Goro Kasuya

A consensus-based guideline defining the clinical target volume for pelvic lymph nodes in external beam radiotherapy for uterine cervical cancer

OBJECTIVE To develop a consensus-based guideline as well as an atlas defining pelvic nodal clinical target volumes in external beam radiotherapy for uterine cervical cancer. METHODS A working subgroup to establish the consensus-based guideline on clinical target volumes for uterine cervical cancer was formulated by the Radiation Therapy Study Group of the Japan Clinical Oncology Group in July 2008. The working subgroup consisted of seven radiation oncologists. The process resulting in the consensus included a comparison of contouring on CT images among the members, reviewing of published textbooks and the relevant literature and a distribution analysis of metastatic nodes on computed tomography/magnetic resonance imaging of actual patients. RESULTS The working subgroup defined the pelvic nodal clinical target volumes for cervical cancer and developed an associated atlas. As a basic criterion, the lymph node clinical target volume was defined as the area encompassed by a 7 mm margin around the applicable pelvic vessels. Modifications were made in each nodal area to cover adjacent adipose tissues at risk of microscopic nodal metastases. Although the bones and muscles were excluded, the bowel was not routinely excluded in the definition. Each of the following pelvic node regions was defined: common iliac, external iliac, internal iliac, obturator and presacral. Anatomical structures bordering each lymph node region were defined for six directions; anterior, posterior, lateral, medial, cranial and caudal. Drafts of the definition and the atlas were reviewed by members of the JCOG Gynecologic Cancer Study Group (GCSG). CONCLUSIONS We developed a consensus-based guideline defining the pelvic node clinical target volumes that included an atlas. The guideline will be continuously updated to reflect the ongoing changes in the field.

Phase II Trial of Radiotherapy After Hyperbaric Oxygenation With Multiagent Chemotherapy (Procarbazine, Nimustine, and Vincristine) for High-Grade Gliomas: Long-Term Results

PURPOSE To analyze the long-term results of a Phase II trial of radiotherapy given immediately after hyperbaric oxygenation (HBO) with multiagent chemotherapy in adults with high-grade gliomas. METHODS AND MATERIALS Patients with histologically confirmed high-grade gliomas were administered radiotherapy in daily 2 Gy fractions for 5 consecutive days per week up to a total dose of 60 Gy. Each fraction was administered immediately after HBO, with the time interval from completion of decompression to start of irradiation being less than 15 minutes. Chemotherapy consisting of procarbazine, nimustine, and vincristine and was administered during and after radiotherapy. RESULTS A total of 57 patients (39 patients with glioblastoma and 18 patients with Grade 3 gliomas) were enrolled from 2000 to 2006, and the median follow-up of 12 surviving patients was 62.0 months (range, 43.2-119.1 months). All 57 patients were able to complete a total radiotherapy dose of 60 Gy immediately after HBO with one course of concurrent chemotherapy. The median overall survival times in all 57 patients, 39 patients with glioblastoma and 18 patients with Grade 3 gliomas, were 20.2 months, 17.2 months, and 113.4 months, respectively. On multivariate analysis, histologic grade alone was a significant prognostic factor for overall survival (p < 0.001). During treatments, no patients had neutropenic fever or intracranial hemorrhage, and no serious nonhematologic or late toxicities were seen in any of the 57 patients. CONCLUSIONS Radiotherapy delivered immediately after HBO with multiagent chemotherapy was safe, with virtually no late toxicities, and seemed to be effective in patients with high-grade gliomas.

External beam boost irradiation for clinically positive pelvic nodes in patients with uterine cervical cancer

The purpose of this study was to retrospectively analyze the treatment results of boost external beam radiotherapy (EBRT) to clinically positive pelvic nodes in patients with uterine cervical cancer. The study population comprised 174 patients with FIGO stages 1B1–4A cervical cancer who were treated with definitive radiotherapy (RT) or concurrent chemoradiotherapy (CCRT) and high-dose-rate intracavitary brachytherapy (HDR-ICBT). Patients with positive para-aortic or common iliac nodes (≥10 mm in the shortest diameter, as evaluated by CT/MRI) were ineligible for the study. Fifty-seven patients (33%) had clinically positive pelvic nodes. The median maximum diameter of the nodes was 15 mm (range, 10–60 mm) and the median number of positive lymph nodes was two (range, one to four). Fifty-two of 57 patients (91%) with positive nodes were treated with boost EBRT (6–10 Gy in three to five fractions). The median prescribed dose of EBRT for nodes was 56 Gy. The median follow-up time for all patients was 66 months (range, 3–142 months). The 5-year overall survival rate, disease-free survival rate and pelvic control rate for patients with positive and negative nodes were 73% and 92% (P = 0.001), 58% and 84% (P < 0.001), and 83% and 92% (P = 0.082), respectively. Five of 57 node-positive patients (9%) developed pelvic node recurrences. All five patients with nodal failure had concomitant cervical failure and/or distant metastases. No significant difference was observed with respect to the incidence or severity of late complications by application of boost EBRT. The current retrospective study demonstrated that boost EBRT to positive pelvic nodes achieves favorable nodal control without increasing late complications.

Distribution patterns of metastatic pelvic lymph nodes assessed by CT/MRI in patients with uterine cervical cancer

BackgroundTo investigate the three-dimensional (3D) distribution patterns of clinically metastatic (positive) lymph nodes on pretreatment computed tomography (CT)/magnetic resonance imaging (MRI) images of patients with locally advanced cervical cancer.MethodsWe enrolled 114 patients with uterine cervical cancer with positive nodes by CT/MRI (≥10 mm in the shortest diameter). Pretreatment CT/MRI data were collected at 6 institutions. The FIGO stage was IB1 in 2 patients (2%), IB2 in 6 (5%), IIA in 3 (3%), IIB in 49 (43%), IIIB in 50 (44%), and IVA in 4 (4%) patients. The median cervical tumor diameter assessed by T2-weighted MRI was 55 mm (range, 10–87 mm). The anatomical distribution of the positive nodes was evaluated on CT/MRI images by two radiation oncologists and one diagnostic radiologist.ResultsIn these patients, 273 enlarged nodes were assessed as positive. The incidence of positive nodes was 104/114 (91%) for the obturator region, 31/114 (27%) for the external iliac region, 16/114 (14%) for the internal iliac region, 22/114 (19%) for the common iliac region, and 6/114 (5%) for the presacral region. The external iliac region was subdivided into four sub-regions: lateral, intermediate, medial, and caudal. The obturator region was subdivided into two sub-regions: cranial and caudal. The majority of patients had positive nodes in the cranial obturator and/or the medial external iliac region (111/114). In contrast, few had positive nodes in the lateral external iliac, caudal external iliac, caudal obturator, internal iliac and presacral regions. All cases with positive nodes in those low-risk regions also had positive nodes in other pelvic nodal regions concomitantly. The incidence of positive nodes in the low-risk regions/sub-regions was significantly related to FIGO stage (p=0.017) and number of positive nodes (p<0.001).ConclusionsWe demonstrated the 3D distribution patterns of clinical metastatic pelvic lymph nodes on pretreatment CT/MRI images of patients with locally advanced cervical cancer. These findings might contribute to future individualization of the clinical target volume of the pelvic nodes in patients with cervical cancer.

SU-E-T-123: Dosimetric Comparison Between Portrait and Landscape Orientations in Radiochromic Film Dosimetry

PURPOSE To compare the dosimetric properties of radiochromic films with different orientation. METHODS A sheet of EBT3 film was cut into eight pieces with the following sizes: 15×15 cm2 (one piece), 5×15 cm2 (two) and 4×5 cm2 (five). A set of two EBT3 sheets was used at each dose level. Two sets were used changing the delivered doses (1 and 2 Gy). The 5×15 cm2 pieces were rotated by 90 degrees in relation to each other, such that one had landscape orientation and the other had portrait orientation. All 5×15 cm2 pieces were irradiated with their long side aligned with the x-axis of the radiation field. The 15×15 cm2 pieces were irradiated rotated at 90 degrees to each other. Five pieces, (a total of ten from two sheets) were used to obtain a calibration curve. The irradiated films were scanned using an Epson ES-2200 scanner and were analyzed using ImageJ software. In this study, no correction was applied for the nonuniform scanner signal that is evident in the direction of the scanner lamp. Each film piece was scanned both in portrait and landscape orientations. Dosimetric comparisons of the beam profiles were made in terms of the film orientations (portrait and landscape) and scanner bed directions (perpendicular and parallel to the scanner movement). RESULTS In general, portrait orientation exhibited higher noise than landscape and was adversely affected to a great extent by the nonuniformity in the direction of the scanner lamp. A significant difference in the measured field widths between the perpendicular and parallel directions was found for both oientations. CONCLUSION Without correction for the nonuniform scanner signal in the direction of the scanner lamp, a landscape orientation is preferable. A more detailed investigation is planned to evaluate quantitatively the effect of orientation on the dosimetric properties of a film.

SU-E-T-698: Fractal Analysis for Assessing IMRT Modulation Complexity

Purpose: To evaluate the feasibility of fractal dimension (FD as a modulation complexity metric in intensity modulated radiation therapy (IMRT) treatment fields. Methods: Uniform sliding window (SW) deliveries changing the leaf gap width (1–50 mm) were utilized for this study. During the SW deliver, the dynamic treatment log file (Dynalog file) was acquired. Binary images were produced from the DynaLog files of the sliding window fields. For each sliding window field, five binary images changing the pixel size (0.1, 0.2, 0.3, 0.4 and 0.5 mm) were produced. The FD was evaluated by the Box‐Counting method. The box sizes were 1, 2, 4, 8, 16 and 32 pixels. The fractal dimension for each segment and the overall field was evaluated by the averaging five images. In this study, FD is the average for all segments and the standard deviation of FD is the variation of FD between segments. The analysis was carried out by in‐house programming in ImageJ (http://imagej.nih.gov/ij/ ). A highly modulated field may Result in small leaf gaps, therefore low FD is expected for increased modulation complexity. Results: The FD decreases with the decrease of leaf gap width. The FDs and SDs were 1.964±0.0007, 1.879±0.0054, 1.816±0.0092, 1.402±0.0429 for 50, 10, 5, and 1 mm gap, respectively.The large SDs for small gap widths resulted from variability in leaf positions during the SW delivery. For 1 mm gap, a low FD value of 1.35 was observed at the middle segment where uneven leaf position could be observed visually. Conclusion: The FD for smaller leaf gap which implies highly modulated was lower. This work indicates that the FD method could be used for assessing IMRT plan complexity. Further studies such as comparison to other metrics and its usefulness in clinical IMRT plans are needed.

Risk Factors of Severe Late Complications in Patients with Uterine Cancer Treated with Postoperative Radiotherapy

AIM Severe late complications, particularly radiation enterocolitis and leg edema, remain major problems in patients with uterine cancer, who have undergone hysterectomy and postoperative external beam radiotherapy (EBRT). We carried out this retrospective analysis to identify the incidence of risk factors for such complications. PATIENTS AND METHODS The records of 228 patients, who underwent radical hysterectomy and postoperative EBRT (uterine cervix: 149 patients; uterine corpus: 79 patients) were reviewed retrospectively. The majority of the patients (90.8%) were treated with 50 to 50.4 Gy EBRT in conventional fractionations with anteroposterior fields. Intracavitary brachytherapy (ICBT) was administered to 9 patients (3.9%), and 35 patients (15.2%) received chemotherapy. The median follow-up for all 228 patients was 81.7 months (range, 1-273 months). RESULTS Nineteen patients (8.3%) developed severe radiation enterocolitis with a median latency of 12.6 months, and the ileum was the most frequently affected site. On multivariate analysis, smoking was an independent predictor of severe radiation enterocolitis. Nineteen patients (8.3%) developed severe leg edema with a median latency of 32.7 months. The degree of leg edema did not improve in any of the 19 patients despite intensive treatment. On multivariate analysis, addition of ICBT was an independent predictor of severe leg edema. CONCLUSION Severe radiation enterocolitis and severe leg edema were each observed in approximately 8% of patients with uterine cancer, who underwent postoperative radiotherapy. Severe radiation enterocolitis correlated strongly with smoking, and severe leg edema correlated strongly with addition of ICBT. These factors should be considered before administering postoperative radiotherapy to uterine cancer patients.