Delivery parameter variations and early clinical outcomes of volumetric modulated arc therapy for 31 prostate cancer patients: an intercomparison of three treatment planning systems.

We created volumetric modulated arc therapy (VMAT) plans for 31 prostate cancer patients using one of three treatment planning systems (TPSs)--ERGO++, Monaco, or Pinnacle--and then treated those patients. A dose of 74 Gy was prescribed to the planning target volume (PTV). The rectum, bladder, and femur were chosen as organs at risk (OARs) with specified dose-volume constraints. Dose volume histograms (DVHs), the mean dose rate, the beam-on time, and early treatment outcomes were evaluated and compared. The DVHs calculated for the three TPSs were comparable. The mean dose rates and beam-on times for Ergo++, Monaco, and SmartArc were, respectively, 174.3 ± 17.7, 149.7 ± 8.4, and 185.8 ± 15.6 MU/min and 132.7 ± 8.4, 217.6 ± 13.1, and 127.5 ± 27.1 sec. During a follow-up period of 486.2 ± 289.9 days, local recurrence was not observed, but distant metastasis was observed in a single patient. Adverse events of grade 3 to grade 4 were not observed. The mean dose rate for Monaco was significantly lower than that for ERGO++ and SmartArc (P < 0.0001), and the beam-on time for Monaco was significantly longer than that for ERGO++ and SmartArc (P < 0.0001). Each TPS was successfully used for prostate VMAT planning without significant differences in early clinical outcomes despite significant TPS-specific delivery parameter variations.

[Electronic portal image device dosimetry for volumetric modulated arc therapy].

Recently electronic portal image devices (EPIDs) have been widely used for quality assurance and dose verification. However there are no reports describing EPID dosimetry for Elekta volumetric modulated arc therapy (VMAT). We have investigated EPID dosimetry during VMAT delivery using a commercial software EPIDose with an Elekta Synergy linac. Dose rate dependence and the linac system sag during gantry rotation were measured. Gamma indices were calculated between measured doses using an EPID and calculation made by a treatment planning system for prostate VMAT test plans. The results were also compared to gamma indices using films and a two-dimensional detector array, MapCHECK2. The pass rates of the gamma analysis with a criterion of 3% and 2 mm for the three methods were over 96% with good consistency. Our results have showed that EPID dosimetry is feasible for Elekta VMAT.

[Quality assurance procedure for assessing mechanical accuracy of a radiation field center in stereotactic radiotherapy].

Stereotactic radiotherapy requires a quality assurance (QA) program that ensures the mechanical accuracy of a radiation field center. We have proposed a QA method for achieving the above requirement by conducting the Winston Lutz test using an electronic portal image device (EPID). An action limit was defined as three times the standard deviation. Then, the action limits for mean deviations of the radiation field center during collimator rotation, gantry rotation, and couch rotation in clockwise and counterclockwise resulted in 0.11 mm, 0.52 mm, 0.37 mm, and 0.41 mm respectively. Two years after the QA program was launched, the mean deviation of the radiation field center during gantry rotation exceeded the above action limit. Consequently, a mechanical adjustment for the gantry was performed, thereby restoring the accuracy of the radiation field center. A field center shift of 0.5 mm was also observed after a micro multi-leaf collimator was unmounted.

[Evaluation of new methods for removing moire artifact of radiochromic film].

An optical interference-pattern, a moire artifact, is produced during the film scanning process using a flatbed scanner. Images with moire artifacts include optical density fluctuations thereby leading to inaccuracy of measurement. In this study, we proposed two methods for removing moire artifacts from radiochromic film and compared dose response and profile as well as image resolution and size between our proposed methods versus the conventional process. The proposed methods could remove the artifacts without impairing dosimetric performance. It is expected that the proposed methods facilitate more accurate film dosimetry with reflective radiochromic films.

Prognostic significance of pretreatment 18F-fluorodeoxyglucose positron emission tomography evaluation using metabolic tumor volume of the primary tumor and lymph nodes in advanced hypopharyngeal cancer.

BACKGROUND: The purpose of this study was to retrospectively evaluate the usefulness of pretreatment positron emission tomography (PET) using metabolic tumor volume (MTV) of the primary tumor and lymph nodes in advanced hypopharyngeal cancer. METHODS: From June 2007 to December 2015, consecutive patients with advanced hypopharyngeal cancer who underwent PET and were treated with definitive radiation therapy were retrospectively reviewed. RESULTS: A total of 61 patients were eligible for this study. On multivariate analysis, MTV of the primary tumor (MTV-T) was significantly related to the local control rate and overall survival (OS) (P = .036 and .012, respectively). In patients with lower MTV-T, MTV of metastatic lymph nodes (MTV-N) was significantly related to disease-specific survival and OS (P = .012 and .017, respectively). CONCLUSION: MTV-T is a significant predictor in patients with advanced hypopharyngeal cancer, and MTV-N is also significant in patients with lower MTV-T.

Primary central nervous system lymphoma in Japan: changes in clinical features, treatment, and prognosis during 1985-2004.

We have conducted nationwide surveys of primary central nervous system lymphoma (PCNSL) treated since 1985. In the present study, we newly collected data between 2000 and 2004 and investigated changes in clinical features and outcome over time. A total of 739 patients with histologically proven PCNSL under going radiotherapy were analyzed. Seventeen institutions were surveyed, and data on 131 patients were collected. These data were compared with updated data that were previously obtained for 466 patients treated during 1985-1994 and 142 patients treated during 1995-1999. Recent trends toward decrease in male/female ratio, increase in aged patients, and increase in patients with multiple lesions were seen. Regarding treatment, decrease in attempts at surgical tumor removal and increases in use of systemic chemotherapy and methotrexate (MTX)-containing regimens were observed. The median survival time was 18, 29, and 24 months for patients seen during 1985-1994, 1995-1999, and 2000-2004, respectively, and the respective 5-year survival rates were 15%, 30%, and 30%. In groups seen during 1995-1999 and during 2000-2004, patients who received systemic or MTX-containing chemotherapy had better prognosis than those who did not. Multivariate analysis of all patients seen during 1985-2004 suggested the usefulness of MTX-containing chemotherapy as well as the importance of age, lactate dehydrogenase level, and tumor multiplicity as prognostic factors. Thus, this study revealed several notable changes in clinical features of PCNSL patients. The prognosis improved during the last 10 years. Advantage of radiation plus chemotherapy, especially MTX-containing chemotherapy, over radiation alone was suggested.

Treatment results of neoadjuvant chemoradiotherapy followed by radical esophagectomy in patients with initially inoperable thoracic esophageal cancer.

PURPOSE: We evaluated the effectiveness of neoadjuvant chemoradiotherapy (CRT) followed by esophagectomy for cT4 esophageal cancer or lymph node metastases (LNM) invading adjacent structures. MATERIALS AND METHODS: We retrospectively evaluated 42 consecutive patients with thoracic esophageal cancer who underwent CRT followed by esophagectomy between 2008 and 2013. All were initially considered to be unresectable because of cT4 (n = 32) disease or LN invasion (n = 10). Radiotherapy was administered at 41.4 Gy/23 fr with concurrent chemotherapy. At completion of CRT, restaging was performed using computed tomography (CT). RESULTS: All cT4 tumors were downstaged, LNM invading to adjacent structures were considered to be released, and subtotal esophagectomy was performed. The median follow-up period was 42 months. The curative resection (R0) rate was 94% in cT4 group and 70% in LN invasion group. The 3-year overall survival (OS) and 3-year locoregional control (LRC) rates were 65-80% in the cT4 group and 50-67% in LN invasion group, respectively. CONCLUSIONS: The cT4 group showed good rates of R0, OS, and LRC. Surgical resection should be an effective option when downstaging is achieved by CRT for patients with initially inoperable thoracic esophageal cancer.

Neoadjuvant Radiotherapy with Capecitabine Plus Bevacizumab for Locally Advanced Lower Rectal Cancer: Results of a Single-institute Phase II Study.

BACKGROUND/AIM: A single-arm phase II clinical trial was conducted to evaluate the safety and efficacy of adding bevacizumab to standard capecitabine-based neoadjuvant chemoradiotherapy (CRT) for the treatment of locally advanced rectal cancer (LARC). PATIENTS AND METHODS: Twenty-five patients were enrolled. Patients received capecitabine-based CRT for 5 weeks and 3 days. Bevacizumab was administered every 2 weeks during CRT. Within 6-10 weeks after completion of CRT, surgery was performed. RESULTS: With regard to CRT-related acute toxicities, most of the adverse events were limited to grade 1. A pathological complete response was obtained in four (16%) patients. In total, six patients (24%) developed postoperative complications. Six out of five (83%) patients healed without the need for surgical intervention. CONCLUSION: Although acute toxicity during CRT with bevacizumab was minimal and postoperative complications do not seem to increase, the addition of bevacizumab apparently offers no clinically-significant benefit for patients with LARC.

Dose Escalation Study of Concurrent Chemoradiotherapy With the Use of Involved-field Conformal Radiotherapy and Accelerated Hyperfractionation in Combination With Cisplatin and Vinorelbine Chemotherapy for Stage III Non-small Cell Lung Cancer: The Final Report.

OBJECTIVES: A phase I study to determine a recommended dose of thoracic radiotherapy using accelerated hyperfractionation for unresectable non-small cell lung cancer was conducted. MATERIALS AND METHODS: We used chemotherapy of a cisplatin doublet and 2 dose levels of radiation with accelerated hyperfractionation. The radiation dose levels were: a total dose of 60 Gy in 40 fractions at level 1, and 66 Gy in 44 fractions at level 2. Eligible patients with unresectable stage III non-small cell lung cancer received cisplatin and vinorelbine. Radiation therapy started on day 2 of chemotherapy and was delivered twice daily for 5 days a week. RESULTS: Total 12 patients were enrolled, with 6 patients each at dose levels 1 and 2. Dose-limiting toxicity was noted in 2 patients at level 1; one patient had grade 3 febrile neutropenia and the other patient had grade 3 esophagitis. No dose-limiting toxicity was noted in the 6 patients at level 2. Grade 3 to 4 leukopenia, neutropenia, and anemia were noted in 11 (92%), 9 (75%), and 8 (67%) of the total 12 patients, respectively. Grade 3 anorexia and infection were noted in 2 patients (17%) at each level. Grade 3 nausea, fatigue, esophagitis, and febrile neutropenia were noted in 1 patient (8%) at each level. The response rate in the total 12 patients was 83.3%. The median progression-free survival time and the median overall survival time were 10.7 and 24.2 months, respectively. CONCLUSIONS: Sixty-six gray in 44 fractions is the recommended dose for the following phase II study.

Correlations of post-implant regional dosimetric parameters at 24 hours and one month, with clinical results of low-dose-rate brachytherapy for localized prostate cancer.

PURPOSE: To evaluate the correlations of post-implant regional dosimetrics at 24 hours (24 h) and 1 month after implant procedures, with clinical outcomes of low-dose-rate (LDR) brachytherapy for localized prostate cancer. MATERIAL AND METHODS: Between January 2008 and December 2014, 130 consecutive patients treated for localized prostate cancer, receiving definitive iodine-125 (125I) brachytherapy treatment were retrospectively analyzed. All patients underwent post-implant CT imaging for dosimetric analysis at 24 h and 1 month after implantation procedure. Prostate contours were divided into quadrants: anterior-superior (ASQ), posterior-superior (PSQ), anterior-inferior (AIQ), and posterior-inferior (PIQ). Predictive factors and cut-off values of biochemical failure-free survival (BFFS) and toxicities of LDR brachytherapy were analyzed. RESULTS: The median follow-up time was 69.5 months. Seven patients (5.4%) had biochemical failure. The 3-year and 5-year BFFS rates were 96.7% and 93.1%, respectively. On multivariate analysis, prostate-specific antigen and Gleason score were significant prognostic factors for biochemical failure. D90 (the minimal dose received by 90% of the volume) of PSQ and PIQ at 24 h, and D90 of PSQ at 1 month were also significant factors. The cut-off values of PSQ D90 were 145 Gy at 24 h and 160 Gy at 1 month. D90 of the whole prostate was not significant at 24 h and at 1 month. D90 of PSQ at 1 month was a significant factor for rectal hemorrhage. CONCLUSIONS: Post-implant D90 of PSQ is significantly associated with BFFS for localized prostate cancer not only at 1 month, but also at 24 hours. D90 of PSQ at 1 month is also a significant factor for rectal hemorrhage.