Safety and pharmacokinetics of temozolomide using a dose-escalation, metronomic schedule in recurrent paediatric brain tumours

The aims of this study were to determine the maximum tolerated dose (MTD), toxicity and pharmacokinetics of oral temozolomide administered over 42 d in children with recurrent/refractory brain tumours. Cohorts of 3-6 patients were treated for 42 d, followed by a 7-d rest period for a maximum of 6 cycles. Patients were stratified as heavily pre-treated (HPT) and non-heavily pre-treated (NHPT). Starting doses were 50 mg/m2 (HPT) or 75 mg/m2 (NHPT). Out of 28 patients enrolled, 20 were evaluable for toxicity and 19 for pharmacokinetics. Three patients in the NHPT group developed grade 3/4 haematological toxicity, 2 experienced dose-limiting toxicity (thrombocytopenia) at 100 mg/m2, and 9/20 developed grade 3 lymphopenia. MTD in both strata was 85 mg/m2. Responses were observed in 4 patients: 2 complete responses (CR) in medulloblastoma and supratentorial primitive neuroectodermal tumours (PNET), and 2 partial responses (PR) in high-grade glioma, respectively. Overall cumulative exposure was at least 1.5 times higher than in the 5-d administration schedule. In conclusion, the recommended dose of temozolomide is 85 mg/m2 x 42 d. Dose-limiting toxicities are thrombocytopenia and lymphopenia. The observed response rate warrants phase II studies.

Outcome of clear cell sarcoma of the kidney (CCSK) treated on the National Wilms Tumor Study-5 (NWTS)

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Background: CCSK was initially described by its bone metastasizing tendencies and propensity for late recurrences. Outcome for patients with CCSK has improved from NWTS 1–4. On NWTS 4 patients were randomized to treatment for 15 months vs 6 months. Their overall 8 year relapse free survival was 88% vs 61%, respectively. NWTS-5 was designed to improve the event free survival (EFS) and overall survival (S) for patients with CCSK by incorporating cyclophosphamide and etoposide. Methods: Prospective single-arm study conducted between August, 1995 and June, 2002. Patients less than 16 years of age with a centrally confirmed pathological diagnosis of CCSK were eligible. Staging consisted of CT scans of chest, abdomen, pelvis, bone scan, skeletal survey, and CT or MRI of head. Patients were treated with vincristine/doxorubicin/cyclophosphamide alternating with cyclophosphamide/etoposide for 24 weeks and XRT (10.8 cGy). Results: 110 eligible patients were enrolled on study. Median age was 22 months, 69% were males, and 63% white. Stage distribution was: stage I, 14; II, 41; III, 46; IV, 9 [metastatic sites: lung (3), bone (1), brain (1), liver (1), bone and bilateral lung (1) and other (2)] Median follow-up is 4.6 years. 5-year EFS and S were 79% (95% CI, 69% to 86%) and 89% (95% CI, 80% to 94%). All but one of 21 recurrences occurred within 3 years of initial treatment. The most common site of recurrence was brain (11/21). 5-year EFS for Stage I-IV was 100%, 87%, 74% and 36% respectively. Adverse prognostic factors for patients with Stage II/III disease were white race, and lymph node involvement. Conclusions: Outcome for patients with CCSK treated on NWTS-5 is similar to that seen on NWTS-4 and recent SIOP and UKCCSG trials. Stage is highly predictive of outcome. Brain recurrence was higher than that seen on NWTS-4; lung recurrences were lower. The next Childrens Oncology Group (COG) protocol will use the same treatment for patients with Stages I-III; therapy for patients with Stage IV disease will incorporate carboplatin. The role of XRT in CCSK needs to be evaluated.

No significant financial relationships to disclose.

Choroid plexus tumours

Choroid plexus tumours are rare epithelial brain tumours and limited information is available regarding their biology and the best treatment. A meta-analysis was done to determine prognostic factors and the influence of various treatment modalities. A thorough review of the medical literature (1966-1998) revealed 566 well-documented choroid plexus tumours. These were entered into a database, which was analysed to determine prognostic factors and treatment modalities. Most patients with a supratentorial tumour were children, while the most common sites in adults were the fourth ventricle and the cerebellar pontine angle. Cerebellar pontine angle tumours were more frequently benign. Histology was the most important prognostic factor, as one, five, and 10-year projected survival rates were 90, 81, and 77% in choroid plexus-papilloma (n=353) compared to only 71, 41, and 35% in choroid plexus-carcinoma respectively (P<0.0005). Surgery was prognostically relevant for both choroid plexus-papilloma (P=0.0005) and choroid plexus-carcinoma (P=0.0001). Radiotherapy was associated with significantly better survival in choroid plexus-carcinomas. Eight of 22 documented choroid plexus-carcinomas responded to chemotherapy. Relapse after primary treatment was a poor prognostic factor in choroid plexus-carcinoma patients but not in choroid plexus-papilloma patients. Treatment of choroid plexus tumours should start with radical surgical resection. This should be followed by adjuvant treatment in case of choroid plexus-carcinoma, and a "wait and see" approach in choroid plexus-papilloma.

Treatment with nephrectomy only for small, stage I/favorable histology Wilms' tumor: a report from the National Wilms' Tumor Study Group

PURPOSE

Children younger than 24 months with small (< 550 g), favorable histology (FH) Wilms tumors (WTs) were shown in a pilot study to have an excellent prognosis when treated with nephrectomy only.

PATIENTS AND METHODS

A study of nephrectomy only for the treatment of selected children with FH WT was undertaken. Stringent stopping rules were designed to insure closure of the study if the true 2-year relapse-free survival rate was 90% or lower.

RESULTS

Seventy-five previously untreated children younger than 24 months with stage I/FH WTs for which the surgical specimen weighed less than 550 g were treated with nephrectomy only. Three patients developed metachronous, contralateral WT 1.1, 1.4, and 2.3 years after nephrectomy, and eight patients relapsed 0.3 to 1.05 years after diagnosis (median, 0.4 years; mean, 0.51 years). The sites of relapse were lung (n = 5) and operative bed (n = 3). The 2-year disease-free (relapse and metachronous contralateral WT) survival rate was 86.5%. The 2-year survival rate is 100% with a median follow-up of 2.84 years. The 2-year disease-free survival rate (excluding metachronous contralateral WT) was 89.2%, and the 2-year cumulative risk of metachronous contralateral WT was 3.1%.

CONCLUSION

Children younger than 24 months treated with nephrectomy only for a stage I/FH WT that weighed less than 550 g had a risk of relapse, including the development of metachronous contralateral WT, of 13.5% 2 years after diagnosis. All patients who experienced relapse on this trial are alive at this time. This approach will be re-evaluated in a clinical trial using a less conservative stopping rule.

Adaptation of renal function after unilateral nephrectomy in children with renal tumors

Following treatment, survivors of unilateral Wilms tumor (WT) develop structural and functional changes in the remnant kidney. A disproportional increase in functional over structural changes results in hyperfiltration, a condition that may lead to renal damage. We studied adaptation of renal function after uninephrectomy in ten WT patients and a child with renal cell carcinoma. Glomerular filtration rate (GFR) (measured by inulin and creatinine clearances), renal plasma flow (RPF) by para-aminohippurate (PAH) clearances and segmental tubular Na+ transport were studied before and following a protein load (renal functional reserve). Nine patients showed a well-adapted kidney function with a GFR of 82.27 (+/- 5.6), an RPF of 429.71 (+/- 65.6) ml/min/1.73 m2 and a filtration fracton (FF) of 20%. Absolute proximal Na+ reabsorption was 65.2 (+/- 9.6) ml/min/1.73 m2, distal tubular delivery was 18.2 (+/- 3.9) ml/min/1.73 m2 and absolute distal Na+ reabsorption was 2146 (+/- 435) microM/min. A peculiar finding was the high baseline creatinine clearances (176.17 ml/min/1.73 m2) related to increased baseline tubular creatinine secretion. Over 120 min following the protein load, GFR increased by 20%, RPF by 6% and FF remained unchanged. Absolute proximal reabsorption increased by 20% and distal reabsorption by 22%. While most changes in renal function induced by a protein load are similar in healthy individuals and uninephrectomized patients, a more predominant contribution to Na+ reabsorption by the proximal tubule was noted. Postload fractional proximal reabsorption remained at 77% while in healthy persons a decrease from 77% to 62% was reported. Two patients showed dysfunctional changes following nephrectomy characterized by an increased GFR (130 ml/min/1.73 m2), increased filtration fraction (29%) and inability to increase glomerular and tubular functions following a protein load (loss of functional reserve). The significance of these abnormalities is not known and requires long-term follow-up to evaluate whether hyperfiltration will lead to renal damage.

Hematopoietic stem cell transplantation (HSCT) with a conditioning regimen of busulfan, cyclophosphamide, and etoposide for children with acute myelogenous leukemia (AML): a phase I study of the Pediatric Blood and Marrow Transplant Consortium

BACKGROUND

Hematopoietic stem cell transplantation (HSCT) is an important treatment modality for children with AML. The optimal conditioning regimen is unknown. The aim of this study was to determine the appropriate dosing of etoposide in combination with busulfan and cyclophosphamide in this setting.

PROCEDURE

Twenty patients with a diagnosis of AML in first or second remission, or myelodysplasia scheduled for bone marrow transplantation, were included in this study. Patients received busulfan 640 mg/m(2) in 16 doses, cyclophosphamide 120 to 150 mg/kg in two doses, and etoposide from 40-60 mg/kg as a single dose. Extensive toxicity data was collected.

RESULTS

Nineteen patients were evaluable for toxicity. Mucositis was seen in all patients. Four patients developed bacteremia and one patient died from overwhelming sepsis on day +3. Four patients developed moderate to severe skin toxicity. The major dose-limiting +3 toxicity was hepatic toxicity, which occurred in 14 of 19 patients. Eight patients developed clinical veno-occlusive disease, including three patients at dose level 4, two of whom had life-threatening disease. This hepatic toxicity defined the MTD of 640 mg/m(2) busulfan, 120 mg/kg of cyclophosphamide, and 60 mg/kg of etoposide. Overall, 9 of 20 patients enrolled in the study survive in remission, 8/14 allogeneic (median follow-up 44 months), and one of six autologous patients (follow-up, 54 months).

CONCLUSIONS

We conclude that the combination of busulfan, cyclophosphamide, and etoposide at the doses defined above has activity in the treatment of children with high-risk AML/MDS undergoing allogeneic HSCT. Whether it offers an advantage over other conditioning regimens will require a randomized trial with a larger cohort of patients.

Decreased expression of the INK4 family of cyclin-dependent kinase inhibitors in Wilms tumor

Cyclin-dependent kinase (CDK) inhibitors represented by the INK4 family (including p16(INK4a, CDKN2A), p15(INK4b, CDKN2B), p18(INK4c, CDKN2C), and p19(INK4d, CDKN2D)) are regulators of the cell cycle shown to be aberrant in many types of human cancer. We tested the hypothesis that these CDK inhibitors are a target for altered gene expression in Wilms tumor. Using RT-PCR, gene expression of the INK4 family was found to be decreased in 9 of 38 Wilms tumor samples obtained from the National Wilms Tumor Study Group (NWTSG) tissue bank. All the affected tumor samples were of favorable histology. Methylation-specific PCR revealed that methylation in the p16 promoter region may be responsible for altered expression. The incidence of loss of p16 expression may increase with increasing tumor stage, i.e., 1/10 (10%) with stage I/II FH Wilms tumor, 2/10 (20%) with stage III FH Wilms tumor, and 4/10 (40%) with stage IV FH Wilms tumor. Thus, determining the expression status of the INK4 family may have potential prognostic value in the management of Wilms tumor.

Principles of Wilms' tumor biology

The last few years have provided dramatic breakthroughs in understanding the genetic factors involved in Wilms' tumorigenesis and normal kidney development. The implications of these findings for the clinical management of children with Wilms' tumor are only now becoming apparent. Over 80% of patients with Wilms' tumor can be cured using contemporary multimodality therapy. As a consequence, the current NWTSG is attempting to intensify treatment for patients with poor prognostic features while decreasing therapy, and thereby adverse late effects, for patients with favorable prognosticators.

Further evidence for genetic heterogeneity in familial hemophagocytic lymphohistiocytosis (FHLH)

Familial hemophagocytic lymphohistiocytosis (FHLH; MIM #267700) is an autosomal recessive disorder of immune regulation characterized by fever, hepatosplenomegaly, and cytopenia that is fatal without bone marrow transplantation. Recent studies have suggested the existence of FHLH loci at 9q21.3-22 and t0q21-22 in Asian and European/African/Australian families, respectively. We studied two unrelated Canadian families in which first cousins were affected with FHLH. In an effort to localize the causative gene, we completed a genome-wide screen for homozygosity by descent by using an automated system to genotype 400 highly polymorphic dinucleotide repeat markers covering the genome with an average resolution of 10 centiMorgans (cM). We identified a total of three candidate loci that met the combined criteria for homozygosity by descent in one family and shared maternal alleles in the other family. One of these, D9S1690, had a cytogenetic localization (9q22.33) proximal to a previously reported inversion of chromosome 9 in an FHLH patient. However, additional closely linked flanking markers within 1-2 cM of all three candidates did not conform to the criteria for linkage in either family. Similarly, we excluded the linked 9q21.3-q22 and 10q21-22 regions recently reported in Asian and European/African/Australian families, respectively. The two families were then analyzed independently to encompass the possibility that they were segregating separate genes. Six additional candidate loci were identified on the basis of homozygosity for the same allele in all affected members of one family, but further analysis of closely linked flanking markers did not demonstrate similar homozygosity. Our data provide further evidence of genetic heterogeneity in FHLH and suggest the existence of at least a third locus for this disease.

Early outcomes after allogeneic stem cell transplantation for leukemia and myelodysplasia without protective isolation: a 10-year experience

Although it is common practice to use some form of isolation to protect allogeneic stem cell transplant patients from infection, the necessity for these practices in all environments has not been demonstrated. The current study evaluated patterns of infection and 100-day transplant-related mortality in 288 patients with myelodysplasia and leukemia transplanted without isolation. Patients were allowed out of hospital at any time within constraints of the medication schedule. Fever, foci of infection, and positive cultures within 28 days and death within 100 days because of the transplant procedure were recorded. Fever occurred in 57% of patients, and 10% had a clinical or radiographic focus of infection. Most infections were apparently endogenous; blood cultures from 24% of recipients grew organisms, 87% of which were gram-positive bacteria. Four patients (1%) died with aspergillus infection in circumstances indicating that isolation would not have been helpful. Twenty percent of patients remained without evidence of infection throughout. Transplant-related mortality at 100 days was 1% for 108 patients with early leukemia receiving transplants from matched siblings. For patients at higher risk, by virtue of donor and/or disease status, mortality was 21%. These figures compare favorably with those reported to the International Bone Marrow Transplant Registry, the majority of patients having been subjected to some form of isolation. We conclude that allogeneic stem cell transplantation can be safely performed in some environments without confining patients continuously to the hospital.

Allogeneic blood stem cell and bone marrow transplantation for acute myelogenous leukemia and myelodysplasia: influence of stem cell source on outcome

We have compared the outcomes of 87 patients with acute myelogenous leukemia (AML) and myelodysplasia (MDS) receiving matched sibling transplants with stem cells from peripheral blood (blood cell transplant, BCT) or bone marrow (BMT). In good risk patients (AML in CR1) granulocytes recovered to 0.5 x 10(9)/l a median of 14 days after BCT compared with 19 days after BMT (P < 0.0001). For patients with poor risk disease (AML beyond CR1 and MDS) corresponding figures were 16 vs 26 days (P < 0.0001). Platelet recovery to 20 x 10(9)/l was also faster after BCT (good risk 12 vs 20 days, P < 0.0001; poor risk 17 vs 22 days, P = 0.04). Red cell transfusions were unaffected by cell source, but BCT recipients required less platelet transfusions (good risk 1 vs 5, P = 0.002; poor risk 5 vs 11, P = 0.004). Blood cell transplants resulted in more chronic GVHD (86% vs 48%, P = 0.005) and a significantly higher proportion of recipients with KPS of 80% or less (48% vs 5%, P = 0.004). Disease-free survival at 4 years was 23% for both groups of poor risk patients but outcome in good risk patients was better after BCT (93% vs 62%, P = 0.047) related mainly to less relapse. While disease-free survival may be better after BCT than BMT for AML in CR1, quality of life may be relatively impaired.

Neuropsychologic deficits in children with Langerhans cell histiocytosis

BACKGROUND

Manifestations of Langerhans cell histiocytosis (LCH) in children range from only a rash, to bony lesions accompanied by pain, to major organ disease. When the central nervous system (CNS) is affected, the LCH patient may exhibit signs and symptoms of hypothalamic and pituitary dysfunction (most often resulting in diabetes insipidus or other endocrinopathies) or more global neurologic and neuropsychologic sequelae. Surprisingly, researchers have only recently begun to examine the neuropsychologic manifestations of the disease, but early findings suggest that they may, in fact, be significant in a small percentage of children with LCH.

PROCEDURE

We evaluated two CNS-positive patients with LCH and long-term intermittent treatments, using extensive neuropsychologic assessments, including intellectual functioning, memory, visual-motor functioning, attention and concentration, sensory and motor performance, and gross academic achievement. Objective measures of behavior were obtained through parental report. Neuroradiologic imaging was obtained concurrently with the neuropsychologic evaluations.

RESULTS

The neuropsychologic assessments indicated significant deficits in a number of the measured areas of functioning. Global cognitive deficiencies in full-scale IQ were identified, as were deficits in memory, attention/concentration, and perceptual-organizational capabilities. Similarities were noted in the patterns of deficits obtained with both patients, despite differences in the pathophysiology of their disease. Behavioral functioning in both children had suffered, presumably in relation to the neuropsychologic deficits. There were radiologic findings of gross cerebellar white matter damage in one patient, in addition to focal (e.g., hypothalamic) lesions in the other.

CONCLUSIONS

LCH has an adverse impact on cognitive functions in some children with evidence of CNS involvement, and further study into the etiology, incidence, and means of remedial intervention is needed.

Wilms tumour: diagnosis and treatment

Wilms tumour is the most common intra-abdominal solid tumour of childhood. Treatment includes surgical resection and chemotherapy for virtually all affected children and additional radiotherapy for those with advanced disease or adverse prognostic features. This approach leads to cure rates exceeding 80%. During the last decade there have been a number of advances which have increased our understanding of the biology of Wilms tumour. The development of Wilms tumour, for example, involves several genes, including WT1, the Wilms tumour suppressor gene at 11p13, and WT2, the putative Wilms tumour suppressor gene at 11p15. In addition, certain chromosomal regions, most notably 16q and 1p, might predict outcome and hence serve as a prognostic factor, useful for determining the intensity of therapy. This novel information is now being incorporated into current therapeutic protocols. We reviewed the medical literature and present a summary of the advances made, outlining the current treatment of Wilms tumour. Future protocols will continue incorporating biological markers. The goal is to identify patients at low risk for relapse, which will allow a reduction in treatment intensity and subsequent toxicity. Children at an increased risk for relapse can be selected for more intensive treatment.

Open-label comparison of the antiemetic efficacy of single intravenous doses of dolasetron mesylate in pediatric cancer patients receiving moderately to highly emetogenic chemotherapy

BACKGROUND

Nausea and vomiting are among the most unpleasant adverse side effects of cancer therapy.

PROCEDURE

An open-label dose-escalation study was conducted to assess the appropriate intravenous dose of dolasetron for pediatric patients undergoing chemotherapy. Patients received dolasetron in single intravenous doses of 0.6 (n = 10), 1.2 (n = 12), 1.8 (n = 12), or 2.4 (n = 12) mg/kg 30 min before receiving emetogenic chemotherapy. Pharmacokinetic parameters were evaluated at each dose level and efficacy was evaluated over the first 24 hr following the administration of dolasetron.

RESULTS

A complete response was achieved in 10% of patients given 0.6 mg/kg, 25% of patients given 1. 2 mg/kg, 67% of patients given 1.8 mg/kg, and 33% of patients given 2.4 mg/kg. Peak plasma concentrations (Cmax) were observed between 0. 33 and 0.75 hr following dolasetron infusion. Cmax and area under plasma concentration-time (AUC) increased with larger doses of dolasetron, while terminal disposition half-life (t1/2) and apparent clearance (Clapp) were not significantly changed with respect to dose. For 1.8-mg/kg dolasetron, the t1/2 was 4.98 hr and the maximum plasma concentration (tmax) 0.47 hr. Adverse events were mild to moderate. No serious events occurred. Conclusions. This study suggests that a single intravenous dose of 1.8 mg/kg is the optimum single intravenous dose for controlling chemotherapy-induced emesis in pediatric patients.

Safety, tolerability, antiemetic efficacy, and pharmacokinetics of oral dolasetron mesylate in pediatric cancer patients receiving moderately to highly emetogenic chemotherapy

PURPOSE

The safety, antiemetic efficacy, and pharmacokinetics of single oral doses of dolasetron, a new highly selective 5-HT3 receptor antagonist, were evaluated in children with cancer undergoing treatment with moderately to highly emetogenic chemotherapy.

PATIENTS AND METHODS

A total of 32 children, ages 3 to 18 years, were enrolled in a nonrandomized, multicenter, open-label, dose-escalation study. Three oral dose levels (0.6, 1.2, or 1.8 mg/kg) were studied. Safety, efficacy, and pharmacokinetic parameters were assessed over 24 hours at each dosage level.

RESULTS

The most effective dose was 1.8 mg/kg; 60% of the patients achieved a complete or major response (< or =2 emetic episodes in 24 hours). A complete response was achieved in 3 of 9 patients (33%) who received 0.6 mg/kg, 4 of 13 (31%) patients who received 1.2 mg/kg, and 5 of 10 (50%) patients who received 1.8 mg/kg of dolasetron. Overall, dolasetron was well tolerated. Adverse events were mild and similar to those reported in adults. Peak plasma concentrations (Cmax) of dolasetron's active reduced metabolite, MDL 74,156, were dose proportional and occurred, on the average, within 1 hour of oral administration. The half-life (t1/2) in plasma was approximately 6 hours for all dose levels, and the mean clearance (CLapp) was unrelated to dose.

CONCLUSIONS

Oral dolasetron is safe and effective in reducing chemotherapy-induced nausea and vomiting, particularly at the 1.8-mg/kg dose level. These results support further evaluation of oral dolasetron in larger randomized clinical trials in the pediatric cancer population.

Factors affecting the risk of contralateral Wilms tumor development: a report from the National Wilms Tumor Study Group

BACKGROUND

Approximately 1% of children with unilateral Wilms tumor develop contralateral disease. The authors assessed the demographic and histologic features associated with metachronous bilateral Wilms tumor (BWT).

METHODS

Characteristics of all children registered on the first four National Wilms Tumor Studies (NWTS) were recorded. The primary endpoint for evaluation was the first appearance of Wilms tumor in the remaining kidney. The cumulative risk of contralateral disease as a function of time since initial presentation was calculated as 1 minus the Kaplan-Meier estimate of remaining free of contralateral disease. A matched case control study was conducted to determine whether the presence and type of nephrogenic rests (NRs) were associated with metachronous BWT.

RESULTS

Fifty-eight of 4669 registered children developed metachronous BWT; 38 of 2445 females (expected, 30.2) versus 20 of 2224 males (expected, 27.8) (P = 0.04) developed BWT. The cumulative incidence of contralateral disease 6 years after initial diagnosis decreased from greater than 3% in the first NWTS to approximately 1.5% in the three subsequent studies (P = 0.08). Patients with NRs had a significantly increased risk of metachronous BWT. This was particularly true for young children (20 of 206 age < 12 months compared with 0 of 304 age > 12 months). Data from the matched case control study confirmed the increased relative risk associated with young age and the presence of NRs.

CONCLUSIONS

Children younger than 12 months diagnosed with Wilms tumor who also have NRs, in particular perilobar NRs, have a markedly increased risk of developing contralateral disease and require frequent and regular surveillance for several years. Surveillance is also recommended for those with NRs who are diagnosed after the age of 12 months.

Long-term complications and post-treatment follow-up of patients with Wilms' tumor

An increasing number of children with Wilms' tumor can expect to be cured, reflecting the undisputed progress made in the treatment of children with this renal cancer. However, it does underscore the need to screen survivors for late effects of cancer therapy. Some of the late effects, such as those following radiation therapy, should be expected after a considerable latent period. Others, such as those occurring after the administration of certain chemotherapeutics agents, are commonly immediate, usually transient, but occasionally permanent. Although children seem to tolerate acute toxicities of therapy better than do adults, the growing child may be more vulnerable to the delayed adverse sequelae of cancer therapy, such as effects on growth, fertility, and neuropsychological function. This article reviews many of the late effects seen in survivors of Wilms' tumor and the way in which these effects relate to the different therapeutical modalities used (surgery, chemotherapy, and radiation).

Genetics of Wilms' tumor

The molecular genetic characterization of Wilms' tumor has played a prominent role in advancing our knowledge of the genetic aspects underlying the development of cancer in general. Unlike the genetic mechanism leading to the development of retinoblastoma, an embryonal tumor of childhood affecting the retina, which only requires the inactivation of one single gene, the biological pathways leading to the development of Wilms' tumor are complex and likely involve several genetic loci. These include two genes on chromosome 11p; one on chromosome 11p13 (the Wilms' tumor suppressor gene WT1) and the other on chromosome 11p15 (the putative Wilms' tumor suppressor gene WT2). In addition to these two genes, loci at 1p, 7p, 16q, 17p (the p53 tumor suppressor gene), and 19q (the putative familial Wilms' tumor gene FWT2) are also believed to harbor genes involved in the biology of Wilms' tumor. Herein these loci are reviewed and their clinical significance is summarized.

Mesna inactivates platinum agents in vitro

BACKGROUND

Platinum agents are frequently combined with ifosfamide. Mesna, originally coadministered to protect from ifosfamide side effects, might also react with the platinum agents in these combinations.

METHODS

Malignant glioma cells were incubated with cisplatin, carboplatin and mesna. Cell numbers were measured by counting and by MTT-tests.

RESULTS

In cell free solution mesna turned MTT to its blue farmazan product. Mesna's effect on cells were cell-line specific: It penetrated U87 cells without effect on growth, reduced cell numbers in C6 and T98G cells and did not alter U251 cells. The concentration of cisplatin killing 50% of the cells were 7 x 10(-7) in C6, 9.7 x 10(-6) in T98G, 1.2 x 10(-5) in U251 and 2.4 x 10(-4) in U87 cells. For the same effect, carboplatin required 3-10 times higher concentrations. Mesna protected all cell lines from the cytotoxicity of the platinum agents.

CONCLUSION

Clinical studies should specify in detail, infusion schedules of mesna and platinum agents.

Current concepts in the biology and management of Wilms tumor

PURPOSE

There have been a number of advances that have increased our understanding of the biology of Wilms tumor during the last decade. This information is now being incorporated into current pediatric oncology protocols. We present a summary of these advances and outline the current treatment of Wilms tumor.

MATERIALS AND METHODS

The medical literature was reviewed with an emphasis on the molecular biology of Wilms tumor.

RESULTS

The development of Wilms tumor involves several genes, including WT1, the Wilms tumor suppressor gene at 11p13. In addition, certain chromosomal regions (16q and 1p) might be used as prognostic factors for determining the intensity of therapy.

CONCLUSIONS

Future protocols conducted by pediatric oncology groups will incorporate biological studies. The goal is to identify patients at low risk for relapse which will allow a reduction in treatment intensity and subsequent toxicity. Children at an increased risk for relapse can be selected for more intensive treatment.

Fractionated cylophosphamide and back to back high dose methotrexate and cytosine arabinoside improves outcome in patients with stage III high grade small non-cleaved cell lymphomas (SNCCL): a randomized trial of the Pediatric Oncology Group

BACKGROUND

The Pediatric Oncology Group (POG) conducted a two-arm, randomized study for the treatment of children and adolescents with stage III small, non-cleaved cell lymphoma (SNCCL). Regimen A, based on the group's previous best treatment for this group of patients, included cyclophosphamide (CTX) and high-dose methotrexate (MTX), as well as vincristine (VCR), prednisone (PRED), and intrathecal (IT) chemoprophylaxis. Regimen B, based on a single institution pilot study (Total B therapy), consisted of two rapidly alternating chemotherapy combinations (CTX, VCR, doxorubicin; MTX, and cytarabine (Ara-C) plus coordinated IT chemotherapy.

PROCEDURE

One hundred thirty-four consecutive patients were entered on this study. Seventy patients were randomized to Regimen A, and 64 patients to Regimen B. One hundred and twenty-two patients are eligible for response.

RESULTS

Complete remission (CR) was achieved by 81% (52/64) of patients on Regimen A, and 95% (55/58) of patients on Regimen B (p=0.014 one-sided). The two-year event-free survival (EFS) is 64% (SE=6%) on Regimen A, and 79% (SE=6%) on Regimen B (p=0.027 by one-sided logrank test). No patient has relapsed on either regimen after a year from diagnosis, although one patient had a second malignancy at day 371. Severe, but manageable, hematologic toxicity was seen in the majority of patients on both regimens, but was more frequent on Regimen B.

CONCLUSIONS

We conclude that the cure rate in stage III SNCCL is significantly improved with the use of a short, six-month chemotherapy regimen of fractionated CTX alternated with coordinated MTX and Ara-C. Results suggest that drug schedule, not simple drug selection, influences outcome.

Cutaneous toxicity following the administration of dactinomycin

Dactinomycin (AMD) is an effective drug in the management of several malignant disorders and has been used for almost 40 years. Skin and subcutaneous toxicities following extravasation are well known and can be harmful. Similarly radiation-recall is a well established phenomenon following the administration of AMD. We report a patient who developed a localized brawny erythema in the crural folds and the axillae, likely due to AMD. This rare skin complication of AMD seems to benefit from topical corticosteroid treatment, although postinflammatory hyperpigmentation may take months to disappear.

Partially mismatched blood cell transplants for high-risk hematologic malignancy

Eleven patients with high-risk hematologic malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from partially mismatched family members in whom progenitor cells had been mobilized by G-CSF. Donors were mismatched by up to one antigen in the GVH direction and up to three antigens in the rejection direction. Outcomes were compared with those of 22 patients receiving BCT from fully matched donors. Two mismatched patients died without engraftment on day 21 and 32. One had rejected bone marrow from the same donor, the other was mismatched by two antigens in the rejection direction and received the lowest dose of CD34+ cells. Median time to granulocyte engraftment was 21.5 (range 16-33) days for the mismatched group compared with 16 (11-28) days for the matched group (P = 0.01). No correlation was found between CD34+ cell dose and time to granulocyte or platelet recovery. In the mismatched and matched BCT groups respectively, the risk of grade II-IV acute graft-versus-host disease (GVHD) was 73% vs 28% (P = 0.001) and of chronic GVHD 100% vs 78% at 18 months (P = 0.01). The relationship of T cell dose to acute GVHD could only be evaluated in the matched group and no correlation was found. One of 11 mismatched patients and eight of 22 matched patients had relapse or persistent disease. Disease-free survival at 1 year was similar at 55% for mismatched and 50% for matched BCT. These results indicate that allogeneic BCT from partially mismatched family members is accompanied by a high incidence of GVHD but may result in comparable survival to BCT from fully matched donors.

Metastatic renal cell carcinoma in a child: 11-year disease-free survival following surgery

A child with metastatic renal cell carcinoma (RCC) is presented. This case is unusual in that the patient has remained disease free for 11 years following surgery and only one course of chemotherapy prior to thoracotomy. The management of metastatic RCC is reviewed and the genetic mechanisms leading to its development briefly discussed.

Second allogeneic transplants for leukemia using blood instead of bone marrow as a source of hemopoietic cells

There is increasing interest in blood cell transplants (BCT) from normal donors as an alternative to BMT. Ten patients with relapsed or persistent leukemia after BMT received intensive cytotoxic conditioning followed by allogeneic BCT. Three BCT were from single-antigen mismatched donors; two of the corresponding recipients had rejected a BMT from the same donor. Two patients received BCT from a different donor (one matched, one single-antigen mismatched). The other six BCT were from the same, fully matched, bone marrow donors. Donors were given G-CSF to mobilize progenitor cells which were collected by a single 2-4 h leukapheresis. Methotrexate, CsA and folinic acid were used for GVHD prophylaxis for all transplants but CsA was discontinued sooner after BCT than after BMT. One patient died without engraftment having rejected a BMT from the same single-antigen mismatched donor 4 years previously. Nine patients had granulocyte recovery at a median of 14 days, up to 6 days faster than with their previous BMT. Platelet recovery was also 2-6 days faster than with BMT in four previously engrafting patients. Four patients died without platelet recovery after BCT within a year of BMT, three of treatment-related toxicity and one of relapse. Two patients developed grade II acute GVHD. Of six patients given BCT more than a year from BMT, four, all with acute leukemia, survive 7, 14, 29 and 29 months after BCT and one relapsed at 7 months. All four survivors developed chronic GVHD. These results indicate that BCT may be useful therapy for relapse occurring more than a year after BMT.

Allogeneic blood cell transplants for haematological malignancy: preliminary comparison of outcomes with bone marrow transplantation

Twenty-six patients with haematological malignancy received cryopreserved but otherwise unmanipulated blood cell transplants (BCT) from five- or six-antigen matched siblings in whom progenitor cells had been mobilized by G-CSF. Outcomes were compared with a historical control group of 26 BMT patients matched for age and disease status. Granulocyte counts recovered to 0.5 x 10(9)/l in a median of 16 days after BCT compared with 21.5 days after BMT (P = 0.0002). Platelet counts, unsupported for 3 days, reached 20 x 10(9)/l in a median of 14 days vs 20.5 days (P = 0.0003) after BCT compared with BMT in those patients who engrafted. In the BCT and BMT groups, respectively, the risk of grade II-IV acute GVHD was 37 vs 21% (P = 0.16) and of chronic GVHD at 1 year 53 vs 48% (P = 0.9). There was no significant difference in red cell transfusions but BCT patients required fewer platelet transfusions (median 3 vs 5, P = 0.015) and fewer days in hospital (20.5 vs 25, P = 0.02). These results indicate that allogeneic BCT from matched and partially mismatched family donors result in faster engraftment than BMT without a significant increase in GVHD. Allogeneic BCT may prove to be a more tolerable procedure than BMT for both donor and recipient and there are indications of improved cost-effectiveness.

Future directions in clinical research in Wilms tumor

The national and international cooperative study groups have provided the scientific and administrative framework for the evaluation of various treatment regimens in patients with Wilms tumor. These have yielded excellent overall survival rates while identifying prognostic factors that have permitted modulation of therapy according to well-documented risk indices. Thus, they have demonstrated that treatments associated with important acute or long-term morbidities or both are not necessary for such patients as those with NWTS stage I or II, favorable histology Wilms tumor. It is now time to move beyond the traditional randomized prospective clinical trial method, which is not suitable to the attainment of remaining goals. Attempts to decrease the intensity of treatment even more in the future will be based on stratification of patients according to the presence or absence of one or more sensitive biologic prognostic factors. Such "markers," it is to be hoped, will make it possible to eliminate cardiotoxic and nephrotoxic drugs from the treatment of all but those at high risk of relapse.