ABSTRACT
PURPOSE: Radiation-induced angiosarcoma (RAS) of the chest wall/breast has a poor prognosis due to the high percentage of local failures. The efficacy and side effects of re-irradiation plus hyperthermia (reRT + HT) treatment alone or in combination with surgery were assessed in RAS patients. PATIENTS AND METHODS: RAS was diagnosed in 23 breast cancer patients and 1 patient with melanoma. These patients had previously undergone breast conserving therapy (BCT, n = 18), mastectomy with irradiation (n=5) or axillary lymph node dissection with irradiation (n = 1). Treatment consisted of surgery followed by reRT + HT (n = 8), reRT + HT followed by surgery (n = 3) or reRT + HT alone (n = 13). Patients received a mean radiation dose of 35 Gy (32-54 Gy) and 3-6 hyperthermia treatments (mean 4). Hyperthermia was given once or twice a week following radiotherapy (RT). RESULTS: The median latency interval between previous radiation and diagnosis of RAS was 106 months (range 45-212 months). Following reRT + HT, the complete response (CR) rate was 56 %. In the subgroup of patients receiving surgery, the 3-month, 1- and 3-year actuarial local control (LC) rates were 91, 46 and 46 %, respectively. In the subgroup of patients without surgery, the rates were 54, 32 and 22 %, respectively. Late grade 4 RT toxicity was seen in 2 patients. CONCLUSION: The present study shows that reRT + HT treatment--either alone or combined with surgery--improves LC rates in patients with RAS.
Subject(s)
Hemangiosarcoma/etiology , Hemangiosarcoma/therapy , Hyperthermia, Induced/methods , Neoplasms, Radiation-Induced/therapy , Radiotherapy, Conformal/methods , Thoracic Neoplasms/therapy , Thoracic Surgical Procedures/methods , Aged , Aged, 80 and over , Combined Modality Therapy , Female , Humans , Male , Middle Aged , Neoplasms, Radiation-Induced/etiology , Radiotherapy, Conformal/adverse effects , Thoracic Neoplasms/etiology , Thoracic Wall/radiation effects , Thoracic Wall/surgery , Treatment OutcomeABSTRACT
In meta-analysis of clinical trials, often meta-regression analyses are performed to explain the heterogeneity in treatment effects that usually exist between trials. A popular explanatory variable is the risk observed in the control group, the baseline risk. The relationship between the treatment effect and the baseline risk is investigated by fitting a linear model that allows randomness on the true baseline risk by assuming a normal distribution with unknown mean and variance. However, the normality assumption could be too strong to adequately describe the underlying distribution. Therefore, we developed a new semi-parametric method that relaxes the normality assumption to a more flexible and general distribution. We applied a penalized Gaussian mixture distribution to represent the baseline risk distribution. Furthermore, a bivariate hierarchical model is formulated in order to take into account the correlation between the baseline and treatment effect. To fit the proposed model, a penalized likelihood function is maximized by an Expectation Maximization (EM) algorithm. We illustrate our method on a number of simulated data sets and on a published meta-analysis data set.
Subject(s)
Meta-Analysis as Topic , Risk , Statistical Distributions , Treatment Outcome , Anticholesteremic Agents/therapeutic use , Clinical Trials as Topic/statistics & numerical data , Coronary Disease/drug therapy , Coronary Disease/mortality , Effect Modifier, Epidemiologic , Humans , Likelihood Functions , Linear Models , Longitudinal Studies , Reference Values , Statistics, Nonparametric , Stochastic Processes , Survival AnalysisABSTRACT
As part of an epidemiological study on the oral health of Flemish schoolchildren, fluoride use was studied together with risk factors (medical history, tap water fluoride concentration, use of fluoride supplements, toothpaste and brushing habits). Fluorosis was scored according to the Thylstrup-Fejerskov index (TFI) in children aged 11 years (4,128 children examined). Explanatory variables were recorded yearly, starting at the age of 7. Earliest toothpaste use was reported at the age of 1. By age 7, 99.7% of the children reported the use of toothpaste (90% fluoride-containing), but only 13.9% reported using a pea-sized amount. At age 7, 66% of the children had received systemic fluoride supplements during at least part of their childhood. At 11 years, 92% of the children used a fluoride-containing toothpaste and 6% still received systemic fluoride supplements. Fluorosis was present in about 10% of all the children examined, mainly TFI score 1 (7.3% in upper central incisors). Logistic regression established tooth brushing frequency and fluoride supplement use, in addition to tap water fluoride concentrations above 0.7 mg/l, as significant risk factors when the presence of fluorosis on at least one tooth was used as outcome variable. Children having fluorosis had a lower risk of caries, both in the primary (median dmft 1, range 0-10 vs. 2, range 0-12) and permanent dentition (median DMFT 0, range 0-5 vs. 0, range 0-11).
