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Concept: Proton therapy


Gold nanoparticles have attracted significant interest in cancer diagnosis and treatment. Herein, we evaluated the theranostic potential of dithiolated diethylenetriamine pentaacetic acid (DTDTPA) conjugated AuNPs (Au@DTDTPA) for CT-contrast enhancement and radiosensitization in prostate cancer.

Concepts: Cancer, Metastasis, Nanoparticle, Proton therapy, Prostate cancer, Radiation therapy, Gold, Hormonal therapy


Purpose This randomized trial compared outcomes of passive scattering proton therapy (PSPT) versus intensity-modulated (photon) radiotherapy (IMRT), both with concurrent chemotherapy, for inoperable non-small-cell lung cancer (NSCLC). We hypothesized that PSPT exposes less lung tissue to radiation than IMRT and thereby reduces toxicity without compromising tumor control. The primary end points were grade ≥ 3 radiation pneumonitis (RP) and local failure (LF). Patients and Methods Eligible patients had stage IIB to IIIB NSCLC (or stage IV NSCLC with a single brain metastasis or recurrent lung or mediastinal disease after surgery) who were candidates for concurrent chemoradiation therapy. Pairs of treatment plans for IMRT and PSPT were created for each patient. Patients were eligible for random assignment only if both plans satisfied the same prespecified dose-volume constraints for at-risk organs at the same tumor dose. Results Compared with IMRT (n = 92), PSPT (n = 57) exposed less lung tissue to doses of 5 to 10 Gy(RBE), which is the absorbed Gy dose multiplied by the relative biologic effectiveness (RBE) factor for protons; exposed more lung tissue was exposed to $ 20 Gy(RBE), but exposed less heart tissue at all dose levels between 5 and 80 Gy(RBE). The grade $ 3 RP rate for all patients was 8.1% (IMRT, 6.5%; PSPT, 10.5%); corresponding LF rates were 10.7% (all), 10.9% (IMRT), and 10.5% (PSPT). The posterior probability of IMRT being better than PSPT was 0.54. Exploratory analysis showed that the RP and LF rates at 12 months for patients enrolled before versus after the trial midpoint were 21.1% (before) versus 18.2% (after) for the IMRT group (P = .047) and 31.0% (before) versus 13.1% (after) for the PSPT group (P = .027). Conclusion PSPT did not improve dose-volume indices for lung but did for heart. No benefit was noted in RP or LF after PSPT. Improvements in both end points were observed over the course of the trial.

Concepts: Cancer, Metastasis, Oncology, Lung cancer, Cancer staging, Proton therapy, Prostate cancer, Radiation therapy


A randomized phase II study was performed to measure the potential therapeutic effects of yoga on fatigue, erectile dysfunction, urinary incontinence, and overall quality of life (QOL) in prostate cancer (PCa) patients undergoing external beam radiation therapy (RT).

Concepts: Medicine, Clinical trial, Cancer, Proton therapy, Prostate cancer, Urology, Radiation therapy, Hormonal therapy



: Proton therapy (PT) is a potentially promising, but costly, radiation modality. Assessment of such new health technologies is becoming increasingly important in the era of constrained budgets. This study attempts to establish how PT utilization might fit into the existing radiation oncology armamentarium.

Concepts: Medicine, Cancer, Proton therapy, Prostate cancer, Radiation therapy


To compare the grade 3 genitourinary toxicity and oncological outcome for localized prostate cancer between high-dose-rate (HDR) brachytherapy and external beam radiation therapy (EBRT) alone in patients with previously undergone Transurethral resection of the prostate (TURP).

Concepts: Cancer, Proton therapy, Prostate cancer, Urology, Radiation therapy, Brachytherapy, External beam radiotherapy, Transurethral resection of the prostate


Small field dosimetry is challenging due to the finite size of the conventional detectors that underestimate the dose distribution. With the fast development of the dynamic proton beam delivery system, it is essential to find a dosimeter which can be used for 3D dosimetry of small proton fields. We investigated the feasibility of using a proton formula PRESAGE® for 3D dosimetry of small fields in a uniform scanning proton beam delivery system with dose layer stacking technology. The relationship between optical density and the absorbed dose was found to be linear through small volume cuvette studies for both photon and proton irradiation. Two circular fields and three patient-specific fields were used for proton treatment planning calculation and beam delivery. The measured results were compared with the calculated results in the form of lateral dose profiles, depth dose, isodose plots and gamma index analysis. For the circular field study, lateral dose profile comparison showed that the relative PRESAGE® profile falls within ± 5% from the calculated profile for most of the spatial range. For unmodulated depth dose comparison, the agreement between the measured and calculated results was within 3% in the beam entrance region before the Bragg peak. However, at the Bragg peak, there was about 20% underestimation of the absorbed dose from PRESAGE®. For patient-specific field 3D dosimetry, most of the data points within the target volume passed gamma analysis for 3% relative dose difference and 3 mm distance to agreement criteria. Our results suggest that this proton formula PRESAGE® dosimeter has the potential for 3D dosimetry of small fields in proton therapy, but further investigation is needed to improve the dose under-response of the PRESAGE® in the Bragg peak region.

Concepts: Fundamental physics concepts, Particle physics, Proton therapy, Proton, Atom, Medical physics, Radiation oncology, Dose profile



INTRODUCTION:: Although many reports have shown the safety and efficacy of stereotactic body radiotherapy (SBRT) for T1N0M0 non-small-cell lung cancer (NSCLC), it is rather difficult to treat T2N0M0 NSCLC, especially T2b (>5 cm) tumor, with SBRT. Our hypothesis was that particle therapy might be superior to SBRT in T2 patients. We evaluated the clinical outcome of particle therapy for T2a/bN0M0 NSCLC staged according to the 7th edition of the International Union Against Cancer (UICC) tumor, node, metastasis classification. METHODS:: From April 2003 to December 2009, 70 histologically confirmed patients were treated with proton (n = 43) or carbon-ion (n = 27) therapy according to institutional protocols. Forty-seven patients had a T2a tumor and 23 had a T2b tumor. The total dose and fraction (fr) number were 60 (Gray equivalent) GyE/10 fr in 20 patients, 52.8 GyE/4 fr in 16, 66 GyE/10 fr in 16, 80 GyE/20 fr in 14, and other in four patients, respectively. Toxicities were scored according to the Common Terminology Criteria for Adverse Events, Version 4.0. RESULTS:: The median follow-up period for living patients was 51 months (range, 24-103). For all 70 patients, the 4-year overall survival, local control, and progression-free survival rates were 58% (T2a, 53%; T2b, 67%), 75% (T2a, 70%; T2b, 84%), and 46% (T2a, 43%; T2b, 52%), respectively, with no significant differences between the two groups. The 4-year regional recurrence rate was 17%. Grade 3 pulmonary toxicity was observed in only two patients. CONCLUSION:: Particle therapy is well tolerated and effective for T2a/bN0M0 NSCLC. To further improve treatment outcome, adjuvant chemotherapy seems a reasonable option, whenever possible.

Concepts: Cancer, Metastasis, Lung cancer, Non-small cell lung carcinoma, Cancer staging, Proton therapy, Prostate cancer, Adenocarcinoma


We investigated the association between external beam radiotherapy (EBRT) and pleural and peritoneal mesothelioma among long-term (>5 years) solid cancer survivors. We analyzed data from the US Surveillance, Epidemiology, and End Results (SEER) program (1973-2012). We fitted survival models adjusted by age, gender, race, year, surgery, and relative risk of primary mesothelioma in the county of residence (proxy for individual asbestos exposure). We estimated hazard ratios [HR] with reference to nonirradiated patients. We distinguished between scattered and direct irradiation to study the dose-response. We observed 301 mesotheliomas (265 pleural; 32 peritoneal; 4 others) among 935,637 patients. EBRT increased the risk of mesothelioma (any site; HR 1.34, 95% CI 1.04-1.77). We observed an increased risk of pleural mesothelioma (HR for EBRT 1.34, 95% CI 1.01-1.77), but we did not find signs of a dose-response relationship (HR for scattered irradiation 1.38; HR for direct irradiation 1.23). On the opposite, only direct peritoneal irradiation was associated with peritoneal mesothelioma (HR 2.20, 95% CI 0.99-4.88), particularly for latencies ≥10 years (HR 3.28, 95% CI 1.14-9.43). A competing risks analysis revealed that the clinical impact of radiation-induced mesothelioma was limited by the high frequency of competing events. The cumulative incidence function of mesothelioma after 40 years of observation was very low (nonirradiated patients 0.00032, irradiated patients 0.00055).EBRT might be a determinant of mesothelioma. Longer latency periods are associated with higher risks, while the dose-response seems nonlinear. The clinical impact of mesothelioma after EBRT for primary solid cancers is limited.

Concepts: Epidemiology, Cancer, Oncology, Food irradiation, Proton therapy, Radiation therapy, Mesothelioma, Asbestos