Modeling the COVID Pandemic: Do Delays in Surgery Justify Using Stereotactic Radiation to Treat Low-Risk Early Stage Non-Small Cell Lung Cancer?

INTRODUCTION: It was suggested that stereotactic radiation (SBRT) is an "alternative if no surgical capacity is available" for non-small cell lung cancer (NSCLC) care during the COVID-19 pandemic. The purpose of this study was to compare the oncologic outcomes of delayed surgical resection and early SBRT among operable patients with early stage lung cancer. METHODS: The National Cancer Database was queried for patients with cT1aN0M0 NSCLC who underwent surgery or SBRT (2010-2016) with no comorbidity. Patients with any comorbidities or age >80 were excluded. The outcome of interest was overall survival. Delays in surgical care were modeled using different times from diagnosis to surgery. A 1:1 propensity match was performed and survival was analyzed using multivariable Cox regression. RESULTS: Of 6720 healthy cT1aN0M0 NSCLC patients, 6008 (89.4%) received surgery and 712 (10.6%) received SBRT. Among surgery patients, time to surgery >30 d was associated with inferior survival (HR > 1.4, P ≤ 0.013) compared with patients receiving surgery ≤14 d. Relative to SBRT, surgery demonstrated superior survival at all time points evaluated: 0-30 d, 31-60 d, 61-90 d, and >90 d (all P < 0.001). Among a propensity-matched cohort of 256 pairs of patients, delayed surgery (>90 d) remained association with better overall survival relative to early SBRT (5-year survival 76.9% versus 32.3%, HR = 0.266, P < 0.001). CONCLUSIONS: Although longer time to surgery is associated with inferior survival among surgery patients, delayed surgery is superior to early SBRT. Surgical resection should remain the standard of care to treat operable early stage lung cancer despite delays imposed by the COVID-19 pandemic.

Abdominopelvic MR to CT registration using a synthetic CT intermediate.

Accurate coregistration of computed tomography (CT) and magnetic resonance (MR) imaging can provide clinically relevant and complementary information and can serve to facilitate multiple clinical tasks including surgical and radiation treatment planning, and generating a virtual Positron Emission Tomography (PET)/MR for the sites that do not have a PET/MR system available. Despite the long-standing interest in multimodality co-registration, a robust, routine clinical solution remains an unmet need. Part of the challenge may be the use of mutual information (MI) maximization and local phase difference (LPD) as similarity metrics, which have limited robustness, efficiency, and are difficult to optimize. Accordingly, we propose registering MR to CT by mapping the MR to a synthetic CT intermediate (sCT) and further using it in a sCT-CT deformable image registration (DIR) that minimizes the sum of squared differences. The resultant deformation field of a sCT-CT DIR is applied to the MRI to register it with the CT. Twenty-five sets of abdominopelvic imaging data are used for evaluation. The proposed method is compared to standard MI- and LPD-based methods, and the multimodality DIR provided by a state of the art, commercially available FDA-cleared clinical software package. The results are compared using global similarity metrics, Modified Hausdorff Distance, and Dice Similarity Index on six structures. Further, four physicians visually assessed and scored registered images for their registration accuracy. As evident from both quantitative and qualitative evaluation, the proposed method achieved registration accuracy superior to LPD- and MI-based methods and can refine the results of the commercial package DIR when using its results as a starting point. Supported by these, this manuscript concludes the proposed registration method is more robust, accurate, and efficient than the MI- and LPD-based methods.

On the Frontiers of Breast Cancer Diagnosis and Treatment: Current and Future Directions in a Rapidly Changing Field.

Breast cancer (BCa) represents a medically heterogeneous group of malignancies, with differing biological and genetic makeups [...].

Harmonized Outcome Measures for Use in Non-Small Cell Lung Cancer Patient Registries and Clinical Practice.

BACKGROUND: Lung cancer is the leading cause of cancer-related death in the United States and globally, and many questions exist about treatment options. Harmonizing data across registries and other data collection efforts would yield a robust data infrastructure to help address many research questions. The purpose of this project was to develop a minimum set of patient and clinician relevant harmonized outcome measures that can be collected in non-small cell lung cancer (NSCLC) patient registries and clinical practice. METHODS: Seventeen lung cancer registries and related efforts were identified and invited to submit outcome measures. Representatives from medical specialty societies, government agencies, health systems, health information technology groups, patient advocacy organizations, and industry formed a stakeholder panel to categorize the measures and harmonize definitions using the Agency for Healthcare Research and Quality's supported Outcome Measures Framework (OMF). RESULTS: The panel reviewed 66 outcome measures and identified a minimum set of 8 broadly relevant measures in the OMF categories of patient survival, clinical response, events of interest, and resource utilization. The panel harmonized definitions for the 8 measures through in-person and virtual meetings. The panel did not reach consensus on 1 specific validated instrument for capturing patient-reported outcomes. The minimum set of harmonized outcome measures is broadly relevant to clinicians and patients and feasible to capture across NSCLC disease stages and treatment pathways. A pilot test of these measures would be useful to document the burden and value of the measures for research and in clinical practice. CONCLUSIONS: By collecting the harmonized measures consistently, registries and other data collection systems could contribute to the development research infrastructure and learning health systems to support new research and improve patient outcomes.

Role of radiation in extensive stage small cell lung cancer: a National Cancer Database registry analysis.

The role of prophylactic cranial irradiation (PCI) and thoracic radiation therapy (TRT) in extensive-stage small cell lung cancer remains controversial. The authors examined the National Cancer Database and identified patients with extensive-stage small cell lung cancer with no brain metastasis. Patients were excluded if they died 30 days from diagnosis, did not receive polychemotherapy, had other palliative radiation or had missing information. A propensity score-matched analysis was also performed. A total of 21,019 patients were identified. The majority of patients did not receive radiation (69%), whereas 10% received PCI and 21% received TRT. The addition of PCI and TRT improved median survival and survival at 1 and 2 years (p ≤ 0.05). The propensity score-matched analysis confirmed the same overall survival benefit with both PCI and TRT. This registry-based analysis of >1500 accredited cancer programs shows that PCI and TRT are not commonly utilized for extensive-stage small cell lung cancer patients who are treated with multiagent chemotherapy. The addition of PCI and TRT significantly improves overall survival in this otherwise poor prognostic group. Further research is needed to confirm the role of PCI and TRT, especially in the era of improved systemic therapy.

Lay abstract The role of radiation therapy in patients with metastatic small cell lung cancer remains controversial. The authors examined the National Cancer Database and identified patients with metastatic small cell lung cancer without brain metastasis. Patients were excluded if they died 30 days from diagnosis, did not receive multiagent chemotherapy, had other palliative radiation or had missing information regarding treatment. A total of 21,019 patients were identified. The majority of patients did not receive radiation (69%), whereas 10% received radiation to the brain and 21% received radiation to their lungs. The addition of brain and lung radiation therapy improved median survival and survival at 1 and 2 years. The addition of prophylactic cranial irradiation and thoracic radiation therapy improves survival in extensive-stage small cell lung cancer. Future research is needed to evaluate the role of radiation in the era of chemoimmunotherapy.

A simple matrix to predict treatment success and long-term survival among patients undergoing pancreatectomy.

BACKGROUND: A more accurate measure of long-term survival among patients who have undergone a successful resection for pancreatic adenocarcinoma may be computed by accounting for time already survived during the initial treatment window. METHODS: Patients diagnosed with pancreatic adenocarcinoma, from 2004 through 2013, were identified from the American College of Surgeons National Cancer Database (NCDB). A risk-stratification matrix was constructed including age, histopathologic factors and the use of adjuvant therapy, given successful treatment and survival at 3-month following diagnosis. RESULTS: A total of 25,897 patients (50% male, 53% >65 years of age) presented with stage I-III pancreatic cancer. The majority of patients had tumors >2 cm size (82%), grade I/II (65%), lymphatic invasion (LI) (66%), and negative margins (76%). A survival advantage for adjuvant therapy was observed among all patients, independent of their risk-profile. For example, a patient ≤65 years of age, with early stage cancer (size ≤2 cm, grade I/II, -ve LI, -ve margins) who received adjuvant therapy had a 62% probability of being alive beyond three years (95%CI = 59%-66%). In contrast, the survival probability decreased to 53% (95%CI = 59%-66%) without adjuvant therapy. CONCLUSIONS: These results provide surgeons and patients with more accurate information regarding long-term survival, as well as the benefit of opting for adjuvant therapy after successful pancreatic surgery.

Perioperative chemotherapy versus postoperative chemoradiotherapy in patients with resectable gastric/gastroesophageal junction adenocarcinomas: A survival analysis of 5058 patients.

BACKGROUND: Both perioperative chemotherapy (PECT) and postoperative chemoradiotherapy (POCRT) have a significant survival advantage over surgery alone for the treatment of patients with gastric cancer. However, to the best of our knowledge, these regimens have not been compared in a randomized clinical trial. The purpose of the current observational study was to compare overall survival among patients receiving PECT versus POCRT for the treatment of gastric/gastroesophageal junction (GEJ) adenocarcinomas. METHODS: Patients with resected clinical American Joint Committee on Cancer TNM stage II or III adenocarcinomas of the stomach or GEJ from 2004 through 2013 were identified utilizing the National Cancer Data Base. Hazard ratios (HRs), 95% confidence intervals, and P values were computed using a Cox proportional hazards procedure. Multivariable models were adjusted for treatment regimen, age, race, ethnicity, tumor size, TNM stage, Charlson comorbidity index, and tumor grade. RESULTS: Patients receiving PECT had a 72% survival advantage compared with those treated with POCRT (5058 patients; HR, 0.58 [adjusted P<.0001]). The 5-year actuarial survival rate for PECT was 44% compared with 38% for POCRT. A statistically significant survival advantage for PECT also was observed when the analysis was stratified by clinical stage of disease (stage II [3192 patients]: adjusted HR, 0.79 [P = .041]; and stage III [1866 patients]: adjusted HR, 0.49 [P<.0001]). This benefit was greatest among patients with lymph node-positive disease who converted to lymph node-negative status with PECT. CONCLUSIONS: In this large series of patients with stage II/III resected gastric/GEJ adenocarcinomas from >1500 American College of Surgeons Commission on Cancer-accredited facilities, patients receiving PECT were shown to survive longer than those receiving POCRT. Cancer 2017;123:2909-17. © 2017 American Cancer Society.

Local therapy for triple-negative breast cancer: a comprehensive review.

Owing to its aggressive course, triple-negative breast cancer remains an important clinical issue of current interest compared with hormone-receptor positive subtypes. Recent research has focused on determining the optimal local therapy (breast conversation therapy vs mastectomy) for this cancer subtype. In this overview, we examine outcomes based on immunohistochemistry, gene expression profiles, type of local therapy and in the era of neoadjuvant chemotherapy. Based on multiple observational reports risk for locoregional recurrence appears to be similar to reported outcomes in other subtypes. However, distant recurrence continues to be a significant concern for triple-negative breast cancer, indicating the need for better systemic therapies. To date, insufficient evidence exists to determine whether breast conserving therapy or mastectomy results in superior outcomes.

Prognostic potential of neutrophil-to-lymphocyte ratio and lymphocyte nadir in stage III non-small-cell lung cancer.

AIM: Studies have shown increased pretreatment neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios to be predictive of survival in various cancers. Our aim was to evaluate the prognostic role of such inflammatory markers in non-small-cell lung cancer (NSCLC). METHODS: One hundred and sixty-three patients with stage III NSCLC who received definitive treatment were included. Survival analysis was performed using Kaplan-Meier method. Hazard ratios for overall and recurrence-free survival were estimated using Cox proportional hazards model. RESULTS: Both neutrophil-to-lymphocyte >Q75 (4.5) and lymphocyte nadir values

A multinational report of technical factors on stereotactic body radiotherapy for oligometastases.

AIM: Oligometastatic cancer is being increasingly managed with aggressive local therapy using stereotactic body radiation therapy (SBRT). However, few guidelines exist. We summarize the results of an international survey reviewing technical factors for extracranial SBRT for oligometastatic disease to guide safe management. MATERIALS & METHODS: Seven high-volume centers contributed. Levels of agreement were categorized as strong (6-7 common responses), moderate (4-5), low (2-3) or no agreement. RESULTS & CONCLUSION: We present the results of a multi-national and multi-institutional survey of technical factors of SBRT for extracranial oligometastases. Key methods including target delineation, prescription doses, normal tissue constraints, imaging and set-up for safe implementation and practice of SBRT for oligometastasis have been identified. This manuscript will serve as a foundation for future clinical evaluations.

Current topics in the multimodality treatment of locally advanced rectal cancer.

The multimodality approach to the treatment of locally advanced rectal cancer has evolved to include neoadjuvant radiotherapy with or without concurrent chemotherapy, total mesorectal excision and adjuvant fluoropyrimidine-based chemotherapy. Though this broad strategy has yielded improvements in local control compared with historical data, overall survival remains largely unchanged. Current investigations focus on improving patient selection through new imaging modalities, improving surgical techniques, incorporating more aggressive systemic treatment regimens and the selective use of radiation. Here, we review emerging data regarding newer staging techniques, neoadjuvant chemotherapy, optimal timing of surgery, selective use of radiation and nonoperative approaches to the management of locally advanced rectal cancers.

Adjuvant and neoadjuvant options in resectable gastric cancer: is there an optimal treatment approach?

Gastric cancer is one of the most prevalent and deadliest forms of cancer worldwide. Even though neoadjuvant, perioperative, and adjuvant chemotherapy and/or radiation therapy may improve outcomes compared with surgery alone, the optimal combination of treatment modalities remains controversial. While European and North American trials established perioperative chemotherapy and adjuvant chemoradiation regimens for gastric cancer, Asian countries have focused on the use of adjuvant chemotherapy. This review summarizes results from contemporary randomized controlled trials and meta-analyses to elucidate the relative merits of each treatment approach.

Chest wall and rib irradiation and toxicities of early-stage lung cancer patients treated with CyberKnife stereotactic body radiotherapy.

AIM: The aim of the study is to evaluate the chest wall and rib toxicities in primary lung cancer patients treated with CyberKnife-based stereotactic body radiotherapy. MATERIALS & METHODS: In this study, data were collected from the 118 patients, of which 25 patients who had longer follow-up (mean: 21.9 months) were considered. Studied parameters were maximum point dose, doses to 1-100 cm(3) of chest wall and 1-10 cm(3) of ribs. RESULTS: Three patients developed chest wall pain (grade I). 25 studied patients, on average, received 27.7 Gy to 30 cm(3) of chest wall and 50.4 Gy to 1 cm(3) of rib. Nine patients had more than 30 Gy dose to 30 cm(3) of chest wall. No rib bone fracture was found. CONCLUSION: No correlations of chest wall pain and volume of irradiation were found.

Emerging applications of stereotactic body radiotherapy.

Stereotactic body radiotherapy (SBRT) has been used extensively in patients with lung, liver and spinal tumors, and the treatment outcomes are very favorable. For certain conditions such as medically inoperable stage I non-small-cell lung cancer, liver and lung oligometastases, primary liver cancer and spinal metastases, SBRT is regarded as one of the standard therapies. In the recent years, the use of SBRT has been extended to other disease conditions and sites such as recurrent head and neck cancer, renal cell carcinoma, prostate cancer, adrenal metastasis, pancreatic cancer, gynecological malignancies, spinal cord compression, breast cancer, and stage II-III non-small-cell lung cancer. Preliminary data in the literature show promising results but the follow-up intervals are short for most studies. This paper will provide an overview of these emerging applications.

Pretreatment and Posttreatment Tumor Metabolic Activity Assessed by FDG-PET/CT as Predictors of Tumor Recurrence and Survival Outcomes in Early-Stage Non-Small Cell Lung Cancer Treated With Stereotactic Body Radiation Therapy.

Purpose: Stereotactic body radiation therapy (SBRT) is considered the standard of care for medically inoperable early-stage non-small cell lung cancer. There is mixed evidence on the prognostic significance of tumor metabolic activity assessed by positron emission tomography combined with computed tomography (PET/CT) using F-18 fluorodeoxyglucose (FDG). The objectives of this study were to evaluate the maximum standardized uptake value (SUVmax) pretreatment and at 3 and 6 months after SBRT for prediction of tumor control and survival outcomes. Methods and Materials: Consecutive patients from a single institution with T12N0M0 non-small cell lung cancer receiving primary treatment with SBRT with pretreatment FDG-PET/CT (n = 163) and follow-up FDG-PET/CT at 3 or 6 months (n = 71) were included. Receiver operator characteristic analysis was performed to dichotomize variables for Kaplan-Meier survival analysis. Multivariate analysis was performed with Cox proportional hazards regression. Results: Median follow-up was 19 months. For the whole cohort, 1-year and 2-year local control, progression-free survival (PFS), and overall survival (OS) were 95.0% and 80.3%, 87.1% and 75.4%, and 67.0% and 49.6% respectively. The following pre-SBRT SUVmax cutoffs were significant: SUV > 4.0 for distant failure-free survival (adjusted hazard ratio [aHR], 3.33, P = .006), >12.3 for PFS (aHR, 2.80, P = .011), and >12.6 for OS (aHR, 3.00, P = .003). SUVmax decreases of at least 45% at 3 months (aHR, 0.15, P = .018), and 53% at 6 months (aHR, 0.12, P = .046) were associated with improved local failure-free survival. Conclusions: Pre-SBRT SUVmax cutoffs can predict distant failure, PFS, and OS. At both 3 and 6 months after SBRT, cutoffs for percentage change in SUVmax can potentially stratify risk of local recurrence.

Outcomes of initial therapy for synchronous brain metastases from small cell lung cancer: a single-institution retrospective analysis.

Small cell lung cancer (SCLC) has a propensity for brain metastases, which is associated with poor prognosis. We sought to determine predictors of overall survival (OS) and brain progression-free survival (bPFS) in SCLC patients with synchronous brain metastases at the time of initial SCLC diagnosis. A total of 107 SCLC patients with synchronous brain metastases treated at a single institution were included in this retrospective analysis. These patients had brain lesions present on initial staging imaging. Survival was estimated using the Kaplan-Meier method with log-rank test. Factors predictive of OS and bPFS were analyzed using Cox proportional hazards regression model. Median OS for the entire cohort was 9 months (interquartile range, 4.2-13.8 months) and median bPFS was 7.3 months (interquartile range, 3.5-11.1 months). OS was 30.3% at 1 year and 14.4% at 2 years, while bPFS was 22.0% at 1 year and 6.9% at 2 years. The median number of brain lesions at diagnosis was 3 (interquartile range, 2-8), and the median size of the largest metastasis was 2.0 cm (interquartile range, 1.0-3.3 cm). Increased number of brain lesions was significantly associated with decreased OS. Patients who received both chemotherapy and whole brain radiation therapy (WBRT) had improved OS (P=0.02) and bPFS (P=0.005) compared to those who had either chemotherapy or WBRT alone. There was no significant difference in OS or bPFS depending on the sequence of therapy or the dose of WBRT. Thirteen patients underwent upfront brain metastasis resection, which was associated with improved OS (P=0.02) but not bPFS (P=0.09) compared to those who did not have surgery. The combination of chemotherapy and WBRT was associated with improved OS and bPFS compared to either modality alone. Upfront brain metastasis resection was associated with improved OS but not bPFS compared to those who did not have surgery.

Invasive Nodal Staging via Endobronchial Ultrasound and Outcome in Patients Treated with Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer - Results from a Single Institution Study.

INTRODUCTION: Stereotactic body radiation therapy (SBRT) is an effective treatment for medically inoperable early-stage non-small cell lung cancer (NSCLC). The prognostic value of invasive nodal staging (INS) for patients undergoing SRBT has not been studied extensively. Herein, we report the impact of INS in addition to 18F-FDG-PET on treatment outcome for patients with NSCLC undergoing SBRT. MATERIALS AND METHODS: Patients with stage I/ II NSCLC who underwent SBRT were included with IRB approval. Clinical, dosimetric, and radiological data were obtained. Overall survival (OS), regional recurrence free survival (RRFS), local recurrence free survival (LRFS), and distant recurrence free survival (DRFS) were analyzed using Kaplan Meyer method. Univariable analysis (UVA) and multivariable analysis (MVA) were performed to assess the relationship between the variables and the outcomes. RESULTS: A total of 376 patients were included in the analysis. Median follow up was 43 months (IQ 32.6-45.8). Median OS, LRFS, RRFS, DRFS were 40, 32, 32, 33 months, respectively. The 5-year local, regional, and distant failure rates were 13.4%, 23.5% and 25.3%, respectively. The 1-year, 3-year and 5-year OS were 83.8%, 55.6%, and 36.3%, respectively. On MVA, INS was not a predictor of either improved overall or any recurrence free survival endpoints while larger tumor size, age, and adjusted Charleston co-morbidity index (aCCI) were significant for inferior LRFS, RRFS, and DRFS. CONCLUSION: Invasive nodal staging did not improve overall or recurrence free survival among patients with early-stage NSCLC treated with SBRT whereas older age, aCCI, and larger tumor size were significant predictors of LRFS, RRFS, and DRFS.

The relation of race and type of health insurance to long-term risk of mortality among lung cancer patients in rural Eastern North Carolina.

BACKGROUND: Black patients with lung cancer have a higher mortality rate than do their white counterparts. Differences in insurance coverage, demographic characteristics, and treatment profiles may explain this disparity. The purpose of this study was to compare the longterm risk of mortality of black lung cancer patients with that of white lung cancer patients, by insurance type. METHODS: Patients who were diagnosed with lung cancer in Eastern North Carolina and treated at the Leo Jenkins Cancer Center between 2001 and 2010 were included in this study. A Cox regression model was used to compare the risk of mortality of black patients with that of white patients. RESULTS: A total of 2,351 lung cancer patients (717 black and 1,634 white) were treated at the Leo Jenkins Cancer Center during the study period. Independent of age and sex, black patients with lung cancer were observed to die sooner than their white counterparts (hazard ratio = 1.2; 95% confidence interval, 1.04-1.3; P = .0070). However, this difference was not statistically significant after controlling for and stratifying by insurance type. LIMITATIONS: Residual confounding and the misclassification of some variables could have biased estimated study effects. CONCLUSION: The racial disparity in lung cancer mortality observed in Eastern North Carolina is no longer apparent after health insurance type is accounted for.

The Impact of Prophylactic Cranial Irradiation and Consolidative Thoracic Radiation Therapy for Extensive Stage Small-Cell Lung Cancer in the Transition to the Chemo-Immunotherapy Era: A Single Institution Series.

INTRODUCTION: Extensive-stage small-cell lung cancer (ES-SCLC) continues to have poor survival due to its aggressive behavior, despite improvements with incorporation of immunotherapy with standard chemotherapy. Controversy exists regarding the role of consolidative thoracic radiation therapy (TRT) and prophylactic cranial irradiation (PCI) in ES-SCLC due to high recurrence rates. We report our institutional result of the benefit of PCI and TRT in ES-SCLC. METHODS: Patients with ES-SCLC without intracranial metastasis at diagnosis (N = 163) were included. All patients completed systemic therapy with or without immunotherapy based on time of standard of care. Cohorts were divided by systemic therapy use and further subdivided by treatment with PCI and TRT. Overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan-Meier method with log-rank test for comparison. The effects of TRT and PCI were estimated by multivariable (MVA) Cox regression. RESULTS: Seventy-four patients (45.4%) received TRT, and 33.1% (n = 54) received PCI. The median follow-up was 11 months (3-85 months). PCI improved median OS to 15 months from 10 months, P = .02) and median PFS to 8.5 months from 5 months (P = .02) which remained significant on MVA, P = .02 and P = .02, respectively. TRT improved OS on UVA (P = 0.002) but was not significant on MVA. TRT did not improve PFS. CONCLUSION: This study including chemotherapy and chemo-immunotherapy suggests improved outcomes with addition of PCI in patients with ES-SCLC while TRT did not show benefit to either OS or PFS. A future trial is needed to evaluate the role of TRT and PCI in the era of chemo-immunotherapy.

The impact of local control on widespread progression and survival in oligometastasis-directed SBRT: Results from a large international database.

PURPOSE: We investigated the impact of local control (LC) on widespread progression (WSP) and overall survival (OS) in patients treated to all extracranial oligometastases (OMs) at presentation to SBRT in this retrospective review across 6 international centers. MATERIALS/METHODS: Relationships between LC status of SBRT-directed OMs and OS and WSP (>5 new active/untreated lesions) were explored using Cox and Fine-Gray regression models, adjusting for radioresistant histology and pre-SBRT systemic therapy receipt. The association between LC and dosimetric predictors was analyzed with competing risk regression using death as a competing risk and across a wide range of simulated α/ßratios. RESULTS: In total, 1700 OMs in 1033 patients were analyzed, with 25.2% NSCLC, 22.7% colorectal, 12.8% prostate, and 8.1% breast histology. Patients who failed locally in any SBRT-directed OM within 6 mo were at 3.6-fold higher risk of death and 2.7-fold higher risk of WSP compared to those who remained locally-controlled (p < 0.001). Similar associations existed for each duration of LC investigated through 3 yrs post-SBRT. There was no significant difference in risk of WSP or death between patients who failed in a subset of SBRT-treated lesions vs. patients who failed in all lesions. Minimum dose (Dmin) to the GTV/ITV was most predictive of LC when compared to prescription dose, PTV Dmin, and PTV Dmax. Sensitivity analysis for achieving 1-yr LC > 95% found thresholds of 41.2 Gy and 55.2 Gy in 5 fractions for smaller (< 27.7 cc) and larger radioresistant lesions, respectively. CONCLUSION: This large multinational cohort suggests that the duration of LC following OM-directed SBRT strongly correlates with WSP and OS.