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Biomedical subjects

Christopher D Mitchell

Publications and source records attributed to Christopher D Mitchell.

6 recordsLinked to original sources
PubMed2006

Prognosis of children with acute lymphoblastic leukemia (ALL) and intrachromosomal amplification of chromosome 21 (iAMP21).

Patients with acute lymphoblastic leukemia (ALL) and an intrachromosomal amplification of chromosome 21 (iAMP21) comprise a novel and distinct biological subgroup. We prospectively screened 1630 (84%) patients treated on the UK MRC ALL97 protocol for iAMP21 and herein present demographic, clinical, and survival data on the 28 (2%) children found to harbor this abnormality. They had a common or pre-B ALL immunophenotype, were significantly older (median 9 years vs 5 years), and had a lower white cell count (median 3.9 vs 12.4) compared with children without this abnormality. Notably, patients with iAMP21 had a significantly inferior event-free and overall survival at 5 years compared with other patients: 29% (95% confidence interval [CI], 13%-48%) versus 78% (95% CI, 76%-80%) and 71% (95% CI, 51%-84%) versus 87% (95% CI, 85%-88%), respectively. As a result of this 3-fold increase in relapse risk, newly diagnosed patients with iAMP21 recruited to the current UK MRC ALL2003 trial are being treated on the high-risk arm and are considered for bone marrow transplantation in first remission.

Child↗
PubMed2006

Principles for supporting task substitution in Australian general practice.

The workforce crisis in Australian general practice provides an impetus to consider new roles for other health professionals. Any innovations need to be appraised in advance for their potential risks and benefits. We propose six principles for this appraisal. These are the need for the new roles to: support the relationship between patients and their general practitioners; be clearly defined, aligned with competency and with relevant professional registration; be supported by practice systems providing safeguards against medical error; be underpinned by a system ensuring informed patient consent to activities being undertaken by members of the general practice team; be supported by effective medical indemnity insurance and be supported with appropriate financing.

Attitude of Health Personnel↗
PubMed2004

Three distinct subgroups of hypodiploidy in acute lymphoblastic leukaemia.

This study of children and adults with acute lymphoblastic leukaemia (ALL) is the largest series of patients with hypodiploidy (<46 chromosomes) yet reported. The incidence of 5% was independent of age. Patients were subdivided by the number of chromosomes; near-haploidy (23-29 chromosomes), low hypodiploidy (33-39 chromosomes) and high hypodiploidy (42-45 chromosomes). The near-haploid and low hypodiploid groups were characterized by their chromosomal gains and a doubled hyperdiploid population. Structural abnormalities were more frequent in the low hypodiploid group. Near-haploidy was restricted to children of median age 7 years (range 2-15) whereas low hypodiploidy occurred in an older group of median age 15 years (range 9-54). Patients with 42-45 chromosomes were characterized by complex karyotypes involving chromosomes 7, 9 and 12. The features shared by the few patients with 42-44 chromosomes and the large number with 45 justified their inclusion in the same group. Survival analysis showed a poor outcome for the near-haploid and low hypodiploid groups compared to those with 42-45 chromosomes. Thus cytogenetics, or at least a clear definition of the modal chromosome number, is essential at diagnosis in order to stratify patients with hypodiploidy into the appropriate risk group for treatment.

Adolescent↗
PubMed2003

Outcome heterogeneity in childhood high-hyperdiploid acute lymphoblastic leukemia.

High hyperdiploidy (HeH) (51 to 65 chromosomes) is found in one third of children with acute lymphoblastic leukemia and is associated with a good prognosis. Cytogenetic features may further refine this prognosis and identify patients with a poor outcome. We examined the effect of sex, age, individual trisomies, modal number, and structural abnormalities on survival among 700 children with HeH. Univariate analysis showed that age. sex, +4, +10, +18, and a high modal number were associated with survival. Multivariate analysis however, revealed that only age, sex, +4, and +18 were independent indicators. Hazard scores for predicting relapse and mortality were constructed. Three risk groups with 5-year event-free survival (EFS) rates of 86%, 75%, and 50% (P <.0001) were identified. The high-risk group comprised boys older than 9 years, boys aged 1 through 9 years without +18, and girls older than 9 years without +18, while girls aged 1 through 9 years with +18 had the best EFS. In terms of mortality, those younger than age 10 years with both +4 and +18 had an improved survival (96% vs 84% at 5 years, P <.0001). These findings confirm that the outcome of children with HeH is heterogeneous and that specific trisomies can identify patients with the greatest and least risk of treatment failure.

Adolescent↗
PubMed2003

Use of sarcoma-based chemotherapy in a case of congenital mesoblastic nephroma with liver metastases.

Congenital mesoblastic nephroma was originally considered to be a benign neoplasm. A more aggressive cellular form, however, that has a close relationship to congenital fibrosarcoma, is widely described. Previous reported sites of metastases are the lungs, heart, brain, and bone. We describe a patient with isolated metastasis to liver and review the management, together with evidence that it may be more appropriate to use a vincristine, ifosfamide, doxorubicin, and etoposide (VIDE) regimen rather than Wilm's tumor-based regimens in those cases for which chemotherapy is indicated.

Antineoplastic Combined Chemotherapy Protocols↗