Stereotactic Body Radiotherapy For Stage Research Articles

Optimizing the flattening filter free beam selection in RapidArc®-based stereotactic body radiotherapy for Stage I lung cancer.

To optimize the flattening filter-free (FFF) beam selection in stereotactic body radiotherapy (SBRT) treatment for Stage I lung cancer in different fraction schemes. Treatment plans from 12 patients suffering from Stage I lung cancer were designed using the 6XFFF and 10XFFF beams in different fraction schemes of 4 × 12, 3 × 18 and 1 × 34 Gy. Plans were evaluated mainly in terms of organs at risk (OARs) sparing, normal tissue complication probability (NTCP) estimation and treatment efficiency. Compared with the 10XFFF beam, 6XFFF beam showed statistically significant lower dose to all the OARs investigated. The percentage of NTCP reduction for both lung and chest wall was about 10% in the fraction schemes of 4 × 12 and 3 × 18 Gy, whereas only 7.4% and 2.6% was obtained in the 1 × 34 Gy scheme. For oesophagus, heart and spinal cord, the reduction was greater with the 6XFFF beam, but their absolute estimates were <10(-6)%. The mean beam-on time for 6XFFF and 10XFFF beams at 4 × 12, 3 × 18 and 1 × 34 Gy schemes were 2.2 ± 0.2 vs 1.5 ± 0.1, 3.3 ± 0.9 vs 2.0 ± 0.5 and 6.3 ± 0.9 vs 3.5 ± 0.4 min, respectively. The 6XFFF beam obtains better OARs sparing and lower incidence of NTCP in SBRT treatment of Stage I lung cancer, whereas the 10XFFF beam improves the treatment efficiency. To balance the OARs sparing and intrafractional variation owing to the prolonged treatment time, the authors recommend using the 6XFFF beam in the 4 × 12 and 3 × 18 Gy schemes but the 10XFFF beam in the 1 × 34 Gy scheme. This study optimizes the FFF beam selection in different fraction schemes in SBRT treatment of Stage I lung cancer.

SU‐E‐T‐630: Predictive Modeling of Mortality, Tumor Control, and Normal Tissue Complications After Stereotactic Body Radiotherapy for Stage I Non‐Small Cell Lung Cancer

Purpose:While rates of local control have been well characterized after stereotactic body radiotherapy (SBRT) for stage I non‐small cell lung cancer (NSCLC), less data are available characterizing survival and normal tissue toxicities, and no validated models exist assessing these parameters after SBRT. We evaluate the reliability of various machine learning techniques when applied to radiation oncology datasets to create predictive models of mortality, tumor control, and normal tissue complications.Methods:A dataset of 204 consecutive patients with stage I non‐small cell lung cancer (NSCLC) treated with stereotactic body radiotherapy (SBRT) at the University of Pennsylvania between 2009 and 2013 was used to create predictive models of tumor control, normal tissue complications, and mortality in this IRB‐approved study. Nearly 200 data fields of detailed patient‐ and tumor‐specific information, radiotherapy dosimetric measurements, and clinical outcomes data were collected. Predictive models were created for local tumor control, 1‐ and 3‐year overall survival, and nodal failure using 60% of the data (leaving the remainder as a test set). After applying feature selection and dimensionality reduction, nonlinear support vector classification was applied to the resulting features. Models were evaluated for accuracy and area under ROC curve on the 81‐patient test set.Results:Models for common events in the dataset (such as mortality at one year) had the highest predictive power (AUC = .67, p &lt; 0.05). For rare occurrences such as radiation pneumonitis and local failure (each occurring in less than 10% of patients), too few events were present to create reliable models.Conclusion:Although this study demonstrates the validity of predictive analytics using information extracted from patient medical records and can most reliably predict for survival after SBRT, larger sample sizes are needed to develop predictive models for normal tissue toxicities and more advanced machine learning methodologies need be consider in the future.

SU‐E‐T‐591: Optimizing the Flattening Filter Free Beam Selection in RapidArc‐Based Stereotactic Body Radiotherapy for Stage I Lung Cancer

Purpose:To optimize the flattening filter free (FFF) beam energy selection in stereotactic body radiotherapy (SBRT) treatment for stage I lung cancer with different fraction schemes.Methods:Twelve patients suffering from stage I lung cancer were enrolled in this study. Plans were designed using 6XFFF and 10XFFF beams with the most widely used fraction schemes of 4*12 Gy, 3*18 Gy and 1*34 Gy, respectively. The plan quality was appraised in terms of planning target volume (PTV) coverage, conformity of the prescribed dose (CI100%), intermediate dose spillage (R50% and D2cm), organs at risk (OARs) sparing and beam‐on time.Results:The 10XFFF beam predicted 1% higher maximum, mean dose to the PTV and 4–5% higher R50% compared with the 6XFFF beam in the three fraction schemes, whereas the CI100% and D2cm was similar. Most importantly, the 6XFFF beam exhibited 3–10% lower dose to all the OARs. However, the 10XFFF beam reduced the beam‐on time by 31.9±7.2%, 38.7±2.8% and 43.6±4.0% compared with the 6XFFF beam in the 4*12 Gy, 3*18 Gy and 1*34 Gy schemes, respectively. Beam‐on time was 2.2±0.2 vs 1.5±0.1, 3.3±0.9 vs 2.0±0.5 and 6.3±0.9 vs 3.5±0.4 minutes for the 6XFFF and 10XFFF one in the three fraction schemes.Conclusion:The 6XFFF beam obtains better OARs sparing in SBRT treatment for stage I lung cancer, but the 10XFFF one provides improved treatment efficiency. To balance the OARs sparing and intrafractional variation as a function of prolonged treatment time, the authors recommend to use the 6XFFF beam in the 4*12 Gy and 3*18 Gy schemes for better OARs sparing. However, for the 1*34 Gy scheme, the 10XFFF beam is recommended to achieve improved treatment efficiency.

Stereotactic body radiotherapy for Stage I lung cancer with chronic obstructive pulmonary disease: special reference to survival and radiation-induced pneumonitis.

This retrospective study aimed to evaluate radiation-induced pneumonitis (RIP) and a related condition that we define in this report—prolonged minimal RIP (pmRIP)—after stereotactic body radiotherapy (SBRT) for Stage I primary lung cancer in patients with chronic obstructive pulmonary disease (COPD). We assessed 136 Stage I lung cancer patients with COPD who underwent SBRT. Airflow limitation on spirometry was classified into four Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades, with minor modifications: GOLD 1 (mild), GOLD 2 (moderate), GOLD 3 (severe) and GOLD 4 (very severe). On this basis, we defined two subgroups: COPD-free (COPD −) and COPD-positive (COPD +). There was no significant difference in overall survival or cause-specific–survival between these groups. Of the 136 patients, 44 (32%) had pmRIP. Multivariate analysis showed that COPD and the Brinkman index were statistically significant risk factors for the development of pmRIP. COPD and the Brinkman index were predictive factors for pmRIP, although our findings also indicate that SBRT can be tolerated in early lung cancer patients with COPD.

Stereotactic body radiation therapy for stage I non-small cell lung cancer: a small academic hospital experience.

Purpose/Objective(s): Stereotactic body radiation therapy (SBRT) has been shown to have increased local control and overall survival relative to conventional external beam radiation therapy in patients with medically inoperable stage I non-small cell lung cancer (NSCLC). Excellent rates of local control have been demonstrated both in clinical trials and in single-center studies at large academic institutions. However, there is limited data on the experiences of small academic hospitals with SBRT for stage I NSCLC. The purpose of this study is to report the local control and overall survival rates in patients treated with SBRT for stage I NSCLC at Winthrop-University Hospital (WUH), a small academic hospital.Materials/Methods: This is a retrospective review of 78 stage I central and peripheral NSCLC tumors treated between December 2006 and July 2012 with SBRT at WUH. Treatment was given utilizing fiducials and a respiratory tracking system. If the fiducials were not trackable, a spine tracking system was used for tumor localization. CT-based planning was performed using the ray trace algorithm. Treatment was delivered over consecutive days to a median dose of 4800 cGy delivered in four fractions. The Kaplan–Meier method was used to calculate local control and overall survival.Results: The median age was 78.5 years. Fifty-four percent of the patient population was female. Sixty seven percent of the tumors were stage IA, and 33% of the tumors were stage IB. Fifty-three percent of the tumors were adenocarcinomas and 29% were squamous cell carcinomas, with the remainder being of unknown histology or NSCLC, not otherwise specified The 2-year local control rate was 87%, and the 2-year overall survival was 68%.Conclusion: Our findings support that local control and overall survival at a small academic hospital are comparable to that of larger academic institutions’ published experiences with SBRT for stage I NSCLC.

Comparison of accelerated hypofractionation and stereotactic body radiotherapy for Stage 1 and node negative Stage 2 non-small cell lung cancer (NSCLC)

PurposeStereotactic body radiation therapy (SBRT) and accelerated hypofractionated radiation therapy (AHRT) have favorable local control (LC) relative to conventional fractionation in the treatment of stage I non-small cell lung cancer (NSCLC). We report the results of our single institution experience with the treatment of early stage NSCLC with SBRT or AHRT in cases where SBRT was felt to be suboptimal. MethodsOne hundred and sixty patients with Stage 1 and node negative Stage 2 NSCLC were treated with SBRT or AHRT from 2003 to 2011. Median follow-up was 29.4 and 19 months (mo), respectively. The median dose was 54Gy in 3 fractions (fx) (SBRT) and 70.2Gy in 26 fx (AHRT). Acute and late toxicities (tox) were graded (G) per CTCAE v4. Time to local (LF), regional (RF) and distant (DF) failure were estimated using the Kaplan–Meier method. The impact of patient and tumor related factors on LF were estimated by multivariate Cox proportional hazard model. ResultsThree-year LC rates were 87.7% (SBRT) and 71.7% (AHRT). The 3-year freedom from DF was 73.3% and 68.1%. Median OS was 38.4 (95% CI 29.7–51.6) and 35 (95% CI 22–48.3) mo. No G3 or 4 tox were observed. At 1 year, 30% and 50% of complications resolved, while (5–6%) had persistent chest wall pain.Multivariate analysis demonstrated that increasing dose per fraction and tumor size (>5.5 vs. 4cm) in the AHRT and SBRT group were found to be associated with a reduced (HR 0.33 95% CI 0.13–0.84, p=0.021) and increased (HR: 6.372 95% CI 1.23–32.92, p=0.027) hazard for local failure respectively. ConclusionsOur results compare favorably with other reports of treatment for early stage NSCLC. AHRT patients had comparable LC despite increased size and central disease. Toxicity was limited and overall survival, regional and distant recurrences were similar between groups.

Particle Therapy: A Suitable Alternative to Stereotactic Body Radiotherapy for stage I Non-Small-Cell Lung Cancer?

353 ISSN 1758-1966 10.2217/LMT.13.40 © 2013 Future Medicine Ltd Lung Cancer Manage. (2013) 2(5), 353–356 Many new particle therapy centers are now under construction all over the world. In Japan, ten centers (one center with a proton and carbon accelerator, two centers with a carbon accelerator and seven centers with a proton accelerator) are now in service, and four are now preparing for the start of clinical service or under construction as of July 2013. Nearly 20 years have passed since the National Institute for Radiological Sciences (NIRS) in Chiba (Japan), started carbon-ion therapy in 1994. Longterm results of particle therapy, including those on stage I non-small-cell lung cancer (NSCLC), are gradually accumulating. Recently, clinical results of particle therapy with a median follow-up of 51 months for patients with T2a/bN0M0 NSCLC have been published from the Hyogo Ion Beam Medical Center (HIBMC) in Japan; of the 70 patients reported, 43 were treated with proton beams and 27 received carbon-ion therapy [1]. These patients were not randomized, but both proton and carbonion therapy plans were made, and either modality that showed superior dose distribution was chosen for treatment. The 4-year overall survival rate was 58% and the 4-year local control rate was 75% (70% for T2a and 84% for T2b). Toxicities were acceptable, with only two cases of grade 3 pulmonary toxicity. There appeared to be no difference in outcome between proton and carbon-ion therapy. For T1 NSCLC, a 3-year overall survival rate of 74% and a 3-year local control rate of 87% were previously reported from the same institution [2]. Clinical outcomes reported from other proton therapy centers are in line with these results, although follow-up data are shorter [3–5]. Published clinical results from NIRS on carbon-ion therapy appear to show slightly higher local control rates, but the patient number is relatively small and follow-up is relatively short [6,7]. On the other hand, the role of stereotactic body radiotherapy (SBRT) using photons has been established for patients with stage I NSCLC who are medically inoperable or refuse surgery. The reported results of SBRT generally indicate local control rates of 80–90% for T1 tumors and 65–80% for T2 tumors at 3–5 years [8–10]. The 5-year overall survival rates are 65–75% for operable patients and 35–50% for medically inoperable patients. The best

Safety and Efficacy of Stereotactic Body Radiotherapy for Stage I Non–Small-Cell Lung Cancer in Routine Clinical Practice: A Patterns-of-Care and Outcome Analysis

To evaluate safety and efficacy of stereotactic body radiotherapy (SBRT) for stage I non-small-cell lung cancer (NSCLC) in a patterns-of-care and patterns-of-outcome analysis. The working group "Extracranial Stereotactic Radiotherapy" of the German Society for Radiation Oncology performed a retrospective multicenter analysis of practice and outcome after SBRT for stage I NSCLC. Sixteen German and Austrian centers with experience in pulmonary SBRT were asked to participate. Data of 582 patients treated at 13 institutions between 1998 and 2011 were collected; all institutions, except one, were academic hospitals. A time trend to more advanced radiotherapy technologies and escalated irradiation doses was observed, but patient characteristics (age, performance status, pulmonary function) remained stable over time. Interinstitutional variability was substantial in all treatment characteristics but not in patient characteristics. After an average follow-up of 21 months, 3-year freedom from local progression (FFLP) and overall survival (OS) were 79.6% and 47.1%, respectively. The biological effective dose was the most significant factor influencing FFLP and OS: after more than 106 Gy biological effective dose as planning target volume encompassing dose (N = 164), 3-year FFLP and OS were 92.5% and 62.2%, respectively. No evidence of a learning curve or improvement of results with larger SBRT experience and implementation of new radiotherapy technologies was observed. SBRT for stage I NSCLC was safe and effective in this multi-institutional, academic environment, despite considerable interinstitutional variability and time trends in SBRT practice. Radiotherapy dose was identified as a major treatment factor influencing local tumor control and OS.

Stereotactic Body Radiation Therapy for Stage I Non-small-cell Lung Cancer: A Historical Overview of Clinical Studies

Because of difficulties with stabilization, breathing motion and dosimetry, stereotactic body radiotherapy for lung cancer has only been practiced for the past 15 years. However, a large amount of case data has rapidly been accumulated in recent years. Stereotactic body radiotherapy for Stage I non-small-cell lung cancer has been actively investigated in inoperable patients since around 1995, and a number of clinical trials have been undertaken. Early studies from 2001 presented a 3-year local control rate of 94% and a 3-year overall survival rate of 66% for patients receiving 50-60 Gy in 10 fractions. Another study in 2005, using 48 Gy in four fractions, presented a 3-year local control rate of 98% and 3-year overall survival rates of 83% for Stage IA patients and 72% for Stage IB patients. A multi-institutional study showed favorable local control and survival rates in a group receiving a biologically effective dose of 100 Gy. A dose-escalation study in the USA suggested a maximum tolerated dose of 60 Gy in three fractions. A Phase II clinical trial (RTOG0236) followed, with a reported 3-year local control rate of 98% and a 3-year overall survival rate of 56% for patients who received 60 Gy in three fractions. A Japanese Phase II clinical trial (JCOG0403) investigated a dose of 48 Gy in four fractions among 165 Stage IA patients, showing a 3-year survival rate of 76% and a 3-year locally progression-free survival rate of 69% for the operable group. An overview of past clinical trials in stereotactic body radiotherapy for Stage I non-small-cell lung cancer and current issues is presented and discussed.

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.

Intensity-modulated stereotactic body radiotherapy for stage I non-small cell lung cancer

This study aimed to investigate the clinical outcomes of intensity-modulated radiotherapy (IMRT)-based stereotactic body radiotherapy (SBRT) for patients with stage I non-small cell lung cancer (NSCLC). A prospective database of 16 consecutive patients receiving SBRT for pathologically-proven and peripherally-located stage I NSCLC was reviewed. Fifteen patients were medically inoperable and one patient refused to undergo surgery. The median age of the patients was 76 years (range, 69–86). Treatment planning used four-dimensional computed tomography and fixed-field IMRT (n=11) or volumetric-modulated arc therapy (VMAT; n=5). The SBRT scheme was 48 Gy in four fractions (n=9) or 55 Gy in five fractions (n=7), delivered on consecutive days. The overall response rate at 6 months was 78.6%, including a complete response in three (21.4%) patients and a partial response in eight (57.1%). Three patients (21.4%) demonstrated a stable disease status. The median follow-up time was 14 months (range, 6–20) for the surviving patients. One patient developed local failure at 11 months, while another suffered from regional failure in a subcarinal lymph node at 4 months. Two patients did not survive within the first 6 months; one patient died during salvage chemotherapy for mediastinal lymph node metastasis and the other succumbed to a cause unrelated to lung cancer. The Kaplan-Meier estimates of local failure-free, progression-free and overall survival rates at 18 months were 91.0, 85.2 and 87.5%, respectively. The toxicity was mild; no severe (grade ≥3) toxicity was identified. IMRT-based (including VMAT) delivery of SBRT for patients with stage I NSCLC demonstrated favorable responses and local control without severe toxicity.

Clinical results of stereotactic body radiotherapy for Stage I small-cell lung cancer: a single institutional experience

The purpose of this study was to evaluate the treatment outcomes of stereotactic body radiotherapy (SBRT) for Stage I small-cell lung cancer (SCLC). From April 2003 to September 2009, a total of eight patients with Stage I SCLC were treated with SBRT in our institution. In all patients, the lung tumors were proven as SCLC pathologically. The patients' ages were 58–84 years (median: 74). The T-stage of the primary tumor was T1a in two, T1b in two and T2a in four patients. Six of the patients were inoperable because of poor cardiac and/or pulmonary function, and two patients refused surgery. SBRT was given using 7–8 non-coplanar beams with 48 Gy in four fractions. Six of the eight patients received 3–4 cycles of chemotherapy using carboplatin (CBDCA) + etoposide (VP-16) or cisplatin (CDDP) + irinotecan (CPT-11). The follow-up period for all patients was 6–60 months (median: 32). Six patients were still alive without any recurrence. One patient died from this disease and one died from another disease. The overall and disease-specific survival rate at three years was 72% and 86%, respectively. There were no patients with local progression of the lesion targeted by SBRT. Only one patient had nodal recurrence in the mediastinum at 12 months after treatment. The progression-free survival rate was 71%. No Grade 2 or higher SBRT-related toxicities were observed. SBRT plus chemotherapy could be an alternative to surgery with chemotherapy for inoperable patients with Stage I small-cell lung cancer. However, further investigation is needed using a large series of patients.

Lung-cancer related chest events detected by periodical follow-up CT after stereotactic body radiotherapy for stage I primary lung cancer: retrospective analysis of incidence of lung-cancer related chest events and outcomes of salvage treatment

Follow-up by chest CT is often performed routinely after stereotactic body radiotherapy (SBRT) for primary lung cancer. We investigated how often periodical chest CT detected lung-cancer related chest events (failure in the chest, new primary lung cancer), and how often chest CT follow-ups led to curative intent salvage treatment. Between 2006 and 2009, 90 stage I primary lung cancers in 86 patients received SBRT. In principle, chest CT was scheduled every 2-3 months in the first two years, and every 3-4 months thereafter. Median time to follow-up by chest CT was 26 months (1-61 months). Twenty-seven lung-cancer related chest events were detected by periodical chest CT after SBRT. The three-year lung-cancer related chest event free rate was 62 %. It was possible to apply curative-intent salvage treatment to 56 % of the lung-cancer related chest events. The two-year overall survival rate was 66 % among the 13 patients who received curative-intent salvage treatment (radiotherapy, 11; surgery, 2). Post-SBRT lung-cancer related chest events (as detected by periodical chest CT) were not uncommon (approximately 40 % at 3 years from SBRT), and it was possible to treat more than half of these lesions with curative-intent salvage treatment.

Proton SBRT for Medically Inoperable Stage I NSCLC

The physical properties of proton beam radiation may offer advantages for treating patients with non-small-cell lung cancer (NSCLC). However, its utility for the treatment of medically inoperable stage I NSCLC patients with stereotactic body radiation therapy (SBRT) is unknown. Outcomes for patients with medically inoperable stage I NSCLC treated with proton SBRT were retrospectively analyzed. Proton SBRT was selected as the treatment modality based on pulmonary comorbidities (n = 5), prior chest radiation or/and multiple primary tumors (n = 7), or other reasons (n = 3). Treatments were administered using 2 to 3 proton beams. Treatment toxicity was scored according to common toxicity criteria for adverse events version 4 criteria. Fifteen consecutive patients and 20 tumors were treated with proton SBRT to 42 to 50 Gy(relative biological effectiveness) in 3 to 5 fractions between July 2008 and September 2010. Treatments were well tolerated with only one case of grade 2 fatigue, one case of grade 2 dermatitis, three cases of rib fracture (maximum grade 2), and one case of grade 3 pneumonitis in a patient with severe chronic obstructive pulmonary disease. With a median follow-up of 24.1 months, 2-year overall survival and local control rates were 64% (95% confidence limits, 34%-83%) and 100% (83%-100%), respectively. We conclude that proton SBRT is effective and well tolerated in this unfavorable group of patients. Prospective clinical trials testing the utility of proton SBRT in stage I NSCLC are warranted.

Predicting the risk of secondary malignancies associated with stereotactic body radiation therapy.

e17562 Background: Treatment of early-stage non-small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT) is associated with high rates of local control and long-term overall survival. With increasing frequency, SBRT is a treatment option for operable tumors which raises the question of the risk of long-term toxicities such as radiation-induced secondary malignancies. There has been no previous risk assessment or epidemiological studies of secondary malignancies with high-dose hypofractionated SBRT. In this study, we seek to quantify the predicted rates of secondary lung malignancies in patients treated with SBRT for stage I-II NSCLC. Methods: Treatment plans for 14 stage I-II NSCLC patients treated with definitive-intent SBRT at Columbia University Medical Center were retrospectively assessed. Median patient age was 73 years (range 54 - 86) with median tumor size of 2.8 cm (range 1.2 - 5.0). SBRT doses ranged from 40-60 Gy in 3-5 fractions. Dose-volume histograms for target PTV and normal lung were generated from planning CT scans. A biologically-based mathematical model of spontaneous and radiation-induced carcinogenesis was used to determine the excess absolute risk and the median lifetime estimated relative risk of secondary lung malignancies for each plan. These risks were then compared using 2-sided t-tests. Results: For all patients, the median lifetime estimated absolute risk of secondary lung malignancy was 1.06% (95% CI 0.62%-1.98%), and the median lifetime estimated relative risk of secondary lung malignancy was 1.61 (95% CI 1.47-1.75) after SBRT. For patients aged less than 65 years, median estimated absolute risk of secondary malignancies was higher (2.8%) than for patients age 65 and older (0.37%), p &lt; 0.001. PTV volume less than 50 cc vs greater than 50 cc, T1 vs T2 tumors, and gender were not significantly associated with differences in estimated absolute risk or estimated relative risk of secondary malignancies. Conclusions: As SBRT is potentially indicated in younger medically operable patients, the long-term late toxicities need to be determined. This study suggests that the risk of second lung malignancies from high-dose SBRT even in younger patients would be minimal.

Stereotactic body radiotherapy for stage I non–small cell lung cancer

Surgical resection for patients with stage I non-small cell lung cancer (NSCLC) produces high long-term survival rates, but many patients are ineligible for surgery because of medical comorbidity or other factors. Stereotactic body radiotherapy (SBRT) is the standard of care for patients with medically inoperable stage I NSCLC. Studies have reported local control rates with SBRT of about 95% when an adequate radiation dose is used. Lymph node failure averages less than 5%, while distant metastatic recurrence represents the most common site of failure. SBRT is generally safe and well tolerated even by patients with substantial pulmonary comorbidities. On average, lung function tests reveal little or no change from baseline, although individual patients may exhibit changes in pulmonary function after treatment. Most studies report pneumonitis rates of 0% to 5%. Ongoing clinical trials are investigating single-fraction SBRT and evaluating the maximal tolerated dose for centrally located tumors.

I期非小細胞肺癌に対する定位放射線治療の臨床研究のレビュー

I期非小細胞肺癌に対する定位放射線治療の臨床研究のレビュー

Outcome Analysis of Sublobar Resection and Intraoperative 125I Brachytherapy vs. Stereotactic Body Radiotherapy in Stage I Non-small Cell Lung Carcinoma

To compare patterns of failure and survival of high-risk Stage I non small cell lung cancer (NSCLC) patients treated using either sublobar resection (SLR) and 125I lung brachytherapy or stereotactic body radiotherapy (SBRT).

Stereotactic Body Radiotherapy for Stage I Non-small Cell Lung Cancer Causes Immune Suppression

Stereotactic Body Radiotherapy for Stage I Non-small Cell Lung Cancer Causes Immune Suppression

Histology Predicts Changes in Standard Uptake Value (SUV) and Radiographic Response After Stereotactic Body Radiotherapy (SBRT) in Stage I Non-small Cell Lung Cancer

To evaluate the correlation among positron emission tomography (PET) SUV maximum values, CT volumetric response, and tumor histology in patients treated with SBRT for Stage I non-small cell lung cancer (NSCLC). Medical records of 68 consecutive patients with 75 Stage I NSCLC lesions were analyzed after SBRT. All patients had PET/CT scans prior to SBRT. Patients had a post treatment CT scan at 6 weeks and a PET/CT at 3 months. Alternating CT and PET scans were obtained every 3 months thereafter. Pre and post treatment CT volumes and PET SUV maximum values were measured. Patients received 45-54 Gy in 3-5 fractions, given twice a week. Treatments were prescribed to an isodose line ranging from 75%-95%. The median overall survival was 41 months, with a median follow-up of 10 months. Local control for this cohort was 97% with 2 patients failing at the original site of disease. In both cases, tumors were treated to 45 Gy in 5 fractions. When pre- and post-treatment gross tumor CT volumes were compared, adenocarcinoma histology had less relative volumetric reduction than squamous tumors (95% CI: 22-97%, p < 0.001) at 1.5 and 3 months, indicating a faster radiologic response for squamous cell carcinoma. Similarly, when pre- and post-treatment PET maximum SUV were compared, adenocarcinoma had a smaller relative decrease in maximum uptake at 3 months than squamous histology (p-value < 0.0001). We further explored the relationship between the response by CT volume and by PET maximum SUV. Although a correlation was observed, it did not reach statistical significance. Squamous histology responded faster by both relative CT volume and PET maximum SUV value after SBRT. Additional patient data is needed to correlate PET SUV response to CT volume reduction after SBRT.