Neuroprotective effect of reduced glutathione on cisplatin-based chemotherapy in advanced gastric cancer: a randomized double-blind placebo-controlled trial

Advising patients on the use of non-herbal nutritional supplements during cancer therapy: a need for doctor-patient communication

CONTEXT

Many cancer patients are using non-herbal nutritional supplements (NHNS), often without informing their oncologists.

OBJECTIVES

To review the literature and summarize the beneficial effects and safety of NHNS in the prevention and reduction of treatment-related symptoms.

METHODS

Databases were searched for randomized, controlled clinical trials (Jadad score ≥ 2) using AltHealthWatch, Cochrane Database of Systematic Reviews, Embase, MEDLINE, Memorial Sloan-Kettering Integrative Medicine Service Database, Natural Standard Database, and PubMed. The key words searched were the following: alternative and/or complementary medicine, nutritional and/or dietary supplements, quality of life, symptoms and/or side effects, specific toxicities (e.g., neuropathy, mucositis), and specific supplements (e.g., vitamin E, glutamine, etc.).

RESULTS

A number of NHNS products were found to be effective. The incidence and severity of peripheral sensory neuropathy associated with taxane-agents such as paclitaxel can be reduced with vitamin E, glutamine, and acetyl-L-carnitine. Vitamin E and glutamine also have been shown to reduce oral mucositis resulting from radiation and chemotherapy, and glutamine and probiotics can reduce chemotherapy-induced diarrhea.

CONCLUSION

There is a need to develop an open and nonjudgmental dialogue between oncologists and cancer patients, addressing the needs of the patient while dealing with issues related to the efficacy and safety of these products. Referral of patients to an integrative medicine consultant may help achieve these goals, providing both parties with the option of reaching an informed and respectful decision about treatment.

Can medical herbs stimulate regeneration or neuroprotection and treat neuropathic pain in chemotherapy-induced peripheral neuropathy?

Chemotherapy-induced neuropathy (CIPN) has a relevant impact on the quality of life of cancer patients. There are no curative conventional treatments, so further options have to be investigated. We conducted a systematic review in English and Chinese language databases to illuminate the role of medical herbs. 26 relevant studies on 5 single herbs, one extract, one receptor-agonist, and 8 combinations of herbs were identified focusing on the single herbs Acorus calamus rhizoma, Cannabis sativa fructus, Chamomilla matricaria, Ginkgo biloba, Salvia officinalis, Sweet bee venom, Fritillaria cirrhosae bulbus, and the herbal combinations Bu Yang Huan Wu, modified Bu Yang Huan Wu plus Liuwei Di Huang, modified Chai Hu Long Gu Mu Li Wan, Geranii herba plus Aconiti lateralis praeparata radix , Niu Che Sen Qi Wan (Goshajinkigan), Gui Zhi Jia Shu Fu Tang (Keishikajutsubuto), Huang Qi Wu Wu Tang (Ogikeishigomotsuto), and Shao Yao Gan Cao Tang (Shakuyakukanzoto). The knowledge of mechanism of action is still limited, the quality of clinical trials needs further improvement, and studies have not yielded enough evidence to establish a standard practice, but a lot of promising substances have been identified. While CIPN has multiple mechanisms of neuronal degeneration, a combination of herbs or substances might deal with multiple targets for the aim of neuroprotection or neuroregeneration in CIPN.

Chemotherapy-Induced Peripheral Neuropathy in Pediatric Cancer Patients

Chemotherapy-induced peripheral neuropathies (CIPNs) are an increasingly common neuropathic and pain syndrome in adult and pediatric cancer patients and survivors [1-69]. However, symptoms associated with CIPNs are often undiagnosed, under-assessed, and communications problems between clinicians, family members, and patients have been observed [70-73]. Less is known about the prevalence and impact of CIPNs on pediatric cancer populations [70-71]. This article aims to provide a brief understanding of CIPNs in pediatric populations, and to review the evidence for both its prevention and treatment.

Nutraceuticals and chemotherapy induced peripheral neuropathy (CIPN): a systematic review

Chemotherapy induced peripheral neuropathy [CIPN] is a common significant and debilitating side effect resulting from the administration of neurotoxic chemotherapeutic agents. These pharmaco-chemotherapeutics can include taxanes, vinca alkaloids and others. Moderate to severe CIPN significantly decreases the quality of life and physical abilities of cancer patients and current pharmacotherapy for CIPN e.g. Amifostine and antidepressants have had limited efficacy and may themselves induce adverse side effects. To determine the potential use of nutraceuticals i.e. vitamin E, acetyl-L-carnitine, glutamine, glutathione, vitamin B6, omega-3 fatty acids, magnesium, calcium, alpha lipoic acid and n-acetyl cysteine as adjuvants in cancer treatments a systematic literature review was conducted. Revised clinical studies comprised of randomized clinical trials that investigated the anti-CIPN effect of nutraceuticals as the adjuvant intervention in patients administered chemotherapy. Twenty-four studies were assessed on methodological quality and limitations identified. Studies were mixed in their recommendations for nutraceuticals. Currently no agent has shown solid beneficial evidence to be recommended for the treatment or prophylaxis of CIPN. The standard of care for CIPN includes dose reduction and/or discontinuation of chemotherapy treatment. The management of CIPN remains an important challenge and future studies are warranted before recommendations for the use of supplements can be made.

Chemotherapy-induced peripheral neuropathy. Part II. Prevention

The incidence of chemotherapy-induced peripheral neuropathy (CIPN) in the population of cancer patients is estimated at 3-7% in cytostatic monotherapy and as high as 38% in the case of polytherapy. While testing drugs that may reduce the damage to the peripheral nervous system, particular attention should be paid to their protective action against the severe and painful complication in the patient. Another aspect, perhaps a more important one, is the confidence that application of preventive drugs will not exert a significant impact on progression of the neoplastic disease or the effectiveness of the causal treatment. Many drugs have been tested for prevention of CIPN; however, none of them have thus far been irrefutably proven to possess preventive properties. No guidelines on chemotherapy-induced peripheral neuropathy preventive action have been established, either. This article is an attempt to present reports from the available literature about the possibilities of prevention of CIPN.

Effects of oral glutathione supplementation on systemic oxidative stress biomarkers in human volunteers

BACKGROUND

The tripeptide glutathione (GSH) is the most abundant free radical scavenger synthesized endogenously in humans. Increasing mechanistic, clinical, and epidemiological evidence demonstrates that GSH status is significant in acute and chronic diseases. Despite ease of delivery, little controlled clinical research data exist evaluating the effects of oral GSH supplementation.

OBJECTIVES

The study objectives were to determine the effect of oral GSH supplementation on biomarkers of systemic oxidative stress in human volunteers.

DESIGN

This was a randomized, double-blind, placebo-controlled clinical trial.

SETTING/LOCATION

The study was conducted at Bastyr University Research Institute, Kenmore, WA and the Bastyr Center for Natural Health, Seattle, WA.

SUBJECTS

Forty (40) adult volunteers without acute or chronic disease participated in this study.

INTERVENTION

Oral GSH supplementation (500 mg twice daily) was given to the volunteers for 4 weeks.

OUTCOME MEASURES

Primary outcome measures included change in creatinine-standardized, urinary F2-isoprostanes (F2-isoP) and urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG). Changes in erythrocyte GSH concentrations, including total reduced glutathione (GSH), oxidized glutathione (GSSG), and their ratio (GSH:GSSG) were also measured by tandem liquid chromatography/mass spectrometry. Analysis of variance was used to evaluate differences between groups.

RESULTS

There were no differences in oxidative stress biomarkers between treatment groups at baseline. Thirty-nine (39) participants completed the study per protocol. Changes in creatinine standardized F2-isoP (ng/mg creatinine) (0.0±0.1 versus 0.0±0.1, p=0.38) and 8-OHdG (μg/g creatinine) (-0.2±3.3 versus 1.0±3.2, p=0.27) were nonsignificant between groups at week 4. Total reduced, oxidized, and ratio measures of GSH status were also unchanged.

CONCLUSIONS

No significant changes were observed in biomarkers of oxidative stress, including glutathione status, in this clinical trial of oral glutathione supplementation in healthy adults.

Systematic review: generating evidence-based guidelines on the concurrent use of dietary antioxidants and chemotherapy or radiotherapy

The risk-benefit ratio for concurrent use of dietary antioxidants with chemotherapy or radiation therapy is a controversial topic. In this review, the medical literature on concurrent antioxidant use with chemotherapy or radiotherapy was assessed and further steps for generating evidence-based guidelines are suggested. The clinical cancer research community should cooperate and focus new studies on the use of a specific combination of antioxidant and chemotherapy or radiotherapy, and determine optimal doses for a specific cancer setting. Mechanistic studies on the interaction between antioxidants and conventional cancer therapy could lead to novel biomarkers for assessing dose adequacy.

The use of vitamin E for the prevention of chemotherapy-induced peripheral neuropathy: results of a randomized phase III clinical trial

BACKGROUND

Chemotherapy-induced peripheral neuropathy (CIPN) continues to be a substantial problem for many cancer patients. Pursuant to promising appearing pilot data, the current study evaluated the use of vitamin E for the prevention of CIPN.

METHODS

A phase III, randomized, double-blind, placebo-controlled study was conducted in patients undergoing therapy with neurotoxic chemotherapy, utilizing twice daily dosing of vitamin E (400 mg)/placebo. The primary endpoint was the incidence of grade 2+ sensory neuropathy (SN) toxicity (CTCAE v 3.0) in each treatment arm, analyzed by chi-square testing. Planned sample size was 100 patients per arm to provide 80% power to detect a difference in incidence of grade 2+ SN toxicity from 25% in the placebo group to 10% in the vitamin E group.

RESULTS

Two-hundred seven patients were enrolled between December 1, 2006 and December 14, 2007, producing 189 evaluable cases for analysis. Cytotoxic agents included taxanes (109), cisplatin (8), carboplatin (2), oxaliplatin (50), or combination (20). There was no difference in the incidence of grade 2+ SN between the two arms (34%-vitamin E, 29%-placebo; P = 0.43). There were no significant differences between treatment arms for time to onset of neuropathy (P = 0.58), for chemotherapy dose reductions due to neuropathy (P = 0.21), or for secondary endpoints derived from patient-reported neuropathy symptom assessments. The treatment was well tolerated overall.

CONCLUSIONS

Vitamin E did not appear to reduce the incidence of sensory neuropathy in the studied group of patients receiving neurotoxic chemotherapy.

Objective evaluation of the alleviating effects of Goshajinkigan on peripheral neuropathy induced by paclitaxel/carboplatin therapy: A multicenter collaborative study

Paclitaxel/carboplatin chemotherapy for cancer (TC therapy) exhibits neurotoxicity and causes peripheral neuropathy at a high frequency, which is difficult to cope with. In this study, we investigated the efficacy of Goshajinkigan, a traditional Japanese herbal medicine, for TC therapy-induced peripheral neuropathy. The subjects included in our study were patients with ovarian or endometrial cancer who underwent TC therapy and developed peripheral neuropathy. The patients were randomly divided into Group A, comprising of 14 patients (vitamin B12 treatment), and Group B, comprising of 15 patients (vitamin B12 + Goshajinkigan treatment). The observation period was 6 weeks following treatment initiation, and the evaluation items were as follows: i) the current perception threshold (CPT value) of the peripheral nerve, ii) visual analogue scale for numbness, iii) National Cancer Institute Common Terminology Criteria for Adverse Events v3.0 grade of neurotoxicity, and iv) a questionnaire on the subjective symptoms of peripheral neuropathy (functional assessment of cancer therapy-taxane). These were compared between the groups and no significant differences were noted in any item. However, CTCAE grade 3 neurotoxicity developed in 2 patients (14.3%) after 6 weeks of administration in Group A, whereas no neurotoxicity was observed in Group B. When the change in the frequency of abnormal CPT ratio at 6 weeks of administration from that before treatment was compared between the groups, the frequency of abnormal value was significantly lower in Group B than in Group A (p<0.05). This suggests that Goshajinkigan inhibits the progression of peripheral neuropathy.

Anti-cancer effect of pharmacologic ascorbate and its interaction with supplementary parenteral glutathione in preclinical cancer models

Two popular complementary, alternative, and integrative medicine therapies, high-dose intravenous ascorbic acid (AA) and intravenous glutathione (GSH), are often coadministered to cancer patients with unclear efficacy and drug-drug interaction. In this study we provide the first survey evidence for clinical use of iv GSH with iv AA. To address questions of efficacy and drug-drug interaction, we tested 10 cancer cell lines with AA, GSH, and their combination. The results showed that pharmacologic AA induced cytotoxicity in all tested cancer cells, with IC(50) less than 4 mM, a concentration easily achievable in humans. GSH reduced cytotoxicity by 10-95% by attenuating AA-induced H(2)O(2) production. Treatment in mouse pancreatic cancer xenografts showed that intraperitoneal AA at 4 g/kg daily reduced tumor volume by 42%. Addition of intraperitoneal GSH inhibited the AA-induced tumor volume reduction. Although all treatments (AA, GSH, and AA+GSH) improved survival rate, AA+GSH inhibited the cytotoxic effect of AA alone and failed to provide further survival benefit. These data confirm the pro-oxidative anti-cancer mechanism of pharmacologic AA and suggest that AA and GSH administered together provide no additional benefit compared with AA alone. There is an antagonism between ascorbate and glutathione in treating cancer, and therefore iv AA and iv GSH should not be coadministered to cancer patients on the same day.

Chemotherapy-induced neuropathy

OPINION STATEMENT

Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of the most severe and unpredictable side effects of modern anticancer treatment. In recent years, a clear understanding of the importance of an integrated approach to CIPN has become evident, and efforts are increasing to better characterize its features and to identify more accurate methods to report and grade its occurrence. The clinically relevant impact of CIPN on cancer patients has been known for a long time, but knowledge of its pathogenetic aspects is still very limited. This incomplete knowledge is one of the major limitations in identifying targets for evidence-based neuroprotective strategies. Nevertheless, several studies have been devoted to the prevention or at least the effective treatment of symptoms secondary to peripheral nerve damage and to the early identification of patients at high risk of developing severe CIPN. Unfortunately, none of these studies has been successful and the optimal management of CIPN patients is still an unmet clinical need. Therefore, the modification of chemotherapy is currently the only available approach to limit the severity of neuropathy in the vast majority of patients. The indications for treatment modification are not universally accepted and they can differ among the various drugs. Generally, treatment modification should be considered as soon as symptoms and signs impair the daily life activities of the patient, but the possibility of a delayed worsening of CIPN after treatment withdrawal ("coasting") should always be considered, and delay of modification decisions should be avoided.

Chemotherapy-induced peripheral neurotoxicity in the era of pharmacogenomics

Development of advanced and high-throughput methods to study variability in human genes means we can now use pharmacogenomic analysis not only to predict response to treatment but also to assess the toxic action of drugs on normal cells (so-called toxicogenomics). This technological progress could enable us to identify individuals at high and low risk for a given side-effect. Pharmacogenomics could be very useful for stratification of cancer patients at risk of developing chemotherapy-induced peripheral neurotoxicity, one of the most severe and potentially permanent non-haematological side-effects of modern chemotherapeutic agents. However, study data reported so far are inconsistent, which suggests that methodological improvement is needed in clinical trials to obtain reliable results in this clinically relevant area.

Neurotoxicity caused by the treatment with platinum analogues

Platinum agents (cisplatin, carboplatin, and oxaliplatin) are a class of chemotherapy agents that have a broad spectrum of activity against several solid tumors. Toxicity to the peripheral nervous system is the major dose-limiting toxicity of at least some of the platinum drugs of clinical interest. Among the platinum compounds in clinical use, cisplatin is the most neurotoxic, inducing mainly sensory neuropathy of the upper and lower extremities. Carboplatin is generally considered to be less neurotoxic than cisplatin, but it is associated with a higher risk of neurological dysfunction if administered at high dose or in combination with agents considered to be neurotoxic. Oxaliplatin induces two types of peripheral neuropathy, acute and chronic. The incidence of oxaliplatin-induced neuropathy is related to various risk factors such as treatment schedule, cumulative dose, and time of infusion. To date, several neuroprotective agents including thiol compounds, vitamin E, various anticonvulsants, calcium-magnesium infusions, and other nonpharmacological strategies have been tested for their ability to prevent platinum-induced neurotoxicity with controversial results. Further studies on the prevention and treatment of neurotoxicity of platinum analogues are warranted.

Cardioprotective interventions for cancer patients receiving anthracyclines

BACKGROUND

Anthracyclines are among the most effective chemotherapeutic agents in the treatment of numerous malignancies. Unfortunately, their use is limited by a dose-dependent cardiotoxicity. In an effort to prevent this cardiotoxicity, different cardioprotective agents have been studied.

OBJECTIVES

The objective of this review was to assess the efficacy of different cardioprotective agents in preventing heart damage in cancer patients treated with anthracyclines.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 10), MEDLINE (1966 to November 2010) and EMBASE (1980 to November 2010) databases. In addition, we handsearched reference lists, conference proceedings of the International Society of Paediatric Oncology (SIOP) and American Society of Clinical Oncology (ASCO) meetings (1998 to 2010) and ongoing trials registers.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which any cardioprotective agent was compared to no additional therapy or placebo in cancer patients (children and adults) receiving anthracyclines.

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection, risk of bias assessment and data extraction including adverse effects.

MAIN RESULTS

We identified RCTs for the eight cardioprotective agents N-acetylcysteine, phenethylamines, coenzyme Q10, a combination of vitamins E and C and N-acetylcysteine, L-carnitine, carvedilol, amifostine and dexrazoxane (mostly for adults with advanced breast cancer). All studies had methodological limitations and for the first seven agents there were too few studies to allow pooling of results. None of the individual studies showed a cardioprotective effect. The 10 included studies on dexrazoxane enrolled 1619 patients. The meta-analysis for dexrazoxane showed a statistically significant benefit in favour of dexrazoxane for the occurrence of heart failure (risk ratio (RR) 0.29, 95% CI 0.20 to 0.41). No evidence was found for a difference in response rate or survival between the dexrazoxane and control groups. The results for adverse effects were ambiguous. No significant difference in the occurrence of secondary malignancies was identified.

AUTHORS' CONCLUSIONS

No definitive conclusions can be made about the efficacy of cardioprotective agents for which pooling of results was impossible. Dexrazoxane prevents heart damage and no evidence for a difference in response rate or survival between the dexrazoxane and control groups was identified. The evidence available did not allow us to reach any definite conclusions about adverse effects. We conclude that if the risk of cardiac damage is expected to be high, it might be justified to use dexrazoxane in patients with cancer treated with anthracyclines. However, clinicians should weigh the cardioprotective effect of dexrazoxane against the possible risk of adverse effects for each individual patient.

Use of chemoprotectants in chemotherapy and radiation therapy: the challenges of selecting an appropriate agent

Chemoprotection refers to the protection from the toxicity of one chemical by the intervention of another. Conflicting preclinical and clinical reports make it difficult to either ignore or accept the use of chemoprotectants during cancer chemotherapy or radiotherapy. The selection of anticancer drugs depends on the type and stage of cancer development. However, very little attention has been paid to the selection of chemoprotectants. The answer to the use of chemoprotectants during cancer therapy lies in their appropriate selection in a case-specific and/or issue-specific manner. The need of the hour is to find better answers on the rationality of chemoprotectants selection during cancer therapy using cutting-edge science. In this commentary, we have presented few examples to justify our view-points.

Interventions for preventing neuropathy caused by cisplatin and related compounds

BACKGROUND

Cisplatin and several related antineoplastic agents used to treat many types of solid tumors are neurotoxic, and most patients completing a full course of cisplatin chemotherapy develop a clinically detectable sensory neuropathy. Effective neuroprotective therapies have been sought.

OBJECTIVES

To examine the efficacy of purported chemoprotective agents to prevent or limit the neurotoxicity of cisplatin and related agents.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Specialized Register (25 August 2010), the Cochrane Central Register of Controlled Trials (Issue 3, 2010 in The Cochrane Library), MEDLINE (January 1966 to August 2010), EMBASE (January 1980 to August 2010), LILACS (January 1982 to August 2010), CINAHL (January 1982 to August 2010) for randomized trials designed to evaluate neuroprotective agents used to prevent or limit neurotoxicity of cisplatin and related agents among human patients.

SELECTION CRITERIA

Quasi-randomized or randomized controlled trials whose participants received cisplatin (or related compounds) chemotherapy with or without a potential chemoprotectant (acetylcysteine, amifostine, ACTH, BNP7787, calcium and magnesium, diethyldithiocarbamate, glutathione, Org 2766, oxcarbazepine, or vitamin E) and were evaluated zero to six months after completing chemotherapy using quantitative sensory testing (primary) or other measures including nerve conduction studies or neurological impairment rating using validated scales (secondary).

DATA COLLECTION AND ANALYSIS

We identified 16 randomized trials involving five possible chemoprotective agents in the initial 2006 review. Each study was reviewed by two authors who extracted the data and reached consensus. The 2010 update identified 11 additional randomized trials consisting of nine possible chemoprotective agents, including three treatments (acetylcysteine, calcium and magnesium, and oxcarbazepine) not among those described in the 2006 review. The included trials in the updated review involved eight unrelated treatments and included many disparate measures of neuropathy, resulting in insufficient data for any one measure to combine the results in most instances.

MAIN RESULTS

One of four eligible amifostine trials (541 total participants in all four trials) used quantitative sensory testing and demonstrated a favorable outcome in terms of amifostine neuroprotection, but the vibration perception threshold result was based on data from only 14 participants receiving amifostine who completed the post-treatment evaluation and should be regarded with caution. Of the six eligible glutathione trials (354 participants), one used quantitative sensory testing but reported only qualitative analyses. Four eligible Org 2766 trials (311 participants) employed quantitative sensory testing reported disparate results; meta-analyses of three trials using comparable measures showed no significant vibration perception threshold neuroprotection. The remaining trial reported only descriptive analyses. The single eligible trials involving acetylcysteine (14 participants), diethyldithiocarbamate (195 participants), calcium and magnesium (33 participants), and oxcarbazepine (32 participants) and the two eligible trials involving vitamin E (57 participants) did not perform quantitative sensory testing. In all, data from 1,537 participants were included.

AUTHORS' CONCLUSIONS

At present, the data are insufficient to conclude that any of the purported chemoprotective agents (acetylcysteine, amifostine, calcium and magnesium, diethyldithiocarbamate, glutathione, Org 2766, oxycarbazepine, or Vitamin E) prevent or limit the neurotoxicity of platin drugs among human patients.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer currently ranks second in global cancer mortality. Most patients are either diagnosed at an advanced stage, or develop a relapse after surgery with curative intent. Apart from supportive care and palliative radiation to localized (e.g. bone) metastasis, systemic chemotherapy is the only treatment option available in this situation.

OBJECTIVES

To assess the efficacy of chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapy regimens in advanced gastric cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE up to March 2009, reference lists of studies, and contacted pharmaceutical companies and national and international experts.

SELECTION CRITERIA

Randomised controlled trials on systemic intravenous chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapies in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

Thirty five trials, with a total of 5726 patients, have been included in the meta-analysis of overall survival. The comparison of chemotherapy versus best supportive care consistently demonstrated a significant benefit in overall survival in favour of the group receiving chemotherapy (hazard ratios (HR) 0.37; 95% confidence intervals (CI) 0.24 to 0.55, 184 participants). The comparison of combination versus single-agent chemotherapy provides evidence for a survival benefit in favour of combination chemotherapy (HR 0.82; 95% CI 0.74 to 0.90, 1914 participants). The price of this benefit is increased toxicity as a result of combination chemotherapy. When comparing 5-FU/cisplatin-containing combination therapy regimens with versus without anthracyclines (HR 0.77; 95% CI 0.62 to 0.95, 501 participants) and 5-FU/anthracycline-containing combinations with versus without cisplatin (HR 0.82; 95% CI 0.73 to 0.92, 1147 participants) there was a significant survival benefit for regimens including 5-FU, anthracyclines and cisplatin. Both the comparison of irinotecan versus non-irinotecan (HR 0.86; 95% CI 0.73 to 1.02, 639 participants) and docetaxel versus non-docetaxel containing regimens (HR 0.93; 95% CI 0.75 to 1.15, 805 participants) show non-significant overall survival benefits in favour of the irinotecan and docetaxel-containing regimens.

AUTHORS' CONCLUSIONS

Chemotherapy significantly improves survival in comparison to best supportive care. In addition, combination chemotherapy improves survival compared to single-agent 5-FU. All patients should be tested for their HER-2 status and trastuzumab should be added to a standard fluoropyrimidine/cisplatin regimen in patients with HER-2 positive tumours. Two and three-drug regimens including 5-FU, cisplatin, with or without an anthracycline, as well as irinotecan or docetaxel-containing regimens are reasonable treatment options for HER-2 negative patients.

Administration of reduced glutathione in FOLFOX4 adjuvant treatment for colorectal cancer: effect on oxaliplatin pharmacokinetics, Pt-DNA adduct formation, and neurotoxicity

Oxaliplatin is a promising drug for cancer therapy and the oxaliplatin/5-fluorouracil/leucovorin (FOLFOX) regimen has become the standard adjuvant treatment for colorectal cancer. However, the oxaliplatin-induced neurotoxicity still represents a clinical problem leading to a discontinuation of the therapy. Many strategies have been proposed in order to manage the neurotoxicity, but their effect on antitumoral efficacy is still unclear. In this study, we investigated the effect of reduced glutathione administration on neurotoxicity, oxaliplatin pharmacokinetics, and platinum-DNA (Pt-DNA) adduct formation in patients affected by colorectal cancer treated with FOLFOX4 adjuvant regimen. Twenty-seven patients were randomized to receive GSH 1500 mg/m or saline solution before oxaliplatin infusion. Evaluation of neurotoxicity, pharmacokinetics of plasmatic total and ultrafiltered Pt, and determination of Pt-DNA adduct formation on white blood cells was performed during the 5th, 9th, and 12th cycles. At the end of all cycles of therapy, the patients in the GSH arm showed a statistically significant reduction of neurotoxicity (P=0.0037) compared with the placebo arm. There were no significant differences in the main pharmacokinetic parameters between the two arms except a lower area under the plasma concentration-time curve and a smaller apparent steady-state volume of distribution (Vss) when GSH was coadministered. This difference can be explained by the natural function of GSH in the detoxification of oxaliplatin and by its ability to remove the Pt bound to plasma proteins. The determination of Pt-DNA adduct formation shows no statistically significant differences between the two arms. In conclusion, this study indicates that coadministration of GSH is an effective strategy to reduce the oxaliplatin-induced neurotoxicity without impairing neither the pharmacokinetics of oxaliplatin, nor the Pt-DNA adduct formation.

Therapy of chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) is still a common and disabling side effect of many chemotherapy agents in use today. Unfortunately, neither prophylactic strategies nor symptomatic treatments have proven useful yet. This review will discuss the diagnosis and evaluation of neuropathy in cancer patients, as well as reviewing the various prophylactic and symptomatic treatments that have been proposed or tried. However, sufficient evidence is lacking to recommend any of these treatments to patients suffering with CIPN. Therefore, the best approach is to treat symptomatically, and to start with broad-spectrum analgesic medications such as non-steroidal anti-inflammatory drugs (NSAIDs). If NSAIDs fail, a reasonable second-line agent in properly selected patients may be an opioid. Unfortunately, even when effective in other types of neuropathic pain, anti-depressants and anticonvulsants have not yet proven effective for treating the symptoms of CIPN.

Impact of antioxidant supplementation on chemotherapeutic toxicity: a systematic review of the evidence from randomized controlled trials

Much debate has focused on whether antioxidants interfere with the efficacy of cancer chemotherapy. The objective of this study is to systematically review the randomized, controlled clinical trial evidence evaluating the effects of concurrent use of antioxidants with chemotherapy on toxic side effects. We performed a search of literature from 1966-October 2007 using MEDLINE, Cochrane, CinAhl, AMED, AltHealthWatch and EMBASE databases. Randomized, controlled clinical trials reporting antioxidant-based mitigation of chemotherapy toxicity were included in the final tally. Searches were performed following a standardized protocol for systematic reviews. Only 33 of 965 articles considered, including 2,446 subjects, met the inclusion criteria. Antioxidants evaluated were: glutathione (11), melatonin (7), vitamin A (1), an antioxidant mixture (2), N-acetylcysteine (2), vitamin E (5), selenium (2), L-carnitine (1), Co-Q10 (1) and ellagic acid (1). The majority (24) of the 33 studies included reported evidence of decreased toxicities from the concurrent use of antioxidants with chemotherapy. Nine studies reported no difference in toxicities between the 2 groups. Only 1 study (vitamin A) reported a significant increase in toxicity in the antioxidant group. Five studies reported the antioxidant group completed more full doses of chemotherapy or had less-dose reduction than control groups. Statistical power and poor study quality were concerns with some studies. This review provides the first systematically reviewed evidence that antioxidant supplementation during chemotherapy holds potential for reducing dose-limiting toxicities. However, well-designed studies evaluating larger populations of patients given specific antioxidants defined by dose and schedule relative to chemotherapy are warranted.

Chemotherapy-induced peripheral neuropathy: prevention and treatment strategies

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose limiting side effect of many commonly used chemotherapeutic agents, including platinum drugs, taxanes, epothilones and vinca alkaloids, and also newer agents such as bortezomib and lenolidamide. Symptom control studies have been conducted looking at ways to prevent or alleviate established CIPN. This manuscript provides a review of studies directed at both of these areas. New evidence strongly suggests that intravenous calcium and magnesium therapy can attenuate the development of oxaliplatin-induced CIPN, without reducing treatment response. Accumulating data suggest that vitamin E may also attenuate the development of CIPN, but more data regarding its efficacy and safety should be obtained prior to its general use in patients. Other agents that look promising in preliminary studies, but need substantiation, include glutamine, glutathione, N-acetylcysteine, oxcarbazepine, and xaliproden. Effective treatment of established CIPN, however, has yet to be found. Lastly, paclitaxel causes a unique acute pain syndrome which has been hypothesised to be caused by neurologic injury. No drugs, to date, have been proven to prevent this toxicity.

Chemotherapy-induced neuropathy

Neurotoxic side effects of cancer therapy are second in frequency to hematological toxicity. Unlike hematological side effects that can be treated with hematopoietic growth factors, neuropathies cannot be treated and protective treatment strategies have not been effective. For the neurologist, the diagnosis of a toxic neuropathy is primarily based on the case history, the clinical and electrophysiological findings, and knowledge of the pattern of neuropathy associated with specific agents. In most cases, toxic neuropathies are length-dependent, sensory, or sensorimotor neuropathies often associated with pain. The platinum compounds are unique in producing a sensory ganglionopathy. Neurotoxicity is usually dependent on cumulative dose. Severity of neuropathy increases with duration of treatment and progression stops once drug treatment is completed. The platinum compounds are an exception where sensory loss may progress for several months after cessation of treatment ("coasting"). As more effective multiple drug combinations are used, patients will be treated with several neurotoxic drugs. Synergistic neurotoxicity has not been extensively investigated. Pre-existent neuropathy may influence the development of a toxic neuropathy. Underlying inherited or inflammatory neuropathies may predispose patients to developing very severe toxic neuropathies. Other factors such as focal radiotherapy or intrathecal administration may enhance neurotoxicity. The neurologist managing the cancer patient who develops neuropathy must answer a series of important questions as follows: (1) Are the symptoms due to peripheral neuropathy? (2) Is the neuropathy due to the underlying disease or the treatment? (3) Should treatment be modified or stopped because of the neuropathy? (4) What is the best supportive care in terms of pain management or physical therapy for each patient? Prevention of toxic neuropathies is most important. In patients with neuropathy, restorative approaches have not been well established. Symptomatic and other management are necessary to maintain and improve quality of life.

Should supplemental antioxidant administration be avoided during chemotherapy and radiation therapy?

Despite nearly two decades of research investigating the use of dietary antioxidant supplementation during conventional chemotherapy and radiation therapy, controversy remains about the efficacy and safety of this complementary treatment. Several randomized clinical trials have demonstrated that the concurrent administration of antioxidants with chemotherapy or radiation therapy reduces treatment-related side effects. Some data indicate that antioxidants may protect tumor cells as well as healthy cells from oxidative damage generated by radiation therapy and some chemotherapeutic agents. However, other data suggest that antioxidants can protect normal tissues from chemotherapy- or radiation-induced damage without decreasing tumor control. We review some of the data regarding the putative benefits and potential risks of antioxidant supplementation concurrent with cytotoxic therapy. On the basis of our review of the published randomized clinical trials, we conclude that the use of supplemental antioxidants during chemotherapy and radiation therapy should be discouraged because of the possibility of tumor protection and reduced survival.

Putting evidence into practice: evidence-based interventions for chemotherapy-induced peripheral neuropathy

Chemotherapy-induced peripheral neuropathy (CIPN) continues to be a significant, debilitating symptom resulting from the administration of neurotoxic chemotherapy for the treatment of cancer. CIPN is an important consequence of cancer treatment because of its potential impact on physical functioning and quality of life. Oncology nurses play an important role in assessing, monitoring, and educating clients about CIPN. Despite investigations concerning pharmacologic and nonpharmacologic approaches to either preventing or minimizing the neurotoxicity resulting from certain chemotherapeutic agents, evidence to support the interventions is lacking. This article presents information concerning CIPN and summarizes the evidence for pharmacologic and nonpharmacologic approaches to the prevention and treatment of CIPN.

Phenoxodiol protects against Cisplatin induced neurite toxicity in a PC-12 cell model

BACKGROUND

Many commonly used chemotherapeutic agents, such as Cisplatin, are restricted in their potential anti-neoplastic effectiveness by their side effects, with one of the most problematic being induction of peripheral neuropathy. Although a number of different neurotrophic, neuroprotective or anti-oxidant treatments have been tried in order to prevent or treat the neuropathies, to date they have met with limited success. Phenoxodiol is a new chemotherapeutic agent that has anti-proliferative and apoptotic effects on a range of cancer cells. PC12 cells are a commonly used neuronal cell model for examination of neurite outgrowth. In this study we examined whether phenoxodiol could protect against Cisplatin induced neurite inhibition in PC12 cells as an indication of the potential to protect against neuropathy.

RESULTS

Using the PC12 neuronal cell line, concentrations of Cisplatin were chosen that induced moderate or strong neurite toxicity within 24 hrs but were not cytotoxic. The effect of Phenoxodiol on Cisplatin induced neurite toxicity was assessed by measurement of neurite outgrowth. Addition of phenoxodiol at 100 nM or 1 microM showed no cytotoxicity and blocked the Cisplatin induced neurite toxicity, while phenoxodiol at 10 microM was cytotoxic and enhanced neurite toxicity of Cisplatin. When Cisplatin was added for 24 hrs, then washed out and the cells allowed to recover for 48 hrs, neurite outgrowth was not restored and addition of phenoxodiol did not further promote recovery or restore the Cisplatin treated cells.

CONCLUSION

In addition to its potential as a chemotherapeutic agent Phenoxodiol may thus also have the potential to be used in conjunction with Cisplatin chemotherapy to prevent induction of neuropathy.

Adjuvant treatment of high-risk, radically resected gastric cancer patients with 5-fluorouracil, leucovorin, cisplatin, and epidoxorubicin in a randomized controlled trial

BACKGROUND

Promising findings obtained using a weekly regimen of 5-fluorouracil (5-FU), epidoxorubicin, leucovorin (LV), and cisplatin (PELFw) to treat locally advanced and metastatic gastric cancer prompted the Italian Group for the Study of Digestive Tract Cancer (GISCAD) to investigate the efficacy of this regimen as adjuvant treatment for high-risk radically resected gastric cancer patients.

METHODS

From January 1998 to January 2003, 400 gastric cancer patients at high risk for recurrence including patients with serosal invasion (stage pT3 N0) and/or lymph node metastasis (stage pT2 or pT3 N1, N2, or N3), were enrolled in a trial of adjuvant chemotherapies; 201 patients were randomly assigned to receive the PELFw regimen, consisting of eight weekly administrations of cisplatin (40 mg/m2), LV (250 mg/m2), epidoxorubicin (35 mg/m2), 5-FU (500 mg/m2), and glutathione (1.5 g/m2) with the support of filgrastim, and 196 patients were assigned to a regimen consisting of six monthly administrations of a 5-day course of 5-FU (375 mg/m2 daily) and LV (20 mg/m2 daily, 5-FU/LV). Disease-free and overall survival were estimated and compared between arms using hazard ratios (HRs) and Kaplan-Meier estimates. All statistical tests were two-sided.

RESULTS

The 5-year survival rates were 52% in the PELFw arm and 50% in the 5-FU/LV arm. Compared with the 5-FU/LV regimen, the PELFw regimen did not reduce the risk of death (HR = 0.95, 95% confidence interval [CI] = 0.70 to 1.29) or relapse (HR = 0.98, 95% CI = 0.75 to 1.29). Less than 10% of patients in either arm experienced a grade 3 or 4 toxic episode. Neutropenia (occurring more often in the PELFw arm) and diarrhea and mucositis (more prevalent in the 5-FU/LV arm) were the most common serious side effects. Nevertheless, only 19 patients (9.4%) completed the treatment in the PELFw arm and 85 (43%) patients completed the treatment in the 5-FU/LV arm.

CONCLUSIONS

Our study found no benefit from an intensive weekly chemotherapy in gastric cancer. The extent of toxicity experienced by the patients in the adjuvant setting suggests that, in gastric cancer, chemotherapy may be more safely administered preoperatively.

Neuroprotection during chemotherapy: a systematic review

The development of neurotoxicity during antineoplastic therapy is one of the most common reasons for termination or modification of cancer treatment. A number of different agents have been proposed to provide neuroprotection without affecting antitumor efficacy. This review provides an evidence-based summary of neuroprotective medicines, an overview of the literature relating to neuroprotection during cancer treatment and a Neurologist perspective risk assessment and management. Through a systematic review the authors identified 49 papers published to date that report human clinical trials involving potential neuroprotectants in adults. Case reports and series completed in a prospective fashion were also included. Sensory neuropathies were the most prevalent subtype in the literature, and most were at least partially reversible with or without neuroprotective treatment. The majority of study medications had minimal side effects, though 2 trials were prematurely terminated because of adverse patient outcomes. No study reported an effect on antitumor efficacy. Because of the variability in study design, cancer type, outcome measures, and clinical confirmation of neuropathy, meta-analysis could not be appropriately performed. We highlight risk factors and discuss neuropathy screening. Descriptive analysis is provided which reveals that many of the agents studied were likely to confer some at least some neuroprotective benefit.

Impact of antioxidant supplementation on chemotherapeutic efficacy: a systematic review of the evidence from randomized controlled trials

PURPOSE

Much debate has arisen about whether antioxidant supplementation alters the efficacy of cancer chemotherapy. Some have argued that antioxidants scavenge the reactive oxygen species integral to the activity of certain chemotherapy drugs, thereby diminishing treatment efficacy. Others suggest antioxidants may mitigate toxicity and thus allow for uninterrupted treatment schedules and a reduced need for lowering chemotherapy doses. The objective of this study is to systematically review the literature in order to compile results from randomized trials that evaluate concurrent use of antioxidants with chemotherapy.

DESIGN

MEDLINE, Cochrane, CinAhl, AMED, AltHealthWatch and EMBASE databases were searched. Only randomized, controlled clinical trials that reported survival and/or tumor response were included in the final tally. The literature searches were performed in duplicate following a standardized protocol. No meta-analysis was performed due to heterogeneity of tumor types and treatment protocols used in trials that met the inclusion criteria.

RESULTS

Of 845 articles considered, 19 trials met the inclusion criteria. Antioxidants evaluated were: glutathione (7), melatonin (4), vitamin A (2), an antioxidant mixture (2), vitamin C (1), N-acetylcysteine (1), vitamin E (1) and ellagic acid (1). Subjects of most studies had advanced or relapsed disease.

CONCLUSION

None of the trials reported evidence of significant decreases in efficacy from antioxidant supplementation during chemotherapy. Many of the studies indicated that antioxidant supplementation resulted in either increased survival times, increased tumor responses, or both, as well as fewer toxicities than controls; however, lack of adequate statistical power was a consistent limitation. Large, well-designed studies of antioxidant supplementation concurrent with chemotherapy are warranted.

Interventions for preventing neuropathy caused by cisplatin and related compounds

BACKGROUND

Cisplatin and several related antineoplastic agents used to treat many types of solid tumors are neurotoxic, and most patients completing a full course of cisplatin chemotherapy develop a clinically detectable sensory neuropathy. Effective neuroprotective therapies have been sought.

OBJECTIVES

To examine the efficacy of purported chemoprotective agents to prevent or limit the neurotoxicity of cisplatin and related agents among human patients.

SEARCH STRATEGY

We searched the Cochrane Neuromuscular Disease Group Register (January 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library, Issue 1 2005), MEDLINE from (January 1966 to March 2005), EMBASE (from January 1980 to March 2005), LILACS (from January 1982 to March 2005), CINAHL (from January 1982 to March 2005) for randomized trials designed to evaluate neuroprotective agents used to prevent or limit neurotoxicity of cisplatin and related agents among human patients.

SELECTION CRITERIA

Quasi-randomized or randomized controlled trials whose participants received cisplatin (or related compounds) chemotherapy with or without a potential neuroprotectant (amifostine, diethyldithiocarbamate, glutathione, Org 2766, or vitamin E) and were evaluated zero to six months after completing chemotherapy using quantitative sensory testing (primary) or other measures including nerve conduction studies or neurological impairment rating using validated scales (secondary).

DATA COLLECTION AND ANALYSIS

We identified 16 randomized trials involving five possible chemoprotective agents. Each study was reviewed by two authors who extracted the data and reached consensus. The included trials involved five unrelated treatments and included many disparate measures of neuropathy, resulting in insufficient data for any one measure to combine the results in most instances.

MAIN RESULTS

The one of five eligible amifostine trials (541 participants) using quantitative sensory testing demonstrated a favorable outcome in terms of amifostine neuroprotection, but the subclinical result was based on 14 participants receiving amifostine. Of the five eligible glutathione trials (327 participants), one used quantitative sensory testing but reported only qualitative analyses. Four eligible Org 2766 trials (311 participants) employed quantitative sensory testing reported disparate results; meta-analyses of three trials using comparable measures showed no significant vibration perception threshold neuroprotection. The remaining trial reported only descriptive analyses. The one eligible diethyldithiocarbamate trial (214 participants) and the one eligible vitamin E trial (27 participants) did not perform quantitative sensory testing.

AUTHORS' CONCLUSIONS

At present, the data are insufficient to conclude if any of the purported neuroprotective agents (amifostine, diethyldithiocarbamate, glutathione, Org 2766, or Vitamin E) prevent or limit the neurotoxicity of platin drugs among human patients.

Evidence of toxicity, oxidative stress, and neuronal insult in autism

According to the Autism Society of America, autism is now considered to be an epidemic. The increase in the rate of autism revealed by epidemiological studies and government reports implicates the importance of external or environmental factors that may be changing. This article discusses the evidence for the case that some children with autism may become autistic from neuronal cell death or brain damage sometime after birth as result of insult; and addresses the hypotheses that toxicity and oxidative stress may be a cause of neuronal insult in autism. The article first describes the Purkinje cell loss found in autism, Purkinje cell physiology and vulnerability, and the evidence for postnatal cell loss. Second, the article describes the increased brain volume in autism and how it may be related to the Purkinje cell loss. Third, the evidence for toxicity and oxidative stress is covered and the possible involvement of glutathione is discussed. Finally, the article discusses what may be happening over the course of development and the multiple factors that may interplay and make these children more vulnerable to toxicity, oxidative stress, and neuronal insult.

Protective effect of erythropoietin and its carbamylated derivative in experimental Cisplatin peripheral neurotoxicity

PURPOSE

Antineoplastic drugs, such as cisplatin (CDDP), are severely neurotoxic, causing disabling peripheral neuropathies with clinical signs known as chemotherapy-induced peripheral neurotoxicity. Cotreatment with neuroprotective agents and CDDP has been proposed for preventing or reversing the neuropathy. Erythropoietin given systemically has a wide range of neuroprotective actions in animal models of central and peripheral nervous system damage. However, the erythropoietic action is a potential cause of side effects if erythropoietin is used for neuroprotection. We have successfully identified derivatives of erythropoietin, including carbamylated erythropoietin, which do not raise the hematocrit but retain the neuroprotective action exerted by erythropoietin.

EXPERIMENTAL DESIGN

We have developed previously an experimental chemotherapy-induced peripheral neurotoxicity that closely resembles CDDP neurotoxicity in humans. The present study compared the effects of erythropoietin and carbamylated erythropoietin (50 microg/kg/d thrice weekly) on CDDP (2 mg/kg/d i.p. twice weekly for 4 weeks) neurotoxicity in vivo.

RESULTS

CDDP given to Wistar rats significantly lowered their growth rate (P < 0.05), with slower sensory nerve conduction velocity (P < 0.001) and reduced intraepidermal nerve fibers density (P < 0.001 versus controls). Coadministration of CDDP and erythropoietin or carbamylated erythropoietin partially but significantly prevented the sensory nerve conduction velocity reduction. Both molecules preserved intraepidermal nerve fiber density, thus confirming their neuroprotective effect at the pathologic level. The protective effects were not associated with any difference in platinum concentration in dorsal root ganglia, sciatic nerve, or kidney specimens.

CONCLUSIONS

These results widen the spectrum of possible use of erythropoietin and carbamylated erythropoietin as neuroprotectant drugs, strongly supporting their effectiveness.

Chemotherapy for advanced gastric cancer

BACKGROUND

Gastric cancer currently ranks second in global cancer mortality. Most patients are either diagnosed at an advanced stage, or develop a relapse after apparently curative operation. Apart from supportive measures, systemic chemotherapy is the only treatment option available in this situation.

OBJECTIVES

To assess the effect of chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapy regimens in advanced gastric cancer.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2004), MEDLINE and EMBASE up to February 2004 and reference lists of articles. We also contacted pharmaceutical companies as well as national and international experts.

SELECTION CRITERIA

Randomised controlled trials on systemic intravenous chemotherapy versus best supportive care, combination versus single agent chemotherapy and different combination chemotherapies in advanced gastric cancer.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data. A third investigator was consulted in case of disagreements. We contacted study authors to obtain missing information.

MAIN RESULTS

Chemotherapy versus best supportive care consistently demonstrated a significant benefit in terms of overall survival in favour of the group receiving chemotherapy (Hazard Ratios (HR) 0.39; 95% confidence intervals (CI) 0.28 to 0.52). Combination versus single-agent chemotherapy provides evidence for a survival benefit in favour of combination chemotherapy (HR 0.85; 95% CI 0.76 to 0.96). Numbers included in these comparisons were 184 and 1338 participants respectively. This benefit is achieved at the price of increased toxicity in the combination chemotherapy arms. When comparing 5-FU/cisplatin-containing combination therapy regimens with anthracyclines versus those without anthracyclines (HR 0.77; 95% CI 0.62 to 0.95 based on 501 participants) and 5-FU/anthracycline-containing combinations with cisplatin versus those without cisplatin (HR 0.83; 95% CI 0.76 to 0.91 based on 1147 participants), there was a significant survival benefit for regimens including 5-FU, anthracyclines and cisplatin.

AUTHORS' CONCLUSIONS

Chemotherapy significantly improves survival in comparison to best supportive care. In addition, combination chemotherapy improves survival compared to single-agent 5-FU, but the effect size is much smaller. Among the combination chemotherapy regimens studied, best survival results are achieved with regimens containing 5-FU, anthracyclines and cisplatin. In this category, ECF (epirubicin, cisplatin and continuous infusion 5-FU) is tolerated best.

Chemotherapy-induced peripheral neuropathy: pathogenesis and emerging therapies

Peripheral neuropathy is a major dose-limiting side effect of many chemotherapeutic agents. The type and degree of neuropathy depend on the chemotherapy drug, dose-intensity, and cumulative dose. Disabling peripheral neuropathy has a significant negative impact on quality of life. Accordingly, a reliable assessment of chemotherapy-induced peripheral neurotoxicity is necessary, especially if potential neuroprotective agents are to be investigated. Chemoprotectants are agents that have been developed to ameliorate the toxicity associated with cytotoxic drugs. They aim to provide site-specific protection for normal tissues, without compromising antitumor efficacy. Several chemoprotectant compounds have been studied in recent clinical trials. These trials must include sufficient dose-limiting events for study and assessment of both toxicity and antitumor effect. A future avenue of investigation includes the identification of patients at higher risk for the development of peripheral neuropathy based on their genotype. Identification of these higher-risk patients may enable us to devise prevention strategies prior to the onset of this potentially debilitating complication.

Oxaliplatin-associated neuropathy: a review

OBJECTIVE

To review the incidence, mechanism, signs, symptoms, and management of oxaliplatin-induced neurotoxicity.

DATA SOURCES

English-language publications from the MEDLINE database (1995-August 2004), published articles, and meeting abstracts were reviewed.

STUDY SELECTION AND DATA EXTRACTION

Relevant data were extracted from published reports and abstracts on studies and case reports of humans with cancer who received oxaliplatin chemotherapy and in vitro studies of oxaliplatin neurotoxicity.

DATA SYNTHESIS

Neurotoxicity is a common adverse effect of oxaliplatin that usually presents as peripheral neuropathy. There are 2 forms of oxaliplatin-induced neurotoxicity: acute and chronic. The acute form occurs in >90% of patients and may begin during the infusion or within hours of completion, is usually self-limited, and may be exacerbated by exposure to cold. Chronic neuropathy is cumulative and is most commonly seen in patients who have received total doses > or =540 mg/m2. Although it is a sensory neuropathy, the intensity can increase to the point that it impairs physical functions, such as holding objects and writing. Preventive measures include administration of calcium and magnesium solutions, gabapentin, carbamazepine, amifostine, and glutathione. Treatment measures include calcium and magnesium solutions, gabapentin, and alpha-lipoic acid.

CONCLUSIONS

Peripheral neuropathy is seen in the majority of patients who receive oxaliplatin. The acute form is usually transient and self-limited; however, the chronic form can be dose-limiting. Calcium and magnesium solutions are an effective and convenient means of treating and reducing the severity of neuropathic symptoms. Additional studies, including controlled trials, are needed to determine the best way to prevent and treat this complication.

Supplementation with antioxidant micronutrients and chemotherapy-induced toxicity in cancer patients treated with cisplatin-based chemotherapy: a randomised, double-blind, placebo-controlled study

Cisplatin-induced toxicities are mainly caused by the formation of free radicals, leading to oxidative organ damage. Plasma concentrations of antioxidants decrease significantly during cisplatin chemotherapy for cancer. Forty-eight cancer patients treated with cisplatin-based chemotherapy were randomised in a double-blind manner to receive either supplementation with vitamin C, vitamin E and selenium dissolved in a beverage or to receive a placebo beverage. Primary outcome measures were the amount of nephrotoxicity and ototoxicity induced by cisplatin. No significant differences were found between the two study groups with respect to these primary outcome measures. However, patients who achieved the highest plasma concentrations of the three antioxidant micronutrients had significantly less loss of high-tone hearing. In addition, significant correlations were found between the reduced/oxidised vitamin C ratio and malondialdehyde (MDA), markers of oxidative stress, and cisplatin-induced ototoxicity and nephrotoxicity. The lack of protection against cisplatin-induced toxicities in patients in the intervention arm may be related to poor compliance and/or inadequate supplementation. Supplementation with a higher dose (intensity) and in combination with other antioxidants should be investigated further.

Toxicities of the platinum antineoplastic agents

The platinum agents (cisplatin, carboplatin and oxaliplatin) are among the most useful anticancer agents available to oncologists. The drugs have the potential to produce both mild and more serious side effects. However, in general, the platinum agents can be delivered with acceptable toxicity, even when used in combination chemotherapy regimens. Furthermore, with appropriate dose modifications, the large majority of patients who may benefit from this class of cytotoxic pharmaceutical drugs will be able to complete a planned therapeutic programme.

Pharmacology of anticancer drugs in the elderly population

Modifications to bodily functions and physiology are known to occur with age. These changes can have a considerable impact on the pharmacokinetic processes of absorption, distribution, metabolism and excretion and the pharmacodynamic properties of administered drugs. For many drugs with a high therapeutic index, this will be clinically unimportant, but for anticancer drugs, which usually have a low therapeutic index, these pharmacological changes can lead to dramatic consequences, such as excessive drug concentrations and unacceptable toxicity, or subtherapeutic drug concentrations and ineffective treatment. Despite the increased susceptibility of the elderly to these changes, doses are rarely adapted on the basis of pharmacokinetics and pharmacodynamics, with the exception of changes secondary to altered renal function. Until recently, only a few large prospective randomised trials have provided evidence-based data for dose adaptations in elderly patients. However, with increasing knowledge of the pharmacokinetics of anticancer drugs, advances in the knowledge of pharmacokinetic behaviour with aging, and documented efficacy and toxicity data in the elderly population, it is possible to highlight aspects of prescribing anticancer drugs in the elderly. In general, and for most drugs, age itself is not a contraindication to full-dose chemotherapy. The main limiting factors are comorbidity and poor functional status, which may be present in a significant number of the elderly population. Elderly patients with cancer are part of the daily practice of oncologists, but currently clinicians can often only estimate whether dose modification is advantageous for the elderly. This review attempts to elucidate the factors that can influence the pharmacokinetics of anticancer drugs frequently used in the elderly, and the clinical or biochemical parameters that form the basis for dose adjustments with age.

Neurotoxic complications of chemotherapy in patients with cancer: clinical signs and optimal management

Neurotoxic side effects of chemotherapy occur frequently and are often a reason to limit the dose of chemotherapy. Since bone marrow toxicity, as the major limiting factor in most chemotherapeutic regimens, can be overcome with growth factors or bone marrow transplantation, the use of higher doses of chemotherapy is possible, which increases the risk of neurotoxicity. Chemotherapy may cause both peripheral neurotoxicity, consisting mainly of a peripheral neuropathy, and central neurotoxicity, ranging from minor cognitive deficits to encephalopathy with dementia or even coma. In this article we describe the neurological adverse effects of the most commonly used chemotherapeutic agents. The vinca-alkaloids, cisplatin and the taxanes are amongst the most important drugs inducing peripheral neurotoxicity. These drugs are widely used for various malignancies such as ovarian and breast cancer, and haematological cancers. Chemotherapy-induced neuropathy is clearly related to cumulative dose or dose-intensities. Patients who already have neuropathic symptoms due to diabetes mellitus, hereditary neuropathies or earlier treatment with neurotoxic chemotherapy are thought to be more vulnerable for the development of chemotherapy-induced peripheral neuropathy. Methotrexate, cytarabine (cytosine arabinoside) and ifosfamide are primarily known for their central neurotoxic side effects. Central neurotoxicity ranges from acute toxicity such as aseptic meningitis, to delayed toxicities comprising cognitive deficits, hemiparesis, aphasia and progressive dementia. Risk factors are high doses, frequent administration and radiotherapy preceding methotrexate chemotherapy, which appears to be more neurotoxic than methotrexate as single modality. Data on management and neuroprotective agents are discussed. Management mainly consists of cumulative dose-reduction or lower dose-intensities, especially in patients who are at higher risk to develop neurotoxic side effects. None of the neuroprotective agents described in this article can be recommended for standard use in daily practise at this moment, and further studies are needed to confirm some of the beneficial effects described.

Nutritional Approaches to Late Toxicities of Adjuvant Chemotherapy in Breast Cancer Survivors

Adjuvant chemotherapy of breast cancer reduces recurrence rates and prolongs survival at the cost of both acute and chronic toxicities. Breast cancer survivors who have received adjuvant chemotherapy may suffer from late effects of chemotherapy including congestive heart failure, neuropathy, premature menopause, and osteoporosis. Nutritional approaches to these problems are distinct in their orientation and success. Study of free radical scavengers for anthracycline-induced cardiomyopathy was born from known pathogenetic mechanisms of cardiotoxicity but has been universally disappointing thus far in clinical trials. Application of agents used for diabetic neuropathy suggests that evening primrose oil, alpha-lipoic acid, and capsaicin may all play a role in the empiric options available to patients with chemotherapy-induced neuropathy. Plant-derived preparations including black cohosh (Actaea racemosa), dong quai (Angelica sinensis), evening primrose (Oenothera biennis), and red clover (Trifolium pretense) are used by patients experiencing hot flashes due to premature menopause despite a paucity of clinical trial data demonstrating either safety or efficacy. Calcium and vitamin D are widely accepted as an effective means to retard bone loss leading to osteoporosis. Nutritional approaches to late effects of breast cancer chemotherapy offer the prospect of preventing or ameliorating these sequelae of treatment. However, except for vitamin D and calcium for prevention of bone loss, current clinical evidence supporting use of nutritional agents remains sparse.

Neuroprotective effect of vitamin E supplementation in patients treated with cisplatin chemotherapy

PURPOSE

The aim of this study is to evaluate the neuroprotective effect of antioxidant supplementation with vitamin E in patients treated with cisplatin chemotherapy.

METHODS

Between April 1999 and October 2000, forty-seven patients were randomly assigned to either group one, which received vitamin E supplementation during cisplatin chemotherapy, or to group two, which received cisplatin chemotherapy alone. Alpha-tocopherol (vitamin E; 300 mg/d) was administered orally before cisplatin chemotherapy and continued for 3 months after the suspension of treatment. For preclinical studies, nude mice carrying the human melanoma tumor were treated with cisplatin alone or in combination with vitamin E.

RESULTS

Twenty-seven patients completed six cycles of cisplatin chemotherapy: 13 patients in group one and 14 patients in group two. The incidence of neurotoxicity was significantly lower in group one (30.7%) than it was in group two (85.7%; P <.01). The severity of neurotoxicity, measured with a comprehensive neurotoxicity score based on clinical and neurophysiological parameters, was significantly lower in patients who were supplemented with vitamin E than in patients who were not supplemented with vitamin E (2 v 4.7, P <.01). The results of the preclinical studies showed that when cisplatin was combined with vitamin E, no differences were observed in tumor weight inhibition, tumor growth delay, or life span as compared with treatment with cisplatin alone.

CONCLUSION

Supplementation of patients receiving cisplatin chemotherapy with vitamin E decreases the incidence and severity of peripheral neurotoxicity.