Immune Responses following Stereotactic Body Radiotherapy for Stage I Primary Lung Cancer

Purpose. Immune responses following stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) were examined from the point of view of lymphocyte subset counts and natural killer cell activity (NKA). Patients and Methods. Peripheral blood samples were collected from 62 patients at 4 time points between pretreatment and 4 weeks post-treatment for analysis of the change of total lymphocyte counts (TLC) and lymphocyte subset counts of CD3 + , CD4 + , CD8 + , CD19 + , CD56 + , and NKA. In addition, the changes of lymphocyte subset counts were compared between patients with or without relapse. Further, the correlations between SBRT-related parameters and immune response were analyzed for the purpose of revealing the mechanisms of the immune response. Results. All lymphocyte subset counts and NKA at post-treatment and 1 week post-treatment were significantly lower than pre-treatment ( < 0.01). No significant differences in the changes of lymphocyte subset counts were observed among patients with or without relapse. The volume of the vertebral body receiving radiation doses of 3 Gy or more (VV 3 ) significantly correlated with the changes of nearly all lymphocyte subset counts. Conclusions. SBRT for stage I NSCLC induced significant immune suppression, and the decrease of lymphocyte subset counts may be associated with exposure of the vertebral bone marrow

Quantification of image quality of intra-fractional cone-beam computed tomography for arc irradiation with various imaging condition

BACKGROUND: 3-dimensional intra-cone beam computed tomography (intra-CBCT) could be a potentially powerful tool for use with arc irradiation such as volumetric modulated arc therapy. The aim of the study was to evaluate the image quality of intra-cone beam computed tomography (intra-CBCT) for arc irradiation with various imaging condition. MATERIALS AND METHODS: Two types of intra-CBCT imaging techniques were evaluated — intra-fractional CBCT with flattening filtered (FF) beam (intra-FF CBCT) and that with flattening filter free (FFF) beam (intra-FFF CBCT). For the intra-MV beams, four different field sizes (2 cm x 2 cm, 5 cm x 5 cm, 10 cm x 10 cm, and 20 cm x 20 cm) were used with dose rates of 500 MU/min and 1600 MU/min, for 6 MV FF and 6 MV FFF, respectively. For all image acquisitions, two rotation angles (full-arc and half-arc) were investigated. Thereafter, the linearity, contrast-to-noise ratio (CNR), and uniformity index (UI) of intra-CBCT image were compared with those of conventional CBCT image. RESULTS: All acquisition conditions had good linearity of the CT value (R2 > 0.99). For CNR, the change rates from conventional CBCT ranged from 0.6–33.7% for a 2 cm x 2 cm beam, whereas that for a 20 cm x 20 cm beam ranged from 62.7–82.3%. Similarly, the UI increased from 1.5% to 7.0% as the field size increased. CONCLUSION: Quality of intra-CBCT image was affected by the field size and acquisition angle. Image quality of intra-CBCT was worse than that of conventional CBCT, but it was better under a smaller field and wider correction angle and would be acceptable for clinical use.

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

<p>Abstract</p> <p>Background</p> <p>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</p> <p>Materials and methods</p> <p>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.</p> <p>Results</p> <p>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.</p> <p>Conclusion</p> <p>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.</p

Immune Responses following Stereotactic Body Radiotherapy for Stage I Primary Lung Cancer

Purpose. Immune responses following stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) were examined from the point of view of lymphocyte subset counts and natural killer cell activity (NKA). Patients and Methods. Peripheral blood samples were collected from 62 patients at 4 time points between pretreatment and 4 weeks post-treatment for analysis of the change of total lymphocyte counts (TLC) and lymphocyte subset counts of CD3+, CD4+, CD8+, CD19+, CD56+, and NKA. In addition, the changes of lymphocyte subset counts were compared between patients with or without relapse. Further, the correlations between SBRT-related parameters and immune response were analyzed for the purpose of revealing the mechanisms of the immune response. Results. All lymphocyte subset counts and NKA at post-treatment and 1 week post-treatment were significantly lower than pre-treatment (P<0.01). No significant differences in the changes of lymphocyte subset counts were observed among patients with or without relapse. The volume of the vertebral body receiving radiation doses of 3 Gy or more (VV3) significantly correlated with the changes of nearly all lymphocyte subset counts. Conclusions. SBRT for stage I NSCLC induced significant immune suppression, and the decrease of lymphocyte subset counts may be associated with exposure of the vertebral bone marrow

Impact of Systemic Autoimmune Diseases on Treatment Outcomes and Radiation Toxicities in Patients with Stage I Non-Small Cell Lung Cancer Receiving Stereotactic Body Radiation Therapy: A Matched Case-Control Analysis

We aimed to evaluate the impact of systemic autoimmune diseases (SADs) on treatment outcomes and radiation toxicities following stereotactic body radiation therapy (SBRT) for stage I non-small cell lung cancer (NSCLC). We queried an institution-based database on patients with SADs treated with SBRT for lung cancer between 2001 and 2016 (SAD group). Each patient was matched to three controls without SADs. The primary outcomes of interest were the overall survival (OS) and local control rate (LCR). The secondary outcomes were radiation toxicities of grades ≥2 (≥G2). Twelve patients with SADs were matched to 36 controls. The median follow-up duration was 3.6 years. There was a significant intergroup difference in the OS (hazard ratio [HR]: 4.11, 95% confidence incidence [CI]: 1.82–9.27, p p p = 0.550) and late (OR: 2.20, 95% CI: 0.32–15.10, p = 0.422) ≥G2 radiation pneumonitis. No other ≥G2 toxicities were identified. In conclusion, although radiation toxicities are not enhanced by SADs, SADs are risk factors of poor prognosis following SBRT for stage I NSCLC

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&ndash;92 years). A total dose of 40&ndash;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 &lt;70%, mean percentage normal lung volume receiving more than 20 Gy (&gt;10%), performance status of 2&ndash;4, presence of squamous cell carcinoma, clinical T2 stage, regular use of steroid before SBRT, and percentage predicting forced expiratory volume in one second (&lt;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