Treatment of high-risk neuroblastoma with intensive chemotherapy, radiotherapy, autologous bone marrow transplantation, and 13-cis-retinoic acid. Children's Cancer Group

Pulmonary metastases at diagnosis of neuroblastoma in pediatric patients: CT findings and prognosis

OBJECTIVE

We undertook this study to determine the frequency, CT appearance, and clinical implications of the rare occurrence of pulmonary metastases among children presenting with neuroblastoma.

MATERIALS AND METHODS

A search of the Children's Cancer Group database revealed 21 of 567 children with reported lung metastases at original diagnosis of neuroblastoma. CT examinations available for 17 of these patients were analyzed retrospectively to determine if lung metastases were present, and if so, to characterize their radiographic features.

RESULTS

Seventeen (3%) of 567 patients presenting with Evans stage IV neuroblastoma had confirmed pulmonary metastases at diagnosis. All had metastases to at least one site other than the lungs. The most common CT appearance of pulmonary lesions was of up to five, small, bilateral, noncalcified nodules. In nine patients (53%), the pulmonary nodules initially resolved with treatment. In this cohort, six children developed progressive disease and died, and three are still alive. All eight children whose lung lesion did not completely respond to treatment died. Overall, children with pulmonary metastases had unfavorable Shimada histology, a higher association with amplification of the MYCN oncogene (p = 0.0002), and a decreased event-free survival (p < 0.001) when compared with all children with stage IV neuroblastoma without pulmonary metastases.

CONCLUSION

The search for neuroblastoma lung metastases, which occur more frequently than previously reported, is clinically important because their presence portends a poor prognosis.

Comparative genomic hybridization (CGH) analysis of stage 4 neuroblastoma reveals high frequency of 11q deletion in tumors lacking MYCN amplification

We have studied the occurrence and association of 11q deletions with other chromosomal imbalances in Stage 4 neuroblastomas. To this purpose we have performed comparative genomic hybridization (CGH) analysis on 50 Stage 4 neuroblastomas and these data were analyzed together with those from 33 previously published cases. We observed a high incidence of 11q deletion in Stage 4 neuroblastoma without MYCN amplification (59%) whereas 11q loss was only observed in 15% of neuroblastomas with MYCN-amplification (p = 0.0002) or 11% of cases with 1p deletion detected by CGH (p = 0.0001). In addition, 11q loss showed significant positive correlation with 3p loss (p = 0.0002). Event-free survival was poor and not significantly different for patients with or without 11q deletion. Our study provides further evidence that Stage 4 neuroblastomas with 11q deletions represent a distinct genetic subgroup that typically shows no MYCN-amplification nor 1p deletion. Moreover, it shows that neuroblastomas with 11q deletion also often present 3p deletion. This genetic subgroup shows a similar poor prognosis as MYCN amplified 4 neuroblastomas.

Megatherapy combining I(131) metaiodobenzylguanidine and high-dose chemotherapy with haematopoietic progenitor cell rescue for neuroblastoma

Despite the use of aggressive chemotherapy, stage 4 high risk neuroblastoma still has very poor prognosis which is estimated at 25%. Metabolic radiotherapy with I(131) MIBG appears a feasible option to enhance the effects of chemotherapy. Seventeen patients having MIBG-positive residual disease received 4.1-11.1 mCi/kg of I(131) MIBG 7-10 days before initiating the high-dose chemotherapy cycle consisting of busulphan 16 mg/kg and melphalan 140 mg/m(2) followed by PBSC infusion. We compared the toxicity in these patients to that seen in 15 control subjects with neuroblastoma who underwent a PBSC transplant without MIBG therapy. We observed greater toxic involvement of the gastrointestinal system in children treated with I(131) MIBG: grade 2 or 3 mucositis developed in 13/17 patients treated with I(131) MIBG and in 9/15 treated without it. Grade 1-2 gastrointestinal toxicity occurred in 12/17 children given MIBG and in 5/15 of the controls. One child receiving I(131) MIBG developed transient interstitial pneumonia. Another child who also received I(131) MIBG after PBSC rescue developed fatal pneumonia after the third course of metabolic radiotherapy. Our experience indicates that MIBG can be included in the high-dose chemotherapy regimens followed by PBSC rescue for children with residual neuroblastoma taking up MIBG. Attention should be paid to avoiding lung complications. Prospective studies are needed to demonstrate the real efficacy of this treatment.

The retinoids and cancer prevention mechanisms

Carcinogenesis is a multistep process that converts normal cells into malignant cells. Once transformed, malignant cells acquire the ability to invade and metastasize, leading to clinically evident disease. During this continuum from normal to metastatic cells, carcinogenic steps can be arrested or reversed through pharmacological treatments, known as cancer chemoprevention. Chemoprevention strategies represent therapeutic interventions at early stages of carcinogenesis, before the onset of invasive cancer. Effective chemoprevention should reduce or avoid the clinical consequences of overt malignancies by treating early neoplastic lesions before development of clinically apparent signs or symptoms. Preclinical, clinical, and epidemiological data provide considerable support for cancer chemoprevention as an attractive therapeutic strategy. This clinical approach was validated in the recent tamoxifen randomized trial, demonstrating that a selective estrogen receptor modulator reduces the risk of breast cancer in women at high risk for this malignancy. Derivatives of vitamin A, the retinoids, have reported activity in treating specific premalignant lesions and reducing incidence of second primary tumors in patients with prior head and neck, lung or liver cancers. Whether the retinoids will prevent primary cancers at these sites is not yet known. Notably, a carotenoid (beta-carotene) was shown as inactive in primary prevention of lung cancers in high-risk individuals. This underscores the need for relevant in vitro models to identify pathways signaling chemopreventive effects. These models should assess the activity of candidate chemoprevention agents before the conduct of large and costly prevention trials. An improved understanding of cancer prevention mechanisms should aid in the discovery of new therapeutic targets and chemoprevention agents. Ideally, these agents should have tolerable clinical toxicities suitable for chronic administration to individuals at high risk for developing primary or second cancers. This article reviews what is now known from clinical and preclinical studies about the retinoids as cancer prevention agents.

Neuroblastomas of infancy exhibit a characteristic ganglioside pattern

BACKGROUND

Gangliosides are membrane-bound glycolipid molecules particularly prominent in neural tissue. Changes in ganglioside expression during embryologic development result from a shift in biosynthesis from the fetal b pathway to the adult a pathway. Tumor gangliosides may play a role in the clinical behavior of certain subtypes of neuroblastoma. Because neuroblastoma, which presents in infancy, has a different biologic and clinical phenotype than that which presents in older children, the authors determined whether differences in ganglioside biosynthesis exist between these two neuroblastoma subgroups.

METHODS

Sixty-eight tumor specimens (25 diagnosed by screening and 43 diagnosed clinically) were obtained from the Quebec Neuroblastoma Screening Project. Gangliosides were isolated and purified by solvent partitioning, separated by high performance thin-layer chromatography, and quantitated by scanning densitometry. The sum of a and b pathway gangliosides were determined for each tumor.

RESULTS

Gangliosides of the b (fetal) pathway predominated in both screened and clinically diagnosed tumors of patients younger than 1 year of age. Twenty-three of 25 screened patients (92%) and 21 of 23 patients with clinically diagnosed tumors at younger than 1 year of age (91%) had tumor b pathway ganglioside content greater than 60%. In contrast, tumors of only 8 of 20 patients 1 year or older (40%) had b pathway ganglioside predominance. Predominance of b pathway tumor gangliosides correlated with improved outcome. Event free survival was significantly higher among patients with b pathway ganglioside tumor content greater than 60% versus those with b pathway ganglioside tumor content less than 60% (118.1 +/- 3.9 months vs. 69.2 +/- 8.6 months, P < 0.01).

CONCLUSIONS

Fetal patterns of ganglioside biosynthesis predominate in neuroblastoma tumors from patients younger than 1 year of age and adult patterns of ganglioside biosynthesis predominate in tumors from older children, supporting the view that neuroblastoma consists of distinct but overlapping disorders, and that gangliosides may play a biologic role in the clinical differences among these patients.

Treatment of advanced neuroblastoma: feasibility and therapeutic potential of a novel approach combining 131-I-MIBG and multiple drug chemotherapy

Biological and clinical observations suggest that initial marked reduction of resistant clones may be critical in any attempt to improve long-term results in advanced neuroblastoma (NB). The aim of this pilot study is to determine short-term toxicity and efficacy of a new therapeutic model based on the simultaneous use of multiple drug chemotherapy and specific irradiation using 131-I-MIBG. The study population consisted of 21 patients, from 1 to 8 years of age with good 131-I-MIBG uptake. 16 extensively pre-treated patients with refractory or relapsed disease were divided into 2 groups. In Group 1 (9 patients) the basic chemotherapy regimen consisted in cisplatin at the dose of 20 mg/m(2) i.v. per day infused over 2 h, for 4 consecutive days; on day 4 Cy 2 g/m(2) i.v. was administered over 2 h followed by Mesna. Group 2 (7 patients) was treated with basic chemotherapeutic regimen plus VP16 and Vincristine. VP16 at the dose of 50 mg/m(2) i.v. per day was administered as a 24 h infusion on days 1-3; Vincristine 1.5 mg/m(2) i.v. was administered on days 1 and 6. On day 10 a single dose of 131-I-MIBG (200 mCi) with a high specific activity (>1.1 GBq/mg) was administered to both Groups by i.v. infusion over 4-6 hours. A further 5 patients were treated at diagnosis: 2 with the same regimen as Group 1 and 3 with the same as Group 2. The severity of toxicity was graded according to World Health Organization (WHO) criteria. Assessment of tumour response was monitored 4-6 weeks after the beginning of combined therapy (CO-TH). Response was defined according to INSS (International Neuroblastoma Staging System) criteria. No extra-medullary toxicity was observed in any patient. Haematological toxicity was the only toxicity observed and seemed mainly related to chemotherapy. Myelosuppression was mild in the 5 patients treated at diagnosis. No serious infections or significant bleeding problems were observed. In the 16 resistant patients, 12 PR, 1 mixed response and 3 SD were obtained. In the 5 patients treated at diagnosis 2 PR, 1 CR and 2 VGPR were observed. No alteration in 131-I-MIBG uptake was observed after the chemotherapy preceding radio-metabolic treatment. The therapeutic results of this pilot regimen of CO-TH resulted in a high percentage of major response after only a single course in both resistant patients and patients treated at diagnosis. Because of the minimal toxicity observed in patients studied at diagnosis so far, there is room for gradual intensification of the treatment. It is to be hoped that this suggested novel approach may represent an important route of investigation to improve final outcome in patients with advanced NB.

Postirradiation hyperthermia selectively potentiates the merocyanine 540-sensitized photoinactivation of small cell lung cancer cells

Lung cancer has long been considered a disease that might benefit from the dose escalation of radio/chemotherapy afforded by a stem cell transplant. However, the clinical experience with high-dose chemotherapy and autologous bone marrow transplantation in lung cancer has been disappointing, with most trials showing little or no improvement in long-term survival. Unfortunately, lung cancer has a tendency to metastasize to the bone marrow, and lung cancer cells are known to circulate in the peripheral blood. Therefore, there is concern that autologous stem cell grafts from lung cancer patients may reinoculate recipients with live tumor cells. Photochemical purging of stem cell grafts with Merocyanine 540 (MC540) is highly effective against a wide range of leukemia and lymphoma cells and is well tolerated by normal hematopoietic stem and progenitor cells. Most solid tumor cells (including lung cancer cells), however, are only moderately sensitive or refractory to MC540-mediated photodynamic therapy (PDT). We report here that postirradiation hyperthermia (< or = 42 degrees C, 3 h) potentiates the MC540-mediated photoinactivation of both wild-type (H69) and cisplatin-resistant mutant (H69/CDDP) small cell lung cancer cells by several orders of magnitude, while only minimally enhancing the depletion of normal human granulocyte/macrophage progenitor cells. Our data suggest that postirradiation hyperthermia provides a simple and effective means of extending the utility of MC540-PDT to the purging of stem cell grafts contaminated with lung cancer and possibly other solid tumor cells.

Disease outcome may be predicted by molecular detection of minimal residual disease in bone marrow in advanced neuroblastoma: a pilot study

PURPOSE

This pilot study focussed on whether sequential molecular detection of minimal residual disease (MRD) in bone marrow (BM) could predict the outcome of patients with advanced neuroblastoma.

PATIENTS AND METHODS

Bone marrow samples from 21 patients older than age 12 months with stage IV neuroblastoma were sequentially examined for tumor cell contamination by detecting tyrosine hydroxylase (TH) messenger ribonucleic acid (mRNA) using reverse transcription-polymerase chain reaction (RT-PCR). Twenty patients received myeloablative therapy with hematopoietic stem cell transplantation after achieving complete remission.

RESULTS

All BM samples of patients except that of one patient was cytologically positive for neuroblastoma cells at diagnosis, and they became negative for neuroblastoma cells within 3 months by cytologic examination. By RT-PCR analysis, BM samples of all patients were positive for TH mRNA at diagnosis, and samples of 19 patients became negative for TH mRNA 1 to 13 months after the start of chemotherapy. Six patients whose BM samples became negative for TH mRNA within 4 months after the start of chemotherapy remained alive without evidence of disease (median 76 mos, range 36-91). In contrast, out of 15 patients whose BM samples remained positive, 10 patients had relapse develop and 9 patients died from disease (median 15 mos, range 10-25). There was a statistically significant difference in disease-free survival between the two groups (P < 0.05).

CONCLUSION

Persistence of MRD in BM may predict poor prognosis in advanced neuroblastoma.

The vitamin A analogues: 13-cis retinoic acid, 9-cis retinoic acid, and Ro 13-6307 inhibit neuroblastoma tumour growth in vivo

BACKGROUND

Neuroblastoma, a childhood tumour of the sympathetic nervous system, may undergo spontaneous differentiation or regression due to apoptosis after no or minimal therapy. However, the majority of neuroblastomas are diagnosed as metastatic tumours with a poor prognosis in spite of intensive multimodal therapy. Vitamin A and its analogues (retinoic acid, RA) play an important role in normal cel lular differentiation and programmed cell death. RA regulates neuroblastoma growth and differentiation in vitro, and has shown activity against human neuroblastoma in vivo.

PROCEDURE

Recently, 9-cis RA was shown to induce apoptosis in vitro in neuroblastoma using a 5 days short-term treatment and subsequent washout. In the present study, nude rats with human neuroblastoma SH-SY5Y xenografts were treated with 13-cis RA (4 mg po daily), 9-cis RA (5 mg po daily) or the novel analogue Ro 13-6307 (0.3 mg po daily) using either a continuous or short-term schedule.

RESULTS

ALL three different retinoids decreased neuroblastoma growth significantly in terms of tumour weight after 8-12 days when compared to untreated controls (P < 0.05). Minor signs of toxicity in 13-cis RA treated rats were observed. However, severe toxicity with significant weight loss was seen in all rats treated with 9-cis RA and Ro 13-6307. Toxicity was more pronounced with the continuous regimen.

CONCLUSIONS

We conclude that different retinoids reduce neuroblastoma tumour growth in vivo. Drug scheduling and dosage may affect both therapeutic efficacy and toxic side effects. Further in vivo studies are warranted, including pharmacokinetic and molecular analyses, before clinical trials with promising retinoids like 9-cis RA and Ro 13-6307 can be started in children with neuroblastoma.

Synergistic induction of apoptosis of neuroblastoma by fenretinide or CD437 in combination with chemotherapeutic drugs

Retinoic acid therapy improves the survival of children with neuroblastoma and 13-cis retinoic acid now forms an important component of treatment for residual disease of stage IV neuroblastoma after chemotherapy. However, although 13-cis retinoic acid induces differentiation, other retinoids are effective at inducing apoptosis of neuroblastoma in vitro, including the novel compounds fenretinide and CD437 and these may be alternative retinoids for neuroblastoma therapy. The aim of our study was to evaluate the ability of fenretinide, CD437 (6-¿3-(1-adamantyl)-4-hydroxyphenyl¿ -2-naphthalene carboxylic acid) and different retinoic acid isomers to induce apoptosis of neuroblastoma in conjunction with the chemotherapeutic drugs, cisplatin, etoposide and carboplatin. Neuroblastoma cell lines were treated with retinoids prior to treatment with chemotherapeutic agents and flow cytometry used to measure apoptosis and free radical generation. Pre-treatment of neuroblastoma cell lines with fenretinide or CD437 prior to treatment with cisplatin, etoposide or carboplatin synergistically increased apoptosis, an effect not seen with 13-cis, all-trans or 9-cis retinoic acid. Contrary to retinoic acid isomers or chemotherapeutic drugs, apoptosis of neuroblastoma cells induced by fenretinide or CD437 was accompanied by the generation of intracellular free radicals. Quenching of fenretinide- or CD437-induced free radicals with antioxidants abolished the synergistic response seen with the subsequent addition of chemotherapeutic agents. Therefore, the generation of free radicals by fenretinide or CD437 may be the key property of these retinoids leading to synergistic responses with chemotherapeutic drugs. Clearly, these synthetic retinoids provide new opportunities for novel neuroblastoma therapy.

Quantitative tumor cell content of bone marrow and blood as a predictor of outcome in stage IV neuroblastoma: a Children's Cancer Group Study

PURPOSE

This study investigated the prognostic value of quantifying tumor cells in bone marrow and blood by immunocytology in children with high-risk, metastatic neuroblastoma.

PATIENTS AND METHODS

Patients with stage IV neuroblastoma (N = 466) registered on Children's Cancer Group study 3891 received five cycles of induction chemotherapy and were randomized either to myeloablative chemoradiotherapy with autologous purged bone marrow rescue or to nonmyeloablative chemotherapy. Subsequently, they were randomized to 13-cis-retinoic acid or no further treatment. Immunocytologic analyses of bone marrow and blood were performed at diagnosis, week 4, week 12, bone marrow collection, and end induction and were correlated with tumor biology, clinical variables, treatment regimen, and event-free survival (EFS).

RESULTS

Immunocytology identified neuroblastoma cells in bone marrow of 81% at diagnosis, 55% at 4 weeks, 27% at 12 weeks, 19% at bone marrow collection, and 14% at end induction. Tumor cells were detected in blood of 58% at diagnosis and 5% at collection. There was an adverse effect on EFS of increasing tumor cell concentration in bone marrow at diagnosis (P =.04), at 12 weeks (P =.006), at bone marrow collection (P <.001), and at end induction (P =.07). Positive blood immunocytology at diagnosis was associated with decreased EFS (P: =.003). The prognostic impact of immunocytology was independent of morphologically detected bone marrow disease, MYCN status, and serum ferritin level in bivariate Cox analyses.

CONCLUSION

Immunocytologic quantification of neuroblastoma cells in bone marrow and blood at diagnosis and in bone marrow during induction chemotherapy provides prognostic information that can identify patients with very high-risk disease who should be considered for experimental therapy that might improve outcome.

p53 mutations and loss of p53 function confer multidrug resistance in neuroblastoma

BACKGROUND

Neuroblastomas often acquire sustained drug resistance during therapy. Sensitivities to carboplatin, etoposide, or melphalan were determined for 18 neuroblastoma cell lines; eight were sensitive and ten were resistant. As p53 mutations are rare in neuroblastomas studied at diagnosis, we determined if acquired p53 mutations and loss of function conferred multidrug resistance.

RESULTS

Loss of p53 function (p53-LOF), defined as a failure to induce p21 and/or MDM2 in response to melphalan, was seen in 1/8 drug-sensitive and 6/10 drug-resistant cell lines. In four cell lines p53-LOF was associated with mutations in the DNA binding region of p53, while three cell lines with LOF and four cell lines with functional p53 had no evidence of p53 muta-tions. Nonfunctional and mutated p53 was detected in one resistant cell line, while a sensitive cell line derived from the same patient prior to treatment had functional and wild type (wt) p53. We transfected HPV 16 E6 (which mediates degradation of p53, causing LOF) into two drug-sensitive neuroblastoma cell lines with functional p53. LC(90) values of HPV 16 E6 transfected cell lines were 3-7-fold (melphalan), 8-109-fold (carboplatin), and 2-158-fold (etoposide) greater than that of LXSN-transfected controls.

CONCLUSIONS

These data suggest that some neuroblastomas acquire p53 mutations during therapy, which is associated with a loss of p53 function, and can confer high-level multidrug resistance.

Prognostic significance of GAGE detection in bone marrows on survival of patients with metastatic neuroblastoma

BACKGROUND

Previously, we reported the utility of GAGE as a molecular marker for neuroblastoma (NB) and malignant melanoma in blood and bone marrow (BM). Among patients with stage III melanoma rendered disease-free by surgery, GAGE expression was a strong prognostic factor for patient survival.

PROCEDURE

All patients with advanced NB diagnosed at > 1 year of age initially treated with protocol N6 (n = 24) and N7 (n = 38) at Memorial Sloan-Kettering Cancer Center were included in this study. Their BM cells at 12, 18, and 24 months (median time after diagnosis) were evaluated for the presence of GAGE.

RESULTS

GAGE positivity at 12 months (25%), when patients were still on treatment, did not predict progression-free survival (PFS) and overall survival from the time of sampling. Positivity at 18 months (29%) was associated with poorer PFS and survival (but P > 0.05). By 24 months, the presence of GAGE (26%) was a very strong predictor of out-come (P < 0.001). When only remission marrows at 24 months were analyzed, PFS was 4.7-fold lower among GAGE-positive patients. Thirty-seven percent of N6 patients were positive for GAGE, in contrast to 17% of the patients in the more current regimen N7.

CONCLUSIONS

The detection of GAGE by RT-PCR in marrow may have utility in molecular staging of patients in clinical remission. It may allow earlier identification of patients at risk, such that appropriate intervention can be given before clinical relapse. GAGE may also serve as a surrogate endpoint for adjuvant treatment strategies, and to determine the duration of therapy.

Retinoic-acid-resistant neuroblastoma cell lines show altered MYC regulation and high sensitivity to fenretinide

BACKGROUND

High-dose, pulse-13-cis-retinoic acid (13-cis-RA) given after intensive cytotoxic therapy improves event-free survival for high-risk neuroblastoma (NB), but more than 50% of patients have tumor recurrence.

PROCEDURE

We conducted multistep selection for resistance to all-trans-retinoic acid (ATRA) in NB cell lines with (SMS-KCNR and LA-N-5) or without (SMS-LHN) MYCN genomic amplification.

RESULTS

After 12 exposures to 10 microM ATRA, the two MYCN-amplified cell lines (KCNR 12X RR and LA-N-5 12X RR) showed partial resistance to the cytostatic/differentiation effects of ATRA; complete resistance was seen in LHN 12X RR. ATRA-selected cells showed general RA resistance (cross-resistance to 13-cis-RA). Transient (KCNR 12 X RR, LA-N-5 12X RR) or sustained (LHN 12X RR) novel overexpression of c-myc was associated with RA resistance. RA-insensitive overexpression of MYCN by transduction in SMS-LHN also conferred RA resistance. Both parental and RA-resistant lines showed 2-4 logs of cell kill in response to N-(4-hydroxyphenyl)retinamide (4- HPR, fenretinide). Compared to parental lines, 4-HPR achieved 1-3 log greater cell kills in RA-resistant LHN 12X RR, LA-N-5 12X RR, KCNR 12X RR, and MYCN-transduced SMS-LHN or SK-N-RA. NB cell lines (n = 26) from 21 different patients showed that 16 of 26 (62%) were sensitive to 4-HPR (LC(90) < 10 microM), including lines established at relapse after myeloablative and/or 13-cis-RA therapy.

CONCLUSION

Thus, RA-resistant NB cell lines can be sensitive (and in some cases collaterally hypersensitive) to 4-HPR.

CD34 selection as a stem cell purging strategy for neuroblastoma: preclinical and clinical studies

BACKGROUND

The suitability of CD34 selection for purging peripheral blood progenitor cells (PBPC) collected from patients with neuroblastoma (NB) has been called into question, largely because of reports of detection of low levels of CD34 on the surface of some NB cell lines and tumors.

PROCEDURE

We used three approaches to address the issue of purging of NB from stem cell specimens and possible labeling of NB: 1) Flow cytometric detection of CD34 on NB cell lines. We assessed CD34 expression using a panel of anti-CD34 monoclonal antibodies (MoAbs) including 9C5, 12.8, and QBend10 and showed no increase in labeling over secondary-only control. 2) Spiking experiments with the Isolex 50 system. NB cell lines were used to contaminate aliquots of PBPC collections, after which the products were purified using the Isolex 50. Purging of NB was assessed by quantitative multiplex RT-PCR (TaqMan system) using a tumor-specific transcript, GAGE. We demonstrated >2 logs of tumor cell depletion from these specimens. 3) Analysis of clinical specimens. PBPC pre- and post-CD34 selection were analyzed from patients treated on the CHP-594 transplant trial.

RESULTS

In nine specimens selected using the Ceprate LC CD34 selection system where tumor was detectable by immunocytochemistry preselection, we observed >2.4 to >4.6 logs of NB purging after selection. We then analyzed 23 aliquots of PBPC infused into patients post-CD34 selection and compared them to the product preselection; 20/23 specimens showed depletion of NB, although some level of GAGE message was observed in most post-CD34 selection specimens.

CONCLUSION

These data show that purging of NB from PBPC specimens using CD34 selection is feasible, yielding infused products that are negative at the level of ICC but often positive at the level of RT-PCR.

Synergism of buthionine sulfoximine and melphalan against neuroblastoma cell lines derived after disease progression

BACKGROUND

Despite intensive-alkylator based regimens, >50% of patients with high-risk neuroblastoma (NB) die from recurrent disease that is probably due, in part, to acquired alkylator resistance.

PROCEDURE

Using buthionine sulfoximine (BSO)-mediated, glutathione (GSH) depletion to modulate melphalan (L-PAM) resistance, we examined six NB cell lines established after progressive disease following either standard chemotherapy, BSO/L-PAM therapy, or myeloablative therapy and autologous hematopoietic stem cell transplant (AHSCT).

RESULTS

Four of the six cell lines (three p53-nonfunctional and one p53-functional) showed high-level L-PAM resistance.

CONCLUSIONS

Fixed ratio analysis demonstrated BSO/L-PAM synergy (combination index >1) for all cell lines tested. In L-PAM-resistant cell lines, the minimal cytotoxicity observed for BSO combined with nonmyeloablative concentrations of L-PAM was markedly enhanced (>4 logs total cell kill) when BSO was combined with myeloablative concentrations of L-PAM. In alkylator-resistant NB, the optimal use of BSO may require dose escalation of L-PAM to levels requiring AHSCT.

Inhibition of tumor growth in a human neuroblastoma xenograft model with TNP-470

Background and Procedure High-risk neuroblastoma disease features are correlated with tumor vascularity, suggesting that angiogenesis inhibitors may be a useful addition to current therapeutic strategies. We therefore examined the efficacy of TNP-470 (TAP Pharmaceuticals, Deerfield, IL) in human neuroblastoma xenograft models.

RESULTS

Tumor growth rate was markedly inhibited in mice receiving TNP-470 administered alone with a treatment to control ratio (T/C) at day 21 = 0.4 (P <.001). TNP-470 also significantly inhibited tumorigenicity when administered shortly after xenograft inoculation (T/C at day 30 = 0.1, P <.001) and when administered following cyclophosphamide (T/C at day 35 = 0.1, P <.001).

CONCLUSIONS

These data show that TNP-470 is a potent inhibitor of human neuroblastoma growth both alone and when given with conventional chemotherapy, suggesting that it may be a useful adjunctive therapy for high-risk neuroblastoma patients.

Rapid-sequence tandem transplant for children with high-risk neuroblastoma

BACKGROUND

The majority of patients with high risk neuroblastoma (NB) still relapse.

PROCEDURE

We designed a Phase II trial for children with advanced NB utilizing a program of induction chemotherapy followed by tandem high-dose chemoradiotherapy with stem cell rescue (HDC/SCR) in rapid sequence. Fifty-five patients were evaluable, ages 1-14 years, and 97 cycles of HDC/SCR have been completed to date. Pheresis was possible for every patient, despite their young age, with an average of 7.2 x 10(6) CD34+ cells/kg available to support each HDC/SCR cycle.

RESULTS

Engraftment was rapid, with median time to neutrophil engraftment of 11 days. Five patients who completed the first HDC course did not complete the second and there were four toxic deaths. With a median follow-up of 24 months from diagnosis, 38 of 55 patients (3-year EFS 59%) remain event-free. A subset of the patients received stem cells purged by CD34 selection. The engraftment and EFS of these patients are similar to the overall group.

CONCLUSION

This work demonstrates that a tandem transplant regimen for high-risk NB is a feasible treatment strategy in children and may improve disease-free survival.

Phase I topotecan preparative regimen for high-risk neuroblastoma, high-grade glioma, and refractory/recurrent pediatric solid tumors

We evaluated the toxicity and maximum tolerated dose of topotecan in a novel myeloablative regimen as treatment for high-risk pediatric tumors. Patients received an assigned topotecan dosage in combination with fixed doses of carboplatin and thiotepa, followed by autologous hematopoietic stem cells infusion. Topotecan dose was escalated in cohorts of four patients until the maximum tolerated dose of topotecan was defined or until accrual of 30 patients. Pharmacokinetics of topotecan were examined, and event-free survival was estimated. We describe preliminary results following treatment of 25 pediatric patients with high-risk solid tumors.

Histone deacetylase inhibitors and retinoic acids inhibit growth of human neuroblastoma in vitro

BACKGROUND

Neuroblastoma is a common childhood cancer with a poor overall prognosis. Retinoic acids (RAs) have been studied as a potential therapy, showing promise in recurrent disease. The histone deacetylase inhibitor (HDACI) M-carboxycinnamic acid bishydroxamide (CBHA) is another potential therapy, which we recently described. Combinations of RAs and HDACIs currently under investigation display synergy in certain neoplasms. In this study, we evaluate the effect of combinations of RAs and HDACIs on human neuroblastoma cells.

PROCEDURE

Established cell lines were cultured in increasing concentrations of HDACIs, RAs, and combinations thereof. Following exposure, viable cell number was quantified by trypan blue dye exclusion on a hemacytometer. Cell cycle analysis was performed by propidium iodide staining and FACS.

RESULTS

All assayed HDACIs and RAs decreased viable cell number. Lower concentrations of each agent were effective when the two were combined. The primary reason for decreased cell number appears to be apoptosis following HDACI exposure and G1 arrest following RA exposure. Both effects are seen with cotreatment. Caspase inhibition abrogates the apoptotic response.

CONCLUSIONS

CBHA causes apoptosis of human neuroblastoma in vitro, an effect that can add to the effects of RA. HDACIs and RAs inhibit neuroblastoma in significantly lower concentrations when used together than when used individually. Combination therapy may improve the ultimate efficacy while reducing the side effects of these agents in clinical use.

Expression of the HMGI(Y) gene products in human neuroblastic tumours correlates with differentiation status

HMGI and HMGY are splicing variants of the HMGI(Y) gene and together with HMGI-C, belong to a family of DNA binding proteins involved in maintaining active chromatin conformation and in the regulation of gene transcription. The expression of the HMGI(Y) gene is maximal during embryonic development, declines in adult differentiated tissues and is reactivated in most transformed cells in vitro and in many human cancers in vivo. The HMGI(Y) genomic locus is frequently rearranged in mesenchymal tumours, suggesting a biological role for HMGI(Y) gene products in tumour biology. HMGIs are both target and modulators of retinoic acid activity. In fact, HMGI(Y) gene expression is differentially regulated by retinoic acid in retinoid-sensitive and -resistant neuroblastoma cells, while HMGI-C participates in conferring retinoic acid resistance in some neuroblastoma cells. In this paper we show that HMGI and HMGY isoforms are equally regulated by retinoic acid in neuroblastoma cell lines at both RNA and protein levels. More importantly our immunohistochemical analysis shows that, although HMGI(Y) is expressed in all neuroblastic tumours, consistently higher levels are observed in less differentiated neuroblastomas compared to more differentiated ganglioneuromas, indicating that HMGI(Y) expression should be evaluated as a potential diagnostic and prognostic marker in neuroblastic tumours.

Distinct properties of fenretinide and CD437 lead to synergistic responses with chemotherapeutic reagents

The RARbeta/gamma-selective retinoids fenretinide and CD437 induce caspase-dependent apoptosis but generate free radicals independently of caspases. Apoptosis, but not free radical generation, induced by these retinoids is inhibited by RARbeta/gamma-specific antagonists. Both fenretinide and CD437 induce apoptosis synergistically with cisplatin, carboplatin, or etoposide. However, antioxidants inhibit this synergy to the level obtained with chemotherapeutic drugs alone, and this implies that free radical generation is important in the synergistic response. Since apoptosis induced by fenretinide or CD437 is mediated by apoptotic pathways involving RARs and/or mitochondria and differs from mechanisms of chemotherapy-induced apoptosis this may explain the strong synergistic response seen between these synthetic retinoids and chemotherapeutic drugs. These results suggest that fenretinide or CD437 may be useful adjuncts to neuroblastoma therapy.

Improved survival for patients with advanced neuroblastoma after high-dose combined chemotherapy based in part on N-myc amplification

BACKGROUND/PURPOSE

In spite of many different kinds of chemotherapy for neuroblastoma, the prognosis for advanced neuroblastoma remains unsatisfactory. In particular, the outcome of advanced neuroblastoma with high copies of the N-myc gene tend to be poor. Therefore, the new high-dosage combined chemotherapy regimens for advanced neuroblastoma based in part on the N-myc amplification status has been utilized in the Kyushu area of Japan since 1991. This study aims to investigate whether these new regimens based in part on N-myc amplification have improved the survival rate of stage III and stage IV patients in comparison with the old regimens.

METHODS

Between 1983 and 1995, 77 patients over 1 year of age and with stage III or IV neuroblastoma were registered in the Kyushu Area. Between 1983 and 1990, 49 patients received 1 of 2 combined chemotherapy regimens consisting of cyclophosphamide, cisplatin plus VM-26, and Adriamycin plus DTIC. Since 1991, two new regimens (New A1 and A3) have been administered based on the N-myc amplification status in a total of 28 patients. The New A1 regimen, which consists of cyclophosphamide, cisplatin, Adriamycin, and VP-16 has been administered in cases of less than 10 copies of N-myc, whereas the A3 regimen, consisting of a higher dose of cyclophosphamide, cisplatin, Adriamycin, and VP-16, has been administered in cases of more than 10 copies of N-myc. The survival rate was then compared between the old regimens and the new regimens.

RESULTS

The 3-year survival rate (61.5%) for patients treated by the new regimens was significantly higher than that (32.7%) for patients treated by the old regimens (P <.01). Regarding the 24 cases of more than 10 copies of N-myc, the 3-year survival rate (35.9%) of the 13 patients treated by the A3 regimen was higher than that (0%) of the 11 patients treated by the old regimens (P <.05). However, in the 19 stage IV patients treated by the new regimens, the 3-year survival rate (11.1%) of the 9 cases of more than 10 copies was significantly lower than that (77.8%) of the 10 cases of less than 10 copies of N-myc (P <.01).

CONCLUSIONS

These results suggest that high-dose combined chemotherapy based in part on the N-myc amplification status significantly improved the prognosis of patients with advanced neuroblastoma. However, stage IV patients with N-myc amplification still require a more effective treatment modality.

Deletion of 11q23 is a frequent event in the evolution of MYCN single-copy high-risk neuroblastomas

BACKGROUND

Deletions of the long arm of chromosome 11 are frequently identified in human neuroblastomas.

PROCEDURE

We screened 394 primary neuroblastomas and 52 tumor-derived cell lines with a panel of 11q and 11p polymorphic markers to determine the frequency of chromosome 11 allelic deletion, and to differentiate partial deletions of chromosome 11q (unb[11q] LOH) from whole chromosome loss.

RESULTS

Allelic deletion occurred most frequently at cytogenetic band 11q23 and was detected in 161 primary neuroblastomas (41%) and 18 cell lines (35%). Eighty-seven tumors (22%) had unb[11q] LOH with a heterogeneous distribution of deletion breakpoints. Unb[11q] LOH was highly correlated with age > 1 year at diagnosis (P = 0.008), stage 4 disease (P = 0.001), unfavorable Shimada histopathology (P < 0.001), and assignment to a high-risk therapeutic protocol (P < 0.001), and was inversely correlated with MYCN amplification (P = 0.018). Patients whose tumors showed unb[11q] LOH were less likely to survive (P < 0.001), but there was only a trend towards an independent prognostic influence in multivariate analyses.

CONCLUSIONS

Thus, structural rearrangements resulting in unb[11q] LOH commonly occur during the malignant evolution of high-risk neuroblastomas with single-copy MYCN.

In vivo cytoreduction studies and cell sorting--enhanced tumor-cell detection in high-risk neuroblastoma patients: implications for leukapheresis strategies

PURPOSE

To improve autologous leukapheresis strategies in high-risk neuroblastoma (NB) patients with extensive bone marrow involvement at diagnosis.

PATIENTS AND METHODS

Anti-G(D2) immunocytochemistry (sensitivity, 1 in 10(5) to 10(6) leukocytes) was used to evaluate blood and bone marrow disease at diagnosis and during the recovery phase of the first six chemotherapy cycles in 57 patients with stage 4 NB and bone marrow disease at diagnosis. A total of 42 leukapheresis samples from the same patients were evaluated with immunocytology, and in 24 of these patients, an anti-G(D2) immunomagnetic enrichment step was used to enhance tumor-cell detection.

RESULTS

Tumor cytoreduction was much faster in blood compared with bone marrow (3.2 logs after the first cycle and 2.1 logs after the first two cycles, respectively). Bone marrow disease was often detectable throughout induction, with a trend to plateau after the fourth cycle. By direct anti-G(D2) immunocytology, a positive leukapheresis sample was obtained in 7% of patients after either the fifth or sixth cycle; when NB cell immunomagnetic enrichment was applied, 25% of patients had a positive leukapheresis sample (sensitivity, 1 in 10(7) to 10(8) leukocytes).

CONCLUSION

Standard chemotherapy seems to deliver most of its in vivo purging effect within the first four cycles. In patients with overt marrow disease at diagnosis, postponing hematopoietic stem-cell collection beyond this point may not be justified. Tumor-cell clearance in blood seems to be quite rapid, and earlier collections via peripheral-blood leukapheresis might be feasible. Immunomagnetically enhanced NB cell detection can be highly sensitive and can indicate whether ex vivo purging should be considered.

MYCN expression is not prognostic of adverse outcome in advanced-stage neuroblastoma with nonamplified MYCN

PURPOSE

The clinical significance of MYCN expression in children with neuroblastoma (NB) remains controversial. To determine the prognostic significance of MYCN expression in the absence of MYCN amplification, we analyzed MYCN mRNA and protein expression in tumors from 69 patients.

PATIENTS AND METHODS

Sixty-nine NB tumor samples with nonamplified MYCN from patients with stage C or D disease were obtained from the Pediatric Oncology Group Neuroblastoma Tumor Bank. MYCN mRNA was analyzed using a real-time reverse transcriptase polymerase chain reaction assay, and MYCN protein was examined by Western blot analyses.

RESULTS

The estimated 5-year event-free survival (EFS) and survival (S) rates plus SE for the cohort were 57% +/- 17% and 60% +/- 16%, respectively. Infants younger than 1 year had significantly higher rates of EFS and S than children >/= 1 year of age (P =.003 and P <.001, respectively); patients with stage C disease had better outcome than those with stage D NB (P <.001); and patients with hyperdiploid tumors had better outcome than those with diploid NB (P <.001). Surprisingly, outcome was slightly better for patients with high versus low levels of MYCN mRNA expression (4-year S, 70% +/- 13% v 50% +/- 16%; P =.290), and for patients with tumors that expressed MYCN protein (4-year S, 73% +/- 19% v 53% +/- 15%, respectively; P =.171).

CONCLUSION

High levels of MYCN expression are not prognostic of adverse outcome in patients with advanced-stage NB with nonamplified MYCN. A trend associating high levels of MYCN expression with improved outcome was observed.

A randomized trial of 13-Cis retinoic acid in children with advanced neuroblastoma after high-dose therapy

One hundred and seventy-five children with Stage 3 or 4 neuroblastoma who had obtained a good response to conventional therapy were randomly allocated to 13-Cis retinoic acid at a dose of 0.75 mg/kg/day or placebo for up to 4 years. Toxicity was mild but no advantage in event-free survival was shown for the children receiving retinoic acid.

Differentiating agents in pediatric malignancies: retinoids in neuroblastoma

Retinoids are derivatives of vitamin A that include all- trans-retinoic acid (ATRA), 13-cis-retinoic acid, (13-cis-RA), and fenretinide (4-HPR). High levels of either ATRA or 13-cis-RA can cause arrest of cell growth and morphologic differentiation of human neuroblastoma cell lines. Phase I trials have shown that higher and more sustained drug levels were obtained with 13-cis-RA relative to ATRA. A phase III randomized trial showed that high-dose pulse therapy with 13-cis-RA given after completion of intensive chemoradiotherapy (with or without autologous bone marrow transplantation) significantly improves event-free survival in high-risk neuroblastoma. Because 4-HPR achieves multi-log cell kills in neuroblastoma cell lines that are resistant to ATRA and 13-cis-RA, a pediatric phase I trial is in progress to determine the maximum tolerated dose of 4-HPR, with a view toward giving 4-HPR after completion of myeloablative therapy and 13-cis-RA.

Monoclonal antibody-based therapy for neuroblastoma

Dose-intensive combination chemotherapy can improve the clinical response of many pediatric solid tumors. However, cure remains elusive. Stage 4 neuroblastoma stands out as an exception. Part of this success is a result of antibody-based strategies, which include immunomagnetic purging of autologous marrow prior to autologous marrow transplantation and immunotherapy directed at minimal residual disease. It is striking that treatment with monoclonal antibodies, even when targeted at a single antigen, namely, ganglioside G(D2), can affect long-term progression-free survival among these patients. The potential role of the idiotype network in tumor control can be exploited clinically. The genetic engineering of these antibodies into novel forms holds great promise for more specific and effective targeting possibilities, including the delivery of cytokines and cells. Preclinical results are also promising. It is expected that the availability of novel antibodies directed at a broader spectrum of pediatric solid tumors will facilitate the successful application of this approach to more patients. Experience with metastatic neuroblastoma has provided proof of this principle. It is likely that other tumors will fall.

Pharmacokinetics of chronically administered all-trans-retinoyl-beta-glucuronide in mice

After the subcutaneous injection of retinoyl beta-glucuronide (RAG), both RAG and retinoic acid (RA), formed by the hydrolysis of RAG in vivo, achieved peak plasma concentrations within 1-2 h. Thereafter, RA was rapidly cleared from the plasma whereas RAG was eliminated much more slowly. No significant changes were noted in the peak (2 h) plasma levels of RAG for treatment periods up to 56 days (one injection of RAG/day), in the clearance rate of RAG from plasma, or in plasma retinol concentrations. Similarly, no consistent decrease in plasma levels of the RA hydrolysis product was observed. Mice undergoing these long-term chronic treatments with RAG did not show any clinical manifestations of retinoid toxicity. Taken together, our findings that chronic dosing with RAG produces sustained levels of both the parent compound and the RA hydrolysis product, combined with the apparent low toxicity of RAG, suggest that RAG could be a safe and useful alternative to some retinoids which are presently being utilized in the clinic.

Arsenic trioxide inhibits neuroblastoma growth in vivo and promotes apoptotic cell death in vitro

Recent clinical studies have shown that inorganic arsenic trioxide (As(2)O(3)) at low concentrations induces complete remission with minimal toxicity in patients with refractory acute promyelocytic leukemia (APL). Preclinical studies suggest that As(2)O(3) induces apoptosis and possibly differentiation in APL cells. Like APL cells, neuroblastoma (NB) cells are thought to be arrested at an early stage of differentiation, and cells of highly malignant tumors fail to undergo spontaneous maturation. Both APL and NB cells can respond with differentiation to retinoic acid (RA) treatment in vitro and probably also in vivo. For that reason we investigated the effect of As(2)O(3) alone and in combination with RA on NB cell lines. In vitro, the number of viable NB cells was reduced at As(2)O(3) concentrations around 1 microM after 72 h exposure. The IC50 in six different cell lines treated for 3 days was in the 1.5 to 5 microM concentration interval, the most sensitive being SK-N-BE(2) cells derived from a chemotherapy resistant tumor. The combined treatment with RA (1 and 3 microM) showed no consistent additional effect with regard to induced cell death. The effect of As(2)O(3) on NB cell number involved As(2)O(3)-induced apoptotic pathways (decreased expression of Bcl-2 and stimulation of caspase-3 activity) with no clear evidence of induced differentiation. The in vivo effect of As(2)O(3) on NB growth was also investigated in nude mice bearing tumors of xenografted NB cells. Although tumor growth was reduced by As(2)O(3) treatment, complete remission was not achieved at the concentrations tested. We suggest that As(2)O(3), in combination with existing treatment modalities, might be a treatment approach for high risk NB patients.

Effector mechanisms of fenretinide-induced apoptosis in neuroblastoma

Fenretinide is an effective inducer of apoptosis in many malignancies but its precise mechanism(s) of action in the induction of apoptosis in neuroblastoma is unclear. To characterize fenretinide-induced apoptosis, neuroblastoma cell lines were treated with fenretinide and flow cytometry was used to measure apoptosis, free radical generation, and mitochondrial permeability changes. Fenretinide induced high levels of caspase-dependent apoptosis accompanied by an increase in free radicals and the release of cytochrome c in the absence of mitochondrial permeability transition. Apoptosis was blocked by two retinoic acid receptor (RAR)-beta/gamma-specific antagonists, but not by an RARalpha-specific antagonist. Free radical induction in response to fenretinide was not blocked by the caspase inhibitor ZVAD or by RAR antagonists and was only marginally reduced in cells selected for resistance to fenretinide. Therefore, free radical generation may be only one of a number of intracellular mechanisms of apoptotic signaling in response to fenretinide. These results suggest that the effector pathway of fenretinide-induced apoptosis of neuroblastoma is caspase dependent, involving mitochondrial release of cytochrome c independently of permeability changes, and mediated by specific RARs. As the mechanism of action of fenretinide may be different from other retinoids, this compound may be a valuable adjunct to neuroblastoma therapy with retinoic acid and conventional chemotherapeutic drugs.

Mechanism and relevance of ploidy in neuroblastoma

Neuroblastoma has a broad spectrum of clinical behavior, ranging from spontaneous regression to dissemination and fatality. The heterogeneity that has long puzzled many investigators has been shown by more recent studies to be closely correlated with various clinical and genetic factors. Tumor cell ploidy is one of the factors; diploid and near-triploid neuroblastomas show poor and excellent clinical outcomes, respectively. We offer a hypothesis that explains how the ploidy state of the tumor plays a fundamental role in this heterogeneity, and why various prognostic factors are correlated with each other. This hypothesis may be applicable to tumors other than neuroblastoma.

Retinoic acid selectively inhibits the vascular permeabilizing effect of VPF/VEGF, an early step in the angiogenic cascade

All-trans-retinoic acid (RA) and other retinoids modulate cell growth and differentiation, generally favoring terminal cell differentiation and inhibiting carcinogenesis. Retinoids are also reported to inhibit angiogenesis and endothelial cell migration, actions that are also anti-carcinogenic. Vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) is a multifunctional cytokine secreted by many tumors. It renders microvessels hyperpermeable to plasma and stimulates endothelial cell migration and division. To investigate further the mechanisms by which RA inhibits angiogenesis, we evaluated the effects of RA on VPF/VEGF-induced angiogenesis and microvascular permeability. RA selectively inhibited the angiogenic response induced by VPF/VEGF, but not that induced by fibroblast growth factor-2 (FGF-2), in the CAM assay. RA and two of its isomers also inhibited the vascular permeabilizing effect of VPF/VEGF but not that induced by histamine. The vascular permeabilization induced by VPF/VEGF and blocked by RA takes place within 1-15 min, too short a time frame for RA to act by modulating transcription through classic retinoid receptors. RA also inhibited VPF/VEGF-induced phosphorylation of PLC-gamma and synthesis of cGMP but actually increased VPF/VEGF binding to cultured endothelial cells. Taken together, these findings indicate that RA selectively blocks VPF/VEGF-induced microvascular permeability and angiogenesis and also identify VPF/VEGF as a major target of RA action. The selectivity of RA's action suggests that other, RA-independent pathways must exist for the angiogenesis induced by FGF-2 and the vascular permeabilizing effect of histamine.

[What is new in pediatric oncology?]

The significant progress made in pediatric oncology during recent years has been due to a major breakthrough in the field of molecular biology and the introduction of new therapeutic strategies that take into account both the quality and the duration of life. Molecular biology has already been instrumental in more fully categorizing the 'small round-cell tumor' group, and in reclassifying the 'Ewing family' tumors. It also provides a valuable tool for the prognostic evaluation of neuroblastomas through the analysis of the N-myc oncogene. In addition, it has permitted the identification of the Li-Fraumeni syndrome of predisposition to cancer in the child, thereby raising the problematical ethical issue of communicating relevant information to subjects at risk. Two examples illustrate innovative strategic concepts: 1) Burkitt's lymphoma, or an example of the successful de-intensification of treatment; and 2) brain tumors in young children, regarding which the desire to improve the quality of life has led to innovative attempts to replace radiotherapy by chemotherapy. Considerable progress has been made in the field of neuropsychology, thereby permitting an improved assessment of disorders and a better management of rehabilitation programs. New anti-cancer agents and also chemo- and radiotherapy that spare healthy tissue are also being developed. Gene therapy and molecular biology will play a major role in future therapeutic strategies; and are now at the preclinical trial stage. This significant overall progress leads to a reconsideration of the organizational approach toward treatment of the pediatric patient population suffering from cancer, and a critical assessment of disease management, which should take into account not only the technical aspects of the disease but also familial and social considerations.

Tandem high-dose therapy in rapid sequence for children with high-risk neuroblastoma

PURPOSE

Advances in chemotherapy and supportive care have slowly improved survival rates for patients with high-risk neuroblastoma. The focus of many of these chemotherapeutic advances has been dose intensification. In this phase II trial involving children with advanced neuroblastoma, we used a program of induction chemotherapy followed by tandem high-dose, myeloablative treatments (high-dose therapy) with stem-cell rescue (HDT/SCR) in rapid sequence.

PATIENTS AND METHODS

Patients underwent induction chemotherapy during which peripheral-blood stem and progenitor cells were collected and local control measures undertaken. Patients then received tandem courses of HDT/SCR, 4 to 6 weeks apart. Thirty-nine patients (age 1 to 12 years) were assessable, and 70 cycles of HDT/SCR were completed.

RESULTS

Pheresis was possible in the case of all patients, despite their young ages, with an average of 7.2 x 10(6) CD34(+) cells/kg available to support each cycle. Engraftment was rapid; median time to neutrophil engraftment was 11 days. Four patients who completed the first HDT course did not complete the second, and there were three deaths due to toxicity. With a median follow-up of 22 months (from diagnosis), 26 of 39 patients remained event-free. The 3-year event-free survival rate for these patients was 58%.

CONCLUSION

A tandem HDT/SCR regimen for high-risk neuroblastoma is a feasible treatment strategy for children and may improve disease-free survival.

Intraoperative radiation therapy for high-risk pediatric neuroblastoma

PURPOSE

To evaluate the efficacy of intraoperative radiation therapy (IORT) in the treatment of high-risk pediatric neuroblastoma.

METHODS AND MATERIALS

Between 1986 and 1998, 23 children received IORT for pediatric neuroblastoma. Electron beam energies ranged from 4 MeV to 16 MeV and median dose was 10 Gy (7-16 Gy).

RESULTS

Twenty-one of 23 patients were classified as high-risk. A gross total resection (GTR) was achieved in 18 patients, of whom 6 experienced disease recurrence, 2 of which included a locoregional relapse as a component of failure. Fourteen of 18 patients receiving IORT after a GTR are disease-free survivors. A second subset of 5 patients had a subtotal resection (STR), with gross residual disease remaining after surgery. All 5 patients recurred locally, and all died of their disease. IORT was extremely well-tolerated in our cohort. Surgical resection and IORT resulted in the narrowing of the abdominal aorta and an atrophic kidney in 1 patient.

CONCLUSIONS

For high-risk neuroblastoma patients, IORT as the only radiotherapy to the primary, produced excellent local control after a GTR. However, IORT as the sole radiotherapy to the primary was inadequate for patients with extensive adenopathy or an STR. In this setting, we are exploring the use of IORT as a boost in conjunction with external beam radiation therapy.

Neuroblastoma: current drug therapy recommendations as part of the total treatment approach

Neuroblastoma represents one of the most challenging malignancies for treatment decisions because of its unusual biological behaviour. The features include spontaneous regression (regressive type), maturation to ganglioneuroma (maturative type) and largely treatment-resistant progression (progressive type). Current knowledge allows only partial prediction of type. For practical reasons, patients may be categorised as an 'observation', a 'standard risk' or a 'high risk' treatment arm. During the last 2 decades, 5-year survival rates for children with neuroblastoma have increased from 48 to 67%. The main achievements were the reduction of chemotherapy in patients with localised disease and the increased efficacy of chemotherapy in metastatic neuroblastoma stage 4 (5-year survival increased from 8 to 33%). Different goals for chemotherapy (e.g. stopping rapid progression, improvement of symptoms, induction and maintenance of remission) require different dosages and durations of treatment (range 1 week to 9 months). The main risks of chemotherapy are toxic death (rate up to 15%) predominantly during the periods of bone marrow depression and the development of secondary leukaemias (up to 7% cumulative risk after 4 years). In conclusion, the use of cytotoxic drugs can be completely omitted in a substantial proportion of low risk patients with neuroblastoma. On the other hand, for high risk patients with the disease, intensive polychemotherapy represents the basis and the backbone of treatment among other modalities.

Clinical prognostic factors in 1277 patients with neuroblastoma: results of The European Neuroblastoma Study Group 'Survey' 1982-1992

In 1982 the European Neuroblastoma Study Group (ENSG) established a prospective registry for patients with newly diagnosed neuroblastoma ('The ENSG Survey'). Clinical information was collected primarily to: (a) establish an ENSG database; and (b) investigate prognostic factors in neuroblastoma. This paper summarises the results of the survey. By 1992, 1277 patients with a median age of 26 months (range: 0-289 months), gender ratio of 1.19 M:F had been registered from 30 centres. The median follow-up of survivors is 9.7 years (range: 1-14 years). Overall 5-year survival (S) is 45% (95% CI 42-48%), and event-free survival (EFS) is 43% (95% CI 40-45%). For both survival and EFS the key established prognostic factors, stage and age, are highly significant (P<0.001). In particular, patients under 1 year of age at diagnosis, whatever the disease stage, had a more favourable prognosis than older patients; stage 2 (EFS 93% (95% (CI 85-97) versus 76% (95% CI 67-86), P=0.02), stage 3 (EFS 91% (95% CI 82-96) versus 52% (95% CI 44-60), P<0.001) and stage 4 (EFS 59% (95% CI 48-69) versus 16% (95% CI 13-19), P<0.001). Multivariate analysis established that the anatomical location of the primary tumour (i.e. abdominal versus other sites) and primary tumour volume also conferred a statistically significant difference. In stage 4 disease the 20% of patients without demonstrable bone marrow involvement had a more favourable prognosis than those with infiltrated marrow (EFS 36% (95% CI 13-19) versus 16% (95% CI 29-45), P<0.001). Urine catecholamine metabolite levels (raised versus normal), histology (ganglioneuroblastoma versus neuroblastoma) and gender had no significant effect on outcome after stage and age were accounted for. 5-year survival following first relapse is only 5.6% (95% CI 2.8-8.4). This ENSG Survey provides secure data for future comparisons with new prognostic factors and treatment programmes.