Early Graphical Appearance of Radiation Pneumonitis Correlates With the Severity of Radiation Pneumonitis After Stereotactic Body Radiotherapy (SBRT) in Patients With Lung Tumors

Early Detection of Radiation Pneumonitis on Cone-Beam CT Images During a Course of Radiotherapy: A Case Series Report

Background and aim Radiation pneumonitis (RP) is a critical pulmonary toxicity following dose delivery to the lung, and it is usually diagnosed after radiotherapy courses are completed. Because RP may result in a lethal complication, a practical method for detecting early-phase RP is awaited. In this article, we describe our experience through a variety of clinical cases and discuss treatment decisions and lessons we have made and learned. Materials and methods A daily cone-beam computed tomography (CBCT) scan was employed with a lung window setting to detect the early-phase RP during treatment courses. For the past five years, thirty patients were diagnosed with RP, and eight patients were detected during radiotherapy courses on the CBCT images. Our best efforts were made in detecting early ground-glass opacity and early RP on CBCT images prior to symptoms. The eight cases were described in more detail with CBCT or CT images. Results and discussion Initially, RP was detected at 50 Gy or greater. However, more careful CBCT observation resulted in earlier detection at around 40 Gy. Then, a new problem arose whether the treatment should be terminated. It was reported that early RP development was associated with higher-grade complications, and therefore it is preferable to terminate radiotherapy once we detect even early-phase RP. However, termination in the middle of the treatment course may significantly reduce the therapeutic effect. In our experience, patients with favorable clinical status may continue to receive radiotherapy with careful observation of lung parenchyma on CBCT images and clinical data, such as Krebs Von den Lungen-6 (KL-6) and C-reactive protein (CRP). Conclusion We have shown that early detection of RP may be feasible during radiotherapy courses by daily monitoring of CBCT lung images. Further studies are awaited to proceed.

Longitudinal analyses and predictive factors of radiation-induced lung toxicity-related parameters after stereotactic radiotherapy for lung cancer

BACKGROUND AND PURPOSE

The purpose of this prospective study was to investigate changes in longitudinal parameters after stereotactic radiotherapy for lung cancer and to identify possible pretreatment factors related to radiation-induced lung toxicity and the decline in pulmonary function after radiotherapy.

MATERIALS AND METHODS

Protocol-specified examinations, including 4-D CT, laboratory tests, pulmonary function tests (PFTs) and body composition measurements, were performed before SRT and at 1 month, 4 months and 12 months after stereotactic radiotherapy. Longitudinal differences were tested by using repeated-measures analysis of variance. Correlations were examined by using the Pearson product-moment correlation coefficient (r).

RESULTS

Sixteen patients were analyzed in this study. During a median follow-up period of 26.6 months, grade 1 and 2 lung toxicity occurred in 11 patients and 1 patient, respectively. The mean Hounsfield units (HU) and standard deviation (SD) of the whole lung, as well as sialylated carbohydrate antigen KL-6 (KL-6) and surfactant protein-D (SP-D), peaked at 4 months after radiotherapy (p = 0.11, p<0.01, p = 0.04 and p<0.01, respectively). At 4 months, lung V20 Gy (%) and V40 Gy (%) were correlated with changes in SP-D, whereas changes in the mean HU of the lung were related to body mass index and lean body mass index (r = 0.54, p = 0.02; r = 0.57, p = 0.01; r = 0.69, p<0.01; and r = 0.69, p<0.01, respectively). The parameters of PFTs gradually declined over time. When regarding the change in PFTs from pretreatment to 12 months, lung V5 Gy (cc) showed significant correlations with diffusion capacity for carbon monoxide (DLCO), DLCO/alveolar volume and the relative change in DLCO (r = -0.72, p<0.01; r = -0.73, p<0.01; and r = -0.63, p = 0.01, respectively).

CONCLUSIONS

The results indicated that some parameters peaked at 4 months, but PFTs were the lowest at 12 months. Significant correlations between lung V5 Gy (cc) and changes in DLCO and DLCO/alveolar volume were observed.

Clinical Analysis of Severe Radiation Pneumonia

Objective

The present study aims to discuss the clinical characteristics, factors, and treatment methods affecting the prognosis in patients with severe radiation pneumonia (RP).

Methods

The radiotherapy status, clinical features, imaging characteristics, laboratory examination results, treatment methods, and prognoses of 34 patients with severe RP treated in our department between January 2011 and July 2017 were retrospectively analyzed. The severe RP grading was based on the Common Terminology Criteria for Adverse Events version 4.0; patients who scored Grade ≥3 were considered to have a severe case of RP.

Results

The results of the present study showed that 22 patients had lung cancer, 6 had esophageal cancer, 5 had breast cancer, and 1 had colon cancer with lung metastasis. The total radiation dose was 37.5–66 Gy, and the overall average dose was 53 Gy; the average dose in the patients who died was 52.9 Gy. A total of 28 patients presented with a cough and sputum as the initial symptom, and 24 presented with wheezing as an accompanying symptom; of the 24 patients, 8 experienced fever, 2 experienced wheezing as the only symptom, 1 had chest pain, and 1 had chest tightness. In 26 patients, the changes were in the radiation field, and in 8 cases, the changes appeared both inside and outside the radiation field. After the use of glucocorticoid methylprednisolone, respiratory support, and anti-infection treatment, 18 patients were cured, 8 showed a condition improvement, and 8 died.

Conclusion

The prognosis of severe RP was not significantly correlated with the administered radiation dose; however, lung cancer, a high Acute Physiology and Chronic Health Evaluation score, and delayed diagnosis were risk factors for patient death. However, a combination of antibiotic therapy, ventilator-assisted respiration, and steroid therapy could improve patient prognosis.

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.

Radiation-induced lung toxicity - cellular and molecular mechanisms of pathogenesis, management, and literature review

Lung, breast, and esophageal cancer represent three common malignancies with high incidence and mortality worldwide. The management of these tumors critically relies on radiotherapy as a major part of multi-modality care, and treatment-related toxicities, such as radiation-induced pneumonitis and/or lung fibrosis, are important dose limiting factors with direct impact on patient outcomes and quality of life. In this review, we summarize the current understanding of radiation-induced pneumonitis and pulmonary fibrosis, present predictive factors as well as recent diagnostic and therapeutic advances. Novel candidates for molecularly targeted approaches to prevent and/or treat radiation-induced pneumonitis and pulmonary fibrosis are discussed.

Radiation-induced lung toxicity predictors: Retrospective analysis of 90 patients treated with stereotactic body radiation therapy for stage I non-small-cell lung carcinoma

BACKGROUND

The main complication after hypofractionated radiotherapy for lung carcinoma is radiation-induced lung toxicity, which can be divided into radiation pneumonitis (acute toxicity, occurring within 6 months) and lung fibrosis (late toxicity, occurring after 6 months). The literature describes several predictive factors related to the patient, to the tumor (volume, central location), to the dosimetry and to biological factors.

MATERIALS AND METHODS

This study is a retrospective analysis of 90 patients treated with stereotactic body irradiation for stage I non-small-cell lung carcinoma between December 2010 and May 2015.

RESULTS

Radiation pneumonitis was observed in 61.5% of the patients who were mainly asymptomatic (34%). Chronic obstructive pulmonary disease was not predictive of radiation pneumonitis, whereas active smoking was protective. Centrally located tumors were not more likely to result in this complication if the radiation schedule utilized adapted fractionation. In our study, no predictive factor was identified. Whereas the mean lung dose was a predictive factor in 3D radiotherapy, the lung volume irradiated at high doses seemed to be involved in the pathogenesis after hypofractionated radiotherapy.

CONCLUSION

The discovery of predictive factors for radiation pneumonitis is difficult due to the rarity of this complication, especially with an 8×7.5Gy schedule. Radiation pneumonitis seems to be correlated with the volume irradiated at high doses, which is in contrast to the known knowledge about the organs in parallel. This finding leads us to raise the hypothesis that vessel damage, organs in series, occurring during hypofractionated radiotherapy could be responsible for this toxicity.

Correlation of dosimetric factors with the development of symptomatic radiation pneumonitis in stereotactic body radiotherapy

BACKGROUND

The development of radiation pneumonitis (RP) after Stereotactic Body Radiotherapy (SBRT) is known to be associated with many different factors, although historical analyses of RP have commonly utilized heterogeneous fractionation schemes and methods of reporting. This study aims to correlate dosimetric values and their association with the development of Symptomatic RP according to recent reporting standards as recommended by the American Association of Physicists in Medicine.

METHODS

We performed a single-institution retrospective review for patients who received SBRT to the lung from 2010 to 2017. Inclusion criteria required near-homogeneous tumoricidal (α/β = 10 Gy) biological effective dose (BED10) of 100-105 Gy (e.g., 50/5, 48/4, 60/8), one or two synchronously treated lesions, and at least 6 months of follow up or documented evidence of pneumonitis. Symptomatic RP was determined clinically by treating radiation oncologists, requiring radiographic evidence and the administration of steroids. Dosimetric parameters and patient factors were recorded. Lung volumes subtracted gross tumor volume(s). Wilcoxon Rank Sums tests were used for nonparametric comparison of dosimetric data between patients with and without RP; p-values were Bonferroni adjusted when applicable. Logistic regressions were conducted to predict probabilities of symptomatic RP using univariable models for each radiation dosimetric parameter.

RESULTS

The final cohort included 103 treated lesions in 93 patients, eight of whom developed symptomatic RP (n = 8; 8.6%). The use of total mean lung dose (MLD) > 6 Gy alone captured five of the eight patients who developed symptomatic RP, while V20 > 10% captured two patients, both of whom demonstrated a MLD > 6 Gy. The remaining three patients who developed symptomatic RP without exceeding either metric were noted to have imaging evidence of moderate interstitial lung disease, inflammation of the lungs from recent concurrent chemoradiation therapy to the contralateral lung, or unique peri-tumoral inflammatory appearance at baseline before treatment.

CONCLUSIONS

This study is the largest dosimetric analysis of symptomatic RP in the literature, of which we are aware, that utilizes near-homogenous tumoricidal BED fractionation schemes. Mean lung dose and V20 are the most consistently reported of the various dosimetric parameters associated with symptomatic RP. MLD should be considered alongside V20 in the treatment planning process.

TRIAL REGISTRATION

Retrospectively registered on IRB 398-17-EP.

Fractional exhaled nitric oxide as a potential biomarker for radiation pneumonitis in patients with non-small cell lung cancer: A pilot study

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Weekly FeNO during radiotherapy can be useful in predicting radiation pneumonitis.

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6 months of clinical follow-up is necessary to detect delayed radiation pneumonitis.

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Pulmonary function tests are not predictable for radiation pneumonitis.

Introduction

The aim of the study was to investigate repetitive fractional exhaled nitric oxide (FeNO) measurements during high-dose radiation therapy (HDRT) and to evaluate the use of FeNO to predict symptomatic radiation pneumonitis (RP) in patients being treated for non-small cell lung cancer (NSCLC).

Materials and methods

A total of 50 patients with NSCLC referred for HDRT were enrolled. FeNO was measured at baseline, weekly during HDRT, one month- and every third month after HDRT for a one-year follow-up period. The mean FeNO_{(visit 0-6)} was calculated using the arithmetic mean of the baseline and weekly measurements during HDRT. Patients with grade ≥ 2 of RP according to the Common Terminology Criteria for Adverse Events (CTCAE) were considered symptomatic.

Results

A total of 42 patients completed HDRT and weekly FeNO measurements. Grade ≥ 2 of RP was diagnosed in 24 (57%) patients. The mean FeNO_{(visit 0-6)} ± standard deviation in patients with and without RP was 15.0 ± 7.1 ppb (95%CI: 12.0–18.0) and 10.3 ± 3.4 ppb (95%CI: 8.6–11.9) respectively with significant differences between the groups (p = 0.0169, 95%CI: 2.3–2.6). The leave-one-out cross-validated cut-off value of the mean FeNO_{(visit 0-6)} ≥ 14.8 ppb was predictive of grade ≥ 2 RP with a specificity of 71% and a positive predictive value of 78%.

Conclusions

The mean FeNO_{(visit 0-6)} in patients with symptomatic RP after HDRT for NSCLC was significantly higher than in patients without RP and may serve as a potential biomarker for RP.

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.

Case Series of 23 Patients Who Developed Fatal Radiation Pneumonitis After Stereotactic Body Radiotherapy for Lung Cancer

The purpose of this study was to examine the characteristics and treatment plans of patients who experienced fatal radiation pneumonitis after stereotactic body radiation therapy for primary or oligometastatic lung cancer. Records of 1789 patients treated with stereotactic body radiation therapy for primary or oligometastatic lung cancer were retrospectively reviewed to identify those who developed fatal radiation pneumonitis. Twenty-three (1.3%; 18 men and 5 women) patients developed fatal radiation pneumonitis after stereotactic body radiation therapy for lung cancer; their median age was 74 years. The mean Krebs von den Lungen-6 level and percent vital capacity were 1320 U/mL and 82%, respectively. Prestereotactic body radiation therapy computed tomography revealed pulmonary interstitial change in 14 (73.7%) of 19 patients in whom computed tomography data could be reviewed. Seven (30.4%) of 23 patients had regularly used steroids. The median time duration between stereotactic body radiation therapy commencement and pneumonia symptom appearance was 75 (range: 14-204) days. Median survival time following pneumonia symptom appearance was 53 (range: 4-802) days. The 6- and 12-month overall survival rates were 34.8% and 13.0%, respectively. The 6-month overall survival rates in patients with and without heart disease were 50.0%, 16.7%, and 46.7% for heart disease existence, respectively. There were 4 patients in whom fatal radiation pneumonitis occurred within 2 months after stereotactic body radiation therapy and who died within 1 month. Three of them had no pulmonary interstitial change before stereotactic body radiation therapy, but had heart disease. In summary, the survival time in this case series was generally short but varied widely. More than half of the patients had pulmonary interstitial change before stereotactic body radiation therapy, although immediately progressive fatal radiation pneumonitis was also observed in patients without pulmonary interstitial change. True risk factors for fatal radiation pneumonitis should be examined in a prospective study with a larger cohort.

Organs at Risk Considerations for Thoracic Stereotactic Body Radiation Therapy: What Is Safe for Lung Parenchyma?

PURPOSE

Stereotactic body radiation therapy (SBRT) has become the standard of care for inoperable early-stage non-small cell lung cancer and is often used for recurrent lung cancer and pulmonary metastases. Radiation-induced lung toxicity (RILT), including radiation pneumonitis and pulmonary fibrosis, is a major concern for which it is important to understand dosimetric and clinical predictors.

METHODS AND MATERIALS

This study was undertaken through the American Association of Physicists in Medicine's Working Group on Biological Effects of Stereotactic Body Radiotherapy. Data from studies of lung SBRT published through the summer of 2016 that provided detailed information about RILT were analyzed.

RESULTS

Ninety-seven studies were ultimately considered. Definitions of the risk organ and complication endpoints as well as dose-volume information presented varied among studies. The risk of RILT, including radiation pneumonitis and pulmonary fibrosis, was reported to be associated with the size and location of the tumor. Patients with interstitial lung disease appear to be especially susceptible to severe RILT. A variety of dosimetric parameters were reported to be associated with RILT. There was no apparent threshold "tolerance dose-volume" level. However, most studies noted safe treatment with a rate of symptomatic RILT of <10% to 15% after lung SBRT with a mean lung dose (MLD) of the combined lungs ≤8 Gy in 3 to 5 fractions and the percent of total lung volume receiving more than 20 Gy (V₂₀) <10% to 15%.

CONCLUSIONS

To allow more rigorous analysis of this complication, future studies should standardize reporting by including standardized endpoint and volume definitions and providing dose-volume information for all patients, with and without RILT.

[Radiation-induced lung toxicity predictors after stereotactic radiation therapy for non-small cell lung carcinoma stage I]

In case of refusal or contraindication for surgical management of a stage I non-small cell lung carcinoma, the validated alternative therapy is stereotactic irradiation. This technique reaches an equivalent tumour control rate than surgery and significantly higher than conventional radiotherapy. One of the dreaded complications is radiation induced lung toxicity (radiation pneumonitis and lung fibrosis), especially when it is symptomatic, occurring in about 10 % of cases. This article is a literature review of this complication's predictive factors.

Technical Note: Identification of CT Texture Features Robust to Tumor Size Variations for Normal Lung Texture Analysis

Normal lung CT texture features have been used for the prediction of radiation-induced lung disease (RILD). For these features to be clinically useful, they should be robust to tumor size variations and not correlated with the normal lung volume of interest, i.e., the volume of the peri-tumoral region (PTR). CT images of 14 lung cancer patients were studied. Different sizes of gross tumor volumes (GTVs) were simulated and placed in the lung contralateral to the tumor. 27 texture features [nine from intensity histogram, eight from the gray-level co-occurrence matrix (GLCM) and ten from the gray-level run-length matrix (GLRM)] were extracted from the PTR. The Bland-Altman analysis was applied to measure the normalized range of agreement (nRoA) for each feature when GTV size varied. A feature was considered as robust when its nRoA was less than the threshold (100%). Sixteen texture features were identified as robust. None of the robust features was correlated with the volume of the PTR. No feature showed statistically significant differences (P<0.05) on GTV locations. We identified 16 robust normal lung CT texture features that can be further examined for the prediction of RILD.

Stereotactic Body Radiation Therapy for Patients with Pulmonary Interstitial Change: High Incidence of Fatal Radiation Pneumonitis in a Retrospective Multi-Institutional Study

Pretreatment pulmonary interstitial change (PIC) has been indicated as a risk factor of severe radiation pneumonitis (RP) following stereotactic body radiation therapy (SBRT) for early-stage lung cancer, but details of its true effect remain unclear. This study aims to evaluate treatment outcomes of SBRT for stage I non-small cell lung cancer in patients with PIC. A total of 242 patients are included in this study (88% male). The median age is 77 years (range, 55–92 years). A total dose of 40–70 Gy is administered in 4 to 10 fractions during a 4-to-25 day period. One, two, and three-year overall survival (OS) rates are 82.1%, 57.1%, and 42.6%, respectively. Fatal RP is identified in 6.9% of all patients. The percent vital capacity <70%, mean percentage normal lung volume receiving more than 20 Gy (>10%), performance status of 2–4, presence of squamous cell carcinoma, clinical T2 stage, regular use of steroid before SBRT, and percentage predicting forced expiratory volume in one second (<70%) are associated with worse prognoses for OS. Our results indicate that fatal RP frequently occurs after SBRT for stage I lung cancer in patients with PIC.

Lung density change after SABR: A comparative study between tri-Co-60 magnetic resonance-guided system and linear accelerator

Radiation-induced lung damage is an important treatment-related toxicity after lung stereotactic ablative radiotherapy (SABR). After implementing a tri-⁶⁰Co magnetic-resonance image guided system, ViewRay^TM, we compared the associated early radiological lung density changes to those associated with a linear accelerator (LINAC). Eight patients treated with the tri-⁶⁰Co system were matched 1:1 with patients treated with LINAC. Prescription doses were 52 Gy or 60 Gy in four fractions, and lung dose-volumetric parameters were calculated from each planning system. The first two follow-up computed tomography (CT) were co-registered with the planning CT through deformable registration software, and lung density was measured by isodose levels. Tumor size was matched between the two groups, but the planning target volume of LINAC was larger than that of the tri-⁶⁰Co system (p = 0.036). With regard to clinically relevant dose-volumetric parameters in the lungs, the ipsilateral lung mean dose, V_10Gy and V_20Gy were significantly poorer in tri-⁶⁰Co plans compared to LINAC plans (p = 0.012, 0.036, and 0.017, respectively). Increased lung density was not observed in the first follow-up scan compared to the planning scan. A significant change of lung density was shown in the second follow-up scan and there was no meaningful difference between the tri-⁶⁰Co system and LINAC for all dose regions. In addition, no patient developed clinical radiation pneumonitis until the second follow-up scan. Therefore, there was no significant difference in the early radiological lung damage between the tri-⁶⁰Co system and LINAC for lung SABR despite of the inferior plan quality of the tri-⁶⁰Co system compared to that of LINAC. Further studies with a longer follow-up period are needed to confirm our findings.

Clarithromycin mitigates radiation pneumonitis in patients with lung cancer treated with stereotactic body radiotherapy

Background

Radiation pneumonitis is a critical pulmonary toxicity after irradiation of the lung. Macrolides including clarithromycin (CAM) are antibiotics. They also have immunomodulatory properties and are used to treat respiratory inflammatory diseases. Radiation pneumonitis has similar pathology to them. Adverse reactions to macrolides are few and self-limited. We thus administered CAM to patients with high-risk factors for radiation pneumonitis, and retrospectively investigated whether CAM mitigated radiation pneumonitis following stereotactic body radiotherapy (SBRT).

Methods

Among consecutive patients treated with SBRT, we retrospectively examined lung cancer patients treated with a total dose of 40-60 Gy in 5-10 fractions and followed ≥6 months. Since January 2014, CAM has been administered in patients with pretreatment predictable radiation pneumonitis high-risk factors, including idiopathic interstitial pneumonias (IIPs), and elevated Krebs von den Lungen-6 (KL-6) and/or surfactant protein D (SP-D), and in patients developing early onset radiation pneumonitis.

Results

Five hundred and eighty eligible patients were identified and divided into 445 patients during the non-CAM-administration era (non-CAM-era) (before December 2013) and 136 patients during the CAM-administration era (CAM-era) (after January 2014). Median follow-up durations were 38.0 and 13.9 months, respectively. The rates of radiation pneumonitis ≥ grade 2 and ≥ grade 3 were significantly lower in CAM-era (grade ≥2, 16% vs. 9.6%, P=0.047; grade ≥3, 3.8% vs. 0.73%, P=0.037). For patients with the pretreatment predictable high-risk factors, the rate of radiation pneumonitis ≥ grade 3 was significantly lower, and that of grade ≥2 had a lower tendency (grade ≥3, 7.2% vs. 0%, P=0.011; grade ≥2, 21% vs. 9.6%, P=0.061). For patients developing early onset radiation pneumonitis, the rate of radiation pneumonitis ≥ grade 3 was also significantly lower (23% vs. 0%, P<0.05). Multivariate analysis revealed that dose-volumetric factor, the pretreatment predictable high-risk factors and non-CAM-administration era were significantly associated with or trended toward radiation pneumonitis ≥ grade 2 and ≥ grade 3.

Conclusions

CAM mitigated radiation pneumonitis following SBRT. The efficacy of CAM should be confirmed in prospective studies.

Neutrophil-lymphocyte ratio and a dosimetric factor for predicting symptomatic radiation pneumonitis in non-small-cell lung cancer patients treated with concurrent chemoradiotherapy

OBJECTIVES

To identify the factors that predict the progression of radiological radiation pneumonitis (RP) to symptomatic RP, and to evaluate the usefulness of the neutrophil-lymphocyte ratio (NLR) as a marker of RP severity and prognosis in stage III non-small cell lung cancer (NSCLC) patients treated with definitive concurrent chemoradiotherapy (CCRT).

MATERIALS AND METHODS

We retrospectively reviewed 61 patients treated between January 2010 and December 2015. Patients' demographic characteristics, clinical data, laboratory findings and treatment parameters were analyzed to determine the predictive factors associated with progression from radiological RP to symptomatic RP.

RESULTS

Forty-seven patients (77%) exhibited radiological RP at a median of 78 days after radiation therapy (RT) completion, and 15 (32%) of these patients developed symptomatic RP. The interval between RT completion and radiological RP presentation was shorter in patients who progressed to symptomatic RP (P = .001); progression was highly probable if this latency period was ≤2 months (P = .002). Stage and RT technique correlated with symptomatic RP development (P = .046 and P = .046, respectively). Among dosimetric factors, a V₂₀ (defined as the lung volume receiving ≥20 Gy) of >30% was the most significant predictor of symptomatic RP (P = .001). The NLR and C-reactive protein level at radiological RP were higher in patients who developed symptomatic RP (P = .067 and P = .012, respectively). On multivariate analysis, a V₂₀ >30% and an NLR at radiological RP >6 were associated with symptomatic RP development.

CONCLUSION

The NLR at radiological RP is a useful biomarker for predicting symptomatic RP development after CCRT in stage III NSCLC patients.

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.

Complications from Stereotactic Body Radiotherapy for Lung Cancer

Stereotactic body radiotherapy (SBRT) has become a standard treatment option for early stage, node negative non-small cell lung cancer (NSCLC) in patients who are either medically inoperable or refuse surgical resection. SBRT has high local control rates and a favorable toxicity profile relative to other surgical and non-surgical approaches. Given the excellent tumor control rates and increasing utilization of SBRT, recent efforts have focused on limiting toxicity while expanding treatment to increasingly complex patients. We review toxicities from SBRT for lung cancer, including central airway, esophageal, vascular (e.g., aorta), lung parenchyma (e.g., radiation pneumonitis), and chest wall toxicities, as well as radiation-induced neuropathies (e.g., brachial plexus, vagus nerve and recurrent laryngeal nerve). We summarize patient-related, tumor-related, dosimetric characteristics of these toxicities, review published dose constraints, and propose strategies to reduce such complications.

Timing and characteristics of radiation pneumonitis after stereotactic body radiotherapy for peripherally located stage I lung cancer

BACKGROUND

This study was conducted to determine the timing and characteristics of radiation pneumonitis (RP) associated with stereotactic body radiotherapy (SBRT) for stage I lung cancer.

METHODS

Two hundred thirty-one patients treated with SBRT using 52 Gy in 4 fractions were identified. Control rate, RP incidence rate, and predictive factors and timing of RP were evaluated retrospectively.

RESULTS

The 3-year overall survival and local control rates were 80.7 and 92.0 %, respectively. The grade ≥2 RP rate was 13.0 %; no grade 4-5 RP occurred. The most statistically significant predictive factor of grade ≥2 RP was V10. The median intervals to first graphical appearance were 4.2 and 2.5 months for grade 1 and grade 2-3 RP, respectively. Median intervals to maximum radiological density change were 6.0 and 4.6 months for grade 1 and grade 2-3 RP, respectively. A significantly different interval to first graphical appearance between grade 1 and grade 2-3 RP was observed; no significantly different interval to maximum radiological density change was noted.

CONCLUSIONS

The first graphical appearance of grade ≥2 RP was earlier than that of grade 1 RP, although the timing of maximum radiological density change was not significantly different.

Radiation pneumonitis after stereotactic radiation therapy for lung cancer

Stereotactic body radiation therapy (SBRT) has a local control rate of 95% at 2 years for non-small cell lung cancer (NSCLC) and should improve the prognosis of inoperable patients, elderly patients, and patients with significant comorbidities who have early-stage NSCLC. The safety of SBRT is being confirmed in international, multi-institutional Phase II trials for peripheral lung cancer in both inoperable and operable patients, but reports so far have found that SBRT is a safe and effective treatment for early-stage NSCLC and early metastatic lung cancer. Radiation pneumonitis (RP) is one of the most common toxicities of SBRT. Although most post-treatment RP is Grade 1 or 2 and either asymptomatic or manageable, a few cases are severe, symptomatic, and there is a risk for mortality. The reported rates of symptomatic RP after SBRT range from 9% to 28%. Being able to predict the risk of RP after SBRT is extremely useful in treatment planning. A dose-effect relationship has been demonstrated, but suggested dose-volume factors like mean lung dose, lung V20, and/or lung V2.5 differed among the reports. We found that patients who present with an interstitial pneumonitis shadow on computed tomography scan and high levels of serum Krebs von den Lungen-6 and surfactant protein D have a high rate of severe radiation pneumonitis after SBRT. At our institution, lung cancer patients with these risk factors have not received SBRT since 2006, and our rate of severe RP after SBRT has decreased significantly since then.

[Radiation pneumonitis after stereotactic body radiation therapy for early stage non-small cell lung cancer]

With the development of radiation technology, stereotactic body radiation therapy (SBRT) has been widely used in early stage non-small cell lung cancer (NSCLC). It is not only the standard therapy for medically inoperable early-stage NSCLC, but also one of the therapies for operable early-stage NSCLC. Radiation pneumonitis (RP) is one of the most common adverse effects after SBRT, it may reduce the patients' quality of life, even cause treatment failure. Therefore, in order to improve the patients' quality of life and enhance local control rate of tumor, it is important to reduce the risk of RP. The unique fractionation schemes and the dose distribution of SBRT make it not only different from conventional fraction radiation therapy in treatment outcomes, but also in the incidence of radiation pneumonitis. This article reviews the applying of SBRT for early stage NSCLC, the incidence of radiation pneumonitis, radiological appearance after SBRT and predictive factors.

Development of radiation pneumopathy and generalised radiological changes after radiotherapy are independent negative prognostic factors for survival in non-small cell lung cancer patients

BACKGROUND AND PURPOSE

To investigate the risk factors for radiation pneumopathy (RP) and survival rate of non-small cell lung cancer patients with RP and generalised interstitial lung changes (gen-ILC).

MATERIAL AND METHODS

A total of 147 consecutive patients receiving curative radiotherapy were analysed. RP was graded according to Common Terminology Criteria for Adverse Events v. 3. Computed tomography images were assessed for the presence of gen-ILC after radiotherapy. Univariate and multivariate analyses were performed to identify significant factors.

RESULTS

Median follow-up was 16.2 months (range 1.4-58.6). Radiological changes after radiotherapy were confined to high dose irradiation volume in 111 patients, while 31 patients developed gen-ILC. Dosimetric parameters and level of C-reactive protein before radiotherapy were significantly associated with severe RP. Development of gen-ILC (p=0.008), as well as severe RP (p=0.03) had significant negative impact on patients' survival. These two factors remained significant in the multivariate analysis.

CONCLUSIONS

Severe radiation pneumopathy and generalised radiographic changes were significant independent prognostic factors for survival. More studies on pathophysiology of radiation induced damage are necessary to fully understand the mechanisms behind it.

Rib fracture after stereotactic radiotherapy for primary lung cancer: prevalence, degree of clinical symptoms, and risk factors

Background

As stereotactic body radiotherapy (SBRT) is a highly dose-dense radiotherapy, adverse events of neighboring normal tissues are a major concern. This study thus aimed to clarify the frequency and degree of clinical symptoms in patients with rib fractures after SBRT for primary lung cancer and to reveal risk factors for rib fracture. Appropriate α/β ratios for discriminating between fracture and non-fracture groups were also investigated.

Methods

Between November 2001 and April 2009, 177 patients who had undergone SBRT were evaluated for clinical symptoms and underwent follow-up thin-section computed tomography (CT). The time of rib fracture appearance was also assessed. Cox proportional hazard modeling was performed to identify risk factors for rib fracture, using independent variables of age, sex, maximum tumor diameter, radiotherapeutic method and tumor-chest wall distance. Dosimetric details were analyzed for 26 patients with and 22 randomly-sampled patients without rib fracture. Biologically effective dose (BED) was calculated with a range of α/β ratios (1–10 Gy). Receiver operating characteristics analysis was used to define the most appropriate α/β ratio.

Results

Rib fracture was found on follow-up thin-section CT in 41 patients. The frequency of chest wall pain in patients with rib fracture was 34.1% (14/41), and was classified as Grade 1 or 2. Significant risk factors for rib fracture were smaller tumor-chest wall distance and female sex. Area under the curve was maximal for BED at an α/β ratio of 8 Gy.

Conclusions

Rib fracture is frequently seen on CT after SBRT for lung cancer. Small tumor-chest wall distance and female sex are risk factors for rib fracture. However, clinical symptoms are infrequent and generally mild. When using BED analysis, an α/β ratio of 8 Gy appears most effective for discriminating between fracture and non-fracture patients.

Clinical and dosimetric predictors of radiation pneumonitis in a large series of patients treated with stereotactic body radiation therapy to the lung

PURPOSE

To report clinical and dosimetric factors predictive of radiation pneumonitis (RP) in patients receiving lung stereotactic body radiation therapy (SBRT) from a series of 240 patients.

METHODS AND MATERIALS

Of the 297 isocenters treating 263 patients, 240 patients (n=263 isocenters) had evaluable information regarding RP. Age, gender, current smoking status and pack-years, O2 use, Charlson Comorbidity Index, prior lung radiation therapy (yes/no), dose/fractionation, V5, V13, V20, Vprescription, mean lung dose, planning target volume (PTV), total lung volume, and PTV/lung volume ratio were recorded.

RESULTS

Twenty-nine patients (11.0%) developed symptomatic pneumonitis (26 grade 2, 3 grade 3). The mean V20 was 6.5% (range, 0.4%-20.2%), and the average mean lung dose was 5.03 Gy (0.547-12.2 Gy). In univariable analysis female gender (P=.0257) and Charlson Comorbidity index (P=.0366) were significantly predictive of RP. Among dosimetric parameters, V5 (P=.0186), V13 (P=.0438), and Vprescription (where dose=60 Gy) (P=.0128) were significant. There was only a trend toward significance for V20 (P=.0610). Planning target volume/normal lung volume ratio was highly significant (P=.0024). In multivariable analysis the clinical factors of female gender, pack-years smoking, and larger gross internal tumor volume and PTV were predictive (P=.0094, .0312, .0364, and .052, respectively), but no dosimetric factors were significant.

CONCLUSIONS

Rate of symptomatic RP was 11%. Our mean lung dose was <600 cGy in most cases and V20<10%. In univariable analysis, dosimetric factors were predictive, while tumor size (or tumor/lung volume ratio) played a role in multivariable and univariable and analysis, respectively.

Dose--volume metrics associated with radiation pneumonitis after stereotactic body radiation therapy for lung cancer

PURPOSE

To identify dose-volume factors associated with radiation pneumonitis (RP) after stereotactic body radiation therapy (SBRT) for lung cancer.

METHODS AND MATERIALS

This study analyzed 74 patients who underwent SBRT for primary lung cancer. The prescribed dose for SBRT was uniformly 48 Gy in four fractions at the isocenter. RP was graded according to the Common Terminology Criteria for Adverse Events (CTCAE) v.3. Symptomatic RP was defined as grade 2 or worse. Optimal cut-offs dividing the patient population into two subgroups based on the incidence of symptomatic RP were sought using the following dose-volume metrics: PTV volume (ml), mean lung dose (Gy), and V5, V10, V15, V20, V25, V30, V35, and V40 (%) of both lungs excluding the PTV.

RESULTS

With a median follow-up duration of 31.4 months, symptomatic RP was observed in 15 patients (20.3%), including 1 patient with grade 3. Optimal cut-offs for pulmonary dose-volume metrics were V25 and V20. These two factors were highly correlated with each other, and V25 was more significant. Symptomatic RP was observed in 14.8% of the patients with V25 <4.2%, and the rate was 46.2% in the remainder (p = 0.019). PTV volume was another significant factor. The symptomatic RP rate was significantly lower in the group with PTV <37.7 ml compared with the larger PTV group (11.1% vs. 34.5%, p = 0.020). The patients were divided into three subgroups (patients with PTV <37.7 ml; patients with, PTV ≥37.7 ml and V25 <4.2%; and patients with PTV ≥37.7 ml and V25 ≥4.2%); the incidence of RP grade 2 or worse was 11.1%, 23.5%, and 50.0%, respectively (p = 0.013).

CONCLUSIONS

Lung V25 and PTV volume were significant factors associated with RP after SBRT.

Comparison of clinical, tumour-related and dosimetric factors in grade 0-1, grade 2 and grade 3 radiation pneumonitis after stereotactic body radiotherapy for lung tumours

OBJECTIVE

The aim of this study was to investigate significant clinical, tumour-related and dosimetric factors among patients with grade 0-1, grade 2 and grade 3 radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT) for lung tumours.

METHODS

Patients (n=128) with a total of 133 lung tumours treated with SBRT of 50 Gy in 5 fractions were analysed. RP was graded according to the Common Terminology Criteria for Adverse Events v.3.0. Significant factors were identified by univariate and multivariate analyses. Threshold dose-volume histograms (DVHs) were constructed to identify the incidence of RP.

RESULTS

The median follow-up period was 12 months (range, 6-45 months). In univariate analyses, gender, operability, forced expiratory volume in 1 s (FEV1), internal target volume, lung volumes treated with doses >5-30 Gy (V5-30) and mean lung dose were significant factors differentiating between grade 0-1 and grade 2 RP, and V15-30 were significant factors differentiating between grade 2 and grade 3. However, no factors were significant between grade 0-1 and grade 3 RP. Multivariate analysis showed that female gender, high FEV1 and high V15 were significant factors differentiating between grade 0-1 and grade 2 RP. Threshold DVH curves were created based on ≤5% and ≤15% risk of grade 2 RP among patients with grade 0-2 RP.

CONCLUSIONS

Grade 0-2 RP was dose-volume dependent, and female gender and high FEV1 were significant predictive clinical factors for grade 2 RP among patients with grade 0-2 RP. However, incidences of V15-30 in grade 3 RP were significantly lower than those in grade 2 RP, and no significant clinical or tumour-related factors were found. Further studies are needed to identify the mechanism underlying the development of grade 3 RP after SBRT for lung tumours.

Association of computed tomography-detected pulmonary interstitial changes with severe radiation pneumonitis for patients treated with thoracic radiotherapy

We evaluated associations of interstitial changes with radiation pneumonitis (RP) for patients treated with thoracic radiotherapy. Between 2005 and 2009, patients who received thoracic radiotherapy of 40 Gy or more for lung cancer or thymic tumors and were followed-up for more than 6 months were eligible for this study. Possible risk factors for RP included the presence of interstitial changes on computed tomography before radiotherapy, and elevated C-reactive protein (CRP) and lactate dehydrogenase (LDH) levels; these were compared with the incidences of severe RP. A total of 106 patients were included. The incidences of RP were 4 (4%), 0 (0%), and 5 (5%) for grades 3, 4, and 5, respectively. For those with interstitial changes, the incidence of RP ≥ grade 3 was significantly increased from 3% (2/79) to 26% (7/27) (p < 0.001). CRP and LDH levels were also associated with increased RP, as were pulmonary emphysema and performance status ≥ 2. Among 91 patients with RP ≥ grade 1, RP grade ≥ 3 occurred significantly earlier than grades 1 and 2. In conclusion, pulmonary interstitial changes, LDH and CRP levels, pulmonary emphysema, and performance status ≥ 2 were significantly associated with RP ≥ grade 3. RP grade ≥ 3 occurred significantly earlier than grades 1 and 2. The early appearance of interstitial changes requires careful management due to the possibility of severe RP.

Rib fracture after stereotactic radiotherapy on follow-up thin-section computed tomography in 177 primary lung cancer patients

Background

Chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer has recently been reported. However, its detailed imaging findings are not clarified. So this study aimed to fully characterize the findings on computed tomography (CT), appearance time and frequency of chest wall injury after stereotactic radiotherapy (SRT) for primary lung cancer

Materials and methods

A total of 177 patients who had undergone SRT were prospectively evaluated for periodical follow-up thin-section CT with special attention to chest wall injury. The time at which CT findings of chest wall injury appeared was assessed. Related clinical symptoms were also evaluated.

Results

Rib fracture was identified on follow-up CT in 41 patients (23.2%). Rib fractures appeared at a mean of 21.2 months after the completion of SRT (range, 4 -58 months). Chest wall edema, thinning of the cortex and osteosclerosis were findings frequently associated with, and tending to precede rib fractures. No patients with rib fracture showed tumors > 16 mm from the adjacent chest wall. Chest wall pain was seen in 18 of 177 patients (10.2%), of whom 14 patients developed rib fracture. No patients complained of Grade 3 or more symptoms.

Conclusion

Rib fracture is frequently seen after SRT for lung cancer on CT, and is often associated with chest wall edema, thinning of the cortex and osteosclerosis. However, related chest wall pain is less frequent and is generally mild if present.

Early pulmonary toxicity following lung stereotactic body radiation therapy delivered in consecutive daily fractions

BACKGROUND AND PURPOSE

Identify the incidence of early pulmonary toxicity in a cohort of patients treated with lung stereotactic body radiation therapy (SBRT) on consecutive treatment days.

MATERIAL AND METHODS

A total of 88 lesions in 84 patients were treated with SBRT in consecutive daily fractions (Fx) for medically inoperable non-small cell lung cancer or metastasis. The incidence of pneumonitis was evaluated and graded according to the NCI CTCAE v3.0.

RESULTS

With a median follow-up of 15.8 months (range 2.5-28.6), the median age at SBRT was 71.8 years (range 23.8-87.8). 47 lesions were centrally located and 41 were peripheral. Most central lesions were treated with 48Gy in 4 Fx, and most peripheral lesions with 54Gy in 3 Fx. The incidence of grade ≥ 2 pneumonitis was 12.5% in all patients treated, and 14.3% among the subset of patients treated with 54Gy in 3 Fx. A total of two grade 3 toxicities were seen as one grade 5 toxicity in a patient treated for recurrence after pneumonectomy.

CONCLUSIONS

Treating both central and peripheral lung lesions with SBRT in consecutive daily fractions in this cohort was well tolerated and did not cause excessive early pulmonary toxicity.

Treatment of large stage I-II lung tumors using stereotactic body radiotherapy (SBRT): planning considerations and early toxicity

PURPOSE

To study the dosimetric predictors of early clinical toxicity following SBRT in patients with lung tumors and planning target volumes (PTV) exceeding 80 cm(3).

METHODS

Eighteen consecutive patients who were treated using volumetric modulated arc therapy (RapidArc™) were assessed. All were either unfit or refused to undergo surgery or chemoradiotherapy. PTV planning objectives were as used in the ROSEL study protocol. Clinical toxicity was scored using Common Toxicity Criteria AE4.0. Lung volumes receiving 5, 10, 15, and 20 Gy (V(5), V(10), V(15) and V(20)) and mean lung dose were assessed and correlated to symptomatic radiation pneumonitis (RP).

RESULTS

Median age, age-adjusted Charlson-comorbidity score and PTV size were 74, 7.5 and 137 cm(3), respectively. At a median follow-up of 12.8 months, 8 deaths were recorded: 5 arising from comorbidity, 2 were potentially treatment-related and 1 had local recurrence. RP was reported in 5 patients (grade 2 in 3 and grade 3 in 2). All RP occurred in plans without a high priority optimization objective on contralateral lung. Acute RP was best predicted by contralateral lung V(5) (p<0.0001).

CONCLUSION

After SBRT using RapidArc in lung tumors >80 cm(3), the contralateral lung V(5) best predicts RP. Limiting contralateral lung V(5) to <26% may reduce acute toxicity.