Aya Harada

Supratentorial Glioblastoma Treated with Radiotherapy: Use of the Radiation Therapy Oncology Group Recursive Partitioning Analysis Grouping for Predicting Survival

OBJECTIVE This study aimed to evaluate the usefulness of recursive partitioning analysis model established by the Radiation Therapy Oncology Group for predicting the survival of patients with supratentorial glioblastoma treated with radiotherapy and to determine prognostic factors for the subgroups of this prognostic model. METHODS A total of 108 glioblastoma patients treated with radiotherapy between January 1987 and December 2005 were retrospectively reviewed. Recursive partitioning analysis classes III, IV, V and VI included 8, 29, 32 and 39 patients, respectively. These classes were divided into two subgroups: a good prognostic group containing classes III-IV and a poor prognostic group containing classes V-VI. The median radiation dose was 60 Gy. Seventy-five patients received chemotherapy and/or immunotherapy. RESULTS The overall survival differed significantly among classes III, IV, V and VI, with median survival times of 34, 15, 11 and 7 months, respectively. Among the good prognostic group, patients with basal ganglia invasion showed poorer survival outcomes than patients without basal ganglia invasion. Among the poor prognostic group, patients with tumor sizes of <5 cm and patients treated with nimustine hydrochloride showed better survival outcomes than those with tumor sizes of > or =5 cm and those without treatment with nimustine hydrochloride, respectively. CONCLUSIONS This study confirms the prognostic value of the recursive partitioning analysis grouping. Basal ganglia invasion could be a useful predictive factor for survival in the good prognostic group, whereas tumor size and treatment with nimustine hydrochloride could be useful predictive factors in the poor prognostic group.

Treatment outcomes of the patients with early glottic cancer treated with initial radiotherapy and salvaged by conservative surgery.

OBJECTIVE This retrospective study analyzed the oncological and treatment outcomes of the patients with T1-T2N0 glottic cancer, who were treated with radiotherapy as initial treatment and salvaged by conservative surgery for radiation failure. METHODS Between May 1999 and December 2010, 115 patients with glottic laryngeal cancer were treated at Kobe University Hospital. At presentation, 54 patients had stage T1a disease, 26 had stage T1b disease and 35 had stage T2 disease. Seventy-nine patients were treated with conventional radiotherapy and 36 patients were treated with hyperfractionated radiotherapy as initial treatment. RESULTS Median duration of follow-up was 61 months. Five-year local control rates of radiotherapy were 92% in T1a, 83% in T1b and 86% in T2. Of 12 patients who developed local recurrence, larynx was successfully preserved in 3 patients by laryngomicrosurgery, 7 patients by vertical partial laryngectomy and one patient by subtotal laryngectomy. Ultimate 5-year laryngeal preservation rate and local control rate of all cases were 99 and 100%, respectively. CONCLUSIONS Present results suggest that initial treatment with radiotherapy salvaged by organ preservation surgery is an effective strategy for laryngeal preservation in the treatment of T1-T2N0 glottic laryngeal cancer.

Dosimetric factors predicting radiation pneumonitis after CyberKnife stereotactic body radiotherapy for peripheral lung cancer

Objective: The aims of this study were to investigate the frequency of symptomatic radiation pneumonitis (RP) after CyberKnife lung stereotactic body radiotherapy (SBRT) and to evaluate predictive factors of symptomatic RP. Methods: 56 patients with peripheral non-small-cell lung cancer were treated using the CyberKnife® VSI™ System (Accuracy Inc., Sunnyvale, CA) between May 2013 and September 2015. Total radiation doses ranged from 48 to 56 Gy, as delivered in four equal fractions. Symptomatic RP was defined as a grade of ≥2. Predictive factors for symptomatic RP were evaluated using univariate and multivariate analyses. Results: With a median follow-up duration of 12.5 months (range, 3–27 months), symptomatic RP was observed in 6 (10.7%) of the 56 patients. In the univariate analysis, percent vital capacity (p < 0.05), maximum tumour diameter (p < 0.05), gross tumour volume (p < 0.05), planning target volume (p < 0.01), mean lung dose (p < 0.01) and a normal lung volume receiving 5–50 Gy of radiation (V5–50) (p < 0.01) were identified as significant predictive factors for symptomatic RP. In the multivariate analysis, only a V25 >3.4% (p = 0.011) was identified as a significant predictive factor of symptomatic RP. Conclusion: The incidence of symptomatic RP after CyberKnife SBRT was almost identical to the incidences reported in the linear accelerator-based SBRT. A significant association was observed between a V25 >3.4% and the risk of developing symptomatic RP. Advances in knowledge: This is the first report that has investigated prognostic factors for symptomatic RP after CyberKnife SBRT for lung cancer. The newly developed scoring system may help to predict symptomatic RP.

Stereotactic body radiotherapy for second primary lung cancer and intra-parenchymal lung metastasis in patients previously treated with surgery: evaluation of indications and predictors of decreased respiratory function

Abstract Background: The adaptation criteria for administration of stereotactic body radiotherapy (SBRT) to patients with lung cancer who previously underwent surgery and subsequently developed a second primary lung cancer (SPLC) or intra-parenchymal lung metastasis (IPLM) are controversial, unlike the criteria for repeat surgery. We aimed to evaluate the feasibility of SBRT for these patients. Factors associated with decreased respiratory function were also evaluated. Material and methods: Sixty-nine patients with 89 lesions who underwent SBRT between 2008 and 2017 were analyzed. Of these, 29 were diagnosed with SPLC while the remaining 40 had IPLM. The distribution of histological types was as follows: squamous cell carcinoma (n = 13 lesions); adenocarcinoma (n = 25); non-small cell carcinoma (n = 1); unknown histological type (n = 49). The prescribed doses to the planning target volume (PTV) were 50 Gy in five fractions for 85 lesions and 60 Gy in 10 fractions for four lesions at PTV mean. Results: Over a median follow-up period of 55 months, the 4-year overall survival and local control rates were 50.3% and 87.6%, respectively. Six patients experienced grade 2 radiation pneumonitis and one experienced grade 3. Two patients experienced grade 5 pulmonary fibrosis. Decreased respiratory function was observed in 10 patients (15.1%). On multivariate analysis, the presence of pulmonary disease before SBRT was the only statistically significant factor associated with decreased respiratory function. Conclusions: SBRT is safe and feasible in patients with SPLC or IPLM previously treated surgically. Pre-existing pulmonary disease was a predictive factor for decreased respiratory function.

Clinical log data analysis for assessing the accuracy of the CyberKnife fiducial-free lung tumor tracking system

PURPOSE The CyberKnife Xsight Lung Tracking (XLT) and 1-View tracking systems can synchronize beam targeting to a visible lung tumor with respiratory motion during irradiation without requiring internal fiducial markers. The systems use a correlation model that relates external marker positions to tumor positions as well as a prediction model that predicts the targets future position. In this study, the correlation and prediction model uncertainties related to the CyberKnife fiducial-free tumor tracking system were evaluated using clinical log data. METHODS AND MATERIALS Data from 211 fractions in 42 patients with lung tumors were analyzed. Log files produced by the CyberKnife Synchrony system were acquired after each treatment; the mean correlation and prediction errors for each patient were calculated. Additionally, we examined the tracking tumor-related parameters and analyzed the relationships between the model errors and tracking tumor-related parameters. RESULTS The overall means ± standard deviations (SDs) of the correlation errors were 0.70 ± 0.43 mm, 0.36 ± 0.16 mm, 0.44 ± 0.22 mm, and 0.95 ± 0.43 mm for the superoinferior (SI), left-right (LR), anteroposterior (AP), and radial directions, respectively. The overall means ± SDs of the prediction errors were 0.13 ± 0.11 mm, 0.03 ± 0.02 mm, 0.03 ± 0.02 mm, and 0.14 ± 0.11 mm for the SI, LR, AP, and radial directions, respectively. There were no significant differences in these errors between the XLT and 1-View tracking methods. The tumor motion amplitude was moderately associated with the correlation error and strongly related to the prediction error in the SI and radial directions. CONCLUSIONS Clinical log data analysis can be used to determine the necessary margin sizes in treatment plans to compensate for correlation and prediction errors in the CyberKnife fiducial-free lung tumor tracking system. The tumor motion amplitude may facilitate margin determination.

Investigation of the efficacy and safety of CyberKnife hypofractionated stereotactic radiotherapy for brainstem metastases using a new evaluation criterion: ‘symptomatic control’

Abstract The treatment of brainstem metastases remains a challenge as the brainstem itself is considered a neurological organ at risk. We aimed to investigate the efficacy and safety of CyberKnife hypofractionated stereotactic radiotherapy (HFSRT) for brainstem metastases, and to examine the balance between efficacy and safety for the management of neurological symptoms. A total of 26 lesions [pons (n = 18), medulla (n = 4) and midbrain (n = 4)] in 20 patients treated with CyberKnife hypofractionated stereotactic radiotherapy were retrospectively analyzed. The total radiation doses (18–30 Gy) were delivered in 3 or 5 equal fractions. The median follow-up was 6.5 (range, 0.5–38.0) months. The 6- and 12-month local control rates were 100% and 90%, respectively. Symptomatic failures, defined as the worsening and appearance of neurological symptoms due to the brainstem lesion after CyberKnife HFSRT, were observed in 6 patients [local failure (n = 1) and adverse events (n = 5). The symptomatic control and overall survival rates were 90% and 72% (after 6 months), respectively, and 76% and 53% (after 12 months), respectively. Longer symptomatic control was associated with site of lesion origin, and longer overall survival was associated with a graded prognostic assessment score of >2. To our knowledge, this is the second study to investigate the efficacy and safety of CyberKnife HFSRT for brainstem metastases. The local control rate was comparable with that of prior stereotactic radiosurgery studies. We propose a new evaluation criterion—‘symptomatic control’—to evaluate the efficacy and safety of brainstem radiotherapy.

A Dosimetric Comparison of Volumetric Modulated Arc Therapy (VMAT) with Unflattened Beams to VMAT with Flattened Beams and Tomotherapy for Head and Neck Cancer

Background: The purpose of this study was to compare the dose distributions and treatment delivery efficiency of volumetric modulated arc therapy (VMAT) with flattening filter free (FFF) beams (FFF-VMAT) against VMAT with flattening filter (FF) beams (FF-VMAT) and Helical TomoTherapy (HT) for head and neck cancer. Methods: Ten patients with nasopharyngeal and oropharyngeal cancer were chosen for this planning comparison study. Three treatment plans (dual arc FFF-VMAT, dual arc FF-VMAT, and HT) were created for each patient. The three prescription dose levels of the planning target volumes were 69.96, 60, and 54 Gy in 33 fractions, using the simultaneous integrated boost technique. Comparisons of the plan quality were performed by analyzing the homogeneity, conformity, dose to the organs at risk (OARs), the number of monitor units (MUs), and beam-on time (BOT) necessary for delivering the plans. Results: The target coverage and sparing of the OARs for FFF-VMAT were almost equivalent to those for FFVMAT and HT. Compared to FF-VMAT, FFF-VMAT and HT significantly increased the number of MUs. The BOTs were the same for FFF-VMAT and FF-VMAT but significantly increased for HT. Conclusion: We here present the first report of FFF-VMAT achieving a comparable plan quality with less delivery time to that of FF-VMAT and HT in head and neck cancer. FFF-VMAT is a highly efficient and feasible option for the treatment of head and neck cancer in clinical practice.