributor to the global disease burden, is a complex condition with diverse symptoms including mood disturbances and cognitive impairments. Traditional treatments such as medication and psychotherapy often fall short, prompting the pursuit of alternative interventions. Recent research has highlighted the significant role of gut microbiota in mental health, influencing emotional and neural regulation. Fecal microbiota transplantation (FMT), the infusion of fecal matter from a healthy donor into the gut of a patient, emerges as a promising strategy to ameliorate depressive symptoms by restoring gut microbial balance. The microbial-gut-brain (MGB) axis represents a critical pathway through which to potentially rectify dysbiosis and modulate neuropsychiatric outcomes. Preclinical studies reveal that FMT can enhance neurochemicals and reduce inflammatory markers, thereby alleviating depressive behaviors. Moreover, FMT has shown promise in clinical settings, improving gastrointestinal symptoms and overall quality of life in patients with depression. The review highlights the role of the gut-brain axis in depression and the need for further research to validate the long-term safety and efficacy of FMT, identify specific therapeutic microbial strains, and develop targeted microbial modulation strategies. Advancing our understanding of FMT could revolutionize depression treatment, shifting the paradigm toward microbiome-targeting therapies.

Nomogram for predicting neutropenia in patients with esophageal, gastric, or colorectal cancer treated by chemotherapy in the first cycle

OBJECTIVES

Development and validation of a predictive model including serum vitamin concentration to estimate the risk of chemotherapy-induced grade 3/4 neutropenia in esophageal cancer, gastric cancer, or colorectal cancer patients who receive the first cycle of chemotherapy.

METHODS

Data from 535 patients treated at the Affiliated Fuyang People's Hospital of Anhui Medical University from January 1, 2020, to March 2, 2022, were used to derive the predictive model. Least absolute shrinkage and selection operator regression analysis was performed to screen potential risk characteristics, and multivariate logistic regression was utilized to investigate efficient factors associated with chemotherapy-induced neutropenia. A nomogram was constructed using this logistic model. This nomogram was then tested on a temporal validation cohort containing 212 consecutive patients.

RESULTS

In the cohort of all 747 eligible patients, grade 3/4 neutropenia incidence was 45.2%. Age, Eastern Cooperative Oncology Group-performance status, neutrophil count, serum albumin, and hemoglobin data were entered into the final model. The performance of the final predictive nomogram was assessed by the area under the receiver operating characteristic curve in both the development and validation datasets. The calibration curves indicated that the estimated risks were accurate. Decision curve analysis for the predictive model exhibited improved clinical practicality.

CONCLUSION

In the present study, we established an accessible risk predictive model and identified valuable serum vitamin concentration parameters associated with chemotherapy-induced neutropenia. The predictive model may improve the grade 3/4 neutropenia risk prediction in patients with gastrointestinal malignancies who receive oxaliplatin- and fluoropyrimidine-based chemotherapy and help physicians make appropriate decisions for disease management.

Laherradurin Inhibits Tumor Growth in an Azoxymethane/Dextran Sulfate Sodium Colorectal Cancer Model In Vivo

Colorectal cancer (CRC) is the third most common neoplasia in the world. Its mortality rate is high due to the lack of specific and effective treatments, metastasis, and resistance to chemotherapy, among other factors. The natural products in cancer are a primary source of bioactive molecules. In this research, we evaluated the antitumor activity of an acetogenin (ACG), laherradurin (LH), isolated from the Mexican medicinal plant Annona macroprophyllata Donn.Sm. in a CRC murine model. The CRC was induced by azoxymethane-dextran sulfate sodium (AOM/DSS) in Balb/c mice and treated for 21 days with LH or cisplatin. This study shows for the first time the antitumor activity of LH in an AOM/DSS CRC model. The acetogenin diminished the number and size of tumors compared with cisplatin; the histologic studies revealed a recovery of the colon tissue, and the blood toxicity data pointed to less damage in animals treated with LH. The TUNEL assay indicated cell death by apoptosis, and the in vitro studies exhibited that LH inhibited cell migration in HCT116 cells. Our study provides strong evidence of a possible anticancer agent for CRC.

Sustained co-delivery of 5-fluorouracil and cis-platinum via biodegradable thermo-sensitive hydrogel for intraoperative synergistic combination chemotherapy of gastric cancer

Gastric cancer is the fifth most common cancer and the third leading cause of cancer death worldwide, posing a severe threat to human health. Surgical resection remains the most preferred option for gastric cancer treatment. However, for advanced gastric cancer, the curative effect of surgical resection is usually limited by the local recurrence, peritoneal carcinomatosis, or distal metastasis. Intraoperative chemotherapy is an attractive in situ adjuvant treatment strategy to reduce the recurrence and metastasis after surgical resection. Here, we designed a 5-fluorouracil (5-FU) and cis-platinum (DDP) co-delivery system based on a biodegradable temperature-sensitive hydrogel (PDLLA-PEG-PDLLA, PLEL) for intraoperative adjuvant combination chemotherapy of gastric cancer. This 5-FU + DDP/PLEL hydrogel system characterized by a special sol-gel phase transition in response to physiological temperature and presented sustained drug release in vitro and in vivo. A strong synergistic cell proliferation inhibition and apoptosis promotion of 5-FU + DDP/PLEL were observed against gastric cancer MKN45-luc cells. After intraperitoneal injection, the dual-drug loaded hydrogel formulation showed superior anti-tumor effects than the single-drug carrying hydrogels and combination of free 5-FU and DDP on the gastric cancer peritoneal carcinomatosis model. The use of hydrogel for dual-drug delivery had benefited to fewer side effects as well. What's more, we established a mouse model for postsurgical residual tumors and peritoneal carcinomatosis of gastric cancer, in which the intraoperative administration of 5-FU + DDP/PLEL also remarkably inhibited the local recurrence of the orthotopic tumors and the growth of the abdominal metastatic tumors, resulting in an extended lifetime. Hence, this developed dual-drug loaded hydrogel system has great potential in the intraoperative chemotherapy of gastric cancer, that suggests a clinically-relevant and valuable option for postsurgical management of gastric cancer.

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Intraoperative chemotherapy could reduce the recurrence and metastasis after surgical resection of gastroenteric tumors.

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5-FU and DDP co-delivery system based on PLEL was developed for intraoperative combination chemotherapy of gastric cancer.

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This dual-drug loaded hydrogel helped to improve synergistic anti-tumor effects and reduce adverse side effects in vivo.

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5-FU+DDP/PLEL could inhibit recurrence of orthotopic tumors and growth of abdominal metastatic tumors in gastric cancer.

Protective effect of polysaccharides isolated from the seeds of Cuscuta chinensis Lam. on 5-fluorouracil-induced intestinal mucositis in mice

Purpose:

To evaluate the protective effect of Cuscuta chinensis Lam. polysaccharides (PCCL) on 5-fluorouracil-(5-FU)-induced intestinal mucositis (IM) in mice.

Methods:

PCCL was orally administered at a dose of 20 mg·kg^–1 for 7 days and its protective effect on 5-FU-induced IM (5-FU, 50 mg·kg^–1 for 5 days) was evaluated by monitoring changes in body weight, degree of diarrhea, levels of tissue inflammatory factors (tumor necrosis factor α, interleukin 6, and interleukin 1β levels), apoptosis rates, and the expression levels of caspase-3, Bax and Bcl-2.

Results:

The severity of mucosal injury (as reflected by body weight changes, degree of diarrhea, height of villi, and damage to crypts) was significantly attenuated by PCCL administration. PCCL also reduced the levels of tissue inflammatory factors, the apoptosis rate, and the expression of caspase-3 and Bax, and increased Bcl-2 expression.

Conclusions:

PCCL administration may be significantly protective against 5-FU-induced IM by inhibiting apoptosis and regulating the abnormal inflammation associated with it.

Measurement of 5- fluorouracil, capecitabine and its metabolite concentrations in blood using volumetric absorptive microsampling technology and LC-MS/MS

5-fluorouracil (5-FU) and its oral formulation, capecitabine, are widely used in treating a range of malignancies, either alone or in combination with other antineoplastic drugs. Body surface area-based dosing is used for these agents, despite this approach leading to substantial variability in drug exposure and often resulting in either toxicity or treatment failure. Tailoring therapeutic regimens for individual patients using therapeutic drug monitoring (TDM) has been shown to significantly reduce toxicity and improve cancer outcomes. However, for optimum TDM, sample timing is crucial, along with the need for a venepuncture blood sample to obtain the plasma currently used for 5-FU measurement. In addition to complex blood sample handling requirements, large sample volume and frequent sampling required for pharmacokinetic analysis is another barrier to successfully implementing TDM in a healthcare setting. Microsampling is an alternative collection method to venepuncture, which, combined with the now readily available liquid chromatography mass spectrometry (LC-MS/MS) technology, overcomes the plasma-associated issues. It also has the significant advantage of enabling at home and remote sampling, thus facilitating 5-FU TDM in clinical practice. A LC-MS/MS method for simultaneous measurement of capecitabine, 5'-deoxy-5-fluorocytidine, 5'-deoxy-5-fluorouridine and 5-FU using Mitra® microsampling devices for sample collection was developed. A Shimadzu 8060 LC-MS/MS equipped with electrospray ionisation source interface, operated in positive and negative ion modes, with reversed-phase chromatographic separation was employed for sample analysis. Samples were extracted from Mitra® devices using acetonitrile containing stable isotope-labelled internal standards, sonicated, evaporated under vacuum and resuspended in 0.1 % formic acid before injection into the LC-MS/MS. Chromatographic separation was on a Luna Omega Polar C₁₈ (100 × 2.1 mm, 1.6 µm) column with gradient elution of 0.1 % formic acid in water and acetonitrile. Total run time was 5 min, with the injection volume of 1 µL. The intra and inter-day imprecision ranged from 3.0 to 8.1 and 6.3-13.3 % respectively. Accuracy ranged from 95 -114 % for all analytes. Lower limit of quantification with imprecision of < 19 % and accuracy between 89 and 114 % was 0.05 mg/L for 5-FU and 10 µg/L for other analytes. Assays were linear from 0.05 to 50 mg/L for 5-FU and 10-10,000 µg/L for all other analytes. Analytes were stable on Mitra® devices for up to 9 months at room temperature, 2 years at -30 ℃ and 3 days at 50 ℃. The method was successfully applied for the analysis of samples from patients undergoing cancer treatment with 5-FU and capecitabine. Microsampling using volumetric absorptive microsampling proved to be as reliable as conventional blood collection for 5-FU and capecitabine. This sampling technique may lead to less invasive and better-timed sample collection for TDM, supporting dose optimization strategy.

Retrospective Cohort Study of Intraoperative Administration of Sustained-Release 5-Fluorouracil Implants in Advanced Gastric Cancer Patients

Background: 5-fluorouracil (5-FU) is basically used in the field of postoperative chemotherapy of gastric cancer (GC), the goal of this study was to evaluate improvement of long-term survival rate among GC patients after the 5-FU implants treatment.

Methods: The study included 145 patients with gastric cancer who received postoperative chemotherapy with 5-FU implants and had complete follow-up information. According to the sex, age and clinical stage of 5-FU implants group, 74 patients were matched as the control group at the same time. In the study, we compared the 5-year overall survival rate with progression-free survival rate in the two groups, and the drug safety for both groups during the treatment was also compared.

Results: The median follow-up time was 85 months (range 60–116 months). 31 patients (21.38%) died of tumor recurrence in 5-FU implants group and 21 (28.38%) in control group. In the control group, metastatic lesions were found in the small intestine, left adrenal gland and peritoneum in three patients. The 5-year progression-free survival (PFS) rate was 79.71% in 5-FU group and 67.12% in control (p = 0.0045). The 5-year overall survival (OS) rate was 77.68% in 5-FU implants group and 64.87% in control (p = 0.0159). Both the 5-years OS and PFS rates in 5-FU group were better than control group without significant side effect.

Conclusions: 5-FU implants may improve 5-years OS and PFS rates after surgery in gastric cancer patients, while good safety profile suggests it could be reliable.

Lycorine inhibits cell proliferation, migration and invasion, and primarily exerts in vitro cytostatic effects in human colorectal cancer via activating the ROS/p38 and AKT signaling pathways

Colorectal cancer (CRC) is a life‑threatening malignant tumor of the digestive tract. Diverse gene mutations and complicated alterations to the signaling pathways in CRC lead to heterogeneity in response to chemotherapy. Moreover, anticancer drugs for CRC chemotherapy are limited due to adverse events. Therefore, developing more effective, tolerable and safe drugs for the treatment of CRC is important. The present study aimed to investigate the effect of lycorine on human CRC cell proliferation, migration, invasion, apoptosis, cell cycle distribution, as well as the underlying molecular mechanism. The crystal violet staining and MTT assay results demonstrated that lycorine suppressed cell proliferation in a dose‑ and time‑dependent manner in the three CRC cell lines, HCT116, LoVo and SW480. Similarly, verified by performing wound healing and Transwell assays, lycorine significantly inhibited HCT116 and LoVo cell migration and invasion in vitro compared with the control group. In LoVo cells, the protein expression levels of matrix metallopeptidases, snail family transcriptional repressor 1, Vimentin and N‑cadherin were significantly downregulated, whereas the protein expression levels of E‑cadherin were significantly upregulated by lycorine treatment compared with the control group. The Hoechst 33258 staining and flow cytometry assay results indicated that lycorine mediated its cytostatic effect on CRC cells potentially via inducing cell cycle arrest, but not apoptosis. Compared with the control group, lycorine significantly induced HCT116 cell cycle arrest at the G2/M phase, but significantly induced LoVo cell cycle arrest at the S and G2/M phases. Furthermore, lycorine significantly downregulated the protein expression levels of cyclin D1 and cyclin E1, but significantly increased p21 and Smad4 protein expression levels in HCT116 and LoVo cells compared with the control group. The intracellular reactive oxygen species (ROS) measurement results also indicated that compared with the control group, lycorine significantly induced ROS accumulation, and increased phosphorylated‑p38 expression levels and AKT phosphorylation. Collectively, the present study suggested that lycorine might induce cell cycle arrest and exert cytostatic effects potentially via activating ROS/p38 and AKT signaling pathways in CRC cells.

Quadruple-responsive nanoparticle-mediated targeted combination chemotherapy for metastatic breast cancer

The synergism of combination chemotherapy can only be achieved under specific drug ratios. Herein, hyaluronic acid (HA)-functionalized regenerated silk fibroin-based nanoparticles (NPs) were used to concurrently deliver curcumin (CUR) and 5-fluorouracil (5-FU) at various weight ratios (3.3 : 1, 1.6 : 1, 1.1 : 1, 1 : 1, and 1 : 1.2) to breast tumor cells. The generated HA-CUR/5-FU-NPs were found to have desirable particle sizes (around 200 nm), narrow size distributions, and negative zeta potentials (about -26.0 mV). Interestingly, these NPs showed accelerated drug release rates when they were exposed to buffers that mimicked the multi-hallmarks in the tumor microenvironment (pH/hydrogen peroxide/glutathione/hyaluronidase). The surface functionalization of NPs with HA endowed them with in vitro and in vivo breast tumor-targeting properties. Furthermore, we found that the co-loading of CUR and 5-FU in HA-functionalized NPs exhibited obvious synergistic anti-cancer, pro-apoptotic, and anti-migration effects, and the strongest synergism was found at the CUR/5-FU weight ratio of 1 : 1.2. Most importantly, mice experiments revealed that HA-CUR/5-FU-NPs (1 : 1.2) showed a superior anti-cancer activity against metastatic breast cancer compared to the single drug-loaded NPs and non-functionalized CUR/5-FU-NPs (1 : 1.2). Collectively, these results demonstrate that HA-CUR/5-FU-NPs (1 : 1.2) can be exploited as a robust nanococktail for the treatment of breast cancer and its lung metastasis.

Efficacy and Safety of Bevacizumab Plus Oxaliplatin- or Irinotecan-Based Doublet Backbone Chemotherapy as the First-Line Treatment of Metastatic Colorectal Cancer: A Systematic Review and Meta-analysis

INTRODUCTION AND OBJECTIVE

Guidelines recommend combined doublet backbone chemotherapy based on 5-fluorouracil and oxaliplatin (OX) or irinotecan (IR) as the first-line treatment options for metastatic colorectal cancer. However, it is still unknown which is better when combined with bevacizumab (BEV). This systematic review and meta-analysis were performed to compare BEV-IR with BEV-OX regimens in terms of efficacy and safety.

METHODS

We searched studies from databases including MEDLINE, EMBASE, CENTRAL, and conference papers. The outcomes were overall response rate, overall survival, progression-free survival, and the incidence of the most common adverse events. The dichotomous data were reported as the risk ratio (RR) and the survival outcomes were extracted as the hazard ratio with 95% confidence interval (CI).

RESULTS

Eleven studies including 5632 patients were identified. No difference was found in overall survival or overall response rate between BEV-IR and BEV-OX regimens. The pooled progression-free survival was significantly longer in the BEV-IR group than the BEV-OX group (hazard ratio = 0.92, 95% CI 0.87-0.98, p = 0.08). Compared with the BEV-OX group, the BEV-IR group was related to a higher risk of bleeding events (RR = 0.80, 95% CI 0.64-0.98, p = 0.03), venous thromboembolism (RR = 0.60, 95% CI 0.46-0.79, p = 0.0002), and diarrhea (RR = 0.71, 95% CI 0.62-0.80, p < 0.00001). Conversely, the BEV-OX group was related to a higher risk of thrombocytopenia (RR 2.39, 95% CI 1.67-3.42, p < 0.00001) and neuropathy (RR 3.80, 95% CI 1.90-7.64, p = 0.0002).

CONCLUSIONS

The BEV-IR regimen was superior in improving progression-free survival as the first-line treatment for metastatic colorectal cancer. The two different doublet regimens combined with BEV had their specific features of adverse events.

Distant Metastasis in Colorectal Cancer Patients-Do We Have New Predicting Clinicopathological and Molecular Biomarkers? A Comprehensive Review

Colorectal cancer (CRC) remains a serious health problem worldwide. Approximately half of patients will develop distant metastasis after CRC resection, usually with very poor prognosis afterwards. Because patient performance after distant metastasis surgery remains very heterogeneous, ranging from death within 2 years to a long-term cure, there is a clinical need for a precise risk stratification of patients to aid pre- and post-operative decisions. Furthermore, around 20% of identified CRC cases are at IV stage disease, known as a metastatic CRC (mCRC). In this review, we overview possible molecular and clinicopathological biomarkers that may provide prognostic and predictive information for patients with distant metastasis. These may comprise sidedness of the tumor, molecular profile and epigenetic characteristics of the primary tumor and arising metastatic CRC, and early markers reflecting cancer cell resistance in mCRC and biomarkers identified from transcriptome. This review discusses current stage in employment of these biomarkers in clinical practice as well as summarizes current experience in identifying predictive biomarkers in mCRC treatment.

Kanglaite injection plus fluorouracil-based chemotherapy on the reduction of adverse effects and improvement of clinical effectiveness in patients with advanced malignant tumors of the digestive tract: A meta-analysis of 20 RCTs following the PRISMA guidelines

BACKGROUND

The digestive tract malignancies are a series of malignant tumor with high morbidity and mortality. Traditional Chinese medicine (TCM) combined with chemotherapy drugs interventions have been applied for the treatment of malignant tumors in Asian countries for dacades. This study aimed to assess the effectiveness and safety on the combination of Kanglaite injection and fluorouracil-based chemotherapy for treating digestive tract malignancies.

PURPOSE

To assess the effectiveness and safety on the combination of Kanglaite injection and fluorouracil-based chemotherapy for digestive tract malignancies.

METHODS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed when conducting the meta-analysis. Randomized controlled trials (RCTs) of Kanglaite injection combined with fluorouracil-based chemotherapy in the treatment of digestive tract malignant tumors were selected and assessed for inclusion. RevMan 5.3 software (Cochrane Collaboration, Oxford, UK) was used for meta-analysis. The objective response rate (ORR) was defined as the primary endpoint, and the disease control rate (DCR), quality of life (QoL), and toxicities were the secondary outcomes.

RESULTS

20 RCTs enrolling 1339 patients with advanced digestive tract malignancies were included. The methodological quality of most included trials was low to moderate. Compared with fluorouracil-based chemotherapy alone, Kanglaite injection plus fluorouracil-based chemotherapy can improve DCR (risk ratio (RR) = 1.18, 95% confidence interval (CI) 1.11-1.25, P < .00001), ORR (RR = 1.35, 95% CI 1.18-1.54, P < .00001), QoL (RR = 1.58, 95% CI 1.35-1.85, P < .00001), and can reduce adverse drug reactions (ADRs) such as myelosuppression (RR = 0.33, 95% CI 0.25-0.43, P < .00001), leukopenia (RR = 0.31, 95% CI 0.22-0.43, P < .00001), thrombocytopenia (RR = 0.6, 95% CI 0.38-0.49, P = .03), neutropenia (RR = 0.26, 95% CI 0.12-0.55, P = .0005), anemia (RR = 0.41, 95% CI 0.23-0.75, P = .004), gastrointestinal reaction (RR = 0.35, 95% CI 0.27-0.46, P < .00001), nausea/vomiting (RR = 0.41, 95% CI 0.28-0.61, P < .00001), diarrhea (RR = 0.34, 95% CI 0.18-0.62, P = .0004), hepatotoxicity (RR = 0.28, 95% CI 0.17-0.47, P < .00001), neurotoxicity (RR = 0.58, 95% CI 0.41-0.82, P = .002), mucositis (RR = 0.59, 95% CI 0.29-1.21, P = .15).

CONCLUSION

Kanglaite injection combined with fluorouracil-based chemotherapy could remarkably improve the clinical effectiveness and reduce the adverse effects in patients with advanced malignant tumors of the digestive tract which may provide evidence to judge whether TCM is an effective and safe intervention for the digestive tract malignancies.

5-fluorouracil and other fluoropyrimidines in colorectal cancer: Past, present and future

5-Fluorouracil (5-FU) is an essential component of systemic chemotherapy for colorectal cancer (CRC) in the palliative and adjuvant settings. Over the past four decades, several modulation strategies including the implementation of 5-FU-based combination regimens and 5-FU pro-drugs have been developed and tested to increase the anti-tumor activity of 5-FU and to overcome the clinical resistance. Despite the encouraging progress in CRC therapy to date, the patients' response rates to therapy continue to remain low and the patients' benefit from 5-FU-based therapy is frequently compromised by the development of chemoresistance. Inter-individual differences in the treatment response in CRC patients may originate in the unique genetic and epigenetic make-up of each individual. The critical element in the current trend of personalized medicine is the proper comprehension of causes and mechanisms contributing to the low or lack of sensitivity of tumor tissue to 5-FU-based therapy. The identification and validation of predictive biomarkers for existing 5-FU-based and new targeted therapies for CRC treatment will likely improve patients' outcomes in the future. Herein we present a comprehensive review summarizing options of CRC treatment and the mechanisms of 5-FU action at the molecular level, including both anabolic and catabolic ways. The main part of this review comprises the currently known molecular mechanisms underlying the chemoresistance in CRC patients. We also focus on various 5-FU pro-drugs developed to increase the amount of circulating 5-FU and to limit toxicity. Finally, we propose future directions of personalized CRC therapy according to the latest published evidence.

Antitumor pharmacotherapy of colorectal cancer in kidney transplant recipients

Renal transplantation has become the sole most preferred therapy modality for end-stage renal disease patients. The growing tendency for renal transplants, and prolonged survival of renal recipients, have resulted in a certain number of post-transplant colorectal cancer patients. Antitumor pharmacotherapy in these patients is a dilemma. Substantial impediments such as carcinogenesis of immunosuppressive drugs (ISDs), drug interaction between ISDs and anticancer drugs, and toxicity of anticancer drugs exist. However, experience of antitumor pharmacotherapy in these patients is limited, and the potential risks and benefits have not been reviewed systematically. This review evaluates the potential impediments, summarizes current experience, and provides potential antitumor strategies, including adjuvant, palliative, and subsequent regimens. Moreover, special pharmaceutical care, such as ISDs therapeutic drug monitoring, metabolic enzymes genotype, and drug interaction, are also highlighted.

Capecitabine Versus Continuous Infusion Fluorouracil for the Treatment of Advanced or Metastatic Colorectal Cancer: a Meta-analysis

OPINION STATEMENT

Nowadays, systemic chemotherapy with intravenous (IV) 5-fluorouracil (5-FU) remains the most commonly prescribed treatment for metastatic colorectal cancers (CRC), in combination with other cytotoxic drugs. 5-FU can be administered through a bolus injection or continuous infusion (cIV), with the latter becoming the preferred administration method and standard of care in recent years. Oral fluoropyrimidines were developed to overcome challenges associated with the IV administration of 5-FU, among which capecitabine has become the most widely used one. However, although capecitabine and other oral fluoropyrimidine-based regimens are more convenient to administer, their efficacy and safety in comparison with IV 5-FU are not well understood. Results from recent randomized controlled trials, observational studies, and meta-analyses have been inconsistent. Safety, in particular, remains controversial. Our review, a first comprehensive meta-analysis comparing the efficacy and safety of cIV 5-FU with capecitabine, the two most widely used fluorouracil modalities in CRC, showed that cIV 5-FU-based regimens are associated with greater response rates compared with capecitabine-based regimens, with no difference in progression-free survival, time to treatment failure, overall survival, or disease-free survival between the two. Furthermore, cIV 5-FU-based regimens showed an improved safety profile compared with capecitabine-based regimens. Our findings suggest that cIV 5-FU remains a more effective and safer modality of fluorouracil administration than capecitabine, thus providing supporting evidence to guide clinical practice in the management of colorectal cancer.

Base excision repair capacity as a determinant of prognosis and therapy response in colon cancer patients

The DNA-damaging agent 5-fluorouracil represents the most commonly used chemotherapeutic drug for colorectal cancer patients. DNA lesions associated with 5-fluorouracil therapy are primarily repaired by base excision repair (BER) and mismatch repair (MMR) pathways. Published evidence suggests that the individual DNA repair capacity (DRC) may affect a patient's prognosis and response to chemotherapy. With this in mind, we designed a prospective study of which the main aim was to investigate BER-DRC in relation to 5-fluorouracil response as potential predictive and/or prognostic biomarker. BER-DRC was supplemented by a microsatellite instability (MSI) analysis which represents an indirect marker of MMR activity in the tumor. All parameters were measured in paired samples of tumor tissue and non-malignant adjacent mucosa of 123 incident colon cancer patients. Our results indicate that BER-DRC in non-malignant adjacent mucosa was positively associated with overall survival (P = 0.007) and relapse-free survival (P = 0.04). Additionally, in multivariate analysis, good therapy responders in TNM stage II and III with an elevated BER-DRC in mucosa exhibited better overall survival. Moreover, the overall survival of these patients was even better in the presence of a decreased BER-DRC in tumor tissue. The ratio of BER-DRC in tumor tissue over BER-DRC in mucosa positively correlated with advanced tumor stage (P = 0.003). With respect to MSI, we observed that MSI-high tumors were mostly localized in proximal colon; however, in our cohort, the MSI status affected neither patients' prognosis nor survival. In summary, the results of the present study suggest that the level of BER-DRC is associated with patients' survival. BER-DRC represents a potential prognostic biomarker, applicable for prediction of therapy response and useful for individual approach to patients.