Biomedical subjects

Robert K Danish

Publications and source records attributed to Robert K Danish.

7 recordsLinked to original sources

PubMed2006

Changes in bone mineral density in survivors of childhood acute lymphoblastic leukemia.

BACKGROUND: There is little information about factors modulating bone mineral density (BMD) in survivors of childhood acute lymphoblastic leukemia (ALL). PROCEDURE: We analyzed data from 57 survivors (26 male, 52 Caucasian) who underwent two serial quantitative computed tomography (QCT) studies of BMD. Using multiple linear regression, we evaluated the association of BMD change with demographic variables, treatment history, hormone therapy, exercise, and tobacco and alcohol use. RESULTS: The median age was 3.4 years (range, 0.9-17.4 years) at diagnosis of ALL; the median age at the first QCT (Study I) was 15.0 years (range, 10.6-31.0 years) and at the second QCT (Study II) was 18.2 years (range, 14.2-35.3 years). Mean height increased 4.7 cm and mean weight increased 8.8 kg between Studies I and II. While the mean BMD increased 9.33 mg/cc (P = 0.003), the BMD Z-score increased only slightly (0.21 SD, P = 0.035). Cortical bone density increased significantly (approximately 25.3 mg/cc; P = 0.001), but the ratio of trabecular to cortical BMD decreased significantly (P = 0.045). Factors independently associated with unfavorable BMD changes included older age at diagnosis (P = 0.001), female sex (P = 0.018), and nutritional supplementation (0.032). Alcohol (P = 0.009) was an unfavorable factor in a univariable analysis. CONCLUSIONS: Bone mineral accretion during adolescence is attenuated in childhood ALL survivors by a comparative deficit in trabecular versus cortical bone deposition. BMD is influenced favorably by exercise in early adolescence and unfavorably by the use of nutritional supplements and alcohol. These results provide new information about behavioral factors that affect bone accrual in survivors of childhood ALL and warrant definitive evaluation in a larger cohort.

Adolescent↗

PubMed2005

ACTH deficiency in childhood cancer survivors.

BACKGROUND: Adrenocorticotropin deficiency (ACTHD) can be clinically subtle, but life-threatening if not recognized. We assessed the prevalence of ACTHD in survivors of childhood cancer according to tumor diagnosis/therapy. PROCEDURE: Chart review of endocrine/oncology history was performed in 310 childhood cancer survivors. Patients were referred to endocrine clinic because of slow growth, fatigue, or abnormal pubertal timing. Evaluation of growth hormone (GH), thyrotropin (TSH), ACTH, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) was performed. Low response to metyrapone and/or low dose ACTH test defined ACTHD. RESULTS: ACTHD was identified in 56 (18%), [44 of 182 (24%) central nervous system (CNS) tumors, 3 of 18 (17%) non-CNS cranial tumors, 9 of 97 (9%) hematologic malignancies]. Of the 56 with ACTHD, 53 (95%) had received cranial irradiation (mean 45.5 Gy, range 14-70 Gy); three had not: one each with craniopharyngioma, hypothalamic astrocytoma, and brain stem glioma. All but one also had GH deficiency and/or central hypothyroidism. CONCLUSIONS: Childhood cancer survivors with greatest risk for ACTHD had craniopharyngioma, other suprasellar tumor, or medulloblastoma or > or =24 Gy cranial irradiation. We recommend annual testing for ACTHD for 10-15 years and continued lifelong surveillance after CNS tumor or cranial irradiation, in patients with other hypothalamic-pituitary deficiencies or symptoms of ACTHD.

Adrenocorticotropic Hormone↗

PubMed2004

Hypothalamic dysfunction after chemotherapy.

Cranial irradiation with or without chemotherapy can cause hypothalamic-pituitary dysfunction. Chemotherapy without cranial irradiation has not been thought to cause such deficiency. In order to determine whether chemotherapy without cranial irradiation can lead to hormonal deficiency, we reviewed the medical records of 362 childhood cancer patients who underwent full hypothalamic-pituitary evaluation because of altered growth and development after oncological therapy (1987-2002). Of these, 31 received chemotherapy but no cranial or total body irradiation and had no CNS tumor: 18 had hematological malignancy and 13 had a solid tumor of the torso or extremity. Duration of follow-up was 13.0 +/- 4.1 years (mean +/- SD). Growth hormone deficiency (GHD) was identified in 15 (48%), central hypothyroidism (TSH-D) in 16 (52%), and pubertal abnormalities in 10 (32%). Pubertal abnormalities included precocious puberty in two (6%), gonadal failure in five of 27 who were old enough to assess puberty (19%), and gonadotropin deficiency in three of 27 (11%). GHD and TSH-D were co-existent in eight patients (26%). Overall, 81% (n = 25) had GHD, TSH-D, precocious puberty, and/or gonadotropin deficiency. None had ACTH or ADH deficiency or primary hypothyroidism. Of note, this was not a study of prevalence, but rather an evaluation of clinically referred patients. In conclusion, hypothalamic dysfunction may occur in survivors of non-CNS tumors who receive chemotherapy but do not receive cranial irradiation. We recommend at least annual observation of growth rate and pubertal development of all children treated for pediatric malignancies, with evaluation for GHD, TSH-D, pubertal abnormalities, and other hypothalamic dysfunction in all poorly-growing cancer survivors, even those not treated with cranial irradiation.

Adolescent↗

PubMed2003

Risk factors for the development of obesity in children surviving brain tumors.

Hypothalamic obesity, a syndrome of intractable weight gain due to hypothalamic damage, is an uncommon but devastating complication for children surviving brain tumors. We undertook a retrospective evaluation of the body mass index (BMI) curves for the St. Jude Children's Research Hospital brain tumor population diagnosed between 1965 and 1995 after completion of therapy to determine risk factors for the development of obesity. Inclusion criteria were: diagnosis less than 14 yr of age, no spinal cord involvement, ambulatory, no supraphysiologic hydrocortisone therapy (>12 mg/m(2) x d), treatment and follow-up at St. Jude Children's Research Hospital, and disease-free survival greater than 5 yr (n = 148). Risk factors examined were age at diagnosis, tumor location, histology, extent of surgery, hydrocephalus requiring ventriculoperitoneal shunting, initial high-dose glucocorticoids, cranial radiation therapy, radiation dosimetry to the hypothalamus, intrathecal chemotherapy, and presence of endocrinopathy. Analyses were performed both between groups within a risk factor and against BMI changes for age in normal children older than 5.5 yr (the age of adiposity rebound). Risk factors were: age at diagnosis (P = 0.04), radiation dosimetry to the hypothalamus (51-72 Gy, P = 0.002 even after hypothalamic and thalamic tumor exclusion), and presence of any endocrinopathy (P = 0.03). In addition, risk factors when compared with BMI slope for the general American pediatric population included: tumor location (hypothalamic, P = 0.001), tumor histology (craniopharyngioma, P = 0.009; pilocytic astrocytoma, P = 0.043; medulloblastoma, P = 0.039); and extent of surgery (biopsy, P = 0.03; subtotal resection, P = 0.018). These results verify hypothalamic damage, either due to tumor, surgery, or radiation, as the primary cause of obesity in survivors of childhood brain tumors. In particular, hypothalamic radiation doses of more than 51 Gy are permissive. These results reiterate the importance of the hypothalamus in energy balance, provide risk assessment criteria for preventative measures before the development of obesity in at-risk patients, and suggest therapeutic strategies to reduce the future development of obesity.

Astrocytoma↗

PubMed2002

Preirradiation endocrinopathies in pediatric brain tumor patients determined by dynamic tests of endocrine function.

PURPOSE: To prospectively evaluate pediatric patients with localized primary brain tumors for evidence of endocrinopathy before radiotherapy (RT). METHODS AND MATERIALS: Seventy-five pediatric patients were evaluated with the arginine tolerance test and L-dopa test for growth hormone secretory capacity and activity; thyroid-stimulating hormone surge and thyrotropin-releasing hormone stimulation test for the hypothalamic-thyroid axis; the 1-microg adrenocorticotropin hormone (ACTH) and metyrapone test for ACTH reserve; and, depending on age, a gonadotropin-releasing hormone stimulation test to determine gonadotropin response. The study included 38 male and 37 female patients, age 1-21 years with ependymoma (n = 35), World Health Organization (WHO) Grade I-II astrocytoma (n = 18), WHO Grade III-IV astrocytoma (n = 10), craniopharyngioma (n = 7), optic pathway tumor (n = 4), and germinoma (n = 1). Seven patients receiving dexamethasone at the time of the evaluation were excluded from the final analysis. RESULTS: Of 68 assessable patient, 45 (66%) had evidence of endocrinopathy before RT, including 15 of 32 patients (47%) with posterior fossa tumors. Of the 45 patients, 38% had growth hormone deficiency, 43% had thyroid-stimulating hormone secretion abnormality, 22% had an abnormality in ACTH reserve, and 13% had an abnormality in age-dependent gonadotropin secretion. CONCLUSION: The incidence of pre-RT endocrinopathy in pediatric brain tumor patients is high, including patients with tumors not adjacent to the hypothalamic-pituitary unit. These data suggest an overestimation in the incidence of radiation-induced endocrinopathy. Baseline endocrine function should be determined for brain tumor patients before therapy. The potential for radiation-induced endocrinopathy alone cannot be used as an argument for alternatives to RT for most patients. Pre-RT endocrinopathy may be an early indicator of central nervous system damage that will influence the functional outcome unrelated to RT.

Adolescent↗

PubMed2002

Outcomes of growth hormone replacement therapy in survivors of childhood acute lymphoblastic leukemia.

PURPOSE: Little is known about the long-term efficacy or adverse effects of growth hormone (GH) replacement therapy in survivors of childhood acute lymphoblastic leukemia (ALL) who have GH deficiency. We investigated the adult height of patients who had received GH and estimated their risk of leukemia relapse or development of a second malignancy. PATIENTS AND METHODS: Of 910 patients treated for ALL at a single institution, 47 had received GH replacement therapy. The linear growth of these 47 patients was retrospectively evaluated. Their risk of leukemia relapse or second malignancy was compared with that of survivors who did not undergo GH therapy. RESULTS: The median height SD score at the start of GH therapy had decreased by 1.0 since the time of diagnosis of ALL. After a median duration of 4.5 years of GH therapy, adult height SD scores improved and approached height SD scores at the time of diagnosis of ALL. The median adult height for male patients was 173.2 cm (range, 157 to 191.9 cm), and for female patients, it was 158.1 cm (range, 141 to 168 cm). None of the patients developed adverse effects requiring discontinuation of GH treatment. At the 7-year and 11-year landmarks in continuous hematologic remission, there was no statistical evidence that GH therapy was associated with leukemia relapse or development of a second malignancy. CONCLUSION: This study suggests that GH replacement therapy is safe and efficacious for the correction of GH deficiency in survivors of childhood ALL.

Adolescent↗

PubMed2002

Radiation dose-volume effects on growth hormone secretion.

PURPOSE: Growth hormone (GH) deficiency is a known consequence of central nervous system irradiation. The relationship between the dose to the hypothalamus and the time to onset of clinically significant GH deficiency is unknown. Conformal radiotherapy (CRT) techniques allow for a more accurate determination of hypothalamic dosimetry. We correlated the dosimetry of the hypothalamus and the peak GH value after CRT in children with localized primary brain tumors. METHODS AND MATERIALS: The arginine tolerance/L-dopa test was performed before (baseline) and repeated 6 and 12 months after CRT in 25 children (median age 4.8 years) with ependymoma (n = 15) or low-grade (n = 8) or high-grade (n = 2) astrocytoma. None had evidence of GH deficiency (arginine tolerance/L-dopa peak GH level >10 ng/mL [10 microg/L]) at baseline. Peak GH levels were modeled as a function of time after CRT and volume of the hypothalamus receiving a dose within the specified intervals of 0-20 Gy, 20-40 Gy, and 40-60 Gy. The model was used to predict the change in the peak GH levels over time (0-12 months) and fit under the assumption that the integral effect of irradiation was a linear sum of the products of the volume receiving a particular dose and the impact of that dose. RESULTS: The peak GH level declined during the 0-12 months after CRT (p < 0.0001). GH deficiency was observed in 11 children at 6 months and a total of 20 children at 12 months. As expected, the effect of the dose interval 0-20 Gy was smaller than the 20-40-Gy dose interval; the largest effect was noted with the dose interval 40-60 Gy. The peak GH level may be predicted using the following estimating equation within the time limit of 0-12 months: GH(t)=Exp[ln(bGH)-(0.00058V(0-20 Gy)+0.00106V(20-40 Gy)+0.00156V(40-60 Gy))x t], where bGH is the baseline peak GH level, V(0-20 Gy), V(20-40 Gy), and V(40-60 Gy) is the percent-volume of the hypothalamus irradiated from 0 to 20 Gy, 20 to 40 Gy, and 40 to 60 Gy, respectively, and t is time after irradiation. When included in the model, the rate of decline in the peak GH response also was influenced by hydrocephalus and tumor location. CONCLUSION: The peak GH response within 12 months after CRT depends on hypothalamic dose-volume effects and may be predicted on the basis of a linear model that sums the effects of the entire distribution of dose. The modeled effects may be used to optimize radiotherapy and minimize and treat GH deficiency.

Adolescent↗