Enis Ozyar

Use of volumetric modulated arc radiotherapy in patients with early stage glottic cancer.

AIMS AND BACKGROUND We compared conformal, intensity-modulated radiotherapy (IMRT) and intensity-modulated arc therapy (IMAT) in early stage glottic cancer in terms of dosimetric features as target coverage, dose to the organs at risk and total treatment time. METHODS AND MATERIALS Five consecutive T1 glottic squamous cell carcinoma patients were selected for the study. Three-dimensional conformal radiotherapy (3D-CRT), 3-field or 5-field intensity-modulated radiotherapy (3F-IMRT and 5F-IMRT), or IMAT, which was in 2 different forms--a regular IMAT (R-IMAT) and an alternative IMAT (A-IMAT) with an unirradiated section, was planned for each patient. The prescribed dose was 63 Gy in 28 fractions. The minimum dose for 95% of the clinical target volume (D95), maximum dose point at clinical target volume (Dmax), total monitor units, left and right carotid artery doses (V35 and V50 - percentage of volume receiving 35 Gy and 50 Gy), and total treatment time were calculated for each plan. RESULTS Median D95 values in the 5 plans studied with each technique ranged between 63 and 63.3 Gy (P = NS). Median Dmax values for each technique ranged between 65.4 and 70.8 Gy. The number of hot spots with IMRT and IMAT was significantly higher than with 3D-CRT plans. Conformal radiotherapy plans median V35 (93.6%) and V50 (76.6-83.3%) values for carotid arteries were significantly higher than with IMRT and IMAT (2.9%-11.4% and 0.0%). Average treatment times for 3D-CRT, 3F-IMRT, 5F-IMRT, R-IMAT and A-IMAT techniques were calculated as 64, 119, 147, 39 and 32 seconds, respectively. CONCLUSIONS IMAT has significantly decreased the treatment time compared to IMRT and 3D-CRT with acceptable homogeneous clinical target volume coverage and low carotid dose.

Intensity modulated radiotherapy (IMRT) in bilateral retinoblastoma

Intensity modulated radiotherapy (IMRT) in bilateral retinoblastoma Background. External beam radiotherapy (EBRT) for retinoblastoma has traditionally been done with conventional radiotherapy techniques which resulted high doses to the surrounding normal tissues. Case report. A 20 month-old girl with group D bilateral retinoblastoma underwent intensity modulated radiotherapy (IMRT) to both eyes after failing chemoreduction and focal therapies including cryotherapy and transpupillary thermotherapy. In this report, we discuss the use of IMRT as a method for reducing doses to adjacent normal tissues while delivering therapeutic doses to the tumour tissues compared with 3-dimensional conformal radiotherapy (3DCRT). At one year follow-up, the patient remained free of any obvious radiation complications. Conclusions. Image guided IMRT provides better dose distribution than 3DCRT in retinoblastoma eyes, delivering the therapeutic dose to the tumours and minimizing adjacent tissue damage.

History of the Rare Cancer Network and past research

Approximately, twenty years ago, the Rare Cancer Network (RCN) was formed in Lausanne, Switzerland, to support the study of rare malignancies. The RCN has grown over the years and now includes 130 investigators from twenty-four nations on six continents. The network held its first international symposium in Nice, France, on March 21-22, 2014. The proceedings of that meeting are presented in two companion papers. This manuscript reviews the history of the growth of the RCN and contains the abstracts of fourteen oral presentations made at the meeting of prior RCN studies. From 1993 to 2014, 74 RCN studies have been initiated, of which 54 were completed, 10 are in progress or under analysis, and 9 were stopped due to poor accrual. Forty-four peer reviewed publications have been written on behalf of the RCN.

Treatment of olfactory neuroblastoma: a new approach

A 24-year-old male presented with a 6-month history of progressive left nasal obstruction, hypoanosmia, and discrete enophthalmos. As well, hypertension is present for years and peeling hands of palmar side 2–3 times a year during the winter months. Computed tomography and magnetic resonance imaging of the head showed an expansive mass in the left maxillary sinus of maximum oblique diameter 47 mm, extending into the nasal cavity (Fig. 1a). There was a partial dehiscence of the medial wall of the left maxillary sinus. Magnetic resonance angiography indicated a slightly higher caliber of maxillary artery on the left side and cervical artery angiography identified visible signs of pathological vascularization of the tumor mass, which comes from branches of the left maxillary artery and ophthalmic artery (Fig. 2). According to MRI examination, structure of tumor mass was nonhomogeneous, with numerous flow-voids that indicate the good vascularization. Intrusion of the mass through expanded sinus antrum was present in middle meatus. After application of contrast, intensive and easily nonhomogeneous staining was displayed. Endoscopic examination revealed a polypoid mass in the left nasal cavity and left maxillary sinus. The biopsy of lesion was indicated and performed under the general anesthesia and then the last tamponade was made because of massive hemorrhage which occurred during the procedure. Immunohistochemical analysis showed deposits of lobular tumors in the mucosa (Fig. 3). Tumor cells were relatively uniform, small scant cytoplasm, with some places formed pseudorosettes. Nucleus of tumor cells were round, there was no visible mitosis or nucleoluses. Blood vessels were dilated. There were no areas of necrosis. Cells were well-differentiated. Numerous rounded calcifications were found on the margins. Tumor cells were chromogranin and synaptophysin positive and analysis was detected olfactory neuroblastomagrade I (Hyams’ grading system, 1988). Described localization of tumor is atypical, since the most of the mass is in the maxillary sinus. This localization and expansion corresponds to Kadish Stage B. Embolization of maxillary and ophthalmic artery branches was performed to prevent a massive bleeding during operation. The 80 % of arteries lumen were embolized because the total lumen embolization could result with vision loss. A day after embolization, the patient was treated with endoscopic resection assisted by Caldwell-Luc with navigation under general anesthesia. The lesion in anterior and posterior ethmoidal regions was excised. Ethmoidal bone was skeletonized. There was no cerebrospinal fluid leak. Operation was performed with endoscopic transnasaltransmaxillar (Caldwell-Luc incision) approach. Tumor was excised subperiosteal and piecemeal. We did not perform a N. Vucinic (&) M. Eric Department of Anatomy, Faculty of Medicine, University of Novi Sad, Hajduk Veljkova 3, 21000 Novi Sad, Serbia e-mail: nikolavucinic87@gmail.com

In regard to Zhou et al "Baseline serum lactate dehydrogenase levels for patients treated with intensity-modulated radiotherapy for nasopharyngeal carcinoma: a predictor of poor prognosis and subsequent liver metastasis" (Int J Radiat Oncol Biol Phys 2012;82:e359-e365).

damage (8). Interestingly, the authors reported a toxicity profile for the patients treated with 50 Gy that is more compatible with the results presented by other teams referenced in this article. The important message provided by the authors is that too-high prescription and skin doses and large-volume implants lead to poor long-term cosmetic results after APBI using IB. However, using adequate technique, treatment planning, dose prescription, and total dose, IB is a safe modality to provide APBI to selected patients (9).

Treatment outcome and prognostic factors for adult patients with medulloblastoma: The Rare Cancer Network (RCN) experience

BACKGROUND AND PURPOSE The optimal treatment for adults with newly diagnosed medulloblastoma (MB) has not been defined. We report a large series of cases from the Rare Cancer Network. MATERIAL AND METHODS Thirteen institutions enrolled 206 MB patients who underwent postoperative radiotherapy (RT) between 1976 and 2014. Log-rank univariate and Cox-modeled multivariate analyses were used to analyze data collected. RESULTS Median patient age was 29 years; follow-up was 31 months. All patients had the tumor resected; surgery was complete in 140 (68%) patients. Postoperative RT was given in 202 (98%) patients, and 94% received craniospinal irradiation (CSI) and, usually, a posterior fossa boost. Ninety-eight (48%) patients had chemotherapy, mostly cisplatin and vincristine-based. The 10-year local control, overall survival, and disease-free survival rates were 46%, 51%, and 38%, respectively. In multivariate analyses, Karnofsky Performance Status (KPS) ≥80 and CSI were significant for disease-free and overall survival (P ≤ .04 for all); receiving chemotherapy and KPS ≥80 correlated with better local-control rates. CONCLUSIONS Patients with high KPS who received CSI had better rates of disease-free and overall survival. Chemotherapy was associated with better local control. These results may serve as a benchmark for future studies designed to improve outcomes for adults with medulloblastoma.

Improvement of conformal arc plans by using deformable margin delineation method for stereotactic lung radiotherapy

Abstract Purpose Stereotactic body radiotherapy (SBRT) is an established treatment technique in the management of medically inoperable early stage non–small cell lung cancer (NSCLC). Different techniques such as volumetric modulated arc (VMAT) and three‐dimensional conformal arc (DCA) can be used in SBRT. Previously, it has been shown that VMAT is superior to DCA technique in terms of plan evaluation parameters. However, DCA technique has several advantages such as ease of use and considerable shortening of the treatment time. DCA technique usually results in worse conformity which is not possible to ameliorate by inverse optimization. In this study, we aimed to analyze whether a simple method – deformable margin delineation (DMD) – improves the quality of the DCA technique, reaching similar results to VMAT in terms of plan evaluation parameters. Methods Twenty stage I–II (T1‐2, N0, M0) NSCLC patients were included in this retrospective dosimetric study. Noncoplanar VMAT and conventional DCA plans were generated using 6 MV and 10 MV with flattening filter free (FFF) photon energies. The DCA plan with 6FFF was calculated and 95% of the PTV was covered by the prescription isodose line. Hot dose regions (receiving dose over 100% of prescription dose) outside PTV and cold dose regions (receiving dose under 100% of prescription dose) inside PTV were identified. A new PTV (PTV‐DMD) was delineated by deforming PTV margin with respect to hot and cold spot regions obtained from conventional DCA plans. Dynamic multileaf collimators (MLC) were set to PTV‐DMD beam eye view (BEV) positions and the new DCA plans (DCA‐DMD) with 6FFF were generated. Three‐dimensional (3D) dose calculations were computed for PTV‐DMD volume. However, the prescription isodose was specified and normalized to cover 95% volume of original PTV. Several conformity indices and lung doses were compared for different treatment techniques. Results DCA‐DMD method significantly achieved a superior conformity index (CI), conformity number (CIP addick), gradient index (R50%), isodose at 2 cm (D2 cm) and external index (CΔ) with respect to VMAT and conventional DCA plans (P < 0.05 for all comparisons). CI ranged between 1.00–1.07 (Mean: 1.02); 1.00–1.18 (Mean: 1.06); 1.01–1.23 (Mean 1.08); 1.03–1.29 (Mean: 1.15); 1.04–1.29 (Mean: 1.18) for DCA‐DMD‐6FFF, VMAT‐6FFF, VMAT‐10FFF DCA‐6FFF and DCA‐10FFF respectively. DCA‐DMD‐6FFF technique resulted significantly better CI compared to others (P = 0.002; < 0.001; < 0.001; < 0.001). R50% ranged between 3.22–4.74 (Mean: 3.99); 3.24–5.92 (Mean: 4.15) for DCA‐DMD‐6FFF, VMAT‐6FFF, respectively. DCA‐DMD‐6FFF technique resulted lower intermediate dose spillage compared to VMAT‐6FFF, though the difference was statistically insignificant (P = 0.32). D2 cm ranged between 35.7% and 67.0% (Mean: 53.2%); 42.1%–79.2% (Mean: 57.8%) for DCA‐DMD‐6FFF, VMAT‐6FFF respectively. DCA‐DMD‐6FFF have significantly better and sharp falloff gradient 2 cm away from PTV compared to VMAT‐6FFF (P = 0.009). CΔ ranged between 0.052 and 0.140 (Mean: 0.085); 0,056–0,311 (Mean: 0.120) for DCA‐DMD, VMAT‐6FFF, respectively. DCA‐DMD‐6FFF have significantly improved CΔ (P = 0.002). VMAT‐ V20 Gy, V2.5 Gy and mean lung dose (MLD) indices are calculated to be 4.03%, 23.83%, 3.42 Gy and 4.19%, 27.88%,3.72 Gy, for DCA‐DMD‐6FFF and DCA techniques, respectively. DCA‐DMD‐6FFF achieved superior lung sparing compared to DCA technique. DCA‐DMD‐6FFF method reduced MUs 44% and 33% with respect to VMAT‐6FFF and 10FFF, respectively, without sacrificing dose conformity (P < 0.001; P < 0.001). Conclusions Our results demonstrated that DCA plan evaluation parameters can be ameliorated by using the DMD method. This new method improves DCA plan quality and reaches similar results with VMAT in terms of dosimetric parameters. We believe that DCA‐DMD is a simple and effective technique for SBRT and can be preferred due to shorter treatment and planning time.

Robotic radiosurgery of head and neck paragangliomas: a single institution experience

CyberKnife® is a robotic stereotactic radiotherapy system. The aim of this study is to evaluate the effectiveness and the safety of CyberKnife® on treating head and neck paragangliomas and to report our results.

In Regard to Hauptman et al

To the Editor: In their paper, Hauptman et al (1) report their experience managing low-grade cranial chordomas and chondrosarcomas of the skull base with both conventionally fractionated linear accelerator-based stereotactic radiation therapy (SRT, nZ10) and single-fraction stereotactic radiosurgery (SRS, nZ5) (1). Although the authors do a very good job of describing the UCLA experience, no mention is made of an equally important emerging radiation treatment, hypofractionated robotic radiation therapy (R-SRT) (2-4). Gwak et al (2) reported their preliminary results in 9 patients previously treated with radiation therapy or SRS, using doses which ranged from 21 to 43.6 Gy in 3 to 5 fractions. After a median follow up of 24 months, disease progression was noted in only 1 patient. Meanwhile, Cheshier et al (3) reported Stanford University R-SRT experience in treating 35 lesions of the foramen magnum, including 2 chordoma and chondrosarcoma. The fractionation schedule (mean, 1.8 sessions; range, 1-5 sessions) varied with the size of the treated lesion, but the mean dose administered was 19 Gy. Finally, Henderson et al (4) reported the Georgetown experience using RSRT in 18 patients with chordoma and chondrosarcoma involving either the spine or skull base. Within this group of patients, a 59% local control rate (based on imaging) was observed at 65 months; in that study, all 3 major complications occurred in previously irradiated cases. In addition, the analysis by Henderson et al (4) suggested an alpha:beta ratio of 2.45 for chordoma, which further supports the argument for using hypofractionation in such cases. In each of the above papers, it was concluded that R-SRT was an effective treatment with an acceptable rate of complications. Given the small size of the above-mentioned studies and relatively limited length of follow-up, it is impossible to determine how successful R-SRT can ultimately be for treating skull base chordoma and chondrosarcoma. Nevertheless, the outcomes with R-SRT, a still very emergent therapy, reported to date are intriguing. In addition, the unique radiobiology of chordoma and chondrosarcoma argues strongly for a hypofractionated approach. Ultimately, with greater experience, it is possible that R-SRT may prove to be every bit as effective and safe as alternative radiation regimens, even including heavy particle treatments.