Basics and frontiers on pancreatic cancer for radiation oncology: Target delineation, SBRT, SIB technique, MRgRT, particle therapy, immunotherapy and clinical guidelines

Pancreatic cancer represents a modern oncological urgency. Its management is aimed to both distal and local disease control. Resectability is the cornerstone of treatment aim. It influences the clinical presentation\u2019s definitions as up-front resectable, borderline resectable and locally advanced (unresectable). The main treatment categories are neoadjuvant (preoperative), definitive and adjuvant (postoperative). This review will focus on i) the current indications by the available national and international guidelines; ii) the current standard indications for target volume delineation in radiotherapy (RT); iii) the emerging modern technologies (including particle therapy and Magnetic Resonance [MR]-guided-RT); iv) stereotactic body radiotherapy (SBRT), as the most promising technical delivery application of RT in this framework; v) a particularly promising dose delivery technique called simultaneous integrated boost (SIB); and vi) a multimodal integration opportunity: the combination of RT with immunotherapy

Basics and frontiers on pancreatic cancer for radiation oncology: Target delineation, SBRT, SIB technique, MRgRT, particle therapy, immunotherapy and clinical guidelines

Pancreatic cancer represents a modern oncological urgency. Its management is aimed to both distal and local disease control. Resectability is the cornerstone of treatment aim. It influences the clinical presentation’s definitions as up-front resectable, borderline resectable and locally advanced (unresectable). The main treatment categories are neoadjuvant (preoperative), definitive and adjuvant (postoperative). This review will focus on i) the current indications by the available national and international guidelines; ii) the current standard indications for target volume delineation in radiotherapy (RT); iii) the emerging modern technologies (including particle therapy and Magnetic Resonance [MR]-guided-RT); iv) stereotactic body radiotherapy (SBRT), as the most promising technical delivery application of RT in this framework; v) a particularly promising dose delivery technique called simultaneous integrated boost (SIB); and vi) a multimodal integration opportunity: the combination of RT with immunotherapy

Predictive and prognostic value of inflammatory markers in locally advanced rectal cancer (PILLAR) – A multicentric analysis by the Italian Association of Radiotherapy and Clinical Oncology (AIRO) Gastrointestinal Study Group

Background: Patients (pts) affected with locally advanced rectal cancer (LARC) may respond differently to neoadjuvant chemoradiotherapy (nCRT). The identification of reliable biomarkers able to predict oncological outcomes could help in the development of risk-adapted treatment strategies. It has been suggested that inflammation parameters may have a role in predicting tumor response to nCRT and survival outcomes and in rectal cancer, but no definitive conclusion can be drawn at present. The aim of the current study is to evaluate the role of baseline inflammatory markers as prognostic and predictive factors in a large multicentric Italian cohort of LARC pts. Methods: Patients diagnosed with LARC from January 2002 to December 2019 in 9 Italian centers were retrospectively collected. Patients underwent long-course RT with chemotherapy based on fluoropyrimidine ± oxaliplatin followed by surgery. Inflammatory markers were retrieved based on a pre-treatment blood sample including HEI (hemo-eosinophils inflammation index), SII (systemic index of inflammation), NLR (neutrophil-to-lymphocyte ratio), PLR (platelet-to-lymphocyte ratio) and MLR (monocyte-to-lymphocyte ratio). Outcomes of interest were pathological complete response (pCR), disease-free survival (DFS), and overall survival (OS). Results: 808 pts were analyzed. pCR rate was 22 %, 5yOS and 5yDFS were 84.0% and 63.1% respectively. Multivariate analysis identified that a NLR cut-off value >1.2 and SII cut-off value >500 could predict pCR (p = 0.05 and 0.009 respectively). In addition to age, extramesorectal nodes and RT dose, MLR >0.18 (p = 0.03) and HEI = 3 (p = 0.05) were independent prognostic factors for DFS. Finally, age, RT dose, MLR with a cut-off >0.35 (p = 0.028) and HEI = 3 (p = 0.045) were independent predictors of OS. Conclusions: Higher values of baseline composite inflammatory markers can serve as predictors of lower pCR rates and worse survival outcomes in LARC patients undergoing nCRT. More reliable data from prospective studies could lead to the integration of these inexpensive and easy-to-derive tools into clinical practice

Contouring of emerging organs-at-risk (OARS) of the female pelvis and interobserver variability. A study by the Italian association of radiotherapy and clinical oncology (AIRO)

Purpose: To provide straightforward instructions for daily practice in delineating emerging organs-at-risk (OARs) of the female pelvis and to discuss the interobserver variability in a two-step multicenter study.Methods and materials: A contouring atlas with anatomical boundaries for each emerging OAR was realized by radiation oncologists and radiologists who are experts in pelvic imaging, as per their knowledge and clinical practice. These contours were identified as quality benchmarks for the analysis subsequently carried out. Radiation oncologists not involved in setting the custom-built contouring atlas and interested in the treatment of gynecological cancer were invited to participate in this 2-step trial. In the first step all participants were supplied with a selected clinical case of locally advanced cervical cancer and had to identify emerging OARs (Levator ani muscle; Puborectalis muscle; Internal anal sphincter; External anal sphincter; Bladder base and trigone; Bladder neck; Iliac Bone Marrow; Lower Pelvis Bone Marrow; Lumbosacral Bone Marrow) based on their own personal knowledge of pelvic anatomy and experience. The suggested OARs and the contouring process were then presented at a subsequent webinar meeting with a contouring laboratory. Finally, in the second step, after the webinar meeting, each participant who had joined the study but was not involved in setting the benchmark received the custom-built contouring atlas with anatomical boundaries and was requested to delineate again the OARs using the tool provided. The Dice Similarity Coefficient (DSC) and the Jaccard Similarity Coefficient (JSC) were used to evaluate the spatial overlap accuracy of the different volume delineations and compared with the benchmark; the Hausdorff distance (HD) and the mean distance to agreement (MDA) to explore the distance between contours. All the results were reported as sample mean and standard deviation (SD). Results: Fifteen radiation oncologists from different Institutions joined the study. The participants had a high agreement degree for pelvic bones sub-structures delineation according to DICE (IBM: 0.9 +/- 0.02; LPBM: 0.91 +/- 0.01). A moderate degree according to DICE was showed for ovaries (Right: 0.61 +/- 0.16, Left: 0.72 +/- 0.05), vagina (0.575 +/- 0.13), bladder sub-structures (0.515 +/- 0.08) and EAS (0.605 +/- 0.05), whereas a low degree for the other sub-structures of the anal-rectal sphincter complex (LAM: 0.345 +/- 0.07, PRM: 0.41 +/- 0.10, and IAS: 0.4 +/- 0.07).Conclusion: This study found a moderate to low level of agreement in the delineation of the female pelvis emerging OARs, with a high degree of variability among observers. The development of delineation tools should be encouraged to improve the routine contouring of these OARs and increase the quality and consistency of radiotherapy planning

PO-0773: Reirradiation by extracranial stereotactic treatment: preliminary results of a dose escalation study

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EP-1430: Phase II study of short-course accelerated palliative radiation therapy for advanced thoracic tumors

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Phase 2 Neoadjuvant Treatment Intensification Trials in Rectal Cancer: A Systematic Review

Purpose: Multiple phase 2 trials of neoadjuvant treatment intensification in locally advanced rectal cancer have reported promising efficacy signals, but these have not translated into improved cancer outcomes in phase 3 trials. Improvements in phase 2 trial design are needed to reduce these false-positive signals. This systematic review evaluated the design of phase 2 trials of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification in locally advanced rectal cancer. Methods and Materials: The PubMed, EMBASE, MEDLINE, and Cochrane Library databases were searched for published phase 2 trials of neoadjuvant treatment intensification from 2004 to 2016. Trial clinical design and outcomes were assessed, with statistical design and compliance rated using a previously published system. Multivariable meta-regression analysis of pathologic complete response (pCR) was conducted. Results: We identified 92 eligible trials. Patients with American Joint Committee on Cancer stage II and III equivalent disease were eligible in 87 trials (94.6%). In 43 trials (46.7%), local staging on magnetic resonance imaging was mandated. Only 12 trials (13.0%) were randomized, with 8 having a standard-treatment control arm. Just 51 trials (55.4%) described their statistical design, with 21 trials (22.8%) failing to report their sample size derivation. Most trials (n=84, 91.3%) defined a primary endpoint, but 15 different primary endpoints were used. All trials reported pCR rates. Only 38 trials (41.3%) adequately reported trial statistical design and compliance. Meta-analysis revealed a pooled pCR rate of 17.5% (95% confidence interval, 15.7%-19.4%) across treatment arms of neoadjuvant long-course radiation or chemoradiation therapy treatment intensification and substantial heterogeneity among the reported effect sizes (I2 = 55.3%, P<.001). Multivariable meta-regression analysis suggested increased pCR rates with higher radiation therapy doses (adjusted P=.025). Conclusions: Improvement in the design of future phase 2 rectal cancer trials is urgently required. A significant increase in randomized trials is essential to overcome selection bias and determine novel schedules suitable for phase 3 testing. This systematic review provides key recommendations to guide future treatment intensification trial design in rectal cancer