External quality assessment slide schemes: pathologists' experiences and perceptions.

BACKGROUND: External quality assessment schemes (EQAS) in pathology have been established in the United Kingdom for several years with the aim of raising standards. OBJECTIVE: To determine the experiences and perceptions of pathologists undertaking EQAS. METHODS: A questionnaire was distributed to histo/cytopathologists in the south and west of England. RESULTS: A large proportion of pathologists responding felt that the EQAS was educational, and 69% said participation had encouraged them to undertake additional educational activities. Some reservations were expressed about marking schemes. Asked if EQAS using digital images (CD-ROM or web based) rather that glass slides were valid alternatives two thirds responded no, despite 75% claiming to have appropriate IT skills. CONCLUSIONS: EQAS play a valuable role in helping to maintain standards in histopathology and cytopathology. Some reservations were expressed about the marking schemes and further work is needed to establish a robust marking method. Significant barriers need to be overcome if digital EQAS are to be successfully implemented.

The NHS breast screening programme (pathology) EQA: experience in recent years relating to issues involved in individual performance appraisal.

BACKGROUND: The original role of the National Health Service breast screening programme (pathology) external quality assessment (EQA) scheme was educational; it aimed to raise standards, reinforce use of common terminology, and assess the consistency of pathology reporting of breast disease in the UK. AIMS/METHODS: To examine the performance (scores) of pathologists participating in the scheme in recent years. The scheme has evolved to help identify poor performers, reliant upon setting an acceptable cutpoint. Therefore, the effects of different cutpoint strategies were evaluated and implications discussed. RESULTS/CONCLUSIONS: Pathologists who joined the scheme improved over time, particularly those who did less well initially. There was no obvious association between performance and the number of breast cancer cases reported each year. This is not unexpected because the EQA does not measure expertise, but was established to demonstrate a common level of performance (conformity to consensus) for routine cases, rather than the ability to diagnose unusual/difficult cases. A new method of establishing cutpoints using interquartile ranges is proposed. The findings also suggest that EQA can alter a pathologist's practice: those who leave the scheme (for whatever reason) have, on average, marginally lower scores. Consequently, with the cutpoint methodology currently used (which is common to several EQA schemes) there is the potential for the cutpoint to drift upwards. In future, individuals previously deemed competent could subsequently be erroneously labelled as poor performers. Due consideration should be given to this issue with future development of schemes.

Impact of a national external quality assessment scheme for breast pathology in the UK.

BACKGROUND: This article presents the results and observed effects of the UK National Health Service Breast Screening Programme (NHSBSP) external quality assurance scheme in breast histopathology. AIMS/METHODS: The major objectives were to monitor and improve the consistency of diagnoses made by pathologists and the quality of prognostic information in pathology reports. The scheme is based on a twice yearly circulation of 12 cases to over 600 registered participants. The level of agreement was generally measured using kappa statistics. RESULTS: Four main situations were encountered with respect to diagnostic consistency, namely: (1) where consistency is naturally very high-this included diagnosing in situ and invasive carcinomas (and certain distinctive subtypes) and uncomplicated benign lesions; (2) where the level of consistency was low but could be improved by making guidelines more detailed and explicit-this included histological grading; (3) where consistency could be improved but only by changing the system of classification-this included classification of ductal carcinoma in situ; and (4) where no improvement in consistency could be achieved-this included diagnosing atypical hyperplasia and reporting vascular invasion. Size measurements were more consistent for invasive than in situ carcinomas. Even in cases where there is a high level of agreement on tumour size, a few widely outlying measurements were encountered, for which no explanation is readily forthcoming. CONCLUSIONS: These results broadly confirm the robustness of the systems of breast disease diagnosis and classification adopted by the NHSBSP, and also identify areas where improvement or new approaches are required.

Monoclonal antibodies to the myogenic regulatory protein MyoD1: epitope mapping and diagnostic utility.

Monoclonal antibodies (MoAbs) were developed against recombinant wild-type murine MyoD1 protein. Each of 4 MoAbs was immunologically reactive with recombinant MyoD1 protein by enzyme-linked immunosorbent assay, and each specifically stained the nuclei of myogenic cells. Epitopes were mapped using fusion protein constructs with specific deletions of defined regions of the MyoD1 molecule. MoAb 5.2F recognized an epitope in the amino terminal region between amino acid residues (AAR) 3 and 56, whereas epitopes for MoAbs 1.1A, 5.4G, and 5.8A were in the carboxyl terminus (AAR 167-318) of the MyoD1 protein. The epitope for MoAb 5.8A was further delineated to AAR 170-209 by Western analysis and immunoprecipitation of in vivo transcribed and translated MyoD1 protein having specific deletions in the carboxyl terminus. The 5.8A epitope was ultimately localized to the region between AAR 180 and 189 of the protein by enzyme-linked immunosorbent assay using 10-amino acid residue synthetic peptides. This sequence is apparently unique to MyoD1 and has little homology to other myogenic regulatory proteins (myogenin, Myf5, Myf6, and MRF4). Transfection of cDNA for murine MyoD1 into a nonmuscle cell line conferred 5.8A reactivity, confirming the specificity of this reagent. MoAb 5.8A was then used to examine the expression of MyoD1 in normal and malignant human tissues. MyoD1 was not detected in any normal adult tissue but was detected in 25 of 25 histologically confirmed rhabdomyosarcomas. Staining was localized to the nucleus and showed marked heterogeneity between cells as well as differential staining within nuclei. Specific subcellular localization of 5.8A was further determined by immunoelectron microscopy, where antibody was found to localize to electron-dense areas, more frequently associated with the nuclear submembranous region. In addition to rhabdomyosarcomas, MoAb 5.8A stained 2 of 5 Wilms' tumors and one ectomesenchymoma, neoplasms known to contain myogenic elements. The 5.8A reagent was also of value in the accurate histopathological classification of 2 of 4 tumors previously diagnosed as extraosseous Ewing's sarcoma and 2 of 3 tumors diagnosed as undifferentiated sarcomas.

Inhibition of the interferon-gamma/signal transducers and activators of transcription (STAT) pathway by hypermethylation at a STAT-binding site in the p21WAF1 promoter region.

Expression of the cyclin-dependent kinase inhibitor p21WAF1 can be up-regulated by activation of signal transducers and activators of transcription (STAT) proteins in response to IFN-gamma. In this study, we examined CpG methylation at the p21WAF1 promoter region in rhabdomyosarcomas (RMSs) using Southern blot analysis with the methylation-sensitive restriction enzyme HpaII. Sis-inducible element (SIE)-1, a STAT-responsive element located upstream of the p21 WAF1 CpG island, was completely methylated at an internal CpG in 13 of 26 (50%) primary RMS tumors and 2 of 5 RMS cell lines. In contrast, all normal tissues examined showed a partial methylation pattern at SIE-1. Complete methylation within SIE-1 strongly correlated with decreased p21WAF1 mRNA expression in RMS. We further studied the effects of SIE-1 hypermethylation on p21WAF1 induction by STAT activation. CpG methylation within SIE-1 significantly inhibited binding of activated STAT1 in electrophoretic mobility shift assays and abrogated STAT-mediated transcription activation in response to IFN-gamma in luciferase reporter gene assays. Activation of STAT1 in response to IFN-gamma resulted in increased p21WAF1 expression and growth suppression in RMS cells containing unmethylated SIE-1 but failed to induce p21WAF1 or growth inhibition in RD and A673 cells, both of which were completely methylated within SIE-1. However, demethylation at SIE-1, induced by a demethylating agent 5-aza-2'-deoxycytidine, reactivated p21WAF1 expression and restored the responsiveness to IFN-gamma in RD cells. Our results indicate a mechanism by which altered DNA methylation in the p21 WAF1 promoter region, by precluding STAT1 binding to SIE-1, directly inhibits the p21WAF1 induction and cell growth regulation through the IFN-gamma/STAT signaling pathway in RMS cells.

Development and characterization of human ependymoma xenograft HxBr5.

We describe the successful heterotransplantation of a human ependymoma in CBA/CaJ mice immune deprived by infant thymectomy and whole-body irradiation. The xenograft, HxBr5, was established from a fourth ventricular ependymoma, locally recurrent in an 11-yr-old girl who had been treated with radiation therapy to the posterior fossa. HxBr5 retains histological and ultrastructural fidelity to the tumor from which it was derived as does the DNA content, as confirmed by flow cytometric analysis. The karyotype of the xenograft, which is pseudodiploid and exhibits trisomy 1q and deletion of 1p, is the first human ependymoma banded karyotype to be reported. Growth rates of the xenograft tumors are similar to the primary tumor as clinically observed with a doubling time of approximately 42 days. Cell kinetic parameters indicate that this slow-growing tumor has a relatively high growth fraction of 70.8% with a high cell loss of approximately 91%. We anticipate that HxBr5 may be useful as one component of a more complex model for studying the biology and differentiation of human ependymoma.

Characterization of cell lines derived from xenografts of childhood rhabdomyosarcoma.

Three human rhabdomyosarcoma cell lines (Rh10, Rh18, and Rh28) have been established from three independently derived xenografts. These lines have been characterized as mesenchymal in origin (reactivity to desmin and vimentin antibodies) and as expressing a human fetal muscle surface antigen recognized by monoclonal antibody 5.1 H11. Measurable levels of creatine phosphokinase have been detected in the cell lines. Rh10 and Rh28 exhibit the same chromosomal translocation and express an atypical lactate dehydrogenase isoenzyme which may be homologous to those previously reported in other tumor types. The karyotype analysis has confirmed that each cell line was derived from its respective tumor and thus provides a unique model for future investigations.

Methods to detect P-glycoprotein-associated multidrug resistance in patients' tumors: consensus recommendations.

Multidrug resistance (MDR), especially that associated with overexpression of MDR1 and its product, P-glycoprotein (Pgp), is thought to play a role in the outcome of therapy for some human tumors; however, a consensus conclusion has been difficult to reach, owing to the variable results published by different laboratories. Many factors appear to influence the detection of Pgp in clinical specimens, including its low and heterogeneous expression; conflicting definitions of detection end points; differences in methods of sample preparation, fixation, and analysis; use of immunological reagents with variable Pgp specificity and avidity and with different recognition epitopes; use of secondary reagents and chromogens; and differences in clinical end points. Also, mechanisms other than Pgp overexpression may contribute to clinical MDR. The combined effect of these factors is clearly important, especially among tumors with low expression of Pgp. Thus, a workshop was organized in Memphis, Tennessee, to promote the standardization of approaches to MDR1 and Pgp detection in clinical specimens. The 15 North American and European institutions that agreed to participate conducted three preworkshop trials with well-characterized MDR myeloma and carcinoma cell lines that expressed increasing amounts of Pgp. The intent was to establish standard materials and methods for a fourth trial, assays of Pgp and MDR1 in clinical specimens. The general conclusions emerging from these efforts led to a number of recommendations for future studies: (a) although detection of Pgp and MDR1 is at present likely to be more reliable in leukemias and lymphomas than in solid tumors, accurate measurement of low levels of Pgp expression under most conditions remains an elusive goal; (b) tissue-specific controls, antibody controls, and standardized MDR cell lines are essential for calibrating any detection method and for subsequent analyses of clinical samples; (c) use of two or more vendor-standardized anti-Pgp antibody reagents that recognize different epitopes improves the reliability of immunological detection of Pgp; (d) sample fixation and antigen preservation must be carefully controlled; (e) multiparameter analysis is useful in clinical assays of MDR1/Pgp expression; (f) immunostaining data are best reported as staining intensity and the percentage of positive cells; and (g) arbitrary minimal cutoff points for analysis compromise the reliability of conclusions. The recommendations made by workshop participants should enhance the quality of research on the role of Pgp in clinical MDR development and provide a paradigm for investigations of other drug resistance-associated proteins.

The Evi-1 zinc finger myeloid transforming gene is normally expressed in the kidney and in developing oocytes.

Activation of the Evi-1 zinc finger gene is commonly associated with the transformation of murine leukemias and is involved in some cases of human AML involving rearrangements at chromosome 3q25. To determine the normal function of the gene, we have looked for expression in a variety of cell lines and tissues. The predominant sites of expression of the gene are in the kidney and ovary. In the kidney, expression is localized to the renal tubules in the corticomedullary junction. In the ovary, high levels of the Evi-1 protein are found in the cytoplasm of developing oocytes. The latter result suggests a potential role for the Evi-1 gene product in early oocyte development.

Metastatic Ewing's sarcoma: remission induction and survival.

Eighteen patients with previously untreated metastatic Ewing's sarcoma (ES) entered a protocol designed to evaluate the response rate to cyclophosphamide and doxorubicin induction therapy delivered before delayed surgery and delayed lower dose, limited-field radiation therapy, (RT), and maintenance chemotherapy. With chemotherapy and delayed surgery, 14 of 18 were rendered free of gross tumor. RT was delivered to the primary site of 11 of these responding patients, plus four of those not free of gross disease. Following RT, two more attained complete clinical remission. Site of primary or metastases did not influence outcome; however, the size of the primary at diagnosis did appear to do so. Ten patients remain disease-free 16 to 82 months (median, 47 months) from diagnosis.

Relationship of tumor-cell ploidy to histologic subtype and treatment outcome in children and adolescents with unresectable rhabdomyosarcoma.

Clinical and histopathologic features are often inadequate for accurate prediction of relapse or survival of individual patients with rhabdomyosarcoma (RMS). We therefore studied the cellular DNA content (ploidy) of RMS cells in relation to histology and response to therapy in 37 patients with unresectable tumors. Using flow cytometric techniques, we found that about one third of patients had diploid tumor stem lines, regardless of the histologic subtype. In the group with abnormal ploidy, a hyperdiploid classification (1.10 to 1.80 times the DNA content of normal diploid cells) was exclusively associated with embryonal histology (P = .001). By contrast, near-tetraploidy (1.80 to 2.60 times the DNA content of normal cells) was strongly associated with alveolar histology (P = .001). Thus, in these histologic subtypes of RMS, abnormal ploidy appears to arise through different mechanisms. Tumor-cell ploidy had a significant impact on survival that was especially apparent in patients with unresectable, nonmetastatic (group III) tumors. In this subgroup, hyperdiploidy conferred the best prognosis and diploidy the worst (P less than .0001). None of the eight patients with diploid tumors survived for more than 18 months. Tumor-cell ploidy was the best predictor of treatment outcome for patients with either embryonal (P less than .001; relative risk, 25.5) or alveolar (P = .073; relative risk 7.1) RMS and contributed significantly after adjustment for disease stage and anatomic site. Patients with unresectable diploid RMS have an unacceptably high risk of treatment failure, justifying new therapeutic approaches for this distinct subgroup.

Reduced therapy for Wilms' tumor: analysis of treatment results from a single institution.

From 1968 to 1986, 192 patients from 0 to 17 years of age were enrolled in three consecutive protocol-controlled studies of Wilms' tumor at St Jude Children's Research Hospital. Tumors were completely excised at the time of diagnosis whenever possible, and patients were subsequently treated with chemotherapy and radiotherapy according to the initial extent of disease. All patients received dactinomycin and vincristine, with doxorubicin added to the regimens in studies 2 and 3. Chemotherapy was extended to 18 months in study 2 (n = 53), but was limited to 12 months for most patients in study 3 (n = 107). In the third study, radiation was eliminated altogether for patients with stage I or II tumors and was reduced to 12 Gy for those with more advanced disease. Intensification of chemotherapy in study 2 improved the 5-year relapse-free survival rate over that in study 1 (82% v 52%), but the accompanying increase in toxicity was considered unacceptable. Comparison of 2-year relapse-free survival rates in studies 2 and 3 indicated that the reduction of therapy in the latter trial did not jeopardize disease control: 88% v 86% for patients with stage II or III disease, favorable histology; 75% v 57% for the same stages, unfavorable histology; and 57% v 61% for stage IV patients. At least 80% of all patients enrolled in study 3 will be long-term survivors. We conclude that rescheduling of effective antitumor drugs and eliminating or reducing radiotherapy are feasible alternatives in the treatment of Wilms' tumor with favorable histologic features.

Hyperdiploidy and chromosomal rearrangements define the anaplastic variant of Wilms' tumor.

Flow cytometric measurement of the DNA content of Wilms' tumor cells revealed a striking correspondence with the histologic subtype and treatment outcome. In the 48 cases studied, a hyperdiploid DNA content ranging from 1.7 to 3.2 times the result for normal diploid cells distinguished all but one of the ten anaplastic tumors. Lower values, from 1.0 to 1.4 times the diploid DNA content, characterized the nonanaplastic specimens. By Kaplan-Meier analysis, the probability of achieving 3 years of relapse-free survival was significantly lower in the group with higher DNA content (0.42 v 0.87, P less than .01). Analysis of banded chromosomes for a subset of 22 patients contributed important information beyond the flow cytometric study. Cases of anaplasia associated with poorer responses to therapy showed numerous complex translocations, whereas all others lacked such changes. By combining flow cytometric techniques and conventional methods of chromosome analysis, it should be possible to identify those patients with Wilms' tumor who are most likely to fail therapy. The biologic implication of these findings is that the development of clinical drug resistance in Wilms' tumor is a result of the genetic instability of the malignant clone.

Ifosfamide plus etoposide in newly diagnosed Ewing's sarcoma of bone.

PURPOSE: We assessed the activity of ifosfamide plus etoposide against newly diagnosed Ewing's sarcoma of bone by administering this drug pair before standard induction therapy (the upfront window approach). PATIENTS AND METHODS: Twenty-six children and adolescents with newly diagnosed, previously untreated Ewing's sarcoma of bone were enrolled onto this pilot study (EW-87). Eighteen were at a higher risk of treatment failure, with a primary tumor size of more than 8 cm or metastases at diagnosis. Window therapy with ifosfamide (1.6 g/m2/d with mesna uroprotection) and etoposide (100 mg/m2/d) was given in three 5-day cycles at 21-day intervals. Responses were evaluated clinically and radiologically. Subsequent induction therapy comprised three cycles of cyclophosphamide and doxorubicin. Radiation therapy was the primary local control modality; surgery was limited to biopsy or resection of expendable bones. After the local control phase, alternating courses of vincristine plus dactinomycin, ifosfamide plus etoposide, and cyclophosphamide plus doxorubicin were given as maintenance therapy. RESULTS: There were four complete responses and 21 partial responses to ifosfamide/etoposide window therapy (overall response rate 96%; 95% confidence interval [CI], 80% to 99%). Disease progression was observed in four patients during the cyclophosphamide/doxorubicin phase. Chemotherapy was well tolerated; only 16% (20 of 125) of all ifosfamide/etoposide window and maintenance cycles resulted in hospitalization for fever and neutropenia. Two patients developed chemotherapy-induced cystitis. CONCLUSIONS: The combination of ifosfamide and etoposide is highly active against previously untreated Ewing's sarcoma and generally is well tolerated. The ultimate impact of these two agents on outcome will be determined in randomized multicenter studies.

Synovial sarcoma in children and adolescents: the St Jude Children's Research Hospital experience.

PURPOSE AND METHODS: We reviewed the clinical records and pathologic findings of 37 children and adolescents with synovial sarcoma treated at our institution over a 30-year period to evaluate the prognostic significance of tumor size, invasiveness, histology, and other features. RESULTS: The 20 male and 17 female patients with synovial sarcoma had a median age of 13.7 years at diagnosis. Primary tumor sites were the extremities (n = 27), trunk (n = 8), and head and neck (n = 2). Disease stage (clinical group) was as follows: group I, n = 21; group II, n = 7; group III, n = 4; and group IV, n = 5. Nineteen patients had invasive (T2) lesions, 20 had tumors more than 5 cm in diameter, and 14 had histologic grade 3 lesions. The estimated 5-year survival rate (+/- SE) for patients with group I or II disease was 80% +/- 9%, compared with 17% +/- 15% for those with group III or IV tumors (P = .0003). An exact log-rank test, adjusted for clinical group, showed that tumor invasiveness and grade independently predicted overall and progression-free survival (P < .05); tumor size was significantly correlated with progression-free survival. A borderline significant relationship with overall survival was found for both tumor size and histologic subtype (P = .09). CONCLUSION: A controlled trial of adjuvant chemotherapy is merited in children with resected synovial sarcoma (clinical group I or II) who present with unfavorable clinicopathologic features such as large, invasive, or grade 3 lesions. Children with unresected or metastatic disease fare poorly despite multimodality therapy and require novel treatment approaches.

Chemotherapy dose-intensification for pediatric patients with Ewing's family of tumors and desmoplastic small round-cell tumors: a feasibility study at St. Jude Children's Research Hospital.

PURPOSE: To evaluate the feasibility of dose-intensification for patients with Ewing's family of tumors (EFT) and desmoplastic small round-cell tumors. PATIENTS AND METHODS: From February 1992 to June 1996, we treated 53 consecutive patients on our Ewing's protocol. Induction comprised three cycles of ifosfamide/etoposide on days 1 to 3 and cyclophosphamide (CTX)/doxorubicin on day 5, followed by granulocyte colony-stimulating factor. Local control using surgery and/or radiotherapy started at week 9 along with vincristine/dactinomycin. Maintenance included four alternating cycles of ifosfamide/etoposide and doxorubicin/CTX, with randomization to one of two CTX dose levels to determine the feasibility of dose-intensification during maintenance. RESULTS: Patients had a median age of 13.4 years (range, 4.5 to 24.9 years); 34 patients were male and 43 patients were white. Nineteen patients presented with metastatic disease, 29 had tumors greater than 8 cm in diameter, and 26 had primary bone tumors. These patients received 155 induction cycles, 91% of which resulted in grade 4 neutropenia, 68% in febrile neutropenia, and 68% in grade 3 to 4 thrombocytopenia. During maintenance, grade 4 neutropenia and grade 3 to 4 thrombocytopenia occurred in 81% and 85% of cycles, respectively. Thirty-five patients (66%) completed all therapy, only 13 without significant delays; three developed secondary myeloid malignancies. The toxicity and time to therapy completion were similar in both CTX arms. Estimated 3-year survival and event-free survival were 72%+/-8% and 60%+/-9%, respectively. CONCLUSION: Although intensifying therapy seems feasible for 25% of patients on this study, toxicity was considerable. Therefore, the noninvestigational use of dose-intensification in patients with EFT should await assessment of its impact on disease-free survival.

Role of adjuvant chemotherapy in the treatment of surgically resected pediatric nonrhabdomyosarcomatous soft tissue sarcomas: A Pediatric Oncology Group Study.

PURPOSE: To prospectively study the value of adjuvant chemotherapy in pediatric patients with surgically resected nonrhabdomyosarcomatous soft tissue sarcomas (NRSTS). PATIENTS AND METHODS: From June 1986 to May 1992, after complete surgical resection (+/-radiotherapy) of their NRSTS, 81 eligible patients either received adjuvant chemotherapy comprising vincristine, dactinomycin, cyclophosphamide, and doxorubicin or were observed. Only 30 patients accepted randomization, and 15 were assigned to each regimen. Of the remaining 51 patients, 19 elected adjuvant chemotherapy and 32 elected observation. RESULTS: Patients were predominantly male, and 69% of all patients were white. The median age at diagnosis was 12.3 years (range, 9.2 to 20.7 years). For the 81 eligible patients, the 5-year overall survival estimate was 84.5% +/- 4.4% and event-free survival was 72.2% +/- 5.4%. Among randomized patients, the 5-year estimated overall survival rate was 93.3% +/- 7%, and the event-free survival rate was 86.7% +/- 9.5% for the observation group, compared with 69.2% +/- 13% and 40.7% +/- 14%, respectively, for those who received chemotherapy. The significantly worse outcome of patients who received adjuvant chemotherapy disappeared when survival was stratified by tumor grade. Among all patients, a grade 3 lesion conferred a significant disadvantage with respect to event-free survival (P =.0001). CONCLUSION: The administration of adjuvant chemotherapy according to the schedule and dosages used in our trial did not improve the outcome of children with resected NRSTS. In this study, tumor grade was the most important predictor of clinical outcome in patients with resected NRSTS, and this factor should be incorporated into the stratification of patients in future trials.

Therapy for localized Ewing's sarcoma of bone.

Fifty-two previously untreated patients with localized Ewing's sarcoma of bone were treated with nonintensive chemotherapy in combination with surgery or radiation therapy (RT). RT was delivered to limited volumes in a dose dependent on the initial response to induction chemotherapy (30 to 35 Gy v 50 to 55 Gy). Fifty of the 52 patients achieved complete or partial responses with induction chemotherapy, with one nonresponding patient rendered free of tumor with surgery. Fifty patients were evaluable for local control of tumor and overall response to protocol therapy. Seventeen relapses have occurred; three metastatic, four local plus metastatic, and ten local. Two factors predicted worse disease-free survival: high WBC count (P = .03) and size of primary tumor (P = .05). Of the 14 local recurrences, 12 occurred in 28 patients who presented with primary tumors greater than 8 cm in size while only two of 22 patients with lesions less than 8 cm had local recurrence. The Kaplan-Meier estimate of disease-free survival at 3 years is 82% for those with small lesions and 64% for those with larger lesions. Site of primary was of no prognostic value (P = .27). The 5-year survival estimate for all patients is 80% (median time on study, 3.3 years).

P-glycoprotein expression at diagnosis may not be a primary mechanism of therapeutic failure in childhood rhabdomyosarcoma.

PURPOSE: To evaluate the prognostic significance of tumor cell P-glycoprotein (Pgp) expression at diagnosis in children with rhabdomyosarcoma. PATIENTS AND METHODS: A panel of three anti-Pgp monoclonal antibodies (mAb) (C219, C494, and JSB-1) that recognize different Pgp epitopes was used to measure Pgp expression in rhabdomyosarcoma specimens obtained at diagnosis from 76 patients treated at St Jude Children's Research Hospital from 1969 to 1991. Two separate experiments using different immunohistochemical methods (immune alkaline phosphatase and immunoperoxidase) were performed to evaluate Pgp expression. The immunostaining was graded using a semiquantitative scale corresponding to the percentage of tumor cells with detectable staining. The influence of Pgp expression on outcome was assessed by the Kaplan-Meier method and Cox regression analysis with stepwise selection. The relationship between Pgp expression and clinical features was assessed using the Mantel-Haenszel method. RESULTS: Pgp expression at diagnosis did not predict worse overall survival or progression-free survival when tested in either experiment with C219, C494, or JSB-1 separately. No association was shown between Pgp expression and clinical features (clinical group, primary site, or histology) or response. However, in the immune alkaline phosphatase experiment, patients whose tumors had more than 10% tumor cell staining with all three mAbs had a significantly higher rate of estimated 5-year survival (78% +/- 10%) than did all other patients (38% +/- 8%; P = .025). In this instance, Pgp expression had independent prognostic value after adjusting for clinical group. CONCLUSION: We found no strong association between Pgp expression at diagnosis and clinical features or extent of disease in pediatric rhabdomyosarcoma. Depending on the criteria used to define it, high Pgp expression at diagnosis does not predict poor outcome. Although a large prospective study is needed to provide definitive conclusions, our findings suggest that Pgp-mediated multidrug resistance may not be a primary mechanism of therapeutic failure in rhabdomyosarcoma.

Impact of intensified therapy on clinical outcome in infants and children with neuroblastoma: the St Jude Children's Research Hospital experience, 1962 to 1988.

To gauge the impact of intensified therapy on the survival of infants (younger than 1 year, n = 129) and children (greater than or equal to 1 year of age, n = 275) with neuroblastoma, we analyzed the results of eight successive clinical trials comparing various combinations of antineoplastic drugs, surgery, and radiotherapy. Changes in treatment did not affect the survival of children with involved noncontiguous lymph nodes or distant metastatic disease until the combination of cisplatin and teniposide (CDDP/VM26) was added to a basic regimen of cyclophosphamide and doxorubicin (CTX/DOX). The resulting 4-year survival was 28% +/- 5% (SE) compared with 7% +/- 2% for previous treatments (P less than .001 by the log-rank test). The 4-year survival of infants with metastatic disease was improved by administering CTX/DOX to all patients, reserving CDDP/VM26 for those whose disease was resistant to the former combination: 82% +/- 6% versus 45% +/- 8% in earlier studies; P less than .001. In the subset of infants whose tumors had disseminated to bone or bone marrow at diagnosis, this therapeutic approach increased the probability of long-term survival from 48% +/- 10% to 85% +/- 9% (P = .01). The small group of children over 1 year of age with localized unresectable tumors also fared significantly better with the switch to CTX/DOX chemotherapy (4-year survival, 93% +/- 7% v 42% +/- 13%; P = .02). Multivariate analysis indicated that young age, limited-disease stage, nonadrenal primary site, and intensified treatment were independent predictors of a more favorable outcome. We conclude that substantial advances in the treatment of neuroblastoma have occurred over the past 25 years at this institution. The current overall 4-year survival probability of 57% +/- 4% compares favorably with estimates for most other common solid tumors of childhood.