Stereotactic body radiotherapy for medically inoperable patients with stage I non-small cell lung cancer - a first report of toxicity related to COPD/CVD in a non-randomized prospective phase II study

Treatment planning and delivery practice of lung SBRT: Results of the 2022 ESTRO physics survey

BACKGROUND AND PURPOSE

The use of Stereotactic Body Radiation Therapy (SBRT) in lung cancer is increasing. However, there is no consensus on the most appropriate treatment planning and delivery practice for lung SBRT. To gauge the range of practice, quantify its variability and identify where consensus might be achieved, ESTRO surveyed the medical physics community.

MATERIALS AND METHODS

An online survey was distributed to ESTRO's physicist membership in 2022, covering experience, dose and fractionation, target delineation, dose calculation and planning practice, imaging protocols, and quality assurance.

RESULTS

Two-hundred and forty-four unique answers were collected after data cleaning. Most respondents were from Europe the majority of which had more than 5 years' experience in SBRT. The large majority of respondents deliver lung SBRT with the VMAT technique on C-arm Linear Accelerators (Linacs) employing daily pre-treatment CBCT imaging. A broad spectrum of fractionation schemes were reported, alongside an equally wide range of dose prescription protocols. A clear preference was noted for prescribing to 95% or greater of the PTV. Several issues emerged regarding the dose calculation algorithm: 22% did not state it while 24% neglected to specify the conditions under which the dose was calculated. Contouring was usually performed on Maximum or Average Intensity Projection images while dose was mainly computed on the latter. No clear indications emerged for plan homogeneity, complexity, and conformity assessment. Approximately 40% of the responders participated in inter-centre credentialing of SBRT in the last five years. Substantial differences emerged between high and low experience centres, with the latter employing less accurate algorithms and older equipment.

CONCLUSION

The survey revealed an evident heterogeneity in numerous aspects of the clinical implementation of lung SBRT treatments. International guidelines and codes of practice might promote harmonisation.

Stereotactic ablative radiotherapy (SABR) for patients with lung tumor and severe pulmonary function impairment

PURPOSE

To evaluate clinical outcomes after SABR in a cohort of early-stage non-small cell lung cancer (NSCLC) or pulmonary metastases in chronic obstructive pulmonary disease (COPD) patients with forced expiratory volume in the first second predicted (FEV1) ≤ 50%.

METHODS

Retrospective single-center study was performed to analyze clinical outcomes and toxicities in COPD patients with severe lung dysfunction treated with SABR from 1st June 2015 to 31st October 2022.

RESULTS

Thirty four patients (forty locations) were enrolled for analysis. Median follow-up was 2.9 years. Median age was 73.5 years (range, 65.6-80.1). FEV1 was 38% (range, 28.2-50.0) prior to radiotherapy. Median overall survival (OS) was 41.1 months (95% CI 38.9-not reached). OS rates at 2-, 3-, and 5- years were 79%, 71%, and 36%, respectively. Cancer-specific survival rates at 2-, 3-, and 5- years were 96%, 96%, and 68%, respectively. Local control rates at 2-, 3-, and 5- years were 88%, 83%, and 83%, respectively. No grade 4 or 5 toxicity was observed. The most common acute toxicity was pneumonitis (38.2%), of which only 1 patient (2.9%) reported grade 3 acute toxicity.

CONCLUSIONS

Lung SABR in patients with poor pulmonary function may be effective with acceptable toxicity.

Survival analysis after stereotactic ablative radiotherapy for early stage non-small cell lung cancer: a single-institution cohort study

BACKGROUND

Stereotactic ablative radiotherapy (SABR) is the standard treatment for medically inoperable early-stage non-small cell lung cancer (ES-NSCLC), but which patients benefit from stereotactic radiotherapy is unclear. The aim of this study was to analyze prognostic factors for early mortality.

METHODS

From August 2010 to 2022, 617 patients with medically inoperable, peripheral or central ES-NSCLC were treated with SABR at our institution. We retrospectively evaluated the data from 172 consecutive patients treated from 2018 to 2020 to analyze the prognostic factors associated with overall survival (OS). The biological effective dose was > 100 Gy10 in all patients, and 60 Gy was applied in 3-5 fractions for a gross tumor volume (GTV) + 3 mm margin when the tumor diameter was < 1 cm; 30-33 Gy was delivered in one fraction. Real-time tumor tracking or an internal target volume approach was applied in 96% and 4% of cases, respectively. In uni- and multivariate analysis, a Cox model was used for the following variables: ventilation parameter FEV1, histology, age, T stage, central vs. peripheral site, gender, pretreatment PET, biologically effective dose (BED), and age-adjusted Charlson comorbidity index (AACCI).

RESULTS

The median OS was 35.3 months. In univariate analysis, no correlation was found between OS and ventilation parameters, histology, PET, or centrality. Tumor diameter, biological effective dose, gender, and AACCI met the criteria for inclusion in the multivariate analysis. The multivariate model showed that males (HR 1.51, 95% CI 1.01-2.28; p = 0.05) and AACCI > 5 (HR 1.56, 95% CI 1.06-2.31; p = 0.026) were significant negative prognostic factors of OS. However, the analysis of OS showed that the significant effect of AACCI > 5 was achieved only after 3 years (3-year OS 37% vs. 56%, p = 0.021), whereas the OS in one year was similar (1-year OS 83% vs. 86%, p = 0.58).

CONCLUSION

SABR of ES-NSCLC with precise image guidance is feasible for all medically inoperable patients with reasonable performance status. Early deaths were rare in our real-life cohort, and OS is clearly higher than would have been expected after best supportive care.

Stereotactic radiosurgery in India: A nationwide survey of technology and quality assurance practices

PURPOSE

India is rapidly adopting advanced treatments like Stereotactic Radiosurgery (SRS). However, there is a paucity of data on SRS practice. The aim of study is to assess the current status of technology and practices of machine quality assurance (QA) and patient specific quality assurance for SRS in India.

MATERIALS AND METHODS

A survey questionnaire was designed using Google Forms and sent to chief/senior medical physicists across 220 radiotherapy centers in India on July 15, 2022. It contained questions on infrastructure availability, treatment planning, and QA.

RESULTS

SRS was found to be extensively used for the treatment of brain metastases (99.3%), followed by meningioma (50.3%), acoustic neuroma (45.5%), and pituitary tumours (33.1%). The most commonly used photon energy and treatment technique were 6MV FFF and VMAT, respectively. A prescription isodose line ranging from 70% to 100% was selected by linac users. Most linac institutes verify pretreatment doses. There was a lack of uniformity in the analysis metrics such as Low Dose Threshold, Dose Difference, and Distance to Agreement. A survey revealed that the variety of SRS QA programs being followed at Indian radiotherapy centers.

CONCLUSION

This is the first study to report the physics practice of SRS in India. The survey shows a need to carry out a postal dose audit for small static photon fields in India.

Optimizing lung cancer radiation therapy: A systematic review of multifactorial risk assessment for radiation-induced lung toxicity

BACKGROUND

Radiation therapy (RT) is essential in treating advanced lung cancer, but may lead to radiation pneumonitis (RP). This systematic review investigates the use of pulmonary function tests (PFT) and other parameters to predict and mitigate RP, thereby improving RT planning.

METHODS

A systematic review sifted through PubMed and on BioMed Central, targeting articles from September 2005 to December 2022 containing the keywords: Lung Cancer, Radiotherapy, and pulmonary function test.

RESULTS

From 1153 articles, 80 were included. RP was assessed using CTCAEv.4 in 30 % of these. Six studies evaluated post-RT quality of life in lung cancer patients, reporting no decline. Patients with RP and chronic obstructive pulmonary disease (COPD) generally exhibited poorer overall survival. Notably, forced expiratory volume in one second (FEV1) and diffusing capacity of the lung for carbon monoxide (DLCO) declined 24 months post-RT, while forced vital capacity (FVC) stayed stable. In the majority of studies, age over 60, tumors located in the lower part of the lung, and low FEV1 before RT were associated with a higher risk of RP. Dosimetric factors (V5, V20, MLD) and metabolic imaging emerged as significant predictors of RP risk. A clinical checklist blending patient and tumor characteristics, PFT results, and dosimetric criteria was proposed for assessing RP risk before RT.

CONCLUSION

The review reveals the multifactorial nature of RP development following RT in lung cancer. This approach should guide individualized management and calls for a prospective study to validate these findings and enhance RP prevention strategies.

Accelerated Hypofractionated Radiotherapy for Centrally Located Lung Tumours Not Suitable for Stereotactic Body Radiotherapy or Chemoradiotherapy

AIMS

Accelerated hypofractionated radiotherapy is used at our institution for non-small cell lung cancer (NSCLC) patients not eligible for stereotactic body radiotherapy or chemoradiotherapy. The purpose of this study was to report clinical outcomes of delivering 60 Gy in 15 fractions for these patients.

MATERIALS AND METHODS

All NSCLC patients who received 60 Gy in 15 fractions were reviewed. Outcomes of interest were local failure, regional failure, distant progression, overall survival and treatment-associated toxicities.

RESULTS

In total, 111 patients were included. The median age was 78.8 years and most tumours were adenocarcinoma (n = 55, 49.6%). Sixty-five patients (58.6%) were N0. The cumulative incidence of local failure at 12 and 24 months in the N0 cohort was 5.2% and 14.2%, respectively, compared with 11.5% and 14.8% for N+ patients. Tumour size >35 mm predicted for local failure (hazard ratio 2.706, 95% confidence interval 1.002-7.307, P = 0.0494). Distant progression at 12 and 24 months in N0 patients was 13.7% and 24.3% compared with 24.6% and 33.5% in N+ patients. In N0 patients, larger tumour size was associated with increased risk of distant progression. The median overall survival was 38.1 months in N0 patients versus 31.7 months in N+ patients. The most common toxicity was radiation pneumonitis (n = 6, 6.4%). The incidence of any grade 3 toxicity was 10.3% at ≥1 year. There were no deaths or hospitalisations attributed to treatment.

CONCLUSIONS

Accelerated hypofractionated radiotherapy is well tolerated and resulted in favourable clinical outcomes in various stages of NSCLC patients.

A guide for managing patients with stage I NSCLC: deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 4: systematic review of evidence involving SBRT and ablation

Background

Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.

Methods

A PubMed systematic review from 2000-2021 of outcomes after SBRT or thermal ablation vs. resection is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons with at least some adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.

Results

Short-term outcomes are meaningfully better after SBRT than resection. SBRT doesn't affect quality-of-life (QOL), on average pulmonary function is not altered, but a minority of patients may experience gradual late toxicity. Adjusted non-randomized comparisons demonstrate a clinically relevant detriment in long-term outcomes after SBRT vs. surgery. The short-term benefits of SBRT over surgery are accentuated with increasing age and compromised patients, but the long-term detriment remains. Ablation is associated with a higher rate of complications than SBRT, but there is little intermediate-term impact on quality-of-life or pulmonary function tests. Adjusted comparisons show a meaningful detriment in long-term outcomes after ablation vs. surgery; there is less difference between ablation and SBRT.

Conclusions

A systematic, comprehensive summary of evidence regarding Stereotactic Body Radiotherapy or thermal ablation vs. resection with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation for a framework for individualized decision-making.

CT Appearance Pattern After Stereotactic Body Radiation Therapy Predicts Outcomes in Early-Stage Non-Small-Cell Lung Cancer

Backgrounds

Computed tomography (CT) appearance pattern after lung tumor stereotactic body radiation therapy(SBRT) might predicts survival. This study aimed to investigate the correlation between CT appearance pattern after SBRT and outcomes in patients with early-stage non-small-cell lung cancer (NSCLC).

Methods

Clinical data of inoperable patients with early-stage NSCLC undergoing SBRT were retrospectively analyzed from 2012 to 2015 at the Zhejiang Cancer Hospital. The relationship between CT appearance pattern after SBRT and patient’s survival was analyzed.

Results

The data from 173 patients with early-stage lung cancer treated with SBRT were analyzed. One month after SBRT, diffuse consolidation was seen in 17 patients, patchy consolidation in 28 patients, diffuse ground-glass opacity (GGO) in 10 patients, and patchy GGO in 22 patients. The survival time was significantly longer in the “no evidence of increased density” group compared with the “consolidation or GGO” group [2-year overall survival (OS) rate, 96.1% vs 89.3%; hazard ratio (HR), 0.36; 95% confidence interval (CI), 0.16–0.85; P = 0.015]. A similar trend was found in the progression-free survival (PFS) analysis (2-year PFS rate, 91.3% vs 85.0%; HR, 0.35; 95% CI, 0.13–0.95; P = 0.015) and distant metastasis free survival(DMFS) (2-year DMFS rate, 93.3% vs 87.1%; HR, 0.41; 95% CI, 0.20–0.86; P = 0.031). However, no significant difference was found in recurrence-free survival between the two groups (P = 0.212).

Conclusions

One month after SBRT, the radiological change “no evidence of increased density” was prevalent. The OS, PFS, and DMFS were significantly longer in the “no evidence of increased density” group compared with the “consolidation or GGO” group. Further studies are needed to validate these findings.

Lung Function After Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer, Changes and Predictive Markers

Introduction

The present study explores changes in pulmonary function, symptoms and radiological signs of pneumonitis after curatively intended stereotactic body radiation therapy (SBRT).

Methods

All inoperable, early-stage non-small cell lung cancer patients treated with stereotactic body radiation therapy (SBRT) from 2014-2017 were included in this single-centre study. They were followed regularly for 12 months after treatment. The patients were classified into three groups based on radiology and symptomatology: no radiation pneumonitis, asymptomatic and symptomatic radiation pneumonitis.

Results

Forty-four patients with stage IA-IIB disease were treated with 45–56 Gy in 3–8 fractions. The median age was 75 years, 43% of the patients were female; 60% of the patients had a COPD in GOLD grade of 2-4, and 95.5% were active or former smokers. Symptomatic radiation pneumonitis occurred in 18% of the patients and asymptomatic pneumonitis as defined by radiology, in 39%. The mean of forced expiratory volume in 1 second (FEV1) and diffusion capacity for carbon monoxide (DLCO) decreases for all patients during the first years were higher than one would expect from physiologic ageing. FEV1 and DLCO in percent decrease 7-8% at 1-1.5 months in the symptomatic radiation pneumonitis group. CT scan findings consistent with radiation pneumonitis occurred after a median of 2.9 months in the symptomatic and 5.4 months in the asymptomatic radiation pneumonitis groups. In the group with symptomatic radiation pneumonitis, symptoms, as measured by the Clinical COPD questionnaire score, significantly increased at 3 and 6 months. Significant higher maximum doses to the critical lung volumes DC1000cm³ (1000 cm³ of lung receiving a given dose or less) and DC 1500cm³ (1500 cm³ of lung receiving a given dose or less) were observed in patients who developed radiation pneumonitis.

Conclusion

Early decrease in measured FEV1 and DLCO occurred before imaging changes and symptoms and might indicate the development of symptomatic radiation pneumonitis. The dose to critical lung volumes of DC1000 cm³ and DC1500 cm³ may predict the risk for the development of symptomatic radiation pneumonitis.

Outcomes of curative-intent radiotherapy in non-small cell lung cancer (NSCLC) patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD)

Outcomes of non-small cell lung cancer (NSCLC) patients with chronic obstructive pulmonary disease (COPD n = 587) and interstitial lung disease (ILD n = 34) treated with curative-intent radiotherapy were retrospectively investigated. Presence of ILD but not decreased forced expiratory volume in 1-second correlated with poor overall survival. Increased breathlessness and oxygen requirements after radiotherapy were observed in severe/very severe COPD and ILD.

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.

Stereotactic body radiation therapy using CyberKnife for T1N0M0 lung cancer patients with severe pulmonary dysfunction

We retrospectively investigated the efficacy and safety of stereotactic body radiotherapy (SBRT) for T1N0M0 lung cancer using CyberKnife (CK) among 13 patients with severe pulmonary dysfunction which was defined as forced expiratory volume in 1 s (FEV1.0) of <1 L. The prescribed dose was 54 Gy in 3 fractions but adjusted for some patients if their tumors were in close proximity to the organs at risk (54 Gy/3 fractions: n = 11; 50 Gy/5 fractions: n = 1; 60 Gy/8 fractions: n = 1). During follow up (median follow-up: 27 months), we evaluated local control, overall survival and toxicity, using diagnostic imaging and laboratory tests. The patients' median FEV1.0 was 0.84 L. Of the 13 patients, 3 were diagnosed as having lung cancer histologically and 10 diagnosed clinically. Their 2-year rates for overall survival and local control were 89 and 100%, respectively. So far, we have seen no adverse effects of grade 2 or higher. We concluded that CK-SBRT is effective and well tolerated for T1N0M0 lung cancer, even in patients with severe pulmonary dysfunction, but should be further evaluated with a larger cohort and longer follow-up periods.

Bronchoscopic treatments for early-stage peripheral lung cancer: Are we ready for prime time?

Lung cancer is the leading cause of cancer-related death worldwide and surgical lobectomy remains the preferred therapy for patients with early-stage NSCLC. Medical comorbidities and advanced age preclude resection in many patients and minimally invasive ablative therapies are needed for treatment. Stereotactic ablative radiation is established as an effective modality in this patient group, although may be contraindicated in some patients with prior radiation exposure, comorbidities or centrally positioned tumours. Percutaneous ablative methods are available, although are frequently associated with significant complications. Numerous endoscopic ablative techniques are under evaluation. With a more favourable safety profile and the ability to provide diagnosis and staging information potentially within a single procedure, there is a strong rationale for development of bronchoscopic ablative modalities. In the following article, the authors aim to explore the role bronchoscopic ablation may play in treatment of peripheral lung tumours, and to describe a pathway to establishing these modalities as part of routine care. The current status of several bronchoscopic ablative options is discussed in detail.

Oncologic Outcomes of Surgery Versus SBRT for Non-Small-Cell Lung Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

The optimal treatment of stage I non-small-cell lung carcinoma is subject to debate. The aim of this study was to compare overall survival and oncologic outcomes of lobar resection (LR), sublobar resection (SR), and stereotactic body radiotherapy (SBRT).

METHODS

A systematic review and meta-analysis of oncologic outcomes of propensity matched comparative and noncomparative cohort studies was performed. Outcomes of interest were overall survival and disease-free survival. The inverse variance method and the random-effects method for meta-analysis were utilized to assess the pooled estimates.

RESULTS

A total of 100 studies with patients treated for clinical stage I non-small-cell lung carcinoma were included. Long-term overall and disease-free survival after LR was superior over SBRT in all comparisons, and for most comparisons, SR was superior to SBRT. Noncomparative studies showed superior long-term overall and disease-free survival for both LR and SR over SBRT. Although the papers were heterogeneous and of low quality, results remained essentially the same throughout a large number of stratifications and sensitivity analyses.

CONCLUSION

Results of this systematic review and meta-analysis showed that LR has superior outcomes compared to SBRT for cI non-small-cell lung carcinoma. New trials are underway evaluating long-term results of SBRT in potentially operable patients.

Development and external validation of a nomogram to predict overall survival following stereotactic body radiotherapy for early-stage lung cancer

BACKGROUND

Prognostication tools for early-stage non-small cell lung cancer (NSCLC) patients treated with stereotactic body radiotherapy (SBRT) are currently lacking. The purpose of this study was to develop and externally validate a nomogram to predict overall survival in individual patients with peripheral early-stage disease.

METHODS

A total of 587 NSCLC patients treated with biologically effective dose > 100 Gy₁₀ were eligible. A Cox proportional hazards model was used to build a nomogram to predict 6-month, 1-year, 3-year and 5-year overall survival. Internal validation was performed using bootstrap sampling. External validation was performed in a separate cohort of 124 NSCLC patients with central tumors treated with SBRT. Discriminatory ability was measured by the concordance index (C-index) while predictive accuracy was assessed with calibration slope and plots.

RESULTS

The resulting nomogram was based on six prognostic factors: age, sex, Karnofsky Performance Status, operability, Charlson Comorbidity Index, and tumor diameter. The slope of the calibration curve for nomogram-predicted versus Kaplan-Meier-estimated overall survival was 0.77. The C-index of the nomogram (corrected for optimism) was moderate at 0.64. In the external validation cohort, the model yielded a C-index of 0.62.

CONCLUSIONS

We established and validated a nomogram which can provide individual survival predictions for patients with early stage lung cancer treated with SBRT. The nomogram may assist patients and clinicians with treatment decision-making.

[Prognosis factors after lung stereotactic body radiotherapy for non-small cell lung carcinoma]

Lung cancer is the fourth most common cancer in France with a prevalence of 30,000 new cases per year. Lobectomy surgery with dissection is the gold standard treatment for T1-T2 localized non-small cell lung carcinoma. A segmentectomy may be proposed to operable patients but fragile from a respiratory point of view. For inoperable patients or patients with unsatisfactory pulmonary function tests, local treatment with stereotactic radiotherapy may be proposed to achieve local control rates ranging from 85 to 95% at 3-5 years. Several studies have examined prognostic factors after stereotaxic pulmonary radiotherapy. We conducted a general review of the literature to identify factors affecting local control.

Radiation-induced brachial plexus toxicity after SBRT of apically located lung lesions

Purpose: To evaluate the rate and dose response of brachial plexus toxicity post stereotactic body radiation therapy (SBRT) of apically situated lung lesions. Material/methods: We retrospectively identified all patients with apically located tumors, defined by the epicenter of the tumor being located superiorly to the aortic arch, and treated with SBRT between 2008 and 2013. Patients with a shorter follow-up than 6 months were excluded. Primary aim was to evaluate radiation-induced brachial plexopathy (RIBP). Dose to the plexus was assessed by a retrospective delineation of the brachial plexus on the CT used for treatment planning. Then, D_max, D_0.1cc, D_1cc and D_3.0cc of the brachial plexus were collected from the dose-volume histograms (DVH) and recalculated to the biologically effective dose (BED) using α/β = 3 Gy. A normal tissue complication probability (NTCP) model, based on four different dose-volume parameters (BED_3,max, BED_3,0.1cc, BED_3,1.0cc, BED_3,3.0cc) was fitted to the data. Results: Fifty-two patients with 56 apically located tumors were identified. Median prescription dose per fraction was 15 Gy (range 6-17) and median number of fractions was 3 (3-10). With a median follow-up of 30 months (6.1-72) seven patients experienced maximum grade 2 (scored 3 times) or 3 (scored 4 times) RIBP after a median of 8.7 months (range 4.0-31). Three patients had combined symptoms with pain, sensory and motor affection and four patients had isolated pain. Median BED_3,max for the patients experiencing RIBP was 381 Gy (range 30-524) versus BED_3,max of 34 Gy (range 0.10-483) for the patients without RIBP. The NTCP models showed a very high predictive ability (area under the receiver operating characteristic curve (AUC) 0.80-0.88). Conclusion: SBRT of apically located lung lesions may cause severe neurological symptoms; for a three-fraction treatment, we suggest that the maximum dose to the plexus should be kept ≤30 Gy (130 Gy BED₃).

Choice of immobilization of stereotactic body radiotherapy in lung tumor patient by BMI

BACKGROUND

An accurate, reproducible, and comfortable immobilization device is essential for stereotactic radiotherapy (SBRT) in patients with lung cancer. This study compared thermoplastic masks (TMP) and vacuum cushion (VCS) system to assess the differences in interfraction and intrafraction setup accuracy and the impact of body mass index (BMI) with respect to the immobilization choice.

METHODS

This retrospective study was conducted on patients treated with lung SBRT between 2012 and 2015 at the Zhejiang cancer hospital. The treatment setup accuracy was analyzed in 121 patients. A total of 687 cone beam computed tomography (CBCT) scans before treatment and 126 scans after treatment were recorded to determine the uncertainties, and plan target volume margins. Data were further stratified and analyzed by immobilization methods and patients' BMI. The t-test (Welch) was used to assess the differences between the two immobilization systems when stratified by the patients' BMI.

RESULTS

For patients with BMI ≥ 24, the mean displacements for the TMP and VCS systems were 1.4 ± 1.2 vs. 2.4 ± 2.0 mm at medial-lateral (ML) direction (p < 0.001); 2.0 ± 1.9 vs. 2.0 ± 1.9 mm at cranial-caudal (CC) direction (p = 0.917); and 2.4 ± 1.4 vs. 2.6 ± 2.1 mm at anterior-posterior (AP) direction, (p = 0.546). The rate of acceptable errors increased dramatically when immobilized by TMP. In the case of patients with BMI < 24, the mean displacements for the TMP and VCS systems were 1.8 ± 1.4 vs. 2.1 ± 1.8 mm at ML direction (p = 0.098); 2.9 ± 2.3 vs. 2.2 ± 2.2 mm at CC direction (p = 0.001); and 1.8 ± 1.8 vs. 2.3 ± 2.0 mm at CC direction, (p = 0.006). The proportion of acceptable errors increased after immobilization by VCS. No difference was detected in the intrafraction setup error by different immobilization methods.

CONCLUSIONS

The immobilization choice of SBRT for lung tumors depends on the BMI of the patients. For patients with BMI ≥ 24, TMP offers a better reproducibility with significantly less interfractional setup displacement than VCS, resulting in fewer CBCT scans. However, VCS may be preferred over TMP for the patients with BMI < 24. Therefore, an optimal immobilization system needs to be considered in different BMI groups for lung SBRT.

Stereotactic body radiotherapy in patients with chronic obstructive pulmonary disease and interstitial pneumonia: a review

Stereotactic body radiation therapy (SBRT) can yield excellent local tumor control, as well as survival benefit comparable to that of surgery for early-stage lung cancer. However, in terms of toxicity, SBRT might lead to fatal radiation pneumonitis. Lung diseases, such as chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD), are major risk factors for lung cancer. However, these patients are typically not candidates for the gold-standard treatment option, lobectomy, because of the perioperative risks. In addition, patients with poor respiratory function can be excluded in prospective clinical trials. Thus, SBRT for patients with pulmonary diseases is still challenging, but there appears to be a clinical role for this modality as an alternative treatment. However, there are few well-documented review articles on SBRT for patients with pulmonary diseases. Therefore, we aimed to review SBRT in the context of important patient-related factors, including COPD and ILD. SBRT is an acceptable alternative treatment option for patients with lung cancer who also have COPD with an equivalent risk of radiation pneumonitis to normal lung. However, latent ILD should be detected prior to treatment. The indication for SBRT should be decided by carefully considering the risks and benefit for patients with ILD.

Prediction of early mortality following stereotactic body radiotherapy for peripheral early-stage lung cancer

BACKGROUND/PURPOSE

To investigate prognostic factors for death within 6 months of stereotactic body radiotherapy (SBRT) for patients with peripheral early-stage non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

This analysis included 586 NSCLC patients with peripheral tumors treated with SBRT. Potential patient and tumor prognostic factors, including the Charlson Comorbidity Index (CCI) and Cumulative Illness Rating Scale (CIRS), were analyzed by logistic regression analysis for association with early mortality (death <6 months after SBRT). Additionally, CCI and CIRS were compared with respect to their predictive ability for early mortality by comparing multivariate models with each comorbidity index, and assessing their respective discriminatory abilities (C-index).

RESULTS

A total of 36 patients (6.1%) died within 6 months of the start of SBRT. With a median follow-up of 25 months, 3-year overall survival was 54%. CIRS and tumor diameter were significant predictors of early mortality on multivariate analysis (p = .001). Patients with a CIRS score of 8 or higher and a tumor diameter over 3 cm had a 6-month survival of 70% versus 97% for those lacking these two features (p < .001). CCI was not predictive for early mortality on univariate nor multivariate analysis; the model containing CCI had a C-index of 0.65 versus 0.70 for the model containing CIRS.

CONCLUSION

CIRS and tumor diameter predict for early-mortality in peripheral early-stage NSCLC treated with SBRT. CIRS may be a more useful comorbidity index than CCI in this population when assessing short-term life expectancy.

Treatment-Related Adverse Effects in Lung Cancer Patients after Stereotactic Ablative Radiation Therapy

Introduction

Lung cancer is a disease which, despite the advancements in treatment, still has a very poor 5-year survival rate. Stereotactic ablative radiation therapy (SABR) is a highly advanced, sophisticated, and safe treatment which allows patients with early stage lung cancer to be treated effectively without invasive procedures and with excellent clinical outcomes. Avoiding surgery minimises morbidity and recovery time, bettering patients' quality of life. Furthermore, SABR allows patients unsuitable for surgery to still undergo curative treatment.

Methods

We aimed to review SABR-related normal tissue toxicities reported in the literature. While many studies assess safety, clinical efficacy, and disease control of SABR for lung cancer, the number of comprehensive reviews that analyse SABR-related side-effects is scarce. This integrative review summarises the toxicities reported in literature based on published clinical trials and tumour location (central or peripheral tumours) for available SABR techniques. Given that the majority of the clinical studies did not report on the statistical significance (e.g., p-values and confidence intervals) of the toxicities experienced by patients, statistical analyses cannot be performed. As a result, adverse events are compiled from clinical reports; however, due to various techniques and nonstandard toxicity reports, no meta-analysis is possible at the current stage of reported data.

Results

When comparing lobectomy and SABR in phase III trials, surgery resulted in increased procedure-related morbidity. In phase II trials, very few studies showed high grade toxicities/fatalities as a result of SABR for lung cancer. Gross target volume size was a significant predictor of toxicity. An ipsilateral mean lung dose larger than 9 Gy was significantly associated with radiation pneumonitis.

Conclusions

Based on the studies reviewed SABR is a safe treatment technique for lung cancer; however, further well-designed phase III randomised clinical trials are required to produce timely conclusive results and to enable their comparison and statistical analysis.

Do SABR-related toxicities for lung cancer depend on treatment delivery?

Stereotactic ablative radiation therapy for lung cancer is an advanced technique where tumours are ablated with hypofractionated radiation doses, with a high degree of accuracy. The aim of this paper is to review the available literature and to discuss the SABR-induced toxicities for lung malignancies as a function of radiation delivery technique. A Medline search was conducted to identify the appropriate literature to fulfil the aim of this review and data from all applicable papers were collated and analysed. The most common techniques of SABR delivery employ linear accelerators, CyberKnife robotic radiosurgery system, TomoTherapy and the Novalis beam surgery system. Linear accelerator-based treatments give rise to a variety of toxicities that are strongly dependent on both patient-related factors and planning/dosimetry-related factors. The limited number of studies using CyberKnife reported low grade toxicities. Grade three toxicities mainly include fatigue and chest pain, usually in less than 10% of patients. All treatment techniques presented show efficiency in SABR delivery with various toxicities which, at this stage, cannot render one technique better than the other. For more conclusive results, well-designed phase three randomised clinical trials are required with better patient selection criteria, including dose and fractionation, treatment machine and technique, along with the consistent selection of a common toxicity grading criterion.

Implications for high-precision dose radiation therapy planning or limited surgical resection after percutaneous computed tomography-guided lung nodule biopsy using a tract sealant

Purpose

Precision radiation therapy such as stereotactic body radiation therapy and limited resection are being used more frequently to treat intrathoracic malignancies. Effective local control requires precise radiation target delineation or complete resection. Lung biopsy tracts (LBT) on computed tomography (CT) scans after the use of tract sealants can mimic malignant tract seeding (MTS) and it is unclear whether these LBTs should be included in the calculated tumor volume or resected. This study evaluates the incidence, appearance, evolution, and malignant seeding of LBTs.

Methods and materials

A total of 406 lung biopsies were performed in oncology patients using a tract sealant over 19 months. Of these patients, 326 had follow-up CT scans and were included in the study group. Four thoracic radiologists retrospectively analyzed the imaging, and a pathologist examined 10 resected LBTs.

Results

A total of 234 of 326 biopsies (72%, including primary lung cancer [n = 98]; metastases [n = 81]; benign [n = 50]; and nondiagnostic [n = 5]) showed an LBT on CT. LBTs were identified on imaging 0 to 3 months after biopsy. LBTs were typically straight or serpiginous with a thickness of 2 to 5 mm. Most LBTs were unchanged (92%) or decreased (6.3%) over time. An increase in LBT thickness/nodularity that was suspicious for MTS occurred in 4 of 234 biopsies (1.7%). MTS only occurred after biopsy of metastases from extrathoracic malignancies, and none occurred in patients with lung cancer.

Conclusions

LBTs are common on CT after lung biopsy using a tract sealant. MTS is uncommon and only occurred in patients with extrathoracic malignancies. No MTS was found in patients with primary lung cancer. Accordingly, potential alteration in planned therapy should be considered only in patients with LBTs and extrathoracic malignancies being considered for stereotactic body radiation therapy or wedge resection.

Lung Cancer: Posttreatment Imaging: Radiation Therapy and Imaging Findings

Over the last few decades, advances in radiation therapy technology have markedly improved radiation delivery. Advancements in treatment planning with the development of image-guided radiotherapy and techniques such as proton therapy, allow precise delivery of high doses of radiation conformed to the tumor. These advancements result in improved locoregional control while reducing radiation dose to surrounding normal tissue. The radiologic manifestations of these techniques can differ from radiation induced lung disease seen with traditional radiation therapy. Awareness of these radiologic manifestations and correlation with radiation treatment plans are important to differentiate expected radiation induced lung injury from recurrence, infection and drug toxicity.

Lung Cancer: Posttreatment Imaging: Radiation Therapy and Imaging Findings

In this review, we discuss the different radiation delivery techniques available to treat non-small cell lung cancer, typical radiologic manifestations of conventional radiotherapy, and different patterns of lung injury and temporal evolution of the newer radiotherapy techniques. More sophisticated techniques include intensity-modulated radiotherapy, stereotactic body radiotherapy, proton therapy, and respiration-correlated computed tomography or 4-dimensional computed tomography for radiotherapy planning. Knowledge of the radiation treatment plan and technique, the completion date of radiotherapy, and the temporal evolution of radiation-induced lung injury is important to identify expected manifestations of radiation-induced lung injury and differentiate them from tumor recurrence or infection.

Stereotactic body radiation therapy (SBRT) in the management of non-small-cell lung cancer: Clinical impact and patient perspectives

Stereotactic body radiation therapy (SBRT) has emerged as a new technology in radiotherapy delivery, allowing for potentially curative treatment in many patients previously felt not to be candidates for radical surgical resection of stage I non-small-cell lung cancer (NSCLC). Several studies have demonstrated very high local control rates using SBRT, and more recent data have suggested overall survival may approach that of surgery in operable patients. However, SBRT is not without unique toxicities, and the balance of toxicity, and effect on patient-reported quality of life need to be considered with respect to oncologic outcomes. We therefore aim to review SBRT in the context of important patient-related factors, including quality of life in several domains (and in comparison to other therapies such as conventional radiation, surgery, or no treatment). We will also describe scenarios in which SBRT may be reasonably offered (i.e. elderly patients and those with severe COPD), and where it may need to be approached with some caution due to increased risks of toxicity (i.e. tumor location, patients with interstitial lung disease). In total, we hope to characterize the physical, emotional, and functional consequences of SBRT, in relation to other management strategies, in order to aid the clinician in deciding whether SBRT is the optimal treatment choice for each patient with early stage NSCLC.

Imaging of Radiation Treatment of Lung Cancer

Radiation therapy is an important modality in the treatment of patients with lung cancer. Recent advances in delivering radiotherapy were designed to improve loco-regional tumor control by focusing higher doses on the tumor. More sophisticated techniques in treatment planning include 3-dimensional conformal radiation therapy, intensity-modulated radiotherapy, stereotactic body radiotherapy, and proton therapy. These methods may result in nontraditional patterns of radiation injury and various radiologic appearances that can be mistaken for recurrence, infection and other lung diseases. Knowledge of radiological manifestations, awareness of new radiation delivery techniques and correlation with radiation treatment plans are essential in order to correctly interpret imaging in these patients.

Lung segmentectomy: does it offer a real functional benefit over lobectomy?

Anatomical segmentectomy has been developed to offer better pulmonary function preservation than lobectomy, in stage IA lung cancer. Despite the retrospective nature of most of the studies and the lack of randomised studies, a substantial body of literature today allows us to evaluate to what extent lung function decreases after segmentectomy and whether segmentectomy offers a real functional benefit over lobectomy. From the available series, it emerges that the mean decrease in forced expiratory volume in 1 s (FEV1) is low, ranging from −9% to −24% of the initial value within 2 months and −3 to −13% 12 months after segmentectomy. This reduction in lung function is significantly lower than that induced by lobectomy, but saves only a few per cent of pre-operative FEV1. Moreover, the published results do not firmly establish the functional benefit of segmentectomy over lobectomy in patients with poor lung function. Some issues remain to be addressed, including whether video-assisted thoracic surgery (VATS) segmentectomy may preserve lung function better than VATS lobectomy in patients with poor lung function, especially within the early days after surgery, and whether this may translate to lowering the functional limit for surgery. Eventually, trials comparing stereotactic ablative body radiotherapy, radiofrequency ablation and segmentectomy functional consequences are warranted.

A Propensity-Matched Analysis of Outcomes of Patients with Clinical Stage I Non-Small Cell Lung Cancer Treated surgically or with stereotactic radiotherapy: A Meta-Analysis

OBJECTIVE

The aim of this study was to compare the efficacy between SBRT and surgery based on the Propensity-Matched Analysis.

METHODS

Publications on comparison SBRT and Surgery for early stage non- small cell lung cancer (NSCLC) from 2011 to 2017 were collected. Propensity score matching was used to achieve comparable treatment hazard ratios of the overall survival (OS), local control survival (LC), regional control survival (RC), loco-regional control survival (LRC), distant control survival (DC), disease-free survival (DFS), and progression-free survival (PFS) between SBRT and Surgery. The major outcomes measures were hazard ratios (HRs). Meta-analysis Revman 5.3 software was used to analyze the combined Pooled HRs using fixed- or random-effects models according to the heterogeneity.

RESULT

Eleven studies met our inclusion criteria. The LC, L-R C, DC, DFS and PFS rates of patients with early-stage lung cancer who were treated with SBRT are equal to surgical results. While, patients with surgery achieved superior OS compared with SBRT.

CONCLUSION

In this study we carried out a meta-analysis, which controls the acceptable level of the efficacy in the propensity score to match patients. The surgery had obvious OS advantages in this meta-analysis. However, these conclusions would be proven by further studies incorporating comorbidity data, and outcomes from randomized control study. The final decision for the optimal treatment of a patient with early-stage NSCLC can be substantiated by a personalized treatment model.

Assessment and management of radiotherapy induced toxicity in older patients

Radiotherapy is an attractive treatment option for older adults, especially where surgery and chemotherapy pose too great a risk. Radiotherapy toxicity may be divided into acute/early and late effects of treatment. The latter may have limited relevance to an older patient with competing causes of mortality due to significant comorbidity. Altered fractionation regimes have been employed in numerous sites, with no significant toxicity impact. These offer greater convenience in the elderly, especially those with limited social support or in active caregiving roles. As radiotherapy toxicity is site specific, it's important to assess baseline function via Comprehensive Geriatric Assessment (CGA), and any pre-existing comorbidities that may influence toxicity. With modern radiotherapy technology and capabilities, these are less of an issue and radiotherapy is a very suitable treatment option for the older adult. When evaluating the literature on toxicity in older patients, it's important to recognise that older studies do not represent modern day radiotherapy techniques and capabilities. Advanced technology may simultaneously deliver enhanced target coverage and reduced toxicity. More research is required related to the predictive power of CGA in linking radiotherapy toxicity to frailty. What little evidence exists shows that CGA has a role in treatment of older patients with radiotherapy and that, in general, radiotherapy appears to be well tolerated in older adults. The purpose of this review is to provide a broad overview of the mechanisms of normal tissue reactions to radiotherapy and how radiation induced toxicity may affect older patients.

Sinoatrial node toxicity after stereotactic ablative radiation therapy to lung tumors

PURPOSE

Stereotactic ablative radiation therapy (SABR) is an established treatment for selected lung tumors. Sinoatrial node (SAN) toxicity after thoracic SABR has not been reported in the literature. We sought to understand the risk of SAN toxicity owing to incidental dose to the SAN from SABR.

METHODS AND MATERIALS

We conducted a retrospective review of patients with early-stage lung cancer or limited pulmonary metastases who underwent thoracic SABR to a right-sided central lung tumor (within 2 cm of the mainstem bronchus or other mediastinal structures) between January 2008 and December 2014, analyzed a subset whose treatment imparted dose to the SAN exceeding 10% of the prescription dose, and examined patient and treatment dosimetric characteristics. Mean follow-up interval was 28 months. Time to toxicity was defined from start of SABR.

RESULTS

Of 47 patients with central tumors in the right lung treated with SABR reviewed, 13 met our study criteria. A contouring atlas of regional cardiac anatomy was created. One patient treated with SABR for non-small cell lung cancer at the right hilum developed symptomatic sick sinus syndrome, requiring pacemaker placement 6 months after treatment. Her acute presentation and short interval between SABR and onset of symptoms suggest that SAN toxicity was likely due to radiation-induced injury. Both her age and mean dose to her SAN were the third highest in our cohort. She remained free from cancer progression at 24 months' follow-up. Twelve additional patients who received significant dose to the SAN from SABR did not develop toxicity.

CONCLUSION

While uncommon, SAN toxicity from SABR to right-sided central thoracic tumors should be recognized and followed in future studies.

Surgical management of lung metastases

Management of pulmonary metastases has evolved considerably over the last few decades but is still controversial. The surgical management of lung metastases is outlined, discussing the preoperative management, indications for surgery, the surgical approach and outcomes according to the primary histology.

Predicting risk factors for radiation pneumonitis after stereotactic body radiation therapy for primary or metastatic lung tumours

OBJECTIVE

To investigate risk factors for radiation-induced pneumonitis (RP) after hypofractionated stereotactic body radiotherapy (SBRT) in patients with lung tumours.

METHODS

From May 2004 to January 2016, 66 patients with 71 primary or metastatic lung tumours were treated with SBRT; these 71 cases were retrospectively analyzed for RP. To explore the risk factors for RP, the following factors were investigated: age, sex, performance status, operability, number of treatments, respiratory gating, pulmonary emphysema, tumour location and subclinical interstitial lung disease (ILD). Irradiated underlying lung volumes of more than 5 Gy, 10 Gy, 20 Gy and 30 Gy (Lung V5, V10, V20 and V30), mean lung dose and volumes of gross tumour volume (in cubic centimetre) and planning target volume were calculated for possible risk factors of RP.

RESULTS

The median follow-up period was 32 months. RP of Grade 2 or more, according to the Common Terminology Criteria for Adverse Events v. 4.0, was detected in 6 (8.4%) of the 71 cases. Grade 5 RP was identified in two cases. Of the risk factors of RP, subclinical ILD was the only factor significantly associated with the occurrence of RP of Grade 2 or more (p < 0.001). Both cases with Grade 5 RP had ILD with a honeycombing image.

CONCLUSION

Subclinical ILD was the only significant factor for Grade 2-5 RP. In addition, the cases with honeycombing had a high potential for fatality related to severe RP. Patients with subclinical ILD should be carefully monitored for the occurrence of severe RP after SBRT. Advances in knowledge: Hypofractionated SBRT for primary or metastatic lung tumours provides a high local control rate and safe treatment.

Development of patient-specific phantoms for verification of stereotactic body radiation therapy planning in patients with metallic screw fixation

A new technique for manufacturing a patient-specific dosimetric phantom using three-dimensional printing (PSDP_3DP) was developed, and its geometrical and dosimetric accuracy was analyzed. External body contours and structures of the spine and metallic fixation screws (MFS) were delineated from CT images of a patient with MFS who underwent stereotactic body radiation therapy for spine metastasis. Contours were converted into a STereoLithography file format using in-house program. A hollow, four-section PSDP was designed and manufactured using three types of 3DP to allow filling with a muscle-equivalent liquid and insertion of dosimeters. To evaluate the geometrical accuracy of PSDP_3DP, CT images were obtained and compared with patient CT data for volume, mean density, and Dice similarity coefficient for contours. The dose distribution in the PSDP_3DP was calculated by applying the same beam parameters as for the patient, and the dosimetric characteristics of the PSDP_3DP were compared with the patient plan. The registered CT of the PSDP_3DP was well matched with that of the real patient CT in the axial, coronal, and sagittal planes. The physical accuracy and dosimetric characteristics of PSDP_3DP were comparable to those of a real patient. The ability to manufacture a PSDP representing an extreme patient condition was demonstrated.

[Current Status of Stereotactic Ablative Radiotherapy (SABR) for Early-stage Non-small Cell Lung Cancer]

目前比较立体定向消融放疗（stereotactic ablative radiotherapy, SABR）与手术治疗早期非小细胞肺癌（non-small cell lung cancer, NSCLC）的随机研究证据尚不多，高水平的循证医学证据更是缺乏。尽管STARS和ROSEL两项随机研究结果荟萃分析显示SABR较手术耐受性更好，生存不劣于手术，但是目前仍仅推荐拒绝手术或不可手术的早期NSCLC首选SABR，期待着正在进行的随机研究VALOR（Veterans Affairs Lung Cancer Surgery or Stereotactic Radiotherapy in the US）和SABRTooth（SABRTooth study in the United Kingdom）的结果。许多回顾性的研究和病例对照研究显示了SABR治疗的安全性和有效性（局部控制率达90%以上，5年生存率达70%），但是由于肿瘤分期定义、如何决定可否手术及手术患者采用手术方式（开胸或胸腔镜辅助）等不同，很难比较SABR和手术的优劣，尽管大部分结论是两种方法疗效相似，但难以成为循证医学证据，因此争论热点是哪一种方法更安全、创伤更小。本文将就以上争论热点进行述评。

Treatment of Peripheral Non-Small Cell Lung Carcinoma with Stereotactic Body Radiation Therapy

Stereotactic body radiation therapy (SBRT) is an effective and well-tolerated noninvasive treatment for medically inoperable patients with peripheral non-small cell lung carcinoma. The term "peripheral" refers to lesions that lie 2 cm or more from the mediastinum and proximal bronchial tree and was instituted based on results from a specific dose and fractionation schedule. Improvements in immobilization, respiratory motion management, and image guidance have allowed for SBRT's highly conformal and accurate delivery of large radiation doses per fraction. Results from prospective and retrospective studies suggest that lung SBRT has superior outcomes when compared with conventionally fractionated treatments and is comparable with surgical resection. Investigations into the optimal SBRT dosing regimen for peripheral lesions are ongoing, with recent trials suggesting comparable efficacy between single and multiple fraction schedules. Chest wall toxicity after peripheral treatment is common, but it usually resolves with conservative management. Pneumonitis is less often observed after treatment of peripheral lesions, and changes in pulmonary function tests are minimal. Studies in the frail and elderly suggest that neither baseline pulmonary function tests nor age should preclude treatment. Recent technical developments have reduced delivery time and resulted in more conformal treatments. This review is on behalf of the IASLC Advanced Radiation Technology Committee.

Lung stereotactic ablative radiotherapy (SABR): dosimetric considerations for chest wall toxicity

OBJECTIVE

To investigate chest wall pain in patients with peripheral early stage lung cancer treated with stereotactic ablative radiotherapy (SABR), and to identify factors predictive of Common Terminology Criteria of Adverse Events Grade 2 + chest wall pain.

METHODS

Patients who received 55 Gy in five fractions were included. A chest wall structure was retrospectively defined on planning scans, and chest wall dosimetry and tumour-related factors recorded. Logistic regression was performed to identify factors predictive of ≥Grade 2 chest wall pain.

RESULTS

182 patients and 187 tumours were included. There were 20 (10.9%) episodes of ≥Grade 2 chest wall pain. Multivariate logistic regression demonstrated that the maximum dose received by 1 cm(3) of chest wall (Dmax1 cm(3)) and tumour size were significant predictors of ≥Grade 2 chest wall pain [Dmax1 cm(3) odds ratio : 1.104, 95% confidence interval : 1.012-1.204, p = 0.025; tumour size (mm) odds ratio : 1.080, 95% confidence interval : 1.026-1.136, p = 0.003]. This model was an adequate fit to the data (Hosmer and Lemeshow test non-significant) and a fair discriminator for chest wall pain (area under receiver-operating characteristic curve: 0.74). Using the multivariate logistic regression model, parameters for Dmax1 cm(3) are provided, which predict <10% and <20% risks of ≥Grade 2 chest wall pain for different tumour sizes.

CONCLUSION

Grade 2+ chest wall pain is an uncommon side effect of lung SABR. Larger tumour size and increasing Dmax1 cm(3) are significant predictors of ≥Grade 2 chest wall pain. When planning lung SABR, it is prudent to try to avoid hot volumes in the chest wall, particularly for larger tumours.

ADVANCES IN KNOWLEDGE

This article demonstrates that Grade 2 or greater chest wall pain following lung SABR is more common when the tumour is larger in size and the Dmax1 cm(3) of the chest wall is higher. When planning lung SABR, the risk of chest wall pain may be reduced if maximum doses are minimized, particularly for larger tumours.

Phase II Trial of SBRT for Stage I NSCLC: Survival, Local Control, and Lung Function at 36 Months

OBJECTIVES

The long-term impact of stereotactic body radiotherapy (SBRT) on respiratory function in patients with inoperable non-small cell lung cancer (NSCLC) has not been well studied. The aim of this phase II trial was to assess local control, survival, and lung function at 36 months after treatment.

METHODS

From July 2008 to February 2012, 42 patients in whom inoperable NSCLC with peripheral lesions was diagnosed were consecutively enrolled. Lung function testing included measurement of forced expiratory vital capacity, forced expiratory volume in 1 second, and diffusing capacity for carbon monoxide. All lung function parameters were registered at baseline and evaluated prospectively after SBRT every 6 months for 2 years and annually thereafter.

RESULTS

Of the 42 initial patients, four were excluded. At 36 months after SBRT, 22 patients were still evaluable (12 deaths and four patients lost to follow-up). At 36 months, the rate of local control was 94%. At 1, 2, and 3 years, respectively, overall survival rates were 92%, 75%, and 66%. Median overall survival was 57 months. Grade (G) 3 acute toxicity was observed in four patients (10%). Chronic G1 toxicity was observed in all 38 cases (100%), with the most common type being pneumonitis (26 patients [68%]). The mean lung function parameters at baseline and at 36 months after treatment were as follows: forced expiratory vital capacity 83% versus 79%; forced expiratory volume in 1 second 62% versus 57%; and diffusing capacity for carbon monoxide 54% versus 54%. These changes were not significant.

CONCLUSIONS

In this trial, local control and survival rates after SBRT were very good. Treatment with SBRT had no significant impact on lung function at 36 months. These findings provide further support for the use of SBRT as a radical treatment for NSCLC. Lung toxicity is minimal, even in patients with poor pulmonary function before treatment.

The Fate of Residual Tumor Masses That Persist After Stereotactic Body Radiotherapy for Solitary Lung Nodules: Will They Recur?

BACKGROUND

After stereotactic body radiotherapy (SBRT) to the lung, radiation pneumonitis and fibrotic changes often develop, and the tumor shadow usually becomes indistinguishable from the fibrotic shadow. Occasionally, however, a residual mass in patients with no or mild radiation pneumonitis will be observed on serial computed tomography (CT) scans. The purpose of the present study was to evaluate the fate of such residual masses and, if possible, to determine the types of tumor at increased risk of local recurrence.

PATIENTS AND METHODS

A total of 50 patients (underlying disease: primary lung cancer in 45, local recurrence in 2, and metastasis in 3) were selected because they had been followed up for > 2 years or until death and had observable CT changes and measurable tumor size for > 1 year, regardless of the influence of radiation pneumonitis. The patients' outcomes were compared according to various patient and tumor characteristics, including the presence and absence of emphysema, tumor size, and tumor shrinkage rate. The median follow-up period was 52 months.

RESULTS

Of the 50 patients, only 8 developed local recurrence. The local control rate was 81% at 3 years and 73% at 5 years. The local control rates were similar between patients with a high tumor shrinkage rate and those with a low rate. The patients with emphysema exhibited a lower local control rate.

CONCLUSION

The persistence of lung masses for > 1 year after SBRT is not necessarily indicative of an increased risk of local recurrence. A low tumor shrinkage rate also was not predictive of recurrence.

Stereotactic body radiation therapy for a new lung cancer arising after pneumonectomy: dosimetric evaluation and pulmonary toxicity

OBJECTIVE

To evaluate the tolerance of stereotactic body radiation therapy (SBRT) for the treatment of secondary lung tumours in patients who underwent previous pneumonectomy.

METHODS

12 patients were retrospectively analysed. The median maximum tumour diameter was 2.1 cm (1-4.5 cm). The median planning target volume was 20.7 cm(3) (2.4-101.2 cm(3)). Five patients were treated with a single fraction of 26 Gy and seven patients with fractionated schemes (3 × 10 Gy, 4 × 10 Gy, 4 × 12 Gy). Lung toxicity, correlated with volume (V) of lung receiving >5, >10 and >20 Gy, local control and survival rate were assessed. Median follow-up was 28 months.

RESULTS

None of the patients experienced pulmonary toxicity > grade 2 at the median dosimetric lung parameters of V5, V10 and V20 of 23.1% (range 10.7-56.7%), 7.3% (2.2-27.2%) and 2.7% (0.7-10.9%), respectively. No patients required oxygen or had deterioration of the performance status during follow-up if not as a result of clinical progression of disease. The local control probability at 2 years was 64.5%, and the overall survival at 2 years was 80%.

CONCLUSION

SBRT appears to be a safe and effective modality for treating patients with a second lung tumour after pneumonectomy.

ADVANCES IN KNOWLEDGE

Our results and similar literature results show that when keeping V5, V10 V20 <50%, <20% and <7%, respectively, the risk of significant lung toxicity is acceptable. Our experience also shows that biologically effective dose 10 >100 Gy, necessary for high local control rate, can be reached while complying with the dose constraints for most patients.

Pulmonary function and quality of life after VMAT-based stereotactic ablative radiotherapy for early stage inoperable NSCLC: a prospective study

OBJECTIVES

To analyze changes in pulmonary function and quality of life (QoL) at different time points after Stereotactic Ablative Radiotherapy (SABR) for early stage inoperable lung cancer, and potential correlations between radiation dose-volume parameters and pulmonary toxicity or changes in pulmonary function tests (PFT) and QoL.

MATERIALS AND METHODS

From July 2012 to October 2013, 30 patients were enrolled in this prospective observational study. Complete PFT were performed and Lung Cancer Symptoms Scale (LCSS) questionnaire administered prior to SABR; all patients then underwent Computed Tomography (CT) scan and PFT at 45, 135, 225 and 315 days after SABR, together with LCSS questionnaire. Clinical lung toxicity and radiological toxicity (acute and late) were prospectively recorded by using the Radiation Therapy Oncology Group (RTOG) scoring system.

RESULTS

A decline in Slow Vital Capacity (SVC), Forced Expiratory Volume in 1s (FEV1), Single-breath lung diffusing capacity (DLCO) and blood partial pressure of oxygen (PaO2) was seen at 135 days post-SABR. PaO2 values rescued to normal levels at 315 days. None of the baseline PFT parameters resulted to be associated with the occurrence of pulmonary toxicity or with late radiological changes. Mean V5, V10, and V20 and MLD2Gy were higher in patients who developed radiation pneumonitis, even if not significantly associated at Cox regression analysis. LCSS QoL showed a significant worsening of the single item fatigue at 135 days after SABR.

CONCLUSIONS

A small (mean 10%) but significant decline in lung volumes and DLCO was recorded after SABR, with clinical impact of such change difficult to estimate in individual patients. Global QoL was not significantly impaired. Dose-volume parameters did not emerge as significantly predictive of any clinical, radiological or functional toxicity.

Comparative effectiveness of surgery and radiosurgery for stage I non-small cell lung cancer

BACKGROUND

Although surgery is the standard treatment for early-stage non-small cell lung cancer (NSCLC), stereotactic body radiotherapy (SBRT) has been disseminated as an alternative therapy. The comparative mortalities and toxicities of these treatments for patients of different life expectancies are unknown.

METHODS

The Surveillance, Epidemiology, and End Results-Medicare linked database was used to identify patients who were 67 years old or older and underwent SBRT or surgery for stage I NSCLC from 2007 to 2009. Matched patients were stratified into short life expectancies (<5 years) and long life expectancies (≥5 years). Mortality and complication rates were compared with Poisson regression.

RESULTS

Overall, 367 SBRT patients and 711 surgery patients were matched. Acute toxicity (0-1 month) was lower from SBRT versus surgery (7.9% vs 54.9%, P < .001). At 24 months after treatment, there was no difference (69.7% vs 73.9%, P = .31). The incidence rate ratio (IRR) for toxicity from SBRT versus surgery was 0.74 (95% confidence interval [CI], 0.64-0.87). Overall mortality was lower with SBRT versus surgery at 3 months (2.2% vs 6.1%, P = .005), but by 24 months, overall mortality was higher with SBRT (40.1% vs 22.3%, P < .001). For patients with short life expectancies, there was no difference in lung cancer mortality (IRR, 1.01; 95% CI, 0.40-2.56). However, for patients with long life expectancies, there was greater overall mortality (IRR, 1.49; 95% CI, 1.11-2.01) as well as a trend toward greater lung cancer mortality (IRR, 1.63; 95% CI, 0.95-2.79) with SBRT versus surgery.

CONCLUSIONS

SBRT was associated with lower immediate mortality and toxicity in comparison with surgery. However, for patients with long life expectancies, there appears to be a relative benefit from surgery versus SBRT.

Long-term results of a prospective phase II trial of medically inoperable stage I NSCLC treated with SBRT - the Nordic experience

BACKGROUND

Presentation of long term results of a phase II multicenter Nordic trial of medically inoperable stage I non-small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT).

MATERIAL AND METHODS

We report the extended outcome, focusing on long-term effects, of a prospective cohort of 57 evaluable patients with peripherally located T1N0M0 (72%) and T2N0M0 (28%) NSCLC, treated with SBRT 15 Gy × 3, prescribed to the 67% isodose line encompassing the PTV. The patients were inoperable due to chronic obstructive pulmonary disease (65%), cardiovascular disease (25%) or other illnesses (3%) or refused surgery (7%). Median Karnofsky score pre-treatment was 80% (70-100%). Late effects were defined as occurring > 36 months.

RESULTS

Thirty-eight patients (67%) were relapse free during their entire follow-up. Local control rate at four and five years were 79% (CI 95% 64-95%) and local relapses occurred at 10-76 months post-treatment. Seven local failures were noted, four occurring ≤ 36 months (all T2a-tumors; two isolated and two in combination with out-of-field relapses) and three occurring > 36 months (T1b-tumors n = 3). Thirteen patients had out-of-field failure only as first presentation of recurrence. Overall survival rate and lung cancer-specific survival rate at five years were 30% and 74%, respectively. Toxicity throughout the entire observation period was acceptable without any grade 5 toxicities. Seventeen grade 3-4 toxicities were noted, three presenting > 36 months (rib fracture, dyspnea and ventricle tachycardia). Median follow-up was 41.5 months (3.4-113.0) for the entire cohort and 59.3 months (36.4-113.0) for the 34 patients (60%) with a follow-up of > 36 months.

CONCLUSION

Throughout the observation period local control was excellent and toxicity limited with no increase in late presenting local relapses or late treatment-related morbidity. This further supports SBRT as an efficient local treatment modality even in a medically impaired patient cohort.