A cost-effectiveness analysis of an integrated clinical-radiogenomic screening program for the identification of BRCA 1/2 carriers (e-PROBE study).

Current approach to identify BRCA 1/2 carriers in the general population is ineffective as most of the carriers remain undiagnosed. Radiomics is an emerging tool for large scale quantitative analysis of features from standard diagnostic imaging and has been applied also to identify gene mutational status. The objective of this study was to evaluate the clinical and economic impact of integrating a radiogenomics model with clinical and family history data in identifying BRCA mutation carriers in the general population. This cost-effective analysis compares three different approaches to women selection for BRCA testing: established clinical criteria/family history (model 1); established clinical criteria/family history and the currently available radiogenomic model (49% sensitivity and 87% specificity) based on ultrasound images (model 2); same approach used in model 2 but simulating an improvement of the performances of the radiogenomic model (80% sensitivity and 95% specificity) (model 3). All models were trained with literature data. Direct costs were calculated according to the rates currently used in Italy. The analysis was performed simulating different scenarios on the generation of 18-year-old girls in Italy (274,000 people). The main outcome was to identify the most effective model comparing the number of years of BRCA-cancer healthy life expectancy (HLYs). An incremental cost-effectiveness ratio (ICER) was also derived to determine the cost in order to increase BRCA carriers-healthy life span by 1 year. Compared to model 1, model 2 increases the detection rate of BRCA carriers by 41.8%, reduces the rate of BRCA-related cancers by 23.7%, generating over a 62-year observation period a cost increase by 2.51 €/Year/Person. Moreover, model 3 further increases BRCA carriers detection (+ 68.3%) and decrease in BRCA-related cancers (- 38.4%) is observed compared to model 1. Model 3 increases costs by 0.7 €/Year/Person. After one generation, the estimated ICER in the general population amounts to about 3800€ and 653€ in model 2 and model 3 respectively. Model 2 has a massive effect after only one generation in detecting carriers in the general population with only a small cost increment. The clinical impact is limited mainly due to the current low acceptance rate of risk-reducing surgeries. Further multicentric studies are required before implementing the integrated clinical-radiogenomic model in clinical practice.

Transoral versus transfacial surgical approach to maxillary tumors: evaluation of outcomes and perspectives.

Neoplasms of the maxilla have multiple different origins and histology, and often extend towards the infratemporal fossa, orbit, or skull base. Extensive resection may be required, often leading to poor esthetic and functional results. Usually, these lesions are removed via a transfacial approach. The aim of this study was to compare the outcomes of the transoral versus transfacial approach for maxillary tumors. A single-institution retrospective study was conducted on patients with maxillary-midface tumors, treated between January 2009 and December 2019. The patients were divided into two groups according to the surgical approach, transfacial or transoral, and the following outcomes were assessed: extent of the resection based on Brown's classification; postoperative pathology margin assessment; reconstruction technique; esthetic/functional results. A total of 178 patients were included. A satisfactory resection was obtained in both groups, with the transoral cohort achieving a higher rate of clear oncological margins (positive margins: transoral group 3.7% versus transfacial group 6.8%, P = 0.389) and a significantly higher University of Washington Quality of Life score (mean 72.2 versus 67.8, P < 0.001). Even large and invasive tumors can be treated successfully with the transoral approach, avoiding unesthetic facial scars while still providing complete resection of the tumor.

The 2022 Assisi Think Tank Meeting: White paper on optimising radiation therapy for breast cancer.

The present white paper, referring to the 4th Assisi Think Tank Meeting on breast cancer, reviews state-of-the-art data, on-going studies and research proposals. <70% agreement in an online questionnaire identified the following clinical challenges: 1: Nodal RT in patients who have a) 1-2 positive sentinel nodes without ALND (axillary lymph node dissection); b) cN1 disease transformed into ypN0 by primary systemic therapy and c) 1-3 positive nodes after mastectomy and ALND. 2. The optimal combination of RT and immunotherapy (IT), patient selection, IT-RT timing, and RT optimal dose, fractionation and target volume. Most experts agreed that RT- IT combination does not enhance toxicity. 3: Re-irradiation for local relapse converged on the use of partial breast irradiation after second breast conserving surgery. Hyperthermia aroused support but is not widely available. Further studies are required to finetune best practice, especially given the increasing use of re-irradiation.

Multiparametric imaging guided HDR interventional radiotherapy (brachytherapy) boost in localized prostate cancer: a multidisciplinary experience.

OBJECTIVE: The aim of this study was to report a monoinstitutional multidisciplinary experience about the use of multiparametric imaging to identify the areas with higher risk of relapse in localized prostate cancer, with the purpose of allowing a biologically planned target dose escalation. PATIENTS AND METHODS: We performed a retrospective evaluation of patients diagnosed with prostate cancer who received treatments at our Interventional Oncology Center with interstitial interventional radiotherapy from 2014 to 2022. Inclusion criteria were histologically confirmed localized prostate cancer; and National Comprehensive Cancer Network (NCCN) risk class unfavorable intermediate or high/very high risk. The diagnostic work-up included multiparametric Magnetic resonance imaging (MRI), multiparametric Transrectal ultrasound (TRUS), Positron Emission Tomography Computed Tomography (PET-CT) with choline or PSMA (or alternatively bone scan). All patients were assessed and received one treatment with interstitial high-dose-rate interventional radiotherapy (brachytherapy) delivering external beam radiotherapy (46 Gy). All procedures were performed using transrectal ultrasound guidance under general anesthesia and the prescribed doses were 10 Gy to the whole prostate, 12 Gy to the peripheral zone and 15 Gy to the areas at risk. RESULTS: We report the data of 21 patients who were considered for the statistical analysis with a mean age of 62.5 years. The mean PSA nadir was 0.03 ng/ml (range 0-0.09). So far, no biochemical nor radiological recurrences have been recorded in our series. Regarding acute toxicity, the most commonly reported side effects were G1 urinary in 28.5% of patients and G2 urinary in 9.5%; all recorded acute toxicities resolved spontaneously. CONCLUSIONS: We present a real-life experience of biologically planned local dose escalation by interventional radiotherapy (brachytherapy) boost, followed by external beam radiotherapy in patients with intermediate unfavorable- or high/very high risk. The local control and the biochemical control rates are proved to be excellent and the toxicity profile tolerable.

MRI-derived radiomics to guide post-operative management of glioblastoma: Implication for personalized radiation treatment volume delineation.

Background: The glioblastoma's bad prognosis is primarily due to intra-tumor heterogeneity, demonstrated from several studies that collected molecular biology, cytogenetic data and more recently radiomic features for a better prognostic stratification. The GLIFA project (GLIoblastoma Feature Analysis) is a multicentric project planned to investigate the role of radiomic analysis in GB management, to verify if radiomic features in the tissue around the resection cavity may guide the radiation target volume delineation. Materials and methods: We retrospectively analyze from three centers radiomic features extracted from 90 patients with total or near total resection, who completed the standard adjuvant treatment and for whom we had post-operative images available for features extraction. The Manual segmentation was performed on post gadolinium T1w MRI sequence by 2 radiation oncologists and reviewed by a neuroradiologist, both with at least 10 years of experience. The Regions of interest (ROI) considered for the analysis were: the surgical cavity ± post-surgical residual mass (CTV_cavity); the CTV a margin of 1.5 cm added to CTV_cavity and the volume resulting from subtracting the CTV_cavity from the CTV was defined as CTV_Ring. Radiomic analysis and modeling were conducted in RStudio. Z-score normalization was applied to each radiomic feature. A radiomic model was generated using features extracted from the Ring to perform a binary classification and predict the PFS at 6 months. A 3-fold cross-validation repeated five times was implemented for internal validation of the model. Results: Two-hundred and seventy ROIs were contoured. The proposed radiomic model was given by the best fitting logistic regression model, and included the following 3 features: F_cm_merged.contrast, F_cm_merged.info.corr.2, F_rlm_merged.rlnu. A good agreement between model predicted probabilities and observed outcome probabilities was obtained (p-value of 0.49 by Hosmer and Lemeshow statistical test). The ROC curve of the model reported an AUC of 0.78 (95% CI: 0.68-0.88). Conclusion: This is the first hypothesis-generating study which applies a radiomic analysis focusing on healthy tissue ring around the surgical cavity on post-operative MRI. This study provides a preliminary model for a decision support tool for a customization of the radiation target volume in GB patients in order to achieve a margin reduction strategy.

Volumetric Intensity-Modulated Arc Stereotactic Radiosurgery Boost in Oligometastatic Patients with Spine Metastases: a Dose-escalation Study.

AIMS: To report the final results of a dose-escalation study of volumetric intensity-modulated arc stereotactic radiosurgery (VMAT-SRS) boost after three-dimensional conformal radiation therapy in patients with spine metastases. MATERIALS AND METHODS: Oligometastatic cancer patients bearing up to five synchronous metastases (visceral or bone, including vertebral ones) and candidates for surgery or radiosurgery were considered for inclusion. 25 Gy was delivered in 10 daily fractions (2 weeks) to the metastatic lesion, affected vertebrae and adjacent ones (one cranial and one caudal vertebra). Sequentially, the dose to spinal metastases was progressively increased (8 Gy, 10 Gy, 12 Gy) in the patient cohorts. Dose-limiting toxicities were defined as any treatment-related non-hematologic acute adverse effects rated as grade ≥3 or any acute haematological toxicity rated as ≥ 4 by the Radiation Therapy Oncology Group scale. RESULTS: Fifty-two lesions accounting for 40 consecutive patients (male/female: 29/11; median age: 71 years; range 40-85) were treated from April 2011 to September 2020. Most patients had a primary prostate (65.0%) or breast cancer (22.5%). Thirty-two patients received 8 Gy VMAT-SRS boost (total BED α/ß10: 45.6 Gy), 14 patients received 10 Gy (total BED α/ß10: 51.2 Gy) and six patients received 12 Gy (total BED α/ß10: 57.6 Gy). The median follow-up time was over 70 months (range 2-240 months). No acute toxicities > grade 2 and no late toxicities > grade 1 were recorded. The overall response rate based on computed tomography/positron emission tomography-computed tomography/magnetic resonance was 78.8%. The 24-month actuarial local control, distant metastases-free survival and overall survival rates were 88.5%, 27.1% and 90.3%, respectively. CONCLUSION: A 12 Gy spine metastasis SRS boost following 25 Gy to the affected and adjacent vertebrae was feasible with an excellent local control rate and toxicity profile.

Contrasting opioid use for pain management in microvascular head and neck reconstruction: an international study.

Opioids are often the mainstay of postoperative pain management, despite strong evidence of their ill effects and potential for long-term addiction. The goal of this study was to quantify opioid use and contrast pain management strategies of multiple international institutions performing fibula free flap reconstruction. A retrospective multicenter cohort study was designed, including five international centers. For inclusion, the patients had to have undergone a primary fibula free flap reconstruction of the mandible. A total of 185 patients were included. The median opioid use across all centers at 72 hours was 133 oral morphine equivalents. The highest utilization was in the USA (P < 0.001), which was approximately six times that of Italy, four times that of Argentina, and twice that of India, despite all centers performing a similar procedure. Based on this study there are clear differences in prescribing practices and ideologies among surgeons from different countries.

Project for interventional Oncology LArge-database in liveR Hepatocellular carcinoma - Preliminary CT-based radiomic analysis (POLAR Liver 1.1).

OBJECTIVE: The objective of this study is to find a contrast-enhanced CT-radiomic signature to predict clinical incomplete response in patients affected by hepatocellular carcinoma who underwent locoregional treatments. PATIENTS AND METHODS: 190 patients affected by hepatocellular carcinoma treated using focal therapies (radiofrequency or microwave ablation) from September 2018 to October 2020 were retrospectively enrolled. Treatment response was evaluated on a per-target-nodule basis on the 6-months follow-up contrast-enhanced CT or MR imaging using the mRECIST criteria. Radiomics analysis was performed using an in-house developed open-source R library. Wilcoxon-Mann-Whitney test was applied for univariate analysis; features with a p-value lower than 0.05 were selected. Pearson correlation was applied to discard highly correlated features (cut-off=0.9). The remaining features were included in a logistic regression model and receiver operating characteristic curves; sensitivity, specificity, positive and negative predictive value were also computed. The model was validated performing 2000 bootstrap resampling. RESULTS: 56 treated lesions from 42 patients were selected. Treatment responses were: complete response for 26 lesions (46.4%), 18 partial responses (32.1%), 10 stable diseases (17.9%), 2 progression diseases (3.6%). Area-Under-Curve value was 0.667 (95% CI: 0.527-0.806); accuracy, sensitivity, specificity, positive and negative predictive values were respectively 0.66, 0.85, 0.50, 0.59 and 0.79. CONCLUSIONS: This contrast-enhanced CT-based model can be helpful to early identify poor responder's hepatocellular carcinoma patients and personalize treatments.

Stereotactic radiosurgery for bone metastases in oligometastatic prostate cancer patients: DESTROY-2 clinical trial subanalysis.

INTRODUCTION: Aim of this analysis was to report toxicity and clinical outcomes in oligorecurrent prostate cancer (PCa) patients treated with single fraction stereotactic radiosurgery (SRS) for bone metastases. METHODS: We separately analyzed clinical data of PCa patients with bone oligometastases enrolled in a prospective phase I trial (DESTROY-2). DESTROY-2 was based on SRS delivered using volumetric modulated arc therapy in patients with primary or metastatic tumors in several extra-cranial body sites. Acute and late toxicity, biochemical tumor response, local control (LC), distant metastases-free (DPFS), progression-free (PFS), time to next-line systemic treatment-free (NEST-FS), and overall survival (OS) were calculated. RESULTS: Data on 37 PCa patients, carrying out 50 bone metastases, candidates for curative-intent treatment and treated with SRS at our Institution were collected. SRS dose ranged between 12 and 24 Gy. One grade 1 acute skin toxicity in one patient treated on the hip (24 Gy) and one grade 1 late skin toxicity in a patient with a scapular lesion (24 Gy) were recorded. No cases of bone fracture were registered in the treated population. With a median follow-up of 25 months (range 3-72 months) 2-year actuarial LC, DPFS, PFS, and OS were 96.7%, 58.1%, 58.1%, and 95.8%, respectively. Median and 2-year NEST-FS were 30 months (range 1-69 months) and 51.2%, respectively. CONCLUSIONS: Data analysis showed few toxicity events, high local control rate and prolonged NEST-FS after linear accelerator-based radiosurgery of bone oligometastases from PCa. The possibility of postponing systemic treatments in patients with oligometastatic PCa by means of SRS should be taken into account. Further prospective studies on larger series are needed to confirm the reported results.

A multicenter LArge retrospectIve daTabase on the personalization of stereotactic ABlative radiotherapy use in lung metastases from colon-rectal cancer: The LaIT-SABR study.

INTRODUCTION: Stereotactic ablative radiotherapy (SABR) has been shown to increase survival in oligometastatic disease, but local control of colorectal metastases remains poor. We aimed to identify potential predictive factors of SBRT response through a multicenter large retrospective database and to investigate the progression to the polymetastatic disease (PMD). MATERIAL AND METHODS: The study involved 23 centers, and was approved by the Ethical Committee (Prot. Negrar 2019-ZT). 1033 lung metastases were reported. Clinical and biological parameters were evaluated as predictive for freedom from local progression-free survival (FLP). Secondary end-point was the time to the polymetastatic conversion (tPMC). RESULTS: Two-year FLP was 75.4%. Two-year FLP for lesions treated with a BED < 00 Gy, 100-124 Gy, and ≥125 Gy was 76.1%, 70.6%, and 94% (p = 0.000). Two-year FLP for lesion measuring ≤10 mm, 10-20 mm, and >20 mm was 79.7%, 77.1%, and 66.6% (p = 0.027). At the multivariate analysis a BED ≥125 Gy significantly reduced the risk of local progression (HR 0.24, 95%CI 0.11-0.51; p = 0.000). Median tPMC was 26.8 months. Lesions treated with BED ≥125 Gy reported a significantly longer tPMC as compared to lower BED. The median tPMC for patients treated to 1, 2-3 or 4-5 simultaneous oligometastases was 28.5, 25.4, and 9.8 months (p = 0.035). CONCLUSION: The present is the largest series of lung colorectal metastases treated with SABR. The results support the use of SBRT in lung oligometastatic colorectal cancer patients as it might delay the transition to PMD or offer relatively long disease-free period in selected cases. Predictive factors were identified for treatment personalization.

When your MR linac is down: Can an automated pipeline bail you out of trouble?

PURPOSE: The unique treatment delivery technique provided by magnetic resonance guided radiotherapy (MRgRT) can represent a significant drawback when system fail occurs. This retrospective study proposes and evaluates a pipeline to completely automate the workflow necessary to shift a MRgRT treatment to a traditional radiotherapy linac. MATERIAL AND METHODS: Patients undergoing treatment during the last MRgRT system failure were retrospectively included in this study. The core of the proposed pipeline was based on a tool able to mimic the original MR linac dose distribution. The so obtained dose distribution (AUTO) has been compared with the distribution obtained in the conventional radiotherapy linac (MAN). Plan comparison has been performed in terms of time required to obtain the final dose distribution, DVH parameters, dosimetric indices and visual analogue scales scoring by radiation oncologists. RESULTS: AUTO plans generation has been obtained within 10 min for all the considered cases. All AUTO plans were found to be within clinical tolerance, showing a mean target coverage variation of 1.7% with a maximum value of 4.3% and a minimum of 0.6% when compared with MAN plans. The highest OARs mean variation has been found for rectum V60 (6.7%). Dosimetric indices showed no relevant differences, with smaller gradient measure in favour of AUTO plans. Visual analogue scales scoring has confirmed comparable plan quality for AUTO plans. CONCLUSION: The proposed workflow allows a fast and accurate generation of automatic treatment plans. AUTO plans can be considered equivalent to MAN ones, with limited clinical impact in the worst-case scenario.

Stereotactic body radiotherapy to lymph nodes in oligoprogressive castration-resistant prostate cancer patients: a post hoc analysis from two phase I clinical trials.

The prognosis of prostate cancer (PC) is generally favorable but the incidence of metastases is relatively high after the treatment of the primary tumor, especially in high-risk patients. Fractionated stereotactic body radiotherapy (SBRT) or single fraction stereotactic body radiosurgery (SRS) are emerging treatment options in this setting. However, data on SBRT/SRS in patients with metastatic castration-resistant PC (mCRPC) are largely lacking, particularly in subjects with nodal lesions. Therefore, we evaluated outcomes and toxicity recorded in mCRPC patients with nodal oligoprogression. Patients included in this analysis had ≤ 5 metastatic sites without visceral lesions and underwent SBRT/SRS on nodal metastases. Thirty-eight patients carrying out 61 nodal metastases were analyzed. The median SRS dose was 20 Gy (range 12-24 Gy) and the most common schedule was 20 Gy (44.8%). The median SBRT dose was 45 Gy (range 20-50 Gy) and the most common regimen was 45 Gy in 5 fractions (37.9%). Thirty-seven patients (97.4%) showed only grade 0-1 acute toxicity while one patient reported grade 2 dysphagia. In terms of late toxicity, one grade 2 laryngeal, one grade 1 skin and one grade 1 gastrointestinal toxicities were recorded. Two-year actuarial local control (LC), distant progression-free survival, progression-free survival (PFS) and overall survival were 94.0, 47.2, 47.2, and 90.2%, respectively. Two-year next line systemic therapy-free survival (NEST-FS) was 67.7%. In conclusion, the efficacy in terms of LC of SBRT/SRS in patients with nodal metastases from PC was confirmed. Moreover, this analysis suggests the efficacy in terms of PFS and NEST-FS also in the setting of oligoprogressive PC. In fact, about one-third of patients were free from progressive disease and two-third of subjects did not require hormonal therapy switch or discontinuation three years after treatment.

On dose cube pixel spacing pre-processing for features extraction stability in dosiomic studies.

PURPOSE: Dosiomics allows to parameterize regions of interest (ROIs) and to produce quantitative dose features encoding the spatial and statistical distribution of radiotherapy dose. The stability of dosiomics features extraction on dose cube pixel spacing variation has been investigated in this study. MATERIAL AND METHODS: Based on 17 clinical delivered dose distributions (Pn), dataset has been generated considering all the possible combinations of four dose grid resolutions and two calculation algorithms. Each dose voxel cube has been post-processed considering 4 different dose cube pixel spacing values: 1x1x1, 2x2x2, 3x3x3 mm3 and the one equal to the planning CT. Dosiomics features extraction has been performed from four different ROIs. The stability of each extracted dosiomic feature has been analyzed in terms of coefficient of variation (CV) intraclass correlation coefficient (ICC). RESULTS: The highest CV mean values were observed for PTV ROI and for the grey level size zone matrix features family. On the other hand, the lowest CV mean values have been found for RING ROI for the grey level co-occurrence matrix features family. P3 showed the highest percentage of CV >1 (1.14%) followed by P15 (0.41%), P1 (0.29%) and P13 (0.19%). ICC analysis leads to identify features with an ICC >0.95 that could be considered stable to use in dosiomic studies when different dose cube pixel spacing are considered, especially the features in common among the seventeen plans. CONCLUSION: Considering the observed variability, dosiomic studies should always provide a report not only on grid resolution and algorithm dose calculation, but also on dose cube pixel spacing.

Prevalence of nodal involvement in rectal cancer after chemoradiotherapy.

BACKGROUND: The purpose of this study was to investigate the prevalence of ypN+ status according to ypT category in patients with locally advanced rectal cancer treated with chemoradiotherapy and total mesorectal excision, and to assess the impact of ypN+ on disease recurrence and survival by pooled analysis of individual-patient data. METHODS: Individual-patient data from 10 studies of chemoradiotherapy for rectal cancer were included. Pooled rates of ypN+ disease were calculated with 95 per cent confidence interval for each ypT category. Kaplan-Meier and Cox regression analyses were undertaken to assess influence of ypN status on 5-year disease-free survival (DFS) and overall survival (OS). RESULTS: Data on 1898 patients were included in the study. Median follow-up was 50 (range 0-219) months. The pooled rate of ypN+ disease was 7 per cent for ypT0, 12 per cent for ypT1, 17 per cent for ypT2, 40 per cent for ypT3, and 46 per cent for ypT4 tumours. Patients with ypN+ disease had lower 5-year DFS and OS (46.2 and 63.4 per cent respectively) than patients with ypN0 tumours (74.5 and 83.2 per cent) (P < 0.001). Cox regression analyses showed ypN+ status to be an independent predictor of recurrence and death. CONCLUSION: Risk of nodal metastases (ypN+) after chemoradiotherapy increases with advancing ypT category and needs to be considered if an organ-preserving strategy is contemplated.

When patients are diagnosed with rectal cancer and the tumour grows beyond the rectal wall there is a high risk that the tumour has spread to nearby lymph nodes. This study showed that this relationship between tumour invasion depth and lymph node involvement is similar after treatment with (chemo)radiotherapy. Patients who have tumour cells remaining in the lymph nodes after (chemo) radiotherapy have a worse prognosis than patients who do not have cancer cells remaining in the lymph nodes. When an organ-preserving treatment is considered as an alternative therapy, this should be kept in mind during patient counselling.

VMAT-like plans for magnetic resonance guided radiotherapy: Addressing unmet needs.

PURPOSE: VMAT delivery technique is currently not applicable to Magnetic Resonance-guided radiotherapy (MRgRT) hybrid systems. Aim of this study is to evaluate an innovative VMAT-like (VML) delivery technique. MATERIAL AND METHODS: First, planning and dosimetric evaluation of the MRgRT VML treatment have been performed on 10 different disease sites and the results have been compared with the corresponding IMRT plans. Then, in the second phase, 10 of the most dosimetrically challenging locally advanced pancreas treatment plans have been retrospectively re-planned using the VML approach to explore the potentiality of this new delivery technique. Finally, VML robustness was evaluated and compared with the IMRT plans, considering a lateral positioning error of ± 5 mm. RESULTS: In phase one, all VML plans were within constraint for all OARs. When PTV coverage is considered, in the 50% of the cases VML PTV coverage is equal or higher than in IMRT plan. In the remaining 50%, the highest target under coverage difference in comparison with IMRT plan is -1.71%. The mean and maximum treatment time differences (VML-IMRT) is 0.2 min and 3.1 min respectively. In phase two, the treatment time variation (VML-IMRT), shows a mean, maximum and minimum variations of 1.3, 4.6 and -0.6 min respectively. All VML plans have a better target coverage if compared with IMRT plans, keeping in any case the OARs constraints within tolerance. VML doesn't increase plan robustness. CONCLUSION: VMAT-like treatment approach appeared to be an efficient planning solution and it was decided to clinically implement it in daily practice, especially in the frame of hypo fractionated treatments.

Dosimetric accuracy of dual isocenter irradiation in low magnetic field resonance guided radiotherapy system for extended abdominal tumours.

PURPOSE: Due to limited field size of Magnetic Resonance Linear Accelerators (MR-Linac), some treatments could require a dual-isocenter planning approach to achieve a complete target coverage and thus exploit the benefits of the online adaptation. This study evaluates the dosimetric accuracy of the dual-isocenter intensity modulated radiation therapy (IMRT) delivery technique for MR-Linac. MATERIAL AND METHODS: Dual-isocenter multi leaf collimator (MLC) and couch accuracy tests have been performed to evaluate the delivery accuracy of the system. A mono-isocenter plan delivered in clinical practice has then been retrospectively re-planned with dual-isocenter technique. The dual-isocenter plan has been re-calculated and delivered on a 3-dimensional (3D) ArcCHECK phantom and 2-dimensional (2D) films to assess its dosimetric accuracy in terms of gamma analysis. Clinical and planning target volume (CTV and PTV respectively) coverage robustness was then investigated after the introduction of ± 2 mm and ± 5 mm positioning errors by shifting the couch. RESULTS: MLC and couch accuracy tests confirmed the system accuracy in delivering a dual-isocenter irradiation. 2D/3D gamma analysis results occurred always to be above 95% if considered a gamma criteria 1%/2 mm and 1%/1 mm respectively for the 2D and 3D analysis. The mean variations for CTV D98% and PTV V95% were 0.2% and 1.1% respectively when positioning error was introduced separately in each direction, while the maximum observed variations were 0.9% (CTV) and 3.7% (PTV). CONCLUSION: The dosimetric accuracy of dual-isocenter irradiation has been verified for MR-Linac, achieving accurate and robust treatment strategy and improving dose conformality also in presence of targets whose extension exceeds the nominal maximum field size.

Process mining to optimize palliative patient flow in a high-volume radiotherapy department.

INTRODUCTION: In radiotherapy, palliative patients are often suboptimal managed and patients experience long waiting times. Event-logs (recorded local files) of palliative patients, could provide a continuative decision-making system by means of shared guidelines to improve patient flow. Based on an event-log analysis, we aimed to accurately understand how to successively optimize patient flow in palliative care. METHODS: A process mining methodology was applied on palliative patient flow in a high-volume radiotherapy department. Five hundred palliative radiation treatment plans of patients with bone and brain metastases were included in the study, corresponding to 290 patients treated in our department in 2018. Event-logs and the relative attributes were extracted and organized. A process discovery algorithm was applied to describe the real process model, which produced the event-log. Finally, conformance checking was performed to analyze how the acquired event-log database works in a predefined theoretical process model. RESULTS: Based on the process discovery algorithm, 53 (10%) plans had a dose prescription of 8 Gy, 249 (49.8%) plans had a dose prescription of 20 Gy and 159 (31.8%) plans had a dose prescription of 30 Gy. The remaining 39 (7.8%) plans had different dose prescriptions. Considering a median value, conformance checking demonstrated that event-logs work in the theoretical model. CONCLUSIONS: The obtained results partially validate and support the palliative patient care guideline implemented in our department. Process mining can be used to provide new insights, which facilitate the improvement of existing palliative patient care flows.

Preoperative chemoradiotherapy affects postoperative outcomes and functional results in patients treated with transanal endoscopic microsurgery for rectal neoplasms.

BACKGROUND: The aim of this study was to quantify the incidence of short-term postoperative complications and functional disorders at 1 year from transanal endoscopic microsurgery (TEM) for rectal neoplasms, to compare patients treated with TEM alone and with TEM after preoperative chemoradiotherapy (CRT) and to analyse factors influencing postoperative morbidity and functional outcomes. METHODS: A retrospective study was conducted on all patients treated with TEM for rectal neoplasms at our institution in January 2000-December 2017. Data from a prospectively maintained database were retrospectively analysed. Patients were divided into two groups: adenoma or early rectal cancer (no CRT group) and locally advanced extraperitoneal rectal cancer with major or complete clinical response after preoperative CRT (CRT group). Short-term postoperative mortality and morbidity and the functional results at 1 year were recorded. The two groups were compared, and a statistical analysis of factors influencing postoperative morbidity and functional outcomes was performed. Functional outcome was also evaluated with the low anterior resection syndrome (LARS) score (0-20 no LARS, 21-29 minor LARS and 30-42 major LARS). RESULTS: One hundred and thirteen patients (71 males, 42 females, median age 64 years [range 41-80 years]) were included in the study (46 in the CRT group). The overall postoperative complication rate was 23.0%, lower in the noCRT group (p < 0.001), but only 2.7% were grade ≥ 3. The most frequent complication was suture dehiscence (17.6%), which occurred less frequently in the noCRT group (p < 0.001). At 1 year from TEM, the most frequent symptoms was urgency (11.9%, without significant differences between the CRT group and the noCRT group); the noCRT group experienced a lower rate of soiling than the CRT group (0% vs. 7.7%; p: 0.027). The incidence of LARS was evaluated in 47 patients from May 2012 on and was 21.3% occurring less frequently in the noCRT group (10% vs. 41.2%; p: 0.012). Only 6.4% of the patients evaluated experienced major LARS. In multivariate analysis, preoperative CRT significantly worsened postoperative morbidity and functional outcomes. CONCLUSIONS: TEM is a safe procedure associated with only low risk of severe postoperative complications and major LARS. Preoperative CRT seems to increase the rate of postoperative morbidity after TEM and led to worse functional outcomes at 1 year after surgery.