Analysis of left ventricle regional myocardial motion for cardiac radioablation: Left ventricular motion analysis.

PURPOSE: Left ventricle (LV) regional myocardial displacement due to cardiac motion was assessed using cardiovascular magnetic resonance (CMR) cine images to establish region-specific margins for cardiac radioablation treatments. METHODS: CMR breath-hold cine images and LV myocardial tissue contour points were analyzed for 200 subjects, including controls (n = 50) and heart failure (HF) patients with preserved ejection fraction (HFpEF, n = 50), mid-range ejection fraction (HFmrEF, n = 50), and reduced ejection fraction (HFrEF, n = 50). Contour points were divided into segments according to the 17-segment model. For each patient, contour point displacements were determined for the long-axis (all 17 segments) and short-axis (segments 1-12) directions. Mean overall, tangential (longitudinal or circumferential), and normal (radial) displacements were calculated for the 17 segments and for each segment level. RESULTS: The greatest overall motion was observed in the control group-long axis: 4.5 ± 1.2 mm (segment 13 [apical anterior] epicardium) to 13.8 ± 3.0 mm (segment 6 [basal anterolateral] endocardium), short axis: 4.3 ± 0.8 mm (segment 9 [mid inferoseptal] epicardium) to 11.5 ± 2.3 mm (segment 1 [basal anterior] endocardium). HF patients exhibited lesser motion, with the smallest overall displacements observed in the HFrEF group-long axis: 4.3 ± 1.7 mm (segment 13 [apical anterior] epicardium) to 10.6 ± 3.4 mm (segment 6 [basal anterolateral] endocardium), short axis: 3.9 ± 1.3 mm (segment 8 [mid anteroseptal] epicardium) to 7.4 ± 2.8 mm (segment 1 [basal anterior] endocardium). CONCLUSIONS: This analysis provides an estimate of epicardial and endocardial displacement for the 17 segments of the LV for patients with normal and impaired LV function. This reference data can be used to establish treatment planning margin guidelines for cardiac radioablation. Smaller margins may be used for patients with higher degree of impaired heart function, depending on the LV segment.

Single vs. multiple fraction non-inferiority trial of stereotactic ablative radiotherapy for the comprehensive treatment of oligo-metastases/progression: SIMPLIFY-SABR-COMET.

BACKGROUND: Radiotherapy delivery regimens can vary between a single fraction (SF) and multiple fractions (MF) given daily for up to several weeks depending on the location of the cancer or metastases. With limited evidence comparing fractionation regimens for oligometastases, there is support to explore toxicity levels to nearby organs at risk as a primary outcome while using SF and MF stereotactic ablative radiotherapy (SABR) as well as explore differences in patient-reported quality of life and experience. METHODS: This study will randomize 598 patients in a 1:1 ratio between the standard arm (MF SABR) and the experimental arm (SF SABR). This trial is designed as two randomized controlled trials within one patient population for resource efficiency. The primary objective of the first randomization is to determine if SF SABR is non-inferior to MF SABR, with respect to healthcare provider (HCP)-reported grade 3-5 adverse events (AEs) that are related to SABR. Primary endpoint is toxicity while secondary endpoints include lesional control rate (LCR), and progression-free survival (PFS). The second randomization (BC Cancer sites only) will allocate participants to either complete quality of life (QoL) questionnaires only; or QoL questionnaires and a symptom-specific survey with symptom-guided HCP intervention. The primary objective of the second randomization is to determine if radiation-related symptom questionnaire-guided HCP intervention results in improved reported QoL as measured by the EuroQoL-5-dimensions-5levels (EQ-5D-5L) instrument. The primary endpoint is patient-reported QoL and secondary endpoints include: persistence/resolution of symptom reporting, QoL, intervention cost effectiveness, resource utilization, and overall survival. DISCUSSION: This study will compare SF and MF SABR in the treatment of oligometastases and oligoprogression to determine if there is non-inferior toxicity for SF SABR in selected participants with 1-5 oligometastatic lesions. This study will also compare patient-reported QoL between participants who receive radiation-related symptom-guided HCP intervention and those who complete questionnaires alone. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT05784428. Date of Registration: 23 March 2023.

Left ventricle segment-specific motion assessment for cardiac-gated radiosurgery.

Purpose.Cardiac radiosurgery is a non-invasive treatment modality for ventricular tachycardia, where a linear accelerator is used to irradiate the arrhythmogenic region within the heart. In this work, cardiac magnetic resonance (CMR) cine images were used to quantify left ventricle (LV) segment-specific motion during the cardiac cycle and to assess potential advantages of cardiac-gated radiosurgery.Methods.CMR breath-hold cine images and LV contour points were analyzed for 50 controls and 50 heart failure patients with reduced ejection fraction (HFrEF, EF < 40%). Contour points were divided into anatomic segments according to the 17-segment model, and each segment was treated as a hypothetical treatment target. The optimum treatment window (one fifth of the cardiac cycle) was determined where segment centroid motion was minimal, then the maximum centroid displacement and treatment area were determined for the full cardiac cycle and for the treatment window. Mean centroid displacement and treatment area reductions with cardiac gating were determined for each of the 17 segments.Results.Full motion segment centroid displacements ranged between 6-14 mm (controls) and 4-11 mm (HFrEF). Full motion treatment areas ranged between 129-715 mm2(controls) and 149-766 mm2(HFrEF). With gating, centroid displacements were reduced to 1 mm (controls and HFrEF), while treatment areas were reduced to 62-349 mm2(controls) and 83-393 mm2(HFrEF). Relative treatment area reduction ranged between 38%-53% (controls) and 26%-48% (HFrEF).Conclusion.This data demonstrates that cardiac cycle motion is an important component of overall target motion and varies depending on the anatomic cardiac segment. Accounting for cardiac cycle motion, through cardiac gating, has the potential to significantly reduce treatment volumes for cardiac radiosurgery.

Upfront Versus Delayed Systemic Therapy in Patients With Oligometastatic Cancer Treated With SABR in the Phase 2 SABR-5 Trial.

PURPOSE: The optimal sequencing of local and systemic therapy for oligometastatic cancer has not been established. This study retrospectively compared progression-free survival (PFS), overall survival (OS), and SABR-related toxicity between upfront versus delay of systemic treatment until progression in patients in the SABR-5 trial. METHODS AND MATERIALS: The single-arm phase 2 SABR-5 trial accrued patients with up to 5 oligometastases across SABR-5 between November 2016 and July 2020. Patients received SABR to all lesions. Two cohorts were retrospectively identified: those receiving upfront systemic treatment along with SABR and those for whom systemic treatment was delayed until disease progression. Patients treated for oligoprogression were excluded. Propensity score analysis with overlap weighting balanced baseline characteristics of cohorts. Bootstrap sampling and Cox regression models estimated the association of delayed systemic treatment with PFS, OS, and grade ≥2 toxicity. RESULTS: A total of 319 patients with oligometastases underwent treatment on SABR-5, including 121 (38%) and 198 (62%) who received upfront and delayed systemic treatment, respectively. In the weighted sample, prostate cancer was the most common primary tumor histology (48%) followed by colorectal (18%), breast (13%), and lung (4%). Most patients (93%) were treated for 1 to 2 metastases. The median follow-up time was 34 months (IQR, 24-45). Delayed systemic treatment was associated with shorter PFS (hazard ratio [HR], 1.56; 95% CI, 1.15-2.13; P = .005) but similar OS (HR, 0.90; 95% CI, 0.51-1.59; P = .65) compared with upfront systemic treatment. Risk of grade 2 or higher SABR-related toxicity was reduced with delayed systemic treatment (odds ratio, 0.35; 95% CI, 0.15-0.70; P < .001). CONCLUSIONS: Delayed systemic treatment is associated with shorter PFS without reduction in OS and with reduced SABR-related toxicity and may be a favorable option for select patients seeking to avoid initial systemic treatment. Efforts should continue to accrue patients to histology-specific trials examining a delayed systemic treatment approach.

Canadian Consensus Recommendations on the Management of Extensive-Stage Small-Cell Lung Cancer.

Small-cell lung cancer (SCLC) is an aggressive, neuroendocrine tumour with high relapse rates, and significant morbidity and mortality. Apart from advances in radiation therapy, progress in the systemic treatment of SCLC had been stagnant for over three decades despite multiple attempts to develop alternative therapeutic options that could improve responses and survival. Recent promising developments in first-line and subsequent therapeutic approaches prompted a Canadian Expert Panel to convene to review evidence, discuss practice patterns, and reach a consensus on the treatment of extensive-stage SCLC (ES-SCLC). The literature search included guidelines, systematic reviews, and randomized controlled trials. Regular meetings were held from September 2022 to March 2023 to discuss the available evidence to propose and agree upon specific recommendations. The panel addressed biomarkers and histological features that distinguish SCLC from non-SCLC and other neuroendocrine tumours. Evidence for initial and subsequent systemic therapies was reviewed with consideration for patient performance status, comorbidities, and the involvement and function of other organs. The resulting consensus recommendations herein will help clarify evidence-based management of ES-SCLC in routine practice, help clinician decision-making, and facilitate the best patient outcomes.

Follow-Up Imaging Guidelines for Patients with Stage III Unresectable NSCLC: Recommendations Based on the PACIFIC Trial.

The PACIFIC trial showed a survival benefit with durvalumab through five years in stage III unresectable non-small cell lung cancer (NSCLC). However, optimal use of imaging to detect disease progression remains unclearly defined for this population. An expert working group convened to consider available evidence and clinical experience and develop recommendations for follow-up imaging after concurrent chemotherapy and radiation therapy (CRT). Voting on agreement was conducted anonymously via online survey. Follow-up imaging was recommended for all suitable patients after CRT completion regardless of whether durvalumab is received. Imaging should occur every 3 months in Year 1, at least every 6 months in Year 2, and at least every 12 months in Years 3-5. Contrast computed tomography was preferred; routine brain imaging was not recommended for asymptomatic patients. The medical oncologist should follow-up during Year 1 of durvalumab therapy, with radiation oncologist involvement if pneumonitis is suspected; medical and radiation oncologists can subsequently alternate follow-up. Some patients can transition to the family physician/community primary care team at the end of Year 2. In Years 1-5, patients should receive information regarding smoking cessation, comorbidity management, vaccinations, and general follow-up care. These recommendations provide guidance on follow-up imaging for patients with stage III unresectable NSCLC whether or not they receive durvalumab consolidation therapy.

Use of radiation therapy among patients with Extensive-stage Small-cell lung cancer receiving Immunotherapy: Canadian consensus recommendations.

OBJECTIVES: Thoracic radiation therapy (TRT) and prophylactic cranial irradiation (PCI) are commonly used in the management of extensive-stage small-cell lung cancer (ES-SCLC); however, Phase III trials of first-line immunotherapy often excluded these options. Guidance is needed regarding appropriate use of TRT, PCI, and magnetic resonance imaging (MRI) surveillance while new data are awaited. MATERIALS AND METHODS: In two web-based meetings, a pan-Canadian expert working group of five radiation oncologists and four medical oncologists addressed eight clinical questions regarding use of radiation therapy (RT) and MRI surveillance among patients with ES-SCLC receiving immunotherapy. A targeted literature review was conducted using PubMed and conference proceedings to identify recent (January 2019-April 2022) publications in this setting. Fifteen recommendations were developed; online voting was conducted to gauge agreement with each recommendation. RESULTS: After considering recently available evidence across lung cancer populations and clinical experience, the experts recommended that all patients with a response to chemo-immunotherapy, good performance status (PS), and limited metastases be considered for consolidation TRT (e.g., 30 Gy in 10 fractions). When considered appropriate after multidisciplinary team discussion, TRT can be initiated during maintenance immunotherapy. All patients who respond to concurrent chemo-immunotherapy should undergo restaging with brain MRI to guide decision-making regarding PCI versus MRI surveillance alone. MRI surveillance should be conducted for two years after response to initial therapy. PCI (e.g., 25 Gy in 10 fractions or 20 Gy in 5 fractions) can be considered for patients without central nervous system involvement who have a response to chemo-immunotherapy and good PS. Concurrent treatment with PCI and immunotherapy or with TRT, PCI, and immunotherapy is appropriate after completion of initial therapy. All recommendations were agreed upon unanimously. CONCLUSIONS: These consensus recommendations provide practical guidance regarding appropriate use of RT and immunotherapy in ES-SCLC while awaiting new clinical trial data.

Should organs at risk (OARs) be prioritized over target volume coverage in stereotactic ablative radiotherapy (SABR) for oligometastases? a secondary analysis of the population-based phase II SABR-5 trial.

BACKGROUND AND PURPOSE: Stereotactic ablative radiotherapy (SABR) for oligometastases may improve survival, however concerns about safety remain. To mitigate risk of toxicity, target coverage was sacrificed to prioritize organs-at-risk (OARs) during SABR planning in the population-based SABR-5 trial. This study evaluated the effect of this practice on dosimetry, local recurrence (LR), and progression-free survival (PFS). METHODS: This single-arm phase II trial included patients with up to 5 oligometastases between November 2016 and July 2020. Theprotocol-specified planning objective was to cover 95 % of the planning target volume (PTV) with 100 % of the prescribed dose, however PTV coverage was reduced as needed to meet OAR constraints. This trade-off was measured using the coverage compromise index (CCI), computed as minimum dose received by the hottest 99 % of the PTV (D99) divided by the prescription dose. Under-coverage was defined as CCI < 0.90. The potential association between CCI and outcomes was evaluated. RESULTS: 549 lesions from 381 patients were assessed. Mean CCI was 0.88 (95 % confidence interval [CI], 0.86-0.89), and 196 (36 %) lesions were under-covered. The highest mean CCI (0.95; 95 %CI, 0.93-0.97) was in non-spine bone lesions (n = 116), while the lowest mean CCI (0.71; 95 % CI, 0.69-0.73) was in spine lesions (n = 104). On multivariable analysis, under-coverage did not predict for worse LR (HR 0.48, p = 0.37) or PFS (HR 1.24, p = 0.38). Largest lesion diameter, colorectal and 'other' (non-prostate, breast, or lung) primary predicted for worse LR. Largest lesion diameter, synchronous tumor treatment, short disease free interval, state of oligoprogression, initiation or change in systemic treatment, and a high PTV Dmax were significantly associated with PFS. CONCLUSION: PTV under-coverage was not associated with worse LR or PFS in this large, population-based phase II trial. Combined with low toxicity rates, this study supports the practice of prioritizing OAR constraints during oligometastatic SABR planning.

Stereotactic Ablative Radiation Therapy for Colorectal Liver Metastases.

INTRODUCTION: Stereotactic Ablative Radiation Therapy (SABR) is a therapeutic option for patients with inoperable oligometastatic colorectal carcinoma (CRC). Given the scarcity of prospective data on outcomes of SABR for metastatic CRC, this study aims to review SABR outcomes and determine predictive factors of local control (LC) and survival in patients with liver metastases from CRC. MATERIALS AND METHODS: A retrospective review of SABR for CRC liver metastases between 2011 and 2019 was undertaken. Endpoints included LC, overall survival (OS), progression-free survival (PFS) and time to restarting systemic therapy. Univariate (UVA) and multivariable analyses (MVA) were performed to identify predictive factors. RESULTS: Forty-eight patients were identified. The total number of tumors treated was 58. Median follow-up was 26.6 months. LC at 1, 2 and 3 years was 92.7%, 80.0%, and 61.2% respectively. Median time to local failure was 40.0 months (95% CI 31.8-76.1 months). Median OS was 31.9 months (95% CI 20.6-40.0 months). OS at 1, 2, and 3 years was 79.2%, 61.7%, and 44.9% respectively. Thirty-three patients (69%) restarted systemic therapy after completion of SABR. Median time to restarting chemotherapy was 11.0 months (95% CI 7.1-17.6 months). Systemic therapy free survival at 1, 2, and 3 years was 45.7%, 29.6%, and 22.6% respectively. On MVA, inferior LC was influenced by GTV volume ≥40 cm3 (HR: 3.805, 95% CI 1.376-10.521, P = .01) and PTV D100% BED <100 Gy10 (HR 2.971, 95% CI 1.110-7.953; P = .03). Inferior OS was associated with PTV volume ≥200 cm3 (HR 5.679, 95% CI 2.339-13.755; P < .001). CONCLUSION: SABR is an effective therapeutic option for selected patients with CRC liver metastases providing acceptable LC within the first 2 years. In many cases, it provides meaningful chemotherapy-free intervals. Higher biological effective doses are required to enhance LC.

Treatment With Stereotactic Ablative Radiotherapy for Up to 5 Oligometastases in Patients With Cancer: Primary Toxic Effect Results of the Nonrandomized Phase 2 SABR-5 Clinical Trial.

Importance: After the publication of the landmark SABR-COMET trial, concerns arose regarding high-grade toxic effects of treatment with stereotactic ablative body radiotherapy (SABR) for oligometastases. Objective: To document toxic effects of treatment with SABR in a large cohort from a population-based, provincial cancer program. Design, Setting, and Participants: From November 2016 to July 2020, 381 patients across all 6 cancer centers in British Columbia were treated in this single-arm, phase 2 trial of treatment with SABR for patients with oligometastatic or oligoprogressive disease. During this period, patients were only eligible to receive treatment with SABR in these settings in trials within British Columbia; therefore, this analysis is population based, with resultant minimal selection bias compared with previously published SABR series. Interventions: Stereotactic ablative body radiotherapy to up to 5 metastases. Main Outcomes and Measures: Rate of grade 2, 3, 4, and 5 toxic effects associated with SABR. Findings: Among 381 participants (122 women [32%]), the mean (SD; range) age was 68 (11.1; 30-97) years, and the median (range) follow-up was 25 (1-54) months. The most common histological findings were prostate cancer (123 [32%]), colorectal cancer (63 [17%]), breast cancer (42 [11%]), and lung cancer (33 [9%]). The number of SABR-treated sites were 1 (263 [69%]), 2 (82 [22%]), and 3 or more (36 [10%]). The most common sites of SABR were lung (188 [34%]), nonspine bone (136 [25%]), spine (85 [16%]), lymph nodes (78 [14%]), liver (29 [5%]), and adrenal (15 [3%]). Rates of grade 2, 3, 4, and 5 toxic effects associated with SABR (based on the highest-grade toxic effect per patient) were 14.2%; (95% CI, 10.7%-17.7%), 4.2% (95% CI, 2.2%-6.2%), 0%, and 0.3% (95% CI, 0%-0.8%), respectively. The cumulative incidence of grade 2 or higher toxic effects associated with SABR at year 2 by Kaplan-Meier analysis was 8%, and for grade 3 or higher, 4%. Conclusions and Relevance: This single-arm, phase 2 clinical trial found that the incidence of grade 3 or higher SABR toxic effects in this population-based study was less than 5%. Furthermore, the rates of grade 2 or higher toxic effects (18.6%) were lower than previously published for SABR-COMET (29%). These results suggest that SABR treatment for oligometastases has acceptable rates of toxic effects and potentially support further enrollment in randomized phase 3 clinical trials. Trial Registration: ClinicalTrials.gov Identifier: NCT02933242.

Predictors of Early Polymetastatic Relapse After SABR for up to 5 Oligometastases: A Secondary Analysis of the Phase II SABR-5 Trial.

PURPOSE: A subset of patients with oligometastatic cancer experience early widespread cancer dissemination and do not benefit from metastasis-directed therapy such as SABR. This study aimed to identify factors associated with early polymetastatic relapse (PMR). METHODS AND MATERIALS: The SABR-5 trial was a single arm phase 2 study conducted at all 6 regional cancer centers across British Columbia (BC), Canada. SABR for oligometastases was only offered on trial. Patients with up to 5 oligometastatic lesions (total, progressing, or induced) received SABR to all lesions. Patients were 18 years of age or older, Eastern Cooperative Oncology Group 0 to 2 and life expectancy ≥6 months. This secondary analysis evaluated factors associated with early PMR, defined as disease recurrence within 6 months of SABR, which is not amenable to further local treatment. Univariable and multivariable analyses were performed using binary logistic regression. The Kaplan-Meier method and log-rank tests assessed PMR-free survival and differences between risk groups, respectively. RESULTS: Between November 2016 and July 2020, 381 patients underwent treatment on SABR-5. A total of 16% of patients experienced PMR. Worse performance status (Eastern Cooperative Oncology Group 1-2 vs 0; hazard ratio [HR] = 2.01, P = .018), nonprostate/breast histology (HR = 3.64, P <.001), and oligoprogression (HR = 3.84, P <.001) were independent predictors for early PMR. Risk groups were identified with median PMR-free survival ranging from 5 months to not yet reached at the time of analysis. Rates of 3-year overall survival were 0%, 53% (95% confidence interval [CI], 48-58), 77% (95% CI, 73-81), and 93% (95% CI, 90-96) in groups 1 to 4, respectively (P <.001). CONCLUSIONS: Four distinct risk groups for early PMR are identified, which differ significantly in PMR-free survival and overall survival. The group with all 3 risk factors had a median PMR-free survival of 5 months and may not benefit from local ablative therapy alone. This model should be externally validated with data from other prospective trials.

Stereotactic Radiation for the Comprehensive Treatment of Oligometastases (SABR-COMET): Extended Long-Term Outcomes.

PURPOSE: Long-term randomized data assessing the effect of ablative therapies in patients with oligometastases are lacking. The Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastases (SABR-COMET) randomized phase 2 trial was originally designed with 5 years of follow-up, but the trial was amended in 2016 to extend follow-up to 10 years. Herein we report oncologic outcomes beyond 5 years. METHODS AND MATERIALS: Patients were eligible if they had a controlled primary tumor and 1 to 5 metastases, with all metastases amenable to SABR. Patients were randomized in a 1:2 ratio between palliative standard-of-care treatment (control arm) versus SABR to all metastases plus standard of care (SABR arm). The primary endpoint was overall survival (OS) and secondary endpoints included progression-free survival (PFS), toxicity, quality of life (using the Functional Assessment of Cancer Therapy: General [FACT-G]), and time to new metastases. RESULTS: Ninety-nine patients were randomized between 2012 and 2016 (n = 33 in arm 1 vs n = 66 in arm 2). Primary tumor sites included lung (n = 18), breast (n = 18), colon (n = 18), prostate (n = 16), and other (n = 29). Eight-year OS was 27.2% in the SABR arm versus 13.6% in the control arm (hazard ratio, 0.50; 95% confidence interval, 0.30-0.84; P = .008). Eight-year PFS estimates were 21.3% versus 0.0%, respectively (hazard ratio, 0.45; 95% confidence interval, 0.28-0.72; P < .001). Rates of grade ≥ 2 acute or late toxic effects were 30.3% versus 9.1% (P = .019), with no new grade 3 to 5 toxic effects. FACT-G quality of life scores declined over time in both arms, but there were no differences in quality of life scores between arms. The use of systemic therapy overall was similar between arms, but patients in the SABR arm were less likely to require cytotoxic chemotherapy (33.3% vs 54.6%, respectively, P = .043). CONCLUSIONS: SABR achieved durable improvements in OS and PFS, with no new major toxicity signals with extended follow-up. A minority of patients randomized to the SABR arm (21.3%) achieved > 5 years of survival without recurrence.

Progression-Free Survival and Local Control After SABR for up to 5 Oligometastases: An Analysis From the Population-Based Phase 2 SABR-5 Trial.

PURPOSE: Despite increasing utilization of SABR for oligometastatic cancer, prospective outcomes are lacking. The purpose of this study was to determine progression-free survival (PFS), local control (LC), and prognostic factors from the population-based phase 2 SABR-5 trial. METHODS AND MATERIALS: The SABR-5 trial was a single-arm phase 2 study with the primary endpoint of toxicity, conducted at the 6 regional cancer centers across British Columbia (BC), Canada, during which time SABR for oligometastases was only offered on trial. Patients with up to 5 oligometastases (total or not controlled by prior treatment and including induced oligometastatic disease) underwent SABR to all lesions. Patients were 18 years of age or older, had an Eastern Cooperative Oncology Group score of 0 to 2, and had life expectancy ≥ 6 months. The secondary outcomes of PFS and LC are presented here. RESULTS: Between November 2016 and July 2020, 381 patients underwent SABR on trial. Median follow-up was 27 months (interquartile range, 18-36). Median PFS was 15 months (95% confidence interval [CI], 12-18). LC at 1 and 3 years were 93% (95% CI, 91-95) and 87% (95% CI, 84-90), respectively. On multivariable analysis, increasing tumor diameter (hazard ratio [HR], 1.09; P < .001), declining performance status (HR, 2.13; P < .001), disease-free interval <18 months (HR, 1.52; P = .003), 4 or more metastases at SABR (HR, 1.48; P = .048), initiation or change in systemic treatment (HR, 0.50; P < .001), and oligoprogression (HR, 1.56; P = .008) were significant independent predictors of PFS. Tumor diameter (sub-hazard ratio [SHR], 1.28; P < .001), colorectal histology (SHR, 4.33; P = .002), and "other" histology (SHR, 3.90; P < .001) were associated with worse LC. CONCLUSIONS: In this population-based cohort including patients with genuine oligometastatic, oligoprogressive, and induced oligometastatic disease, the median PFS was 15 months and LC at 3 years was 87%. This supports ongoing efforts to randomize patients in phase 3 trials, even outside the original 1 to 5 metachronous oligometastatic paradigm.

Current Role of Immunotherapy in Gastric, Esophageal and Gastro-Esophageal Junction Cancers-A Report from the Western Canadian Gastrointestinal Cancer Consensus Conference.

Gastric, esophageal and gastro-esophageal junction cancers are associated with inferior outcomes. For early-stage disease, perioperative chemotherapy or chemoradiation followed by surgery is the standard treatment. For most patients with advanced upper gastrointestinal tract cancers, platinum-based chemotherapy remains a standard treatment. Recently, several randomized clinical trials have demonstrated the benefit of immunotherapy involving checkpoint inhibitors alone or in combination with chemotherapy in patients with gastro-esophageal cancer and have changed the treatment landscape. The Western Canadian Gastrointestinal Cancer Consensus Conference (WCGCCC), involving experts from four Western Canadian provinces, convened virtually on 16 June 2021 and developed the recommendations on the role of immunotherapy in patients with gastro-esophageal cancer.

Systemic Therapy and Its Surgical Implications in Patients with Resectable Liver Colorectal Cancer Metastases. A Report from the Western Canadian Gastrointestinal Cancer Consensus Conference.

The Western Canadian Gastrointestinal Cancer Consensus Conference (WCGCCC) convened virtually on 4 November 2021. The WCGCCC is an interactive multi-disciplinary conference attended by health care professionals, including surgical, medical, and radiation oncologists; pathologists; radiologists; and allied health care professionals from across four Western Canadian provinces, British Columbia, Alberta, Saskatchewan, and Manitoba, who are involved in the care of patients with gastrointestinal cancer. They participated in presentation and discussion sessions for the purpose of developing recommendations on the role of systemic therapy and its optimal sequence in patients with resectable metastatic colorectal cancer.

Report from the Western Canadian Gastrointestinal Consensus Cancer Conference-Management of Total Neoadjuvant Therapy in Rectal Cancer.

An educational session related to the Western Canadian Gastrointestinal Cancer Consensus Conference (WCGCCC) was held virtually on 14 October 2020. The WCGCCC is an interactive multidisciplinary conference attended by health care professionals from across Western Canada (British Columbia, Alberta, Saskatchewan, and Manitoba), who are involved in the care of patients with gastrointestinal cancer. Surgical, medical, and radiation oncologists; pathologists, radiologists, and allied health care professionals participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of total neoadjuvant therapy in rectal cancer.

Report from the Western Canadian Gastrointestinal Cancer Consensus Conference Virtual Education Series-Transition from Local to System Therapy and Optimal Sequencing of Systemic Therapy for HCC.

The Western Canadian Gastrointestinal Cancer Consensus Conference (WC-5) convened virtually on 10 February 2021. The WC-5 is an interactive multidisciplinary conference attended by health care professionals from across Western Canada (British Columbia, Alberta, Saskatchewan, and Manitoba) who are involved in the care of patients with gastrointestinal cancer. Surgical, medical, and radiation oncologists; pathologists; radiologists; and allied health care professionals participated in presentation and discussion sessions for the purpose of developing the recommendations presented here. This consensus statement addresses current issues in the management of hepatocellular cancer (HCC). Recommendations have been made for the transition from local to systemic therapy and the optimal sequencing of systemic regimens in the management of HCC.

A Canadian Perspective on the Challenges for Delivery of Curative-Intent Therapy in Stage III Unresectable Non-Small Cell Lung Cancer.

Stage III non-small cell lung cancer (NSCLC) comprises a highly heterogenous group of patients with regards to patient fitness and tumour size and distribution, resulting in a wide range of treatment goals and therapy options. Curative-intent multimodality treatment should be considered in all patients with stage III NSCLC. For patients with unresectable disease who are fit, have adequate lung function, and have a disease that can be encompassed within a radical radiation volume, concurrent chemoradiation therapy (cCRT) is the standard of care and can produce cure rates of 20-30%. Recently, consolidation immunotherapy with durvalumab has been recognized as the standard of care following cCRT based on significant improvement rates in overall survival at 4 years. The large heterogeneity of the stage III NSCLC population, along with the need for extensive staging procedures, multidisciplinary care, intensive cCRT, and now consolidation therapy makes the delivery of timely and optimal treatment for these patients complex. Several logistical, communication, and education factors hinder the delivery of guideline-recommended care to patients with stage III unresectable NSCLC. This commentary discusses the potential challenges patients may encounter at different points along their care pathway that can interfere with delivery of curative-intent therapy and suggests strategies for improving care delivery.

Practical Considerations for the Implementation of a Stereotactic Body Radiation Therapy Program for Oligo-Metastases.

PURPOSE: With multiple phase 2 trials supporting the use of stereotactic body radiation therapy (SBRT) in oligo-metastatic disease, we evaluated practices that could inform effective implementation of an oligo-metastasis SBRT program. METHODS AND MATERIALS: Using a context-focused realist methodology, an advisory committee of interprofessional clinicians met over a series of semistructured teleconference meetings to identify challenges in implementing an oligo-metastasis SBRT program. Consideration was given to 2 models of care: a subspecialist anatomic expertise model versus a single-practitioner "quarterback" model. RESULTS: The advisory committee structured recommendations within a context-mechanism-outcome framework. In summary, the committee recommends that during patient workup, a single practitioner arranges the minimum number of necessary tests, with case presentation at an appropriate multidisciplinary tumor board, including careful review of all previous treatments, and enrollment on clinical trials when possible. At simulation, common patient positions and immobilization on a single simulation scan for multiple sites is recommended. During radiation planning, dose-fractionation regimens should safely facilitate cumulative dose calculations, a single isocenter should be considered for multiple close targets to reduce treatment time, and adherence to strict quality assurance protocols is strongly recommended. Treatment duration should be minimized by treating multiple sites on the same day or choosing shorter dose fractionations. Team communication, thorough documentation, and standardized nomenclature can reduce system errors. Follow-up should aim to minimize redundant clinical appointments and imaging scans. Expert radiology review may be required to interpret post-SBRT imaging. CONCLUSIONS: These guidelines inform best clinical practices for implementing an oligo-metastasis SBRT program. Iterations using a realist approach may further expand on local contexts.

Is SABR Cost-Effective in Oligometastatic Cancer? An Economic Analysis of the SABR-COMET Randomized Trial.

PURPOSE: The phase 2 randomized study SABR-COMET demonstrated that in patients with controlled primary tumors and 1 to 5 oligometastatic lesions, SABR was associated with improved progression-free survival (PFS) compared with standard of care (SoC), but with higher costs and treatment-related toxicities. The aim of this study was to assess the cost-effectiveness of SABR versus SoC in this setting. METHODS AND MATERIALS: A Markov model was constructed to perform a cost-utility analysis from the Canadian health care system perspective. Utility values and transition probabilities were derived from individual-level data from the SABR-COMET trial. One-way, 2-way, and probabilistic sensitivity analyses were performed. Costs were expressed in 2018 CAD. A separate analysis based on US payer's perspective was performed. An incremental cost-effectiveness ratio (ICER) at a willingness-to-pay threshold of $100,000 per quality-adjusted life year (QALY) was used. RESULTS: In the base case scenario, SABR was cost-effective at an ICER of $37,157 per QALY gained. This finding was most sensitive to the number of metastatic lesions treated with SABR (ICER: $28,066 per QALY for 2, increasing to $64,429 per QALY for 5), difference in chemotherapy use (ICER: $27,173-$53,738 per QALY), and PFS hazard ratio (HR) between strategies (ICER: $31,548-$53,273 per QALY). Probabilistic sensitivity analysis revealed that SABR was cost-effective in 97% of all iterations. Two-way sensitivity analysis demonstrated a nonlinear relationship between the number of lesions and the PFS HR. To maintain cost-effectiveness for each additional metastasis, the HR must decrease by approximately 0.047. The US cost analysis yielded similar results, with an ICER of $54,564 (2018 USD per QALY) for SABR. CONCLUSIONS: SABR is cost-effective for patients with 1 to 5 oligometastatic lesions compared with SoC.