Date of Award

5-2006

Document Type

Thesis

Degree Name

Master of Dental Science (MDS)

Program

Orthodontics

Research Advisor

Edward Harris, Ph.D.

Committee

William Parris, D.D.S., M.S. Quinton C Robinson, D.D.S., M.S.

Abstract

Acute Lymphoblastic Leukemia (ALL) is the most common malignancy of childhood, constituting 31 percent of all childhood malignancies. Treatment strategies to target ALL include chemotherapeutic agents, irradiation of the neck and/or spine, and bone marrow transplantation. The aggressive nature of antineoplastic therapies often produces numerous craniofacial and dental sequelae as well as additional harmful effects to the entire body. Cranial irradiation may adversely affect the hypothalamic-pituitary axis decreasing growth hormone production. Consequently, children with ALL may experience a transient or permanent reduction in growth iatrogenically. Hand-wrist radiographs are valuable for evaluating maturational status in children with ALL. These radiographs allow for the comparison of a child’s chronological age with relative “bone age.” OBJECTIVE: This study used hand-wrist radiographs to determine the maturational status of children treated with ALL. Bone age was compared to the child’s chronological age to determine the delayed, normal, or advanced tempo of growth. The null hypothesis was that anti-neoplastic therapies have no discernible effect on a child’s tempo of bone maturation. METHODS: Handwrist radiographs (n=108 films) of 73 children (39 boys, 34 girls) treated at St. Jude Children’s Research Hospital for ALL were evaluated to assess “bone age.” Mean chronological age at diagnosis was 4.54 years (sd = 2.81). The number of films per child was highly skewed, since most were taken soon after the diagnosis of ALL (and, thus, close to the onset of treatment). Bone ages were scored for each of the 73 patients based on Greulich and Pyle’s 1959 standards (GP2), specifically the atlas method. RESULTS: We supposed that the combination of antimitotic drugs used to treat ALL would discernibly depress the childrens’ tempos of growth, so that BA-CA (bone age-chronological age) would become negative (and become larger during the course of treatment). We found no evidence of this in our study. In fact, since there was no depression of the rate of maturation during treatment, there was no need for a compensatory, or “catch-up,” phase. There was, then, no evidence that treatment for ALL had any effect on the progress of hand-wrist bone age towards maturity. There also was no detectable effect on the tempo of growth for those treated with cranial irradiation versus children with chemotherapy alone. In conclusion, treatment for ALL spares the tempo of growth as measured by HW bone age. This is a favorable outcome since treatment did not alter the duration of growth, so prognosis of normal adult status is good. This finding accounts for several prior studies that reported normal adult body dimensions (in the absence of radiation treatment) in subjects treated for ALL in childhood.

DOI

10.21007/etd.cghs.2006.0203

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