Robert C. Trueworthy

A reliable method for evaluating drug compliance in children with cancer

Poor drug compliance may cause a decreased survival of children with malignancies. Children who fail to take their medications are not receiving optimum amounts of chemotherapy and suboptimal therapy causes a shortened survival in children with cancer. This is a study of prednisone compliance in 52 children with cancer during three distinct phases of therapy. The patients were either known to be taking prednisone (on‐therapy group), off prednisone (off‐therapy group), or their compliance was unknown (unknown group). Evaluation of prednisone compliance was attempted by measuring hemoglobin level changes, weight changes, and random urinary 17‐ketogenic steroids. The results obtained show that while hemoglobin and weight changes are not helpful, a random urine 17‐ketogenic steroid assay is able to differentiate clearly those patients who are taking their prednisone. By the use of this assay it was found that 33% of patients who by protocol and instruction were supposed to be receiving prednisone were not complying. Separate analysis of adolescents revealed an even more alarming 59% noncompliance rate. This striking level of noncompliance strongly suggests that the survival of patients may be threatened by noncompliance.

Pediatric oncology group experience with modified LSA2-L2 therapy in 107 children with non-Hodgkin's lymphoma (Burkitt's lymphoma excluded)

From September 1976 to August 1979 the Pediatric Oncology Group accessed 145 children to study the effectiveness of modified LSA2‐L2 therapy for the treatment of non‐Hodgkins lymphoma (NHL). Burkitts lymphoma patients were ineligible; E‐rosette‐positive patients with ≥ 25% blasts in the marrow entered after February 1977 were reported separately. Radiotherapy could be used to treat patients with compressive mediastinal disease at diagnosis and was prescribed for those with residual abdominal disease as demonstrated by second‐look surgery on completion of induction chemotherapy. Confirmation of diagnosis by the Pathology Panel and Repository Center for Lymphoma Clinical Trials was mandatory. Diagnostic tissues of 131 patients were reviewed. Among 107 evaluable patients, 91 (85%) achieved complete remission. Differences in response rates among the three major histologic groups (lymphoblastic, undifferentiated, and large cell) were of statistical significance, with response being poorest for diffuse undifferentiated lymphoma (P = 0.03). Failure‐free survival did not differ significantly for the three major histologic diagnoses. While response rate was lowest for Murphy Stage III patients (79%), the differences among the stages were not significant. Stage was not a significant prognostic factor for failure‐free survival (P = 0.08). The number of patients still at risk and the Kaplan‐Meier estimate of percentage of patients remaining at risk after 3 years is: Stage I, 8 (100%); Stage II, 10 (67%); Stage III, 28 (57%); Stage IV, 6 (39%); and > 25% blasts, 1 (13%). Stage III failure curves for lymphoblastic disease show continuing stepwise failure through 3 years. Among patients with diffuse large cell and undifferentiated disease, most failures occurred by 8 months. M1 and M2 levels of marrow involvement were not prognostic among children with lymphoblastic disease. The presence of a mediastinal mass was a significant factor contributing to failure in children with lymphoblastic disease without marrow involvement. Leucocytosis > 10,000/1, was a significant (P = <0.001) factor predicting failure‐free survival for patients with large cell lymphoma. The delivery of radiotherapy was not a significant factor in achieving remission. No consistent benefit resulted from using radiotherapy to treat postinduction residual disease demonstrated on second‐look exploration. The LSA2‐L2 regimen was associated with considerable toxicity, severe or worse in 77% and life‐threatening to 40% of these patients. Four died of toxicity. However, therapy was given more easily and safely as investigator experience increased. Maintenance therapy was delivered on an out patient basis without complications in most instances. This study demonstrates the ability of the LSA2‐L2 regimen to produce long‐term remissions, or to “cure” 60% to 70% of children among the major histologic categories of childhood NHL, excepting Burkitts lymphoma. Long‐term survival, or “cure”, occurs in 90% with Stages I and II disease and some 50% of those with Stages III and IV disease. Neither radiotherapy nor second‐look surgical procedures appear to influence outcome. The continuous relapse pattern seen in lymphoblastic disease involving the mediastinum suggests the need for more intensive repetitive therapy “up‐front”. The relapse pattern of non‐lymphoblastic disease suggests the discontinuation of therapy after 1 year.

Metastasizing Chordoma in Early Childhood

A 2 1/2-year-old female with a sphenooccipital-vertebral chordoma presented with neck pain, torticollis, fever, a lytic lesion of C2 vertebra, and bilateral nodular infiltrates in the lung. The lung biopsy revealed multiple tumor emboli by an enigmatic epithelioid-appearing neoplasm with immunohistochemical staining for vimentin, cytokeratin, and epithelial membrane antigen. A thorough roentgenographic evaluation disclosed a destructive, prepontine mass in the region of the clivus, erosion of the odontoid process, and compression of the cervical spinal cord. The patient died after a clinical course of 3 months. We identified 16 additional cases of metastasizing chordomas in the pediatric-age population; this case is the first to our knowledge with pathologically documented pulmonary metastasis at presentation.

Monitoring of inosine monophosphate dehydrogenase activity in mononuclear cells of children with acute lymphoblastic leukemia: enzymological and clinical aspects.

Inosine 5′‐monophosphate dehydrogenase (IMPDH; EC1.1.1.205) catalyzes the rate‐limiting step in guanine nucleotide biosynthesis, and may play an important role in treatment of patients with antipurines.

Management of children with isolated testicular leukemia

Since 1975, nine children with testicular leukemia were treated at the University of Kansas Medical Center on a standard protocol. Six patients presented with overt testicular leukemia and three patients had microscopic testicular leukemia detected on a biopsy done after 3 years of continuous complete remission. All patients had an M1 bone marrow at the time of testicular relapse and one patient had a concomitant central nervous system (CNS) relapse. Therapy consisted of testicular irradiation, CNS chemoprophylaxis, and systemic reinduction chemotherapy. Systemic maintenance therapy after the testicular relapse consisted of 6‐mercaptopurine and methotrexate with vincristine/prednisone pulses adminsitered in the same basic dose and schedule as the patienťs original maintenance regimen. These nine patients had a mean duration of first remission of 33 months and a mean duration of second remission of 45+ months. Four patients have relapsed (two bone marrow, one CNS, one CNS + bone marrow), but five patients remain in their second complete remission for 33+ to 94+ months from the time of testicular relapse. These results demonstrate that, in some children, testicular leukemia represents a site of temporary drug resistance and long‐term second remissions can be obtained (once local disease is controlled) by using the initial maintenance chemotherapy regimen.

Reversal of 6-mercaptopurine and 6-methylmercaptopurine ribonucleoside cytotoxicity by amidoimidazole carboxamide ribonucleoside in Molt F4 human malignant T-lymphoblasts

Cytotoxicity of 6-mercaptopurine (6MP) and 6-methylmercaptopurine ribonucleoside (Me-MPR) was studied in Molt F4 human malignant lymphoblasts. Both drugs are converted into methylthioIMP (Me-tIMP), which inhibits purine de novo synthesis. Addition of amidoimidazole carboxamide ribonucleoside (AICAR) circumvented inhibition of purine de novo synthesis, and thus partly prevented 6MP and Me-MPR cytotoxicity. Purine nucleotides, and especially adenine nucleotides, were recovered by addition of AICAR. Under these conditions, Me-tIMP formation decreased. The results of this study indicate that formation of Me-tIMP may be important for 6MP cytotoxicity in Molt F4 cells. These data suggest that depletion of adenine nucleotides is the main cause for Me-tIMP cytotoxicity.

Vindesine and prednisone for remission induction in children with acute lymphocytic leukemia

Vinca alkaloids are effective anticancer agents. Vindesine is a recent vinca alkaloid derivative with antitumor effects shown in in vitro systems and in patients with acute lymphocytic leukemia (ALL). The present study was designed to investigate the therapeutic effectiveness and toxicity of vindesine in combination with prednisone for remission induction in late stage ALL in children. Sixteen children with late‐stage ALL were treated with vindesine 4.0 mg/m2/week intravenously and prednisone 60 mg/m2/day orally in four divided doses for minimum of three weeks. Thirteen children were evaluable. Of these patients, four had complete remission and four had partial response. Toxicity was well tolerated and consisted of bone pain, paresthesias, loss of deep tendon reflexes, leukopenia, and thrombocytopenia primarily. Abnormal liver function tests and fever were also noted in some patients. All patients had received vincristine and prednisone prior to vindesine prednisone combination. All patients had been resistant to vincristine prednisone combination prior to vindesine prednisone treatment. This study suggests effectiveness of vindesine in late stage ALL and lack of cross‐resistance of vindesine and vincristine.

Combination therapy in childhood leukaemia: in vitro studies of thiopurines and inhibitors of purine metabolism on apoptosis

Background: Methotrexate (MTX) followed by 6-mercaptopurine (6MP) is one of the best known combinations for the treatment of childhood acute lymphoblastic leukaemia. Tiazofurin (TF) and 6-thioguanine (TG) are also used as chemotherapy agents in the treatment of malignancies. We have examined the induction of apoptosis by combinations of these drugs to gain more insights into their efficacy in the treatment of malignancies. Methods: The induction of apoptosis was examined in Molt-4, a human malignant acute lymphoblastic T-cell line. The cells were exposed to increasing drug concentrations at various exposure times. Annexin V/FITC and propidium iodide (PI) were used as markers for apoptosis and cell death. Annexin V/FITC positive and PI positive cells were detected by flow-cytometric analysis. Results: Sequential 24-h exposure with MTX (0·005-0·02 µmol) followed by 6MP (1-10 µmol) and 24-h exposure with TF (5·20 µmol) followed by TG (0·5-2 µmol) showed a more than additive induction of apoptosis compared with single-drug exposure. Simultaneous administration of the drugs does not show an additive effect on apoptosis. Conclusions: The results of this study indicate that sequential administration of MTX before 6MP and of TF before TG may be essential for therapeutic success in the treatment of leukaemia.

Utilization of a human tumor cloning system to monitor for bone marrow involvement in children with non‐Hodgkin's lymphoma

The objective of this study was to evaluate the sensitivity of two methods for determining bone marrow involvement with non‐Hodgkins lymphoma. These methods were histologic review of bone marrow aspirates, and clot sections versus in vitro growth of lymphoma colonies on soft agar. Forty‐two bone marrow aspirates were studied from 14 children who were without bone marrow involvement at diagnosis. There were seven bone marrow aspirates (from five patients) that had histologic evidence of metastatic lymphoma. Six of these seven specimens formed colonies in vitro. Twenty‐nine of 35 histologically negative specimens showed no lymphoma colony growth. However, six histologically negative specimens (from three patients) formed lymphoma colonies. Both the Fishers exact test and the k statistic were significant, indicating not only an association between histology and in vitro culture results, but also a close agreement. In addition, growth of lymphoma colonies in vitro was associated statistically with both a short duration of complete remission and a short duration of survival.

In vitro sensitivity of normal granulocytic and lymphoma colonies to vinca alkaloids

Recently, a colony‐forming assay was developed in our laboratory for pediatric malignant lymphoid diseases. This assay supports the growth of lymphoma colonies (ML‐CFC) as well as normal granulocytic colonies (CFU‐C) and thus a direct comparison between the antineoplastic and myelosuppressive effects of a drug can be determined. To test specificity of this in vitro assay to structurally similar drugs, the inhibitory effects of three vinca alkaloids (vincristine, vindesine, vinblastine) on ML‐CFC (B‐, T‐, pre‐T‐cell types) and CFU‐C was determined. Our results demonstrate that all three vinca alkaloids were active agents in vitro and that a direct dose response effect occurred once a threshold dose was reached. Each vinca alkaloid had a different pattern of inhibitory effect on ML‐CFC and CFU‐C suggesting an inherent difference in drug metabolism by these cells. Also, based on the dose inhibiting 50% of colony formation, vinblastine was 94 times more inhibitory against malignant B‐cell ML‐CFCs than against granulocytic CFU‐C.