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.

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.

Prospective Longitudinal Assessment of Quality of Life After Stereotactic Ablative Radiotherapy for Oligometastases: Analysis of the Population-based SABR-5 Phase II Trial

AIMS

To evaluate longitudinal patient-reported quality of life (QoL) in patients treated with stereotactic ablative radiotherapy (SABR) for oligometastases.

MATERIALS AND METHODS

The SABR-5 trial was a population-based single-arm phase II study of SABR to up to five sites of oligometastases, conducted in six regional cancer centres in British Columbia, Canada from 2016 to 2020. Prospective QoL was measured using treatment site-specific QoL questionnaires at pre-treatment baseline and at 3, 6, 9, 12, 15, 18, 21, 24, 30 and 36 months after treatment. Patients with bone metastases were assessed with the Brief Pain Inventory (BPI). Patients with liver, adrenal and abdominopelvic lymph node metastases were assessed with the Functional Assessment of Chronic Illness Therapy-Abdominal Discomfort (FACIT-AD). Patients with lung and intrathoracic lymph node metastases were assessed with the Prospective Outcomes and Support Initiative (POSI) lung questionnaire. The two one-sided test procedure was used to assess equivalence between the worst QoL score and the baseline score of individual patients. The mean QoL at all time points was used to determine the trajectory of QoL response after SABR. The proportion of patients with 'stable', 'improved' or 'worsened' QoL was determined for all time points based on standard minimal clinically important differences (MCID; BPI worst pain = 2, BPI functional interference score [FIS] = 0.5, FACIT-AD Trial Outcome Index [TOI] = 8, POSI = 3).

RESULTS

All enrolled patients with baseline QoL assessment and at least one follow-up assessment were analysed (n = 133). On equivalence testing, the patients' worst QoL scores were clinically different from baseline scores and met MCID (BPI worst pain mean difference: 1.8, 90% confidence interval 1.19 to 2.42]; BPI FIS mean difference: 1.68, 90% confidence interval 1.15 to 2.21; FACIT-AD TOI mean difference: -8.76, 90% confidence interval -11.29 to -6.24; POSI mean difference: -4.61, 90% confidence interval -6.09 to -3.14). However, the mean FIS transiently worsened at 9, 18 and 21 months but eventually returned to stable levels. The mean FACIT and POSI scores also worsened at 36 months, albeit with a limited number of responses (n = 4 and 8, respectively). Most patients reported stable QoL at all time points (range: BPI worst pain 71-82%, BPI FIS 45-78%, FACIT-AD TOI 50-100%, POSI 25-73%). Clinically significant stability, worsening and improvement were seen in 70%/13%/18% of patients at 3 months, 53%/28%/19% at 18 months and 63%/25%/13% at 36 months.

CONCLUSIONS

Transient decreases in QoL that met MCID were seen between patients' worst QoL scores and baseline scores. However, most patients experienced stable QoL relative to pre-treatment levels on long-term follow-up. Further studies are needed to characterise patients at greatest risk for decreased QoL.

Predictors of Quality of Life Decline in Patients with Oligometastases treated with Stereotactic Ablative Radiotherapy: Analysis of the Population-Based SABR-5 Phase II Trial

AIMS

Most patients experience stable quality of life (QoL) after stereotactic ablative radiotherapy (SABR) treatment for oligometastases. However, a subset of patients experience clinically relevant declines in QoL on post-treatment follow-up. This study aimed to identify risk factors for QoL decline.

MATERIALS AND METHODS

The SABR-5 trial was a population-based single-arm phase II study of SABR to up to five sites of oligometastases. Prospective QoL was measured using treatment site-specific tools at pre-treatment baseline and 3, 6, 9, 12, 15, 18, 21, 24, 30 and 36 months after treatment. The time to persistent QoL decline was calculated as the time from SABR to the first decline in QoL score meeting minimum clinically important difference with no improvement to baseline score on subsequent assessments. Univariable and multivariable logistic regression analyses were carried out to determine factors associated with QoL decline.

RESULTS

One hundred and thirty-three patients were included with a median follow-up of 32 months (interquartile range 25-43). Thirty-five patients (26%) experienced a persistent decline in QoL. The median time until persistent QoL decline was not reached. The cumulative incidence of QoL decline at 2 and 3 years were 22% (95% confidence interval 14.0-29.6) and 40% (95% confidence interval 28.0-51.2), respectively. In multivariable analysis, disease progression (odds ratio 5.23, 95% confidence interval 1.59-17.47, P = 0.007) and adrenal metastases (odds ratio 9.70, 95% confidence interval 1.41-66.93, P = 0.021) were associated with a higher risk of QoL decline. Grade 3 or higher (odds ratio 3.88, 95% confidence interval 0.92-16.31, P = 0.064) and grade 2 or higher SABR-associated toxicity (odds ratio 2.24, 95% confidence interval 0.85-5.91, P = 0.10) were associated with an increased risk of QoL decline but did not reach statistical significance.

CONCLUSIONS

Disease progression and adrenal lesion site were associated with persistent QoL decline following SABR. The development of grade 3 or higher toxicities was also associated with an increased risk, albeit not statistically significant. Further studies are needed, focusing on the QoL impact of metastasis-directed therapies.

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.

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.

Radiotherapy for Liver Cancer: An International Multi-Centre Pooled Analysis of 925 Cases

PURPOSE/OBJECTIVE(S)

Primary and secondary liver cancer incidence is growing and has a poor prognosis. The standard use of radiation has been hampered by studies with a wide range of patients, different management protocols and varied outcomes. To overcome this heterogeneity in the literature, larger and higher-level trials are warranted, but, so far, have been difficult to implement. Therefore, pooled analyses may offer the best way to determine the benefit of radiation, identify treatment parameters needed to optimize treatment techniques, and identify patient factors that allow for better patient selection.

MATERIALS/METHODS

Patients with liver cancer treated by radiotherapy at centers in Canada, United States and Australia was pooled. Patient and treatment characteristics were noted, as well as the clinical outcomes of local control within 1 year, recurrence and mortality. Stepwise Cox proportional hazards models were used to identify significant predictors for recurrence and mortality. Patients were stratified by center, and primary versus metastatic disease.

RESULTS

A total of 925 patients were included in this study. Mean age was 67 years, and 45% had a primary diagnosis of hepatocellular carcinoma. 1-year local control rate was 80%. Median survival was 1.8 years (1.9 years for primary liver cancer, and 1.4 years for metastatic liver cancer). Higher total dose and BED was associated with better survival. Median time to recurrence was 1.5 years. Higher total dose was associated with lower risk of recurrence CONCLUSION: As one of the largest pooled analyses in hepatic cancer, this international multi-center study provides pragmatic data on clinical outcomes of patients receiving radiotherapy for liver cancer. This database may assist in better selection of patients for future studies and answer questions such as what is the optimal dose and which patients benefit from treatment.

Stereotactic Ablative Radiotherapy for Oligo-Progressive Cancers: Results of the Randomized Phase II STOP Trial

PURPOSE/OBJECTIVE(S)

In the metastatic setting, there is uncertain benefit to localized eradication of one or more lesions that are progressing despite systemic therapy. This randomized phase II trial examined if patients with ≤5 sites of oligoprogression benefited from the addition of stereotactic ablative radiotherapy (SABR) to standard of care (SOC) systemic therapy.

MATERIALS/METHODS

Eligibility criteria included age ≥18 years, ECOG performance status 0-2, and oligoprogressive disease, defined as 1-5 lesions actively progressing while on systemic therapy. Patients were required to have at least 3 months of disease stability/response on systemic therapy prior to oligoprogression. After stratifying by type of systemic therapy (cytotoxic vs. non-cytotoxic), patients were randomized 2:1 to SABR to all progressing lesions plus SOC (SABR arm) vs. SOC alone (SOC arm). The trial began exclusive to non-small cell lung cancer but did not meet accrual goals and was expanded in 2019 to include all non-hematologic malignancies. The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), lesional control, quality of life (QOL), toxicity, and duration of current systemic agent post-SABR.

RESULTS

Between February 2017 and June 2021, 90 patients with 125 oligoprogressive metastases were enrolled across 8 Canadian institutions, with 59 patients randomized to SABR and 31 to SOC. Median age was 67 years (IQR: 61-73 years) and 39 (43%) were female. The most common primary sites were lung (44% of patients), genitourinary (23%) and breast (13%), with the most common oligo-progressive locations being lung (43%), bone (19%), lymph nodes (14%), and liver (13%). In the SABR arm, the most common fractionations were 35 Gy/5 (38% of lesions) and 50 Gy/5 (18%). Protocol adherence in the SOC arm was suboptimal: 3 patients (10%) withdrew immediately after randomization, and 7 additional patients (23%) received high-dose or ablative therapies. Median follow-up was 31 months. There was no difference in PFS between arms (median PFS 8.4 months in the SABR arm vs. 4.3 months in the SOC arm; however, the curves cross and 2-year PFS was 9% vs. 24% respectively, p = 0.91). Median OS was 31.2 months vs. 27.4 months, respectively (p = 0.22). Lesional control with SABR was 71% vs. 39% with SOC (p = 0.002). Median duration of post-randomization first-line systemic therapy was 10.3 months vs. 7.6 months, respectively (p = 0.71). Treatment was well-tolerated with 2 (3.4%) grade 3 treatment-related toxicities in the SABR arm and no grade 4/5 related events in either arm. QOL did not differ between arms.

CONCLUSION

Despite being a well-tolerated treatment providing superior lesional control, SABR for oligoprogression did not improve PFS or OS. Results may have been impacted by withdrawals and desire for ablative treatments on the SOC arm, and this lack of equipoise may make accrual to phase III trials difficult, although larger studies in select sub-populations are desired. (NCT02756793).

Polymetastatic Recurrence-Free Survival in Patients with Repeat Oligometastases on the SABR-5 Trial

PURPOSE/OBJECTIVE(S)

To determine polymetastatic recurrence-free survival (PMRFS) in patients with repeat oligometastases (OM) on the SABR-5 trial.

MATERIALS/METHODS

SABR-5 is a prospective, multi-center trial that evaluated the safety of stereotactic ablative radiotherapy (SABR) in patients with 1-5 OM or oligoprogressive lesions. On SABR-5, patients were followed post-SABR according to standardized protocols. Patients with repeat extra-cranial OM after metastasis-directed therapy (MDT; SABR, surgery, or thermoablation) to all initial OM (including those treated before enrolment on SABR-5) were identified. Exclusion criteria included history of multiple primary malignancies and incomplete re-staging. PMRFS was defined as time from presentation of repeat oligometastases to death or presentation of 6 or more progressing metastases, leptomeningeal metastases, lymphangitic carcinomatosis, malignant ascites, or malignant pleural effusion. PMRFS, overall survival (OS), and progression-free survival (PFS) were calculated using the Kaplan-Meier method.

RESULTS

Seventy-six patients with repeat OM were included, of which 44 (58%) received second MDT to all OM. The most common histology in patients who received second MDT was colorectal cancer (10/44 [23%]) and in those who did not was prostate cancer (17/32 [53%]). Patients who did vs. did not receive second MDT had fewer metastases at repeat OM (mean 1.3 vs 2.2; p<0.001) and no difference in time between initial OM and repeat OM (16 vs. 17 months; p = 0.74). For patients who received second MDT, median follow-up from presentation of repeat OM was 2.6 years. Median PFS after first and second MDT were 15 months (95% CI 11-18) and 11 months (95% CI 7-17), respectively. At last follow-up, 22/44 patients (50%) were alive without polymetastatic recurrence. 3-year PMRFS and OS from presentation of repeat OM were 51% (95% CI 33-66%) and 66% (95% CI 47-79%), respectively.

CONCLUSION

Patients presenting with repeat OM after MDT may still have favorable 3-year PMRFS and OS, which may justify exploring aggressive local treatments in this subpopulation. Further randomized trials in this space are needed.

Prospective Longitudinal Assessment of Quality of Life after Stereotactic Ablative Radiotherapy for Oligometastases: Analysis of the Population-Based SABR-5 Phase II Trial

PURPOSE/OBJECTIVE(S)

To evaluate longitudinal patient-reported quality of life (QoL) in patients treated with stereotactic ablative radiotherapy (SABR) for oligometastases.

MATERIALS/METHODS

The SABR-5 trial was a population-based single-arm phase II study of SABR to up to 5 sites of oligometastases, conducted in 6 regional cancer centers in British Columbia from 2016 to 2020. Prospective QoL was measured using treatment site-specific QoL questionnaires at pre-treatment baseline and 3, 6, 9, 12, 15, 18, 21, 24, 30, and 36 months after treatment. Patients with bone metastases were assessed with the Brief Pain Inventory (BPI). Patients with liver, adrenal, and abdominopelvic lymph node metastases were assessed with the Functional Assessment of Chronic Illness Therapy-Abdominal Discomfort (FACIT-AD). Patients with lung and intrathoracic lymph node metastases were assessed with the Prospective Outcomes and Support Initiative (POSI) lung questionnaire. The two one-sided test procedure was used to assess equivalence between the worst QoL score and baseline score of individual patients. Mean QoL at all time points was used to determine the trajectory of QoL response after SABR. The proportion of patients with "stable," "improved," or "worsened" QoL was determined for all time points based on standard minimal clinically important differences (MCID; BPI worst pain = 2, BPI Functional Interference Score [FIS] = 0.5, FACIT-AD Trial Outcome Index [TOI] = 8, POSI = 3).

RESULTS

All enrolled patients with baseline QoL assessment and at least 1 follow-up assessment were analyzed (n = 135). On equivalence testing, patients' worst QoL scores were clinically different from baseline scores and met MCID (BPI worst pain mean difference: 1.8, 90% CI [1.19 to 2.42]; BPI FIS mean difference: 1.68, 90% CI [1.15 to 2.21]; FACIT-AD TOI mean difference: -8.76, 90% CI [-11.29 to -6.24]; POSI mean difference: -4.61, 90% CI [-6.09 to -3.14]). However, the mean FIS transiently worsened at 9, 18 and 21 months but eventually returned to stable levels. The mean FACIT and POSI scores also worsened at 36 months, albeit with a limited number of responses (n = 4 and 8, respectively). The majority of patients reported stable QoL at all time points (range: BPI worst pain 71-82%, BPI FIS 45-78%, FACIT-AD TOI 50-100%, POSI 25-73%). Clinically significant stability, worsening, and improvement were seen in 70%/13%/18% of patients at 3 months, 53%/28%/19% at 18 months and 63%/25%/13% at 36 months.

CONCLUSION

SABR in the oligometastatic setting can lead to transient decreases in QoL. However, most patients experienced stable QoL relative to pre-treatment levels on long-term follow-up. Further studies are needed to characterize patients at greatest risk for decreased QoL.

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.

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.

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.

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 following stereotactic ablative radiotherapy 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 stereotactic ablative radiotherapy (SABR). This study aimed to identify factors associated with early polymetastatic relapse (PMR).

METHODS AND MATERIALS

The XXX trial was a single arm phase II study conducted at all 6 regional cancer centres across XXX. 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, ECOG 0-2 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 XXX. A total of 16% of patients experienced PMR. Worse performance status (ECOG 1-2 vs 0; HR=2.01, p=0.018), non-prostate/breast histology (HR=3.64, p<0.001) and oligoprogression (HR=3.84, p<0.001) 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 OS were 0%, 53% (95% confidence interval [CI] 48 - 58), 77% (95% CI 73 - 81) and 93% (95% CI 90 - 96) in groups 1-4, respectively (p<0.001).

CONCLUSION

Four distinct risk groups for early PMR are identified, which differ significantly in PMR-free survival and overall survival. The group with all three 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.

Progression-free survival and local control following stereotactic ablative radiotherapy for up to 5 oligometastases: an analysis from the population-based phase II SABR-5 trial

PURPOSE

Despite increasing utilization of stereotactic ablative therapy (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 II XXX trial.

METHODS AND MATERIALS

The XXX trial was a single arm phase II study with the primary endpoint of toxicity, conducted at the 6 regional cancer centres across XXX, 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, ECOG 0-2 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 (IQR 18-36). Median PFS was 15 months (95% 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 (HR=1.09, p<0.001), declining performance status (HR=2.13, p<0.001), disease-free interval < 18 months (HR=1.52, p=0.003), four or more metastases at SABR (HR=1.48, p=0.048), initiation or change in systemic treatment (HR=0.50, p<0.001) and oligoprogression (HR=1.56, p=0.008) were significant independent predictors of PFS. Tumor diameter (SHR=1.28, p<0.001), colorectal histology (SHR=4.33, p=0.002) and "other" histology (SHR=3.90, p<0.001) were associated with worse local control.

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 on phase III trials, even outside the original 1-5 metachronous oligometastatic paradigm.

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.

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.

Identifying research questions for HIV, tuberculosis, tuberculosis-HIV, malaria, and neglected tropical diseases through the World Health Organization guideline development process: a retrospective analysis, 2008-2018

OBJECTIVES

World Health Organization (WHO) guidelines for health programmes and healthcare delivery are the foundation of its technical leadership in public health and essential to decision-making globally. A key function of guideline development is to identify areas in which further evidence is needed because filling these gaps will lead to future improvements in population health. The objective of this study was to examine the knowledge gaps and research questions for addressing those gaps generated through the WHO guideline development process, with the goal of informing future strategies for improving and strengthening the guideline development process.

STUDY DESIGN

We did a systematic, retrospective analysis of research questions identified in the published guidelines.

METHODS

We analyzed guidelines published between January 1, 2008, and December 31, 2018, by the Communicable Diseases Cluster in five disease areas: tuberculosis (TB), HIV, malaria, TB-HIV, and neglected tropical diseases (NTDs). Research questions were extracted independently by two researchers. We analyzed the distribution of research questions by disease and by topic category and did a qualitative assessment of optimum practice for research question generation during the guideline development process.

RESULTS

A total of 48 guidelines were included: 26 on HIV, 1 on malaria, 11 on TB, 5 on TB/HIV, and 5 on NTDs. Overall, 36 (75%) guidelines encompassed a total of 360 explicit research questions; the remainder did not contain specific research questions. The number of research questions that focused on TB was 49, TB/HIV was 38, HIV was 250, and NTDs was 23. The number of research questions that focused on diagnosis was 43 (11.9%) of 360, prevention was 62 (17.2%), treatment was 103 (28.6%), good practice was 12 (3.3%), service delivery was 86 (23.8%), and other areas was 54 (15%). Research questions were often not formulated in a specific or actionable way and were hard to identify in the guideline. Examples of good practice identified by the review team involved the generation of specific and narrowly defined research questions, with accompanying recommendations for appropriate study design.

CONCLUSIONS

The WHO must strengthen its approach to identifying and presenting research questions during the guideline development process. Ensuring access to research questions is a key next step in adding value to the guideline development process.

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.

Technical Note: Cardiac synchronized volumetric modulated arc therapy for stereotactic arrhythmia radioablation - Proof of principle

PURPOSE

Ventricular tachycardia (VT) is a rapid, abnormal heart rhythm that can lead to sudden cardiac death. Current treatment options include antiarrhythmic drug therapy and catheter ablation, both of which have only modest efficacy and have potential complications. Cardiac radiosurgery has the potential to be a noninvasive and efficient treatment option for VT. Cardiac motion, however, must be accounted for to ensure accurate dose delivery to the target region. Cardiac synchronized volumetric modulated arc therapy (CSVMAT) aims to minimize the dose delivered to normal tissues by synchronizing beam delivery with a cardiac signal, irradiating only during the quiescent intervals of the cardiac cycle (when heart motion is minimal) and adjusting the beam delivery speed in response to heart rate changes.

METHODS

A CSVMAT plan was adapted from a conventional VMAT plan and delivered on a Varian TrueBeam linear accelerator. The original VMAT plan was divided into three interleaved CSVMAT phases, each consisting of alternating beam-on and beam-off segments synchronized to a sample heart rate. Trajectory log files were collected for the original VMAT and CSVMAT deliveries and the dose distributions were measured with Gafchromic EBT-XD film.

RESULTS

Analysis of the trajectory log files showed successful synchronization with the sample cardiac signal. Film analysis comparing the original VMAT and CSVMAT dose distributions returned a gamma passing rate of 99.14% (2%/2 mm tolerance).

CONCLUSIONS

The film results indicated excellent agreement between the dose distributions of the original and cardiac synchronized beam deliveries. This study demonstrates a proof of principle cardiac synchronization strategy for precise radiation treatment plan delivery and adjustment to a variable heart rate. The cardiac synchronized technique may be advantageous in radioablation for VT.

Stereotactic Ablative Radiotherapy for the Comprehensive Treatment of Oligometastatic Cancers: Long-Term Results of the SABR-COMET Phase II Randomized Trial

PURPOSE

The oligometastatic paradigm hypothesizes that patients with a limited number of metastases may achieve long-term disease control, or even cure, if all sites of disease can be ablated. However, long-term randomized data that test this paradigm are lacking.

METHODS

< .20 indicates a positive trial). Secondary end points included progression-free survival (PFS), toxicity, and quality of life (QOL). Herein, we present long-term outcomes from the trial.

RESULTS

= .001). There were no new grade 2-5 adverse events and no differences in QOL between arms.

CONCLUSION

With extended follow-up, the impact of SABR on OS was larger in magnitude than in the initial analysis and durable over time. There were no new safety signals, and SABR had no detrimental impact on QOL.

SUPR-3D: A randomized phase iii trial comparing simple unplanned palliative radiotherapy versus 3d conformal radiotherapy for patients with bone metastases: study protocol

Background

Bone metastases in the lower spine and pelvis are effectively palliated with radiotherapy (RT), though this can come with side effects such as radiation induced nausea and vomiting (RINV). We hypothesize that high rates of RINV occur in part because of the widespread use of inexpensive simple unplanned palliative radiotherapy (SUPR), over more complex and resource intensive 3D conformal RT, such as volumetric modulated arc therapy (VMAT).

Methods

This is a randomized, multi-centre phase III trial of SUPR versus VMAT. We will accrue 250 patients to assess the difference in patient-reported RINV. This study is powered to detect a difference in quality of life between patients treated with VMAT vs. SUPR.

Discussion

This trial will determine if VMAT reduces early toxicity compared to SUPR and may provide justification for this more resource-intensive and costly form of RT.

Trial registration

Clinicaltrials.gov identifier: NCT03694015.

Date of registration: October 3, 2018.

Provincial development of a patient-reported outcome initiative to guide patient care, quality improvement, and research

The BC Cancer Agency Radiotherapy (RT) program started the Prospective Outcomes and Support Initiative (POSI) at all six centres to utilize patient-reported outcomes for immediate clinical care, quality improvement, and research. Patient-reported outcomes were collected at time of computed tomography simulation via tablet and 2 to 4 weeks post-RT via either tablet or over the phone by a registered nurse. From 2013 to 2016, patients were approached on 20,150 attempts by POSI for patients treated with RT for bone metastases (52%), brain metastases (11%), lung cancer (17%), gynecological cancer (16%), head and neck cancer (2%), and other pilots (2%). The accrual rate for all encounters was 85% (n = 17,101), with the accrual rate varying between the lowest and the highest accruing centre from 78% to 89% ( P < .001) and varying by tumour site ( P < .001). Using the POSI database, we have performed research and quality improvement initiatives that have changed practice.