Neuropathologic study on chronic neurotoxicity of 5-fluorouracil and its masked compounds in dogs

Physiological and cognitive changes after treatments of cyclophosphamide, methotrexate, and fluorouracil: implications of the gut microbiome and depressive-like behavior

Introduction

Chemotherapy-induced cognitive impairment colloquially referred to as chemobrain is a poorly understood phenomenon affecting a highly variable proportion of patients with breast cancer. Here we investigate the association between anxiety and despair-like behaviors in mice treated with cyclophosphamide, methotrexate, and fluorouracil (CMF) along with host histological, proteomic, gene expression, and gut microbial responses.

Methods

Forced swim and sociability tests were used to evaluate depression and despair-like behaviors. The tandem mass tag (TMT) proteomics approach was used to assess changes in the neural protein network of the amygdala and hippocampus. The composition of gut microbiota was assessed through 16S rRNA gene sequencing. Finally, quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to evaluate changes in intestinal gap junction markers.

Results and discussion

We observed that CMF induced social and despair-like behavior in mice 96 hours following treatment. Proteomic analysis identified changes in various proteins related to progressive neurological disease, working memory deficit, primary anxiety disorder, and gene expression revealing increases in NMDA and AMPA receptors in both the hippocampus and the amygdala because of CMF treatment. These changes finally, we observed immediate changes in the microbial population after chemotherapy treatment, with a notable abundance of Muribaculaceae and Romboutsia which may contribute to changes seen in the gut.

[A case of acute leukoencephalopathy induced by a combination of 5-fluorouracil and metronidazole]

We describe a 66-year-old woman who received folinic acid, leucovorin, fluorouracil and oxaliplatin for advanced rectal carcinoma. These drugs were initiated on day 1, and a pelvic abscess was identified on day 7. Piperacillin-tazobactam was initially administered, but was changed to ceftriaxone and metronidazole on day 14 on the basis of antimicrobial susceptibility testing. On the following day, the patient reported blindness, and MRI of the brain showed signal abnormalities in the splenium of the corpus callosum on DWI, suggestive of metronidazole encephalopathy. Although the total body exposure was 2 g, metronidazole was discontinued. The patient developed coma a few days later, and MRI of the brain on day 26 showed high signal intensity extensively involving the white matter in the cerebrum as well as the brainstem and cerebellum. She died 37 days after the initial administration of the chemotherapy. Pathological studies demonstrated decreased staining intensity in the myelin sheath and multiple vacuolar alterations, consistent with toxicity induced by metronidazole and fluorouracil. Care should be taken when administering a combination of these drugs, even if the total body exposure to each drug is limited.

Diffusion-weighted MRI in neuro-oncology

Diffusion-weighted MRI (DW-MRI) provides image contrast dependent on the molecular movement of water. It has been most widely used in the diagnosis of cytotoxic edema secondary to acute cerebral ischemia, but has also proven useful in assessing tumor cellularity and grade, abscess formation, cysts and various forms of white matter disorders. Furthermore, DW-MRI is used to generate maps of subcortical white matter tracts and their relationship to structural brain lesions that may serve for preoperative planning and intraoperative guidance. We provide a comprehensive review of current practical applications of DW-MRI in the diagnosis and treatment of primary brain tumors, metastases and nonmetastatic neurologic complications of cancer. A detailed description of diffusion tensor imaging is beyond the scope of this review. We performed a comprehensive search of the PubMed database of the USA National Library of Medicine with use of various combinations of the following search terms: diffusion-weighted imaging, apparent diffusion coefficient, diffusion tensor imaging, diffusion tensor, brain, tumor, glioblastoma, lymphoma, primary CNS lymphoma, stroke, cancer, abscess, leukoencephalopathy, methotrexate, fluorouracil, capecitabine. We identified original articles and well-documented case reports of DW-MRI applications in patients with primary brain neoplasms, metastases and nonmetastatic neurologic complications that we judged to be of high impact on the field. We largely selected publications from the past 10 years, but did not exclude commonly referenced and highly regarded older publications. We also searched the reference lists of articles identified by this search strategy and selected those we judged relevant. Review articles are cited to provide readers with more details and more references than can be covered here.

Acute and late onset cognitive dysfunction associated with chemotherapy in women with breast cancer

BACKGROUND

Growing evidence supports cognitive dysfunction associated with standard dose chemotherapy in breast cancer survivors. We determined the incidence, nature, and chronicity of cognitive dysfunction in a prospective longitudinal randomized phase 3 treatment trial for patients with T1-3, N0-1, M0 breast cancer receiving 5-fluorouracil, doxorubicin, and cyclophosphamide with or without paclitaxel.

METHODS

Forty-two patients underwent a neuropsychological evaluation including measures of cognition, mood, and quality of life. Patients were scheduled to be assessed before chemotherapy, during and shortly after chemotherapy, and 1 year after completion of chemotherapy.

RESULTS

Before chemotherapy, 21% (9 of 42) evidenced cognitive dysfunction. In the acute interval, 65% (24 of 37) demonstrated cognitive decline. At the long-term evaluation, 61% (17 of 28) evidenced cognitive decline after cessation of treatment. Within this group of patients, 71% (12 of 17) evidenced continuous decline from the acute interval, and, notably, 29% (5 of 17) evidenced new delayed cognitive decline. Cognitive decline was most common in the domains of learning and memory, executive function, and processing speed. Cognitive decline was not associated with mood or other measured clinical or demographic characteristics, but late decline may be associated with baseline level of performance.

CONCLUSIONS

Standard dose systemic chemotherapy is associated with decline in cognitive function during and shortly after completion of chemotherapy. In addition, delayed cognitive dysfunction occurred in a large proportion of patients. These findings are consistent with a developing body of translational animal research demonstrating both acute and delayed structural brain changes as well as functional changes associated with common chemotherapeutic agents such as 5-fluorouracil.

Reversible findings of restricted diffusion in 5-flourouracil neurotoxicity

A 35-year-old woman presented with neurotoxicity correlated to an i.v. regimen of 5-fluorouracil as episodes of acute confusional state and abnormalities of symmetrically restricted diffusion in the periventricular white matter and corpus callosum. On discontinuing the medication, the areas of severely restricted diffusion had entirely resolved, with minimal residual T2 signal abnormality. In this case, immediate discontinuation of the chemotherapeutic agent apparently reversed the patient's symptoms and findings on MRI. The scant information available in the published literature regarding this phenomenon is reviewed with regard to 5-fluorouracil.

Local fluorouracil chemotherapy interferes with neural and behavioral recovery after brain tumor-like mass compression

In this study, we investigated the impact of intracerebral delivery of chemotherapy on functional recovery from focal cortical tissue displacement, characteristic of brain tumors. Unilateral focal brain compression was induced by epidural implantation of an inverted hemisphere-shaped bead over the sensorimotor cortex. Microinjections of a total of 1mg chemoagent fluorouracil or the same volume of saline were made into the compressed cortex. Behavioral tests of forelimb sensorimotor function were conducted during 4 weeks' observation. Rats subjected to any of the three types of lesions, saline microinjection plus cortical compression, chemoagent microinjection alone, or chemoagent microinjection combined with cortical compression, demonstrated significant behavioral deficits in several sensorimotor tasks, compared with saline-microinjected control animals. In placing tests, behavioral deficits elicited by each single treatment were worsened by combined treatment with chemoagent microinjection and focal cortical compression. Concurrently, local delivery of chemoagent into the compressed cortex induced increased cortical tissue loss, necrosis and apoptosis. These data indicate that local chemotherapy exacerbates compression-induced neurological impairment, and a model of controlled focal cortical compression may provide a valuable means to improve anti-cancer therapeutic designs with reduced deterioration of brain function.

A meta-analysis of the neuropsychological effects of adjuvant chemotherapy treatment in women treated for breast cancer

Given the improvement in mortality rates associated with breast cancer, the importance of understanding the long-term neuropsychological consequences of chemotherapy is becoming increasingly vital. This study applies meta-analytic techniques to the scant literature on the relationship between contemporary adjuvant chemotherapy treatment for breast cancer and cognitive dysfunction as examined through neuropsychological indices. Seven studies (involving more than 300 participants) were selected from over 200 potential articles, based on three inclusion criteria: presence of breast cancer, administration of chemotherapy treatment, and use of neuropsychological tests. From these, nine treatment-control comparisons were used to generate 129 Hedge's d effect sizes across the cognitive domains of simple attention, working memory short- and long-term memory, speed of processing, language, spatial abilities, and motor function. Small to medium cumulative effect sizes, showing diminished cognitive function for chemotherapy treatment groups compared to control groups, were obtained for each of the eight cognitive domains. Overall, these results suggest that women who undergo adjuvant chemotherapy as treatment for breast cancer may experience subtle yet consequential cognitive decline.

Intermediate dose 5-fluorouracil-induced encephalopathy

As an acute neurotoxicity, high dose 5-fluorouracil (5-FU)-induced encephalopathy is well-known, but encephalopathy associated with lower dose is rarely reported. Here, we report a case of a male with anal cancer who was treated with 5-FU 1000 mg/m(2), continuous infusion for 5 days q4 weeks. At the second and the fourth cycles of chemotherapy, sudden confusion, cognitive dysfunction and disorientation occurred during 5-FU infusion. They were accompanied by hyperammonemia in the absence of focal neurological deficits or structural abnormalities. These symptoms completely disappeared and the serum ammonia level returned to normal after discontinuation of 5-FU and conservative care. In order to investigate a possible deficit of dihydropyrimidine dehydrogenase (DPD), we checked its mRNA level before and after treatment using real-time PCR. The patient's pre-treatment level was 80% compared with reference group, and it was elevated up to 187% of initial after 5-FU treatment, implying that that his encephalopathy may be 5-FU catabolite type rather than DPD deficiency. In conclusion, we report that encephalopathy can develop even with the dose of 5-FU lower than ever reported, and it should be considered as a differential diagnosis for proper management.

Neurotoxic effects of alpha-fluoro-beta-alanine (FBAL) and fluoroacetic acid (FA) on dogs

In order to clarify the mechanism of the neurotoxicity of 5-FU and/or its masked compounds, we studied the effects of alpha-fluoro-beta-alanine (FBAL) and fluoroacetic acid (FA) on the formation of vacuolar changes in the dog cerebrum, using the dosage of 3.0 mg/kg/day of FBAL-HCl (FBAL x HCl) and 0.03 mg/kg/day of FA-Na (FA x Na), respectively. These 2 compounds were selected because they are the metabolites of 5-FU claimed to be responsible for the neurotoxic effects of 5-FU and/or its masked compounds, and we wanted to confirm their effects. Tegafur-uracil mixture (UFT) was used as a positive control drug for the formation of vacuolar changes in the dog cerebrum. All compounds were orally administered daily for 3 months to beagle dogs. Each study group consisted of 3 males. Neurotoxic signs such as hyperesthesia and/or excitement, as well as convulsions, were observed in both FBAL x HCl and FA x Na groups; these toxic signs were also found in the UFT group. Slight loss of body weight gain and of food consumption was observed in the FBAL x HCl and UFT groups. Neuropathologically, vacuolar changes were detected in several areas of the dog cerebrum following administration of FBAL x HCl, FA x Na or UFT. In terms of morphology, the neuropathological effects of these 2 drugs were very similar to those induced by UFT. In conclusion, we clearly showed that FBAL is one of the main substances that cause neurotoxic signs and neuropathological changes in dogs intoxicated by 5-FU or its masked compounds. Moreover, FA might be considered to be a causative factor in addition to FBAL.

Diffusion-weighted magnetic resonance imaging in early stage of 5-fluorouracil-induced leukoencephalopathy

We report a case of 5-fluorouracil (5-FU)-induced leukoencephalopathy in which magnetic resonance imaging (MRI) of the brain, including diffusion-weighted imaging (DWI), was performed serially. The initial T2-weighted and FLAIR images showed diffuse mild hyperintensity in bilateral deep cerebral white matter and corpus callosum, which on T1WI appeared as non-enhanced faint hypointensity. Isotropic DWI disclosed the abnormality as well-conspicuous diffuse hyperintensity with decreased ADC. Serial studies revealed that majority of the abnormal signal intensity on these sequences resolved, and the decreased ADC values approached normal. Some hyperintensity remained in the deep cerebral white matter and the splenium, but no further significant ADC change after normalization was noted. Measurement of ADC along the three orthogonal directions showed the presence of directional dependence of diffusion throughout the length of study. These findings suggest that early stage of 5-FU-induced leukoencephalopathy is associated with reversible restricted diffusion and preservation of anisotropy. Diffusion-weighted imaging may be useful for the diagnosis.

A case of neurotoxicity following 5-fluorouracil-based chemotherapy

5-Fluorouracil (5-FU) is a commonly used chemotherapeutic agent. However, its neurotoxicity is rare and not well recognized. We report a case of 5-FU neurotoxicity with organic brain syndrome and progression to multifocal leukoencephalopathy in a 44-year-old male patient having malignant gastrointestinal stromal tumor. 5-FU-induced neurotoxicity should, therefore, be considered as an important differential diagnosis in cancer patients with neurological abnormality and history of chemotherapy.

Simultaneous determination of F-beta-alanine and beta-alanine in plasma and urine with dual-column reversed-phase high-performance liquid chromatography

F-beta-Alanine and beta-alanine were detected in plasma and urine samples with fluorescence detection of orthophthaldialdehyde derivatives of F-beta-alanine and beta-alanine after separation with dual-column reversed-phase HPLC. The detection limits of F-beta-alanine and beta-alanine in the HPLC system were approximately 0.3 and 0.7 pmol, respectively. The procedure proved to be very reproducible with intra-assay RSDs and inter-assay RSDs being less than 8%. The usefulness of the method was demonstrated by the analysis of the F-beta-alanine and beta-alanine concentrations in plasma and urine samples from tumor patients treated with S-1 (Tegafur, 5-chloro-2,4-dihydroxypyridine and potassium oxonate in a molar ratio of 1:0.4:1).

5-Fluorouracil and levamisole exacerbate demyelination in susceptible mice infected with Theiler's virus

A multifocal inflammatory leukoencephalopathy is associated with the administration of 5-fluorouracil (5-FU), a pyrimidine analogue, and levamisole (LE), an immunomodulator, in patients receiving adjuvant therapy for colon cancer. Cerebral biopsy demonstrated features indistinguishable from multiple sclerosis. We tested whether administration of these agents directly resulted in inflammatory demyelination in mice or whether they exacerbated demyelination in a host predisposed to myelin injury. We used mice intracerebrally infected with Theiler's murine encephalomyelitis virus (TMEV) which serves as an excellent model for multiple sclerosis. Varying dosages of 5-FU (240 micrograms-2.4 mg) and LE (40 micrograms-1 mg) were administered alone or in combination on a fixed schedule to 52 normal SJL mice and 61 Theiler's virus-infected mice (51 SJL/J mice susceptible to demyelination; 10 C57BL10 mice resistant to demyelination). Controls included 6 noninfected SJL and 26 infected mice (16 susceptible; 10 resistant) treated with phosphate-buffered saline (PBS). Inflammation or demyelination was not detected in brains or spinal cords of noninfected SJL mice treated with 5-FU and/or LE. TMEV-susceptible SJL mice treated with LE alone or in combination with 5-FU demonstrated more extensive inflammation and demyelination at Day 45 than mice treated with PBS. Demyelination was accelerated in infected animals treated with these agents at 45 days but at 70 days a significant difference in extent of demyelination was no longer appreciated between treatment and control groups. Treatment with 5-FU and LE did not convert normally resistant TMEV-infected C57BL/10 mice to demyelination. These experiments support the hypothesis that 5-FU and LE may exacerbate inflammatory demyelination in a susceptible host.

5-Ethynyluracil (GW776): effects on the formation of the toxic catabolites of 5-fluorouracil, fluoroacetate and fluorohydroxypropionic acid in the isolated perfused rat liver model

We studied the effects of 5-ethynyluracil (GW776), a potent inactivator of dihydropyrimidine dehydrogenase, on the metabolism of 5-fluorouracil (5-FU), in particular with respect to formation of the toxic compounds fluoroacetate (FAC) and 2-fluoro-3-hydroxypropionic acid (FHPA), using fluorine-19 nuclear magnetic resonance and the isolated perfused rat liver model. Livers were perfused with 5-FU alone at a dose of 15 mg kg(-1) body weight or with 5-FU + GW776 at doses of 15 mg 5-FU kg(-1) body weight and 0.5 mg GW776 kg(-1) body weight injected 1 h before 5-FU. All 5-FU was metabolized in experiments with 5-FU alone whereas unmetabolized 5-FU represented 94% of the fluorinated compounds measured in experiments with 5-FU + GW776. GW776 modulated both the catabolic and the anabolic pathways of 5-FU, the most striking effect being on the degradative pathway. The amount of 5-FU catabolites decreased by a factor of 27 in the presence of GW776. The modulator led to a decrease in alpha-fluoro-beta-alanine (FBAL) formation by a factor of approximately 110, while fluoride ion formation decreased by a factor of approximately 10. By strongly lowering the metabolism of 5-FU into FBAL, GW776 circumvented the transformation of FBAL into toxic FAC and FHPA. 5-FU anabolites increased by a factor of approximately 7 in the presence of GW776. The level of free fluoronucleotides and 5-fluorouridine-5'-diphosphate sugars was increased up to fivefold. No incorporation of 5-FU into RNA could be measured in experiments with 5-FU alone whereas, although low (0.1% of 5-FU injected dose), it was detectable in experiments with 5-FU + GW776. These results suggest that GW776 may be useful for attenuating the not very common but serious cardiotoxic and/or neurotoxic side-effects of 5-FU that are probably due to FBAL metabolites.

5-Ethynyluracil (776C85): protection from 5-fluorouracil-induced neurotoxicity in dogs

5-Ethynyluracil (776C85) is a potent mechanism-based inactivator of dihydropyrimidine dehydrogenase (DPD), the enzyme that catalyzes the rapid catabolism of 5-fluorouracil (5-FU). Because catabolism is the major route for 5-FU clearance, we studied the effect of 5-ethynyluracil on the pharmacokinetics and toxicity of continuous i.v. 5-FU infusion in the dog. 5-FU at 40 mg/kg/24 hr resulted in a steady-state plasma 5-FU concentration of 1.3 microM and was fatal with dogs dying from apparent neurotoxicity. 5-Ethynyluracil lowered the total clearance of 5-FU from 9.9 to 0.2 L/hr/kg and enabled 1.6 mg/kg/24 hr 5-FU to achieve a steady-state plasma 5-FU concentration of 2.4 microM with no apparent toxicity. 5-FU at 4 mg/kg/24 hr achieved a steady-state plasma 5-FU concentration of 5.3 microM and produced only mild gastrointestinal disturbances in 5-ethynyluracil-treated dogs. Thus, a catabolite of 5-FU appears to be responsible for the 5-FU-induced neurotoxicity in dogs.

Cerebral demyelination with 5-fluorouracil and levamisole

We report a patient who developed multifocal cerebral demyelination with the use of 5-fluorouracil, levamisole, and leucovorin as adjuvant treatment for intestinal adenocarcinoma. The clinical features were acute confusion, restlessness, ataxia, and slurred speech. Magnetic resonance imaging revealed multifocal enhancing white matter lesions. Brain biopsy showed a well-demarcated area of demyelination in cerebral white matter. The patient improved clinically and radiologically after cessation of chemotherapy and a short course of steroids. There have been only 4 previously reported cases of multifocal leukoencephalopathy related to the use of combination 5-fluorouracil and levamisole. The extensive use of these agents as adjuvant treatment for colorectal carcinoma may result in more frequent recognition of this form of neurological toxicity.

A mathematical model of the kinetics and tissue distribution of 2-fluoro-beta-alanine, the major catabolite of 5-fluorouracil

2-Fluoro-beta-alanine (FBAL) is the major metabolite of 5-fluorouracil (FUra), one of the most widely used anticancer drugs. It has been suggested previously that FBAL and/or its metabolites may have a role in the hepatotoxicity, neurotoxicity and cardiotoxicity resulting from FUra chemotherapy. Studies in patients and experimental animals have demonstrated that FBAL has a prolonged elimination compared with the parent drug, FUra. In the present manuscript, a mathematical model is developed for the kinetics and tissue distribution of FBAL. This model is based on recently published data from a study of the pharmacokinetics and disposition of FBAL in rats (Zhang et al., Drug Metab Dispos 20: 113-119, 1992). Satisfactory agreement was achieved between predicted and measured values, permitting an accurate evaluation of the kinetic and distribution parameters for FBAL. This model indicates that: (1) FBAL accumulates in several tissues including brain, heart, spleen, and enterohepatic system; and (2) enterohepatic circulation of FBAL and its bile acid conjugates has an important role in FBAL kinetics and distribution as demonstrated by a model in which enterohepatic circulation parameters were deleted.

Multifocal inflammatory leukoencephalopathy with 5-fluorouracil and levamisole

A cerebral demyelinating disease developed in 3 patients during adjuvant therapy with 5-fluorouracil and levamisole for adenocarcinoma of the colon. None of the patients had evidence of metastatic disease or prior neurological disease. The duration of chemotherapy before onset of neurological symptoms ranged from 15 to 19 weeks. The total dose of 5-fluorouracil was 9.7 to 15.7 gm. The total dose of levamisole was 2.7 to 3.75 gm. Two patients presented with a subacute (2-3 weeks) progressive decline in mental status and ataxia. The third patient had two unexplained episodes of loss of consciousness. In each, magnetic resonance imaging with gadolinium demonstrated prominent multifocal enhancing white matter lesions. Cerebral biopsy was performed stereotaxically in 2 patients. The morphological features were those of active demyelinating disease. The myelin loss was associated with numerous dispersed as well as vasocentric macrophages, sparing of axons, and perivascular lymphocytic inflammation. Electron microscopy confirmed the light microscopic findings. All 3 patients improved after cessation of chemotherapy and a short course of corticosteroid therapy. Our patients represent the first reported examples of an inflammatory leukoencephalopathy associated with the administration of 5-fluorouracil and levamisole. This syndrome may represent the pathological basis for 5-fluorouracil neurotoxicity, although we cannot completely exclude the role of levamisole.

Experimental neurotoxicity of 5-fluorouracil and its derivatives is due to poisoning by the monofluorinated organic metabolites, monofluoroacetic acid and alpha-fluoro-beta-alanine

Two metabolites of 5-fluorouracil (FU), monofluoroacetic acid (FA) and alpha-fluoro-beta-alanine (FBAL), were continuously administered into the left ventricle of the brain in cats for up to 1 month to investigate the mechanism of neurotoxicity of FU and its derivatives. The cumulative doses of FU and FBAL over a 1-month period were 1.5-45 mg (20 cats) and 0.2-4.8 mg (21 cats), respectively. As controls for each experimental group, acetic acid (AA) and beta-alanine (BAL) were administered. In terms of survival time in relation to the cumulative dose and molecular weight, FBAL was more toxic than FA. Neuropathologically, two types of change, vacuoles and necrosis/softening-like change, were found. The vacuoles were 20-50 microns in diameter, and distributed mainly in the cerebellar nuclei, white matter and the tectum and tegmentum of the brain stem in both experimental groups. Electron microscopically, these vacuoles were due to splitting of the myelin intraperiod line or separation between the axon and the innermost layer of myelin. Necrosis/softening-like change occurred preferentially in the FBAL group and was located symmetrically in the superior and inferior colliculi, oculomotor nuclei and thalamus. Both types of neuropathological change, especially those in the FBAL group, were similar to those found in cats orally administered with FU and its derivatives.(ABSTRACT TRUNCATED AT 250 WORDS)

Low dose 1-hexylcarbamoyl-5-fluorouracil (HCFU) recommended for cirrhotic patients with hepatocellular carcinoma

The metabolism of 1-hexylcarbamoyl-5-fluorouracil (HCFU), a drug prescribed for treating patients with hepatocellular carcinoma (HCC), was studied in relation to liver function, with the objective of clarifying the occurrence of any adverse side-effects on the central nervous system. Twenty-five HCC patients were administered 3.4 mg/kg HCFU once orally, after which the blood levels of HCFU and its derivatives (5-FU, CPEFU, CPRFU, HHCFU, OHCFU and F-beta-alanine) were serially measured using high performance liquid chromatography. The area under the concentration curve (AUC) of HCFU in the group of ICG R15 greater than or equal to 30% (group 2) was 5.35 +/- 1.73 h.micrograms/ml, a value which was significantly higher than the 2.60 +/- 1.19 h.micrograms/ml recorded for the group of ICG R15 less than 30% (group 1) (P less than 0.001). The AUC of HCFU had a significant positive correlation with the value of ICG R15 (P = 0.002) or the serum total bilirubin (P = 0.0005). The AUC of 5-FU showed no difference between the two groups. The AUC of CPRFU in group 2 was 0.16 +/- 0.25 h.micrograms/ml, a value significantly lower than the 0.48 +/- 0.39 h.micrograms/ml in group 1 (P = 0.023). There was no correlation between the AUC of other derivatives and the markers of liver function. These data suggest that, in patients with advanced cirrhosis, the accumulation of HCFU is related to the occurrence of side-effects from the administered drug, ingested over a long-term period. Therefore, when HCFU is given to cirrhotic patients with both HCC and 30% or more ICG R15, a careful monitoring for side-effects is required.

Leukoencephalopathy following treatment with carmofur: a case report and review of the Japanese literature

A 53-year-old woman was treated with 5 courses of CAP treatment following operation for FIGO Stage Ia cancer of the ovary in September 1986. And in April 1987, she started an oral adjuvant chemotherapy with 400 mg/day of carmofur. In early June, she developed vertigo and dysarthia and was hospitalized. A CT scan showed low-density areas adjacent to both lateral ventricles, and an EEG revealed abnormally slow waves. She improved gradually after carmofur was discontinued and left the hospital in October 1987. There have been 24 reported cases of leukoencephalopathy because of carmofur in Japan, but the pathophysiological mechanism involved is not known. Since it is more common in women than in men, its incidence will probably increase in gynecological patients. Therefore, we must be on the lookout for central nervous system signs and symptoms in patients receiving adjuvant chemotherapy with carmofur.

Subacute neurotoxicity of 5-fluorouracil and its derivative, carmofur, in cats

The subacute neurotoxicity of 5-fluorouracil (FU) and its derivative, carmofur (HCFU), in cats was morphologically examined; both these drugs were orally administered once daily for a maximum of three months. The dosis of FU and HCFU was 2 mg/kg/day and 10 mg/kg/day, respectively. Both FU and HCFU induced two sorts of changes in the brain, i.e., vacuolation and softening-like change. The former was distributed in the white matter of the cerebrum and cerebellum and in areas of the gray matter such as the tectum and tegmentum of the brain stem, while the latter was distributed exclusively in the gray matter of the tectum and tegmentum of the brain stem. The tectum, especially the inferior colliculus, was most frequently affected by both types of change. Ultrastructurally, vacuolation was found to be due to lamellar splitting or separation between the axon and innermost myelin layer. These findings were compared with those in dogs and as the etiopathogenesis vacuolation due to direct toxic effect of FU or its metabolites to myelin and softening-like change due to local circulatory disturbance caused by vacuolation were proposed.

Subacute leucoencephalopathy induced by carmofur, a 5-fluorouracil derivative

Three cases of leucoencephalopathy induced by carmofur (1-hexylcarbamoyl-5-fluorouracil), an antineoplastic derivative of 5-fluorouracil are reported and the literature is reviewed. Initial symptoms were unsteady gait and dementia developing several weeks or months after carmofur had been started. Symptoms increased gradually even after stopping the drug. Severe encephalopathy with confusion, delirium or coma appeared frequently. Symptoms were usually reversible but death occasionally occurred. The EEG showed marked slowing. Computed tomography of the brains of severely intoxicated patients showed marked hypodensity of the entire cerebral white matter. Carmofur must be discontinued immediately if any psychomotor symptoms develop.

Effects of selected repeated intravitreal chemotherapeutic agents

The toxic effects of repeated intravitreal injections of selected chemotherapeutic agents were studied in female albino rabbits. Three groups of eyes participated in each therapeutic regimen. Agents studied were doxorubicin (dox), 3 and 5 micrograms; 5-fluorouracil (5-FU), 0.375 and 1.0 mg; bleomycin (bleo), 15 micrograms; thiotepa (thio), 12 micrograms; etoposide (VP-16), 150 micrograms; and methotrexate (MTX), 600 mic. Toxicity was evaluated using electroretinography (ERG) in 66% and histopathology in 100% of eyes 5 weeks following the initial injection and at least 2 weeks after the final injection of each series. Eyes receiving 2 doses of dox 3 micrograms showed no toxicity. Eyes receiving 3 or more doses of dox 3 micrograms and those treated with 2 or more doses of dox 5 demonstrated toxicity proportional to the number of doses received. Eyes treated with 5-FU 0.375 or 1.0 mg showed no toxic reaction. Successive intravitreal injections of 5-FU, 0.375 mg and dox 5 micrograms, and 5-FU, dox, and bleo produced no toxicity. Eyes treated with successive intravitreal injections of 5-FU, dox, bleo, and thio displayed decreased ERG response. The addition of VP-16 and MTX resulted in further loss of ERG response and more severe histologic retinal changes.