Evaluation of permanent alopecia in pediatric medulloblastoma patients treated with proton radiation

Background: To precisely calculate skin dose and thus to evaluate the relationship between the skin dose and permanent alopecia for pediatric medulloblastoma patients treated with proton beams. Methods: The dosimetry and alopecia outcomes of 12 children with medulloblastoma (ages 4-15 years) comprise the study cohort. Permanent alopecia was assessed and graded after completion of the entire therapy. Skin threshold doses of permanent alopecia were calculated based on the skin dose from the craniospinal irradiation (CSI) plan using the concept of generalized equivalent uniform dose (gEUD) and accounting for chemotherapy intensity. Monte Carlo simulations were employed to accurately assess uncertainties due to beam range prediction and secondary particles. Results: Increasing the dose of the CSI field or the dose given by the boost field to the posterior fossa increased total skin dose delivered in that region. It was found that permanent alopecia could be correlated with CSI dose with a threshold of about 21 Gy (relative biological effectiveness, RBE) with high dose chemotherapy and 30 Gy (RBE) with conventional chemotherapy. Conclusions: Our results based on 12 patients provide a relationship between the skin dose and permanent alopecia for pediatric medulloblastoma patients treated with protons. The alopecia risk as assessed with gEUD could be predicted based on the treatment plan information

Clinical Investigation: Late Effect Incidence of Second Malignancies Among Patients Treated With Proton Versus Photon Radiation Radiation Oncology

Summary This study represents the first comparative analysis of second cancer incidence rates for cohorts treated with proton or photon radiation. We compared the incidence of second cancers in 558 patients treated with proton radiation with a matched Surveillance, Epidemiology, and End Results cohort of 558 photontreated patients. After we adjusted for sex, age at treatment, primary site, and year of diagnosis, proton therapy was not associated with an increased risk of second malignancy (adjusted hazard ratio, 0.52; PZ.009). Purpose: Proton radiation, when compared with photon radiation, allows delivery of increased radiation dose to the tumor while decreasing dose to adjacent critical structures. Given the recent expansion of proton facilities in the United States, the long-term sequelae of proton therapy should be carefully assessed. The objective of this study was to compare the incidence of second cancers in patients treated with proton radiation with a population-based cohort of matched patients treated with photon radiation. Methods and Materials: We performed a retrospective cohort study of 558 patients treated with proton radiation from 1973 to 2001 at the Harvard Cyclotron in Cambridge, MA and 558 matched patients treated with photon therapy in the Surveillance, Epidemiology, and End Results (SEER) Program cancer registry. Patients were matched by age at radiation treatment, sex, year of treatment, cancer histology, and site. The main outcome measure was the incidence of second malignancies after radiation. Results: We matched 558 proton patients with 558 photon patients from the Surveillance, Epidemiology, and End Results registry. The median duration of follow-up was 6.7 years (interquartile range, 7.4) and 6.0 years (interquartile range, 9.3) in the proton and photon cohorts, respectively. The median age at treatment was 59 years in each cohort. Second malignancies occurred in 29 proton patients (5.2%) and 42 photon patients (7.5%). After we adjusted for sex, age at treatment, primary site, and year of diagnosis, proton therapy was not associated with an increased risk of second malignancy (adjusted hazard ratio, 0.52 [95% confidence interval, 0.32-0.85]; PZ.009). Conclusions: The use of proton radiation therapy was not associated with a significantly increased risk of secondary malignancies compared with photon therapy. Longer follow-up of these patients is needed to determine if there is a significant decrease in second malignancies. Given the limitations of the study, these results should be viewed as hypothesis generating.

A compilation of moored current meter and wind recorder data : volume XXXV, Long-Term Upper Ocean Study (LOTUS) ; (Moorings 764, 765, 766, 767, 770), May 1982 - April 1983

LOTUS was a two-year experiment near 34°N, 70°W, designed to acquire and analyse a continuous set of measurements of currents and temperatures in the upper, open ocean together with local hydrography, meteorology, and mesoscale oceanographic features. The first scientific moorings were deployed in May 1982. The first year of mooring data, from May 1982- April 1983, is presented here.Funding was provided by the Office of Naval Research under Contracts No. N00014-76-C-0197, NR 083-400 and N00014-84-C-0134, NR 083-400

Oxford Textbook of Neuro-Oncology

Part of the Oxford Textbooks in Clinical Neurology series, the Oxford Textbook of Neuro-Oncology covers the pathophysiology, diagnosis, classification, and management of tumours of the nervous system. The book provides a comprehensive overview of tumour subtypes, in accordance with WHO classifications, along with management plans for adult and paediatric populations. The international team of co-editors ensures that expert commentaries on existing and wide-reaching diagnostic and treatment guidelines (including NCCN and ESMO) are accessible by a global audience

Secondary Malignancy Risk Following Proton Radiation Therapy

Radiation-induced secondary malignancies are a significant, yet uncommon cause of morbidity and mortality among cancer survivors. Secondary malignancy risk is dependent upon multiple factors including patient age, the biological and genetic predisposition of the individual, the volume and location of tissue irradiated, and the dose of radiation received. Proton therapy (PRT) is an advanced particle therapy with unique dosimetric properties resulting in reduced entrance dose and minimal to no exit dose when compared with standard photon radiation therapy. Multiple dosimetric studies in varying cancer subtypes have demonstrated that PRT enables the delivery of adequate target volume coverage with reduced integral dose delivered to surrounding tissues, and modeling studies taking into account dosimetry and radiation cell biology have estimated a significantly reduced risk of radiation-induced secondary malignancy with PRT. Clinical data are emerging supporting the lower incidence of secondary malignancies after PRT compared with historical photon data, though longer follow-up in proton treated cohorts is awaited. This article reviews the current dosimetric and clinical literature evaluating the incidence of and risk factors associated with radiation-induced secondary malignancy following PRT

Cardiovascular disease in long-term survivors of pediatric Hodgkin's disease

Treatment of pediatric Hodgkin's disease is largely a success story enabling investigators to explore the late of effects of cancer treatment in long-term survivors. Since mediastinal irradiation is an important component in the management of pediatric Hodgkin's disease, there are potentially significant long-term effects on the cardiovascular system. These are frequently associated with radiation therapy, both with and without chemotherapy. This review article explores the effect of such therapy on the pericardium, myocardium, coronary arteries, branch pulmonary arteries, conduction system as well as the valves. Although early and late effects are identified, their significance remains somewhat unclear. The most severe changes are most often associated with outdated treatment techniques