Stereotactic ablative radiotherapy for small lung tumors with a moderate dose: Favorable results and low toxicity

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

PURPOSE

Numerous dose and fractionation schedules have been used to treat medically inoperable stage I non-small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy. We evaluated published experiences with SBRT to determine local control (LC) rates as a function of SBRT dose.

METHODS AND MATERIALS

One hundred sixty published articles reporting LC rates after SBRT for stage I NSCLC were identified. Quality of the series was assessed by evaluating the number of patients in the study, homogeneity of the dose regimen, length of follow-up time, and reporting of LC. Clinical data including 1, 2, 3, and 5-year tumor control probabilities for stages T1, T2, and combined T1 and T2 as a function of the biological effective dose were fitted to the linear quadratic, universal survival curve, and regrowth models.

RESULTS

Forty-six studies met inclusion criteria. As measured by the goodness of fit χ2/ndf, with ndf as the number of degrees of freedom, none of the models were ideal fits for the data. Of the 3 models, the regrowth model provides the best fit to the clinical data. For the regrowth model, the fitting yielded an α-to-β ratio of approximately 25 Gy for T1 tumors, 19 Gy for T2 tumors, and 21 Gy for T1 and T2 combined. To achieve the maximal LC rate, the predicted physical dose schemes when prescribed at the periphery of the planning target volume are 43 ± 1 Gy in 3 fractions, 47 ± 1 Gy in 4 fractions, and 50 ± 1 Gy in 5 fractions for combined T1 and T2 tumors.

CONCLUSIONS

Early-stage NSCLC is radioresponsive when treated with SBRT or stereotactic ablative radiation therapy. A steep dose-response relationship exists with high rates of durable LC when physical doses of 43-50 Gy are delivered in 3 to 5 fractions.

Dose coverage impacts local control in ultra-central lung oligometastases treated with stereotactic radiotherapy

INTRODUCTION

The use of Stereotactic Body Radiotherapy (SBRT) is controversial in Ultra-Central lung tumors, a subset of central lung tumors characterized by proximity to critical mediastinal structures. This is of interest in oligometastatic (≤3 metastases) patients, who can yield survival benefit from local treatments. The aim of our study is to assess the determinants of efficacy and toxicity in this setting.

MATERIALS AND METHODS

Clinical and dosimetric parameters were reviewed in a cohort of oligometastatic patients treated with SBRT for ultra-central tumors. Local control rate (LC) and toxicity were assessed. Statistical Analysis was carried out to assess the impact of those predictors on local recurrence and adverse events.

RESULTS

One-hundred-nine consecutive patients were included. A median Biologic Effective Dose (BED) of 105 (75-132) Gy10 was prescribed. At a median follow-up of 17 (range 3-78) months, 2-year LC was 87%. Improved LC was correlated to Planning Treatment Volume (PTV) covered by 95% of the prescription dose (V95% PTV) > 85% (HR 0.15, 95%CI 0.05-0.49, p = 0.0017) and to Gross Tumor Volume (GTV) < 90 cm³ (HR 0.2, 95%CI 0.07-0.56, p = 0.0021). Overall and grade ≥ 3 toxicity incidence was 20% and 5%, respectively. Patients experiencing acute and late toxicities received significantly higher dose to 1 cm³ (D1cm³) of esophagus and lung volume receiving ≥5 Gy (V5Gy) (p = 0.016 and p = 0.013), and higher dose to 0.1 cm³ (D0.1cm³) of heart (p = 0.036), respectively.

CONCLUSION

V95% PTV > 85% and GTV < 90 cm³ are independent predictors of LC. Dose to esophagus, lung and heart should be carefully assessed to minimize treatment-related toxicities.

Stereotactic Radiotherapy for Ultra-Central Lung Oligometastases in Non-Small-Cell Lung Cancer

Background: Stereotactic body radiotherapy (SBRT) in ultra-central (UC) lung tumors, defined in the presence of planning target volume (PTV) overlap or direct tumor abutment to the central bronchial tree or esophagus, may be correlated to a higher incidence of severe adverse events. Outcome and toxicity in oligometastatic (≤3 metastases) non-small-cell lung cancer (NSCLC) patients receiving SBRT for UC tumors were evaluated. Methods: Oligometastatic NSCLC patients treated with SBRT for UC were retrospectively reviewed. Local control (LC), distant metastasis-free survival (DMFS), progression-free survival (PFS) and overall survival (OS) were calculated. Incidence and grade of toxicity were evaluated. Statistical analysis was performed to assess the impact of clinical and treatment-related variables on outcome and toxicity occurrence. Results: Seventy-two patients were treated to a median biologically effective dose (BED) of 105 (75–132) Gy¹⁰. Two-year LC, DMFS, PFS, and OS were 83%, 46%, 43%, and 49%. BED>75 Gy¹⁰ was correlated to superior LC (p = 0.02), PFS (p = 0.036), and OS (p < 0.001). Grade ≥3 toxicity rate was 7%, including one fatal esophagitis. No variables were correlated to DMFS or to occurrence of overall and grade ≥3 toxicity. Conclusions: SBRT using dose-intensive schedules improves outcome in NSCLC patients. Overall toxicity is acceptable, although rare but potentially fatal toxicities may occur.

Outcomes and toxicity of stereotactic body radiation therapy for advanced stage ultra-central non-small cell lung cancer

BACKGROUND

Previous studies have documented a high incidence of toxicity in patients with ultra-central non-small cell lung cancer (UC-NSCLC) treated with stereotactic body radiation therapy (SBRT). However, these studies mainly focused on early stage patients and included small sample populations. We reviewed the outcomes and toxicity of SBRT in patients with advanced stage UC-NSCLC treated at our institution.

METHODS

Fifty-one consecutive patients with advanced UC-NSCLC treated with SBRT using a regular regimen of 35 Gy administered in five fractions between December 2014 and August 2017 were reviewed. UC was defined as tumors abutting or overlapping the trachea or the proximal bronchial tree. We included locally advanced patients who were unfit or unwilling to receive conventional chemoradiotherapy and patients with metastatic or postoperative recurrent disease. Clinical outcomes, dosimetric parameters, and SBRT toxicity were analyzed.

RESULTS

The median age was 63 years (range: 35-82), and the median tumor diameter was 6.8 cm (range: 2.1-12.4). The overall median follow-up duration was 17 months (25.5 months for surviving patients). The median local control was 17 months for stage III patients and 11 months for stage IV or recurrent patients. Grade 3 or higher toxicity was observed in 9.8% of patients: G3 radiation pneumonitis (5.9%) and possible treatment-related death (3.9%).

CONCLUSION

SBRT with a moderate dose in 4-6 fractions is effective and tolerable for patients with advanced stage UC-NSCLC. However, caution should be taken considering possible treatment-related death. Further studies are warranted.

Retrospective comparison of stereotactic body radiotherapy versus intensity-modulated radiotherapy for stage III ultra-central squamous non-small-cell lung cancer

Aim: To analyze the efficacy and toxicity of stereotactic body radiotherapy (SBRT) versus intensity-modulated radiotherapy (IMRT) in stage III patients with ultra-central squamous non-small-cell lung cancer (sqNSCLC). Methods: Forty-four stage III patients with ultra-central sqNSCLC receiving SBRT (n = 15) or IMRT (n = 29) between December 2014 and August 2017 were reviewed. Results: At a median follow-up of 16.5 months, the 1-year local control rate of SBRT and IMRT was 60.8 and 37.5%, respectively (p = 0.23); the median overall survival was 17 versus 18 months (p = 0.48); ≥3 grade toxicity was 20 versus 24.1% (p = 0.83). Conclusion: SBRT is effective and patient friendly for stage III patients with ultra-central sqNSCLC. Toxicity might be tolerable with a moderate dose five to six fraction regimen. However, more prospective studies are warranted.

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.

Management of Pulmonary Oligometastases by Stereotactic Body Radiotherapy

Aims and Background

The aim of the study was to evaluate the feasibility, toxicity and effectiveness of active breathing control-guided stereotactic body radiotherapy in the management of pulmonary oligometastases.

Methods and Study Design

Between June 2010 and June 2012, 20 patients (13 males, 7 females) with 31 pulmonary metastases referred to the Department of Radiation Oncology, Gulhane Military Medical Academy were treated using active breathing control-guided stereotactic body radiotherapy. Response Evaluation Criteria in Solid Tumors and Common Terminology Criteria for Adverse Events were used in the assessment of treatment response and toxicity, respectively.

Results

Assessment of treatment response revealed complete response, partial response, stable disease, and progressive disease in 30%, 25%, 30%, and 15% of the patients, respectively. At a median follow-up of 14 months, local control was 85% and overall survival was 70%, with negligible treatment-related toxicity.

Conclusions

Stereotactic body radiotherapy is safe and effective in the management of pulmonary oligometastases. It offers favorable treatment outcomes as a viable non-invasive therapeutic modality.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Clinical Outcomes of 130 Patients with Primary and Secondary Lung Tumors treated with Cyberknife Robotic Stereotactic Body Radiotherapy

Background

Authors report clinical outcomes of patients treated with robotic stereotactic body radiotherapy (SBRT) for primary, recurrent and metastatic lung lesions.

Patients and methods

130 patients with 160 lesions were treated with Cyberknife SBRT, including T1-3 primary lung cancers (54%), recurrent tumors (22%) and pulmonary metastases (24%). The mean biologically equivalent dose (BED_10Gy) was 151 Gy (72–180 Gy). Median prescribed dose for peripheral and central lesions was 3×20 Gy and 3×15 Gy, respectively. Local control (LC), overall survival (OS), and cause-specific survival (CSS) rates, early and late toxicities are reported. Statistical analysis was performed to identify factors influencing local tumor control.

Results

Median follow-up time was 21 months. In univariate analysis, higher dose was associated with better LC and a cut-off value was detected at BED_10Gy ≤ 112.5 Gy, resulting in 1-, 2-, and 3-year actuarial LC rates of 93%, vs 73%, 80% vs 61%, and 63% vs 54%, for the high and low dose groups, respectively (p = 0.0061, HR = 0.384). In multivariate analysis, metastatic origin, histological confirmation and larger Planning Target Volume (PTV) were associated with higher risk of local failure. Actuarial OS and CSS rates at 1, 2, and 3 years were 85%, 74% and 62%, and 93%, 89% and 80%, respectively. Acute and late toxicities ≥ Gr 3 were observed in 3 (2%) and 6 patients (5%), respectively.

Conclusions

Our favorable LC and survival rates after robotic SBRT, with low rates of severe toxicities, are coherent with the literature data in this mixed, non-selected study population.

Retrospective analysis of stereotactic ablative radiotherapy (SABR) for metastatic lung lesions (MLLs) in comparison with a contemporaneous cohort of primary lung lesions (PLLs)

BACKGROUND

The net benefit from local ablative therapy for pulmonary oligometastases remains unknown. The outcomes of stereotactic ablative radiotherapy (SABR) for metastatic lung lesions (MLLs) were analyzed retrospectively and compared with those of SABR for primary lung lesions (PLLs).

METHODS

Medical records of patients treated with lung SABR between 2011 and 2014 were retrospectively reviewed. Basic patient, lesion and treatment characteristics were compared using the Pearson chi-square test for categorical and Mann-Whitney U test for continuous variables. To estimate the rates of local control (LC), progression-free survival (PFS), survival after the first progression post-SABR (SAPF) and overall survival (OS), the Kaplan-Meier method was used, and the differences between groups were assessed by means of the log rank test. The uni- and multivariate Cox proportional hazards regression model was used to identify predictive factors for these endpoints.

RESULTS

Twenty-nine MLLs in 18 consecutive patients and 51 PLLs in 42 patients were treated stereotactically and included in the study. Median follow-up was 14 months (range, 4-40 months). Although patients with MLLs had a significantly better cardiopulmonary function (P=0.0001), more conservative dose-fractionation schedules were prescribed (P=0.0001), but this did not result in a significant difference in LC (P=0.98), PFS (P=0.06) and OS (P=0.14). Multivariate analysis revealed that the dose per fraction (≥ or <12 Gy) was an independent predictor for LC (P=0.02) and PFS (P=0.01) for the whole population, and for PFS (P=0.02) in the PLLs group. Late toxicities ≥ G2 occurred in six patients with PLLs, compared with none in the metastatic group.

CONCLUSIONS

SABR for MLLs was as successful as for PLLs with respect to LC and OS with lower long-term toxicity in patients with MLLs. Dose per fraction ≥12 Gy turned out to be an independent, favorable prognostic factor.

Tumor control probability modeling for stereotactic body radiation therapy of early-stage lung cancer using multiple bio-physical models

This work is to analyze pooled clinical data using different radiobiological models and to understand the relationship between biologically effective dose (BED) and tumor control probability (TCP) for stereotactic body radiotherapy (SBRT) of early-stage non-small cell lung cancer (NSCLC). The clinical data of 1-, 2-, 3-, and 5-year actuarial or Kaplan-Meier TCP from 46 selected studies were collected for SBRT of NSCLC in the literature. The TCP data were separated for Stage T1 and T2 tumors if possible, otherwise collected for combined stages. BED was calculated at isocenters using six radiobiological models. For each model, the independent model parameters were determined from a fit to the TCP data using the least chi-square (χ²) method with either one set of parameters regardless of tumor stages or two sets for T1 and T2 tumors separately. The fits to the clinic data yield consistent results of large α/β ratios of about 20Gy for all models investigated. The regrowth model that accounts for the tumor repopulation and heterogeneity leads to a better fit to the data, compared to other 5 models where the fits were indistinguishable between the models. The models based on the fitting parameters predict that the T2 tumors require about additional 1Gy physical dose at isocenters per fraction (⩽5 fractions) to achieve the optimal TCP when compared to the T1 tumors. In conclusion, this systematic analysis of a large set of published clinical data using different radiobiological models shows that local TCP for SBRT of early-stage NSCLC has strong dependence on BED with large α/β ratios of about 20Gy. The six models predict that a BED (calculated with α/β of 20) of 90Gy is sufficient to achieve TCP⩾95%. Among the models considered, the regrowth model leads to a better fit to the clinical data.

Simple Factors Associated With Radiation-Induced Lung Toxicity After Stereotactic Body Radiation Therapy of the Thorax: A Pooled Analysis of 88 Studies

PURPOSE

To study the risk factors for radiation-induced lung toxicity (RILT) after stereotactic body radiation therapy (SBRT) of the thorax.

METHODS AND MATERIALS

Published studies on lung toxicity in patients with early-stage non-small cell lung cancer (NSCLC) or metastatic lung tumors treated with SBRT were pooled and analyzed. The primary endpoint was RILT, including pneumonitis and fibrosis. Data of RILT and risk factors were extracted from each study, and rates of grade 2 to 5 (G2+) and grade 3 to 5 (G3+) RILT were computed. Patient, tumor, and dosimetric factors were analyzed for their correlation with RILT.

RESULTS

Eighty-eight studies (7752 patients) that reported RILT incidence were eligible. The pooled rates of G2+ and G3+ RILT from all 88 studies were 9.1% (95% confidence interval [CI]: 7.15-11.4) and 1.8% (95% CI: 1.3-2.5), respectively. The median of median tumor sizes was 2.3 (range, 1.4-4.1) cm. Among the factors analyzed, older patient age (P=.044) and larger tumor size (the greatest diameter) were significantly correlated with higher rates of G2+ (P=.049) and G3+ RILT (P=.001). Patients with stage IA versus stage IB NSCLC had significantly lower risks of G2+ RILT (8.3% vs 17.1%, odds ratio = 0.43, 95% CI: 0.29-0.64, P<.0001). Among studies that provided detailed dosimetric data, the pooled analysis demonstrated a significantly higher mean lung dose (MLD) (P=.027) and V20 (P=.019) in patients with G2+ RILT than in those with grade 0 to 1 RILT.

CONCLUSIONS

The overall rate of RILT is relatively low after thoracic SBRT. Older age and larger tumor size are significant adverse risk factors for RILT. Lung dosimetry, specifically lung V20 and MLD, also significantly affect RILT risk.

Oesophagus side effects related to the treatment of oesophageal cancer or radiotherapy of other thoracic malignancies

The oesophagus as a serial organ located in the central chest is frequent subject to "incidental" dose application in radiotherapy for several thoracic malignancies including oesophageal cancer itself. Especially due to the radiosensitive mucosa severe radiotherapy induced sequelae can occur, acute oesophagitis and strictures as late toxicity being the most frequent side-effects. In this review we focus on oesophageal side effects derived from treatment of gastrointestinal cancer and secondly provide an overview on oesophageal toxicity from conventional and stereotactic fractionated radiotherapy to the thoracic area in general. Available data on pathogenesis, frequency, onset, and severity of oesophageal side effects are summarized. Whereas for conventional radiotherapy the associations of applied doses to certain volumes of the oesophagus are well described, the tolerance dose to the mediastinal structures for hypofractionated therapy is unknown. The review provides available attempts to predict the risk of oesophageal side effects from dosimetric parameters of SBRT.

Hypofractionated radiotherapy for medically inoperable stage I non-small cell lung cancer

BACKGROUND

To investigate the clinical outcomes and toxicity of hypofractionated radiotherapy for medically inoperable stage I non-small cell lung cancer (NSCLC).

METHODS

Patients treated with radiotherapy at a dose of 4-6 Gy per fraction using fixed-field intensity modulated radiotherapy (IMRT) or volumetric-modulated arc therapy (VMAT) at our hospital from June 2005 to December 2013 were analyzed. The total prescription doses ranged from 50-78 Gy with 4-6 Gy per fraction. The median follow-up period was 24 months.

RESULTS

A total of 65 patients with stage I NSCLC were analyzed, including 43 primary NSCLC patients and 22 patients with recurrent or second primary NSCLC. An objective response (complete or partial response) was achieved at six months in 84.6% of patients. The three-year local control rate was 90.8%. Kaplan-Meier estimates of local failure-free, progression-free, overall, and cancer-specific survival rates at three years were 90.3%, 64.3%, 68.9%, and 88.8%, respectively. The rate of symptomatic radiation pneumonitis was 16.9%, and no grade 4-5 toxicity was observed.

CONCLUSION

Favorable local control and outcome was achieved with hypofractionated radiotherapy in patients with inoperable stage I NSCLC with acceptable toxicity. The most common schedule of 6 Gy × 12 fractions may be a promising regimen, and a prospective study is in process.

LungTech, an EORTC Phase II trial of stereotactic body radiotherapy for centrally located lung tumours: a clinical perspective

Evidence supports stereotactic body radiotherapy (SBRT) as a curative treatment option for inoperable early stage non-small-cell lung cancer (NSCLC) resulting in high rates of tumour control and low risk of toxicity. However, promising results are mainly derived from SBRT of peripheral pulmonary lesions, whereas SBRT for the central tumours can lead to severe radiation sequelae owing to the spatial proximity to the serial organs at risk. Robust data on the tolerance of mediastinal structures to high-dose hypofractionated radiation are limited; furthermore, there are many open questions regarding the efficiency, safety and response assessment of SBRT in inoperable, centrally located early stage NSCLC, which are addressed in a prospective multicentre study [sponsored by the European Organization for Research and Treatment of Cancer (EORTC 22113-08113-LungTech)]. In this review, we summarize the current status regarding SBRT for centrally located early stage NSCLC that leads to the rationale of the LungTech trial. Outline and some essential features of the study with focus on a summary of current experiences in dose/fraction-toxicity coherences after SBRT to the mediastinal structures that lead to LungTech normal tissue constraints are provided.

Visualization of data in radiotherapy using web services for optimization of workflow

BACKGROUND

Every day a large amount of data is produced within a radiotherapy department. Although this data is available in one form or other within the centralised systems, it is often not in the form which is of interest to the departmental staff. This work presents a flexible browser based reporting and visualization system for clinical and scientific use, not currently found in commercially available software such as MOSAIQ(TM) or ARIA(TM). Moreover, the majority of user merely wish to retrieve data and not record and/or modify data. Thus the idea was conceived, to present the user with all relevant information in a simple and effective manner in the form of web-services. Due to the widespread availability of the internet, most people can master the use of a web-browser. Ultimately the aim is to optimize clinical procedures, enhance transparency and improve revenue.

METHODS

Our working group (BAS) examined many internal procedures, to find out whether relevant information suitable for our purposes lay therein. After the results were collated, it was necessary to select an effective software platform. After a more detailed analysis of all data, it became clear that the implementation of web-services was appropriate. In our institute several such web-based information services had already been developed over the last few years, with which we gained invaluable experience. Moreover, we strived for high acceptance amongst staff members.

RESULTS

By employing web-services, we attained high effectiveness, transparency and efficient information processing for the user. Furthermore, we achieved an almost maintenance-free and low support system. The aim of the project, making web-based information available to the user from the departmental system MOSAIQ, physician letter system MEDATEC(R) and the central finding server MiraPlus (laboratory, pathology and radiology) were implemented without restrictions.

CONCLUSION

Due to widespread use of web-based technology the training effort was effectively nil, since practically every member of staff can master the use of a web-browser. Moreover, we have achieved high acceptance amongst staff members and have improved our effectiveness resulting in a considerable time saving. The many MOSAIQ-specific parts of the system can be readily used by departments which use MOSAIQ as the departmental system.

DART-bid: dose-differentiated accelerated radiation therapy, 1.8 Gy twice daily: high local control in early stage (I/II) non-small-cell lung cancer

BACKGROUND

While surgery is considered standard of care for early stage (I/II), non-small-cell lung cancer (NSCLC), radiotherapy is a widely accepted alternative for medically unfit patients or those who refuse surgery. International guidelines recommend several treatment options, comprising stereotactic body radiation therapy (SBRT) for small tumors, conventional radiotherapy ≥ 60 Gy for larger sized especially centrally located lesions or continuous hyperfractionated accelerated RT (CHART). This study presents clinical outcome and toxicity for patients treated with a dose-differentiated accelerated schedule using 1.8 Gy bid (DART-bid).

PATIENTS AND METHODS

Between April 2002 and December 2010, 54 patients (median age 71 years, median Karnofsky performance score 70%) were treated for early stage NSCLC. Total doses were applied according to tumor diameter: 73.8 Gy for <  2.5 cm, 79.2 Gy for 2.5-4.5 cm, 84.6 Gy for 4.5-6 cm, 90 Gy for > 6 cm.

RESULTS

The median follow-up was 28.5 months (range 2-108 months); actuarial local control (LC) at 2 and 3 years was 88%, while regional control was 100%. There were 10 patients (19%) who died of the tumor, and 18 patients (33%) died due to cardiovascular or pulmonary causes. A total of 11 patients (20%) died intercurrently without evidence of progression or treatment-related toxicity at the last follow-up, while 15 patients (28%) are alive. Acute esophagitis ≤ grade 2 occurred in 7 cases, 2 patients developed grade 2 chronic pulmonary fibrosis.

CONCLUSION

DART-bid yields high LC without significant toxicity. For centrally located and/or large (> 5 cm) early stage tumors, where SBRT is not feasible, this method might serve as radiotherapeutic alternative to present treatment recommendations, with the need of confirmation in larger cohorts.

Stereotactic body radiotherapy for centrally located stage I NSCLC: a multicenter analysis

PURPOSE

The purpose of this work is to analyze patterns of care and outcome after stereotactic body radiotherapy (SBRT) for centrally located, early-stage, non-small cell lung cancer (NSCLC) and to address the question of potential risk for increased toxicity in this entity.

METHODS AND MATERIALS

A total of 90 patients with centrally located NSCLC were identified among 613 cases in a database of 13 German and Austrian academic radiotherapy centers. The outcome of centrally located NSCLC was compared to that of cases with peripheral tumor location from the same database.

RESULTS

Patients with central tumors most commonly presented with UICC stage IB (50 %), while the majority of peripheral lesions were stage IA (56 %). Average tumor diameters were 3.3 cm (central) and 2.8 cm (peripheral). Staging PET/CT was available for 73 and 74 % of peripheral and central tumors, respectively. Biopsy was performed in 84 % (peripheral) and 88 % (central) of cases. Doses varied significantly between central and peripheral lesions with a median BED10 of 72 Gy and 84 Gy, respectively (p < 0.001). Fractionation differed as well with medians of 5 (central) and 3 (peripheral) fractions (p < 0.001). In the Kaplan-Meier analysis, 3-year actuarial overall survival was 29 % (central) and 51 % (peripheral; p = 0.004) and freedom from local progression was 52 % (central) and 84 % (peripheral; p < 0.001). Toxicity after treatment of central tumors was low with no grade III/IV and one grade V event. Mortality rates were 0 and 1 % after 30 and 60 days, respectively.

CONCLUSION

Local tumor control in patients treated with SBRT for centrally located, early-stage NSCLC was favorable, provided ablative radiation doses were prescribed. This was, however, not the case in the majority of patients, possibly due to concerns about treatment-related toxicity. Reported toxicity was low, but prospective trials are needed to resolve the existing uncertainties and to establish safe high-dose regimens for this cohort of patients.

Primary non-small cell lung cancer in a transplanted lung treated with stereotactic body radiation therapy. A case study

The first case of primary lung cancer in a transplanted lung was described in 2001. Since then, only 5 cases of lung cancer in donated lung have been reported. We present one more patient with non-small cell cancer in the transplanted lung treated with stereotactic body radiation therapy. In most cases of primary lung cancer in transplanted lung, rapid progression of the cancer was reported. Occurrence of the locoregional failure in our case could be explained by factors related to the treatment protocol and also to underlying immunosuppression.

Clinical outcome of hypofractionated breath-hold image-guided SABR of primary lung tumors and lung metastases

Background

Stereotactic Ablative RadioTherapy (SABR) of lung tumors/metastases has been shown to be an effective treatment modality with low toxicity. Outcome and toxicity were retrospectively evaluated in a unique single-institution cohort treated with intensity-modulated image-guided breath-hold SABR (igSABR) without external immobilization. The dose–response relationship is analyzed based on Biologically Equivalent Dose (BED).

Patients and methods

50 lesions in 43 patients with primary NSCLC (n = 27) or lung-metastases of various primaries (n = 16) were consecutively treated with igSABR with Active-Breathing-Coordinator (ABC®) and repeat-breath-hold cone-beam-CT. After an initial dose-finding/-escalation period, 5x12 Gy for peripheral lesions and single doses of 5 Gy to varying dose levels for central lesions were applied. Overall-survival (OS), progression-free-survival (PFS), progression pattern, local control (LC) and toxicity were analyzed.

Results

The median BED2 was 83 Gy. 12 lesions were treated with a BED2 of <80 Gy, and 38 lesions with a BED2 of >80 Gy. Median follow-up was 15 months. Actuarial 1- and 2-year OS were 67% and 43%; respectively. Cause of death was non-disease-related in 27%. Actuarial 1- and 2-year PFS was 42% and 28%. Progression site was predominantly distant. Actuarial 1- and 2 year LC was 90% and 85%. LC showed a trend for a correlation to BED2 (p = 0.1167). Pneumonitis requiring conservative treatment occurred in 23%.

Conclusion

Intensity-modulated breath-hold igSABR results in high LC-rates and low toxicity in this unfavorable patient cohort with inoperable lung tumors or metastases. A BED2 of <80 Gy was associated with reduced local control.