5-Fluorouracil-induced acute leukoencephalopathy: Case report and literature review

Toxic leukoencephalopathy (TL) refers to damage to the brain white matter following exposure to toxic agents. Multiple agents are incriminated in this condition, including chemotherapy drugs. 5-Fluorouracil, widely used in oncology, is responsible for neurotoxicity in less than 5% of cases. We report the case of a 54-year-old male patient who presented with neurological symptoms following 5-FU-based chemotherapy for gastric adenocarcinoma, and whose MRI scan revealed signs suggestive of toxic leukoencephalopathy. We also report on the evolution of the abnormalities described on his MRI after 1 year.

Chemotherapy-Induced Leukoencephalopathy Revealed by Seizure and Alteration of the Mental Status

Leukoencephalopathy is progressive demyelination of the white matter, induced by a variety of factors. Among the causes of leukoencephalopathy, chemotherapy is an uncommon cause that generates potentially reversible lesions. The clinical presentation is classically made of alterations in mental status, hallucinations, hypertension, seizures, and acute visual changes. Imaging plays an important role in the diagnosis of this entity, especially by conventional and diffusion-weighted magnetic resonance imaging which enables an accurate diagnosis by identifying symmetric white matter lesions, especially in the parietal and occipital lobes. Herein, we report a 54-year-old female patient, newly diagnosed with non-metastatic moderately differentiated adenocarcinoma of the cecum. The patient received her first cancer chemotherapy (5-fluorouracil at 300 mg/m²). Five days later she was admitted to the intensive care unit for confusion following two generalized seizures. Conventional and diffusion-weighted magnetic resonance imaging was performed and showed diffuse white matter lesions of the parietal and occipital lobes. A diagnosis of 5-fluorouracil-induced leukoencephalopathy was established. The diagnosis of leukoencephalopathy should be considered in patients receiving cancer chemotherapy with alterations in mental status and seizures.

Precision Oncology by Point-of-Care Therapeutic Drug Monitoring and Dosage Adjustment of Conventional Cytotoxic Chemotherapies: A Perspective

Therapeutic drug monitoring (TDM) of conventional cytotoxic chemotherapies is strongly supported yet poorly implemented in daily practice in hospitals. Analytical methods for the quantification of cytotoxic drugs are instead widely presented in the scientific literature, while the use of these therapeutics is expected to keep going for longer. There are two main issues hindering the implementation of TDM: turnaround time, which is incompatible with the dosage profiles of these drugs, and exposure surrogate marker, namely total area under the curve (AUC). Therefore, this perspective article aims to define the adjustment needed from current to efficient TDM practice for cytotoxics, namely point-of-care (POC) TDM. For real-time dose adjustment, which is required for chemotherapies, such POC TDM is only achievable with analytical methods that match the sensitivity and selectivity of current methods, such as chromatography, as well as model-informed precision dosing platforms to assist the oncologist with dose fine-tuning based on quantification results and targeted intervals.

Diagnosis and management of 5-fluorouracil (5-FU)-induced acute leukoencephalopathy: lessons learnt from a single-Centre case series

Background

The administration of 5-fluorouracil (5FU) in the treatment of gastrointestinal (GI) malignancies is associated with common side effects such as mucositis, diarrhoea, and myelosuppression, which are easily managed with supportive measures and dose adjustments. Cardiotoxicity and neurotoxicity are rare but reversible side effects of 5-FU and are treated with withdrawal of the drug and conservative measures. The presenting symptoms of 5-FU-induced leukoencephalopathy are often confusing and pose a diagnostic dilemma in routine clinical practice.

Methods

We report a series of five patients with GI malignancies who developed 5-FU-induced leukoencephalopathy.

Results

All (n = 5) had Naranjo scores of 6–7, predictive of 5-FU-related adverse effects, with clinical and radiological findings suggestive of 5-FU-induced encephalopathy as described in prior literature. The median time to onset of symptoms from initiation of 5FU was 3 days (range: 2–4 days). All patients improved after conservative management with complete neurological recovery.

Conclusion

Prompt recognition of this rare yet severe adverse effect of 5-FU-based chemotherapy aids early withdrawal of the offending agent (5-FU) and timely initiation of supportive measures and helps plan alternative oncological interventions.

5-Fluorouracil Neurotoxicity in the Absence of Dihydropyrimidine Dehydrogenase Deficiency Case Report

5 fluorouracil (5-FU)-related neurotoxicity is a rare and severe complication of 5-FU administration. Dihydropyrimidine dehydrogenase (DPD) deficiency is associated with an increased risk of serious adverse reactions due to its role in 5-FU metabolism. We report a case of acute reversible neurotoxicity with global areas of diffusion restriction in a patient with colorectal adenocarcinoma being treated with leucovorin calcium, 5-fluorouracil, and oxaliplatin (FOLFOX) without DPD deficiency following uridine triacetate administration.

Leukoencephalopathy with transient splenial lesions related to 5-fluorouracil or capecitabine

BACKGROUND

5-Fluorouracil (5-FU) and its oral prodrug capecitabine have been rarely but consistently associated with acute central nervous system toxicity, including transient leukoencephalopathies involving the splenium of the corpus callosum.

METHODS

We performed a retrospective search in the French Pharmacovigilance database (FPDB) (January 1985-July 2020) for adult patients affected by solid cancers who developed acute toxic leukoencephalopathies with splenial lesions following treatment with 5-FU or capecitabine. A comprehensive review of the literature helped to circumstantiate our findings.

RESULTS

Our research in the FPDB identified six patients who, within 3 days from their first cycle of 5-FU or capecitabine, developed acute neurological symptoms, including gait ataxia (n = 4), dysarthria (n = 3), dysmetria (n = 2), headache (n = 2), and confusion (n = 2). Brain magnetic resonance imaging (MRI) showed T2/FLAIR (fluid-attenuated inversion recovery) hyperintensities in the corpus callosum, with diffusion restriction and no contrast enhancement, generally accompanied by additional alterations in the bilateral supratentorial white matter (n = 5). All patients discontinued the agent supposedly responsible for the toxicity and experienced full recovery after a median of 8.5 days from symptom onset. Control MRI showed a progressive normalization of acute MRI abnormalities. Literature review identified 26 cases with similar clinical and paraclinical characteristics. A single patient from the literature resumed 5-FU at a lower dose, with no recurrent toxicity.

CONCLUSIONS

5-FU and capecitabine might be responsible for acute leukoencephalopathies with transient splenial lesions that are generally reversible upon drug discontinuation. Resuming the agent responsible for toxicity might be feasible in selected cases, after having excluded dihydropyrimidine dehydrogenase deficiency, if expected benefits outweigh the risks.

An imaging-based review of systemic therapies and associated toxicities in metastatic pancreatic cancer as per the 2018 ASCO guidelines: what every radiologist should know

OBJECTIVE

To provide an overview of what radiologists should know about systemic agents utilized in the modern treatment of metastatic pancreatic cancer and their associated toxicities.

RESULTS

The clinical landscape of metastatic pancreatic cancer has significantly evolved in recent years, with the advent of new first- and second-line systemic therapies. As these systemic treatment options continue to expand, knowledge of their clinically relevant features is becoming critical for radiologists. While the issues of surgical resectability and tumor response evaluation of advanced stages of pancreatic cancer have been thoroughly discussed in the radiology literature, the diagnostic importance of systemic therapies has tended to be less well appreciated. In this review, we provide a primer for radiologists outlining the radiologically pertinent features of modern systemic therapies used in the treatment of metastatic pancreatic ductal adenocarcinoma. These systemic agents are discussed from the standpoint of the newly updated 2018 ( https://doi.org/10.1007/s00261-019-01954-z ) guidelines for the treatment of metastatic pancreatic cancer from the American Society of Clinical Oncology (ASCO). Understanding the radiology relevance of these modern therapeutic agents is critical, especially with regard to treatment response and toxicity assessment.

CONCLUSION

Knowledge of the modern systemic therapies utilized in the treatment of metastatic pancreatic cancer and their associated toxicity profiles is critical in diagnostic imaging interpretation.

Changes in brain white matter integrity after systemic treatment for breast cancer: a prospective longitudinal study

An increasing number of studies suggest chemotherapy for breast cancer may be neurotoxic. Cross-sectional MRI diffusion tensor imaging (DTI) studies suggest a vulnerability of brain white matter to various chemotherapeutic regimens. Up till now, this was confirmed in one prospective DTI study: Deprez et al. (2012) showed a widespread decline in fractional anisotropy (FA) of breast cancer patients after chemotherapy consisting of 5-fluorouracil (5-FU), epirubicin and cyclophosphamide (FEC) +/- taxanes +/- endocrine treatment. Our aim was to evaluate whether similar detrimental effects on white matter integrity would be observed with the currently widely prescribed anthracycline-based chemotherapy for breast cancer (predominantly doxorubicin and cyclophosphamide +/- taxanes +/- endocrine treatment (=BC + SYST; n = 26) compared to no systemic treatment (BC; n = 23) and no-cancer controls (NC; n = 30). Assessment took place before and six months after chemotherapy, and matched intervals for the unexposed groups. DTI data were analyzed using voxel-based tract-based spatial statistics and region of interest (ROI) analysis. Voxel-based analysis did not show an effect of chemotherapy +/- endocrine treatment on white matter integrity. ROI analysis however indicated subtle detrimental effects of chemotherapy +/- endocrine treatment by showing a larger decline in WM integrity in the superior longitudinal fasciculus and corticospinal tract in BC + SYST than BC. Indications for relatively mild neurotoxicity in our study might be explained by patient characteristics and specific aspects of data analysis. The omission of 5-FU in current treatment regimens or the administration of doxorubicin instead of epirubicin is also discussed as an explanation for the observed effects.

[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.

5-FU-induced leukoencephalopathy with reversible lesion of splenium of corpus callosum in a patient with colorectal cancer

5-Fluorouracil (5-FU), a commonly used antimetabolite and antineoplastic agent, has been approved for treatment of various cancers. Neurotoxicities are considered extremely rare side effects of 5-FU. We present a case of 5-FU-induced encephalopathy with diffusion-restricted reversible lesion of the splenium of the corpus callosum in a patient with colorectal cancer. The patient presented with confusion, dysarthria and agitation after 5-FU infusion. The prognosis of this toxic effects of 5-FU is usually good if recognised and treated in time. Emergency physicians, general practitioners and oncologists should be aware of this rare side effects of 5-FU chemotherapy and its diagnosis and treatment.

MRI in Chemotherapy induced Leukoencephalopathy: Report of Two Cases and Radiologist's Perspective

Leukoencephalopathy is a progressive white matter disease primarily caused due to myelin damage by a variety of factors. Chemotherapy for oncological treatment is an uncommon but important cause of potentially reversible leukoencephalopathy. In current radiological setting, conventional and diffusion weighted MRI play a significant role in early and accurate detection of this entity. We are hereby presenting MRI evaluation of two cases of methotrexate and 5-fluorouracil induced toxic leukoencephalopathy.

Recovery correction technique for NMR spectroscopy of perchloric acid extracts using DL-valine-2,3-d2: validation and application to 5-fluorouracil-induced brain damage

PURPOSE

We explored a recovery correction technique that can correct metabolite loss during perchloric acid (PCA) extraction and minimize inter-assay variance in quantitative (1)H nuclear magnetic resonance (NMR) spectroscopy of the brain and evaluated its efficacy in 5-fluorouracil (5-FU)- and saline-administered rats.

METHODS

We measured the recovery of creatine and dl-valine-2,3-d2 from PCA extract containing both compounds (0.5 to 8 mM). We intravenously administered either 5-FU for 4 days (total, 100 mg/kg body weight) or saline into 2 groups of 11 rats each. We subsequently performed PCA extraction of the whole brain on Day 9, externally adding 7 µmol of dl-valine-2,3-d2. We estimated metabolite concentrations using an NMR spectrometer with recovery correction, correcting metabolite concentrations based on the recovery factor of dl-valine-2,3-d2. For each metabolite concentration, we calculated the coefficient of variation (CEV) and compared differences between the 2 groups using unpaired t-test.

RESULTS

Equivalent recoveries of dl-valine-2,3-d2 (89.4 ± 3.9%) and creatine (89.7 ± 3.9%) in the PCA extract of the mixed solution indicated the suitability of dl-valine-2,3-d2 as an internal reference. In the rat study, recovery of dl-valine-2,3-d2 was 90.6 ± 9.2%. Nine major metabolite concentrations adjusted by recovery of dl-valine-2,3-d2 in saline-administered rats were comparable to data in the literature. CEVs of these metabolites were reduced from 10 to 17% before to 7 to 16% after correction. The significance of differences in alanine and taurine between the 5-FU- and saline-administered groups was determined only after recovery correction (0.75 ± 0.12 versus 0.86 ± 0.07 for alanine; 5.17 ± 0.59 versus 5.66 ± 0.42 for taurine [µmol/g brain tissue]; P < 0.05).

CONCLUSION

A new recovery correction technique corrected metabolite loss during PCA extraction, minimized inter-assay variance in quantitative (1)H NMR spectroscopy of brain tissue, and effectively detected inter-group differences in concentrations of brain metabolites between 5-FU- and saline-administered rats.

The effect of systemic chemotherapy on neurogenesis, plasticity and memory

Chemotherapy has been enormously successful in treating many forms of cancer and improving patient survival rates. With the increasing numbers of survivors, a number of cognitive side effects have become apparent. These have been called "chemobrain" or "chemofog" among patient groups, who describe the symptoms as a decline in memory, concentration and executive functions. Changes which, although subtle, can cause significant distress among patients and prevent a return to the quality of life experienced before treatment. This cognitive side effect of chemotherapy was not anticipated as it had been assumed that chemotherapy agents, administered systematically, could not cross the blood-brain barrier and that the brain was therefore protected from their action. It is now realised that low concentrations of many chemotherapy agents cross the blood-brain barrier and even those that are completely prevented from doing so, can induce the production of inflammatory cytokines in peripheral tissues which in turn can cross the blood-brain barrier and impact on the brain. A large number of patient studies have shown that cognitive decline is found in a proportion of patients treated with a variety of chemotherapy agents for different types of cancer. The deficits experienced by these patients can last for up to several years and have a deleterious effect on educational attainment and ability to return to work. Imaging studies of patients after systemic chemotherapy show that this treatment produces structural and functional changes in the brain some of which seem to persist even when the cognitive deficits have ceased. This suggests that, with time, brain plasticity may be able to compensate for the deleterious effects of chemotherapy treatment. A number of mechanisms have been suggested for the changes in brain structure and function found after chemotherapy. These include both central and peripheral inflammatory changes, demyelination of white matter tracts, a reduction in stem cell proliferation in both the hippocampal neurogenic region and by oligodendrocyte precursors as well as changes in hormonal or growth factor levels. A number of possible treatments have been suggested which range from pharmacological interventions to cognitive behavioural therapies. Some of these have only been tested in animal models while others have produced varying degrees of improvement in patient populations. Currently, there is no recognised treatment and a greater understanding of the causes of the cognitive decline experienced after chemotherapy will be key to finding ways of preventing or treating the effects of chemobrain.

Longitudinal assessment of chemotherapy-induced structural changes in cerebral white matter and its correlation with impaired cognitive functioning

PURPOSE

To uncover the neural substrate of cognitive impairment related to adjuvant chemotherapy, we studied cerebral white matter (WM) integrity before and after chemotherapy by using magnetic resonance diffusion tensor imaging (DTI) in combination with detailed cognitive assessment.

PATIENTS AND METHODS

Thirty-four young premenopausal women with early-stage breast cancer who were exposed to chemotherapy underwent neuropsychologic testing and DTI before the start of chemotherapy (t1) and 3 to 4 months after treatment (t2). Sixteen patients not exposed to chemotherapy and 19 age-matched healthy controls underwent the same assessment at matched intervals. In all groups, we used paired t tests to study changes in neuropsychologic test scores and whole-brain voxel-based paired t tests to study changes in WM fractional anisotropy (FA; a DTI measure that reflects WM tissue organization), with depression scores and intelligence quotient as included covariates. We correlated changes of neuropsychologic test scores with the mean change of FA for regions that survived the paired t tests in patients treated with chemotherapy.

RESULTS

In contrast to controls, the chemotherapy-treated group performed significantly worse on attention tests, psychomotor speed, and memory at t2 compared with t1 (P < .05). In the chemotherapy-treated group, we found significant decreases of FA in frontal, parietal, and occipital WM tracts after treatment (familywise error P < .05), whereas for both control groups, FA values were the same between t1 and t2. Furthermore, performance changes in attention and verbal memory correlated with mean regional FA changes in chemotherapy-treated patients (P < .05).

CONCLUSION

We report evidence of longitudinal changes in cognitive functioning and cerebral WM integrity after chemotherapy as well as an association between both.