The minimum CD34 threshold depends on prior chemotherapy in autologous peripheral blood stem cell recipients.
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We analysed 57 patients with non-myeloid malignancies who received a non-purged autologous PBSCT. All had similar mobilisation and conditioning regimens. A high prior chemotherapy score and the number of chemotherapy lines used (P = 0.015 and P = 0.01, respectively) were adverse predictors of CD34 cell yields. Lower CD34 values (P = 0.002) were seen in patients treated with potent stem cell toxins (BCNU, melphalan, CCNU and mustine), designated toxicity factor 4 agents (TF4). All patients infused with grafts containing CD34 cell doses between 1.0 and 2.0 x 10(6)/kg (range 1.25-1.90) engrafted by day 51. The only variable associated with slow platelet recovery was exposure to TF4 (P = 0.007). The majority of patients with CD34 >1.0 x 10(6)/kg achieved rapid and sustained engraftment and the only predictive factor of delayed recovery is prior exposure to stem cell toxins. Potential PBSCT candidates should if possible avoid first line and salvage chemotherapy containing TF4 drugs. We therefore advocate a minimum CD34 threshold of >1.0 x 10(6)/kg in patients without extensive prior chemoradiotherapy, and > or = 2.0 x 10(6)/kg in all other patients. (+info)
L-Asparagine synthetase in serum as a marker for neoplasia.
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L-Asparagine synthetase appears in serum approximately 7 days after the s.c. implantation of 1 X 10(5) cells of Leukemia 5178Y/AR (resistant to L-asparaginase) and increases in activity as the neoplasm grows and metastasizes. The principal source of the enzyme is the primary tumor. After intravranial inoculation of tumor, the rate of leakage of the enzyme is more pronounced than when the subcutaneous, intramuscular, or intraperitoneal routes are used. 1-(2-Chloroethyl)-3-cyclohexyl-1-nitrosourea (NSC 79037), a nitro-sourea effective in the palliation of L5178Y/AR, temporarily halts the influx of enzyme into the blood stream, as does surgical excision of the s.c. tumor nodules. Treatment of mice with L-asparaginase within 24 hr of inoculation of the tumor markedly augments both tumor growth and the rate of penetration of L-asparagine synthetase into the circulation. Several other L-asparagine synthetase into the circulation. Several other L-asparaginase-resistant tumors also were found to spill L-asparagine synthetase into the serum, but the correlation between this phenomenon and the specific activity of the enzyme in homogenates of the tumor was imperfect. (+info)
High-dose BEAM chemotherapy with autologous haemopoietic stem cell transplantation for Hodgkin's disease is unlikely to be associated with a major increased risk of secondary MDS/AML.
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Hodgkin's disease is curable in the majority of patients, although a proportion of patients are resistant to or relapse after initial therapy. High-dose therapy with autologous stem cell support has become the standard salvage therapy for patients failing chemotherapy, but there have been reports of a high incidence of myelodysplasia/acute myeloid leukaemia (MDS/AML) following such treatment. Patients who receive such therapy form a selected group, however, who have already been subjected to other leukaemogenic factors, such as treatment with alkylating agents. In order to ascertain the true risk of MDS/AML, comparison must be made with other patients subjected to the same risks but not undergoing transplantation. We report a retrospective comparative study of 4576 patients with Hodgkin's disease from the BNLI and UCLH Hodgkin's databases, which includes 595 patients who have received a transplant. Statistical analysis including Cox's proportional hazards multivariate regression model with time-dependent covariates was employed. This analysis reveals that the risk of developing MDS/AML was dominated by three factors, namely quantity of prior therapy (relative risk [RR] 2.01, 95% confidence intervals [CI] 1.49-2.71, for each treatment block, P < 0.0001) and whether the patient had been exposed to MOPP (RR 3.61, 95% CI 1.64-7.95, P = 0.0009) or lomustine chemotherapy (RR 4.53, 95% CI 1.96-10.44, P = 0.001). Following adjustment for these factors in the multivariate model the relative risk associated with transplantation was 1.83 (95% CI 0.66-5.11, P = 0.25). This study provides no evidence of a significantly increased risk of MDS/AML associated with BEAM therapy and autologous transplantation in Hodgkin's disease. Concern over MDS/AML should not mitigate against the timely use of this treatment modality. (+info)
Procarbazine, lomustine, and vincristine (PCV) chemotherapy for anaplastic astrocytoma: A retrospective review of radiation therapy oncology group protocols comparing survival with carmustine or PCV adjuvant chemotherapy.
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PURPOSE: To determine any differences in outcome for patients with anaplastic astrocytoma (AA) treated with adjuvant carmustine (BCNU) versus procarbazine, lomustine, and vincristine (PCV) chemotherapy. MATERIALS AND METHODS: The Radiation Therapy Oncology Group (RTOG) database was reviewed for patients with newly diagnosed AA treated according to protocols that included either BCNU or PCV adjuvant chemotherapy. All patients were treated with radiation therapy. The outcome analysis included overall survival, taking into account patient age, extent of resection, Karnofsky performance status (KPS), and treatment group (BCNU v PCV). Stratified and nonstratified Cox proportional hazards models were used, as well as an analysis using matched cases between the groups. RESULTS: A total of 257 patients were treated with BCNU according to RTOG protocols 70-18, 83-02, and 90-06; 175 patients were treated with PCV according to RTOG protocol 94-04. All pretreatment characteristics except KPS were well balanced by treatment group; 61% of the BCNU group had a KPS of 90 to 100 compared with 73% of the PCV group (P =.0075). No statistically significant difference in survival was observed in any age group or by KPS or extent of surgery. The stratified analysis also showed no trends for improved survival by treatment group (P =. 40). The Cox model identified only age, KPS, and extent of surgery as important variables influencing survival, not treatment group. Matching cases between groups using age, KPS, and surgery resulted in 133 matched pairs. No difference in survival was observed (P =. 41). In a Cox model in which each matched pair is a strata, there was no difference between groups (P =.20). CONCLUSION: Using this retrospective analysis, there does not seem to be any survival benefit to PCV chemotherapy. Future phase III studies for patients with AA may need to consider whether BCNU or PCV is used in the control arm. (+info)
Treatment of children with medulloblastomas with reduced-dose craniospinal radiation therapy and adjuvant chemotherapy: A Children's Cancer Group Study.
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PURPOSE: Medulloblastoma is the most common malignant brain tumor of childhood. After treatment with surgery and radiation therapy, approximately 60% of children with medulloblastoma are alive and free of progressive disease 5 years after diagnosis, but many have significant neurocognitive sequelae. This study was undertaken to determine the feasibility and efficacy of treating children with nondisseminated medulloblastoma with reduced-dose craniospinal radiotherapy plus adjuvant chemotherapy. PATIENTS AND METHODS: Over a 3-year period, 65 children between 3 and 10 years of age with nondisseminated medulloblastoma were treated with postoperative, reduced-dose craniospinal radiation therapy (23.4 Gy) and 55.8 Gy of local radiation therapy. Adjuvant vincristine chemotherapy was administered during radiotherapy, and lomustine, vincristine, and cisplatin chemotherapy was administered during and after radiation. RESULTS: Progression-free survival was 86% +/- 4% at 3 years and 79% +/- 7% at 5 years. Sites of relapse for the 14 patients who developed progressive disease included the local tumor site alone in two patients, local tumor site and disseminated disease in nine, and nonprimary sites in three. Brainstem involvement did not adversely affect outcome. Therapy was relatively well tolerated; however, the dose of cisplatin had to be modified in more than 50% of patients before the completion of treatment. One child died of pneumonitis and sepsis during treatment. CONCLUSION: These overall survival rates compare favorably to those obtained in studies using full-dose radiation therapy alone or radiation therapy plus chemotherapy. The results suggest that reduced-dose craniospinal radiation therapy and adjuvant chemotherapy during and after radiation is a feasible approach for children with nondisseminated medulloblastoma. (+info)
Mismatch repair, G(2)/M cell cycle arrest and lethality after DNA damage.
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The role of the mismatch repair pathway in DNA replication is well defined but its involvement in processing DNA damage induced by chemical or physical agents is less clear. DNA repair and cell cycle control are tightly linked and it has been suggested that mismatch repair is necessary to activate the G(2)/M checkpoint in the presence of certain types of DNA damage. We investigated the proposed role for mismatch repair (MMR) in activation of the G(2)/M checkpoint following exposure to DNA-damaging agents. We compared the response of MMR-proficient HeLa and Raji cells with isogenic variants defective in either the hMutLalpha or hMutSalpha complex. Different agents were used: the cross-linker N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea (CCNU), gamma-radiation and the monofunctional methylating agent N-methyl-N-nitrosourea (MNU). MMR-defective cells are relatively sensitive to CCNU, while no differences in survival between repair-proficient and -deficient cells were observed after exposure to gamma-radiation. Analysis of cell cycle distribution indicates that G(2) arrest is induced at least as efficiently in MMR-defective cells after exposure to either CCNU or ionizing radiation. As expected, MNU does not induce G(2) accumulation in MMR-defective cells, which are known to be highly tolerant to killing by methylating agents, indicating that MNU-induced cell cycle alterations are strictly dependent on the cytotoxic processing of methylation damage by MMR. Conversely, activation of the G(2)/M checkpoint after DNA damage induced by CCNU and gamma-radiation does not depend on functional MMR. In addition, the absence of a simple correlation between the extent of G(2) arrest and cell killing by these agents suggests that G(2) arrest reflects the processing by MMR of both lethal and non-lethal DNA damage. (+info)
Relapses of childhood anaplastic large-cell lymphoma: treatment results in a series of 41 children--a report from the French Society of Pediatric Oncology.
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PURPOSE: To study response to chemotherapy and the outcome of children treated for a relapsed anaplastic large-cell lymphoma (ALCL) and to evaluate the role of bone marrow transplantation (BMT) in these patients. PATIENTS AND METHODS: Clinical data concerning the 41 relapses that occurred in 119 patients with ALCL enrolled in 3 consecutive studies since 1975 were analysed. First-line treatment consisted of intensive chemotherapy according to the COPAD protocol for the first series of 12 patients treated between 1975 and 1989 and to the SFOP (French Society of Pediatric Oncology) HM protocols for the 30 patients treated between 1989 and 1997. Twenty-eight patients were treated with CV(B)A (CCNU, vinblastine, ara-C with or without bleomycin), and the others with miscellaneous protocols for recurrent disease. Fifteen patients underwent autologous BMT and 1 allogeneic BMT while in CR2. RESULTS: Thirty-six of forty-one (88%) patients achieved CR2. With a median follow-up of 5 years, 12 patients died, 9 of their disease and 29 patients are alive in CR2 (20 patients), CR3 (5 patients), CR4 (2 patients), CR5 (1 patient) or CR6 (1 patient). Overall and disease-free survival are respectively 69% (53%-82%) and 44% (29%-61%) at three years. In univariate analysis, patients treated with ABMT while in CR2 did not appear to have a better outcome than the other. Remarkably, a long-lasting remission was obtained in 8 of 13 patients treated with weekly vinblastine for a relapse including 6 relapses occurring after ABMT. CONCLUSIONS: Relapsed ALCL are highly chemosensitive but over 40% of the patients experience several relapses. Prolonged conventional chemotherapy based on vinblastine might, in some cases, be as efficient as short intensive treatment with ABMT. (+info)
Mismatch repair and p53 independently affect sensitivity to N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea.
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The contributions of defective mismatch repair (MMR) and the p53-response to cell killing by N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea (CCNU) were evaluated. MMR defects were previously shown to be associated with CCNU sensitivity (G. Aquilina et al., Cancer Res., 58: 135-141, 1998). Unexpectedly, eight MMR-deficient variants of the A2780 human ovarian carcinoma cell line were 3-fold more resistant to CCNU than the MMR-proficient parental cells. The variants were members of a preexisting subpopulation of drug-resistant A2780 cells. In addition to deficient expression of the MMR protein hMLH1, an essential component of the hMutL alpha repair complex, the variants exhibited alterations in the expression of other genes that influence drug sensitivity. Although A2780 cells possess a wild-type p53 gene, all of the clones contained a heterozygous G to T tranversion at codon 172. This change resulted in a Val to Phe substitution and was associated with a constitutive production of high levels of p53, which was inactive as a transcriptional activator of bax and p21. The hMLH1/p53 defective variants displayed a less prominent cell cycle arrest and reduced apoptosis after CCNU treatment. In contrast, MMR-defective A2780 variants, which had a similar hMutL alpha defect but retained a wild-type p53, did exhibit the expected CCNU sensitivity. Expression of a dominant-negative p53val135 increased CCNU resistance of both MMR-proficient and MMR-deficient A2780 cells. Thus, defective MMR and p53 influence CCNU sensitivity in opposite directions. Their effects are independent, and sensitization by defective MMR does not require a functional p53 response. (+info)