M. De Ridder

Comparison of doxorubicin and mitoxantrone in the treatment of elderly patients with advanced diffuse non-Hodgkin's lymphoma using CHOP versus CNOP chemotherapy.

PURPOSE AND METHODSnA prospective, randomized, multicenter phase III trial was performed to investigate the feasibility of cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy in elderly patients ( > or = 60 years) with advanced non-Hodgkins lymphoma (NHL) of intermediate- and high-grade malignancy, and to compare the tolerance and efficacy of doxorubicin versus mitoxantrone (CHOP v CNOP).nnnRESULTSnOf 157 enrolled patients, 148 were eligible and 145 were assessable for response. Thirty-one percent of CNOP and 45% of CHOP patients completed six cycles without dose reduction. The cumulative normalized dose-intensity (NDI) was 92% with CHOP and 90% with CNOP after six cycles. The overall complete response (CR) rates were 49% and 31% in CHOP- and CNOP-treated patients, respectively (P = .03). Survival with CNOP was significantly worse as compared with CHOP (P = .03). Lymphoma-specific survival was significantly better in CHOP-treated patients (P = .034) At 3 years, 42% of CHOP and 26% of CNOP patients were alive. Additional unfavorable prognostic factors at diagnosis were high serum lactate dehydrogenase (LDH) level, bulky mass, and low performance status, but not age. The median disease-free intervals of complete responders were 27 (CHOP) and 15 (CNOP) months, respectively. Considering the complete group of patients, at 3 years 17% of CHOP and 13% of CNOP patients were alive and disease-free (P = .12). Common toxicity criteria (CTC) grade > or = 2 with CNOP and CHOP was not different.nnnCONCLUSIONnCHOP is well tolerated in elderly patients with advanced intermediate- or high-grade NHL and its NDI is not seriously impaired. Treatment with CHOP (doxorubicin) results in better CR and survival rates than CNOP (mitoxantrone). CHOP should be recommended for elderly patients with high-risk NHL.

Prognostic value of the lymph node ratio in node positive colon cancer

Surgery is the primary treatment of non-metastatic colon cancer. En bloc removal of the colon with its associated mesenteric lymph nodes is essential. However, the number of lymph nodes reported with colectomy varies widely and may be a result of variation in the actual number of regional lymph nodes, surgical technique, or the thoroughness of the pathologist in finding lymph nodes. The number of lymph node metastases is an important negative prognostic factor and is used in stratification schemes for clinical trials.1nnRecent studies have emphasised the fact that examining a greater number of nodes increases the likelihood of correct staging and is associated with better survival, after controlling …

Gating and tracking, 4D in thoracic tumours.

The limited ability to control for a tumours location compromises the accuracy with which radiation can be delivered to tumour-bearing tissue. The resultant requirement for larger treatment volumes to accommodate target uncertainty restricts the radiation dose because more surrounding normal tissue is exposed. With image-guided radiation therapy (IGRT), these volumes can be optimized and tumouricidal doses may be delivered, achieving maximum tumour control with minimal complications. Moreover, with the ability of high precision dose delivery and real-time knowledge of the target volume location, IGRT has initiated the exploration of new indications in radiotherapy such as hypofractionated radiotherapy (or stereotactic body radiotherapy), deliberate inhomogeneous dose distributions coping with tumour heterogeneity (dose painting by numbers and biologically conformal radiation therapy), and adaptive radiotherapy. In short: individualized radiotherapy. Tumour motion management, especially for thoracic tumours, is a particular problem in this context both for the delineation of tumours and organs at risk as well as during the actual treatment delivery. The latter will be covered in this paper with some examples based on the experience of the UZ Brussel. With the introduction of the NOVALIS system (BrainLAB, Feldkirchen, Germany) in 2000 and consecutive prototypes of the ExacTrac IGRT system, gradually a hypofractionation treatment protocol was introduced for the treatment of lung tumours and liver metastases evolving from motion-encompassing techniques towards respiratory-gated radiation therapy with audio-visual feedback and most recently dynamic tracking using the VERO system (BrainLAB, Feldkirchen, Germany). This evolution will be used to illustrate the recent developments in this particular field of research.

Phase II study of helical tomotherapy for oligometastatic colorectal cancer

BACKGROUNDnTo evaluate the efficacy and toxicity of helical tomotherapy in the treatment of oligometastatic colorectal cancer (CRC) patients who were not amenable for metastasectomy and/or (further) systemic treatment.nnnPATIENTS AND METHODSnCRC patients with five or less metastases were enrolled. No limitations concerning dimension or localization of the metastases were imposed. Patients were treated with intensity-modulated and image-guided radiotherapy using helical tomotherapy, delivering a total dose of 40 Gy in fractions of 4 Gy. Positron emission tomography-computed tomography (PET-CT) was carried out at baseline and 3 months after the initiation of radiotherapy to evaluate the metabolic response rate according to PET Response Criteria in Solid Tumors (PERCIST) version 1.0. Side-effects were scored using National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTC AE) version 3.0.nnnRESULTSnTwenty-three patients were enrolled. A total of 52 metastases were treated. One patient (4%) experienced grade 3 vomiting; two patients (9%) grade 2 diarrhea and dysphagia, respectively. Twenty-two patients were evaluated by post-treatment PET-CT. Five (23%) and seven patients (32%) achieved a complete and partial metabolic response, respectively, resulting in an overall metabolic response rate of 55%. The actuarial 1-year local control, progression-free survival, and overall survival were 54%, 25% and 86%, respectively.nnnCONCLUSIONnThe use of helical tomotherapy in oligometastatic CRC patients resulted in a promising metabolic response rate of 55%.

SU‐E‐J‐198: Evaluation of a Free‐Form Intensity‐Based Deformable Registration Method Using the POPI Model

PURPOSEnOur goal is to evaluate the accuracy of a free-form intensity-based deformable registration method using the POPI model.nnnMETHODSnFive subjects with 4DCT datasets from the POPI model (Vandemeulebrouke Med Phys 2011) were used to assess deformable registration accuracy. Each subject contained 100 or more identified landmark points that corresponded between the end-inspiratory and end-expiratory phases. The 0% phase was registered to the 50% phase first using a rigid alignment followed by a freeform intensity-based deformable registration. Landmark displacement was measured after the rigid registration (initial displacement) and the deformable registration (residual error). A single subject (POPI2) with significant initial displacement was also registered using an interactive tool to influence the deformation by locking local alignments to help guide the deformation. Error was measured with and without using the tool for this subject.nnnRESULTSnThe average initial displacement prior to deformable registration ranged from 5.7 mm to 14.0 mm. The mean (SD) residual error after deformation ranged from 1.0 mm (0.9) to 1.7 mm (3.3) for four of the five subjects. For POPI2 the initial residual deformable error was 4.6 mm (6.8). Using seven local alignments to guide the deformation the error for POPI2 decreased to 1.2 mm (1.0). The average error across all 5 subjects was 1.3 mm (2.0).nnnCONCLUSIONnA free-form intensity-based deformable registration method was found to provide good accuracy with an average error of 1.3 mm. A method for locally guided deformation allowed for the accurate registration of a challenging case with significant respiratory motion. References1. Vandemeulebrouke et al. Med Phys 2011.2. http://www.creatis.insa-lyon.fr/rio/popi-model/ AS Nelson is an employee with ownership at MIM Software, Inc. JW Piper is an employee with ownership at MIM Software, Inc.

WE‐G‐213CD‐03: A Dual Complementary Verification Method for Dynamic Tumor Tracking on Vero SBRT

PURPOSEnto use complementary cine EPID and gimbals log file analysis for in-vivo tracking accuracy monitoring.nnnMETHODSnA clinical prototype of dynamic tracking (DT) was installed on the Vero SBRT system. This prototype version allowed tumor tracking by gimballed linac rotations using an internal-external correspondence model. The DT prototype software allowed the detailed logging of all applied gimbals rotations during tracking. The integration of an EPID on the vero system allowed the acquisition of cine EPID images during DT. We quantified the tracking error on cine EPID (E-EPID) by subtracting the target center (fiducial marker detection) and the field centroid. Dynamic gimbals log file information was combined with orthogonal x-ray verification images to calculate the in-vivo tracking error (E-kVLog). The correlation between E-kVLog and E-EPID was calculated for validation of the gimbals log file. Further, we investigated the sensitivity of the log file tracking error by introducing predefined systematic tracking errors. As an application we calculate gimbals log file tracking error for dynamic hidden target tests to investigate gravity effects and decoupled gimbals rotation from gantry rotation. Finally, calculating complementary cine EPID and log file tracking errors evaluated the clinical accuracy of dynamic tracking.nnnRESULTSnA strong correlation was found between log file and cine EPID tracking error distribution during concurrent measurements (R=0.98). We found sensitivity in the gimbals log files to detect a systematic tracking error up to 0.5 mm. Dynamic hidden target tests showed no gravity influence on tracking performance and high degree of decoupled gimbals and gantry rotation during dynamic arc dynamic tracking. A submillimetric agreement between clinical complementary tracking error measurements was found.nnnCONCLUSIONSnRedundancy of the internal gimbals log file with x-ray verification images with complementary independent cine EPID images was implemented to monitor the accuracy of gimballed tumor tracking on Vero SBRT. Research was financially supported by the Flemish government (FWO), Hercules Foundation and BrainLAB AG.

OC-0500: A comparison of two clinical correlation models for dynamic tumor tracking with a focus on geometrical accuracy

A comparison of two clinical correlation models for dynamic tumor tracking with a focus on geometrical accuracy Jennifer Dhont, Master in Biomedical Engineering, 2014

PO-0791: Motion management and Vero dynamic tracking for SBRT in oligometastatic disease: a prospective trial

Sant’Orsola-Malpighi HospitalUniversity of Bologna, Radiation Oncology CenterDepartment of ExperimentalDiagnostic and Specialty Medicine DIMES, Bologna, Italy Sant’Orsola-Malpighi HospitalUniversity of Bologna, Department of Medical Physics, Bologna, Italy Fondazione di Ricerca e Cura “Giovanni Paolo II”Catholic University of Sacred Heart, Radiotherapy Unit, Campobasso, Italy Ospedale Bellaria, Radiotherapy Department, Bologna, Italy

PO-0854: Evaluation of a dedicated brain metastases treatment planning optimization for radiosurgery

S407 ________________________________________________________________________________ (PTV) was created adding a margin of 5 mm to the ITV .The dose distribution was optimized on the average CT prescribing a dose of 20 Gy per fraction delivering a total dose of 60 Gy to the PTV. The plans were calculated in a Phillips Pinnacle 9.10 planning system using conformal 3DRT and heterogeneity correction. The parameters obtained in the average CT optimized plan, were copied to the different image sets with identical monitor units to analyze the differences.

PV-0323: Prospective evaluation of markerless tumour tracking using 4D3D registration and dual energy imaging

Purpose or Objective: Four-dimensional cone-beam computed tomography (4D-CBCT) has great capability to provide volumetric and respiratory motion information with one gantry rotation. It is necessary to quantitatively assess, how difference of tumor displacement between actual and 4D-CBCT image exists. In this study, we evaluated the displacement of implanted fiducial markers assumed as tumor on fluoroscopic projection images and reconstructed 4D-CBCT images with different sorting methods.