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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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

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., (Copyright © 2022 Elsevier Inc. All rights reserved.)

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.

Objective: To describe the experiences of patients with lung cancer with a volunteer-based lay navigation intervention., Methods: Forty patients with newly diagnosed lung cancer enrolled in a three-step navigation intervention delivered by trained volunteer lay navigators (VLNs), beginning prior to their first oncologist's appointment and ending before the start of treatment. Methodological triangulation of data was used in a mixed method study design. Cases were categorized based on the predominant needs met by the VLN: emotional, practical/informational, family, and complex. Data were analyzed using framework analysis., Results: The provision of emotional support, information, and referrals to other services by the VLN were of particular benefit to the patient and their families. Satisfaction with the program and its timing was high; it was considered an effective means for patients to share concerns and have their needs attended to before starting treatment., Conclusion: This study demonstrates capacity for lay volunteers to address the multifaceted needs of lung cancer patients during their transition from primary care in the diagnosis to treatment phase., Practice Implications: Using volunteers as navigators offers an opportunity to meet patient needs with minimal resources, increase access to services for patients, and improve the sustainability of the program., (Crown Copyright © 2014. Published by Elsevier Ireland Ltd. All rights reserved.)

Introduction: Although the value of peer review is increasingly recognized, there is little research documenting its impact in the setting of stereotactic body radiation therapy (SBRT) for lung cancer. This study determines the dosimetric effect of peer review of tumor and normal tissue contouring in lung SBRT planning., Methods: Forty anonymized lung SBRT plans were retrospectively evaluated post treatment. Each plan was independently reviewed by two to three radiation oncologists using established institutional guidelines. For each structure, reviewers recorded recommendations for "no change," "minor change," "major change," or "missing contour" and provided a modified or new contour as needed. Dose-volume histograms were analyzed for dosimetric violations., Results: Among 472 contoured structures evaluated, recommendations from peer review were 107 major change (23%), 176 minor change (37%), 157 no change (33%), and 32 missing (7%). Common major changes involved the skin (n = 20), heart (n = 18), and proximal bronchial tree (n = 15). Dose constraints were not achieved for 25 new or recontoured structures (5%), of which 17 involved the planning target volume (PTV). Among cases with PTV violations, the mean prescription dose coverage to the modified PTVs was 90%, compared with the protocol standard of greater than or equal to 95% coverage. The remaining violations involved the ribs (n = 5), spinal canal (n = 2), and heart (n = 1)., Conclusions: Peer review of structure contouring resulted in significant changes in lung SBRT plans. Recontouring of several plans revealed violations of dose limits, most often involving inadequate PTV coverage. Peer review, especially of target volume delineation, is warranted to improve consistency and quality in lung SBRT planning.

Background: The purpose of this study is to evaluate the clinical impact of using deformable registration in tumor volume definition between separately acquired PET/CT and planning CT images., Methods: Ten lung and 10 head and neck cancer patients were retrospectively selected. PET/CT images were registered with planning CT scans using commercially available software. Radiation oncologists defined two sets of gross tumor volumes based on either rigidly or deformably registered PET/CT images, and properties of these volumes were then compared., Results: The average displacement between rigid and deformable gross tumor volumes was 1.8 mm (0.7 mm) with a standard deviation of 1.0 mm (0.6 mm) for the head and neck (lung) cancer subjects. The Dice similarity coefficients ranged from 0.76-0.92 and 0.76-0.97 for the head and neck and lung subjects, respectively, indicating conformity. All gross tumor volumes received at least 95% of the prescribed dose to 99% of their volume. Differences in the mean radiation dose delivered to the gross tumor volumes were at most 2%. Differences in the fraction of the tumor volumes receiving 100% of the radiation dose were at most 5%., Conclusions: The study revealed limitations in the commercial software used to perform deformable registration. Unless significant anatomical differences between PET/CT and planning CT images are present, deformable registration was shown to be of marginal value when delineating gross tumor volumes.