Assessing the robustness of passive scattering proton therapy with regard to local recurrence in stage III non-small cell lung cancer: a secondary analysis of a phase II trial

Predictive model of the first failure pattern in patients receiving definitive chemoradiotherapy for inoperable locally advanced non-small cell lung cancer (LA-NSCLC)

Purpose

To analyze patterns of failure in patients with LA-NSCLC who received definitive chemoradiotherapy (CRT) and to build a nomogram for predicting the failure patterns in this population of patients.

Materials and methods

Clinicopathological data of patients with LA-NSCLC who received definitive chemoradiotherapy and follow-up between 2013 and 2016 in our hospital were collected. The endpoint was the first failure after definitive chemoradiotherapy. With using elastic net regression and 5-fold nested cross-validation, the optimal model with better generalization ability was selected. Based on the selected model and corresponding features, a nomogram prediction model was built. This model was also validated by ROC curves, calibration curve and decision curve analysis (DCA).

Results

With a median follow-up of 28 months, 100 patients experienced failure. There were 46 and 54 patients who experience local failure and distant failure, respectively. Predictive model including 9 factors (smoking, pathology, location, EGFR mutation, age, tumor diameter, clinical N stage, consolidation chemotherapy and radiation dose) was finally built with the best performance. The average area under the ROC curve (AUC) with 5-fold nested cross-validation was 0.719, which was better than any factors alone. The calibration curve revealed a satisfactory consistency between the predicted distant failure rates and the actual observations. DCA showed most of the threshold probabilities in this model were with good net benefits.

Conclusion

Clinicopathological factors could collaboratively predict failure patterns in patients with LA-NSCLC who are receiving definitive chemoradiotherapy. A nomogram was built and validated based on these factors, showing a potential predictive value in clinical practice.

Proton therapy for adults with mediastinal lymphomas: the International Lymphoma Radiation Oncology Group guidelines

Among adult lymphoma survivors, radiation treatment techniques that increase the excess radiation dose to organs at risk (OARs) put patients at risk for increased side effects, especially late toxicities. Minimizing radiation to OARs in adults patients with Hodgkin and non-Hodgkin lymphomas involving the mediastinum is the deciding factor for the choice of treatment modality. Proton therapy may help to reduce the radiation dose to the OARs and reduce toxicities, especially the risks for cardiac morbidity and second cancers. Because proton therapy may have some disadvantages, identifying the patients and the circumstances that may benefit the most from proton therapy is important. We present modern guidelines to identify adult lymphoma patients who may derive the greatest benefit from proton therapy, along with an analysis of the advantages and disadvantages of proton treatment.

Clinical implementations of 4D pencil beam scanned particle therapy: Report on the 4D treatment planning workshop 2016 and 2017

In 2016 and 2017, the 8th and 9th 4D treatment planning workshop took place in Groningen (the Netherlands) and Vienna (Austria), respectively. This annual workshop brings together international experts to discuss research, advances in clinical implementation as well as problems and challenges in 4D treatment planning, mainly in spot scanned proton therapy. In the last two years several aspects like treatment planning, beam delivery, Monte Carlo simulations, motion modeling and monitoring, QA phantoms as well as 4D imaging were thoroughly discussed. This report provides an overview of discussed topics, recent findings and literature review from the last two years. Its main focus is to highlight translation of 4D research into clinical practice and to discuss remaining challenges and pitfalls that still need to be addressed and to be overcome.

Proton Therapy for Head and Neck Cancers

Because of its sharp lateral penumbra and steep distal fall-off, proton therapy offers dosimetric advantages over photon therapy. In head and neck cancer, proton therapy has been used for decades in the treatment of skull-base tumors. In recent years the use of proton therapy has been extended to numerous other disease sites, including nasopharynx, oropharynx, nasal cavity and paranasal sinuses, periorbital tumors, skin, and salivary gland, or to reirradiation. The aim of this review is to present the physical properties and dosimetric benefit of proton therapy over advanced photon therapy; to summarize the clinical benefit described for each disease site; and to discuss issues of patient selection and cost-effectiveness.

Particle therapy of moving targets-the strategies for tumour motion monitoring and moving targets irradiation

Particle therapy of moving targets is still a great challenge. The motion of organs situated in the thorax and abdomen strongly affects the precision of proton and carbon ion radiotherapy. The motion is responsible for not only the dislocation of the tumour but also the alterations in the internal density along the beam path, which influence the range of particle beams. Furthermore, in case of pencil beam scanning, there is an interference between the target movement and dynamic beam delivery. This review presents the strategies for tumour motion monitoring and moving target irradiation in the context of hadron therapy. Methods enabling the direct determination of tumour position (fluoroscopic imaging of implanted radio-opaque fiducial markers, electromagnetic detection of inserted transponders and ultrasonic tumour localization systems) are presented. Attention is also drawn to the techniques which use external surrogate motion for an indirect estimation of target displacement during irradiation. The role of respiratory-correlated CT [four-dimensional CT (4DCT)] in the determination of motion pattern prior to the particle treatment is also considered. An essential part of the article is the review of the main approaches to moving target irradiation in hadron therapy: gating, rescanning (repainting), gated rescanning and tumour tracking. The advantages, drawbacks and development trends of these methods are discussed. The new accelerators, called "cyclinacs", are presented, because their application to particle therapy will allow making a breakthrough in the 4D spot scanning treatment of moving organs.

Prognostic value of pretherapy platelet elevation in oropharyngeal cancer patients treated with chemoradiation

The purpose of this study is to evaluate potential associations between increased platelets and oncologic outcomes in oropharyngeal cancer patients receiving concurrent chemoradiation. A total of 433 oropharyngeal cancer patients (OPC) treated with intensity-modulated radiation therapy (IMRT) with concurrent chemotherapy between 2002 and 2012 were included under an approved IRB protocol. Complete blood count (CBC) data were extracted. Platelet and hemoglobin from the last phlebotomy (PLTpre-chemoRT, Hgbpre-chemoRT ) before start of treatment were identified. Patients were risk-stratified using Dahlstrom-Sturgis criteria and were tested for association with survival and disease-control outcomes. Locoregional control (LRC), freedom from distant metastasis (FDM) and overall survival (OS) were decreased (p < 0.03, p < 0.04 and p < 0.0001, respectively) for patients with PLTpre-chemoRT value of ≥350 × 10(9) /L. Actuarial 5-year locoregional control (LRC) and FDM were 83 and 85% for non-thrombocythemic patients while patient with high platelets had 5-year LRC and FDM of 73 and 74%, respectively. Likewise, 5-year OS was better for patients with normal platelet counts by comparison (76 vs. 57%; p < 0.0001). Comparison of univariate parametric models demonstrated that PLTpre-chemoRT was better among tested models. Multivariate assessment demonstrated improved performance of models which included pretherapy platelet indices. On Bayesian information criteria analysis, the optimal prognostic model was then used to develop nomograms predicting 3-, 5- and 10-year OS. In conclusion, pretreatment platelet elevation is a promising predictor of prognosis, and further work should be done to elucidate the utility of antiplatelets in modifying risk in OPC patients.