Cisplatin neuropathy. Clinical, electrophysiologic, morphologic, and toxicologic studies

Late complications of chemotherapy in testicular cancer

Cisplatin-based treatment has significantly increased survival in testicular cancer patients. Therefore, there has been enough interest for the late toxic effects of chemotherapy which affect the quality of life of the cancer survivors. These toxic effects may either persist or present long after the end of chemotherapy and involve the impairment of renal function, neurotoxicity, pulmonary toxicity and vascular disease. Also, a major issue experienced by a large number of patients is infertility, which has been improved due to modified surgical techniques, reduced treatment intensity, the use of sperm cryopreservation and methods of assisted reproduction. Physicians should also be aware of the risk of secondary malignancy development. Therefore, close follow-up of the testicular cancer survivors as well as, focus on minimizing treatment complications through improvement of treatment strategies are warranted.

Cisplatin overdose: toxicities and management

Cisplatin is one of the most widely used antineoplastic agents in the treatment of solid tumour and haematological malignancies, including cancers of the testes, ovary, bladder, head and neck, oesophagus, stomach and lung, as well as lymphoma and osteosarcoma. Its non-specific targeting commonly results in adverse effects and toxicities affecting the gastrointestinal, renal, neurological and haematological systems even when administered at standard doses. Since cisplatin-related toxicities are dose-dependent, these may be more pronounced in the setting of a cisplatin overdose, resulting in significant morbidity and/or mortality. The incidence of cisplatin overdoses is unknown; however, early-phase clinical trials utilizing high-dose cisplatin, and case reports in the overdose setting have characterized the clinical features associated with cisplatin overdoses, highlighting some therapeutic strategies for consideration. To date, no published guidelines exist for managing a cisplatin overdose. The major toxicities of a cisplatin overdose include nausea and vomiting, renal insufficiency, electrolyte abnormalities, myelosuppression, ototoxicity, peripheral neuropathy, hepatotoxicity and retinopathy. Diarrhoea, pancreatitis, seizures and respiratory failure have also been reported. No specific antidote for cisplatin exists. Key management principles and strategies to lessen toxicities include renoprotection and enhancing drug elimination with aggressive intravenous hydration with or without the use of an osmotic diuretic, and avoidance of nephrotoxic medications. Sodium thiosulfate and plasmapheresis, with or without haemodialysis support, should be strongly considered. Close monitoring of clinical and laboratory parameters, and institution of supportive therapies, including antiemetics and haematopoietic colony stimulating factor support, are warranted. Based on the current literature, experimental therapies such as amifostine, ditiocarb sodium (diethyldithiocarbamate), acetylcysteine, fosfomycin and colestipol are of limited clinical effectiveness and remain investigational. This review serves to highlight the clinical spectrum of toxicities resulting from a cisplatin overdose, to critically appraise the available literature and to present a suggested algorithmic approach for the initial management of a cisplatin overdose.

Polyvalent oligonucleotide gold nanoparticle conjugates as delivery vehicles for platinum(IV) warheads

Amine-functionalized polyvalent oligonucleotide gold nanoparticles (DNA-Au NPs) were derivatized with a cisplatin prodrug, and the resulting DNA-Au NP conjugates were used to internalize multiple platinum centers. A platinum(IV) complex, c,c,t-[Pt(NH(3))(2)Cl(2)(OH)(O(2)CCH(2)CH(2)CO(2)H)], was tethered to the surface of DNA-Au NPs through amide linkages. The platinum-tethered gold nanoparticles were taken into several cancer cells. The drop in intracellular pH facilitated reductive release of cisplatin from the prodrug, which then formed 1,2-d(GpG) intrastrand cross-links in the cell nuclei, as confirmed by an antibody specific for this adduct. The cytotoxicity of the platinum(IV) complex increases significantly in several cancer cell lines when the complex is attached to the surface of the DNA-Au NPs and in some instances exceeds that of cisplatin.

Testicular cancer: a prototypic tumor of young adults

Testicular cancer is the most common solid tumor among males in the 20- to 39-year age range. Moreover, testicular cancer has unique biological associations, clinical features, and psychosocial impacts that establish this tumor as a prototypic malignancy of young adults. The biology of testicular germ cell tumors after puberty is distinctive. Epidemiologic patterns of testicular cancer suggest etiologic factors that may be congenital, racial, and geographic. The clinical management of a cancer common among young adults, but rare among adults in general, requires expertise so as not to jeopardize the high rates of survivorship associated with modern therapy. The concurrent but separate development of staging, prognostic systems, and treatment recommendations between the fields of pediatric and adult oncology highlights the need for increased integration and cooperation across these subspecialties. The high rate of survival, combined with the need for long-term monitoring for relapse or late effects, demonstrates the challenge of delivering longitudinal care in this mobile and active young adult population.

Erythropoietin overrides the triggering effect of DNA platination products in a mouse model of cisplatin-induced neuropathy

BACKGROUND

Cisplatin mediates its antineoplastic activity by formation of distinct DNA intrastrand cross links. The clinical efficacy and desirable dose escalations of cisplatin are restricted by the accumulation of DNA lesions in dorsal root ganglion (DRG) cells leading to sensory polyneuropathy (PNP). We investigated in a mouse model by which mechanism recombinant erythropoietin (rhEPO) protects the peripheral nervous system from structural and functional damage caused by cisplatin treatment with special emphasis on DNA damage burden.

RESULTS

A cumulative dose of 16 mg cisplatin/kg resulted in clear electrophysiological signs of neuropathy, which were significantly attenuated by concomitant erythropoietin (cisplatin 32,48 m/s +/- 1,68 m/s; cisplatin + rhEPO 49,66 m/s +/- 1,26 m/s; control 55,01 m/s +/- 1,88 m/s; p < 0,001). The co-application of rhEPO, however, did not alter the level of unrepaired cisplatin-DNA lesions accumulating in DRG target cells. Micro-morphological analyses of the sciatic nerve from cisplatin-exposed mice showed damaged myelin sheaths and mitochondria. Co-administered rhEPO inhibited myelin sheaths from structural injuries and resulted in an increased number of intact mitochondria.

CONCLUSION

The protective effect of recombinant erythropoietin is not mediated by reducing the burden of DNA platination in the target cells, but it is likely to be due to a higher resistance of the target cells to the adverse effect of DNA damage. The increased frequency of intact mitochondria might also contribute to this protective role.

Neuronal expression of copper transporter 1 in rat dorsal root ganglia: association with platinum neurotoxicity

PURPOSE

We report the neuronal expression of copper transporter 1 (CTR1) in rat dorsal root ganglia (DRG) and its association with the neurotoxicity of platinum-based drugs.

METHODS

CTR1 expression was studied by immunohistochemistry and RT-PCR. The toxicity of platinum drugs to CTR1-positive and CTR1-negative neurons was compared in DRG from animals treated with maximum tolerated doses of oxaliplatin (1.85 mg/kg), cisplatin (1 mg/kg) or carboplatin (8 mg/kg) twice weekly for 8 weeks.

RESULTS

Abundant CTR1 mRNA was detected in DRG tissue. CTR1 immunoreactivity was associated with plasma membranes and cytoplasmic vesicular structures of a subpopulation (13.6 +/- 3.1%) of mainly large-sized (mean cell body area, 1,787 +/- 127 microm(2)) DRG neurons. After treatment with platinum drugs, the cell bodies of these CTR1-positive neurons became atrophied, with oxaliplatin causing the greatest percentage reduction in the mean cell body area relative to controls (42%; P < 0.05), followed by cisplatin (18%; P < 0.05) and carboplatin causing the least reduction (3.2%; P = NS). CTR1-negative neurons, with no immunoreactivity or only diffuse cytoplasmic staining, showed less treatment-induced cell body atrophy than CTR1-positive neurons.

CONCLUSIONS

CTR1 is preferentially expressed by a subset of DRG neurons that are particularly vulnerable to the toxicity of platinum drugs. These findings, together with its neuronal membrane localization, are suggestive of CTR1-related mechanisms of platinum drug neuronal uptake and neurotoxicity.

Evaluation of the cytotoxicity and genotoxicity of curcumin in PC12 cells

Neurotoxicity induced by reactive oxygen species can appear as an adverse effect of chemotherapy treatment with platinum compounds, such as cisplatin. The use of this drug in clinical practice is limited due to its adverse effects, including nephrotoxicity, ototoxicity, neurotoxicity and genotoxicity. Functional foods or nutraceuticals have demonstrated potential neuroprotective activity in several experiments and models. This study aimed to investigate the possible cytotoxicity and genotoxicity/antigenotoxic effects of curcumin in PC12 cells exposed to cisplatin. Cell viability and genotoxicity/antigenotoxicity were evaluated by the MTT assay and micronucleus test, respectively. PC12 cells were treated with different concentrations of cisplatin and curcumin (0.5 -- 128 microg/mL). Analysis of the results showed that high concentrations of curcumin were cytotoxic and increased micronuclei frequency compared to the control group. In the associated treatments, at all three concentrations evaluated, curcumin significantly reduced the total frequency of micronuclei induced by cisplatin. Determining the cytotoxic and genotoxic/antigenotoxic effects of this frequently used antioxidant in a neuronal model is important to assess possible hazards when combined with other chemical agents, including chemotherapy drugs used in cancer therapy.

Mice with cisplatin and oxaliplatin-induced painful neuropathy develop distinct early responses to thermal stimuli

Background

Cisplatin has been in use for 40 years for treatment of germ line and other forms of cancer. Oxaliplatin is approved for treatment of metastatic colorectal cancer. Thirty to forty percent of cancer patients receiving these agents develop pain and sensory loss. Oxaliplatin induces distinctive cold-associated dysesthesias in up to 80% of patients.

Results

We have established mouse models of cisplatin and oxaliplatin-induced neuropathy using doses similar to those used in patients. Adult male C57BL6J mice were treated with daily intraperitoneal injection for 5 days, followed by 5 days of rest, for two cycles. Total cumulative doses of 23 mg/kg cisplatin and 30 mg/kg oxaliplatin were used. Behavioral evaluations included cold plate, von Frey, radiant heat, tail immersion, grip strength and exploratory behavior at baseline and at weekly intervals for 8 weeks. Following two treatment cycles, mice in the cisplatin and oxaliplatin treatment groups demonstrated significant mechanical allodynia compared to control mice. In addition, the cisplatin group exhibited significant thermal hyperalgesia in hind paws and tail, and the oxaliplatin group developed significant cold hyperalgesia in hind paws.

Conclusion

We have therefore established a model of platinum drug-induced painful peripheral neuropathy that reflects the differences in early thermal pain responses that are observed in patients treated with either cisplatin or oxaliplatin. This model should be useful in studying the molecular basis for these different pain responses and in designing protective therapeutic strategies.

Implications of apurinic/apyrimidinic endonuclease in reactive oxygen signaling response after cisplatin treatment of dorsal root ganglion neurons

Peripheral neuropathy is one of the major side effects of the anticancer drug cisplatin. Although previous work suggests that this neuropathy correlates with formation of DNA adducts in sensory neurons, growing evidence suggests that cisplatin also increases the generation of reactive oxygen species (ROS), which could cause DNA damage. Apurinic/apyrimidinic endonuclease/redox factor-1 (Ape1/Ref-1) is a multifunctional protein involved in DNA base excision repair of oxidative DNA damage and in redox regulation of a number of transcription factors. Therefore, we asked whether altering Ape1 functions would influence cisplatin-induced neurotoxicity. Sensory neurons in culture were exposed to cisplatin for 24 hours and several end points of toxicity were measured, including production of ROS, cell death, apoptosis, and release of the immunoreactive calcitonin gene-related peptide (iCGRP). Reducing expression of Ape1 in neuronal cultures using small interfering RNA (siRNA) enhances cisplatin-induced cell killing, apoptosis, ROS generation, and cisplatin-induced reduction in iCGRP release. Overexpressing wild-type Ape1 attenuates all the toxic effects of cisplatin in cells containing normal endogenous levels of Ape1 and in cells with reduced Ape1 levels after Ape1siRNA treatment. Overexpressing the redox deficient/repair competent C65-Ape1 provides partial rescue, whereas the repair-deficient Ape1 (N226A + R177A) does not protect neurons from cisplatin toxicity. We also observe an increase in phosphorylation of p53 after a decrease in Ape1 levels in sensory neuronal cultures. These results strongly support the notion that Ape1 is a potential translational target such that protecting Ape1 levels and particularly its DNA repair function could reduce peripheral neuropathy in patients undergoing cisplatin treatment.

Amifostine protective effect on cisplatin-treated rat testis

Cisplatin is a potent drug used in clinical oncology but causes spermatogenesis damage. Amifostine is a drug used against toxicity caused by ionizing irradiation and chemotherapeutic drugs. Since cisplatin provokes fertility and induces germ cell apoptosis and necrosis, we proposed to evaluate the amifostine cytoprotective action on testes of cisplatin-treated rats. Thirty-day-old prepubertal Wistar rats received a single cisplatin dose of 5 mg/kg and were killed after 3, 6, and 12 hr. The hematoxylin-eosin stained testicular sections were submitted to histological, morphometric, and stereological analysis. The terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) method was used to label apoptotic cells. TUNEL-positive and TUNEL-negative germ cells with abnormal nuclear morphology (ANM) were scored. Significant alterations of greater part of the parameters occurred in the cisplatin-treated group (CE) compared to the group that received amifostine before the cisplatin-treatment (ACE); however, testicular weight and volume did not vary between these groups. Tubular diameter was reduced in CE in comparison to ACE rats, while interstitial tissue and lymphatic space volume and volume density were significantly higher in CE rats; interstitial testicular edema probably occurred in cisplatin-treated rats. CE rats showed important histological alterations, which were more accentuated than in ACE rats. The numerical densities of apoptotic germ cells and TUNEL-negative cells with ANM were lower in ACE than in CE rats. In conclusion, the amifostine previously administered to prepubertal rats reduced the testicular damage caused by cisplatin. We conclude that amifostine partially protected the rat seminiferous epithelium against cisplatin toxicity.

Ursodeoxycholic acid prevents apoptosis of mouse sensory neurons induced by cisplatin by reducing P53 accumulation

Ursodeoxycholic acid (UDCA), a component of bile acid, which is abundant in the gall bladder of bears, has been used in clinical medicine for cholestatic liver diseases. Recently, it was demonstrated that UDCA and its derivative tauroursodeoxycholic acid block apoptotic cell death in both hepatic and non-hepatic cells. Cisplatin, an effective anti-cancer drug, is known to cause sensory neuropathy in patients receiving the drug. In the present study, whether UDCA is effective in blocking cisplatin-induced cell death in mouse hybrid sensory neurons was conducted. N18D3 mouse hybrid sensory neurons exposed to cisplatin were found to undergo apoptotic cell death. Preincubation with UDCA completely blocked cisplatin-induced apoptotic cell death in the sensory neurons, and cisplatin-induced p53 accumulation was suppressed by UDCA treatment. These results indicate that UDCA has a neuroprotective effect on the cisplatin-induced neuronal cell death of sensory neurons via the downregulation of the p53 signaling pathway.

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.

3D conformal radiotherapy and cisplatin for recurrent malignant glioma

PURPOSE

To determine the maximum tolerated dose of 3D conformal radiotherapy in combination with Cisplatin for patients with recurrent malignant gliomas.

METHODS

From 1999-2003, nine patients with recurrent malignant glioma received fractionated radiotherapy and Cisplatin (20 mg/m2/d IV on days 1-5) in a Phase I radiation dose escalation trial. Three sequential dose levels were evaluated: 25 Gy, 30 Gy, and 35 Gy, using 5 Gy fractions. All patients received prior external beam radiation (median dose 59.4 (20-60) Gy) and five patients received prior chemotherapy.

RESULTS

Six male and three female patients were enrolled with a median age of 52 years, and a median Karnofsky performance status score of 70. The median re-irradiated tumor volume was 18.9 (0.1-78.5) cm3 and the median follow-up was 8.8 (3.2-31.2) months. One patient (30 Gy/ 6 fractions) experienced medically reversible acute grade 3 toxicity. A second patient (35 Gy/ 7 fractions) experienced acute grade 2 toxicity and histology showed tumor and radiation effect. A third patient (25 Gy/ 5 fractions) experienced late grade 3 toxicity from radiation necrosis. The radiological responses consisted of complete response (1 patient), partial response (1 patient), and stable disease (2 patients). The median overall survival was 8.8 months (95% CI 8.0-9.9), and the median disease free interval was 2.0 months (95% CI 1.4-4.4). Seven patients received chemotherapy following re-irradiation and Cisplatin.

CONCLUSION

The maximum tolerated dose of 3D conformal fractionated radiotherapy was 30 Gy in 6 fractions with low dose Cisplatin, which was well tolerated in terms of acute toxicity for our patient population. This regimen demonstrated only modest efficacy in the treatment of recurrent malignant glioma. Combinations of conformal re-irradiation and other systemic agents may merit investigation. Currently our recommended dose is 30 Gy in 6 fractions for selected patients.

Sensitivity after bilateral prophylactic mastectomy and immediate reconstruction

The purpose of this retrospective study was to evaluate the cutaneous somatosensory function and patients' subjective experience after bilateral prophylactic mastectomy and immediate reconstruction with implants. Twenty-four patients treated during an eight-year period were included. Somatosensory examination was made at least two years after the latest surgery to study perception thresholds to touch, warmth, cold, and heat pain, using quantitative techniques. Patients also completed a questionnaire about subjective sensitivity. Sixteen women who had had no previous breast surgery were used as a control group. Most patients reported decreased sensitivity in the breasts, which was confirmed by the results from the quantitative somatosensory examination. The results also showed that the ability to experience sexual feelings in the breast is usually lost after this type of operation, and as many as 14 patients reported spontaneous or stimulus-evoked discomfort in the breasts.

Repair capacity for platinum-DNA adducts determines the severity of cisplatin-induced peripheral neuropathy

The pronounced neurotoxicity of the potent antitumor drug cisplatin frequently results in the onset of peripheral polyneuropathy (PNP), which is assumed to be initially triggered by platination products in the nuclear DNA of affected tissues. To further elucidate the molecular mechanisms, we analyzed in a mouse model the formation and processing of the main cisplatin-induced DNA adduct (guanine-guanine intrastrand cross-link) in distinct neuronal cell types by adduct-specific monoclonal antibodies. Comparison of the adduct kinetics in cisplatin-injected mice either proficient or deficient for nucleotide excision repair (NER) functions revealed the essential role of this DNA repair pathway in protecting differentiated cells of the nervous system from excessive formation of such lesions. Hence, chronic exposure to cisplatin resulted in an accelerated accumulation of unrepaired intrastrand cross-links in neuronal cells of mice with dysfunctional NER. The augmented adduct levels in dorsal root ganglion (DRG) cells of those animals coincided with an earlier onset of PNP-like functional disturbance of their sensory nervous system. Independently from the respective repair phenotype, the amount of persisting DNA cross-links in DRG neurons at a given cumulative dose was significantly correlated to the degree of sensory impairment as measured by electroneurography. Collectively, these findings suggest a new model for the processing of cisplatin adducts in primary neuronal cells and accentuate the crucial role of effectual DNA repair capacity in the target cells for the individual risk of therapy-induced PNP.

Cisplatin-induced hair cell loss in zebrafish (Danio rerio) lateral line

We have used time-lapse imaging to study cisplatin-induced hair cell death in lateral line neuromasts of zebrafish larvae in vivo. We found that cisplatin-induced hair cell death occurred much more slowly than had been shown to occur in aminoglycoside-induced hair cell death. By prelabeling hair cells with FM1-43FX, and assessing hair cell damage, it was established that cisplatin causes hair cell loss in the lateral line in a dose-dependent fashion. The kinetics of hair cell loss during exposure to different concentrations of cisplatin was also assessed and it was found that the onset of hair cell loss correlated with the accumulated dose of cisplatin. These data demonstrate the feasibility and repeatability of cisplatin damage protocols in the zebrafish lateral line and set the stage for future evaluations of modulation of cisplatin-induced hair cell death.

Short- and long-term complications of therapy for testicular cancer

We review the treatments used for testicular cancer and the complications associated with each modality of therapy. It is imperative the clinician recognize possible treatment-related morbidity when counseling and monitoring testicular cancer patients.

Toxic neuropathies associated with pharmaceutic and industrial agents

Neuropathies associated with industrial, environmental, and pharmacologic toxicants are uncommon. Nevertheless, it is important to consider toxic etiologies in the differential diagnosis of neuropathies, because they are among the most treatable forms of peripheral nervous system dysfunction. The purpose of this article is to discuss the clinical investigation of a suspected toxic neuropathy, to review some of the more common or representative neurotoxicants, and to identify the methods for establishing causation.

Dysfunction in multiple primary afferent fiber subtypes revealed by quantitative sensory testing in patients with chronic vincristine-induced pain

Vincristine is one of the frontline chemotherapy drugs for the treatment of numerous lymphoid neoplasias. The main dose-limiting complication of vincristine is the development of painful peripheral neuropathy. Although clinical reports have appeared in the literature detailing the symptoms of vincristine neuropathy, quantitative sensory testing data that might yield insight to dysfunction in subsets of primary afferents are lacking. In this report, pain descriptors and anatomical distributions of sensory abnormalities were collected in each patient. Touch detection threshold, sharpness detection threshold, the thresholds for the detection of skin warming, heat pain, skin cooling, and the perception of cooling-induced pain were measured in patients with chronic vincristine-induced pain in each area of sensory abnormality and in skin perceived as outside the affected areas. Elevated touch detection thresholds were observed both within and outside areas affected by pain and sensory abnormality. Elevated sharpness and warm detection thresholds were noted only in areas affected by pain. These data suggest that chronic vincristine-induced pain is associated with dysfunction in Abeta, Adelta, and C caliber primary afferent fibers. Deficits in Abeta fibers appear to precede and presage deficits in the other fiber types, whereas deficits in Adelta- and C-fiber function appear to be specifically associated with the generation of pain.

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.

Pain management

This article provides information regarding treatments for the management of moderate to severe pain in patients who are at the end of life. Discussion focuses on the use of strong opioids and adjuvant analgesics. Special attention also is given to the most frequently used forms of interventional pain management. Although pain in terminally ill patients is not always related to cancer, many of the studies cited in this article were performed in cancer patients, a model that informs much of what is presented.

Prognostic ability of a good outcome to carpal tunnel release for decompression surgery in the lower extremity

For years, patients who were treated successfully with carpal tunnel release were told there was nothing that could be done about their lower extremity symptoms. Now that lower extremity nerve decompression has been accepted as an option to treat appropriate patients, the authors looked for correlations between a successful outcome with carpal tunnel syndrome and its predictive value of success for lower extremity nerve decompression. Data from a recent study demonstrate that a good result from upper extremity peripheral nerve surgery predicts the outcome for lower extremity peripheral nerve surgery in 88% of patients, and is, therefore, information valuable for prognosis and clinical decision-making.

Chemotherapy-induced neuropathy

Increasingly, surgeons are becoming aware of the successful treatment of symptomatic peripheral neuropathy by surgical decompression of peripheral nerves. Armed with the knowledge that patients can have underlying neuropathy with overlying anatomic compressions, surgeons have affected improvement in diabetes-induced neuropathy, neuropathy of unknown etiology, and chemotherapy-induced neuropathy. This article details the most well-known culprits in chemotherapy-induced neuropathy and discusses the putative mechanisms of action, medical management, and surgical data.

Diagnosis, management, and evaluation of chemotherapy-induced peripheral neuropathy

Peripheral neuropathy induced by cancer chemotherapy represents a large unmet need for patients due to the absence of treatment that can prevent or mitigate this common clinical problem. Chemotherapy-induced peripheral neuropathy (CIPN) diagnosis and management is further compounded by the lack of reliable and standardized means to diagnose and monitor patients who are at risk for, or who are symptomatic from, this complication of treatment. The pathogenesis and pathophysiology of CIPN are not fully elucidated, but there is increasing evidence of damage or interference with tubulin function. The diagnosis of CIPN may present a diagnostic dilemma due to the large number of potential toxic etiologies and conditions, which may mimic some of the clinical features; the diagnosis must be approached with care in such patients. The incidence and severity of CIPN is commonly under-reported by physicians as compared with patients. The development of new and reliable methods for the assessment of CIPN as well as safe and effective treatments to prevent this complication of treatment would represent important medical advancements for cancer patients.

Cisplatin-induced apoptosis in cultures of human Schwann cells

To investigate the sensitivity of human Schwann cells to cisplatin (cis-DDP), different approaches to estimate DNA damage were used: the comet assay, morphological evaluation of the granular condensation of nuclear chromatin and the terminal transferase-mediated dUTP nick-end-labelling (TUNEL) method. The number of micronuclei (MNi), as a sign of cisplatin-induced genotoxicity, was counted. DNA damage assessed by the comet assay was already evident after 1.5 microM cisplatin treatment at all exposure times (24, 48, and 72 h). Initial morphological changes characterised by the granular condensation of nuclear chromatin were detectable after 24 h exposure to 25 microM cis-DDP, while an increased number of apoptotic cells, determined by the TUNEL method, was noted after 48 h exposure to the same concentration. The first significant increase in the number of MNi was observed in cells treated with 75 microM cis-DDP for 24 h. We demonstrate that the comet assay is a highly sensitive method for measuring cisplatin induced DNA damage. Morphological observation revealed advanced as well as less prominent alterations in the nuclear chromatin. In contrast, the TUNEL method detected only those cells with advanced DNA fragmentation.

Cisplatin preferentially binds to DNA in dorsal root ganglion neurons in vitro and in vivo: a potential mechanism for neurotoxicity

Cisplatin causes apoptosis of dorsal root ganglia (DRG) neurons. The amount of platinum binding to DNA correlates with cisplatin toxicity in cancer cellsGenomic DNA platinum content of cultured embryonic DRG neurons and PC12 cells was assayed using inductively coupled plasma mass spectrometry (ICP-MS). Throughout these studies, "cisplatin" refers to the specific drug; "platinum" to the bound form of the drug that is measured in ICP-MS.. Cisplatin binds neuronal DNA more than a neuron-like dividing cell line (PC12); 10-fold at 24 h and 24-fold greater at 72 h. Difference in platinum accumulation was not due to dividing versus post-mitotic state, or to a difference in rate of repair. There was overall greater accumulation of platinum in DRG neurons. In vivo DNA-Platinum binding in adult (300 g) rat DRG was greater than in multiple other tissues. Concomitant treatment with high-dose NGF prevented cisplatin-mediated neuronal apoptosis in vitro but did not reduce adduct formation. Our results show that NGF does not alter platination of DNA, indicating that it interrupts the platinum death pathway after adduct formation. In addition, disproportionate platinum accumulation may explain why a drug aimed at killing rapidly dividing cells causes sensory neurotoxicity.

Role of ERK activation in cisplatin-induced apoptosis in A172 human glioma cells

Cisplatin activates multiple signal transduction pathways associated with cell survival and apoptosis in various cell types. The present study was undertaken to determine the role of extracellular signal-regulated protein kinase (ERK), a member of the mitogen-activated protein kinase family, in cisplatin-induced apoptosis in human glioma cells. Cisplatin resulted in apoptosis in a dose- and time-dependent manner. Cisplatin-induced apoptosis was prevented by the hydrogen peroxide scavenger pyruvate and the antioxidant N-acetylcysteine, but not by the superoxide scavenger tiron. Western blot analysis demonstrated that cisplatin treatment induced time-dependent activation of ERK, which was inhibited by chemical inhibitors of the MEK signaling pathway (PD98059 and U0126) and N-acetylcysteine. These inhibitors prevented cisplatin-induced cell death. Transient transfection of constitutive active MEK1 increased cisplatin-induced apoptosis. Cisplatin resulted in a reduction in mitochondrial membrane potential and its effect was prevented by N-acetylcysteine and PD98059. Caspase inhibitors (Boc-D-FMK and zDEVD-FMK) protected against cisplatin-induced cell death. Cisplatin-induced activation of caspase-3 was inhibited by N-acetylcysteine and PD98059. Taken together, these findings suggest that the ERK activation plays an active role in mediating cisplatin-induced apoptosis of human glioma cells and functions upstream of mitochondrial dysfunction and caspase activation to the initiate the apoptotic signal.

Taxol-induced sensory disturbance is characterized by preferential impairment of myelinated fiber function in cancer patients

Taxol produces neuropathic pain with three distinct zones of involvement in the extremities. Most distally is an area of on-going pain and proximal to this is a zone of sensory disturbance but not overt pain. These two areas were confined in all but one case to the glabrous skin of the hands and/or feet. More proximal is an area not recognized by the patients as involved with pain or sensory disturbance yet wherein quantitative sensory tests nevertheless reveal altered sensibility. Impairment of perception to light touch, normally conveyed by myelinated fibers, was dramatically altered in all three areas, being approximately 50-fold greater than normal in areas of pain and sensory disturbance as well as in areas of skin perceived by the patients as not affected. Impairment of perception to sharpness, normally conveyed by small myelinated fibers, was most pronounced in areas of on-going pain, intermediate in areas of sensory disturbance and near baseline in more proximal skin of chemotherapy patients. In contrast to mechanical sensibility, thermal thresholds for warm and heat pain detection were normal throughout. Finally, chemotherapy patients showed paradoxical burning pain to skin cooling that was most pronounced in proximal areas of skin thought to be unaffected by the patients, intermediate in the border zone of altered sensibility and least pronounced in areas of on-going pain. These data suggest that taxol produces a neuropathy characterized by pronounced impairment of function in A-beta myelinated fibers, intermediate impairment of A-delta myelinated fibers, and a relative sparing of C-fibers.

WR-2721 (Amifostine) ameliorates cisplatin-induced hearing loss but causes neurotoxicity in hamsters: dose-dependent effects

Chemoprotective agents reduce the toxic side effects of chemotherapy agents such as cisplatin. The conventional belief is that the chemoprotective agent WR-2721 (Amifostine), while protecting against most cisplatin-induced side effects, does not protect against cisplatin-induced ototoxicity (i.e., hearing loss). There is no knowledge, however, about the efficacy of high doses of WR-2721 (WR) in possibly protecting against cisplatin-induced ototoxicity. Thus, the dose-dependent effects of WR in possibly ameliorating cisplatin-induced ototoxicity were investigated. Hamsters were given a series of 5 cisplatin injections (3 mg/kg/injection once every other day, i.p.) either alone or in combination with 18, 40, 80, or 400 mg/kg/injection of the rescue agent WR ( n = 5 or 10/group). Other groups received either 80 mg/kg/injection WR alone ( n = 5) or were untreated ( n = 14). Ototoxicity was assessed by auditory brain stem responses (ABR). WR provided dose-dependent rescue from cisplatin's ototoxicity with no protection at the low dose of 18 mg/kg, moderate protection at 40 mg/kg, and nearly complete protection at 80 and 400 mg/kg. However, WR doses of 40 mg/kg or higher caused neurotoxicity as evidenced by prolongations in the ABR's interpeak latencies. Thus, high doses of WR provided the beneficial effect of protecting against cisplatin-induced ototoxicity, but had the harmful side effect of neurotoxicity. Previous failures to find chemoprotection from cisplatin-induced ototoxicity were likely due to the use of WR doses that were too small. The clinical implications of the beneficial and harmful effects of high doses of WR are discussed.

Changes in biophysical parameters of plasma membranes influence cisplatin resistance of sensitive and resistant epidermal carcinoma cells

The mechanism of resistance of cancer cells to the anticancer drug cisplatin is not fully understood. Using cisplatin-sensitive KB-3-1 and -resistant KCP-20 cells, we found that the resistant cells have higher membrane potential, as determined by membrane potential sensing oxonol dye. Electron spin resonance and fluorescence polarization studies revealed that the resistant cells have more "fluid" plasma membranes than the sensitive cells. Because of this observed difference in membrane "fluidity," we attempted modification of the plasma membrane fluidity by the incorporation of heptadecanoic acid into KB-3-1 and KCP-20 cell membranes. We found that such treatment resulted in increased heptadecanoic acid content and increased fluidity in the plasma membranes of both cell types, and also resulted in increased cisplatin resistance in the KCP-20 cells. This finding is in accord with our results, which showed that the cisplatin-resistant KCP-20 cells have more fluid membranes than the cisplatin-sensitive KB-3-1 cells. It remains to be determined whether the observed differences in biophysical status and/or fatty acid composition alone, or the secondary effect of these differences on the structure or function of some transmembrane protein(s), is the reason for increased cisplatin resistance.

Spinal cord stimulation relieves chemotherapy-induced pain: a clinical case report

We present two patients with chemotherapy-induced painful neuropathy that had been poorly controlled with medications but successfully treated with spinal cord stimulation (SCS). A trial period of SCS provided effective pain relief in both patients who subsequently underwent permanent stimulator implantation. Psychophysical tests were performed before and after the implantation of trial and permanent stimulators. SCS improved pain scores and facilitated a reduction of medications. Both patients reported improved gait and one of them also reported an increase in leg flexibility. Psychophysical tests demonstrated an improvement in touch and sharpness detection thresholds. In summary, SCS offers a therapeutic option for patients with chemotherapy-induced peripheral neuropathy who have poor pain relief with standard medical treatment.

Long-term complications of chemotherapy for germ cell tumours

Testicular cancer is the most common solid tumour among young males aged 15-35 years. Cisplatin-based combination chemotherapy has changed the outlook of this disease. Disseminated testicular cancer, once uniformly fatal, now has a cure rate of more than 80% with combination chemotherapy. Systematic randomised trials have shown that cisplatin, etoposide and bleomycin (PEB) combination chemotherapy remains the mainstay of treatment. While there is a high cure rate with chemotherapy in patients with this disease, some long-term complications from chemotherapy have now been recognised, including secondary leukaemia, therapy-related solid tumours, nephrotoxicity, neurotoxicity, pulmonary toxicity, vascular toxicity and infertility. Etoposide, a DNA topoisomerase II inhibitor, is a significant risk factor for developing leukaemia; the risk appears to be correlated with the total dose given. Patients receiving cisplatin-based combination chemotherapy for testicular cancer also appear to have a higher relative risk for developing second non-germ cell malignancies; the greatest risks for therapy-related solid tumours were seen with a combination of radiation therapy plus chemotherapy. Long-term vascular toxicities associated with chemotherapy include Raynaud's phenomenon, acute myocardial infarction and cerebrovascular events. Bleomycin is thought to be the most important drug in the pathogenesis of Raynaud's phenomenon, while cisplatin is the most likely agent involved in myocardial infarction. Peripheral neuropathy is the most common form of neurotoxicity observed with cisplatin-based chemotherapy. Risk factors for the development of neural damage include a high cumulative dose of cisplatin, the use of vinblastine and the concomitant development of Raynaud's phenomenon. Cisplatin is also well known to cause significant nephrotoxicity. Approximately 25% of patients present with azoospermia after undergoing combination chemotherapy with a follow up of 2-5 years. Physician awareness of complications associated with chemotherapy is vital to maximise efficacy, minimise toxicity, and preserve quality of life after treatment. Sperm cryopreservation should be considered for patients who desire children. Close monitoring during therapy allows for the early diagnosis of complications, and close follow up of patients after the completion of therapy is necessary to monitor for relapse and development of long-term complications such as myelodysplastic syndrome and leukaemia. Despite these complications, given the potential for cure rates in this young group of patients, the benefits far outweigh the risks.

Transscleral permeability and intraocular concentrations of cisplatin from a collagen matrix

This study determined the in vitro permeability of cisplatin through isolated human sclera as delivered by a collagen matrix vehicle. Short-term and long-term intraocular levels of cisplatin were also measured in the rabbit eye after a subconjunctival injection. Cisplatin in either a collagen matrix vehicle or a control balanced salt solution (BSS) vehicle was applied to human sclera mounted in a specially designed in vitro perfusion chamber. The amount of cisplatin that diffused across the sclera was measured in hourly samples for 24 h using atomic absorption spectrometry. In vivo studies were also performed in Dutch Belted rabbits given subconjunctival injections of cisplatin in collagen matrix or in BSS. Eyes were enucleated at 1.5 h and 2 weeks after injection, frozen, and dissected to determine the intraocular cisplatin concentrations. Cisplatin had a peak in vitro scleral permeability constant of 8.3+/-1.2 x 10(-6) and 20.1+/-1.8 x 10(-6) cm/s, delivered in collagen matrix and in BSS, respectively (mean+/-S.D.). At the end of the in vitro experiments, 35.9+/-4.6% of the cisplatin remained in the collagen matrix, while 0.8+/-0.2% remained in the BSS vehicle. Subconjunctival injection of cisplatin in the collagen matrix vehicle achieved 3.3+/-0.1 microg/ml in the vitreous humor at 1.5 h and 0.1+/-0.1 microg/ml at 2 weeks. This vehicle also achieved a cisplatin concentration of 73.5+/-23.9 microg/mg in the choroid and retina at 1.5 h and 3.2+/-1.3 microg/mg at 2 weeks. Compared to BSS, the collagen matrix vehicle provided a more controlled release of cisplatin, and after subconjunctival injection into rabbits, attained higher drug levels in several ocular tissues.

Neuromuscular complications of cancer

Neuromuscular complications of cancer are common and can affect any component of the peripheral nervous system from peripheral nerve cell body to muscle. Perhaps the most common complication is a length-dependent symmetric axonal polyneuropathy that is often multifactorial in etiology, resulting from metabolic and treatment effects of the primary malignancy. However, neuromuscular disorders may also be the presenting complaint in many conditions, including disorders caused by malignant infiltration of nerve and disorders cause by paraneoplastic syndromes. Although many of the paraneoplastic conditions are poorly responsive to treatment, not all are, and one hopes that prompt diagnosis of the underlying malignancy will lead to improved patient outcome. Recognition of iatrogenic neuromuscular complications is also important to modify treatment protocols when possible and thus decrease the risk of long-term neurologic disability.

Neurologic complications of cancer therapy

Neurologic complications of chemotherapy are relatively common. The diagnosis of chemotherapy-associated neurotoxicity remains a clinical one, and is largely based on the exclusion of other possible causes. The goal of this review is to describe the neurotoxicity associated with established chemothrerapeutic agents and with some of the newer biologic agents, monoclonal antibodies and targeted molecular therapies used in the treatment of cancer.

Novel therapeutic approaches in the treatment of children with hepatoblastoma

Hepatoblastoma is the most common liver tumor diagnosed in children. Children with persistently unresectable disease, metastatic disease at presentation, recurrent disease, or slowly declining alpha-fetoprotein levels are at high risk for recurrence, exhibit an extremely poor prognosis, and are in desperate need of novel therapeutic agents and strategies. Four high-risk patients were treated. One patient with a local recurrence was treated with irinotecan followed by orthotopic liver transplant. Three patients were treated with tandem high-dose chemotherapy (HDT) with autologous stem cell rescue (two with primary metastatic disease and one with recurrent disease). All three of the patients treated with HDT had relapse (two of them subsequently received irinotecan); the remaining patient underwent surgical resection of a solitary recurrent pulmonary metastasis. Irinotecan demonstrated significant antitumor effects in all three treated patients and was well tolerated. None of the three patients treated with HDT remained disease-free, although the patient who underwent surgical resection of a solitary recurrent pulmonary metastasis remains disease-free 6 years from diagnosis. Further exploration of the use of irinotecan is warranted in high-risk patients with hepatoblastoma.

Viral and non-viral gene therapy partially prevents experimental cisplatin-induced neuropathy

Sensory neuropathies are a frequent and dose-limiting complication resulting from treatment with cisplatin. Neurotrophin-3 (NT-3) promotes the survival of the large fiber sensory neurones that are impaired in cisplatin-induced neuropathy, and may therefore serve as a preventive agent. However, the short half-life of recombinant NT-3 after systemic administration limits its clinical applications. We compared two muscle-based gene transfer strategies for the continuous delivery of NT-3 to the bloodstream in an experimental model of cisplatin-induced neuropathy. Electrophysiological studies showed that the intramuscular injection of an adenovirus encoding NT-3 partially prevented the cisplatin-induced increase in sensory distal latencies. Similar effects were observed in cisplatin-treated mice that received intramuscular injections of a plasmid encoding NT-3 associated with in vivo electroporation. The two techniques were well tolerated and induced only slight muscle toxicity. Measurement of renal function, weight and survival showed that neither technique increased the toxicity of cisplatin. Our study shows that gene therapy, using either a viral or a non-viral vector, is a promising strategy for the prevention of cisplatin-induced neuropathy.

Local chemotherapy with cisplatin-depot for glioblastoma multiforme

Glioblastoma multiforme (GBM) makes up as many as 30% of all primary brain tumors. Despite the employment of multimodal antitumor treatment, the overall survival is less than one year. Between 06/01/1998 and 06/01/2000 17 patients (Group A) with GBM (11 males, 6 females; median age 54.3 years) were administered local chemotherapy with cisplatin incorporated into biodegradable 6-carboxylcellulose polymer (cisplatin-depot (CDDP-D)). After the subtotal removal of GBM, twenty 1.5 x 1.5 cm polymer plates with a total area of 45 cm2 (the density of cisplatin immobilization on 6-carboxylcellulose being 1 mg/cm2, a total cisplatin dose of 45 mg) were implanted into the tumor bed. Group B (21 patients with GBM; 11 males, 10 females; median age 53.2 years) was control: the subtotal tumor ablation without CDDP-D implantation. Two to three weeks after the surgery all the patients of Groups A and B started a course of radiation therapy. A total dose of cranial irradiation was 20 Gy (1 fraction/day, 5 days/week; a daily dose of 2 Gy) followed by a boost tumor bed irradiation (1 fraction/day, 5 days/week; a daily dose of 2 Gy) up to the conventional dose of 60 Gy. Survival data for the patients were processed using the Kaplan-Meier method and analyzed by logrank test. All the patients of Group A tolerated surgical ablation of the brain tumor without side effects (brain edema, seizures, etc.). No patient of Group A had a reduction in blood cell counts during six weeks that would indicate systemic exposure to cisplatin. Blood chemistry and urinalysis did not show evidence of renal injury. No side effects of radiotherapy were registered in Group B either, regarding both the psychoneurological status of the patients and the basic values of homeostasis. Karnofsky performance scale (KPS) score of Group A and Group B patients demonstrated no significant differences before and after the surgery. The median overall survivals for patients of Group A and Group B were 427.5 and 211.0 days respectively (p = 0.00001; overall logrank test). Conclusion. Local chemotherapy of GBM with CDDP-D followed by irradiation is well tolerated and effective.

Phase III evaluation of nortriptyline for alleviation of symptoms of cis-platinum-induced peripheral neuropathy

Tricyclic antidepressants have been reported to relieve the paresthesiae associated with peripheral neuropathies of many etiologies. We designed a randomized, double-blind, placebo-controlled, crossover trial to establish the efficacy of nortriptyline in the treatment of cis-diamminedichloroplatinum (CDDP)-induced paresthesiae. The study included 51 evaluable patients with CDDP-induced peripheral neuropathy and painful paresthesiae. The study consisted of two 4 week phases, separated by a 1 week 'wash-out' period, in which patients received escalating dosages of either placebo or nortriptyline. The target maximum dose of nortriptyline was 100 mg/day. Each patient filled out pre-randomization and then weekly questionnaires assessing paresthesiae severity, hours of sleep, quality of life, and adverse effects over the 9 week study. No significant differences in paresthesia were observed in the first treatment period between nortriptyline and placebo (means of 49 and 55 respectively on a 0-100 point scale, P=0.78). Although some evidence of a modest effect in favor of nortriptyline was observed during the second treatment period (about one patient in five got a 10-point reduction in pain from drug above placebo effect), this occurred in the presence of a strong carryover effect. Linear models analysis and Bayes methods confirmed that the effect of nortriptyline on paresthesia was modest at best. Hours of sleep increased in the nortriptyline phase (P=0.02). There was no significant difference in measures of quality of life and the effect of paresthesiae on patients' daily activities between nortriptyline and placebo. There was no major toxicity associated with nortriptyline, but dry mouth, dizziness, and constipation were more common with nortriptyline. In summary, nortriptyline failed to demonstrate strong evidence of any effect on paresthesia or pain. The presence of a potential effect which appeared in the second period of the crossover design is questionable due to the observed carryover effect. Cross-validation sensitivity analysis of results support the conclusion that nortriptyline provides modest improvement at best over placebo in terms of chemotherapy-related neuropathy.

Cisplatin-induced apoptosis of DRG neurons involves bax redistribution and cytochrome c release but not fas receptor signaling

Cisplatin causes apoptosis of DRG neurons in vitro and in vivo that can be prevented by high dose NGF. Design of a neuronal rescue strategy for patients receiving cisplatin will be facilitated by knowledge of the mechanism by which cisplatin causes DRG death. Inhibition of the fas receptor/ligand interaction prevents apoptosis in certain cancer cell lines treated with DNA damaging agents, including cisplatin. We demonstrated that killing curves from mice lacking a functional fas receptor and wild-type controls were not different over a wide range of therapeutically relevant concentrations. However, cisplatin treatment of DRG caused redistribution of cytosolic bax and mitochondrial release of cytochrome c. Bax redistribution was prevented by high dose NGF. This demonstrates for the first time that cisplatin does not signal for death via the fas pathway, but it does initiate the mitochondrial stress pathway in neurons and that NGF blocks death upstream of bax redistribution.

D-Methionine and cisplatin ototoxicity in the guinea pig: D-methionine influences cisplatin pharmacokinetics

D-Methionine has recently been advocated as a protectant against cisplatin toxicity. The use of systemic D-methionine as a protector was studied in 58 guinea pigs. Kinetics and distribution of [11CH(3)]D-methionine was analysed by positron emission tomography. Cisplatin and the monohydrated complex of cisplatin was quantified in blood ultrafiltrate using reversed-phase liquid chromatography with post-column derivatisation. Administration of 300 mg/kg of D-methionine caused a 30% decrease in the area under the concentration-time curve (AUC) of cisplatin. The toxic effect of cisplatin was studied after dose adjustment of cisplatin, i.e. with similar cisplatin AUC in the group receiving D-methionine and the saline control group. A significant ototoxic effect, measured as difference in pre- and 96 h post-treatment electrophysiological hearing threshold (auditory brainstem response), was observed at stimulus frequencies of 30 and 20 kHz. There was no difference between the groups in the extent of threshold shift. Quantitative outer hair cell counts showed a similar loss of cells in the two groups. All animals had a significant increase in plasma-creatinine but there was no difference between the groups. The results indicate that protection from cisplatin ototoxicity by systemic D-methionine can be explained by a lowered systemic exposure to the drug.

Evaluation of long-term toxicity in patients after cisplatin-based chemotherapy for non-seminomatous testicular cancer

BACKGROUND

Because of the increasing number of long-term survivors of metastatic testicular germ-cell cancer, a general concern has been secondary morbidities, especially cardiovascular risk factors.

PATIENTS AND METHODS

Thirty-two patients treated with cisplatin- and doxorubicin-containing chemotherapy > or = 13 years before the time of analyses were evaluated for neuro-, oto-, pulmonary-, vascular- and gonadal toxicity including evaluation of myocardial damage and cardiovascular risk factors and analysis of microcirculation.

RESULTS

Thirty percent of the patients showed abnormal left ventricle function. Elevated follicle stimulating hormone (FSH) and luteinising hormone (LH) levels in 75% of patients were often associated with low testosterone levels. Elevated total cholesterol levels were found in 82% and higher triglyceride levels in 44% of patients, most of them were overweight. About 25% of the patients developed diastolic arterial hypertension after chemotherapy. Reduced hearing was confirmed in 23% of patients, especially at frequencies higher than 3000 Hz. Moreover, 53% of patients presented transient evoked otoacoustic emissions. In 38% of patients non-symptomatic neuropathy was detected, in 28% symptomatic neuropathy, and in 6% disabling polyneuropathy. In 80% of patients with neuropathic symptoms additional morphological and functional abnormalities were found by nailfold capillary videomicroscopy, compared to only 57% of the patients without neuropathic symptoms.

CONCLUSIONS

Patients cured by cisplatin-based chemotherapy for metastatic testicular cancer have to be cognizant of their unfavorable cardiovascular risk profile, that might be a greater risk than developing a relapse or second malignancy.

Calpain immunoreactivity and morphological damage in chinchilla inner ears after carboplatin

Carboplatin produces an unusual pattern of damage in the chinchilla inner ear, characterized by early destruction of type I afferent fibers and preferential loss of type I hair cells in the vestibular end organs and inner hair cells (IHCs) in the cochlea. In the present study, we investigated a potential role of calpains, a family of calcium-activated proteases, in carboplatin ototoxicity. Chinchillas received carboplatin (100 mg/kg IP) and were sacrificed 12, 24, 48, or 72 h later for morphological evaluation or immunocytochemistry. Nerve fibers and myelin were the initial sites of increased calpain immunoreactivity (IR) and morphological damage. At 12 h, granular immunoreactive puncta were present within nerve fibers and their myelin sheaths in the spiral ganglion. In the habenula perforata, dense reaction product was present in large vacuoles in the myelin surrounding the nerve fibers. At 24 h, nerve fibers and myelin were destroyed in the habenula, and those in the spiral ganglion showed increased calpain IR and morphological damage. At 72 h, nerve fibers and myelin were completely destroyed. Calpain IR was not a prominent feature of IHCs, type I vestibular hair cells, or ganglion cells at any time after carboplatin. The results show a correlation between calpain IR and carboplatin-induced axon and myelin degeneration. We propose that calpain-induced axonopathy and myelinopathy are primary features of carboplatin ototoxicity in chinchilla.

Retreatment with dose-dense weekly cisplatin after previous cisplatin chemotherapy is not complicated by significant neuro-toxicity

Cisplatin induces a cumulative dose-dependent axonal sensory neuropathy. With a cumulative dose over 600 mg/m2, a significant percentage of patients will develop a moderate or severe neuropathy. We retreated patients with progressive or recurrent ovarian cancer after previous platinum-containing chemotherapy with weekly 50-70 mg/m2 cisplatin for six cycles. This group was prospectively followed for the development of neuropathy. Patients received six weekly cycles of either 50 or 70 mg/m2 cisplatin, combined with oral etoposide. Responding patients continued treatment with daily oral etoposide for nine months. Neurological toxicity was assessed with a sensory sum score, the sensory neuropathy common toxicity criteria (CTC) and quantitated sensory analysis of the vibration perception threshold (VPT). Neurological assessment was scheduled at baseline, after three cycles, at the end of cisplatin chemotherapy and at 3 monthly intervals until 1 year after the discontinuation of chemotherapy. The first evaluation carried out in the interval of 1-4 months after the end of weekly cisplatin therapy was taken as the principle evaluation for neurotoxicity because during this time interval the nadir of cisplatin neurotoxicity is to be expected. Of 89 patients evaluated for neurological toxicity, 80 patients were fully evaluable. Forty-nine had received prior cisplatin (median cumulative dosage 450 mg/m2); the others had received prior treatment with carboplatin. Cisplatin pretreated patients had slightly higher neuropathy scores at the start of weekly cisplatin. Almost all cisplatin pretreated patients received six cycles of cisplatin, 29 at 50 mg/m2 and 20 at 70 mg/m2 per cycle. Despite treatment up to an overall cumulative dose of 750-900 mg/m2 cisplatin, only 1 patient discontinued treatment due to neurotoxicity. One other patient developed a grade 3 neuropathy during follow-up. Only a marginal increase of neuropathic signs and symptoms were observed in all the other patients. In multiple regression analysis, the increase in VPT or the sensory sum score was not related to prior treatment (cisplatin or carboplatin). Patients with mild signs of neuropathy after prior treatment with cisplatin to a cumulative dose level of 400-450 mg/m2 can be retreated with weekly cisplatin to a cumulative dose of 420 mg/m2 (overall cumulative dose up to 800-900 mg/m2) with only a minimal risk of significant neurotoxicity.

Alterations in cell cycle regulation underlie cisplatin induced apoptosis of dorsal root ganglion neurons in vivo

Cisplatin is used in the treatment of ovarian and testicular cancer. Twenty percent of patients cannot be optimally treated because of sensory neurotoxicity. Human and animal studies demonstrate that the dorsal root ganglion neuron is the primary target of drug injury. We have previously demonstrated that cisplatin causes neuronal apoptosis in vitro. We now report a reproducible animal model of cell death induced by cisplatin. Drug was administered for 1 or 2 cycles of 5 days separated by 5 days. Total dose administered was 0, 5, 7.5, 10, or 15 mg/kg. Ganglia from 34 animals were processed and examined using in situ hybridization for cyclin D1 messenger RNA and digoxigenin coupled TUNEL staining. Overall, 2.9 +/- 3.9% of neurons were TUNEL positive in treated rats compared with 0.2 +/- 0.3% in controls (P <.005). There was a strong positive correlation (r2 = 0.88; P = 0.018) between percentage of TUNEL stained DRG and cumulative dose of cisplatin. Two independent approaches to quantitation of in situ cyclin D1 hybridization were used; blinded grading by an observer and measurement of color density using digital image analysis. Both demonstrated dramatic upregulation of expression of cyclin D1 mRNA in treated compared with control rats. This demonstrates that apoptosis of neurons is preceded by aberrant reentry into G1 phase of the cell cycle in an animal model.

Occult Small Cell Lung Cancer Associated with Paraneoplastic Neurologic Syndrome: Case Report

Cancer is often associated with paraneoplastic syndromes, which may be misinterpreted. We report a case of a patient with occult small cell lung cancer that was initially compounded by clinical features of a paraneoplastic neurologic syndrome. The presence of antineuronal antibodies and positron emission tomography scan guided the search for the underlying tumor.

Following chemo-radiotherapy the patient showed no evidence of disease for the next 18 months, whereas only a slight improvement in the neurologic disorders was observed. The course of the small cell lung cancer was very indolent and the paraneoplastic neurologic syndrome did not worsen with the use of cisplatin.