Secondary leukemia or myelodysplastic syndrome after treatment with epipodophyllotoxins

Long-term survivors with adult acute leukemia in complete remission: complications and return to work

For addressing, and eventually being able to predict and prevent, both disease-related complications and changes in social status in long-term acute leukemia survivors, the follow-up is the most important factor after treatment. To this end, we assessed the complications following the attainment of complete remission in adult acute leukemia patients and the changes in social status of patients surviving more than 5 years after disease onset. In our study population of 42 survivors, 24 (57.1%) suffered from various combinations of 18 types of identified complications including posttransfusion hepatitis, diabetes mellitus, and idiopathic osteonecrosis. Regarding fertility, 9 live births were recorded in this cohort, from 2 female patients and the partner of a male patient. Of these 42 long-term survivors, at the time of this report 48.5% were working full- or part-time, 9.0% were unemployed, 30.3% were homemakers, and 12.2% were retired.

Acute myeloid leukemia and myelodysplastic syndrome in children treated for cancer: comparison with primary presentation

There has not been a reported series of children with therapy-induced myelodysplastic syndrome/acute myeloid leukemia (tMDS/tAML) who were treated systematically. This paper describes 24 children with tMDS/tAML who were assigned randomly to standard- or intensive-timing induction on protocol CCG 2891. Presenting features and outcomes of those children were compared with those of 960 patients with de novo MDS (62 patients) or AML (898 patients). Children with tMDS/tAML were older at presentation (P =.015), had lower white blood cell counts (P =.01), and were more likely to have MDS (21% vs 7%) (P =.02) and trisomy 8 (P =.06). Fewer had hepatomegaly (P =.02), splenomegaly (P =.03), hepatosplenomegaly (P =.02), or classic AML translocations [t(8;21), t(15;17), 16q22; P =.02]. They had a poorer induction rate (50% vs 72%, P =.016), overall survival (26% vs 47% at 3 years, P =.007), and event-free survival (21% vs 39% at 3 years, P =.023). Disease-free survival after achieving remission was similar (45% vs 53%, P =.868). Children with tMDS/tAML who received intensive-timing induction had better outcomes than those who received standard-timing induction (overall survival 32% vs 0%, P =.54). In this study, the latency period to development of tMDS/tAML was the same for presumed alkylator-induced as for topoisomerase-induced myeloid leukemia. The findings of this study confirm that most children with tMDS/tAML have disease resistant to current therapies. Standard-timing induction appears less effective for this population.

Treatment of unfavorable childhood Hodgkin's disease with VEPA and low-dose, involved-field radiation

PURPOSE

Between January 1990 and April 1993, 56 pediatric patients with Hodgkin's disease were treated on a single-arm trial at three institutions with a regimen designed to maintain high cure rates while minimizing the potential late effects of treatment, such as infertility, second malignant neoplasms, and cardiopulmonary injury.

PATIENTS AND METHODS

The regimen used combined-modality therapy with six cycles of vinblastine, etoposide, prednisone, and doxorubicin (VEPA) chemotherapy and low-dose, involved-field radiation. Unfavorable features comprised bulky presentations of localized (stage I or II) disease or advanced (stage III or IV) Hodgkin's disease.

RESULTS

Of 56 patients enrolled, 26 (46%) had unfavorable presentations of stage I/II disease and 30 (54%) had advanced (stage III/IV) disease. Seventy-nine percent of the patients are alive without disease at a median follow-up time of 8.9 years from diagnosis. Nineteen patients had events at a median of 1.5 years (range, 0.4 to 7.9 years) from diagnosis; 17 patients relapsed, one died of cardiomyopathy, and one died of accidental injuries. Survival and event-free survival (EFS) estimates at 5 years for the entire cohort were 81.9% (SE, 5.2%) and 67.8% (SE, 6.3%), respectively. Five-year EFS by stage was 100% for stage I, 79.2% (SE, 8.3%) for stage II, 70% (SE, 14.5%) for stage III, and 49.5% (SE, 11.3%) for stage IV patients.

CONCLUSION

Combined-modality therapy with VEPA chemotherapy and low-dose, involved-field radiation is adequate for disease control of early-stage patients with unfavorable features, but it is inferior to other standard regimens for advanced-stage patients.

MLL-SEPTIN6 fusion recurs in novel translocation of chromosomes 3, X, and 11 in infant acute myelomonocytic leukaemia and in t(X;11) in infant acute myeloid leukaemia, and MLL genomic breakpoint in complex MLL-SEPTIN6 rearrangement is a DNA topoisomerase II cleavage site

We examined the MLL translocation in two cases of infant AML with X chromosome disruption. The G-banded karyotype in the first case suggested t(X;3)(q22;p21)ins(X;11)(q22;q13q25). Southern blot analysis showed one MLL rearrangement. Panhandle PCR approaches were used to identify the MLL fusion transcript and MLL genomic breakpoint junction. SEPTIN6 from chromosome band Xq24 was the partner gene of MLL. MLL exon 7 was joined in-frame to SEPTIN6 exon 2 in the fusion transcript. The MLL genomic breakpoint was in intron 7; the SEPTIN6 genomic breakpoint was in intron 1. Spectral karyotyping revealed a complex rearrangement disrupting band 11q23. FISH with a probe for MLL confirmed MLL involvement and showed that the MLL-SEPTIN6 junction was on the der(X). The MLL genomic breakpoint was a functional DNA topoisomerase II cleavage site in an in vitro assay. In the second case, the karyotype revealed t(X;11)(q22;q23). Southern blot analysis showed two MLL rearrangements. cDNA panhandle PCR detected a transcript fusing MLL exon 8 in-frame to SEPTIN6 exon 2. MLL and SEPTIN6 are vulnerable to damage to form recurrent translocations in infant AML. Identification of SEPTIN6 and the SEPTIN family members hCDCrel and MSF as partner genes of MLL suggests a common pathway to leukaemogenesis.

Second cancers in survivors of childhood cancer

More than 70% of children diagnosed with cancer can now be expected to be long-term survivors. However, the consequences of 'cure' might be considerable for the survivors of cancer: 60-70% of young adults who have survived childhood cancer will develop at least one medical disability as a result of their cancer or, more commonly, as a result of their therapy. Of these, the most devastating is a second cancer.

Assessment of chemotherapy-induced DNA damage in peripheral blood leukocytes of cancer patients using the alkaline comet assay

The alkaline comet assay was employed to assess the pre- and post-treatment levels of in vivo DNA damage in peripheral blood leukocytes of cancer patients. During the study all patients were given antineoplastic drugs, mainly as polychemotherapy. To quantify the DNA damage, two different comet parameters were evaluated: the tail length and the tail moment. Our results indicate marked interindividual variations between baseline DNA damage in peripheral blood leukocytes recorded among cancer patients prior to the chemotherapy. After intravenous administration of various antineoplastic drugs, a significantly increased level of DNA damage in all cancer patients compared to their pre-treatment values was recorded The highest level of DNA damage was seen following administration of 5-fluorouracil, adriamycin, and cisplatin (FAP protocol). The results indicate that administration of antineoplastic drugs in standard protocols is accompanied by significant DNA damage in peripheral blood leukocytes. In order to diminish the potential risks of developing second neoplasms, a continuous biomonitoring of cancer patients after the ending of chemotherapy becomes important. Despite their limitations, present results confirm the usefulness of the alkaline comet assay as a sensitive biomarker of exposure that enables rapid and simple detection of primary DNA damage in peripheral blood leukocytes of cancer patients. Together with standard cytogenetic endpoints, the comet assay provides a powerful technique for the routine detection of critical DNA lesions produced after administration of antineoplastic drugs in the clinical settings.

Potential role of hematopoietic stem cell transplantation in children with secondary acute lymphocytic leukemia

Secondary acute lymphocytic leukemias (ALL) are uncommon events in the pediatric patient population. There are few detailed reports on the laboratory characteristics and clinical course of patients with secondary lymphocytic leukemia. Historically, these patients have had a poor outcome. We report two patients treated at one institution who developed treatment-related secondary ALL. Both patients underwent hematopoietic stem cell transplantation, one with a compatible unrelated donor cord blood unit and one with an HLA-matched sibling donor bone marrow. One of the two patients survives disease-free 3 years after transplantation.

Long-term Results of a Phase I/II Study of High-Dose Thoracic Radiotherapy With Concomitant Cisplatin and Etoposide in Limited Stage Small-Cell Lung Cancer

This report presents the results from a Mayo Clinic initiated phase I/II study exploring a potentially more aggressive local and systemic approach for treatment of limited-stage small-cell lung cancer (LSSCLC). Five patients with LSSCLC received three cycles of induction cyclophosphamide, etoposide, and infusion cisplatin chemotherapy. This was followed by accelerated hyperfractionated thoracic radiotherapy (AHFTRT) consisting of 30 Gy given as 1.5-Gy fractions twice daily with a 2-week break and then the AHFTRT was repeated. The AHFTRT was given concomitantly with daily oral etoposide and daily intravenous cisplatin. Prophylactic cranial radiation was delivered with the AHFTRT. After completion of the AHFTRT, patients received 4 cycles of oral etoposide maintenance chemotherapy. Follow-up of patients was continued until death or a minimum of 42 months. Three patients had severe toxic responses. No patients completed the entire protocol because of toxicity or progression during treatment. Three patients completed the majority of the protocol except for the four cycles of maintenance etoposide. Four of five patients achieved a complete response. There were two recurrences within the irradiated field, and distant metastases developed in four patients. Acute nonlymphocytic leukemia developed in one patient, who died 2 months later. No patient completed the entire protocol, because of toxicity or progression; therefore, this protocol cannot be recommended for the treatment of LSSCLC.

DNA topoisomerases as targets for anticancer drugs

DNA topoisomerases are essential enzymes that regulate the conformational changes in DNA topology by catalysing the concerted breakage and rejoining of DNA strands during normal cellular growth. Over the past few years there has been considerable pharmacological interest in these enzymes because inhibitors of DNA topoisomerases represent a major class of anticancer drugs. This review highlights topoisomerase-targeting drugs that have shown promising anticancer activities. The mechanisms by which those drugs interfere with the catalytic cycles of type I and type II DNA topoisomerases and the factors involved in the development of resistance to these drugs are discussed.

Second malignancies after ewing tumor treatment in 690 patients from a cooperative German/Austrian/Dutch study

BACKGROUND

Ewing tumor treatment involves high cumulative doses of alkylating agents and topoisomerase inhibitors, drugs capable of inducing second cancers. We analyzed the second cancer risk in a large cohort of consistently treated patients.

PATIENTS AND METHODS

Six hundred ninety Ewing tumor patients were treated between 1992 and 1999 with local therapy and vincristine. doxorubicin, ifosfamide and/or cyclophosphamide, and antinomycin D, with or without etoposide as a randomized question. Second cancer incidences were estimated by competing risk analyses; standardized incidence ratios (SIR) in comparison to registry data were compiled.

RESULTS

After a median observation time of 56 months (32 months for survivors), 6 of 690 patients had developed second cancers: MDS/AML, two, ALL/NHL, two, squamous cell carcinoma, one, liposarcoma, one. SIR were increased 20-30 fold in comparison to the general population. The cumulative second cancer risk five years after diagnosis of the Ewing tumor was 0.0093 for the total group, zero for patients without etoposide, and 0.0118 with etoposide. Additional phase II high-dose therapy increased the risk to 0.0398 after five years.

CONCLUSIONS

The second cancder risk observed was in the range to be expected in cancer survivors. High-dose therapy, and less markedly, etoposide, may contribute to the overall second cancer risk.

Biology and therapy of secondary leukaemias

Secondary leukaemias are common, accounting for more than 40% of all patients with acute myeloid leukaemia (AML) or myelodysplastic syndrome (MDS). A clinical history of exposure to haematotoxins or radiation is helpful; however, many older patients are diagnosed with leukaemia with no antecedent history of exposure. These patients' disease show a remarkably similar phenotype to classic therapy-related leukaemia. The specific cytogenetic abnormalities common to MDS, alkylating-agent-related AML and poor-prognosis AML (3q-, -5, 5q-, -7, 7q-, +8, +9, 11q-, 12p-, -18, -19,20q-, +21, t(1;7), t(2;11)), probably reflect a common pathogenesis distinct from that of other de novo AMLs, although the pathogenetic pathway has yet to be elucidated. Possibly, tumour suppressor genes are implicated and genomic instability may be a cause of multiple unbalanced chromosomal translocations or deletions. Typically, these patients are either elderly or have a history of exposure to alkylating agents or environmental exposure 5-7 years prior to diagnosis. Another distinct entity affects the mixed lineage leukaemia (MLL) gene located on 11q23. These account for about 3% of patients with therapy-related leukaemia and have a short latency period from exposure, usually to an inhibitor of topoisomerase II. Other therapy-related patients with t(8:21), inv16 or t(15;17) translocations should be treated as any other de novo AML with similar cytogenetics. In summary, the major prognostic factor is related to the pathogenetic mechanisms of the leukaemia. Cytogenetics and molecular features are a better predictor of outcome than patient history. Patients should receive standard induction therapy. However, the long-term outcome is relatively poor; the best results being obtained among patients undergoing allogeneic transplantation.

An ins(X;11)(q24;q23) fuses the MLL and the Septin 6/KIAA0128 gene in an infant with AML-M2

The MLL (HRX, ALL-1 HTRX) gene at chromosome band 11q23 frequently is rearranged in acute lymphoblastic and myeloblastic leukemia. To date, more than 40 different 11q23 abnormalities have been described on the cytogenetic level, and at least 25 of the respective fusion partner genes are cloned. The vast majority of the respective reciprocal translocations generate a chimeric 5'-MLL/partner-3' gene on the derivative 11q23. In this work, we report a unique ins(X;11)(q24;q23) in an infant with acute myeloid leukemia (AML-M2) that fuses the human KIAA0128 gene at Xq24 with MLL. In contrast to the typical reciprocal MLL translocations, however, we provide evidence that the 5'-MLL/KIAA0128-3' fusion resides on Xq24 rather than on 11q23. The KIAA0128 gene encodes the human Septin 6 protein, which contains an ATP-GTP binding motif and three nuclear targeting sequences in its carboxy terminus. The maintenance of the reading frame of the 5'-MLL/KIAA0128-3' mRNA fusion allows for the formation of a novel chimeric protein. Septin 6 is the third member of the Septins that is fused to the MLL protein; the other two are hCDCrel at 22q11 and MSF at 17q25.

Molecular emergence of acute myeloid leukemia during treatment for acute lymphoblastic leukemia

Therapy-related acute myeloid leukemias (t-AML) with translocations of the MLL gene are associated with the use of topoisomerase II inhibitors. We established the emergence of the malignant clone in a child who developed t-AML with a t(11;19) (q23;p13.3) during treatment for acute lymphoblastic leukemia (ALL). The MLL-ENL and the reciprocal ENL-MLL genomic fusions and their chimeric transcripts were characterized from samples collected at the time of t-AML diagnosis. We used PCR with patient-specific genomic primers to establish the emergence of the MLL-ENL fusion in serially obtained DNA samples. The MLL-ENL fusion was not detectable in bone marrow at the time of ALL diagnosis or after 2 months of chemotherapy (frequency <8.3 x 10(-7) cells(-1)). The genomic fusion was first detected in bone marrow after 6 months of treatment at a frequency of one in 4,000 mononuclear bone marrow cells; the frequency was one in 70 cells after 20 months of therapy. At the first detection of MLL-ENL, the only topoisomerase II inhibitors the patient had received were one dose of daunorubicin and two doses of etoposide. The MLL-ENL fusion was not detectable in blood at the time of ALL diagnosis or after 0.7, 2, 8, 10, and 12 months of therapy but was detectable in blood at 16 months (one in 2.3 x 10(4) cells). Recombinogenic Alu sequences bracketed the breakpoints in both fusions. These data indicate that the malignant clone was not present before therapy, arose early during chemotherapy, and was able to proliferate even during exposure to antileukemic therapy.

Retroviral transduction model of mixed lineage leukemia fused to CREB binding protein

The in-frame fusion of mixed lineage leukemia to CREB binding protein has been cloned from several patients with t-acute myeloid leukemia and a t(11;16)(q23;p13). A murine retroviral transduction model of mixed lineage leukemia fused to CREB binding protein successfully recapitulates the disease. Interestingly, the mice also develop a preleukemic phase reminiscent of what is often seen in patients with t(11;16). From this work, it was determined that minimally, the amino terminus of mixed lineage leukemia fused to the bromodomain and histone acetyltransferase domain of CREB binding protein are necessary for developing acute myeloid leukemia. This model provides a useful tool for understanding the biologic basis of mixed lineage leukemia leukemogenesis and for developing and testing potential therapeutic agents.

Biology and outcome of childhood acute megakaryoblastic leukemia: a single institution's experience

To describe the clinical and biologic features of pediatric acute megakaryoblastic leukemia (AMKL) and to identify prognostic factors, experience at St Jude Children's Research Hospital was reviewed. Of 281 patients with acute myeloid leukemia treated over a 14-year period, 41 (14.6%) had a diagnosis of AMKL. Six patients had Down syndrome and AMKL, 6 had secondary AMKL, and 29 had de novo AMKL. The median age of the 22 boys and 19 girls was 23.9 months (range, 6.7-208.9 months). The rate of remission induction was 60.5%, with a 48% rate of subsequent relapse. Patients with Down syndrome had a significantly higher 2-year event-free survival (EFS) estimate (83%) than did other patients with de novo AMKL (14%) or with secondary AMKL (20%; P < or =.038). Among patients who had de novo AMKL without Down syndrome, 2-year EFS was significantly higher after allogeneic bone marrow transplantation (26%) than after chemotherapy alone (0%; P =.019) and significantly higher when performed during remission (46%) than when performed during persistent disease (0%; P =.019). The 5-year survival estimates were significantly lower for de novo AMKL (10%) than for other forms of de novo AML (42%; P <.001). Treatment outcome is very poor for patients with AMKL in the absence of Down syndrome. Remission induction is the most important prognostic factor. Allogeneic transplantation during remission offers the best chance of cure; in the absence of remission, transplantation offers no advantage over chemotherapy alone. (Blood. 2001;97:3727-3732)

Genetic predisposition and treatment-related leukemia

Treatment-related leukemias are one of the most devastating late complications of cancer therapy. Patients with rare cancer predisposition syndromes including neurofibromatosis type 1 and inherited p53 mutations are at an increased risk for this complication. Other patients may have increased susceptibility because they possess common genetic polymorphisms in drug-metabolizing enzymes that result in impaired detoxification of chemotherapy or inefficient repair of drug-induced genetic damage. We review studies that have identified a potential role for polymorphisms in the genes encoding the glutathione-S-transferases (GSTs), NAD(P) H: quinone oxidoreductase, myeloperoxidase, N-acetyltransferase (NATs), cytochrome P450 (CYP) 1A1 and 3A4, methylenetetrahydrofolate reductase (MTHFR), cystathionine-beta-synthase (CBS), and others in the etiology of primary or secondary acute leukemias, and therapy-related complications. The identification of high risk polymorphisms and use of pharmacogenetically-guided therapies holds promise to improve the outcome of cancer therapy and reduce the risk of treatment-related leukemias.

Leukemias related to treatment with DNA topoisomerase II inhibitors

The epipodophyllotoxins etoposide and teniposide and other DNA topoisomerase II inhibitors including anthracyclines and dactinomycin are highly efficacious anticancer drugs. All are associated with a distinct form of leukemia characterized by chromosomal translocations as a treatment complication. Most of the translocations disrupt a breakpoint cluster region (bcr) of the MLL gene at chromosome band 11q23. Other characteristic translocations also may occur. The normal function of the nuclear enzyme DNA topoisomerase II is to catalyze changes in DNA topology between relaxed and supercoiled states by transiently cleaving and re-ligating both strands of the double helix. Anticancer drugs that are DNA topoisomerase II inhibitors are cytotoxic because they form complexes with DNA and DNA topoisomerase II. The complexes decrease the re-ligation rate, disrupt the cleavage-re-ligation equilibrium, and have a net effect of increasing cleavage. The increased cleavage damages the DNA and leads to chromosomal breakage. Cells with irreparable DNA damage die by apoptosis. The association of DNA topoisomerase II inhibitors with leukemia suggests that the drug-induced, DNA topoisomerase II-mediated chromosomal breakage may be relevant to translocations in addition to this anti-neoplastic, cytotoxic action. Epidemiological studies, genomic translocation breakpoint cloning and in vitro DNA topoisomerase II cleavage assays together lead to a model for treatment-related leukemia in which DNA topoisomerase II causes chromosomal breakage and translocations form when the breakage is repaired.

Second malignant neoplasms in five-year survivors of childhood cancer: childhood cancer survivor study

BACKGROUND

Because survival rates among childhood cancer patients are increasing, assessing the risk of second and subsequent malignant neoplasms (SMNs) is ever more important. Using the Childhood Cancer Survivor Study cohort, we identified the risk of SMNS:

METHODS

A retrospective cohort of 13 581 children diagnosed with common cancers before age 21 years and surviving at least 5 years was constructed with the use of data from patients treated at 25 U.S. and Canadian institutions. SMNs were ascertained through self-administered questionnaires and verified by pathology reports. Information on therapeutic exposures was abstracted from medical records. The risk of SMN was evaluated by standardized incidence ratios (SIRs) and excess absolute risk. Poisson multiple regression models were used to assess the impact of host and therapy factors on the risk of developing SMNS: All statistical tests were two-sided.

RESULTS

In 298 individuals, 314 SMNs were identified (SIR = 6.38; 95% confidence interval [CI] = 5.69 to 7.13). The largest observed excess SMNs were bone and breast cancers (SIR = 19.14 [95% CI = 12.72 to 27.67] and SIR = 16.18 [95% CI = 12.35 to 20.83], respectively). A statistically significant excess of SMNs followed all childhood cancers. In multivariate regression models adjusted for therapeutic radiation exposure, SMNs of any type were independently associated with female sex (P<.001), childhood cancer at a younger age (P for trend <.001), childhood Hodgkin's disease or soft-tissue sarcoma (P<.001 and P =.01, respectively), and exposure to alkylating agents (P for trend =.02). Twenty years after the childhood cancer diagnosis, the cumulative estimated SMN incidence was 3.2%. However, only 1.88 excess malignancies occurred per 1000 years of patient follow-up.

CONCLUSIONS

Success in treating children with cancer should not be overshadowed by the incidence of SMNS: However, patients and health-care providers must be aware of risk factors for SMNs so that surveillance is focused and early prevention strategies are implemented.

Therapy related leukemias: susceptibility, prevention and treatment

Acute leukemia is the most frequent therapy-related malignancy. Together with the increasing use of chemo- and radiotherapy, individual predisposing factors play a key role. Most of secondary leukemias can be divided in two well-defined groups: those secondary to the use of alkylating agents and those associated to topoisomerase inhibitors. Leukemias induced by alkylating agents usually follow a long period of latency from the primary tumour and present as myelodysplasia with unbalanced chromosomal aberrations. These frequently include deletions of chromosome 13 and loss of the entire or of part of chomosomes 5 or 7. The loss of the coding regions for tumor suppressor genes from hematopoietic progenitor cells is a particularly unfavourable event, since the remaining allele becomes susceptible to inactivating mutations leading to the leukemic transformation. The tumorigenic action of topoisomerase inhibitors is on the other hand due to the formation of multiple DNA strand breaks, resolved by chromosomal translocations. Among these, chromosome 11, band q23, where the myeloid-lymphoid leukemia (MLL) gene is located, is often involved. Frequent partners are chromosomes 9, 19 and 4 in the t(9;11), t(19;11) and t(4;11) translocations. Younger age, a mean period of latency of 2 years and monocytic subtypes are characteristic features of this type of leukemia. Among patients at risk for secondary leukemia, those with Hodgkin's disease are the most extensively studied, with the major impact of alkylating agents included in the chemotherapy schedule. The same is true for non-Hodgkin's lymphoma, while in multiple myeloma and acute lymphoblastic leukemia determinants are the dose of melphalan and of epypodophyllotoxin, respectively. Patients with breast, ovarian and testicular neoplasms are also at risk, in particular if trated with the association of alkylating agents and topoisomerase II inhibitors. According to the EBMT registry, in patients with lymphoma treated with high-dose therapy and autologous stem cell transplantation the cumulative risk of inducing leukemia at 5 years is 2.6%. Among treatment options, supportive therapy is indicated in older patients, while allogeneic stem cell transplantation, related or matched-unrelated, is feasible in younger patients. These data indicate the need for the identification of predisposing factors for secondary leukemia. In particular, frequent follow-up of patients at high-risk should be performed and any peripheral blood cytopenia should be considered suspicious. Whenever possible, the exclusion of drugs known to be leukemogenic from the treatment schedules should be considered, especially in young patients.

Thioguanine substitution alters DNA cleavage mediated by topoisomerase II

Thiopurines and topoisomerase II-targeted drugs (e.g., etoposide) are widely used anticancer drugs. However, topoisomerase II-targeted drugs can cause acute myeloid leukemia, with the risk of this secondary leukemia linked to a genetic defect in thiopurine catabolism. Chronic thiopurines result in thioguanine substitution in DNA. The effect of these substitutions on DNA topoisomerase II activity is not known. Our goal was to determine whether deoxythioguanosine substitution alters DNA cleavage stabilized by human topoisomerase II. We studied four variations of a 40 mer oligonucleotide with a topoisomerase II cleavage site, each with a single deoxythioguanosine in a different position relative to the cleavage site (-1 or +2 in the top and +2 or +4 in the bottom strand). Deoxythioguanosine substitution caused position-dependent quantitative effects on cleavage. With the -1 or +2 top and +2 or +4 bottom substitutions, mean topoisomerase II-induced cleavage was 0.6-, 2.0-, 1.1-, and 3.3-fold that with the wild-type substrate (P=0. 011, < 0.008, 0.51, and < 0.001, respectively). In the presence of 100 microM etoposide, cleavage was enhanced for wild-type and all thioguanosine-modified substrates relative to no etoposide, with the +4 bottom substitution showing greater etoposide-induced cleavage than the wild-type substrate (P=0.015). We conclude that thioguanine incorporation alters the DNA cleavage induced by topoisomerase II in the presence and absence of etoposide, providing new insights to the mechanism of thiopurine effect and on the leukemogenesis of thiopurines, with or without topoisomerase inhibitors.

First-line chemotherapy with local treatment can prevent external-beam irradiation and enucleation in low-stage intraocular retinoblastoma

PURPOSE

To evaluate the efficacy of first-line chemotherapy (CT) in preventing external-beam radiotherapy (EBR) and/or enucleation in patients with retinoblastoma (Rbl).

PATIENTS AND METHODS

Twenty-four patients with newly diagnosed unilateral or bilateral Rbl received CT associated with local treatment (LT). Two to five courses of etoposide and carboplatin were administered at 3- to 4-week intervals, depending on tumor response, and were completed each time by LT.

RESULTS

Tumor response was observed in all eyes. Twenty-one of 24 patients showed a complete response (CR) that persisted at a median follow-up (FU) of 31 months (range, 4 to 41 months). Among the three patients who relapsed, two were lost to FU and one died of progressive disease. CR was achieved by CT and LT alone in 15 (71.4%) of 21 patients with less advanced disease (groups I to III). Six other patients with advanced disease (groups IV and V) experienced treatment failure and needed salvage treatment by EBR and/or enucleation. The difference between the two patient groups with regard to disease stage was statistically significant (P <.0001). EBR could be avoided in 13 (68.4%) of 19 patients, who presented with groups I to III (15 eyes) and group V (one eye) disease, whereas enucleation could be avoided in only two (40%) of five.

CONCLUSION

CT combined with intensive LT is effective in patients with groups I to III Rbl, permitting the avoidance of EBR in the majority of these young children and, thus, reducing the risk of long-term sequelae. This is in contrast with the disappointing results for patients with groups IV and V Rbl, in whom EBR and/or enucleation was needed.

Dyshaemopoiesis in adults: a practical classification for diagnosis and management

Dyshaemopoiesis is a heterogeneous disease that may be classified into non-clonal and clonal dyshaemopoiesis. Non-clonal dyshaemopoiesis comprises reversible disorders with DNA synthesis impairment in dividing cells of the bone marrow by avitaminosis through various mechanisms or direct DNA damage from multiple causes. Complete haematologic recovery is obtained after vitamin supplementation or suppression of a myelotoxic agent. On the contrary, clonal dyshaemopoiesis is a group of chronic and usually irreversible diseases that may culminate in acute leukaemia (AL). These so called myelodysplastic syndromes (MDS) and their variants may be classified as primary, secondary and other diseases with doubtful clonality. A detailed classification of dyshaemopoiesis in adults may offer partial help in the diagnosis and management of dyshaemopoiesis. Pathobiological studies in progress allow better understanding of MDS and consequently the establishment of new modalities of treatment.

Phase I study of paclitaxel, carboplatin, and increasing days of prolonged oral etoposide in ovarian, peritoneal, and tubal carcinoma: a gynecologic oncology group study

PURPOSE

Given the activity of prolonged oral etoposide in platinum and paclitaxel-resistant ovarian carcinoma, a phase I trial was conducted that combined increasing days of oral etoposide therapy with paclitaxel and carboplatin in chemotherapy-naive patients with ovarian peritoneal and tubal carcinoma to establish a maximum-tolerated dose (MTD) of this combination.

PATIENTS AND METHODS

Paclitaxel at 175 mg/m(2) given over 3 hours and carboplatin at an area under the curve of 5 were administered on day 1 followed by oral etoposide 50 mg/m(2)/d beginning on day 2. The number of days of etoposide therapy was escalated on the basis of toxicity. Toxicity end points included neutropenic sepsis, grade 4 thrombocytopenia, or grade 3 neutropenia or thrombocytopenia during etoposide administration. Cycles were repeated every 21 days for a maximum of six courses. Due to hematologic toxicity, the duration of the paclitaxel infusion was decreased to 1 hour for a second stage of accrual.

RESULTS

Of 52 patients studied, 29 were in the first stage of accrual. Dose-limiting toxicity occurred with 8 days of oral etoposide, making the MTD six days of therapy. Twenty-three patients were entered into the second stage of accrual. Dose-limiting toxicity occurred at 12 days of oral etoposide, making the MTD 10 days of therapy. Three patients developed acute myeloid leukemia 16, 27, and 35 months after receiving a cumulative dose of 200 mg/m(2), 1,200 mg/m(2), and 2,400 mg/m(2), respectively.

CONCLUSION

One-hour paclitaxel, carboplatin, and oral etoposide at 50 mg/m(2)/d for 10 days is tolerable without supportive therapy. The leukemogenic potential is cause for concern and precludes its use in chemotherapy-naive ovarian carcinoma.

The long-term complications of chemotherapy in childhood genitourinary tumors

Combination chemotherapy, often in conjunction with surgery and external radiotherapy, is utilized in most children with tumors of the genitourinary tract. These chemotherapeutic agents are capable of causing a variety of delayed toxicities. Common late complications include cardiotoxicity associated with prior exposure to an anthracycline, pulmonary dysfunction, infertility in males due to prior therapy with alkylating agents, and secondary leukemia in individuals treated with epipodophyllotoxins.

Localized childhood Hodgkin's disease: response-adapted chemotherapy with etoposide, bleomycin, vinblastine, and prednisone before low-dose radiation therapy-results of the French Society of Pediatric Oncology Study MDH90

PURPOSE

The French Society of Pediatric Oncology MDH82 study demonstrated the effectiveness of 20 Gy irradiation of involved fields after doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) or mechlorethamine, vincristine, procarbazine, and prednisone/ABVD chemotherapy in children with localized Hodgkin's disease (HD). The response to primary chemotherapy was the only predictor of survival. To reduce long-term treatment complications without compromising efficacy, the MDH90 study was based on a new chemotherapy regimen devoid of both alkylating agents and anthracycline, followed by 20 Gy of radiotherapy (RT) for good responders.

PATIENTS AND METHODS

From January 1990 to July 1996, 202 children were enrolled from 30 institutions. Good responders to four cycles of vinblastine, bleomycin, etoposide (VP16), and prednisone (VBVP) were given 20 Gy of RT and no further therapy. Poor responders were given vincristine, procarbazine, prednisone, and doxorubicin. After a second evaluation, good responders were given 20 Gy of RT, and poor responders were given 40 Gy of RT.

RESULTS

One hundred seventy-one patients (85%) were good responders to VBVP, 27 (15%) were poor responders, and four did not respond. With a median follow-up of 74 months (range, 25 to 117 months), the 5-year overall survival rate (mean +/- SD) is 97.5% +/- 2.1%, and the event-free survival rate (mean +/- SD) is 91.1% +/- 1.8%. Significant predictors of worse event-free survival in multivariate analysis were hemoglobin < 10.5 g/L, "b" biologic class, and nodular sclerosis.

CONCLUSION

These results suggest that most children with clinical stage I and II HD can be treated with chemotherapy devoid of alkylating agents and anthracycline, followed by low-dose RT.

Detection of leukemia-associated MLL-GAS7 translocation early during chemotherapy with DNA topoisomerase II inhibitors

Leukemias with MLL gene translocations are a complication of primary cancer treatment with DNA topoisomerase II inhibitors. How early translocations appear during primary cancer treatment has not been investigated. We tracked the leukemic clone with an MLL gene translocation during neuroblastoma therapy in a child who developed acute myeloid leukemia. The karyotype of the leukemic clone showed del(11)(q23). We used panhandle PCR-based methods to isolate the breakpoint junction involving MLL and an unknown partner gene. Marrow DNA from neuroblastoma diagnosis and DNA and RNA from serial preleukemic marrows were examined for the translocation. The karyotypic del(11)(q23) was a cryptic t(11;17). GAS7, a growth arrest-specific gene at chromosome band 17p13, was the partner gene of MLL. Two different MLL-GAS7 fusion transcripts were expressed. The translocation was already detectable by 1.5 months after the start of neuroblastoma treatment. The translocation was not detectable in the marrow at neuroblastoma diagnosis or in peripheral blood lymphocyte DNAs of six normal subjects. GAS7 is a new partner gene of MLL in treatment-related acute myeloid leukemia. MLL gene translocations can be present early during anticancer treatment at low cumulative doses of DNA topoisomerase II inhibitors. Although MLL has many partner genes and most have not been characterized, panhandle PCR strategies afford new means for detecting MLL gene translocations early during therapy when the partner gene is unknown.

Myelodysplasia

The epidemiology of myelodysplasia, or myelodysplastic syndrome (MDS), is in evolution. As populations are aging and therapies for cancer are improving, the frequency of this disease is increasing. Recent population surveys and case-control studies are reviewed. Knowledge of the molecular pathogenesis and pathophysiology of MDS is advancing at a remarkable pace and new information on molecular events is presented. The treatment of MDS is complex and highly individualized. Although many patients are older and may have significant co-morbid disease or poor performance status, there are curative options with allogeneic transplantation for selected patients. The recent transplant publications are reviewed. Other investigative treatment approaches, including the use of new chemotherapy agents, growth factor combinations, and antithymocyte globulin appear promising and are reviewed.

Etoposide in prostate cancer

Hormone refractory prostate cancer is a disease that kills approximately 39,000 people per year. No single chemotherapeutic agent or regimen has been demonstrated to provide a survival advantage in this disease. Etoposide as a single agent, both in i.v. and oral formulations has not proven to be effective. In the 1990s, however, etoposide has been combined with several agents to create novel treatment regiments for patients with hormone refractory disease. Several of these regimens, all involving oral etoposide, have demonstrated promising results in Phase II trials and early results suggest that they may increase survival for hormone refractory patients, although this remains to be tested in a Phase III trial setting.

Therapy-related malignancies following treatment of germ cell cancer

Given the young age at which testicular cancer is treated and the excellent prognosis for patients suffering from this disease, therapy-related malignancies represent a significant problem. Therapy-related solid tumors are associated mainly with the use of radiation therapy. The risk for developing a therapy-related solid tumor is approximately 2- to 3-fold increased compared with the general population. Therapy-related leukemias are associated predominantly with chemotherapy, particularly with the use of topoisomerase-II inhibitors and alkylating agents. In general, the cumulative incidence of therapy-related leukemia is low. It is approximately 0.5% and 2% at 5 years of median follow-up for patients receiving etoposide at cumulative doses < or = 2 g/m2 and > 2 g/m2, respectively. High cumulative doses of etoposide given over a short period of time appear to be less leukemogenic than a similar dose of etoposide given over a longer period of time. There might, additionally, be a synergistic effect of cisplatin and etoposide on the induction of therapy-related leukemia. For patients who receive high-dose chemotherapy with autologous stem-cell support, the risk of therapy-related myelodysplastic syndrome and leukemia appears to be substantially lower compared with that reported in non-Hodgkin's lymphoma patients undergoing high-dose chemotherapy. The transplantation procedure itself does not appear to add to the therapy-related leukemia risk. The risk-benefit analysis in patients with testicular cancer clearly favors the use of current treatment regimens including high-dose chemotherapy. However, even the acceptably low number of therapy-related leukemias should encourage the search for equally effective but less toxic therapies.

Late toxicity following curative treatment of testicular cancer

Cisplatin appears to be the major cause for long-term toxicity in patients treated for testicular cancer. Long-term side effects consist mainly of nephrotoxicity, ototoxicity, and neurotoxicity as well as gonadal damage. Following standard-dose chemotherapy approximately 20% to 30% of patients will be affected by long-term side effects, although not all these side effects will cause an impaired quality of life. Several strategies have been or currently are being evaluated to reduce acute and long-term complications including the introduction of equally effective, but less toxic regimens, or the use of cytoprotective agents such as amifostine. Secondary acute myeloid leukemia and secondary myelodysplastic syndrome probably represent the worst possible long-term complications of cancer therapy in those patients who originally were cured of their primary testicular cancer. Therapy-related solid tumors are mainly associated with the use of radiation therapy and the risk for developing a therapy-related solid tumor is increased approximately two to three times compared to the general population. In contrast, therapy-related leukemias are predominantly associated with chemotherapy, particularly with the use of topoisomerase-II inhibitors and alkylating agents. In general, the cumulative incidence of therapy-related leukemia following treatment of germ cell cancer is low. It is approximately 0.5% and 2% at 5 years of median follow-up for patients receiving etoposide at cumulative doses< or = 2 g/m(2) and >2 g/m(2), respectively. The risk-benefit analysis in patients with testicular cancer clearly favors the use of current treatment regimens including high-dose chemotherapy. However, even the acceptably low number of therapy-related long-term complications should encourage the search for equally effective but less toxic therapies. This review will highlight important available data about therapy-related toxicity and particularly, therapy-related malignancies following cisplatin-etoposide-based chemotherapy.

Acute myelogenous leukemia after treatment for malignant germ cell tumors in children

PURPOSE

To identify the long-term sequelae of therapy for malignant germ cell tumors (GCTs).

PATIENTS AND METHODS

Between 1980 and 1998, 1,132 patients were prospectively enrolled onto the German nontesticular GCT studies. A total of 442 patients received chemotherapy using combinations of the drugs cisplatin, ifosfamide, etoposide, vinblastine, and bleomycin, and 174 patients were treated with a combination of chemotherapy and radiotherapy. Median follow-up duration was 38 months (range, 6 to 199 months).

RESULTS

Six patients developed therapy-related acute myelogenous leukemia (t-AML). There was no t-AML among patients treated with surgery (n = 392) or radiotherapy only (n = 124). The Kaplan-Meier estimates of the cumulative incidence (at 10 years) of t-AML were 1.0% for patients treated with chemotherapy (three of 442) and 4.2% for patients treated with combined chemotherapy and radiotherapy (three of 174). Notably, four of these six patients had been treated according to a standard protocol with modest cumulative chemotherapy doses. Five patients had received less than 2 g/m(2) epipodophyllotoxins, and four patients had received less than 20 g/m(2) ifosfamide. Four patients presented with AML, two with myelodysplasia in transformation to AML. In five patients, cytogenetic aberrations were found, four of which were considered characteristic for t-AML. Four patients died despite antileukemic therapy. One patient is alive but suffered a relapse of his GCT, and one patient is alive and well. No secondary solid neoplasm was observed.

CONCLUSION

In patients with AML after treatment for GCT, several pathogenetic mechanisms must be considered. AML might evolve from a malignant transformation of GCT components without any influence of the chemotherapy. On the other hand, the use of alkylators and topoisomerase II inhibitors is associated with an increased risk of t-AML. Future studies will show if the reduction of treatment intensity in the current protocol reduces the risk of secondary leukemia in these patients.

Oral etoposide for refractory and relapsed neuroblastoma

PURPOSE

To describe the efficacy of oral etoposide against resistant stage 4 neuroblastoma.

PATIENTS AND METHODS

Patients with refractory or recurrent stage 4 neuroblastoma were treated with etoposide 50 mg/m(2) taken orally each day, in two or three divided doses, for 21 consecutive days. Treatment could be repeated after a 1-week period. Extent-of-disease studies included imaging with 131-iodine-metaiodobenzylguanidine and extensive bone marrow (BM) sampling.

RESULTS

Oral etoposide was used in 20 children between the ages of 2 and 11 years (median, 6 years). Prior treatment included high doses of alkylating agents and a median of 4.5 cycles of etoposide-containing chemotherapy, with cumulative etoposide doses of 1,800 mg/m(2) to 3,935 mg/m(2) (median, 2,300 mg/m(2)). Oral etoposide produced antineuroblastoma effects in four of four children with disease refractory to intensive induction treatment; sampling variability could account for resolution (n = 3) or reduction (n = 1) of BM involvement, but improvement in other markers also occurred. Antineuroblastoma effects were also evident in five of five children with asymptomatic relapses after a long chemotherapy-free interval: BM disease resolved and all other disease markers significantly improved in two patients, and disease markers improved or stabilized in three patients on treatment for more than 6 months. In these nine patients, extramedullary toxicity was absent, neutropenia did not occur, transfusional support was not needed, and preliminary data suggested little immunosuppression (phytohemagglutinin responses). Oral etoposide was ineffective in all (11 of 11) patients with rapidly growing tumor masses.

CONCLUSION

Given the absence of toxicity to major organs, the minimal myelosuppression or immunosuppression, and the antineoplastic activity in patients with low tumor burdens after high-dose chemotherapy, limited use of low-dose oral etoposide should be considered for inclusion in postinduction consolidative treatment programs aimed at eradicating minimal residual disease.