Effects on DNA and RNA after the administration of two different schedules of 5-fluorouracil in colorectal cancer patients

The Rate of Infusion Represents an Important Aspect of Administering Anticancer Agents

Background

Infusion rate is one of the essential elements that should be included in all intravenous orders. Patients may experience adverse consequences or risks associated with inappropriate infusion. Meanwhile, there is growing pressure on the chemotherapy unit to deliver treatment quickly, efficiently, and safely, and thus it is very necessary to improve the chemotherapy process and service to cancer patients. Clinicians should consider how to further standardize infusion therapy, and innovate new infusion strategies to increase efficacy, reduce toxicity, improve patient satisfaction and save health resource costs. Sporadic studies have evaluated the effects of infusion rates of anticancer agents on clinical outcomes, economic benefits, and administration efficiency. However, an update review has not been available.

Methods

Relevant literature was identified by search of PubMed until September 2023.

Results

Infusion rates may have significant effect on the efficacy of anticancer agents (e.g., methotrexate, fluorouracil, and arsenic trioxide). Slow infusion is safer for platinum compounds, doxorubicin and carmustine, whereas fast infusion is safer than slow infusion of gemcitabine. Optimal flow rates of paclitaxel and fluorouracil are based on the balance between multiple risks of toxicity. Optimal infusion rate may bring economic benefits. If efficacy and safety are not compromised, shortened infusion may result in higher patient satisfaction, improved institutional efficiency and more nursing time available for other activities (e.g., biosimilar products, endostar). Other concerns about infusion rate include clinical indications (eg, paclitaxel and rituximab, methotrexate), severity and type of hypersensitivity reactions (e.g., platinum compounds), formulation features (e.g., paclitaxel, doxorubicin), and genetic polymorphism (e.g., gemcitabine, methotrexate).

Conclusion

The latest knowledge of infusion rate concerns will enhance the appropriateness and accuracy in intravenous administration. Interdisciplinary teams should collaborate and implement relevant risk management and healthcare policy. It is worthwhile to conduct comparative studies of intravenous therapy with different infusion speeds.

Retrospective study evaluating the safety of administering pegfilgrastim on the final day of 5-fluorouracil continuous intravenous infusion

BACKGROUND

Pegfilgrastim, a long-acting granulocyte-colony-stimulating factor used to prevent neutropenia, is not indicated for administration within 24 h of completion of chemotherapy. The safety of administering pegfilgrastim in gastrointestinal cancer chemotherapy regimens containing continuous intravenous infusion of 5-fluorouracil (5-FUCI) on the day of completion of 5-fluorouracil has not been adequately studied.

METHODS

An institutional review board-approved retrospective analysis of patients with a gastrointestinal malignancy receiving pegfilgrastim on the final day of 5-FUCI was conducted. The primary end point was to determine the incidence of grade 3 and grade 4 neutropenia and febrile neutropenia when pegfilgrastim was administered on the final day of 5-FUCI. The secondary endpoint was to determine rate of dose reductions and treatment delays.

RESULTS

A total of 300 patients were reviewed from January 2010 to May 2017. The most common cancers were colorectal (25%) and pancreatic (60%), with 77% of patients having late stage disease. The risk of a patient developing grade 3 neutropenia was 0.010 (95% CI 0.002-0.029) and grade 4 neutropenia was 0.007 (95% CI 0.001-0.024). The risk of febrile neutropenia was 0.007 (95% CI 0.001-0.024). The risks of treatment delay and treatment reduction were 0.013 (95% CI 0.004-0.034) and 0.010 (95% CI 0.002-0.029), respectively.

CONCLUSION

The low risk of grade 3 and grade 4 neutropenia, febrile neutropenia, as well as dose delays and/or reduction suggests that pegfilgrastim can be administered on the final day of 5-FUCI. Limitations of this study were that it was retrospective in nature and was conducted at a single institution.

Folate pathway genes linked to mitochondrial biogenesis and respiration are associated with outcome of patients with stage III colorectal cancer

5-fluorouracil in combination with the folate leucovorin is the cornerstone in treatment of colorectal cancer. Transport of leucovorin into cells, and subsequent metabolic action, require expression of several genes. The aim was to analyze if tumoral expression of genes putatively involved in leucovorin transport, polyglutamation, or metabolism was associated with outcome of patients with stage III colorectal cancer treated with adjuvant chemotherapy. A total of 363 stage III colorectal cancer patients who received adjuvant bolus 5-fluorouracil + leucovorin alone, or in combination with oxaliplatin according to Nordic bolus regimes were included. Expression of 11 folate pathway genes was determined in tumors using quantitative real-time polymerase chain reaction and related to disease-free survival. The median follow-up time was 5 years. During follow-up, 114 (31%) patients suffered from recurrent disease. A high tumoral expression of the genes SLC46A1/PCFT, SLC19A1/RFC-1, ABCC3/MRP3, GGH, and MTHFD1L, which are involved in folate transport, polyglutamation, or metabolism, was associated with longer disease-free survival of the patients. Each of these genes either encodes mitochondrial enzymes or is being regulated by mitochondrial transcription factors. Expression of the SLC46A1/PCFT gene was most strongly associated with disease-free survival, regardless of treatment regimen. In conclusion, the results show that expression of folate pathway genes are associated with outcome of colorectal cancer patients treated with adjuvant 5-fluorouracil in combination with leucovorin. A prospective study needs to be conducted to determine if expression of these genes can be used to predict response to leucovorin and other folates that are now being tested in clinical studies. Moreover, there seems to be a link between folate metabolism and mitochondrial biogenesis and respiration that deserves further exploration.

Thymidine phosphorylase: the unforeseen driver in colorectal cancer treatment?

5-Fluorouracil- and leucovorin-based chemotherapy regimens are the backbone of colorectal cancer treatment. The addition of oxaliplatin, irinotecan and monoclonal antibodies to this backbone has largely improved clinical outcomes, but has also led to new questions, with conflicting data frequently reported in studies. Thymidine phosphorylase (TP) is a nucleoside-metabolizing enzyme involved in 5-fluorouracil pharmacokinetics, as well as inflammatory responses, neoangiogenesis and apoptosis. TP expression is regulated by hypoxia, inflammatory cytokines and antitumoral agents. We hypothesize that TP could be the unforeseen driver in the conflicting data observed with different regimens commonly used in colorectal cancer treatment. Greater comprehension of the role of this enzyme in tumor progression and pyrimidine metabolism may lead to more accurate, patient-tailored therapy.

Re-evaluation of cellular radiosensitization by 5-fluorouracil: high-dose, pulsed administration is effective and preferable to conventional low-dose, chronic administration

PURPOSE

It is widely believed that the anticancer drug 5- fluorouracil (5-FU) must be administered chronically and in low doses to maximize radiosensitization during chemoradiotherapy. The rationale is based upon cell experiments that assumed identical mechanisms of 5-FU action between low-dose chronic (LDC) and high-dose pulsed (HDP) exposures. Here we challenge the paradigm and demonstrate the effectiveness of HDP 5-FU as a radiosensitizer and the wide range of dose/time schedules that can be used to synergize with radiation as compared to the relatively restrictive protocols prescribed for current LDC administrations.

MATERIALS AND METHODS

Clonogenic survival of human glioblastoma and colon cancer cell lines, U87MG-VIII and HCT-116, respectively, was used to assess temporal and dose effects of 5-FU on radiosensitivity and in split-dose experiments to characterize changes in sublethal damage repair.

RESULTS

We show that HDP 5-FU administration does indeed radiosensitize both the highly radioresistant U87MG-VIII and HCT-116. Additionally, we show that this radiosensitization lasts for at least 24 h if cells are pre-irradiated with 2 Gy immediately after HDP 5-FU exposure as a result of a decrease in sublethal damage repair capacity for subsequent irradiations, suggesting the ideal combination of 5-FU bolus injection with fractionation radiotherapy schemes.

CONCLUSIONS

5-FU bolus administration protocols combined with radiation would not only help improve treatment outcomes and reduce development of 5-FU resistance, but it would greatly benefit patients by shortening clinical stays and lowering overall therapeutic costs.

Photochemistry and electrochemistry of anticancer uracils

The redox mechanism and electronic absorption behavior of a commercial anticancer drug, 5-fluorouracil (5-FU) and two potential anticancer drugs, 2-thiouracil (2-TU) and dithiouracil (DTU) have been investigated in a wide pH range by UV-Vis spectroscopy, cyclic voltammetry and differential pulse voltammetry. The effect of electrolytes, substituents, successive sweeps and potential scan rate on the voltammetric response of uracils was examined. Organized structure-activity relationships of these drugs were established on the basis of the results obtained from electronic absorption spectroscopy and cyclic voltammetry. The electrode reaction mechanism was suggested using the experimentally determined electrochemical parameters. The DNA binding propensity of uracils was found greater than the classical intercalator, proflavin and clinically used drug, epirubicin. Moreover, the results obtained through ab initio calculations for the oxidation potential of the three uracil derivatives were found in good agreement with the electrochemical results.

Predictors of survival and toxicity in patients on adjuvant therapy with 5-fluorouracil for colorectal cancer

The present study aimed at investigating whether the simultaneous evaluation of pharmacokinetic, pharmacogenetic and demographic factors could improve prediction on toxicity and survival in colorectal cancer patients treated with adjuvant 5-fluorouracil (5FU)/leucovorin therapy. One hundred and thirty consecutive, B2 and C Duke's stage colorectal cancer patients were prospectively enrolled. 5FU pharmacokinetics was evaluated at the first cycle. Thymidylate synthase (TYMS) 5′UTR and 3′UTR polymorphisms and methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C polymorphisms were assessed in peripheral leukocytes. Univariate and multivariate analyses were applied to evaluate which variables could predict chemotherapy-induced toxicity, disease-free survival (DFS) and overall survival (OS). Multivariate analysis showed that: (a) low 5FU clearance was an independent predictive factor for severe toxicity (OR=7.32; P<0.0001); (b) high-5FU clearance predicted poorer DFS (HR=1.96; P=0.041) and OS (HR=3.37; P=0.011); (c) advanced age was associated with shorter DFS (HR=3.34; P=0.0008) and OS (HR=2.66; P=0.024); (d) the C/C genotype of the MTHFR C677T polymorphism was protective against grade 3–4 toxicity (P=0.040); (e) none of the TYMS polymorphisms could explain 5FU toxicity or clinical outcome.

Liver-only metastatic colorectal cancer patients and thymidylate synthase polymorphisms for predicting response to 5-fluorouracil-based chemotherapy

We investigated the association between thymidylate synthase (TS) germline polymorphisms and response to 5-fluorouracil-based chemotherapy in 80 patients with liver-only metastatic colorectal cancer (MCRC). The tandem repeat polymorphism (VNTR) in TS 5′-untranslated region (5′-UTR), which consists of two (2R) or three (3R) 28-bp repeated sequences, with or without a G/C nucleotide change in 3R carriers (3G or 3C) and a 6-bp insertion/deletion (6+/6−) in the TS 3′-UTR, was studied. The distinction between high (2R/3G, 3C/3G and 3G/3G) and low (2R/2R, 2R/3C and 3C/3C) TS expression genotypes according to the 5′-UTR VNTR+G/C nucleotide change showed significant association with tumour response (P=0.01). In particular, high TS expression genotypes were found in 8 out of 34 patients (23.5%) with complete or partial response and in 24 out of 46 patients (52%) with stable disease and disease progression. Liver-only MCRC patients are a homogeneous and clinical relevant subgroup that may represent an ideal setting for studying the actual influence of TS polymorphisms.

Pharmacogenetic profiling in patients with advanced colorectal cancer treated with first-line FOLFOX-4 chemotherapy

PURPOSE

The objective is to investigate whether polymorphisms with putative influence on fluorouracil/oxaliplatin activity are associated with clinical outcomes of patients with advanced colorectal cancer treated with first-line oxaliplatin, folinic acid, and fluorouracil palliative chemotherapy.

MATERIALS AND METHODS

Consecutive patients were prospectively enrolled onto medical oncology units in Central Italy. Patients were required to have cytologically/histologically confirmed metastatic disease with at least one measurable lesion. Peripheral blood samples were used for genotyping 12 polymorphisms in thymidylate synthase, methylenetetrahydrofolate reductase, xeroderma pigmentosum group D (XPD), excision repair cross complementing group 1 (ERCC1), x-ray cross complementing group 1, x-ray cross complementing protein 3, glutathione S-transferases (GSTs) genes. The primary end point of the study was to investigate the association between genotypes and progression-free survival (PFS).

RESULTS

In 166 patients, ERCC1-118 T/T, XPD-751 A/C, and XPD-751 C/C genotypes were independently associated with adverse PFS. The presence of two risk genotypes (ERCC1-118 T/T combined with either XPD-751 A/C or XPD-751 C/C) occurred in 50 patients (31%). This profiling showed an independent role for unfavorable PFS with a hazard ratio of 2.84% and 95% CI of 1.47 to 5.45 (P = .002). Neurotoxicity was significantly associated with GSTP1-105 A/G. Carriers of the GSTP1-105 G/G genotype were more prone to suffer from grade 3 neurotoxicity than carriers of GSTP1-105 A/G and GSTP1-105 A/A genotypes.

CONCLUSION

A pharmacogenetic approach may be an innovative strategy for optimizing palliative chemotherapy in patients with advanced colorectal cancer. These findings deserve confirmation in additional prospective studies.

Polymorphisms in XRCC1, XRCC3, and CCND1 and Survival After Treatment for Metastatic Breast Cancer

Purpose

Single nucleotide polymorphisms (SNPs) in DNA repair and cell cycle control genes may alter protein function and therefore the efficacy of DNA damaging chemotherapy. We retrospectively evaluated the association of SNPs in DNA repair genes, XRCC1-01 (Arg399Gln) and XRCC3-01 (Thr241Met), and a cell cycle control gene, CCND1-02 (A870G), with progression-free survival (PFS) and breast cancer specific survival (BCSS) in patients with metastatic breast cancer (MBC).

Patients and Methods

SNPs in 95 patients with MBC enrolled onto one of five prospective clinical trials of high-dose chemotherapy and autologous stem-cell transplantation were evaluated using genotyping assays.

Results

For XRCC1-01, the hazard ratio (HR) for BCSS was 2.8 (95% CI, 1.60 to 5.00) and the HR for PFS was 2.0 (95%CI, 1.12 to 3.43). For XRCC3-01, the HR for BCSS was 2.0 (95%CI, 1.12 to 3.70) and the HR for PFS was 2.0 (95%CI, 1.09 to 3.59). For CCND1-02, the HR for BCSS was 1.8 (95%CI, 1.12 to 2.78) and the HR for PFS was 1.8 (95%CI, 1.15 to 2.85). Patients carrying one variant genotype (HR, 1.7; 95%CI, 1.07 to 2.82) or combinations of any two variant genotypes (HR, 4.7; 95% CI, 2.41 to 8.94) had significantly poorer BCSS compared with patients carrying zero variants. In multivariable analysis, XRCC1-01, presence of liver metastases, and bone metastases independently predicted BCSS. Combinations of any two variant genotypes were stronger independent predictors of BCSS and PFS than the presence of liver or bone metastases.

Conclusion

XRCC1-01, XRCC3-01, and CCND1-01 may be predictive of survival outcome in patients with MBC treated with DNA damaging chemotherapy.