M. Bonora

Image Guided Hypofractionated Radiotherapy and Quality of Life for Localized Prostate Cancer: Prospective Longitudinal Study in 337 Patients

PURPOSE We prospectively analyzed quality of life in a cohort of patients with prostate cancer undergoing a course of hypofractionated image guided radiotherapy. MATERIALS AND METHODS Between August 2006 and January 2011, 337 patients with a median age of 73 years who had cT1-T2N0M0 prostate cancer were eligible for this prospective, longitudinal study of hypofractionated image guided radiotherapy (70.2 Gy/26 fractions) using 1 of 3 image guided radiotherapy modalities (transabdominal ultrasound, x-ray or cone beam computerized tomography) available in our radiation oncology department. Patients completed 4 questionnaires before treatment, and 6, 12 and 24 months later, including the International Index of Erectile Function-5, International Prostate Symptom Score, and EORTC (European Organization for Research and Treatment of Cancer) prostate cancer specific QLQ-PR25 and QLQ-C30. RESULTS Patient followup was updated to at least the last questionnaire time point. Median followup was 19 months. Significant deterioration in erectile function on the International Index of Erectile Function-5 was documented with time only in patients without androgen deprivation (p = 0.0002). No change with time was observed in urinary symptom related quality of life on the QLQ-PR25 or International Prostate Symptom Score. Slight deterioration in QLQ-PR25 bowel symptom related quality of life was observed (p = 0.02). Overall QLQ-C30 Global Health Status improved with time (p = 0.03). On univariate analysis it significantly correlated with the maximum RTOG (Radiation Therapy Oncology Group)/EORTC urinary and bowel late toxicity scores after radiotherapy. CONCLUSIONS The regimen of hypofractionated image guided radiotherapy with multiple imaging modalities adopted in our radiation oncology department for localized prostate cancer might be a successful strategy for dose escalation with a limited impact on different aspects of quality of life with time.

[11C]Choline PET/CT Impacts Treatment Decision Making in Patients With Prostate Cancer Referred for Radiotherapy

BACKGROUND The purpose of our study was to analyze the role of [(11)C]choline-positron emission tomography/computed tomography (cho-PET/CT) in the management of patients with prostate cancer referred for radiotherapy. PATIENTS AND METHODS Inclusion criteria for this retrospective study were (1) presence of prostate cancer, (2) referral for first radiotherapy course (for primary or recurrent tumor) between February 2007 and July 2010, and (3) performance of cho-PET/CT. All cho-PET/CT scans were classified according to whether they were positive in the prostate/prostate bed (T), pelvic lymph nodes (N), and distant metastases (M) or negative. Therapeutic strategy based on the cho-PET/CT evaluation was compared with the strategy that would have been proposed had cho-PET/CT imaging not been available, following international and national prostate cancer guidelines. RESULTS Eighty-two cho-PET/CT scans performed in 74 patients were analyzed. Cho-PET/CT was positive in 49 studies (60%): T only in 22 (45% of all positive studies); N only in 4 (8%); T in combination with N in 3 (6%); and M in combination with T or N, or both, in 16 (33%). Treatment after positive cho-PET/CT examination included radiotherapy ± androgen deprivation (29 patients), surgery ± radiotherapy (6 patients), androgen deprivation only (8 patients), and other treatment (6 patients). In 22 cases, cho-PET/CT (27%) altered the treatment approach compared with the treatment that would have been adopted in the absence of cho-PET/CT analysis. CONCLUSION Cho-PET/CT is valuable in defining the extent of disease and supporting therapeutic decisions in the management of prostate cancer. The therapeutic strategy turned out to be influenced by cho-PET/CT imaging in about one third of the patients included in this study.

Dosimetric effects of residual uncertainties in carbon ion treatment of head chordoma

PURPOSE To investigate dose distribution variations due to setup errors and range uncertainties in image-guided carbon ion radiotherapy of head chordoma. MATERIALS AND METHODS Ten treatment plans were retrospectively tested with TRiP98 against ±1.0 mm and ±1.0° setup errors, as observed in clinical routine, and 2.6% range uncertainty when 2mm CTV-to-PTV margins were applied. Single-fraction simulations were compared with the total treatment dose in terms of DVH bands, conformity and inhomogeneity. The contribution of image processing artifacts on reported results was also discussed, as a function of the imaging dataset resolution. RESULTS Results showed that safety margins grant the conformal target coverage in presence of setup errors with D95(CTV) variations below 10% in 7 patients out of 10. Instead, the inclusion of range uncertainty yielded to appreciable dose degradation, reporting larger effects for CTV and dose conformity, whereas reduced impact is found on the organ-at-risk. The fractionation scheme positively affects dose conformity and inhomogeneity; conversely its influence on DVH bands is strongly related to the patient anatomy. CONCLUSION Besides safety margins, setup and range uncertainties lead to non-negligible combined contribution. Systematical treatment plan robustness assessment against expected uncertainties is thus encouraged, selecting beam settings and fractionation schemes where homogeneity is preserved.

Radiotherapy in Prostate Cancer Patients With Pelvic Lymphocele After Surgery: Clinical and Dosimetric Data of 30 Patients.

INTRODUCTION The purpose of the study was to evaluate the feasibility of irradiation after prostatectomy in the presence of asymptomatic pelvic lymphocele. PATIENTS AND METHODS The inclusion criteria for this study were: (1) patients referred for postoperative (adjuvant or salvage) intensity modulated radiotherapy (IMRT; 66-69 Gy in 30 fractions); (2) detection of postoperative pelvic lymphocele at the simulation computed tomography [CT] scan; (3) no clinical symptoms; and (4) written informed consent. Radiotherapy toxicity and occurrence of symptoms or complications of lymphocele were analyzed. Dosimetric data (IMRT plans) and the modification of lymphocele volume during radiotherapy (cone beam CT [CBCT] scan) were evaluated. RESULTS Between January 2011 and July 2013, in 30 of 308 patients (10%) treated with radiotherapy after prostatectomy, pelvic lymphocele was detected on the simulation CT. The median lymphocele volume was 47 cm(3) (range, 6-467.3 cm(3)). Lymphocele was not included in planning target volume (PTV) in 8 cases (27%). Maximum dose to lymphocele was 57 Gy (range, 5.7-73.3 Gy). Radiotherapy was well tolerated. In all but 2 patients, lymphoceles remained asymptomatic. Lymphocele drainage-because of symptom occurrence-had to be performed in 2 patients during IMRT and in one patient, 7 weeks after IMRT. CBCT at the end of IMRT showed reduction in lymphocele volume and position compared with the initial data (median reduction of 37%), more pronounced in lymphoceles included in PTV. CONCLUSION Radiotherapy after prostatectomy in the presence of pelvic asymptomatic lymphocele is feasible with acceptable acute and late toxicity. The volume of lymphoceles decreased during radiotherapy and this phenomenon might require intermediate radiotherapy plan evaluation.

MRI evaluation of sacral chordoma treated with carbon ion radiotherapy alone

BACKGROUND AND PURPOSE To compare RECIST 1.1 with volume modifications in patients with sacral chordoma not suitable for surgery treated with carbon ions radiotherapy (CIRT) alone. To evaluate patients pain before and after CIRT. To detect if baseline Apparent Diffusion Coefficient values (ADC) from Diffusion Weighted sequences could predict response to treatment. MATERIAL AND METHODS Patients included had one cycle of CIRT and underwent MRI before and after treatment. For each MRI, lesion maximum diameter and volume were obtained, and ADC values were analyzed within the whole lesion volume. Patients pain was evaluated with Numerical Rating Scale (NRS), considering the upper tumor level at baseline MRIs. RESULTS 39 patients were studied (mean follow-up 18 months). Considering RECIST 1.1 there was not a significant reduction in tumor diameters (p = 0.19), instead there was a significant reduction in tumor volume (p < 0.001), with a significant reduction in pain (p = 0.021) if the tumors were above vertebrae S2-S3 at baseline MRIs. The assessment of baseline ADC maps demonstrated higher median values and more negative skewness values in progressive disease (PD) patients versus both partial response (PR) and stable disease (SD). CONCLUSIONS Lesion volume measurement is more accurate than maximum diameter to better stratify the response of sacral chordoma treated with CIRT. Preliminary results suggest that baseline ADC values could be predictive of response to CIRT.

Risk of carotid blowout after reirradiation with particle therapy

Purpose Carotid blowout (CB) is a serious complication in retreatment of neoplasms in the head and neck (H&N) region. Rates seem to increase in hypofractionated or accelerated hyperfractionated regimens. In this study, we investigate the CB rate and the cumulative doses received by the carotid artery (CA) in a cohort of patients who were reirradiated at CNAO with particle therapy in the H&N region. Methods and materials The dosimetric information, medical records, and tumor characteristics of 96 patients were analyzed. For 49 of these patients, the quality of dosimetric information was sufficient to calculate the cumulative doses to the CA. The corresponding biological equivalent dose in 2 Gy fractions (EQD2) was calculated with an α/β-ratio of 3. Results In the final reirradiation at CNAO, 17 patients (18%) had been treated with protons and 79 (82%) with carbon ions. Two patients experienced profuse oronasal bleeding, of which one case was confirmed to be caused by CB. If attributing both cases to CB, we found an actuarial CB rate of 2.7%. Interestingly, there were no CB cases in the carbon ion group even though this was the large majority of patients and they generally were treated more aggressively in terms of larger fraction doses and higher cumulative EQD2. Conclusions The current practice of particle reirradiation at CNAO for recurrent neoplasms in the H&N region results in acceptable rates of CB.

EP-1759: Treatment of moving targets with active scanning carbon ion beams

performance testing and development of a micro-calorimeter based on Superconducting QUantum Interference Devices (SQUIDs) (1). Unlike other microdosimetric detectors that are used for investigating the energy distribution, this detector provides a direct measurement of energy deposition at the micrometer scale, that can be used to improve our understanding of biological effects in particle therapy application, radiation protection and environmental dosimetry. Temperature rises of less than 1μK are detectible and when combined with the low specific heat capacity of the absorber at cryogenic temperature, extremely high energy deposition sensitivity of approximately 0.4 eV can be achieved (2). The detector consists of 3 layers: a tissue equivalent (TE) absorber, a superconducting absorber and a silicon substrate. Ideally all energy would be absorbed in the TE absorber and heat rise in the superconducting layer would arise due to heat conduction from the TE layer. However, in practice direct particle absorption occurs in all 3 layers and must be corrected for. To investigate the thermal behavior within the detector, and quantify any possible correction, particle tracks were simulated employing Geant4 (v9.6) Monte Carlo simulations. The track information was then passed to the COMSOL Multiphysics (Finite Element Method) software. The 3D heat transfer within each layer was then evaluated in a timedependent model. For a statistically reliable outcome, the simulations had to be repeated for a large number of particles. An automated system has been developed that couples Geant4 Monte Carlo output to COMSOL for determining the expected distribution of proton tracks and their thermal contribution within the detector. Preliminary results of a 3.8 MeV proton beam showed that the detector reaches the equilibrium state after 8 ns. It is estimated that 20% of the temperature rise in the superconducting absorber is due to heat conduction from the adjacent absorber which needs to be corrected for. The simulations were repeated for proton beams with energies of 2, 10, 62 and 230 MeV.

OC-0250: Hadrontherapy as re-irradiation using active beam delivery at CNAO

Material and Methods: Between September 2013 and September 2015, data on 138 children (78 males, 60 females, aged 0.9-17.9 years (median 5.7 years)) were prospectively collected in KiProReg at WPE. Diagnoses were CNS tumours (n=73), sarcomas (n=59), extracranial germ cell tumors (n=3) and others (n=3), respectively. Treatment sites were brain (n=72), head and neck including base of skull (n=38), spine (n=15), or pelvis (n=13). In 73.9% of the patients, macroscopic residual disease was present before PT. The median total dose of PT was 54.0 Gy (range 29.8-74.0 Gy). Only two patients had a mixed beam technique. Due to the very young age, sedation was necessary in 55.1% of children. Concurrent chemotherapy was applied in 54.3% of children. Side-effects were classified according to Common Terminology Criteria for Adverse Events (CTCAE) V4.0 grading system.