Stereotactic hypofractionated radiotherapy for stage I non-small cell lung cancer—Mature results for medically inoperable patients

Oligometastatic Head and Neck Cancer: Challenges and Perspectives

Simple Summary

Oligometastasis represents a disease state and an opportunity for cure when metastases emerge. Emerging evidence supports that most head and neck cancer patients with oligometastatic disease are likely to benefit from curative intent local ablative therapy if appropriate selection criteria are applied. Biomarkers to predict development of oligometastasis, as well as to identify which patients could benefit from a radical intent approach, are under investigation. This review summarizes recent knowledge about the characteristics, investigational efforts, and evidence for local ablation regarding oligometastasis in head and neck cancer. We also describe the challenges and opportunities in patient selection and discuss the role of radiotherapy and immunotherapy combinations to enhance anti-tumor immunity.

Abstract

A minority of patients with metastatic head and neck squamous cell carcinoma (HNSCC) present with oligometastatic disease. Oligometastasis not only reflects a disease state, but might also present an opportunity for cure in the metastatic setting. Radical ablation of all oligometastatic sites may confer prolonged survival and possibly achieve cure in some patients. However, substantial debate remains about whether patients with oligometastatic disease could benefit from curative intent therapy or whether aggressive treatments expose some patients to futile toxicity. Optimal selection of patients, carefully balancing the currently known prognostic factors against the risks of toxicity is critical. Emerging evidence suggests that patients with a limited burden of disease, viral-related pharyngeal cancer, metachronous metastasis and lung-only metastasis may benefit most from this approach. Efforts are underway to identify biomarkers that can detect oligometastasis and better select patients who would derive the maximum benefit from an aggressive radical approach. The combination of radiotherapy and immunotherapy promises to enhance the anti-tumoral immune response and help overcome resistance. However, optimization of management algorithms, including patient selection, radiation dose and sequencing, will be critical in upcoming clinical trials. This review summarizes recent knowledge about the characteristics and investigational efforts regarding oligometastasis in HNSCC.

GOECP/SEOR radiotheraphy guidelines for non-small-cell lung cancer

Non-small cell lung cancer (NSCLC) is a heterogeneous disease accounting for approximately 85% of all lung cancers. Only 17% of patients are diagnosed at an early stage. Treatment is multidisciplinary and radiotherapy plays a key role in all stages of the disease. More than 50% of patients with NSCLC are treated with radiotherapy (curative-intent or palliative). Technological advances-including highly conformal radiotherapy techniques, new immobilization and respiratory control systems, and precision image verification systems-allow clinicians to individualize treatment to maximize tumor control while minimizing treatment-related toxicity. Novel therapeutic regimens such as moderate hypofractionation and advanced techniques such as stereotactic body radiotherapy (SBRT) have reduced the number of radiotherapy sessions. The integration of SBRT into routine clinical practice has radically altered treatment of early-stage disease. SBRT also plays an increasingly important role in oligometastatic disease. The aim of the present guidelines is to review the role of radiotherapy in the treatment of localized, locally-advanced, and metastatic NSCLC. We review the main radiotherapy techniques and clarify the role of radiotherapy in routine clinical practice. These guidelines are based on the best available evidence. The level and grade of evidence supporting each recommendation is provided.

Patterns of Use of Stereotactic Body Radiation Therapy Compared With Surgery for Definitive Treatment of Primary Early-stage Non-small Cell Lung Cancer

OBJECTIVE

As stereotactic body radiation therapy (SBRT) becomes widely available for early-stage non-small cell lung cancer (NSCLC), there may be concerns in the surgical community that SBRT is being offered for patients with operable tumors, even though surgery is standard of care. We evaluated the trends in SBRT and surgery over time for patients with NSCLC.

MATERIALS AND METHODS

The National Cancer Database was queried for patients with node-negative NSCLC ≤5 cm from 2004 to 2016. The relationships between definitive local treatment modalities and year were analyzed using a multinomial regression model while controlling for other covariates.

RESULTS

Among the 202,367 patients who met the inclusion criteria, there was a steady decrease in mean tumor size in all treatment modalities, from 2.44 cm (SD=1.08) to 2.25 cm (SD=1.00) over the study period. In the multinomial model, the probability of receiving lobectomy demonstrated a slight decline from 58% (2004) to 53% (2016). The use of SBRT increased from 1% to 20%, while patients receiving no therapy declined from 27% to 16%. The likelihood of SBRT increased with year of diagnosis (P<0.0001) and decreasing tumor size (P<0.0001), compared with lobectomy. Age, race, income, facility, and Charlson-Deyo score were also associated with treatment modality.

CONCLUSIONS

The mean tumor size of early-stage NSCLC decreased over the study period for all treatment modalities. SBRT use has increased, mostly among older patients with smaller tumors and Charlson-Deyo scores ≥3. The increase in SBRT contributed to the significant decline in patients who had no therapy.

Comparison of stereotactic body radiotherapy and radiofrequency ablation for early-stage non-small cell lung cancer: a systematic review and meta-analysis

Background

Stereotactic body radiation therapy (SBRT) and radiofrequency ablation (RFA) are recommended for patients with inoperable early-stage non-small cell lung cancer (NSCLC), with both offering promising results. However, it is largely unknown which of these two treatment modalities provides superior benefits for patients. Therefore, this systematic review and meta-analysis compared clinical outcomes and safety between SBRT and RFA in patients with inoperable early-stage NSCLC.

Methods

Eligible studies published between 2001 and 2020 were obtained through a comprehensive search of the PubMed, Medline, Embase, and Cochrane Library databases. Original English-language studies on the treatment of early-stage NSCLC with SBRT or RFA were included. Local control (LC) rates, overall survival (OS) rates, and adverse events were obtained by pooled analyses.

Results

Eighty-seven SBRT studies (12,811 patients) and 18 RFA studies (1,535 patients) met the eligibility criteria. For SBRT, the LC rates (with 95% confidence intervals) at 1, 2, 3, and 5 years were 98% (97-98%), 95% (95-96%), 92% (91-93%), and 92% (91-93%), respectively, which were significantly higher than those for RFA [75% (69-82%), 31% (22-39%), 67% (58-76%), and 41% (30-52%), respectively] (P<0.01). There were no significant differences in short-term OS between SBRT and RFA [1-year OS rate: 87% (86-88%) versus 89% (88-91%), P=0.07; 2-year OS rate: 71% (69-72%) versus 69% (64-74%), P=0.42]. Regarding long-term OS, the 3- and 5-year OS rates for SBRT were 58% (56-59%) and 39% (37-40%), respectively, which were significantly (P<0.01) superior to those for RFA [48% (45-51%) and 21% (19-23%), respectively]. The most common complication of SBRT was radiation pneumonitis (grade ≥2), making up 9.1% of patients treated with SBRT, while pneumothorax was the most common complication of RFA, making up 27.2% of patients treated with RFA.

Discussion

Compared with RFA, SBRT has superior LC and long-term OS rates but similar short-term OS rates. Prospective randomized trials with large sample sizes comparing the efficacy of SBRT and RFA are warranted.

Chromosomal Aberrations in Blood Lymphocytes as Predictors of Respiratory Function After Stereotactic Lung Irradiation

Due to the profound difference in radiosensitivity of patients and various side effects caused by this phenomenon, a radiosensitivity marker is needed. Prediction by a marker may help personalise the treatment. In this study, we tested chromosomal aberrations (CA) of in vitro irradiated blood as predictor of pulmonary function decrease of nonsmall cell lung cancer (NSCLC) patients and also compared it with the CAs in the blood of irradiated patients. Peripheral blood samples were taken from 45 lung cancer patients before stereotactic radiotherapy (SBRT) and immediately after the last fraction and 3, 6, 9, 12, 15, 18, 21, and 24 months later. Respiratory function measurements were performed at the same time. Diffusing capacity of lung for carbon monoxide (DLCO), forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1s), and FEV1s/FVC (FEV1%) were monitored. Metaphase preparations of lymphocytes were made with standard procedures, and chromosome aberrations were analysed. In our cohort, the 36-month local relapse-free survival was 97.4%, and the distant metastasis-free survival was 71.5% at 36 months. There was no change in the mean of the pulmonary function tests (PFTs) after the therapy. However, there was a considerable variability between the patients. Therefore, we subtracted the baseline and normalised the PFT values. There were significant decreases at 12–24 months in relative FEV1s and relative FEV1%. The tendentious decrease of the PFTs could be predicted by the in vitro chromosome aberration data. We also found connections between the in vitro and in vivo CA values (i.e., dicentrics plus rings after 3 Gy irradiation predicts dicentric-plus-ring value directly after the radiotherapy/V_54 Gy (p = 0.001 24.2%)).

We found that—after further validation—chromosome aberrations resulted from in vitro irradiation before radiotherapy can be a predictive marker of pulmonary function decrease after lung irradiation.

Computed Tomography-Guided Percutaneous Radiofrequency Ablation in Older Adults With Early-Stage Peripheral Lung Cancer: A Retrospective Cohort Study

Objectives

To evaluate the feasibility, safety, and efficacy of computed tomography(CT)-guided percutaneous radiofrequency ablation (RFA) in medically inoperable older adults with clinical stage I non-small cell lung cancer (NSCLC).

Patients and Methods

We retrospectively reviewed the records of medically inoperable older adults (≥70 years) with clinical stage I NSCLC who underwent percutaneous multi-tined electrode RFA at our institution between January 2014 and December 2018. We analyzed the patients’ characteristics, therapy response, survival, as well as the procedure-related complications.

Results

Eighteen patients (10 men and 8 women) with a mean age of 75.9 (71−85) years were treated in during the study period. The median tumor size was 25 mm (range, 19−43 mm); 10 and 8 cases involved stage T1 and T2a disease, respectively. The median follow-up duration was 25 (11–45) months. RFA was technically successful for all 18 lesions, with no treatment-related mortality. The disease control rate was 83.3% (15/18 lesions). There were 6 cases of pneumothorax: one symptomatic case requiring thoracic drainage, and five requiring no treatment. Minor complications, including pulmonary infection, chest pain, fever, and cough, were treated within 4 days (range, 1−4 days). The progression-free survival rates were 83.3%, 64.9%, and 51.9% 1, 2, and 3 years, respectively. The corresponding overall survival rates were 92.2%, 81.5%, and 54.3%, respectively.

Conclusions

CT-guided percutaneous RFA is safe and effective in medically inoperable patients with stage I NSCLC and could be an alternative therapeutic strategy, particularly in older adults with early-stage peripheral lung cancer.

Stereotactic Ablative Radiotherapy for Oligo-Progressive Disease REfractory to Systemic Therapy in Non-Small Cell Lung Cancer: A Registry-based Phase II Randomized Trial (SUPPRESS-NSCLC)

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Treatment of NSCLC patients with oligo-progressive disease on systemic treatment remains controversial.

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This phase II trial evaluates SABR to all oligo-progressive lesions in combination to current systemic therapy.

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PFS and OS between patients treated with SABR with continuation of current systemic therapy vs standard of care will be assessed.

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Intention-to-treat analysis of SABR compared to standard of care will be evaluated.

Background

Management of Non-Small Cell Lung Cancer (NSCLC) patients with oligoprogression remains controversial. There is limited data to support the strategy of Stereotactic Ablative Radiotherapy (SABR) targeting the oligoprogressive disease in combination with ongoing systemic treatment. We aim to assess the benefit of this approach compared to standard of care in the treatment of oligoprogressive NSCLC.

Methods

This phase II study will enroll 68 patients with oligoprogressive NSCLC, defined as 1–5 progressive extracranial lesions ≤5 cm involving ≤3 organs. Patients on active systemic therapy (chemotherapy, immunotherapy, targeted therapy or a combination) will be randomized 1:1 to either continue their current systemic therapy in combination with SABR to all lesions or the standard of care (switch to the next line of treatment, continue same treatment or observation). The co-primary endpoints are progression-free survival (PFS) and overall survival (OS). Secondary endpoints include time to next systemic treatment, patient-reported quality of life, cost effectiveness as well as translational analysis to characterize both adaptive immunity and immunogenic cell death markers in the peripheral blood.

Discussion

There is an unmet need to carefully examine the efficacy, safety and quality of life impact of SABR in the context of oligoprogressive disease. The present study will provide higher level randomized evidence on the role of SABR in oligoprogressive NSCLC.

Stereotactic body radiation therapy for medically inoperable early-stage lung cancer: Tata Memorial Hospital perspective and practice recommendations

Background

Stereotactic body radiotherapy (SBRT) is now considered the standard treatment for medically inoperable early-stage non-small lung cell cancer (ES-NSCLC).

Purpose

There is a paucity of data related to outcomes with SBRT in ES-NSCLC from the developing countries. We report the early outcomes of ES-NSCLC patients treated with SBRT at our institute.

Materials and Methods

Between 2007 and 2015, 40 consecutive patients with histologically proven ES-NSCLC were treated with SBRT. Median age was 71 years (range: 46-88 years) and median Charlson comorbidity index (CCI) was 3. The majority had stage I (70%) and 45% of the tumors were centrally located. The median tumor diameter was 3.8 cm (range: 2-7.6 cm). The mean gross tumor volume was 41 cc (range: 4-139 cc) and the mean planning target volume (PTV) was 141 cc (range: 27-251 cc). Varying dose and fraction (fr) sizes were used depending on tumor location, tumor size, and treatment period. The median biologically effective dose (BED) was 77 Gy₁₀ (range: 77-105 Gy₁₀) for the initial cohort (2007-2012) and 105 Gy₁₀ (range: 77-132 Gy₁₀) for the subsequent cohort (2013-2015).

Results

After a median follow-up of 16 months (range: 3-99 months), the 2-year local control (LC), overall survival, and cancer-specific survival (CSS) rates were 94%, 41%, and 62%, respectively. The univariate and multivariate analysis determined CCI >3 and PTV >80.6 cc as significant predictors of worse OS and CSS (P< 0.01). The clinical stage, tumor location, BED, and treatment period (2007-2012 vs. 2013-2015) did not significantly predict any of the outcomes. The most common acute toxicities were skin erythema (10%), grade 1 esophagitis (8%), and exacerbation of previous chronic obstructive pulmonary disease (10%). Grade ≥2 late radiation pneumonitis was seen in 17.5%. One patient developed a rib fracture. No neurological or vascular complications were seen.

Conclusions

SBRT results in excellent local control (LC) and acceptable survival in medically inoperable ES-NSCLC with minimal adverse effects. Charlson comorbidity index and target volume are important prognostic factors and may aid in patient selection.

Outpatient Anesthesia Facilitates Stereotactic Body Radiation Therapy for Early Stage Lung Cancer Patients With Advanced Cognitive Impairments

Purpose

To report on the use of outpatient anesthesia (OPA) facilitating delivery of stereotactic body radiation therapy (SBRT) in patients with severe cognitive impairments (CI) diagnosed with inoperable early stage lung cancer.

Methods and Materials

We surveyed our institutional review board-approved prospective lung SBRT data registry to document the feasibility of using anesthesia in CI patients and to determine their SBRT outcomes.

Results

From 2004 to 2018, 8 from a total 2084 patients were identified for this analysis. The median age at treatment was 68 years (range, 44-78). Most patients were female (62.5%). CI diagnoses included Alzheimer-related dementia (3 patients), chronic schizophrenia (3 patients), severe anxiety disorder (1 patient), and severe developmental disability (1 patient). The median tumor size was 3.4 cm (range, 1.1-10.5), and 7 patients (87.5 %) had central lesions. The median follow-up time was 22.5 months. The most common (50%) SBRT schedule used was 50 Gy in 5 fractions. Intravenous propofol (10 mg/mL) was used for OPA in all cases at the time of simulation and with daily treatments. OPA was well tolerated and all patients completed SBRT as prescribed. There was one grade 5 but no other grade 3 or higher SBRT-related toxicities. One patient died with local failure and one of distant failure.

Conclusions

OPA made lung SBRT feasible for patients with CIs. SBRT outcomes were in keeping with those reported in the literature. CI should not be considered a contraindication per se to SBRT delivery in patients otherwise appropriate for this modality.

Survival Outcomes of Treatment with Radiofrequency Ablation, Stereotactic Body Radiotherapy, or Sublobar Resection for Patients with Clinical Stage I Non-Small-Cell Lung Cancer: A Single-Center Evaluation

PURPOSE

To retrospectively compare the outcomes of radiofrequency (RF) ablation, stereotactic body radiotherapy (SBRT), and sublobar resection (SLR) in patients with stage I non-small-cell lung cancer (NSCLC) at a single center.

MATERIALS AND METHODS

Overall, 289 patients (38 RF ablation, 58 SBRT, and 193 SLR) were included. Kaplan-Meier curves were generated, multiple propensity score was estimated using a multinomial logistic regression model, and relationships between treatments and outcomes were assessed using a Cox proportional hazard model. Hazard ratios (HRs) for death from any cause and disease progression or death from any cause were examined by a crude model, an inverse probability of treatment weighting (IPTW) model, and an IPTW model adjusted for missing variables.

RESULTS

The 5-year overall and progression-free survival rates were 58.9% and 39.9%, respectively, for RF ablation; 42.0% and 34.9%, respectively, for SBRT; and 85.5% and 75.9%, respectively, for SLR. Significantly longer survival time and lower HR were observed for SLR than other treatments. However, after statistical adjustment, these relationships were not significant except for reduced HR of disease progression or death from any cause of SLR compared to RF ablation in the IPTW model. The median hospital stays for RF ablation, SBRT, and SLR were 6.5, 6, and 16 days, respectively. Adverse events of grade 3 or higher occurred only in 11 SLR cases.

CONCLUSIONS

SLR achieved the longest survival. However, after statistical adjustment, there were no significant outcome differences among RF ablation, SBRT, and SLR, except for 1 model. RF ablation or SBRT may be alternative treatments for selected patients with early-stage NSCLC.

Alternatives to Surgery for Early-Stage Non-Small Cell Lung Cancer: Stereotactic Radiotherapy

Lung cancer is the leading cause of cancer death worldwide. Diagnosis of early-stage disease is becoming more common. In an aging population, more and more patients have substantial comorbidities that might limit feasibility of surgical management of early-stage disease. Stereotactic body radiotherapy (SBRT) enables delivery of high-dose, precisely delivered radiation to early-stage lung cancers without surgical risk. This technique has rates of local control similar to surgery and can be considered in medically operable patients who refuse surgery. This article details the technique of SBRT, the data for its efficacy, as well as the potential toxicities of treatment.

Evaluation of dose distribution differences from five algorithms implemented in three commercial treatment planning systems for lung SBRT

Early stage lung cancer is increasingly being treated using stereotactic body radiation therapy (SBRT). Several advanced treatment planning algorithms are now available in various commercial treatment planning systems. This work compares the dose distributions calculated for the same treatment plan using, five algorithms, in three different treatment planning systems. All plans were normalized to ensure the prescription dose covers 95% of the planning target volume (PTV). Dose to the planning target volume (PTV) was compared using near-minimum dose (D_98%), near-maximum dose (D_2%) and dose homogeneity, while dose fall-off was compared using D_2cm and R₅₀. Dose to the lung was compared using V_5Gy, V_20Gy and mean lung dose. Statistical analysis shows that dose distributions calculated using Eclipse's Acuros XB and RayStation's Monte Carlo were significantly different from the other dose distributions for the PTV dose parameters investigated. For lung dosimetric parameters, this difference persisted for volumetric modulated arc therapy (VMAT) plans but not for conformal arc plans. While normal tissue complication probability (NTCP) differences were significant for some of the algorithms for VMAT delivery approaches, they were not significantly different for any algorithm for conformal arc plans. All parameters investigated here were within 5% between all algorithms. The results show that, while some small dosimetric differences can be expected around the PTV, the dose distribution to the rest of the treatment area, especially the lungs, should not be clinically-relevant when switching between one of the five algorithms investigated.

Establishing the Impact of Vascular Damage on Tumor Response to High-Dose Radiation Therapy

Approximately half of all patients with cancer receive radiotherapy, which is conventionally delivered in relatively small doses (1.8-2 Gy) per daily fraction over one to two months. Stereotactic body radiation therapy (SBRT), in which a high daily radiation dose is delivered in 1 to 5 fractions, has improved local control rates for several cancers. However, despite the widespread adoption of SBRT in the clinic, controversy surrounds the mechanism by which SBRT enhances local control. Some studies suggest that high doses of radiation (≥10 Gy) trigger tumor endothelial cell death, resulting in indirect killing of tumor cells through nutrient depletion. On the other hand, mathematical models predict that the high radiation dose per fraction used in SBRT increases direct tumor cell killing, suggesting that disruption of the tumor vasculature is not a critical mediator of tumor cure. Here, we review the application of genetically engineered mouse models to radiosensitize tumor cells or endothelial cells to dissect the role of these cellular targets in mediating the response of primary tumors to high-dose radiotherapy in vivo These studies demonstrate a role for endothelial cell death in mediating tumor growth delay, but not local control following SBRT.

Chest wall pain following lung stereotactic body radiation therapy using 48Gy in three fractions: A search for predictors

PURPOSE

Chest wall pain is an uncommon but bothersome late complication following lung stereotactic body radiation therapy. Despite numerous studies investigating predictors of chest wall pain, no clear consensus has been established for a chest wall constraint. The aim of our study was to investigate factors related to chest wall pain in a homogeneous group of patients treated at our institution.

PATIENTS AND METHODS

All 122 patients were treated with the same stereotactic body radiation therapy regimen of 48Gy in three fractions, seen for at least 6 months of follow-up, and planned with heterogeneity correction. Chest wall pain was scored according to the Common Terminology Criteria for Adverse Events classification v3.0. Patient (age, sex, diabetes, osteoporosis), tumour (planning target volume, volume of the overlapping region between planning target volume and chest wall) and chest wall dosimetric parameters (volumes receiving at least 30, 40, and 50Gy, the minimal doses received by the highest irradiated 1, 2, and 5cm³, and maximum dose) were collected. The correlation between chest wall pain (grade 2 or higher) and the different parameters was evaluated using univariate and multivariate logistic regression.

RESULTS

Median follow-up was 18 months (range: 6-56 months). Twelve patients out of 122 developed chest wall pain of any grade (seven with grade 1, three with grade 2 and two with grade 3 pain). In univariate analysis, only the volume receiving 30Gy or more (P=0.034) and the volume of the overlapping region between the planning target volume and chest wall (P=0.038) significantly predicted chest wall pain, but these variables were later proved non-significant in multivariate regression.

CONCLUSION

Our analysis could not find any correlation between the studied parameters and chest wall pain. Considering our present study and the wide range of differing results from the literature, a reasonable conclusion is that a constraint for chest wall pain is yet to be defined.

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.

Stereotactic body radiation therapy in early-stage NSCLC: historical review, contemporary evidence and future implications

Clinical use of stereotactic body radiation therapy (SBRT) has increased dramatically over the last 2 decades and is the current standard-of-care in cases of inoperable early stage non-small-cell lung cancer. While surgical resection remains the standard-of-care for operable patients, several ongoing clinical trials are investigating the role of SBRT in these operative candidates as well. Taking into consideration the expanding role and utility of SBRT, this paper will: review the historical basis of SBRT; examine landmark trials establishing the framework for the current body of evidence; discuss areas of active and future research; and identify epidemiological trends that are likely to further increase the use of SBRT.

Phase I/II trial of Durvalumab plus Tremelimumab and stereotactic body radiotherapy for metastatic head and neck carcinoma

BACKGROUND

The efficacy of immunotherapy targeting the PD-1/PD-L1 pathway has previously been demonstrated in metastatic head and neck squamous cell carcinoma (HNSCC). Stereotactic Body Radiotherapy (SBRT) aims at ablating metastatic lesions and may play a synergistic role with immunotherapy. The purpose of this study is to assess the safety and efficacy of triple treatment combination (TTC) consisting of the administration of durvalumab and tremelimumab in combination with SBRT in metastatic HNSCC.

METHOD

This is a phase I/II single arm study that will include 35 patients with 2-10 extracranial metastatic lesions. Patients will receive durvalumab (1500 mg IV every 4 weeks (Q4W)) and tremelimumab (75 mg IV Q4W for a total of 4 doses) until progression, unacceptable toxicity or patient withdrawal. SBRT to 2-5 metastases will be administered between cycles 2 and 3 of immunotherapy. The safety of the treatment combination will be evaluated through assessment of TTC-related toxicities, defined as grade 3-5 toxicities based on Common Terminology Criteria for Adverse Events (v 4.03), occurring within 6 weeks from SBRT start, and that are definitely, probably or possibly related to the combination of all treatments. We hypothesize that dual targeting of PD-L1 and CTLA-4 pathways combined with SBRT will lead to < 35% grade 3-5 acute toxicities related to TTC. Progression free survival (PFS) will be the primary endpoint of the phase II portion of this study and will be assessed with radiological exams every 8 weeks using the RECIST version 1.1 criteria.

DISCUSSION

The combination of synergistic dual checkpoints inhibition along with ablative radiation may significantly potentiate the local and systemic disease control. This study constitutes the first clinical trial combining effects of SBRT with dual checkpoint blockade with durvalumab and tremelimumab in the treatment of metastatic HNSCC. If positive, this study would lead to a phase III trial testing this treatment combination against standard of care in metastatic HNSCC.

TRIAL REGISTRATION

NCT03283605 . Registration date: September 14, 2017; version 1.

Effect of Tumor Location and Dosimetric Predictors for Chest Wall Toxicity in Single-Fraction Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer

PURPOSE

Dosimetric parameters to limit chest wall toxicity (CWT) are not well defined in single-fraction (SF) stereotactic body radiation therapy (SBRT) phase 2 trials. We sought to determine the relationship of tumor location and dosimetric parameters with CWT for SF-SBRT.

METHODS AND MATERIALS

From a prospective registry of 1462 patients, we identified patients treated with 30 Gy or 34 Gy. Gross tumor volume was measured as abutting, ≤1 cm, 1 to 2 cm, or >2 cm from the chest wall. CWT was prospectively graded according to Common Terminology Criteria for Adverse Events version 3.0, with grade 2 requiring medical therapy, grade 3 requiring procedural intervention, and grade 4 being disabling pain. Grade 1 CWT or radiographic rib fracture was not included. Logistic regression analysis was used to identify the parameters associated with CWT and calculate the probability of CWT with dose.

RESULTS

This study included 146 lesions. The median follow-up time was 23.8 months. The 5-year local control, distant metastasis, and overall survival rates were 91.8%, 19.2%, and 28.7%, respectively. Grade 2 to 4 CWT was 30.6% for lesions abutting the chest wall, 8.2% for ≤1 cm from the chest wall, 3.8% for 1 to 2 cm from the chest wall, and 5.7% for >2 cm from the chest wall. Grade ≥3 CWT was 1.4%. Tumor abutment (odds ratio [OR]: 6.5; P = .0005), body mass index (OR: 1.1; P = .02), rib D1cc (OR: 1.01/Gy; P = .03), chest wall D1cc (OR: 1.08/Gy; P = .03), and chest wall D5cc (OR: 1.10/Gy; P = .01) were significant predictors for CWT on univariate analysis. Tumor abutment was significant for CWT (OR: 7.5; P = .007) on multivariate analysis. The probability of CWT was 15% with chest wall D5cc at 27.2 Gy and rib D1cc at 30.2 Gy.

CONCLUSIONS

The rate of CWT with SF-SBRT is similar to the rates published for fractionated SBRT, with most CWT being low grade. Tumor location relative to the chest wall is not a contraindication to SF-SBRT, but the rates increase significantly with abutment. Rib D1cc and chest wall D1cc and D5cc may be used as predictors of CWT.

Chest Wall Toxicity After Stereotactic Body Radiation Therapy: A Pooled Analysis of 57 Studies

PURPOSE

The significance of clinical and dosimetric risk factors in relation to chest wall (CW) injury after stereotactic body radiation therapy (SBRT) for lung tumors were analyzed through a meta-analysis of 57 published studies.

METHODS AND MATERIALS

Studies related to CW injury after lung SBRT were obtained through searching PubMed, Embase, and Cochrane electronic databases. An estimate of the incidence of CW pain (CWP) or rib fracture (RF) was derived using a Bayesian hierarchical model. Linear regression analysis was performed to assess the relationship between CWP or RF and clinical or dosimetric factors.

RESULTS

A total of 57 studies incorporating 5985 cases reporting clinical data on CW injury after SBRT were analyzed. The overall CWP and RF rates by Bayesian hierarchical modeling were 11.0% (95% confidence interval [CI], 8.0-14.4) and 6.3% (95% CI, 3.7-9.7), respectively. The rates of grade ≥2 and grade ≥3 CWP were 6.2% (95% CI, 3.88-8.93) and 1.2% (95% CI, 0.48-2.12), respectively. Sex was significantly correlated with RF (P < .001), with female patients having a greater risk of RF than male patients (hazard ratio = 0.59; 95% CI, 0.46-0.76). No correlation was found between RF, grade ≥2 CWP, or grade ≥3 CWP, with the clinical and dosimetric factors of age, tumor size, origin of lung tumor, gross tumor volume, planning target volume, fractional dose, number of fractions, or biologically effective dose. However, tumor to CW distance (<16-25 mm), body mass index, maximum dose (Dmax) of 0.5 to 5 cm³, and the volume of CW or ribs receiving >30 Gy were significantly associated with CWP and RF.

CONCLUSIONS

The overall rates of RF and grade ≥2 CWP after thoracic SBRT are relatively low. Sex, tumor to CW distance, maximum dose, and the radiation exposure of the CW or ribs are factors associated with the risk of CW toxicity after SBRT.

Comparison Between Stereotactic Radiotherapy and Sublobar Resection for Non-Small Cell Lung Cancer

BACKGROUND

The aim of this study was to compare outcomes of primary treatment with stereotactic body radiation therapy (SBRT) versus sublobar resection (SLR) for clinical stage I non-small cell lung cancer (NSCLC) in patients with medical comorbidities.

METHODS

Consecutive patients who underwent SBRT (n = 106) or SLR (100 wedge resection, 41 segmentectomy) because of medical comorbidities associated with stage I NSCLC were enrolled. Lesions located in the outer third of the lung field on computed tomography were defined as external, and others were defined as internal. A propensity score-matched analysis was also performed that compared SBRT and SLR results. Charts were reviewed to determine local tumor recurrence, disease-specific survival (DSS), and overall survival (OS).

RESULTS

A propensity score-matched analysis, recurrence-free survival (RFS) became significant in favor of surgery (p = 0.036). For large nodules of greater than 2.0 cm in diameter, RFS was significantly better in the surgery group (p = 0.042). No significant differences in OS, DSS, or RFS were observed with small nodules of less than 2.0 cm in diameter. In the external group, a higher recurrence rate was seen for SBRT group. For internal group, there was no statistical difference between each treatment. Local recurrence rate was higher in the SBRT group (p = 0.0082) in the external group.

CONCLUSIONS

In a matched comparison of stage I NSCLC in patients with medical comorbidities, RFS was in favor of surgery comparing SBRT, but there were no significant differences in OS or DSS. The tumor size and tumor location should be considered before deciding whether to perform SBRT or surgery.

Comorbidity indexing for prediction of the clinical outcome after stereotactic body radiation therapy in non-small cell lung cancer

Purpose

To determine the prognostic impact of comorbidity and age in medically inoperable early-stage non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT) using the age-adjusted Charlson Comorbidity Index (aCCI).

Patients and methods

Between November 2008 and January 2015, 196 consecutive patients with medically inoperable NSCLC were treated with SBRT at a single institution. The prescribed isocenter dose was either 60.0 Gray (Gy) in six fractions for central lung cancer or 56.25 Gy in three fractions for peripheral lung cancer. Baseline comorbidities were retrospectively retrieved according to available outclinic medical records as well as the hospital information system. The aCCI was scored for each patient and subjected according to outcome and toxicity as well as all of the single items of the aCCI and other clinical parameters using univariate and multivariate analysis.

Results

Thirty-one point 6 % (62/196) of patients were deceased, of whom 17.3% (34/196) died due to lung cancer and 14.3% (28/196) due to comorbidities. The median overall survival (OS) was 15.0 months (95% CI [11.9–18.1]), whereas the median cancer-specific survival (CSS) was not reached. An aCCI ≥7 compared with an aCCI ≤6 was significantly associated with an increased risk of death (HR 1.79, 95% CI [1.02–2.80], p = 0.04) and cancer-specific death (HR 9.26, 95% CI [4.83–24.39], p < 0.001), respectively. Neither OS nor CCS were significantly associated with age, sex, side (left vs. right), lobe, localization (central vs. peripheral), packyears, TNM, or any item of the aCCI. Considering the 14.3% (28/196) of deceased patients who died due to comorbidities, aCCI ≥9 was significantly associated with non-cancer-related death (HR 3.12, 95% CI [1.22–8.33], p = 0.02). The observed cumulative rate of radiation pneumonitis (RP) ≥2 was 12.7% (25/196). The aCCI had no statistical association with RP.

Conclusion

Advanced age and numerous comorbidities characterizing this patient population were successfully assessed using the aCCI in terms of survival. Therefore, we recommend that age and comorbidity be indexed using the aCCI as a simple scoring system for all patients treated with SBRT for lung cancer.

Early stage lung cancer survival after wedge resection and stereotactic body radiation

BACKGROUND

The comparative effectiveness of stereotactic body radiation therapy (SBRT) and wedge resection in the treatment of early stage lung cancer is still under debate. This meta-analysis compares the 5-year overall survival (OS) of wedge resection and SBRT in patients with stage I non-small cell lung cancer (NSCLC).

METHODS

Original research articles published between 1995 and 2017 were identified through the National Library of Medicine and National Institutes of Health PubMed database and through the reference lists of reviewed articles. Data were processed and analyzed in R (version 3.4.2) and a summary estimate that accounted for the sample size of each study was calculated. The combined percent survival was calculated using random effect models. Funnel plots were used to assess publication bias. Heterogeneity was tested using the Q statistic and the I2 statistic.

RESULTS

There were 16 studies totaling 1,984 patients with stage I NSCLC treated with wedge resection. The meta-estimate was 74% (95% CI, 66-81%), with significant heterogeneity across studies (Q =172.46, P<0.0001; I2=91.30%). Thirty-six studies including 3,309 patients with stage I NSCLC treated with SBRT/SABR produced a meta-estimate of 44% (95% CI, 38-50%), with significant heterogeneity (Q =423.55, P<0.0001; I2=91.74%). Two articles directly comparing stage I NSCLC patients treated with wedge resection to patients treated with SBRT both reported higher 5-year OS after wedge resection.

CONCLUSIONS

SBRT is a treatment option reserved to medically inoperable patients, but could be an alternative to surgery in medically operable patients who prefer a less invasive treatment. More standardized methods for data collection and reporting are necessary to allow better comparisons across published studies.

Stereotactic Body Radiation Therapy for Biopsy-Proven Primary Non-Small-Cell Lung Cancer: Experience of Patients With Inoperable Cancer at a Single Brazilian Institution

Purpose

Stereotactic body radiation therapy (SBRT) has emerged as a treatment option for patients with non–small-cell lung cancer (NSCLC). We report the clinical outcomes and toxicity for patients with inoperable primary NSCLC treated with SBRT.

Methods

Between 2007 and 2015, 102 consecutive lung lesions were treated with SBRT at our center, of which 59 primary NSCLC lesions (from 54 patients with inoperable disease) were retrospectively reviewed (43 lesions were excluded because of metastases or because there was no biopsy specimen). We report infield local control (LC) per SBRT target, regional or distant failure-free survival, and overall survival (OS) per patient, using Kaplan-Meier estimates. Serious toxicity was retrospectively scored using Common Terminology Criteria for Adverse Events, version 4.

Results

Most of the 54 patients were men (n = 41; 76%), median age was 75 years; stage IA (n = 36; 66%) and adenocarcinoma (n = 43; 80%) were the most common stage and histologic diagnosis, respectively. Five patients had two lung lesions. A median of three fractions (range, 3 to 5 fractions) and a total median dose of 54 Gy (range, 45 to 60 Gy) per lesion were prescribed. The median follow-up was 17.8 months (range, 4 to 56.4 months). The 2-year rates of LC, regional or distant failure-free survival, and OS were 89.1% (95% CI, 72.2% to 96%), 79% (95% CI, 59.8% to 89.8%), and 80% (95% CI, 64% to 89.8%), respectively. Grade 3 to 4 toxicities were observed in two patients (3%): grade 3 pneumonitis (n = 1) and grade 4 skin toxicity (n = 1).

Conclusion

SBRT results in high rates of 2-year LC, regional or distant failure-free survival, and OS with low rates of severe toxicity in patients with inoperable primary NSCLC disease.

30 Gy single dose stereotactic body radiation therapy (SBRT): Report on outcome in a large series of patients with lung oligometastatic disease

OBJECTIVES

To evaluate the local control (LC) and long term adverse effects in a series of patients with lung metastases who received 30 Gy in single dose with stereotactic technique.

MATERIALS AND METHODS

Between December 2008 and April 2016, a total of 166 lung metastases in 129 patients affected by oligometastatic disease were treated at our Institution with stereotactic body radiotherapy (SBRT). Mainly, the primary tumors were non small-cell lung cancer and colorectal cancer (45.2% and 28.8%, respectively). Prognostic factors were also assessed.

RESULTS

The median follow-up was 38 months. Local progression occurred in 24 (14.4%) lesions in 21 patients. Intra-thoracic progression (new lung lesions or thoracic lymph node metastases) occurred in 59 (45.7%) patients. Forty-five (34.8%) patients had distant progression after a median time of 14 months. The 3- and 5-years local relapse-free survival (LPFS) were 80.1% and 79.2% (median not reached), respectively. One-hundred forty-eight patients were evaluated for late toxicity (follow-up >6 months): 51 (34.4%) patients had grade ≤2 fibrosis, 11 (7.4%) patients experienced grade 3 fibrosis. Two (1.3%) cases of rib fracture occurred. One case of toxic death (grade 5) has been reported. Median OS was 39 months. At the univariate analysis, lesion diameter ≤18 mm correlated significantly with a longer LPFS (p = 0.001). At the multivariate analysis, lesion diameter <18 mm was predictive for longer LPFS (p = 0.006). Also, oligometastases from primary colorectal cancer was a significant predictive factor for worse LPFS (p = 0.041) and progression-free survival (p = 0.04).

CONCLUSIONS

To our knowledge, the current study represents the largest series on the use of SBRT 30 Gy single dose for lung metastases. Our results confirm the effectiveness and safety of this schedule administered in selected oligometastatic patients. Further prospective series could better validate these results.

Three- Versus Five-Fraction Regimens of Stereotactic Body Radiotherapy for Peripheral Early-Stage Non-Small-Cell Lung Cancer: A Two-Institution Propensity Score-Matched Analysis

PURPOSE

To evaluate differences in outcomes of early-stage peripheral non-small-cell lung cancer (NSCLC) treated with either 3- or 5-fraction stereotactic body radiotherapy (SBRT) at 2 institutions.

PATIENTS AND METHODS

Patients diagnosed with peripherally located early-stage NSCLC who received either a median dose of 60 Gy (interquartile range [IQR], 60-60, biologically effective dose, 151-151) in 3 fractions or a median dose of 50 Gy (IQR, 50-50, biologically effective dose, 94-94) in 5 fractions were included in this study. All data were retrospectively collected and reviewed in an institutional review board-approved database.

RESULTS

A total of 192 lesions in 192 patients were identified: 94 received 3-fraction SBRT and 98 received 5-fraction SBRT. Patients in the 5-fraction cohort had significantly smaller tumors (P = .0021). Larger tumor size was associated with worse overall survival (hazard ratio, 1.40, P = .0013) for all patients. A single grade 3 toxicity was reported in each cohort. A propensity score-matched cohort of 94 patients was constructed with a median follow-up of 29.3 months (IQR, 17.3-44.6) for the 3-fraction cohort and 31.0 months (IQR, 17.0-48.5) for the 5-fraction cohort (P = .84). There were no statistically significant differences between these 2 cohorts in overall survival (P = .33), progression-free survival (P = .40), local failure (P = .86), and nodal or distant failure (P = .57) at 2 years.

CONCLUSION

The 3- and 5-fraction SBRT regimens for early-stage peripheral NSCLC had comparable clinical outcomes. Both regimens were well tolerated. A large tumor size was an adverse prognostic factor for worse survival.

Comparison of Single- and Three-fraction Schedules of Stereotactic Body Radiation Therapy for Peripheral Early-stage Non-Small-cell Lung Cancer

BACKGROUND

To compare the clinical outcomes of patients with early-stage non-small-cell lung cancer (NSCLC) who had undergone either single-fraction (SF) or three-fraction (TF) stereotactic body radiation therapy (SBRT) at a single institution during over 8-year period.

PATIENTS AND METHODS

Patients with peripherally located early-stage NSCLC who had undergone SBRT from February 2007 to November 2015 were included in the present study. SBRT was delivered without heterogeneity correction. Data were retrospectively reviewed and collected in an institutional review board-approved database. R software (version 3.3.2) was used for statistical analysis.

RESULTS

Of 159 total lung tumors, 65 lesions received 30 Gy (median, 30 Gy) in 1 fraction, and 94 lesions received 48 to 60 Gy (median, 60 Gy) in 3 fractions. Patients with a Karnofsky performance status < 80 were more common in the SF-SBRT cohort (P = .050). After a median follow-up of 22.2 and 26.2 months for the SF-SBRT and TF-SBRT cohorts, respectively (P = .29), no statistically significant difference was found in overall survival (P = .86), progression-free survival (P = .95), local failure (P = .95), nodal failure (P = .91), and distant failure (P = .49) at 24 months. At 1 and 2 years, the overall survival rates were 86.1% and 63.2% for the SF-SBRT cohort and 80.8% and 61.6% for the TF-SBRT cohort, respectively. At 1 and 2 years, the local control rates were 95.1% and 87.8% for the SF-SBRT cohort and 92.7% and 86.2% for the TF-SBRT cohort, respectively. Both regimens were well tolerated.

CONCLUSION

Despite more patients with poor performance status in the SF-SBRT cohort, the SF- and TF-SBRT regimens showed no differences in clinical outcomes. SF-SBRT is now our standard approach.

Patient-clinician communication among patients with stage I lung cancer

PURPOSE

Limited data exist about patient-centered communication (PCC) and patient-centered outcomes among patients who undergo surgery or stereotactic body radiation therapy (SBRT) for stage I non-small cell lung cancer (NSCLC). We aimed to examine the relationship between PCC and decision-making processes among NSCLC patients, using baseline data from a prospective, multicenter study.

METHODS

Patients with stage 1 NSCLC completed a survey prior to treatment initiation. The survey assessed sociodemographic characteristics, treatment decision variables, and patient psychosocial outcomes: health-related quality of life (HRQOL), treatment self-efficacy, decisional conflict, and PCC.

RESULTS

Fifty-two percent (n = 85) of 165 individuals planned to receive SBRT. There were no baseline differences detected on patient psychosocial outcomes between those who planned to receive SBRT or surgery. All participants reported high HRQOL (M = 72.5, SD = 21.3) out of 100, where higher scores indicate better functioning; high self-efficacy (M = 1.5, SD = 0.5) out of 6, where lower numbers indicate higher self-efficacy; minimal decisional conflict (M = 15.2, SD = 12.7) out of 100, where higher scores indicate higher decisional conflict; and high levels of patient-centered communication (M = 2.4, SD = 0.8) out of 7 where higher scores indicate worse communication. Linear regression analyses adjusting for sociodemographic and clinical variables showed that higher quality PCC was associated with higher self-efficacy (β = 0.17, p = 0.03) and lower decisional conflict (β = 0.42, p < 0.001).

CONCLUSIONS

Higher quality PCC was associated with higher self-efficacy and lower decisional conflict. Self-efficacy and decisional conflict may influence subsequent health outcomes. Therefore, our findings may inform future research and clinical programs that focus on communication strategies to improve these outcomes.

Stereotactic Body Radiation Therapy for Early-Stage Lung Cancer

Stereotactic body radiation therapy (SBRT), also known as stereotactic ablative radiotherapy, is a technique of external beam radiation that delivers precisely targeted, ablative doses to extracranial sites. It has become an integral component of the management of early-stage non-small cell lung cancer (NSCLC). In this review, we discuss the technology and techniques used in treatment planning and delivery, the efficacy and toxicity of SBRT for medically inoperable early-stage NSCLC, and the preliminary investigations into the role of SBRT for operable early-stage NSCLC.

Chronic obstructive pulmonary disease in patients with lung cancer: prevalence, impact and management challenges

Chronic obstructive pulmonary disease (COPD) and lung cancer share a common etiological factor (cigarette smoking) and usually coexist in everyday clinical practice. The prevalence of COPD among newly diagnosed patients with lung cancer sometimes exceeds 50%. COPD is an independent risk factor (2-4 times higher than non-COPD subjects) for lung cancer development. The presence of emphysema in addition to other factors (e.g., smoking history, age) could be incorporated into risk scores in order to define the most appropriate target group for lung cancer screening using low-dose computed tomography. Clinical management of patients with coexistence of COPD and lung cancer requires a multidisciplinary oncology board that includes a pulmonologist. Detailed evaluation (lung function tests, cardiopulmonary exercise test) and management (inhaled drugs, smoking cessation, pulmonary rehabilitation) of COPD should be taken into account for lung cancer treatment (surgical approach, radiotherapy).

Comparison of particle beam therapy and stereotactic body radiotherapy for early stage non-small cell lung cancer: A systematic review and hypothesis-generating meta-analysis

PURPOSE

To assess hypo-fractionated particle beam therapy (PBT)'s efficacy relative to that of photon stereotactic body radiotherapy (SBRT) for early stage (ES) non-small cell lung cancer (NSCLC).

METHODS

Eligible studies were identified through extensive searches of the PubMed, Medline, Google-scholar, and Cochrane library databases from 2000 to 2016. Original English publications of ES NSCLC were included. A meta-analysis was performed to compare the survival outcome, toxicity profile, and patterns of failure following each treatment.

RESULTS

72 SBRT studies and 9 hypo-fractionated PBT studies (mostly single-arm) were included. PBT was associated with improved overall survival (OS; p=0.005) and progression-free survival (PFS; p=0.01) in the univariate meta-analysis. The OS benefit did not reach its statistical significance after inclusion of operability into the final multivariate meta-analysis (p=0.11); while the 3-year local control (LC) still favored PBT (p=0.03).

CONCLUSION

Although hypo-fractionated PBT may lead to additional clinical benefit when compared with photon SBRT, no statistically significant survival benefit from PBT over SBRT was observed in the treatment of ES NSCLC in this hypothesis-generating meta-analysis after adjusting for potential confounding variables.

A systematic review of outcomes following stereotactic ablative radiotherapy in the treatment of early-stage primary lung cancer

Stereotactic ablative body radiotherapy (SABR) describes a radiotherapy (RT) technique where high doses of radiation are precisely delivered to an extracranial target within the body, using either a single fraction of RT or using multiple small numbers of fractions. SABR has now become the standard of care treatment for patients with early-stage non-small-cell lung cancer (NSCLC) for whom surgery is not appropriate. This systematic review considers the evidence supporting the use of SABR in early-stage NSCLC, reported toxicity rates, the use of SABR in centrally located NSCLC, the use of SABR as salvage therapy following surgery or RT, and future potential drug combinations with SABR.

Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer

Stereotactic body radiation therapy (SBRT) has had a profound impact on the treatment paradigm for medically inoperable patients with stage I non-small cell lung cancer. Local control and survival outcomes from prospective collaborative trials using SBRT have been highly favorable in this challenging patient population. Further study in medically operable patients is ongoing; however, randomized trials to help answer this question have terminated early because of poor accrual. Available prospective and retrospective data are discussed for the use of SBRT with regard to the medically inoperable and operable patient populations, as well as considerations for fractionation, dose, and toxicity.

SPACE - A randomized study of SBRT vs conventional fractionated radiotherapy in medically inoperable stage I NSCLC

BACKGROUND

Stereotactic body radiotherapy (SBRT) has been introduced for small lung tumors due to excellent local control and few side effects, even though there are no comparative studies. SPACE (Stereotactic Precision And Conventional radiotherapy Evaluation) is the first randomized phase II trial comparing SBRT and conventional fractionated radiotherapy (3DCRT).

METHODS

Patients with stage I medically inoperable NSCLC were randomized to receive SBRT to 66Gy in 3 fractions (one week) or 3DCRT to 70Gy (7weeks). Patients were followed to assess efficacy, toxicity and HRQL.

FINDINGS

Between 2007 and 2011, 102 patients were randomized. Mean age 74 (57-86), 60% women, the vast majority (92%) had COPD or cardiovascular comorbidity. The SBRT arm included more patients with T2-tumors (p=0.02) and male gender (p=0.35). The median follow-up was 37months with a 1-, 2- and 3-year PFS of: SBRT: 76%, 53%, 42% and 3DCRT: 87%, 54% 42%, HR=0.85 (95% CI 0.52-1.36) with no difference between the groups and no difference in OS (HR=0.75, 95% CI 0.43-1.30). At the end of the study 70% of SBRT patients had not progressed compared to 59% (3DCRT, p=0.26). Toxicity was low with no grade 5 events. Pneumonitis of any grade was observed in 19% (SBRT) and 34% (3DCRT, p=0.26), and esophagitis in 8% and 30% respectively (p=0.006). HRQL was evaluated with the EORTC QLQ 30 and LC14 module and patients treated with 3DCRT experienced worse dyspnea (p=0.01), chest pain (p=0.02) and cough (>10 points difference).

INTERPRETATION

There was no difference in PFS and OS between SBRT and conventionally treated patients despite an imbalance of prognostic factors. We observed a tendency of an improved disease control rate in the SBRT group and they experienced better HRQL and less toxicity. SBRT is convenient for patients and should be considered standard treatment for patients with inoperable stage I NSCLC.

Comparison of the Effectiveness of Radiofrequency Ablation With Stereotactic Body Radiation Therapy in Inoperable Stage I Non-Small Cell Lung Cancer: A Systemic Review and Pooled Analysis

PURPOSE

To performed a systematic review and pooled analysis to compare clinical outcomes of stereotactic body radiation therapy (SBRT) and radiofrequency ablation (RFA) for the treatment of medically inoperable stage I non-small cell lung cancer.

METHODS AND MATERIALS

A comprehensive literature search for published trials from 2001 to 2012 was undertaken. Pooled analyses were performed to obtain overall survival (OS) and local tumor control rates (LCRs) and adverse events. Regression analysis was conducted considering each study's proportions of stage IA and age.

RESULTS

Thirty-one studies on SBRT (2767 patients) and 13 studies on RFA (328 patients) were eligible. The LCR (95% confidence interval) at 1, 2, 3, and 5 years for RFA was 77% (70%-85%), 48% (37%-58%), 55% (47%-62%), and 42% (30%-54%) respectively, which was significantly lower than that for SBRT: 97% (96%-98%), 92% (91%-94%), 88% (86%-90%), and 86% (85%-88%) (P<.001). These differences remained significant after correcting for stage IA and age (P<.001 at 1 year, 2 years, and 3 years; P=.04 at 5 years). The effect of RFA was not different from that of SBRT on OS (P>.05). The most frequent complication of RFA was pneumothorax, occurring in 31% of patients, whereas that for SBRT (grade ≥3) was radiation pneumonitis, occurring in 2% of patients.

CONCLUSIONS

Compared with RFA, SBRT seems to have a higher LCR but similar OS. More studies with larger sample sizes are warranted to validate such findings.

Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer: A Retrospective, Single-Center Study of 55 Patients

Purpose/Objective(s): Stereotactic body radiation therapy (SBRT) is an effective treatment for patients with early-stage non-small cell lung cancer (NSCLC) who are not surgical candidates or who refuse surgical management. In this study, we report on our clinical outcomes and toxicity in the treatment of early-stage NSCLC with SBRT.

METHODS AND MATERIALS

Fifty-five patients with 59 T1-2N0M0 NSCLC lesions were treated at our institution between December 2009 and August 2014. The majority of the patients [38 (69%)] were treated with 50 Gy in 5 fractions, 7 patients (13%) with 48 Gy in 4 fractions, 8 patients (14%) with 60 Gy in 3 fractions, 1 patient (2%) with 62.5 Gy in 10 fractions, and 1 patient (2%) with 54 Gy in 3 fractions. Tumor response was evaluated using RECIST 1.1, and toxicity was graded using the CTCAE (Common Terminology Criteria for Adverse Events) version 3.0. The primary endpoints of this retrospective review included rates of overall survival, disease-free and progression-free survival, local failure, regional failure, and distant failure. A secondary endpoint included radiation-related toxicities.

RESULTS

The median follow-up was 23.8 months (range 1.1-57.6). The 3-year local control, progression-free survival, and overall survival rates were 91, 55, and 71%, respectively. The median age at diagnosis was 67.9 years (range 51.4-87.1). There were a total of 54 T1N0 tumors (92%) and 5 T2N0 lesions (8%). Adenocarcinoma was the most common pathology, comprising 54% of the lesions. A total of 16 of the patients (29%) failed. Among these, 5 local (9%), 14 regional (25%), and 4 distant failures (7%) were observed. On follow-up, one patient had grade 2 and another had grade 5 pneumonitis. Three patients experienced grade 2 chest wall tenderness. Two patients had grade 1 rib fractures, one of which could not be discerned from radiation-induced toxicity versus a traumatic fall.

CONCLUSION

The University of Mississippi Medical Center SBRT experience has shown that SBRT provides satisfactory local control and overall survival rates with minimal toxicity in early-stage NSCLC patients.

Effect of the normalized prescription isodose line on the magnitude of Monte Carlo vs. pencil beam target dose differences for lung stereotactic body radiotherapy

In lung stereotactic body radiotherapy (SBRT) cases, the pencil beam (PB) dose calculation algorithm is known to overestimate target dose as compared to the more accurate Monte Carlo (MC) algorithm. We investigated whether changing the normalized prescription isodose line affected the magnitude of MC vs. PB target dose differences. Forty‐eight patient plans and twenty virtual‐tumor phantom plans were studied. For patient plans, four alternative plans prescribed to 60%, 70%, 80%, and 90% isodose lines were each created for 12 patients who previously received lung SBRT treatments. Using 6 MV dynamic conformal arcs, the plans were individually optimized to achieve similar dose coverage and conformity for all plans of the same patient, albeit at the different prescription levels. These plans, having used a PB algorithm, were all recalculated with MC to compare the target dose differences. The relative MC vs. PB target dose variations were investigated by comparing PTV D95, Dmean, and D5 loss at the four prescription levels. The MC‐to‐PB ratio of the plan heterogeneity index (HI) was also evaluated and compared among different isodose levels. To definitively demonstrate the cause of the isodose line dependence, a simulated phantom study was conducted using simple, spherical virtual tumors planned with uniform block margins. The tumor size and beam energy were also altered in the phantom study to investigate the interplay between these confounding factors and the isodose line effect. The magnitude of the target dose overestimation by PB was greater for higher prescription isodose levels. The MC vs. PB reduction in the target dose coverage indices, D95 and V100 of PTV, were found to monotonically increase with increasing isodose lines from 60% to 90%, resulting in more pronounced target dose coverage deficiency at higher isodose prescription levels. No isodose level‐dependent trend was observed for the dose errors in the target mean or high dose indices, Dmean or D5. The phantom study demonstrated that the observed isodose level dependence was caused by different beam margins used for the different isodose levels: a higher prescription line required a larger beam margin, leading to more low‐density lung tissues in the field and, therefore, larger dose errors at the target periphery (when calculated with PB). The phantom study also found that the observed isodose level dependence was greater for smaller targets and for higher beam energies. We hereby characterized the effect of normalized prescription isodose line on magnitude of PTV dose coverage as calculated by MC vs. PB. When comparing reported MC dose deficiency values for different patients, the selection of prescription isodose line should be considered in addition to other factors known to affect differences in calculated doses between various algorithms.

PACS number(s): 87.55.kh, 87.55.dk, 87.55.de

Improving Delivery Accuracy of Stereotactic Body Radiotherapy to a Moving Tumor Using Simplified Volumetric Modulated Arc Therapy

PURPOSE

To develop a simplified volumetric modulated arc therapy (VMAT) technique for more accurate dose delivery in thoracic stereotactic body radiation therapy (SBRT).

METHODS AND MATERIALS

For each of the 22 lung SBRT cases treated with respiratory-gated VMAT, a dose rate modulated arc therapy (DrMAT) plan was retrospectively generated. A dynamic conformal arc therapy plan with 33 adjoining coplanar arcs was designed and their beam weights were optimized by an inverse planning process. All sub-arc beams were converted into a series of control points with varying MLC segment and dose rates and merged into an arc beam for a DrMAT plan. The plan quality of original VMAT and DrMAT was compared in terms of target coverage, compactness of dose distribution, and dose sparing of organs at risk. To assess the delivery accuracy, the VMAT and DrMAT plans were delivered to a motion phantom programmed with the corresponding patients' respiratory signal; results were compared using film dosimetry with gamma analysis.

RESULTS

The plan quality of DrMAT was equivalent to that of VMAT in terms of target coverage, dose compactness, and dose sparing for the normal lung. In dose sparing for other critical organs, DrMAT was less effective than VMAT for the spinal cord, heart, and esophagus while being well within the limits specified by the Radiation Therapy Oncology Group. Delivery accuracy of DrMAT to a moving target was similar to that of VMAT using a gamma criterion of 2%/2mm but was significantly better using a 2%/1mm criterion, implying the superiority of DrMAT over VMAT in SBRT for thoracic/abdominal tumors with respiratory movement.

CONCLUSION

We developed a DrMAT technique for SBRT that produces plans of a quality similar to that achieved with VMAT but with better delivery accuracy. This technique is well-suited for small tumors with motion uncertainty.

Ablative dose proton beam therapy for stage I and recurrent non-small cell lung carcinomas : Ablative dose PBT for NSCLC

PURPOSE

To evaluate the efficacy and safety of ablative dose hypofractionated proton beam therapy (PBT) for patients with stage I and recurrent non-small cell lung carcinoma (NSCLC).

PATIENTS AND METHODS

A total of 55 patients with stage I (n = 42) and recurrent (n = 13) NSCLC underwent hypofractionated PBT and were retrospectively reviewed. A total dose of 50-72 CGE (cobalt gray equivalent) in 5-12 fractions was delivered.

RESULTS

The median follow-up duration was 29 months (range 4-95 months). There were 24 deaths (43.6%) during the follow-up period: 11 died of disease progression and 13 from other causes. Kaplan-Meier overall survival rate (OS) at 3 years was 54.9% and the median OS was 48.6 months (range 4-95 months). Local progression was observed in 7 patients and the median time to local progression was 9.3 months (range 5-14 months). Cumulative actuarial local control rate (LCR), lymph node metastasis-free survival, and distant metastasis-free survival rates at 3 years were 85.4, 78.4, and 76.5%, respectively. Larger tumor diameter was significantly associated with poorer LCR (3-year: 94% for ≤3 cm vs. 65% for >3 cm, p = 0.006) on univariate analysis and also an independent prognostic factor for LCR (HR 6.9, 95% CI = 1.3-37.8, p = 0.026) on multivariate analysis. No grade 3 or 4 treatment-related toxicities developed. One grade 5 treatment-related adverse event occurred in a patient with symptomatic idiopathic pulmonary fibrosis.

CONCLUSIONS

Ablative dose hypofractionated PBT was safe and promising for stage I and recurrent NSCLC.

A forward planned treatment planning technique for non-small-cell lung cancer stereotactic ablative body radiotherapy based on a systematic review of literature

Purpose and Method

A systematic literature review of six computerised databases was undertaken in order to review and summarise a forward planned lung stereotactic ablative body radiotherapy (SABR) treatment planning (TP) technique as a starting point for clinical implementation in the author’s department based on current empirical research. The data were abstracted and content analysed to synthesise the findings based upon a SIGN quality checklist tool.

Findings

A four-dimensional computed tomography scan should be performed upon which the internal target volume and organs at risk (OAR) are drawn. A set-up margin of 5 mm is applied to account for inter-fraction motion. The field arrangement consists of a combination of 7–13 coplanar and non-coplanar beams all evenly spaced. Beam modifiers are used to assist in the homogeneity of the beam, although a 20% planning target volume dose homogeneity is acceptable. The recommended fractionations by the UK SABR Consortium are 54 Gy in 3 fractions (standard), 55–60 Gy in 5 fractions (conservative) and 50–60 Gy in 8–10 fractions (very conservative). Conformity indices for both the target volume and OAR will be used to assess the planned distribution.

Conclusion

An overview of a clinically acceptable forward planned lung SABR TP technique based on current literature as a starting point, with a view to inverse planning with support from the UK SABR Consortium mentoring scheme.

Efficacy and Safety of Stereotactic Ablative Radiotherapy in Patients with Previous Pneumonectomy

Background

Thoracic surgery for a newly diagnosed primary lung tumor following a previous pneumonectomy is rarely indicated. Stereotactic ablative radiotherapy (SABR) might represent a curative option. This report focuses on outcomes, toxicity and quality of life (QoL) after SABR.

Methods

Nine patients were treated with SABR between 2004 and 2011; median time since surgery was 8.4 years. In 4 cases, a histological confirmation was possible with bronchoscopy. In 5 cases, the clinical proof of malignancy was based on radiological criteria. Forced expiratory volume in 1 second (FEV1) and diffusing capacity of the lung for carbon monoxide (DLCO) were tested in all patients. A SABR biologically equivalent dose of >100 Gy was prescribed in all cases. QoL questionnaire forms were administered before SABR and during follow-up.

Results

Median follow-up was 41.8 months. We did not observe grade >3 acute toxicity, and concerning late toxicity, we registered 2 cases. QoL was decreased during the first 12 months of follow-up, followed by a progressive improvement after this time. One patient had a local relapse at 7.4 years; 1 developed a new nodule at 5.5 years, associated with metastases; and 1 developed a new nodule without any systemic disease at 3 years. There were 2 cancer-related deaths (18.2%) at 3 and 12 months after progression.

Conclusions

Data support efficacy and safety of SABR in patients with a new primary lung cancer following previous pneumonectomy, with acceptable acute, late toxicity profile and without significant impairment of QoL. Our results were comparable to those in the literature.

Minimal Inter-Fractional Fiducial Migration during Image-Guided Lung Stereotactic Body Radiotherapy Using SuperLock Nitinol Coil Fiducial Markers

Objectives

Stereotactic body radiotherapy (SBRT) is being increasingly used for the treatment of patients with lung cancer or lung metastasis who are medically unfit to undergo resection. In order to improve accuracy and confidence in targeting tumors, many centers rely on fiducial implantation. We evaluated the migration of a novel fiducial marker specifically designed for lung tissue implanted via electromagnetic navigation bronchoscopy (ENB).

Methods

We retrospectively quantified the individual and group migrations of SuperLock nitinol coil fiducials for 15 patients receiving lung stereotactic body radiotherapy (SBRT), in order to evaluate the reliability of using these fiducials as a target surrogate for cases where tumors cannot be clearly delineated on cone beam CTs (CBCTs). For each fraction, we compared the individual and group migrations of the fiducials between the planning CT and the acquired CBCT. The group migration was defined as the distance between the centroids of the fiducial group and GTV.

Results

A total of 16 lung targets were included in our study for these 15 patients (one patient with two targets). Of 55 fiducials placed, we observed a 100% retention rate. The mean individual migration was 1.87 mm (range, 0.63–5.25 mm) with a standard deviation of 1.26 mm. The mean group migration was 1.94 mm (range, 0.03–6.19 mm) with a standard deviation of 1.45 mm. Overall, there was minimal change in the relative locations of the markers with respect to each other, as well as to the target.

Conclusions

We found that the SuperLock nitinol coil fiducial marker positions are stable throughout the radiation treatment, and can be used as a reliable surrogate to target, and to avoid geometric misses during gated treatments.

Effect of stereotactic dosimetric end points on overall survival for Stage I non-small cell lung cancer: a critical review

Stereotactic body radiation therapy (SBRT) delivers a high biologically effective dose while minimizing toxicities to surrounding tissues. Within the scope of clinical trials and local practice, there are inconsistencies in dosimetrics used to evaluate plan quality. The purpose of this critical review was to determine if dosimetric parameters used in SBRT plans have an effect on local control (LC), overall survival (OS), and toxicities. A database of relevant trials investigating SBRT for patients with early-stage non-small cell lung cancer was compiled, and a table of dosimetric variables used was created. These parameters were compared and contrasted for LC, OS, and toxicities. Dosimetric end points appear to have no effect on OS or LC. Incidences of rib fractures correlate with a lack of dose-volume constraints (DVCs) reported. This review highlights the great disparity present in clinical trials reporting dosimetrics, DVCs, and toxicities for lung SBRT. Further evidence is required before standard DVCs guidelines can be introduced. Dosimetric end points specific to stereotactic treatment planning have been proposed but require further investigation before clinical implementation.

Monte Carlo Calculation of Radioimmunotherapy with (90)Y-, (177)Lu-, (131)I-, (124)I-, and (188)Re-Nanoobjects: Choice of the Best Radionuclide for Solid Tumour Treatment by Using TCP and NTCP Concepts

Radioimmunotherapy has shown that the use of monoclonal antibodies combined with a radioisotope like ¹³¹I or ⁹⁰Y still remains ineffective for solid and radioresistant tumour treatment. Previous simulations have revealed that an increase in the number of ⁹⁰Y labelled to each antibody or nanoobject could be a solution to improve treatment output. It now seems important to assess the treatment output and toxicity when radionuclides such as ⁹⁰Y, ¹⁷⁷Lu, ¹³¹I, ¹²⁴I, and ¹⁸⁸Re are used. Tumour control probability (TCP) and normal tissue complication probability (NTCP) curves versus the number of radionuclides per nanoobject were computed with MCNPX to evaluate treatment efficacy for solid tumours and to predict the incidence of surrounding side effects. Analyses were carried out for two solid tumour sizes of 0.5 and 1.0 cm radius and for nanoobject (i.e., a radiolabelled antibody) distributed uniformly or nonuniformly throughout a solid tumour (e.g., Non-small-cell-lung cancer (NSCLC)). ⁹⁰Y and ¹⁸⁸Re are the best candidates for solid tumour treatment when only one radionuclide is coupled to one carrier. Furthermore, regardless of the radionuclide properties, high values of TCP can be reached without toxicity if the number of radionuclides per nanoobject increases.

Bronchoscopy-Guided Cooled Radiofrequency Ablation as a Novel Intervention Therapy for Peripheral Lung Cancer

BACKGROUND

Our previous animal and preliminary human studies indicated that bronchoscopy-guided cooled radiofrequency ablation (RFA) for the lung is a safe and feasible procedure without major complications.

OBJECTIVES

The present study was performed to evaluate the safety, effectiveness and feasibility of computed tomography (CT)-guided bronchoscopy cooled RFA in patients with medically inoperable non-small-cell lung cancer (NSCLC).

METHODS

Patients with pathologically diagnosed NSCLC, who had no lymph node involvement or distant metastases (T1-2aN0M0) but were not surgical candidates because of comorbidities (e.g., synchronous multiple nodules, advanced age, cardiovascular disease, poor pulmonary function, etc.) were enrolled in the present study. The diagnosis and location between the nearest bronchus and target tumor were made by CT-guided bronchoscopy before the treatment. A total of 28 bronchoscopy-guided cooled RFA procedures were performed in 20 patients. After treatment, serial CT imaging was performed as follow-up.

RESULTS

Eleven lesions showed significant reductions in tumor size and 8 lesions showed stability, resulting in a local control rate of 82.6%. The median progression-free survival was 35 months (95% confidence interval: 22-45 months), and the 5-year overall survival was 61.5% (95% confidence interval: 36-87%). Three patients developed an acute ablation-related reaction (fever, chest pain) and required hospitalization but improved with conservative treatment. There were no other adverse events in the present study.

CONCLUSIONS

CT-guided bronchoscopy cooled RFA is applicable for only highly selected subjects; however, our trial may be an alternative strategy, especially for disease local control in medically inoperable patients with stage I NSCLC.

Radiation-induced rib fracture after stereotactic body radiotherapy with a total dose of 54-56 Gy given in 9-7 fractions for patients with peripheral lung tumor: impact of maximum dose and fraction size

BACKGROUND

Radiation-induced rib fracture after stereotactic body radiotherapy (SBRT) for lung cancer has been recently reported. However, incidence of radiation-induced rib fracture after SBRT using moderate fraction sizes with a long-term follow-up time are not clarified. We examined incidence and risk factors of radiation-induced rib fracture after SBRT using moderate fraction sizes for the patients with peripherally located lung tumor.

METHODS

During 2003-2008, 41 patients with 42 lung tumors were treated with SBRT to 54-56 Gy in 9-7 fractions. The endpoint in the study was radiation-induced rib fracture detected by CT scan after the treatment. All ribs where the irradiated doses were more than 80% of prescribed dose were selected and contoured to build the dose-volume histograms (DVHs). Comparisons of the several factors obtained from the DVHs and the probabilities of rib fracture calculated by Kaplan-Meier method were performed in the study.

RESULTS

Median follow-up time was 68 months. Among 75 contoured ribs, 23 rib fractures were observed in 34% of the patients during 16-48 months after SBRT, however, no patients complained of chest wall pain. The 4-year probabilities of rib fracture for maximum dose of ribs (Dmax) more than and less than 54 Gy were 47.7% and 12.9% (p = 0.0184), and for fraction size of 6, 7 and 8 Gy were 19.5%, 31.2% and 55.7% (p = 0.0458), respectively. Other factors, such as D2cc, mean dose of ribs, V10-55, age, sex, and planning target volume were not significantly different.

CONCLUSIONS

The doses and fractionations used in this study resulted in no clinically significant rib fractures for this population, but that higher Dmax and dose per fraction treatments resulted in an increase in asymptomatic grade 1 rib fractures.

SBRT in operable early stage lung cancer patients

Since decades the gold standard for treatment of early stage non-small cell lung cancer (NSCLC) is surgical lobectomy plus mediastinal lymph node dissection. Patients in worse health status are treated with sublobar resection or radiation treatment. With development of stereotactic-body-radiotherapy (SBRT), outcome of patients treated with radiation was substantially improved. Comparison of SBRT and surgical techniques is difficult due to the lack of randomized trials. However, all available evidence in form of case control studies of population based studies show equivalence between sublobar resection and SBRT indicating that SBRT-when performed by a trained and experienced team-should be offered to all high-risk surgical patients. For patients not willing to take the risk of lobectomy and therefore refusing surgery, SBRT is an excellent treatment option.