Radiation therapy for consolidation of metastatic or recurrent sarcomas in children treated with intensive chemotherapy and stem cell rescue. A feasibility study

Risk stratification of pulmonary toxicities in the combination of whole lung irradiation and high-dose chemotherapy for Ewing sarcoma patients with lung metastases: a review

BACKGROUND

Whole lung irradiation (WLI) represents an important part of multimodal therapy in Ewing sarcoma (EwS) patients diagnosed with pulmonary metastases. This review discusses pulmonary toxicity in EwS patients with pulmonary metastases treated with WLI, who received different modes of high-dose chemotheray (HD-Cth).

METHODS

Literature was compiled using the Cochrane Library, PubMed database, and the National Institute of Health (NIH) clinical trials register. Relevant patient information, including nature of HD-Cth, acute and late lung toxicities, and pulmonary function disorders, was selected from the above databases.

RESULTS

Nine reports with a total of 227 patients, including 57 patients from a single randomized trial were included in this review. No acute or chronic symptomatic pulmonary toxicities were observed in patients that received WLI after HD busulfan-melphalan (HD-Bu/Mel), but 8% of these patients were diagnosed with asymptomatic restrictive lung disease. Grade 1 or 2 acute or chronic lung adverse effects were observed in up to 30% of patients that received WLI after HD treosulfan/Mel (HD-Treo/Mel) or HD etoposide (E)/Mel. Interstitial pneumonitis was present in 9% of patients treated concurrently with E/Mel and total body irradiation (TBI) with 8 Gy. Radiation doses as well as time between HD-Cth and WLI were both identified as significant risk factors for pulmonary function disorders.

CONCLUSION

The risk of adverse lung effects after WLI depends on several factors, including cumulative radiation dose and dose per fraction, HD-Cth regimen, and time interval between HD-Cth and WLI. A cumulative radiation dose of up to 15 Gy and a time interval of at least 60 days can potentially lead to a reduced risk of pulmonary toxicities. No evident adverse lung effects were registered in patients that received simultaneous therapy with HD-Cth and TBI. However, pulmonary function testing and lung toxicity reports were lacking for most of these patients.

Autologous hematopoietic stem cell transplantation following high dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity. The rationale for this update is to determine whether any randomized controlled trials (RCTs) have been conducted and to clarify whether HDCT followed by autologous HSCT has a survival advantage.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) in children and adults.

SEARCH METHODS

For this update we modified the search strategy to improve the precision and reduce the number of irrelevant hits. All studies included in the original review were considered for re-evaluation in the update. We searched the electronic databases CENTRAL (2012, Issue 11) in The Cochrane Library , MEDLINE and EMBASE (05 December 2012) from their inception using the newly developed search strategy. Online trials registers and reference lists of systematic reviews were searched.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title or abstract. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Single-arm studies were included in addition to studies with a control arm because the number of comparative studies was expected to be very low.

DATA COLLECTION AND ANALYSIS

Two review authors independently extracted study data. Some studies identified in the original review were re-examined and found not to meet the inclusion criteria and were excluded in this update. For studies with no comparator group, we synthesized the results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM).

MAIN RESULTS

The selection process was carried out from the start of the search dates for the update. We included 57 studies, from 260 full text articles screened, reporting on 275 participants that were allocated to HDCT followed by autologous HSCT. All studies were not comparable due to various subtypes. We identified a single comparative study, an RCT comparing HDCT followed by autologous HSCT versus standard chemotherapy (SDCT). The overall survival (OS) at three years was 32.7% versus 49.4% with a hazard ratio (HR) of 1.26 (95% confidence interval (CI) 0.70 to 2.29, P value 0.44) and thus not significantly different between the treatment groups. In a subgroup of patients that had a complete response before treatment, OS was higher in both treatment groups and OS at three years was 42.8% versus 83.9% with a HR of 2.92 (95% CI 1.1 to 7.6, P value 0.028) and thus was statistically significantly better in the SDCT group. We did not identify any other comparative studies. We included six single-arm studies reporting aggregate data of cases; three reported the OS at two years as 20%, 48%, and 51.4%. One other study reported the OS at three years as 40% and one further study reported a median OS of 13 months (range 3 to 19 months). In two of the single-arm studies with aggregate data, subgroup analysis showed a better OS in patients with versus without a complete response before treatment. In a survival analysis of pooled individual data of 80 participants, OS at two years was estimated as 50.6% (95% CI 38.7 to 62.5) and at three years as 36.7% (95% CI 24.4 to 49.0). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. The one included RCT had a low risk of bias and the remaining 56 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

A single RCT with a low risk of bias shows that OS after HDCT followed by autologous HSCT is not statistically significantly different from standard-dose chemotherapy. Therefore, HDCT followed by autologous HSCT for patients with NRSTS may not improve the survival of patients and should only be used within controlled trials if ever considered.

High-dose chemotherapy and stem cell rescue for high-risk Ewing's family of tumors

The prognosis for high-risk Ewing's tumors has been improved by multimodal radiation and chemotherapy. Ewing's family of tumors requires risk-adapted treatment. Risk stratification is dependent on stage, tumor localization and volume, and the pattern of disease spread at the time of diagnosis and the time of relapse. The concepts for high-dose therapy followed by hematopoietic cell transplantation in Ewing's family of tumors are based on dose-response and dose-intensity relationships. This article will discuss the use of high-dose therapy followed by hematopoietic cell transplantation, focusing on recent progress with respect to agent combinations, dose and outcomes of therapy.

Presentation, prognostic factors and patterns of failure in adult rhabdomyosarcoma

PURPOSE

The purpose of our study is to retrospectively review our institutional experience with adult rhabdomyosarcoma (RMS) to determine presentation, prognostic factors and patterns of failure in this disease.

MATERIALS AND METHODS

All patients >/= 16 years with a diagnosis of rhabdomyosarcoma were retrospectively reviewed. Tumors were classified according to the Intergroup Rhabdomyosarcoma Study (IRS) staging and grouping system. Median follow-up for surviving patients was 12.5 years.

RESULTS

A total of 39 patients (23 male, 16 female) were seen at our institution from 1961 to 1999. Median age was 45 years, and age distribution showed a bimodal peak at the late teens to twenties and later in the sixties. Tumor in the extremity was most common as seen in 15 (39%); this was followed by head and neck in 11 (28%), genitourinary in eight (20%), trunk/retroperitoneum in four (10%) and other in one (3%). Tumor stage was T1 in 21 (52%) while 26 (67%) were > 5 cm in size. Pleomorphic histology was most common (36%) and increased in incidence according to age category: 0% for ages 16-19, 27% for ages 20-49 and 60% for ages >/= 50 years old (P < 0.01). The median survival for the entire population was 2.25 years with a 5-year overall survival rate of 35%. Multivariate analysis identified early IRS stage (P < 0.001), non-embryonal histology (P < 0.009), favorable site (P = 0.024), female gender (P = 0.034), early T-stage (P = 0.034) and absence of nodal metastases (P = 0.037) as predictors of a better survival. The 5-year progression-free survival rate was 21%. Female gender (P = 0.002), non-embryonal histology (P = 0.009), early IRS stage (P = 0.02) and early T stage (P = 0.033) were found on multivariate analysis to predict for improved progression-free survival. The 5-year local control rate was 51%, and multivariate analysis found that only early T-stage was predictive of better local control (P = 0.045). Five of six Group II patients and five of eight Group III patients who received radiotherapy (RT) were locally controlled. Only one of five Group III patients was locally controlled without RT.

CONCLUSIONS

The overall prognosis of adult RMS is worse than reported in children, but age criteria within the adult population did not further classify outcome. RT is an effective local modality providing local control in almost all Group II and majority of Group III patients.

Camptothecin-based regimens for treatment of ewing sarcoma: past studies and future directions

New therapies are needed to improve survival for patients with Ewing sarcoma. Over the past decade, camptothecin agents such as topotecan and irinotecan have demonstrated activity against Ewing sarcoma, especially in combination with alkylating agents. Previous studies have shown camptothecin-based combinations to be tolerable outpatient strategies that are attractive for salvage therapy. This paper highlights important issues related to drug dosing, schedule of administration, pharmacokinetics, toxicity, and activity of commonly used camptothecin-based regimens. Also discussed are strategies for incorporating these regimens into therapy for newly diagnosed patients, including several potential possibilities for combination with targeted agents.

Autologous hematopoietic stem cell transplantation following high-dose chemotherapy for non-rhabdomyosarcoma soft tissue sarcomas

BACKGROUND

Soft tissue sarcomas (STS) are a highly heterogeneous group of rare malignant solid tumors. Non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) comprise all STS except rhabdomyosarcoma. In patients with advanced local or metastatic disease, autologous hematopoietic stem cell transplantation (HSCT) applied after high-dose chemotherapy (HDCT) is a planned rescue therapy for HDCT-related severe hematologic toxicity.

OBJECTIVES

To assess the effectiveness and safety of HDCT followed by autologous HSCT for all stages of soft tissue sarcomas in children and adults.

SEARCH STRATEGY

We searched the electronic databases CENTRAL (The Cochrane Library 2010, Issue 2), MEDLINE and EMBASE (February 2010). Online trial registers, congress abstracts and reference lists of reviews were searched and expert panels and authors were contacted.

SELECTION CRITERIA

Terms representing STS and autologous HSCT were required in the title, abstract or keywords. In studies with aggregated data, participants with NRSTS and autologous HSCT had to constitute at least 80% of the data. Comparative non-randomized studies were included because randomized controlled trials (RCTs) were not expected. Case series and case reports were considered for an additional descriptive analysis.

DATA COLLECTION AND ANALYSIS

Study data were recorded by two review authors independently. For studies with no comparator group, we synthesised results for studies reporting aggregate data and conducted a pooled analysis of individual participant data using the Kaplan-Meyer method. The primary outcomes were overall survival (OS) and treatment-related mortality (TRM).

MAIN RESULTS

We included 54 studies, from 467 full texts articles screened (11.5%), reporting on 177 participants that received HSCT and 69 participants that received standard care. Only one study reported comparative data. In the one comparative study, OS at two years after HSCT was estimated as statistically significantly higher (62.3%) compared with participants that received standard care (23.2%). In a single-arm study, the OS two years after HSCT was reported as 20%. In a pooled analysis of the individual data of 54 participants, OS at two years was estimated as 49% (95% CI 34% to 64%). Data on TRM, secondary neoplasia and severe toxicity grade 3 to 4 after transplantation were sparse. All 54 studies had a high risk of bias.

AUTHORS' CONCLUSIONS

Due to a lack of comparative studies, it is unclear whether participants with NRSTS have improved survival from autologous HSCT following HDCT. Owing to this current gap in knowledge, at present HDCT and autologous HSCT for NRSTS should only be used within controlled trials.

High-dose chemotherapy for children and young adults with stage IV rhabdomyosarcoma

BACKGROUND

Rhabdomyosarcoma is the most common soft tissue sarcoma of childhood. Prognosis for patients with metastatic disease has not improved significantly in the past decades. High-dose chemotherapy (HDC) seems to be an attractive option to treat minimal residual disease in metastatic rhabdomyosarcoma patients.

OBJECTIVES

The objective of the review was to assess the effectiveness of HDC with stem cell rescue (SRC) versus standard-dose chemotherapy in improving event-free survival (EFS) and overall survival (OS) of children and young adults with metastatic rhabdomyosarcoma.

SEARCH STRATEGY

We searched the databases of MEDLINE (1966 to December 2009), EMBASE (1980 to December 2009) and CENTRAL (The Cochrane Library Issue 1, 2009). In addition, we handsearched the reference lists of selected papers and conference proceedings of the SIOP, ASPHO and ASCO meetings (all 2000 to 2009).

SELECTION CRITERIA

Randomised controlled trials (RCT), prospective or historical controlled clinical trials (CCT), in which HDC with SCR was compared to conventional chemotherapy and prospective case series (non-controlled clinical trials) including at least 20 naive metastatic rhabdomyosarcoma patients

DATA COLLECTION AND ANALYSIS

Two review authors independently performed the study selection, quality assessment and data extraction.

MAIN RESULTS

No RCTs could be identified. We identified one prospective CCT, one retrospective CCT and one non-controlled clinical trial. Another CCT has been published as an abstract. All studies have severe methodological limitations, in particular selection bias could not be excluded. One CCT reported a significantly worse OS compared to oral maintenance therapy, however in a subgroup of high-risk patients no difference could be found. The retrospective CCT reported a similar survival for HDC compared to conventional chemotherapy. The non-controlled clinical trial and the CCT reported as a conference proceeding reported survival outcomes comparable to previous studies. Data on toxicity showed more grade 3-4 toxicity in the HDC group. However, there was no difference in the number of toxic deaths.

AUTHORS' CONCLUSIONS

Overall, the results of this review do not justify the use of HDC with SCR as a standard therapy for children with metastatic rhabdomyosarcoma. However, all reported studies were possibly subject to significant bias, especially selection bias. This might have underestimated the measured effect of HDC. As a result, a clinically important excess of adverse risk patients in the HDC arms may explain the non-beneficial effect of HDC. Only a large prospective RCT will be able to answer the question of whether HDC with SCR adds to survival or not definitively.

Positron emission tomography for staging of pediatric sarcoma patients: results of a prospective multicenter trial

PURPOSE

The objective of this study was to evaluate the impact of positron emission tomography (PET) using fluorine-18-fluorodeoxyglucose (FDG) for initial staging and therapy planning in pediatric sarcoma patients.

PATIENTS AND METHODS

In this prospective multicenter study, 46 pediatric patients (females, n = 22; males, n = 24; age range, 1 to 18 years) with histologically proven sarcoma (Ewing sarcoma family tumors, n = 23; osteosarcoma, n = 11; rhabdomyosarcoma, n = 12) were examined with conventional imaging modalities (CIMs), including ultrasound, computed tomography (CT), magnetic resonance imaging, and bone scintigraphy according to the standardized algorithms of the international therapy optimization trials, and whole-body FDG-PET. A lesion- and patient-based analysis of PET alone and CIMs alone and a side-by-side (SBS) analysis of FDG-PET and CIMs were performed. The standard of reference consisted of all imaging material, follow-up data (mean follow-up time, 24 +/- 12 months), and histopathology and was determined by an interdisciplinary tumor board.

RESULTS

FDG-PET and CIMs were equally effective in the detection of primary tumors (accuracy, 100%). PET was superior to CIMs concerning the correct detection of lymph node involvement (sensitivity, 95% v 25%, respectively) and bone manifestations (sensitivity, 90% v 57%, respectively), whereas CT was more reliable than FDG-PET in depicting lung metastases (sensitivity, 100% v 25%, respectively). The patient-based analysis revealed the best results for SBS, with 91% correct therapy decisions. This was significantly superior to CIMs (59%; P < .001).

CONCLUSION

In staging pediatric sarcoma, subsidiary FDG-PET scanning depicts important additional information and has a relevant impact on therapy planning when analyzed side-by-side with CIMs.

Long-term follow up of high-dose chemotherapy with autologous stem cell rescue in adults with Ewing tumor

Ewing tumors remain of poor prognosis, with 5-year overall survival of 55% to 65% in localized patients and not exceeding 25% in primarily metastatic disease. Several reports, mainly in children, have reported that some patients with poor-risk Ewing tumors may benefit from high-dose chemotherapy (HDCT) with autologous stem cell rescue. This retrospective study analyzed 46 patients treated in our institution between 1987 and 2000 for localized or primary metastatic Ewing tumors by HDCT followed by stem cell rescue. Median follow up was 7.1 years. Median age was 21 years (range, 15-46 years). Twenty-two percent of patients had metastases at diagnosis. The tumor site was axial in 56% of patients. Median tumor size was 9.5 cm. The treatment regimen consisted of induction chemotherapy, local treatment, maintenance chemotherapy, and consolidation HDCT based on alkylating agents. No toxic death was observed in the intensive therapy phase. Five-year overall survival and progression-free survival were 63 +/- 7.7% and 47 +/- 7.6%, respectively. Pejorative prognostic factors in this population were metastases at diagnosis (5-year overall survival 34% vs.71%, P = 0.017) and poor pathologic response (5-year overall survival 44% vs.77%, P = 0.03). This retrospective study shows a high long-term survival rate with high-dose chemotherapy in adults.

Ewing's sarcoma and primitive neuroectodermal family of tumors

Ewing's sarcoma (ES) initially was believed to be of perivascular endothelial origin. The Ewing's sarcoma family of tumors (EFT) includes ES of bone (ESB), extraosseous ES (EES), peripheral primitive neuroectodermal tumor of bone (pPNET), and malignant small-cell tumor of the thoracopulmonary region, or Askin's tumor, all of which are now known to be neoplasms of neuroectodermal origin. The degree of neuronal differentiation has been used for histopathologic subclassification of the EFT as classical ES (ESB or EES), which is characterized by minimal evidence of neural differentiation, and pPNET, which displays evidence of neural differentiation by standard microscopy, electron microscopy, or immunohistochemistry. Because the behavior, prognosis, and treatment appear to be similar for all subsets of EFT, this histopathologic subclassification may not be clinically significant, though some debate remains whether neural differentiation predicts for inferior outcome.

High-dose therapy with autologous stem cell rescue for pediatric sarcomas

PURPOSE OF REVIEW

The principal pediatric sarcomas are Ewing sarcoma, rhabdomyosarcoma, and osteosarcoma. While the prognosis for these diseases is generally favorable, it is possible to identify groups of patients with each diagnosis whose prognosis remains unacceptably poor. Based on the chemotherapy sensitivity of these tumors, many investigators have suggested that consolidation with high dose chemotherapy with or without radiation therapy followed by stem cell rescue could improve the prognosis for these high risk patients. This review evaluates the results of high dose therapy with stem cell reconstitution used to consolidate treatment of high risk patients with sarcomas.

RECENT FINDINGS

The majority of the trials which have been conducted to assess this hypothesis have treated relatively small numbers of patients. They do not use consistent definitions of high risk. They have used different regimens for cytoreduction. They have used a variety of sources for stem cells. In many series, the consolidation therapy is applied only to patients who have achieved a significant response to prior therapy and the results have then been compared to a cohort of patients with similar presenting features, not all of whom responded to initial therapy.

SUMMARY

The published results do not demonstrate an unequivocal benefit for consolidation with high-dose therapy. Future trials of high-dose therapy must define rigorous eligibility criteria, must have an appropriate, preferably randomized, control group, and must be designed with sufficient power to evaluate the hypothesis.

High-dose melphalan, etoposide, total-body irradiation, and autologous stem-cell reconstitution as consolidation therapy for high-risk Ewing's sarcoma does not improve prognosis

PURPOSE

To determine whether consolidation therapy with high-dose melphalan, etoposide, and total-body irradiation (TBI) with autologous stem-cell support would improve the prognosis for patients with newly diagnosed metastatic Ewing's sarcoma (ES).

PATIENTS AND METHODS

Thirty-two eligible patients with newly diagnosed ES metastatic to bone and/or bone marrow were enrolled onto this study. Treatment was initially comprised of five cycles of induction chemotherapy (cyclophosphamide, doxorubicin, and vincristine alternating with ifosfamide and etoposide) and local control. Peripheral-blood stem-cell collection was performed after the second cycle of chemotherapy, with delay if the bone marrow was persistently involved. If patients had a good response to initial therapy, they proceeded to consolidation therapy with melphalan, etoposide, TBI, and stem-cell support.

RESULTS

Of the 32 eligible patients, 23 proceeded to high-dose therapy consolidation. Of the nine patients who did not proceed to consolidation, four were secondary to progressive disease and two were secondary to toxicity. Three patients died from toxicity during the high-dose phase of the therapy. The majority of the patients who underwent high-dose consolidation therapy experienced relapse and died with progressive disease. Two-year event-free survival (EFS) for all eligible patients is 20%. The 2-year post-stem-cell reconstitution EFS for the subset of 23 patients who received consolidation therapy is 24%. Analysis of peripheral-blood stem-cell collections by molecular techniques for minimal residual disease showed contamination of at least some samples by tumor cells in all three patients with available data.

CONCLUSION

Consolidation with high-dose melphalan, etoposide, TBI, and autologous stem-cell support failed to improve the probability of EFS in this cohort of patients with newly diagnosed metastatic ES.

Long-term haematological recovery following high-dose chemotherapy with autologous bone marrow transplantation or peripheral stem cell transplantation in patients with solid tumours

long-term peripheral blood counts and factors influencing long-term trilineage haematological recovery of consecutive patients in a single institution treated with high-dose chemotherapy (hdc) and abmt or psct for solid tumours were examined. patients with a relapse-free survival of >1 year were included in the analysis (n = 131). Peripheral blood counts were examined 6 months and yearly following transplantation. Median follow-up was 4.1 years (range 1-10+ years). Three years after transplantation 91% of patients had normal white blood counts (WBC), 94% normal haemoglobin (Hb) and 75% normal platelets. Trilineage recovery was complete in 70% (n = 83) at 3 years and 85% (n = 50) at 5 years. Recovery of Hb occurred before WBC and platelet recovery. Approximately 25% of patients displayed an elevated MCV throughout the follow-up period. These long-term results were independent of age, high-dose regimen, number of reinfused stem cells and stem cell source. Double (n = 12) vs single (n = 119) transplantations showed significantly slower trilineage recovery and higher MCV. No secondary graft failure, myelodysplasia or leukaemia was encountered. In conclusion, complete trilineage recovery after HDC followed by ABMT or PSCT occurs slowly. PSCT and ABMT are capable of maintaining long-term haematopoiesis. Slower recovery is seen after double transplantations. The results suggest lasting implications for bone marrow function after autologous transplantation.

How effective is dose-intensive/myeloablative therapy against Ewing's sarcoma/primitive neuroectodermal tumor metastatic to bone or bone marrow? The Memorial Sloan-Kettering experience and a literature review

PURPOSE

Attempts to improve outcomes of patients with Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) metastatic to bone/bone marrow (BM) have focused on chemotherapy dose intensification strategies. We now present results achieved with that approach, as carried out at Memorial Sloan-Kettering Cancer Center (MSKCC) and as reported in the literature.

PATIENTS AND METHODS

Twenty-one unselected MSKCC patients with newly diagnosed ES/PNET metastatic to bone/BM received the "P6" protocol which includes cycles of cyclophosphamide (4.2 g/m(2))/doxorubicin (75 mg/m(2))/vincristine and cycles of ifosfamide (9 g/m(2))/etoposide (500 mg/m(2)). Patients in complete/very good partial remission (CR/VGPR) after P6 received myeloablative therapy with either total-body irradiation (TBI) (hyperfractionated 15 Gy)/melphalan (180 mg/m(2)) or thiotepa (900 mg/m(2))/carboplatin (1,500 mg/m(2)). We reviewed the literature.

RESULTS

Only one MSKCC patient became a long-term event-free survivor; all but one relapse was in a distant site. Initial responses to P6 were CR/VGPR in 19 patients, but eight of them plus two others developed PD while receiving or shortly after completing P6. Eight patients were treated with TBI/melphalan: four relapsed 2 to 7 months after transplantation; two died early of toxicity; one died of pulmonary failure 17 months after transplantation (no evidence of ES/PNET); and one remains in CR at more than 7 years. The three patients treated with thiotepa/carboplatin relapsed 3 to 4 months after transplantation. All reports on large series of unselected patients with ES/PNET metastatic to bone/BM showed similarly unsatisfactory results. Poor outcome was seen with use of active agents for ES/PNET-cyclophosphamide, ifosfamide, doxorubicin, dactinomycin, vincristine, etoposide - at standard dosages for prolonged periods of time and at higher dosages in intensive regimens for short or prolonged periods of time. No improvements in event-free survival rates occurred with successive cooperative group or large single-institutional studies that used increasingly aggressive chemotherapeutic approaches. Inclusion of ifosfamide with or without etoposide made no difference nor did consolidation of remission with myeloablative chemoradiotherapy. Secondary leukemia emerged as a major risk with dose-intensive regimens.

CONCLUSION

The MSKCC experience and findings reported in the literature suggest that dose-intensive use of the chemotherapy agents with established activity against ES/PNET is reaching its efficacy and toxicity limits. A major impact on prognosis awaits the development of entirely novel therapies.