Dose prescription in SBRT for early-stage non-small cell lung cancer: are we all speaking the same language?

INTRODUCTION: Stereotactic body radiation therapy is increasingly used in the treatment of early-stage lung cancers. Guidelines provide indications regarding the constraints to the organs at risk (OARs) and the minimum coverage of the planning target volume but do not suggest optimal dose distribution. Data on dose distribution from the different published series are not comparable due to different prescription modalities and reported dose parameters. METHODS: We conducted a review of the published data on dose prescription, focusing on the role of homogeneity on local tumor control, and present suggestions on how to specify and report the prescriptions to permit comparisons between studies or between cases from different centers. CONCLUSIONS: To identify the dose-prescription modality that better correlates with oncologic outcomes, future studies should guarantee a close uniformity of dose distribution between cases and complete dose parameters reporting for treatment volumes and OARs.

Computed Tomography to Cone Beam Computed Tomography Deformable Image Registration for Contour Propagation Using Head and Neck, Patient-Based Computational Phantoms: A Multicenter Study.

PURPOSE: To investigate the performance of various algorithms for deformable image registration (DIR) for propagating regions of interest (ROIs) using multiple commercial platforms, from computed tomography to cone beam computed tomography (CBCT) and megavoltage computed tomography. METHODS AND MATERIALS: Fourteen institutions participated in the study using 5 commercial platforms: RayStation (RaySearch Laboratories, Stockholm, Sweden), MIM (Cleveland, OH), VelocityAI and SmartAdapt (Varian Medical Systems, Palo Alto, CA), and ABAS (Elekta AB, Stockholm, Sweden). Algorithms were tested on synthetic images generated with the ImSimQA (Oncology Systems Limited, Shrewsbury, UK) package by applying 2 specific deformation vector fields (DVF) to real head and neck patient datasets. On-board images from 3 systems were used: megavoltage computed tomography from Tomotherapy and 2 kinds of CBCT from a clinical linear accelerator. Image quality of the system was evaluated. The algorithms' accuracy was assessed by comparing the DIR-mapped ROIs returned by each center with those of the reference, using the Dice similarity coefficient and mean distance to conformity metrics. Statistical inference on the validation results was carried out to identify the prognostic factors of DIR performance. RESULTS: Analyzing 840 DIR-mapped ROIs returned by the centers, it was demonstrated that DVF intensity and image quality were significant prognostic factors of DIR performance. The accuracy of the propagated contours was generally high, and acceptable DIR performance can be obtained with lower-dose CBCT image protocols. CONCLUSIONS: The performance of the systems proved to be image quality specific, depending on the DVF type and only partially on the platforms. All systems proved to be robust against image artifacts and noise, except the demon-based software.

Performance of commercially available deformable image registration platforms for contour propagation using patient-based computational phantoms: A multi-institutional study.

PURPOSE: To investigate the performance of various algorithms for deformable image registration (DIR) to propagate regions of interest (ROIs) using multiple commercial platforms. METHODS AND MATERIALS: Thirteen institutions participated in the study with six commercial platforms: RayStation (RaySearch Laboratories, Stockholm, Sweden), MIM (Cleveland, OH, USA), VelocityAI and Smart Adapt (Varian Medical Systems, Palo Alto, CA, USA), Mirada XD (Mirada Medical Ltd, Oxford, UK), and ABAS (Elekta AB, Stockholm, Sweden). The DIR algorithms were tested on synthetic images generated with the ImSimQA package (Oncology Systems Limited, Shrewsbury, UK) by applying two specific Deformation Vector Fields (DVF) to real patient data-sets. Head-and-neck (HN), thorax, and pelvis sites were included. The accuracy of the algorithms was assessed by comparing the DIR-mapped ROIs from each center with those of reference, using the Dice Similarity Coefficient (DSC) and Mean Distance to Conformity (MDC) metrics. Statistical inference on validation results was carried out in order to identify the prognostic factors of DIR performances. RESULTS: DVF intensity, anatomic site and participating center were significant prognostic factors of DIR performances. Sub-voxel accuracy was obtained in the HN by all algorithms. Large errors, with MDC ranging up to 6 mm, were observed in low-contrast regions that underwent significant deformation, such as in the pelvis, or large DVF with strong contrast, such as the clinical tumor volume (CTV) in the lung. Under these conditions, the hybrid DIR algorithms performed significantly better than the free-form intensity based algorithms and resulted robust against intercenter variability. CONCLUSIONS: The performances of the systems proved to be site specific, depending on the DVF type and the platforms and the procedures used at the various centers. The pelvis was the most challenging site for most of the algorithms, which failed to achieve sub-voxel accuracy. Improved reproducibility was observed among the centers using the same hybrid registration algorithm.

Tailored intraoperative localization of non-palpable pulmonary lesions for thoracoscopic wedge resection using hybrid room technology.

INTRODUCTION: VATS wedge resection can require conversion to thoracotomy when pulmonary lesions cannot be identified. Hybrid operating rooms (HORs) provide real-time image acquisition capabilities allowing the intraoperative placement of markers to facilitate the removal of non-palpable nodules during VATS. OBJECTIVES: To present our workflow based on the alternative use of two different markers according to the location of the lung lesion and report our initial results. METHODS: All consecutive patients with non-palpable lesions requiring VATS wedge resection underwent localization of the targets in HOR. Lesions were considered non-palpable if they were small (<1 cm), deep (>1 cm from surface), subsolid, or located within a dystrophic area. Anesthetized patients were placed in lateral decubitus. Cone-beam CT (CBCT) was performed, and the needle trajectory was planned using Syngo iGuide Needle Guidance. Metal hook-wire or coil was placed, according to our workflow, close to the lesion and their position was verified by CBCT or fluoroscopy. RESULTS: Eleven VATS wedge resections were performed in 10 patients with 12 non-palpable lesions. The localization was performed with seven hook-wires and four coils in 30 minutes (range 17-56 minutes). The median estimated total effective dose was 11.6 mSv (range 1.9-24.7 mSv). Eleven lesions were removed by VATS, and one deep nodule required a thoracotomy. No complications were observed. CONCLUSIONS: Our experience confirms that HOR is suitable for simultaneous localization and VATS resection of 'difficult' pulmonary lesions. A versatile approach, using different devices, seems advisable for the removal of targets in every clinical scenario, reducing the VATS conversion rate.

Evaluation of antibody-dependent cell-mediated cytotoxicity activity and cetuximab response in KRAS wild-type metastatic colorectal cancer patients.

AIM: To investigate the prognostic role of invariant natural killer T (iNKT) cells and antibody-dependent cell-mediated cytotoxicity (ADCC) in wild type KRAS metastatic colorectal cancer (mCRC) patients treated with cetuximab. METHODS: Forty-one KRAS wt mCRC patients, treated with cetuximab and irinotecan-based chemotherapy in II and III lines were analyzed. Genotyping of single nucleotide polymorphism (SNP)s in the FCGR2A, FCGR3A and in the 3' untranslated regions of KRAS and mutational analysis for KRAS, BRAF and NRAS genes was determined either by sequencing or allelic discrimination assays. Enriched NK cells were obtained from lymphoprep-peripheral blood mononuclear cell and iNKT cells were defined by co-expression of CD3, TCRVα24, TCRVß11. ADCC was evaluated as ex vivo NK-dependent activity, measuring lactate dehydrogenase release. RESULTS: At basal, mCRC patients performing ADCC activity above the median level (71%) showed an improved overall survival (OS) compared to patients with ADCC below (median 16 vs 8 mo; P = 0.026). We did not find any significant correlation of iNKT cells with OS (P = 0.19), albeit we observed a trend to a longer survival after 10 mo in patients with iNKT above median basal level (0.382 cells/microliter). Correlation of OS and progression-free survival (PFS) with interesting SNPs involved in ADCC ability revealed not to be significant. Patients carrying alleles both with A in FCGR2A and TT in FCGR3A presented a trend of longer PFS (median 9 vs 5 mo; P = 0.064). Chemotherapy impacted both iNKT cells and ADCC activity. Their prognostic values get lost when we analysed them after 2 and 4 mo of treatment. CONCLUSION: Our results suggest a link between iNKT cells, basal ADCC activity, genotypes in FCGR2A and FCGR3A, and efficacy of cetuximab in KRAS wt mCRC patients.

Eribulin in pretreated metastatic breast cancer patients: results of the TROTTER trial-a multicenter retrospective study of eribulin in real life.

This retrospective multicenter analysis was aimed to evaluate clinical activity and tolerability of eribulin in pretreated metastatic breast cancer patients in clinical practice. Patients treated with eribulin from January 2012 to July 2013 were enrolled in the observational study from 10 italian hospitals. Tumor and toxicity evaluation were performed according to Agenzia Italiana Farmaco. One-hundred and thirteen patients were included in the study. Median age 62 years old. 71.7 % of the patients had visceral involvement and the majority had a burden of disease involving two or more organs with a median number of 2 (1-6). The median number of previous chemotherapy regimens for advanced disease was 3 (1-10). Median number of eribulin cycles was 4 (1-27). Overall response rate was 24 % (95 % CI 16.0-31.8). Clinical benefit rate, was 35.4 % (95 % CI 26.6-44.2). At a median follow-up of 29.6 months (8.3-41.9) the median progression free survival was 3.3 months (0.6-26.7; 95 % CI 2.4-4.2), and the median overall survival 11.6 months (0.6-33.3; 95 % CI 8.7-14.5). No correlation was recorded between subtypes in terms of ORR and CBR. Toxicity was manageable. Main common grade 3-4 toxicities were neutropenia (19.4 %), febrile neutropenia (0.9 %), asthenia (3.5 %), abnormal liver function test (1.8 %), stomatitis (0.9 %). Our results confirm that treatment with eribulin is feasible and safe in real-world patients.

Facial Basal Cell Carcinomas in Elderly Frail Patients Treated with Low Total-dose Radiotherapy.

AIM: A retrospective analysis was performed in our two Institutions in order to evaluate the feasibility and reliability of a hypofractionated-radiotherapy regimen in the treatment of frail elderly patients with facial basal cell carcinomas (BCCs). PATIENTS AND METHODS: The records of elderly patients (age >75 years) with histologically-confirmed BCC, T1-2, treated to a total radiation dose of 25-30 Gy over 5-6 weeks, were retrospectively analyzed. RESULTS: From February 2007-December 2010, 134 ambulatory patients with 159 BCCs were treated. Their median age was 82.5 years (range=75-103). Grade 1-2 skin acute toxicities were observed in 30.6% of patients (41/134). Complete responses were observed in 157 tumors in 132 patients. At the last follow-up, June 2014, no late toxicities had been noted; three patients had local recurrent disease. CONCLUSION: Our results seem to demonstrate both the feasibility and efficacy of curative hypofractionated radiation therapy in elderly patients with BCCs unfit for daily irradiation.

Reliability of prostate-specific antigen-marker in determining biochemical failure during the first 2 years after external beam radiation therapy and hormone therapy in patients with non-operated prostate cancer.

OBJECTIVES: The presence of prostate-specific antigen (PSA)-bounce after external beam radiation therapy (EBRT) and hormone therapy (HT) makes PSA an unreliable marker in determining PSA biochemical failure (PSA-BF) during the first 2 years after EBRT + HT in patients with non-operated prostate cancer (CaP). To determine the reliability of PSA-BF in predicting clinical outcomes, the Kamat definition, which does not consider PSA-BF during the first 24 months after EBRT, was tested against three other more frequently used methods (American Society of Radiation Oncology, Vancouver, and American Society of Radiation Oncology-Phoenix), which do. Secondly, their relative accuracies in predicting the clinical outcomes were also calculated. MATERIALS AND METHODS: In January 2011, 193 consecutive CaPs, treated with radical EBRT + HT in our institution from 1999 to 2002, were retrospectively investigated. BF was calculated according to the Kamat definition against the other three above-mentioned methods. Each BF-free survival was analyzed in function of every clinical endpoint (clinical-failure-free survival, cause specific survival, and overall survival) using univariate and multivariate Cox regression analyses. The accuracy of each definition in predicting clinical relapse was also calculated and compared. RESULTS: Only the Kamat BF definition had both a significant Cox hazard ratio, regarding clinical events or cancer deaths, and the best accuracy values in predicting clinical outcomes. Retrospective study design was the major limitation of the study. CONCLUSIONS: Only the Kamat definition, which does not consider PSA-BF during the first 24 months after EBRT + HT, was shown to be a reliable predictor of clinical events. Thus, our results suggest that solely PSA-based BF should not be considered as a reliable surrogate endpoint during the first 24 months after EBRT + HT. Consequently, caution should be used in adopting rescue treatment without further work-up on an individual basis.

A new approach for the pixel map sensitivity (PMS) evaluation of an electronic portal imaging device (EPID).

When using an electronic portal imaging device (EPID) for dosimetric verifications, the calibration of the sensitive area is of paramount importance. Two calibration methods are generally adopted: one, empirical, based on an external reference dosimeter or on multiple narrow beam irradiations, and one based on the EPID response simulation. In this paper we present an alternative approach based on an intercalibration procedure, independent from external dosimeters and from simulations, and is quick and easy to perform. Each element of a detector matrix is characterized by a different gain; the aim of the calibration procedure is to relate the gain of each element to a reference one. The method that we used to compute the relative gains is based on recursive acquisitions with the EPID placed in different positions, assuming a constant fluence of the beam for subsequent deliveries. By applying an established procedure and analysis algorithm, the EPID calibration was repeated in several working conditions. Data show that both the photons energy and the presence of a medium between the source and the detector affect the calibration coefficients less than 1%. The calibration coefficients were then applied to the acquired images, comparing the EPID dose images with films. Measurements were performed with open field, placing the film at the level of the EPID. The standard deviation of the distribution of the point-to-point difference is 0.6%. An approach of this type for the EPID calibration has many advantages with respect to the standard methods - it does not need an external dosimeter, it is not related to the irradiation techniques, and it is easy to implement in the clinical practice. Moreover, it can be applied in case of transit or nontransit dosimetry, solving the problem of the EPID calibration independently from the dose reconstruction method.

The effects on pain and activity of daily living caused by crusted exudation in patients with head and neck cancer treated with cetuximab and radiotherapy.

PURPOSE: To date, the specific role of "in-field" crusting exudation on pain and on activity of daily living (ADL) in head and neck cancer (HNSCC) patients undergoing treatment with cetuximab and radiochemotherapy has been neglected. The purpose of the study was to evaluate the role of crusting exudation on the severity of pain and ADL METHODS: Thirty-seven of the 45 HNSCC patients enrolled in the alternating radiotherapy, chemotherapy, and cetuximab trial were evaluated in this study. The main radiodermatitis signs (the intensity of erythema, the extension of dry, and moist desquamation and of necrosis)--including crusting exudation severity--pain, ADL, and radiodermatitis scores were registered at least weekly during and after treatment. The correlation between crusting exudation and pain or ADL was evaluated. RESULTS: The "in-field" crusting exudation score seemed to have the strongest correlation with pain (Spearman's rho = 0.897; p < 0.001) and the most intense influence on it (Co-B = 0.715; 95% C.I. = 0.643-0.787). However, it seemed to have a weaker correlation with ADL than the other clinical radiodermatitis signs. CONCLUSIONS: Crusts have the strongest correlation with pain in patients with Cetuximab-related radiation dermatitis. Moreover, the presence of crusts can lead operators to misclassify dermatitis as score 4, causing unnecessary delays or interruptions in treatment.

The cisplatin-irradiation combination suggests that apoptosis is not a major determinant of clonogenic death.

It is commonly believed that tumor cells treated with anticancer agents, chemotherapy and/or radiation, die by apoptosis and that tumors which do not undergo apoptosis are resistant to treatment. In this study, we investigated the molecular basis underlying cisplatin cytotoxicity in the murine teratocarcinoma F9 cell line to see whether irradiation enhances cisplatin-induced cytotoxicity. We compared the apoptosis induced by chemo and/or radiotherapy with other cellular effects such as cell survival, clonogenic capability, cell cycle perturbation, expression of p53 and p53-related mRNAs, and necrosis. When combined with radiation, a clear additive cytotoxic effect of cisplatin was demonstrated. We found that both cisplatin and radiation induced cell death, but the level of induced apoptosis was low and there was no correlation with the results of the clonogenic assays: we noted a difference between cytotoxic effects in the clonogenic assay and the extent of apoptosis by fluorescence-activated cell sorter analysis, suggesting that cell killing reflected not only apoptosis but also cell cycle arrest, and that apoptosis, cell kinetics and clonogenicity suppression were independent processes.

Clinical use of EBT model Gafchromic film in radiotherapy.

The Gafchromic EBT was recently introduced in film dosimetry for external beam therapy (EBT). The high spatial resolution, weak energy dependence, and near-tissue equivalence of EBT films make them suitable for measurement of dose distributions in radiotherapy, especially intensity-modulated radiation therapy (IMRT). Starting with a sensitometric curve and dose uncertainty relative to the flatbed scanner, the goal of this study was to find an efficient method of correcting for light scattering, and to compare dose distribution supplied by Gafchromic EBT with the distribution obtained with a 2D ion-chamber detector system. Light scattering was analyzed for different levels of dose, and was found to depend on the red-scale value as well as the position of the pixel on the scanner. Many "uniform" films were exposed at different levels of dose to create a two-dimensional matrix correction to take this effect into account. The dose distribution obtained for three clinical beams (10 x 10, 15 x 15 cm open fields and 12 x 12 cm wedge 60 degrees field) were in agreement with those supplied by the 2D array. Gamma index <1 (using 5 mm distance and 5% dose as constraints) for the three fields considered was reached in an average of 98% of the points.