No abstract

Purpose/Objectives Re-irradiation (re-RT) is the only potentially curative treatment option for patients with locally recurrent head and neck cancer (HNC). Given the significant morbidity with head and neck re-irradiation, interest in proton beam radiotherapy (PBRT) has increased. Herein, we report the first multi-institutional clinical experience using curative intent PBRT for re-RT in recurrent HNC. Materials/Methods A retrospective analysis of ongoing prospective data registries from 2-hybrid community practice and academic proton centers was conducted. Patients with recurrent HNC who had at least one prior course of definitive intent external beam RT were included. Acute and late toxicities were assessed by the National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 and by the Radiation Therapy Oncology Group late radiation morbidity scoring system, respectively. The cumulative incidence of locoregional failure was calculated with death as a competing risk. The actuarial twelve-month freedom from distant metastasis (FFDM) and overall survival (OS) rates were calculated with the Kaplan-Meier method. Results Ninety-two consecutive patients were treated with curative intent re-RT with PBRT between 2011 and 2014. Median follow-up among surviving patients was 13.3 months and among all patients was 10.4 months (interquartile range, 5.3-17.5 months). The median time between last RT and PBRT was 34.4 months. There were 76 patients with one prior RT course and 16 with two or more courses. Median PBRT dose was 60.6 Gy (RBE). Eighty-five percent of patients had prior HNC RT for an oropharynx primary and 39% had salvage surgery prior to re-RT. The cumulative incidence of locoregional failure at 12-months, with death as a competing risk, was 25.1%. Actuarial 12-month FFDM and OS were 84.0% and 65.2%, respectively. Acute grade ≥3 toxicities included mucositis (9.9%), dysphagia (9.1%), esophagitis (9.1%), and dermatitis (3.3%). There was one death during PBRT secondary to disease progression. Grade 3 or greater late skin and dysphagia toxicity were noted in 6 (8.7%) and 4 (7.1%) of patients, respectively. Two patients had grade 5 toxicity secondary to treatment-related bleeding. Conclusions Proton beam re-irradiation of the head and neck can provide effective tumor control with acceptable acute and late toxicity profiles likely secondary to the decreased dose to the surrounding normal, albeit previously irradiated tissue, though longer follow up is needed to confirm these findings.

No abstract

The properties of high frequency capillary waves generated by steep gravity waves on deep water have been measured with a high resolution laser optical slope gauge. The results have been compared with the steady theory of Longuet-Higgins (1963). Good qualitative agreement is obtained. However, the quantitative predictions of the capillary wave slopes cannot be verified by the data because the theory requires knowledge of an idealized quantity - the crest curvature of the gravity wave in the absence of surface tension - which cannot be measured experimentally.

The survival of patients with acute lymphoblastic leukemia (ALL) has improved significantly with the use of intensive multimodality treatment regimens including chemotherapy, high‐dose chemotherapy and stem cell rescue, and radiation therapy when indicated. This report summarizes the treatment strategies, especially radiation therapy in the Children's Oncology Group for children with ALL. Currently, radiation therapy is only indicated for children with high‐risk CNS involvement at diagnosis or relapse, testicular relapse and as part of the conditioning regimen for hematopoietic stem cell transplantation. Future research strategies regarding the indications for and dosages of radiation therapy and novel radiation techniques are discussed.