Stereotactic body radiotherapy for early-stage non-small cell lung cancer: clinical outcomes from a National Patient Registry

Treatment outcomes of passive scattering proton beam therapy for stage I non-small cell lung cancer

INTRODUCTION

To investigate the treatment outcomes of passive scattering proton beam therapy using stereotactic ablative radiotherapy (SABR) or hypofractionated radiation therapy (RT) for inoperable patients or those who refused surgery for stage I non-small cell lung cancer (NSCLC).

METHODS

From January 2016 to December 2019, we retrospectively analyzed 42 patients with stage I NSCLC treated with proton beam therapy. The initially intended dose regimen was 60 cobalt Gray equivalents (CGE) in 4 fractions; however, sequentially modified dose regimens were used when the dose-volume constraints could not be met. The median total dose was 50 CGE (range 50-70 CGE), while the corresponding median biologically effective dose using [Formula: see text]= 10 (BED₁₀) was 112.5 CGE (range 96-150 CGE).

RESULTS

The median follow-up time was 40 months (interquartile range 32-48 months). Among the 42 treated patients, 33 had pathologically proven cancers of which most were adenocarcinoma (n = 21, 64%). The 3-year overall survival rate was 71.8%. The estimated rates of local control and progression free survival at 3 years were 91.5% and 66.9%, respectively. Thirteen patients experienced disease progression consisting of three local, six regional, and nine distant failures. No grade 4 or 5 toxicities were observed.

CONCLUSION

Passive scattering proton beam therapy for stage I NSCLC using SABR or hypofractionated RT was safe and showed high LC rates.

Comparison of technical success and safety of transbronchial versus percutaneous CT-guided fiducial placement for SBRT of lung tumors

OBJECTIVE

To evaluate the technical success and safety of transbronchial (bronchoscopic) fiducial placement compared to percutaneous CT-guided fiducial placement for stereotactic body radiotherapy (SBRT) of lung tumors.

MATERIALS AND METHODS

This IRB-approved, HIPAA-compliant retrospective study was performed at a single tertiary institution. Consecutive patients undergoing lung fiducial placement for purposes of guiding SBRT (CyberKnife®, Accuray, Inc.) between September 2005 to January 2013 were included in the study. Fiducial seeds were placed percutaneously with CT guidance or transbronchially with bronchoscopic guidance. We compared procedure-related complications (pneumothorax, chest tube placement), technical success (defined as implantation enabling adequate treatment planning with CT simulation) and migration rate. The need for repeat procedures and their mode was noted. Statistical analysis was performed using Fisher exact and Chi square probability tests.

RESULTS

Two hundred and forty-four patients with lung tumors and 272 fiducial seed placements were included in the study. Two hundred and twenty-one of the 272 (81.2%) fiducial markers were placed percutaneously and 51/272 (18.8%) were placed transbronchially. Pneumothorax was seen in 73/221 (33%) of percutaneously-placed fiducials and in 4/51 (7.8%) of transbronchial placements (p<0.001). No significant difference was seen in the rate of chest tube placement between the two groups: 20/221 (9%) of percutaneously placed fiducials and 2/51 (3.9%) of transbronchially placed fiducials (p=0.39). Fifteen of the 51 (29%) of fiducial placements with transbronchial approach were unsuccessful, as discovered at radiotherapy planning session, and required a repeat procedure. Nine of the 15 (60%) of repeat procedures were performed percutaneously, 5/15 (33%) were placed during repeat bronchoscopy, and 1/15 (7%) was placed at transesophageal endoscopic ultrasound. No repeat fiducial placements were required for patients who had the fiducials placed percutaneously (p<0.001), with a technical success rate of 100%.

CONCLUSION

Transbronchial fiducial marker placement has a significantly higher rate of failed seed placements requiring repeat procedures in comparison to percutaneous placement. Complication rate of pneumothorax requiring chest drain placement is similar between the two approaches.

Interobserver Variability in the Computed Tomography Assessment of Pulmonary Injury and Tumor Recurrence After Stereotactic Body Radiotherapy

PURPOSE

To evaluate the interobserver agreement of chest computed tomography (CT) findings in the diagnosis of expected changes and local recurrence after stereotactic body radiation therapy (SBRT) in patients with early-stage lung cancer or a single pulmonary metastasis.

MATERIALS AND METHODS

A total of 54 patients with early-stage lung cancer or pulmonary metastasis who were treated with SBRT from 2007 to 2015 were included. The exclusion criteria were patients who presented with pulmonary infection during follow-up and patients who underwent a single CT during follow-up. The imaging features on CT were assessed by 3 blinded radiologists at the following 2 time points after SBRT: (a) early follow-up and (b) late follow-up (≥6 mo). The radiologists classified the findings as expected changes after SBRT or recurrence. Interobserver agreement was assessed by kappa and Wilcoxon statistics.

RESULTS

A total of 13 women and 41 men with a mean age of 75.3 (±8.9) years were selected. The total and per fraction SBRT doses were 54 Gy (interquartile range: 45 to 54) and 18 Gy (interquartile range: 15 to 18), respectively. All expected changes and findings suggestive of recurrence had an almost perfect agreement (κ>0.85) among readers, except for diffuse consolidation in the early period (κ=0.65).

CONCLUSION

CT findings demonstrate high interobserver agreement for expected changes and for findings indicating recurrence after SBRT.

Extending hypofractionated stereotactic body radiotherapy to tumours larger than 70cc - effects and side effects

BACKGROUND AND PURPOSE

Stereotactic body radiotherapy (SBRT) for tumours ≥5 cm is poorly studied and its utility and feasibility is uncertain. We here report the Karolinska experience of SBRT in this setting.

MATERIAL AND METHODS

All patients had a gross tumour volume (GTV) ≥70 cc, a prescribed physical dose of at least 40 Gy and received treatment between 1995-2012.

RESULTS

We included 164 patients with 175 tumours located in the thorax (n = 86), the liver (n = 27) and the abdomen (n = 62) and treated with a median prescribed dose (BED_α/β 10Gy) of 80 Gy (71.4-113). One- and 2- year local control rates were 82% and 61%. In multivariate analyses, minimum dose to the GTV and histological subtype were associated with local control. Renal cell carcinoma (RCC) histology showed the most favourable local control - 94% at 2 years for all histologies. Thirty-seven patients experienced grade 3-5 toxicity most likely related to SBRT. Seven of the ten patients with grade 5 toxicity, had a centrally located tumour in the thorax.

CONCLUSION

SBRT of tumours >5 cm in diameter may be an option for peripherally located lung and abdominal tumours. Histological origin and tumour location should be considered before treatment.

Early-Stage Non-Small Cell Lung Cancer Stereotactic Body Radiation Therapy (SBRT) Outcomes in an Equal Access Military Setting

Introduction Lung stereotactic body radiation therapy (SBRT) is a first-line treatment for early-stage lung cancer in non-surgical candidates or those who refuse surgery. We compared our institutional outcomes from a unique patient population with decreased barriers to care with a recently published prospective series. Materials and methods  We retrospectively reviewed all patients who received definitive lung SBRT at the Walter Reed National Military Medical Center from 2015 to 2020. All patients underwent a positron emission tomography-computed tomography (PET-CT) and all were presented at a multidisciplinary tumor board. Patients were treated on a Trubeam linear accelerator (LINAC)-based system with daily cone-beam CT. The results were qualitatively compared to outcomes from prospective studies including RTOG 0236 and RTOG 0618. Results A total of 105 patients with 114 lesions were included. Median age was 77 years and 54.7% had ≥ 40-pack year smoking history. 36.8% did not have pathologic confirmation. With a median follow-up of 24 months, three-year local control (LC), disease-free survival (DFS) and overall survival (OS) rates were 92.4%, 81.0%, and 80.0%, respectively. Rates of Grade 1 and 2 toxicity were 21.9% and 6.7% and no patients experienced Grade ≥ 3 toxicity. Conclusions In our military setting with universal coverage and routine multidisciplinary care, lung SBRT provides outcomes comparable to prospective studies conducted at high-volume academic centers. More than one-third of patients were treated empirically without pathologic confirmation of disease, demonstrating a difference between clinical trials and community practice. Further investigation is warranted to integrate multidisciplinary management and achieve equal access to care to bridge existing health disparities in the community setting.

Dose-Volume Predictors of Radiation Pneumonitis After Lung Stereotactic Body Radiation Therapy (SBRT): Implications for Practice and Trial Design

Background and purpose

Recently published HyTEC report summarized lung toxicity data and proposed guidelines of mean lung dose (MLD) <8 Gy and normal lung receiving at least 20 Gy, V_20Gy<10-15% to avoid lung toxicity. Support for preferred use of a particular dosimetric parameter has been limited. We performed a detailed dose-volume analysis of data on radiation pneumonitis (RP) following lung stereotactic body radiation therapy (SBRT) to search for parameters showing the strongest correlation with RP.

Materials and methods

Two patient cohorts (primary and metastatic lung tumor patients) from previously reported studies were analyzed. Total number of patients was 96, and incidence of grade ≥2 RP was 13.5% (13/96). Fitting to the logistic function was performed to investigate correlation between incidence of RP and reported dosimetric and volumetric parameters. Another independent cohort was used to explore correlation between dosimetric parameters.

Results

Among normal lung parameters (MLD and reported V_x), only MLD consistently showed significant correlation with incidence of RP. Gross tumor volume (GTV), internal target volume, planning target volume (PTV), and minimum dose covering 95% of GTV or PTV did not show statistical significance. A significant correlation between reported V_x and MLD was observed in all cohorts.

Conclusions

In considering tumor- and target-specific (e.g., GTV, PTV) and normal lung-specific (e.g., MLD, V_x) metrics, MLD was the only parameter that consistently correlated with incidence of RP across both cohorts. Because SBRT planning constraints allow small normal lung volumes to receive high doses, utility of MLD is not obvious. The parallel structure of lung is one possible explanation, but correlation between dosimetric parameters obscures elucidation of the preferred or mechanistically based parameter to guide radiotherapy planning.

A comparison of two modalities of stereotactic body radiation therapy for peripheral early-stage non-small cell lung cancer: results of a prospective French study

OBJECTIVES

This prospective, observational, non-randomized multicentric study was conducted to compare efficiency and toxicity using different modalities of stereotactic body radiation therapy (SBRT) in early-stage peripheral non-small cell lung cancer (NSCLC).

METHODS

From 9 April to 11 December, 106 patients were treated according to the local equipment availability for peripheral NSCLC with SBRT: 68 by linear accelerator equipped for SBRT and 38 by Cyberknife^®. Multivariate analysis and propensity score analysis using Inverse Probability Treatment Weighting (IPTW) were undertaken in an effort to adjust for potential bias due to non-randomization.

RESULTS

2-year local control rates were 97.0% (95% CI: [90.6%; 99.4%]) with SBRT by Linac vs 100% (95% CI: ([100%; 100%]) with Cyberknife^® (p = 0.2839). 2-year PFS and 2-year OS rates were 52.7% (95% CI [39.9%;64.0%]) versus 54.1% (95% CI [36.8; 68.6%]) (p = 0.8582) and 65.1% (95% CI: [51.9%; 75.5%] versus 83.9% (95% CI: [67.5%; 92.4%] (p = 0.0831) using Linac and Cyberknife^® respectively. Multivariate regression analysis indicates no significant effect of SBRT treatment type on PFS or OS. Local relapse could not be modeled due to the small number of events (n = 2). Acute and late toxicity rates were not significantly different. After IPTW adjustment, results were unchanged.

CONCLUSIONS

No difference in efficiency or toxicity was shown after SBRT of peripheral NSCLC treatment using Linac or Cyberknife^®.

ADVANCES IN KNOWLEDGE

This is the first large prospective non-randomized study focusing on peripheral localized NSCLC comparing SBRT using an appropriately equipped linac with Cyberknife^®. No significant difference in efficiency or toxicity was shown in this situation.

Which patients benefit most from stereotactic body radiotherapy or surgery in medically operable non-small cell lung cancer? An in-depth look at patient characteristics on both sides of the debate

The role of stereotactic body radiotherapy (SBRT) in early stage medically operable non-small cell lung cancer is currently under debate. SBRT's advantage is its ability to provide high radiotherapy doses to a tumor in a short timeframe, without the risk of postoperative complications and mortality. Currently, in part due to limited prospective data comparing both treatments, international guidelines continue to recommend surgical resection as the gold standard for medically operable patients. However, not all patients possess uniform characteristics, and there is some evidence that certain subgroups of patients would benefit more from one form of treatment - SBRT or surgery - than the other. The aim of this review is to provide a brief summary of the evidence comparing SBRT to surgery, followed by a deeper discussion of the subgroups of patients who would benefit most from surgery: those with large tumors, centrally located tumors, increased risk of occult nodal metastases, increased risk of toxicity from radiotherapy and radioresistant histological tumor subtypes. Meanwhile, patients who could benefit most from SBRT might include elderly patients, those with reduced lung function or cardiac comorbidities, those with synchronous lung nodules, and those with specific tumor mutational status. We hope that this review will aid in the clinical decision-making process regarding patient selection for either treatment.

Stereotactic body radiation therapy with higher biologically effective dose is associated with improved survival in stage II non-small cell lung cancer

OBJECTIVES

The role of stereotactic body radiation therapy (SBRT) in treating stage II non-small cell lung cancer (NSCLC) remains unclear. This study evaluates SBRT dose prescription patterns and survival outcomes in Stage II NSCLC using the National Cancer Database (NCDB).

MATERIALS AND METHODS

Patients diagnosed with Stage II NSCLC and treated with SBRT between 2004-2013 were identified in NCDB. The biologically effective dose with α/β = 10 Gy (BED₁₀) was calculated. Overall survival (OS) was analyzed using the Kaplan-Meier method and Cox regression models.

RESULTS

Of 56,543 patients with Stage II NSCLC, 451 (0.8%) received SBRT. There were 360 patients (79.8%) with node-negative and 91 patients (20.2%) with node-positive disease. The most common prescriptions were 10 Gy x 5 (35.9%) and 12 Gy x 4 (19.3%). The mean and median BED₁₀ were 114.9 Gy and 105.6 Gy, respectively. With median follow-up of 19.3 months, overall median survival was 23.7 months. Median survival was 22.4 months for those treated with BED₁₀ < 114.9 Gy versus 31.5 months for BED₁₀ ≥ 114.9 Gy (p = 0.036). On multivariate analysis, BED₁₀ as a continuous variable (hazard ratio [HR] 0.991, p = 0.009) and ≥ 114.9 Gy (HR 0.63, p = 0.015) were associated with improved survival in node-negative patients. BED₁₀ as a continuous variable (HR 0.997, p = 0.465) and ≥ 114.9 Gy (HR 0.81, p = 0.546) were not significant factors for predicting survival in node-positive patients.

CONCLUSION

SBRT is infrequently utilized to treat Stage II NSCLC in the United States. Treatment with higher BED₁₀ was associated with improved survival, and the benefit was limited to patients with node-negative disease.

Outcomes of pulmonary resection in non-small cell lung cancer patients older than 70 years old

BACKGROUND

An appropriate treatment of older lung cancer patients has become an important issue. The aim of this study is to evaluate the short and long-term surgical outcomes in lung cancer patients using 70 years as a cut-point, and to identify prognostic factors of cancer-specific mortality in patients older than 70 years.

METHODS

Medical records of non-small cell lung cancer (NSCLC) patients who underwent pulmonary resection at Chiang Mai University Hospital from January 2002 through December 2016 were retrospectively reviewed. Patients were divided into age less than 70 years (control group) and 70 years or more (study group). Primary outcomes were major post-operative complications and in-hospital death (POM); secondary outcome was long-term survival. Multivariable regression analysis was used.

RESULTS

This study included 583 patients, 167 for study group, and 416 for control group. There were no differences in POM, both at univariable and multivariable analyses, however, for long-term cancer-specific mortality, the study group was more likely to die (HR_adj = 1.40, 95%CI = 1.03-1.89). Adverse prognostic factors for long-term mortality in study group were having universal coverage scheme (HR_adj = 1.70, 95%CI = 1.03-2.79), the presence of intratumoral lymphatic invasion (HR_adj = 2.83, 95%CI = 1.28-6.29), perineural invasion (HR_adj = 2.80, 95%CI = 1.13-6.94), underwent lymph node sampling (HR_adj = 2.23, 95%CI = 1.16-4.30) and higher stage of disease (HR_adj = 2.02, 95%CI = 1.06-3.85 for stage III, HR_adj = 3.40, 95%CI = 1.29-8.94 for stage IV).

CONCLUSIONS

In-hospital mortality and composite post-operative complications are acceptable in pulmonary resection for NSCLC patients older than 70 years. However, these patients had shorter long-term survival, especially who have some adverse prognostic factors. Further studies with larger sample size are warranted.

Pattern of recurrence after CyberKnife stereotactic body radiotherapy for peripheral early non-small cell lung cancer

Background

The treatment efficacy after CyberKnife stereotactic body radiotherapy (SBRT) have not been adequately addressed. The purpose of this study was to investigate pattern of recurrence according to irradiation field after CyberKnife SBRT for early-stage non-small cell lung cancer (NSCLC).

Methods

This retrospective study included patients with peripheral cT1/2N0M0 NSCLC that was treated with SBRT using a CyberKnife between May 2013 and March 2016 at single institute and followed up by more than two imaging examinations. Both operable and inoperable patients were included. Overall survival (OS) and progression-free survival (PFS) curves were estimated using the Kaplan-Meier method with 95% confidence intervals (CI). Cumulative incidence curves of recurrence were calculated and compared using the Gray's test.

Results

Total 71 patients were included and analyzed in this study. The median follow-up period for surviving patients was 34 months (range, 7-64 months). The 2-year OS and PFS rate were 93% (95% CI: 83-97%) and 77% (95% CI: 65-86%), respectively. The 2-year cumulative incidence rate of infield recurrence and out-of-field recurrence were 6% (95% CI: 2-14%) and 17% (95% CI: 9-27%), respectively. Gross tumor volume (GTV) ≥9 mL and diagnosis-to-treatment interval (DTI) ≥90 days were significantly associated with infield recurrence (P<0.001 and P=0.007), and epidermal growth factor receptor (EGFR) mutation was significantly associated with out-of-field recurrence (P=0.014).

Conclusions

Treatment efficacy after CyberKnife SBRT for peripheral early-stage NSCLC was identical to previous conventional linac-based SBRT reports. With short follow-up period, it was found that GTV and DTI were the significant predictive factor of infield recurrence, and EGFR mutation was the significant predictive factor of out-of-field recurrence.

Salvage Stereotactic Body Radiation Therapy for Locally Recurrent Previously Irradiated Head and Neck Squamous Cell Carcinoma: An Analysis from the RSSearch® Registry

Objectives

To report on overall survival (OS), local control (LC), dose-outcome relationships, and related toxicities following stereotactic body radiation therapy (SBRT) for locally recurrent, previously irradiated squamous cell carcinoma of the head and neck (rSCCHN).

Methods

We queried the prospectively-maintained RSSearch® Registry for patients with rSCCHN treated with five-fraction SBRT from January 2008 to November 2016. Patients with non-squamous cell histology, missing registry data regarding prior irradiation, those treated with less than five fractions of SBRT, and those treated with SBRT in primary or boost settings were excluded. LC and OS were estimated using the Kaplan-Meier method with comparisons between groups completed using log-rank t-tests and multivariable Cox regression. Logistic regression analyses were used to examine factors predictive of toxicity.

Results

Forty-five rSCCHN patients treated with SBRT delivered in five fractions at 12 radiotherapy centers were identified. Prescription doses ≥ 40 Gy were associated with higher one-year rates of OS, LC, and a higher likelihood of experiencing toxicities. Acute and late toxicity rates were low (22.2% and 15.6%, respectively) and were all Grade 1-2 with only one late Grade 3 esophagitis.

Conclusion

Salvage SBRT for rSCCHN resulted in outcomes comparable to prior single-institutional reports in a multi-institutional cohort across clinical settings with low toxicity, thus supporting more widespread adoption of SBRT with recommended doses ≥ 40 Gy.

Clinical Results of Mean GTV Dose Optimized Robotic-Guided Stereotactic Body Radiation Therapy for Lung Tumors

Introduction

We retrospectively evaluated the efficacy and toxicity of gross tumor volume (GTV) mean dose optimized stereotactic body radiation therapy (SBRT) for primary and secondary lung tumors with and without robotic real-time motion compensation.

Materials and methods

Between 2011 and 2017, 208 patients were treated with SBRT for 111 primary lung tumors and 163 lung metastases with a median GTV of 8.2 cc (0.3–174.0 cc). Monte Carlo dose optimization was performed prioritizing GTV mean dose at the potential cost of planning target volume (PTV) coverage reduction while adhering to safe normal tissue constraints. The median GTV mean biological effective dose (BED)₁₀ was 162.0 Gy₁₀ (34.2–253.6 Gy₁₀) and the prescribed PTV BED₁₀ ranged 23.6–151.2 Gy₁₀ (median, 100.8 Gy₁₀). Motion compensation was realized through direct tracking (44.9%), fiducial tracking (4.4%), and internal target volume (ITV) concepts with small (≤5 mm, 33.2%) or large (>5 mm, 17.5%) motion. The local control (LC), progression-free survival (PFS), overall survival (OS), and toxicity were analyzed.

Results

Median follow-up was 14.5 months (1–72 months). The 2-year actuarial LC, PFS, and OS rates were 93.1, 43.2, and 62.4%, and the median PFS and OS were 18.0 and 39.8 months, respectively. In univariate analysis, prior local irradiation (hazard ratio (HR) 0.18, confidence interval (CI) 0.05–0.63, p = 0.01), GTV/PTV (HR 1.01–1.02, CI 1.01–1.04, p < 0.02), and PTV prescription, mean GTV, and maximum plan BED₁₀ (HR 0.97–0.99, CI 0.96–0.99, p < 0.01) were predictive for LC while the tracking method was not (p = 0.97). For PFS and OS, multivariate analysis showed Karnofsky Index (p < 0.01) and tumor stage (p ≤ 0.02) to be significant factors for outcome prediction. Late radiation pneumonitis or chronic rip fractures grade 1–2 were observed in 5.3% of the patients. Grade ≥3 side effects did not occur.

Conclusion

Robotic SBRT is a safe and effective treatment for lung tumors. Reducing the PTV prescription and keeping high GTV mean doses allowed the reduction of toxicity while maintaining high local tumor control. The use of real-time motion compensation is strongly advised, however, well-performed ITV motion compensation may be used alternatively when direct tracking is not feasible.

Microwave ablation for lung cancer patients with a single lung: Clinical evaluation of 11 cases

Background

The study was conducted to retrospectively evaluate the safety and effectiveness of computed tomography (CT)‐guided percutaneous microwave ablation (MWA) for peripheral non‐small cell lung cancer (NSCLC) in 11 patients with a single lung after pneumonectomy.

Methods

From May 2011 to March 2015, 11 single‐lung patients (8 men and 3 women; mean age 60.3 years, range 46–71) with peripheral NSCLC underwent 12 sessions of MWA. Eleven tumors measuring 13–52 mm (mean 30.2 mm) were treated. Follow‐up was performed via CT scan at 1, 3, 6, 12, 18, and 24 months after the procedure and annually thereafter. Clinical outcomes were evaluated and complications after MWA were summarized.

Results

At a median follow‐up period of 20 months (range 6–38), four patients showed evidence of local recurrence at a rate of 36.4% (4/11). Median overall survival was 20 months. The overall survival rates at one, two, and three years after MWA were 88.7%, 63.6%, and 42.3%, respectively. Complications after MWA included pneumothorax (33.3%), hemoptysis (33.3%), intrapulmonary bleeding (25%), pleural effusion (16.7%), and pulmonary infection (8.3%). None of the patients died during the procedure or in the 30 days after MWA.

Conclusion

CT‐guided percutaneous MWA is safe and effective for the treatment of peripheral NSCLC in patients with a single lung after prior pneumonectomy.

Stereotactic Body Radiotherapy (SBRT) for liver metastasis - clinical outcomes from the international multi-institutional RSSearch® Patient Registry

Background

Stereotactic body radiotherapy (SBRT) is an emerging treatment option for liver metastases in patients unsuitable for surgery. We investigated factors associated with clinical outcomes for liver metastases treated with SBRT from a multi-center, international patient registry.

Methods

Patients with liver metastases treated with SBRT were identified in the RSSearch® Patient Registry. Patient, tumor and treatment characteristics associated with treatment outcomes were assessed. Dose fractionations were normalized to BED₁₀. Overall survival (OS) and local control (LC) were evaluated using Kaplan Meier analysis and log-rank test.

Results

The study included 427 patients with 568 liver metastases from 25 academic and community-based centers. Median age was 67 years (31–91 years). Colorectal adenocarcinoma (CRC) was the most common primary cancer. 73% of patients received prior chemotherapy. Median tumor volume was 40 cm³ (1.6–877 cm³), median SBRT dose was 45 Gy (12–60 Gy) delivered in a median of 3 fractions [1–5]. At a median follow-up of 14 months (1–91 months) the median overall survival (OS) was 22 months. Median OS was greater for patients with CRC (27 mo), breast (21 mo) and gynecological (25 mo) metastases compared to lung (10 mo), other gastro-intestinal (GI) (18 mo) and pancreatic (6 mo) primaries (p < 0.0001). Smaller tumor volumes (< 40 cm³) correlated with improved OS (25 months vs 15 months p = 0.0014). BED₁₀ ≥ 100 Gy was also associated with improved OS (27 months vs 15 months p < 0.0001). Local control (LC) was evaluable in 430 liver metastases from 324 patients. Two-year LC rates was better for BED₁₀ ≥ 100 Gy (77.2% vs 59.6%) and the median LC was better for tumors < 40 cm³ (52 vs 39 months). There was no difference in LC based on histology of the primary tumor.

Conclusions

In a large, multi-institutional series of patients with liver metastasis treated with SBRT, reasonable LC and OS was observed. OS and LC depended on dose and tumor volume, while OS varied by primary tumor. Future prospective trials on the role of SBRT for liver metastasis from different primaries in the setting of multidisciplinary management including systemic therapy, is warranted.

Trial registration

Clinicaltrials.gov: NCT01885299.

Stereotactic body radiotherapy for centrally located stage I non-small cell lung cancer

Stereotactic body radiotherapy (SBRT) has become the standard of care for the treatment of early stage non-small cell lung cancer in high risk or medically inoperable patients. It is very well tolerated when given to peripherally located tumors and is associated with high rates of local control. Centrally located tumors represent a bigger challenge as they are closer to a number of critical structures, namely the major bronchi, esophagus, large vessels and brachial plexus, that can be damaged by the high ablative doses of SBRT needed for optimal tumor control. Thus, the fractionation schedule for centrally located tumors needs to balance the need for tumor control while minimizing the risk of significant radiotherapy toxicity. In this article, we review the current evidence, summarize the prospective and retrospective studies of SBRT for centrally located tumors, and highlight several practical considerations.

Breathing-motion-compensated robotic guided stereotactic body radiation therapy : Patterns of failure analysis

PURPOSE

We retrospectively evaluated the patterns of failure for robotic guided real-time breathing-motion-compensated (BMC) stereotactic body radiation therapy (SBRT) in the treatment of tumors in moving organs.

PATIENTS AND METHODS

Between 2011 and 2016, a total of 198 patients with 280 lung, liver, and abdominal tumors were treated with BMC-SBRT. The median gross tumor volume (GTV) was 12.3 cc (0.1-372.0 cc). Medians of mean GTV BED_{α/β =10 Gy} (BED = biological effective dose) was 148.5 Gy₁₀ (31.5-233.3 Gy₁₀) and prescribed planning target volume (PTV) BED_{α/β =10 Gy} was 89.7 Gy₁₀ (28.8-151.2 Gy₁₀), respectively. We analyzed overall survival (OS) and local control (LC) based on various factors, including BEDs with α/β ratios of 15 Gy (lung metastases), 21 Gy (primary lung tumors), and 27 Gy (liver metastases).

RESULTS

Median follow-up was 10.4 months (2.0-59.0 months). The 2‑year actuarial LC was 100 and 86.4% for primary early and advanced stage lung tumors, respectively, 100% for lung metastases, 82.2% for liver metastases, and 90% for extrapulmonary extrahepatic metastases. The 2‑year OS rate was 47.9% for all patients. In uni- and multivariate analysis, comparatively lower PTV prescription dose (equivalence of 3 × 12-13 Gy) and higher average GTV dose (equivalence of 3 × 18 Gy) to current practice were significantly associated with LC. For OS, Karnofsky performance score (100%), gender (female), and SBRT without simultaneous chemotherapy were significant prognostic factors. Grade 3 side effects were rare (0.5%).

CONCLUSIONS

Robotic guided BMC-SBRT can be considered a safe and effective treatment for solid tumors in moving organs. To reach sufficient local control rates, high average GTV doses are necessary. Further prospective studies are warranted to evaluate these points.

Inversed-Planned Respiratory Phase Gating in Lung Conformal Radiation Therapy

PURPOSE

To assess whether the optimal gating window for each beam during lung radiation therapy with respiratory gating will be dependent on a variety of patient-specific factors, such as tumor size and location and the extent of relative tumor and organ motion.

METHODS AND MATERIALS

To create optimal gating treatment plans, we started from an optimized clinical plan, created a plan per respiratory phase using the same beam arrangements, and used an inverse planning optimization approach to determine the optimal gating window for each beam and optimal beam weights (ie, monitor units). Two pieces of information were used for optimization: (1) the state of the anatomy at each phase, extracted from 4-dimensional computed tomography scans; and (2) the time spent in each state, estimated from a 2-minute monitoring of the patient's breathing motion. We retrospectively studied 15 lung cancer patients clinically treated by hypofractionated conformal radiation therapy, for whom 45 to 60 Gy was administered over 3 to 15 fractions using 7 to 13 beams. Mean gross tumor volume and respiratory-induced tumor motion were 82.5 cm³ and 1.0 cm, respectively.

RESULTS

Although patients spent most of their respiratory cycle in end-exhalation (EE), our optimal gating plans used EE for only 34% of the beams. Using optimal gating, maximum and mean doses to the esophagus, heart, and spinal cord were reduced by an average of 15% to 26%, and the beam-on times were reduced by an average of 23% compared with equivalent single-phase EE gated plans (P<.034, paired 2-tailed t test).

CONCLUSIONS

We introduce a personalized respiratory-gating technique in which inverse planning optimization is used to determine patient- and beam-specific gating phases toward enhancing dosimetric quality of radiation therapy treatment plans.

Clinical Outcomes of 130 Patients with Primary and Secondary Lung Tumors treated with Cyberknife Robotic Stereotactic Body Radiotherapy

Background

Authors report clinical outcomes of patients treated with robotic stereotactic body radiotherapy (SBRT) for primary, recurrent and metastatic lung lesions.

Patients and methods

130 patients with 160 lesions were treated with Cyberknife SBRT, including T1-3 primary lung cancers (54%), recurrent tumors (22%) and pulmonary metastases (24%). The mean biologically equivalent dose (BED_10Gy) was 151 Gy (72–180 Gy). Median prescribed dose for peripheral and central lesions was 3×20 Gy and 3×15 Gy, respectively. Local control (LC), overall survival (OS), and cause-specific survival (CSS) rates, early and late toxicities are reported. Statistical analysis was performed to identify factors influencing local tumor control.

Results

Median follow-up time was 21 months. In univariate analysis, higher dose was associated with better LC and a cut-off value was detected at BED_10Gy ≤ 112.5 Gy, resulting in 1-, 2-, and 3-year actuarial LC rates of 93%, vs 73%, 80% vs 61%, and 63% vs 54%, for the high and low dose groups, respectively (p = 0.0061, HR = 0.384). In multivariate analysis, metastatic origin, histological confirmation and larger Planning Target Volume (PTV) were associated with higher risk of local failure. Actuarial OS and CSS rates at 1, 2, and 3 years were 85%, 74% and 62%, and 93%, 89% and 80%, respectively. Acute and late toxicities ≥ Gr 3 were observed in 3 (2%) and 6 patients (5%), respectively.

Conclusions

Our favorable LC and survival rates after robotic SBRT, with low rates of severe toxicities, are coherent with the literature data in this mixed, non-selected study population.

Guideline for radiotherapy with curative intent in patients with early-stage medically inoperable non-small-cell lung cancer

OBJECTIVES

For this guideline, we investigated the effectiveness of radiotherapy with curative intent in medically inoperable patients with early-stage non-small-cell lung cancer (nsclc).

METHODS

The guideline was developed by Cancer Care Ontario's Program in Evidence-Based Care and by the Lung Cancer Disease Site Group through a systematic review of mainly retrospective studies, expert consensus, and formal internal and external reviews.

RECOMMENDATIONS

■ Stereotactic body radiation therapy (sbrt) with curative intent is an option that should be considered for patients with early-stage, node-negative, medically inoperable nsclc. Qualifying Statements■ Because of the high dose per fraction, the planning process and treatment delivery for sbrt require the use of advanced technology to maintain an appropriate level of safety. Consistent patient positioning and 4-dimensional analysis of tumour and critical structure motion during simulation and treatment delivery are essential.■ Preliminary results for proton-beam therapy have been promising, but the technique requires further clinical study.■ Recommended fractionation schemes for sbrt should result in a biologically effective dose of 100 or greater by the linear quadric model, choosing an α/β value of 10 [bed_10(LQ) ≥ 100]. Qualifying Statements■ Because of the increased risk of treatment-related adverse events associated with centrally located tumours, consideration of tumour size and proximity to critical central structures is required when determining the dose and fractionation.■ Examples of dose-fractionation schemes used in the included studies have been provided.■ Based on the current evidence and the opinion of the authors, radiation doses at bed_10(LQ) greater than 146 might significantly increase toxicity and should be avoided.■ Determination of the radiation bed by the linear quadratic model has limitations for the extreme hypofractionated schemes used in sbrt.

A Dose Escalation Clinical Trial of Single-Fraction Carbon Ion Radiotherapy for Peripheral Stage I Non-Small Cell Lung Cancer

OBJECTIVES

Our objective was to report initial results of a dose escalation trial of single-fraction carbon ion radiotherapy for peripheral stage I NSCLC.

METHODS

Between April 2003 and February 2012, a total of 218 patients were treated. The total dose was raised from 28 to 50 Gy (relative biological effectiveness [RBE]). There were 157 male and 61 female patients, with a median age of 75 years. Of the tumors, 123 were stage T1 and 95 were stage T2. A total of 134 patients (61.5%) were medically inoperable. By histological type, there were 146 adenocarcinomas, 68 squamous cell carcinomas, three large cell carcinomas, and one mucoepidermoid carcinoma.

RESULTS

The median follow-up was 57.8 months (range 1.6-160.7). The overall survival rate at 5 years was 49.4%. The local control (LC) rate was 72.7%. A statistically significant difference in LC rate (p = 0.0001, log-rank test) was seen between patients receiving 36 Gy (RBE) or more and those receiving less than 36 Gy (RBE). In 20 patients irradiated with 48 to 50 Gy (RBE), the LC rate at 5 years was 95.0%, the overall survival rate was 69.2%, and the progression-free survival rate was 60.0% (median follow-up was 58.6 months). With dose escalation, LC tended to improve. As for adverse lung and skin reactions, there were no patients with grade 3 or higher reactions, and less than 2% had a grade 2 reaction. Regarding chest wall pain, only one patient had grade 3 late toxicity.

CONCLUSIONS

We have reported the outcome of a dose escalation study of single-fraction carbon ion radiotherapy for stage I NSCLC, showing the feasibility of obtaining excellent results comparable to those with previous fractionated regimens.

Clinical outcomes of video-assisted thoracic surgery and stereotactic body radiation therapy for early-stage non-small cell lung cancer: A meta-analysis

Background

We compared video‐assisted thoracoscopic surgery (VATS) lobectomy and stereotactic body radiation therapy (SABR) to explore clinical outcomes in the treatment of patients with early stage NSCLC.

Methods

Major medical databases were systematically searched to identify studies on VATS and SBRT published between January 2010 and October 2015. English publications of stage I and II NSCLC with adequate patients and SBRT doses were included. A multivariate random effects model was used to perform meta‐analysis to compare overall survival (OS) and disease‐free survival (DFS) between VATS and SBRT, adjusting for median age and operable patient numbers.

Results

Thirteen VATS (3436 patients) and 24 SBRT (4433) studies were eligible. The median age and follow‐up duration was 68 years and 42 months for VATS and 74 years and 29.4 months for SBRT patients. After adjusting for the proportion of operable patients and median age, the estimated OS rates at one, two, three, and five years with VATS were 94%, 89%, 84%, and 69% compared with 96%, 94%, 89%, and 82% for SBRT. The estimated DFS rates at one, two, three, and five years with VATS were 97%, 93%, 87%, and 77% compared with 86%, 80%, 73%, and 58% for SBRT.

Conclusion

Before adjustment, patients treated with SBRT had poorer clinical outcomes compared to those treated with VATS. A substantial difference between median age and operability exists between patients treated with SBRT and VATS. After adjusting for these differences, OS and DFS did not differ significantly between the two techniques.

[Comparison of Clinical Outcomes of VATS and SBRT in the Treatment of NSCLC]

BACKGROUND AND OBJECTIVE

More and more chest physicians chose video-assisted thoracoscopic surgery (VATS) to treat early stage non-small cell lung cancer (NSCLC). In recent years, there is still lack of a random trial comparing the clinical outcomes of VATS and stereotactic body radiotherapy (SBRT) in treating NSCLC. To provide a reference for the choice between VATS and SBRT, in the current meta-analysis, we compared the clinical outcomes of these two therapies in treating NSCLC.

METHODS

Five major medical databases, CNKI, CPVIP (http://www.cqvip.com/), PubMed, Embase, and ISI web of science were systematically searched to identify all studies from January 2010 to February 2016 on VATS and SBRT therapies. Finally, original English or Chinese publications of stage I and II NSCLC with adequate patients and adequate SBRT doses were enrolled. A multivariate random effects model was used to perform a meta-analysis to compare overall survival and disease free survival between VATS and SBRT while adjusting for median age and operable patient numbers.

RESULTS

Fourteen VATS studies (included 3,482 patients) and nineteen SBRT studies (included 3,997 patients) published in the same period were eligible. The median age and follow-up duration were 64 years and 43.4 months for VATS patients and 74 years and 29.5 months for SBRT patients, respectively. The mean unadjusted overall survival rates at 1, 2, 3, and 5 years with VATS were 93.5%, 84.9%, 77.0% and 76.3% compared to 89.0% 73.3% 59.0% and 36.7% with SBRT. The mean unadjusted disease free survival rates at 1, 2, 3, and 5 years with VATS were 93.6%, 88.6%, 85.6% and 75.6% compared to 79.3%, 72.1%, 64.9% and 58.9% with SBRT. While, after adjusted for proportion of operable patients and median age, the estimate overall survival rates at 1, 2, 3, and 5 years with VATS were 94%, 92%, 84% and 71% compared to 98%, 95%, 87% and 83% with SBRT. And the estimate disease free survival rates at 1, 2, 3, and 5 years with VATS were 97%, 94%, 85% and 75% compared to 88%, 81%, 74% and 63% with SBRT.

CONCLUSION

Before adjustment, the SBRT group showed worse clinical outcomes (overall survival and disease free survival) than VATS group. When take consider of median age and operability, the patients with SBRT differ substantially from patients treated with VATS. After adjustment of median age and operability, there are no significant differences between these two therapy in treating NSCLC.