A case of 5-fluorouracil-induced peripheral neuropathy

Modified mesoporous silica nanocarriers containing superparamagnetic iron oxide nanoparticle, 5-fluorouracil or oxaliplatin, and metformin as a radiosensitizer, significantly impact colorectal cancer radiation therapy

This study investigates the anticancer effects of SPION-based silica nanoparticles carrying 5-fluorouracil (5-FU) or oxaliplatin (OX), and metformin (MET) on colorectal cancer cells. Nanocarriers were equipped with pH-responsive gold gatekeepers for controlled release, PEGylation for longer circulation, and folic acid (FA) for targeted delivery. The effects were evaluated by investigating cell viability, cellular uptake, flow cytometry, and clonogenic assay in vitro. The efficacy of the system was also tested in vivo on C57BL/6 mice bearing HT-29 tumors, and potential side effects were evaluated. Nanocarriers were synthesized with hydrodynamic diameters of 79.8 nm for 5-FU and 85.2 nm for OX; zeta potentials of -21 and -22 mV, respectively, and remained stable after 72 h. Encapsulation efficiencies were 85 % for 5-FU, 80 % for OX, and 83 % for MET, with loading capacities of 44 %, 38 %, and 41 %, respectively. Drug release in acidic buffer was 38.7 % for 5-FU, 32.8 % for OX, and 43.5 % for MET. MTT assay showed increased toxicity due to FA conjugation, while PEGylation reduced the hemolysis activity. Targeted nanocarriers demonstrated superior cellular uptake and tumor localization compared to non-targeted variants. The combination of 5-FU-MET and OX-MET nanocarriers with radiation therapy (RT) demonstrated the greatest effect on their antitumor activity, accompanied by minimal side effects indicating effective tumor targeting in vivo. MRI and CT imaging further supported these findings. This study underscores the synergistic impact of MET alongside RT on the inhibition of cancer cells and tumor growth for both targeted 5-FU and OX nanocarriers reflecting the significant radiosensitizing properties of MET.

The Impact of Omitting 5-FU Bolus From mFOLFOX6 Chemotherapy Regimen on Hematological Adverse Events Among Patients With Metastatic Colorectal Cancer

Background

Metastatic colorectal cancer (mCRC) is often treated with a mFOLFOX6 regimen. The 5-fluorouracil (5-FU) bolus is often omitted from the regimen to reduce the risk of hematological adverse events (AEs) in patients with poor performance status. We aimed to investigate the incidence of hematological AEs in Asian patients with mCRC who were treated with the mFOLFOX6 with and without 5-FU bolus dosing.

Methods

This retrospective chart review was conducted at King Chulalongkorn Memorial Hospital, Thailand from June 2021 to June 2022. The primary endpoints were hematological AEs. Secondary endpoints were any AEs. The comparison of continuous data was conducted with an independent t-test. The Chi-squared test was used to compare categorical data.

Results

From 110 patients, we found that hematological and non-hematological AEs of any grade in the two groups were not significantly different. However, patients in the bolus arm had a significantly lower absolute neutrophil count (ANC) than those in the non-bolus arm (mean difference = 43.13 (95% confidence interval (CI): 20.74, 65.51), P-value = 0.0002). A subgroup analysis in patients who received first-line treatment with mFOLFOX6 showed that the bolus arm had a significantly lower ANC (mean difference = 46.01 (95% CI: 19.99, 72.03), P-value = 0.0007).

Conclusions

mCRC patients who were treated with bolus 5-FU had lower ANC. The 5-FU bolus omission from the mFOLFOX6 regimen may be required in patients with a high risk of neutropenia.

Effect of the Cannabinoid Agonist WIN 55,212-2 on Neuropathic and Visceral Pain Induced by a Non-Diarrheagenic Dose of the Antitumoral Drug 5-Fluorouracil in the Rat

5-fluorouracil (5-FU) is an antineoplastic drug used to treat colorectal cancer, but it causes, among other adverse effects, diarrhea and mucositis, as well as enteric neuropathy, as shown in experimental animals. It might also cause neuropathic pain and alterations in visceral sensitivity, but this has not been studied in either patients or experimental animals. Cannabinoids have antimotility and analgesic effects and may alleviate 5-FU-induced adverse effects. Our aim was to evaluate the effects of the cannabinoid agonist WIN 55,212-2 on neuropathic and visceral pain induced by a non-diarrheagenic dose of 5-FU. Male Wistar rats received a dose of 5-FU (150 mg/kg, ip) and gastrointestinal motility, colonic sensitivity, gut wall structure and tactile sensitivity were evaluated. WIN 55,212-2 (WIN) was administered to evaluate its effect on somatic (50-100 µg ipl; 1 mg/kg, ip) and visceral (1 mg/kg, ip) sensitivity. The cannabinoid tetrad was used to assess the central effects of WIN (1 mg/kg, ip). 5-FU decreased food intake and body weight gain, produced mucositis and thermal hyperalgesia, but these effects were reduced afterwards, and were not accompanied by diarrhea. Tactile mechanical allodynia was also evident and persisted for 15 days. Interestingly, it was alleviated by WIN. 5-FU tended to increase colonic sensitivity whereas WIN reduced the abdominal contractions induced by increasing intracolonic pressure in both control and 5-FU-treated animals. Importantly, the alleviating effects of WIN against those induced by 5-FU were not accompanied by any effect in the cannabinoid tetrad. The activation of the peripheral cannabinoid system may be useful to alleviate neuropathic and visceral pain associated with antitumoral treatment.

Antitumor Profile of Combined Matricaria recutita Flower Extract and 5-Fluorouracil Chemotherapy in Sarcoma 180 In Vivo Model

Medicinal plants have been commonly associated with chemotherapeutic treatments, as an approach to reduce the toxicological risks of classical anticancer drugs. The objective of this study was to evaluate the effects of combining the antineoplastic drug 5-fluorouracil (5-FU) with Matricaria recutita flowers extract (MRFE) to treat mice transplanted with sarcoma 180. Tumor inhibition, body and visceral mass variation, biochemical, hematological, and histopathological parameters were evaluated. The isolated 5-FU, 5-FU+MRFE 100 mg/kg/day, and 5-FU+MRFE 200 mg/kg/day reduced tumor growth; however, 5-FU+MRFE 200 mg/kg/day showed a more significant tumor reduction when compared to 5-FU alone. These results corroborated with the analysis of the tumor histopathological and immunodetection of the Ki67 antigen. In the toxicological analysis of the association 5-FU+MRFE 200 mg/kg/day, an intense loss of body mass was observed, possibly as a result of diarrhea. In addition, spleen atrophy, with a reduction in white pulp, leukopenia and thrombocytopenia, was observed in the 5-FU groups alone and associated with MRFE 200 mg/kg/day; however, there was no statistical difference between these groups. Therefore, the MRFE 200 mg/kg/day did not interfere in myelosuppressive action of 5-FU. In hematological analysis, body and visceral mass variation and biochemical parameters related to renal (urea and creatinine) and cardiac (CK-MB) function, no alteration was observed. In biochemical parameters related to liver function enzymes, there was a reduction in aspartate transaminase (AST) values in the 5-FU groups alone and associated with MRFE 200 mg/kg/day; however, there was no statistical difference between these groups. Therefore, the MRFE 200 mg/kg/day does not appear to influence enzyme reduction. The results of this study suggest that the association between the 5-FU+MRFE 200 can positively interfere with the antitumor activity, promoting the antineoplastic-induced reduction in body mass, while minimizing the toxicity of chemotherapy.

Nuclear Folate Metabolism

Despite unequivocal evidence that folate deficiency increases risk for human pathologies, and that folic acid intake among women of childbearing age markedly decreases risk for birth defects, definitive evidence for a causal biochemical pathway linking folate to disease and birth defect etiology remains elusive. The de novo and salvage pathways for thymidylate synthesis translocate to the nucleus of mammalian cells during S- and G2/M-phases of the cell cycle and associate with the DNA replication and repair machinery, which limits uracil misincorporation into DNA and genome instability. There is increasing evidence that impairments in nuclear de novo thymidylate synthesis occur in many pathologies resulting from impairments in one-carbon metabolism. Understanding the roles and regulation of nuclear de novo thymidylate synthesis and its relationship to genome stability will increase our understanding of the fundamental mechanisms underlying folate- and vitamin B₁₂-associated pathologies.

A rat model of FOLFOX-induced neuropathy: effects of oral dimiracetam in comparison with duloxetine and pregabalin

BACKGROUND AND AIM

The FOLFOX family of chemotherapy regimens are hampered by the development of a painful neuropathy. Current clinical treatments are inadequate, and furthermore, the research of innovative drugs is strongly disadvantaged by the absence of a preclinical model based on the complete mixture of FOLFOX components. The aim of this study was to set up a rat model of FOLFOX-induced neuropathy in rats, validate its predictability by reference drugs, and evaluate the effectiveness of the new anti-neuropathic compound dimiracetam.

METHODS

Male Sprague-Dawley rats were treated intraperitoneally with the FOLFOX components (6 mg kg^-1 oxaliplatin, 50 mg kg^-1 5-FU, 90 mg kg^-1 leucovorin calcium salt) or oxaliplatin alone (6 mg kg^-1) on days 0, 7, 14, and 21, whereas a separate group received one more injection of FOLFOX on day 28. Pain behavioural measurements (paw pressure, cold plate, and electronic Von Frey tests) and motor coordination (Rota-rod test) were assessed before and after treatments. Behavioural, motor, neurological, and autonomic parameters (open field and Irwin tests) were evaluated.

RESULTS

FOLFOX reduced the pain threshold in response to mechanical noxious and thermal (cold) non-noxious stimuli beginning from day 14 up to day 42 comparably to oxaliplatin alone. A fifth FOLFOX injection enhanced the severity but not the duration of painful alterations. Spontaneous activity, behavioural, autonomic, and neurological functions were also affected, whereas the motor coordination was not altered. On day 22, duloxetine (15 mg kg^-1, per os), morphine (10 mg kg^-1, subcutaneously), or pregabalin (20 mg kg^-1, per os), acutely administered, reduced the FOLFOX-dependent hypersensitivity. Repeated treatments with dimiracetam (150 mg kg^-1, per os, twice daily, from day 22) significantly protected rats from FOLFOX-induced alterations of pain threshold as well as from autonomic and neurological impairments taking effect after 7 days treatment. Pregabalin repeatedly administered (20 mg kg^-1, per os, twice daily, from day 22) was less effective in reducing mechanical hypersensitivity.

CONCLUSION

A clinically consistent model of FOLFOX-induced neurotoxicity has been developed in rats. Dimiracetam fully reduced hypersensitivity and neurological alterations showing a relevant profile as anti-neuropathic resource.

Effect of radiotherapy and chemotherapy on the risk of mucositis during intensity-modulated radiation therapy for oropharyngeal cancer

PURPOSE

To define the roles of radiotherapy and chemotherapy on the risk of Grade 3+ mucositis during intensity-modulated radiation therapy (IMRT) for oropharyngeal cancer.

METHODS AND MATERIALS

164 consecutive patients treated with IMRT at two institutions in nonoverlapping treatment eras were selected. All patients were treated with a dose painting approach, three dose levels, and comprehensive bilateral neck treatment under the supervision of the same radiation oncologist. Ninety-three patients received concomitant chemotherapy (cCHT) and 14 received induction chemotherapy (iCHT). Individual information of the dose received by the oral mucosa (OM) was extracted as absolute cumulative dose-volume histogram (DVH), corrected for the elapsed treatment days and reported as weekly (w) DVH. Patients were seen weekly during treatment, and peak acute toxicity equal to or greater than confluent mucositis at any point during the course of IMRT was considered the endpoint.

RESULTS

Overall, 129 patients (78.7%) reached the endpoint. The regions that best discriminated between patients with/without Grade 3+ mucositis were found at 10.1 Gy/w (V10.1) and 21 cc (D21), along the x-axis and y-axis of the OM-wDVH, respectively. On multivariate analysis, D21 (odds ratio [OR] = 1.016, 95% confidence interval [CI], 1.009-1.023, p < 0.001) and cCHT (OR = 4.118, 95% CI, 1.659-10.217, p = 0.002) were the only independent predictors. However, V10.1 and D21 were highly correlated (rho = 0.954, p < 0.001) and mutually interchangeable. cCHT would correspond to 88.4 cGy/w to at least 21 cc of OM.

CONCLUSIONS

Radiotherapy and chemotherapy act independently in determining acute mucosal toxicity; cCHT increases the risk of mucosal Grade 3 toxicity ≈4 times over radiation therapy alone, and it is equivalent to an extra ≈6.2 Gy to 21 cc of OM over a 7-week course.