Stereotactic radiotherapy of histologically proven inoperable stage I non-small cell lung cancer: patterns of failure

Histology-driven hypofractionated radiation therapy schemes for early-stage lung adenocarcinoma and squamous cell carcinoma

BACKGROUND AND PURPOSE

Histology was found to be an important prognostic factor for local tumor control probability (TCP) after stereotactic body radiotherapy (SBRT) of early-stage non-small-cell lung cancer (NSCLC). A histology-driven SBRT approach has not been explored in routine clinical practice and histology-dependent fractionation schemes remain unknown. Here, we analyzed pooled histologic TCP data as a function of biologically effective dose (BED) to determine histology-driven fractionation schemes for SBRT and hypofractionated radiotherapy of two predominant early-stage NSCLC histologic subtypes adenocarcinoma (ADC) and squamous cell carcinoma (SCC).

MATERIAL AND METHODS

The least-χ2 method was used to fit the collected histologic TCP data of 8510 early-stage NSCLC patients to determine parameters for a well-developed radiobiological model per the Hypofractionated Treatment Effects in the Clinic (HyTEC) initiative.

RESULTS

A fit to the histologic TCP data yielded independent radiobiological parameter sets for radiotherapy of early-stage lung ADC and SCC. TCP increases steeply with BED and reaches an asymptotic maximal plateau, allowing us to determine model-independent optimal fractionation schemes of least doses in 1-30 fractions to achieve maximal tumor control for early-stage lung ADC and SCC, e.g., 30, 44, 48, and 51 Gy for ADC, and 32, 48, 54, and 58 Gy for SCC in 1, 3, 4, and 5 fractions, respectively.

CONCLUSION

We presented the first determination of histology-dependent radiobiological parameters and model-independent histology-driven optimal SBRT and hypofractionated radiation therapy schemes for early-stage lung ADC and SCC. SCC requires substantially higher radiation doses to maximize tumor control than ADC, plausibly attributed to tumor genetic diversity and microenvironment. The determined optimal SBRT schemes agree well with clinical practice for early-stage lung ADC. These proposed optimal fractionation schemes provide first insights for histology-based personalized radiotherapy of two predominant early-stage NSCLC subtypes ADC and SCC, which require further validation with large-scale histologic TCP data.

[Impact of immunotherapy on the therapeutic strategy for the management of stage I non-small cell lung cancer: The radiation oncologist's point of view]

Surgery is the standard treatment for operable patients with stage I non-small cell lung cancer (NSCLC) (T1-T2aN0M0). Stereotactic body radiotherapy (SBRT) is the treatment of choice for non-operable patients, and its positioning for operable patients remains to be clarified. The pattern of recurrence after management of stage I NSCLC is dominated by the risk of distant recurrence, this constituting the rationale for the adjunction of systemic treatment, and especially check point inhibitor (CPI), in combination with surgery or SBRT for patients with high risk features. While the benefit of postoperative CPI on the micro-metastatic disease is logically considered within the framework of a simply additive effect of both therapeutic modalities, it is reasonable to consider a synergistic effect of both CPI and SBRT. Given the role of tumor draining nodes in the development of an anti-tumor immune response, a "tumor-draining node sparing" strategy enabled by SBRT could therefore be of major interest in combination with CPI. Pending confirmation of the role of CPI in combination with RTS for the management of stage I NSCLC, we thus discuss in this review the theoretical advantages that this therapeutic strategy could have compared to a surgical strategy.

Cost-effectiveness of stereotactic body radiotherapy versus conventional fractionated radiotherapy for medically inoperable, early-stage non-small cell lung cancer

BACKGROUND

Stereotactic body radiotherapy (SBRT) is a novel radio-therapeutic technique that has recently emerged as standard-of-care treatment for medically inoperable, early-stage non-small cell lung cancer (NSCLC). In this study, we compared the cost-effectiveness of SBRT with that of conventional fractionated radiotherapy (CFRT) in patients with medically inoperable, early-stage NSCLC from the perspective of the Chinese health system.

METHODS

A Markov model was developed to describe health states of patients after treatment with SBRT and CFRT. The recurrence risks, treatment toxicities, and utilities inputs were obtained from the literature. The costs were based on listed prices and real-world evidence. A simulation was conducted to determine the post-treatment lifetime years. For each treatment, the total costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) per QALY were calculated. Deterministic and probabilistic sensitivity analyses were performed to assess the uncertainty of the model parameters.

RESULTS

In the base case analysis, SBRT was associated with a mean cost of USD16,933 and 2.05 QALYs, whereas CFRT was associated with a mean cost of USD17,726 and 1.61 QALYs. SBRT is a more cost-effective strategy compared with CFRT for medically inoperable, early-stage NSCLC, with USD 1802 is saved for every incremental QALY. This result was validated by DSA and PSA, in which SBRT remained the most cost-effective option.

CONCLUSIONS

The findings suggested that, compared to CFRT, SBRT may be considered a more cost-effective strategy for medically inoperable, early-stage NSCLC.

Harmonization of dose prescription for lung stereotactic radiotherapy

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Doses standardization achieved between dedicated linac and robotic-assisted unit.

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Both methods delivered 3×18.3 Gy to the near minimum dose of the tumor volume.

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Four-Dimensional deformable method allowed to estimate dose to a mobile tumor.

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The reliability of a double-check software using a Monte-Carlo algorithm was validated.

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Gross Tumor Volume-based prescription presented less dose heterogeneities to the tumor.

Background and purpose

Pulmonary stereotactic treatments can be performed using dedicated linear accelerators as well as robotic-assisted units, and different strategies can be used for dose prescription. This study aimed to compare the doses received by the tumor with a gross tumor volume (GTV)-based prescription on D_98%GTV using a robotic-assisted unit (method A) and planning target volume (PTV)-based prescription on D_95%PTV using a dedicated linac (method B).

Material & methods

Plans of 32 patients were collected for method A, and a dose of 3 × 18 Gy was prescribed using type A algorithm and recalculated using a Monte-Carlo (MC) algorithm. The plans were normalized to match D_98%GTV with the mean D98%GTV¯ of the cohort. The plans of 23 patients were collected for method B, and a dose of 3 × 18 Gy was prescribed to D_95%PTV using a MC algorithm. A 4D-sum method was developed to estimate doses for PTV and GTV. For validation, all plans were recalculated using an independent MC double-check software. A dose harmonization on D_{98% GTV} was determined for both methods.

Results

For method A, mean doses were D_2%GTV = 59.9 ± 2.1 Gy, D_50%GTV = 55.6 ± 1.2 Gy, D_98%GTV = 49.5 ± 0.0 Gy. For method B, the reported doses were D_2%GTV = 64.6 ± 2.1 Gy, D_50%GTV = 62.8 ± 1.7 Gy, and D_98%GTV = 60.0 ± 1.7 Gy. The dose trade-off of D_98%GTV = 55 Gy was obtained for both methods. For method A, it corresponded to a dose prescription of 3 × 20 Gy using type A algorithm, followed by rescaling to obtain D_98%GTV = 55 Gy. For method B, it corresponded to a dose prescription of D_95%PTV = 3 × 16.5 Gy using the MC algorithm.

Conclusions

This study determined similar near-minimum doses D_{98% GTV} of approximately 3 × 18.3 Gy (55 Gy) using a GTV-based prescription on a robotic-assisted unit (method A) and a PTV-based prescription on a dedicated linac (method B).

Rationale for Combing Stereotactic Body Radiation Therapy with Immune Checkpoint Inhibitors in Medically Inoperable Early-Stage Non-Small Cell Lung Cancer

Simple Summary

The rate of recurrence remains high for lymph node negative early-stage non-small cell lung cancer that are over 2–3 cm in size following stereotactic body radiation therapy (SBRT). This is due to the increased incidence of out-of-field failures, which warrants the addition of systemic therapy. Immune checkpoint inhibitors (ICIs), a class of immunotherapy, may induce a strong distant therapeutic effect known as the “abscopal” effect. This makes them a very suitable class of drugs to be combined with SBRT when treating early lung cancer with high-risk features, such as larger tumor size. In this review, we discuss the rationale and evidence for doing so.

Abstract

Stereotactic body radiation therapy (SBRT) has been widely adopted as an alternative to lobar resection in medically inoperable patients with lymph-node negative (N0) early-stage (ES) non-small cell lung cancer (NSCLC). Excellent in-field local control has been consistently achieved with SBRT in ES NSCLC ≤ 3 cm in size. However, the out-of-field control following SBRT remains suboptimal. The rate of recurrence, especially distant recurrence remains high for larger tumors. Additional systemic therapy is warranted in N0 ES NSCLC that is larger in size. Radiation has been shown to have immunomodulatory effects on cancer, which is most prominent with higher fractional doses. Strong synergistic effects are observed when immune checkpoint inhibitors (ICIs) are combined with radiation doses in SBRT’s dose range. Unlike chemotherapy, ICIs can potentiate a strong systemic response outside of the irradiated field when combined with SBRT. Together with their less toxic nature, ICIs represent a very suitable class of systemic agents to be combined with SBRT when treating ES NSCLC with high-risk features, such as larger tumor size. In this review, we describe the rationale and emerging evidence, as well as ongoing investigations in this area.

Inoperable Early-Stage Non-Small-Cell Lung Cancer: Stereotactic Ablative Radiotherapy and Rationale for Systemic Therapy

Stereotactic ablative radiotherapy (SABR) is the standard treatment for medically inoperable, early-stage non-small-cell lung cancer. SABR results in high rates of in-field tumor control, but among larger and more biologically aggressive tumors, regional and distant failures are problematic. Cytotoxic chemotherapy is rarely used in this patient population and the benefit is unclear. Alternative systemic therapy options with a milder side-effect profile are of considerable interest, and several randomized phase III trials are currently testing immune checkpoint inhibitors in this setting. We review the rationale, data, and ongoing studies evaluating systemic therapy in medically inoperable, early-stage non-small-cell lung cancer treated with SABR.

Discontinuous stereotactic body radiotherapy schedule increases overall survival in early-stage non-small cell lung cancer

OBJECTIVES

The duration of stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC) may affect patient outcomes. We aimed to determine the impact of a continuous versus discontinuous SBRT schedule on local control (LC) and overall survival (OS) in NSCLC patients.

MATERIALS AND METHODS

Consecutive NSCLC stage I patients (475) treated with SBRT in four centers were retrospectively analyzed. The delivered dose ranged from 48 to 75 Gy in 3-10 fractions. Based on the ratio between the treatment duration (TD) and number of fractions (n), patients were divided into two groups: continuous schedule (CS) (TD ≤ 1.6n; 239 patients) and discontinuous schedule (DS) (TD > 1.6n; 236 patients). LC and OS were compared using Cox regression analyses after propensity score matching (216 pairs).

RESULTS

The median follow-up period was 41 months. Multivariate analysis showed that the DS (hazard ratio (HR): 0.42; 95 % confidence interval (CI): 0.22-0.78) and number of fractions (HR: 1.24; 95 % CI: 1.07-1.43) were significantly associated with LC. The DS (HR: 0.67; 95 % CI: 0.51-0.89), age (HR: 1.02; 95 % CI: 1-1.03), WHO performance status (HR: 2.27; 95 % CI: 1.39-3.7), and T stage (HR: 1.4; 95 % CI: 1.03-1.87) were significantly associated with OS. The 3-year LC and OS were 92 % and 64 % and 81 % and 53 % for DS and CS treatments, respectively (p < 0.01). Cox analysis confirmed that the discontinuous SBRT schedule significantly increased LC and OS.

CONCLUSION

DS is associated with significantly improved LC and OS in early-stage NSCLC patients treated with SBRT.

In-field stereotactic body radiotherapy (SBRT) reirradiation for pulmonary malignancies as a multicentre analysis of the German Society of Radiation Oncology (DEGRO)

Data of thoracic in-field reirradiation with two courses of stereotactic body radiotherapy (SBRT) is scarce. Aim of this study is to investigate feasibility and safety of this approach. Patients with a second course of thoracic SBRT and planning target volume (PTV) overlap were analyzed in this retrospective, multicenter study. All plans and clinical data were centrally collected. 27 patients from 8 centers have been amenable for evaluation: 12 with non-small-cell lung cancer, 16 with metastases, treated from 2009 (oldest first course) to 2020 (latest second course). A median dose of 38.5 Gy to the 65%-isodose over a median of 5 fractions was prescribed in the first course and 40 Gy in 5 fractions for the second SBRT-course. Median PTV of the second SBRT was 29.5 cm³, median PTV overlap 22 cm³. With a median interval of 20.2 months between the two SBRT-courses, 1-year OS, and -LCR were 78.3% and 70.3% respectively. 3 patients developed grade 1 and one grade 2 pneumonitis. No grade > 2 toxicity was observed. Peripheral location and dose were the only factors correlating with tumor control. A second SBRT-course with PTV overlap appears safe and achieves reasonable local control.

Improved Survival Outcomes in Medically Fit Patients With Early-Stage Non-Small-Cell Lung Cancer Undergoing Stereotactic Body Radiotherapy

INTRODUCTION

Stereotactic body radiotherapy (SBRT) has been shown to result in excellent disease control rates for early-stage non-small-cell lung cancer (NSCLC). It remains unknown which patients would most benefit from SBRT in treating NSCLC.

PATIENTS AND METHODS

We conducted a retrospective analysis of 346 patients treated with SBRT for early-stage NSCLC at 2 institutions (86 patients from City of Hope National Medical Center and 260 patients from The Newport Beach Radiosurgery Center/Hoag Hospital) from February 2010 to July 2019. The primary endpoint was overall survival (OS). The omnibus test of model coefficients was performed to study the associations between clinical factors and OS. Survival analyses were performed by the log-rank test and Cox proportional hazards regression.

RESULTS

Under the univariate analysis, variables associated with a decreased likelihood of death included age < 65 years (P = .040) and being a surgical candidate (P = .010). Multivariate analysis found that surgical candidates still had a significantly decreased likelihood of death compared to nonsurgical candidates (Hazard ratio 0.360, 95% confidence interval 0.153-0.848, P = .019). Median OS was significantly increased for surgical candidates versus nonsurgical candidates (83 vs 53 months, P = .017). The local failure rate was 9.1%, the locoregional failure rate was 12.7%, and the distant failure rate was 10.7%.

CONCLUSION

Patients who are deemed to be candidates for surgery have improved OS compared to those who are not when treated with SBRT. This raises the question of selection bias in trials comparing surgery with SBRT in NSCLC, as patients who are deemed to be surgical candidates and then go on to undergo surgery may have an inherent OS benefit.

Developing and validating an integrated gross tumor volume (GTV)-TNM stratification system for supplementing unresectable locally advanced non-small cell lung cancer treated with concurrent chemoradiotherapy

Purpose

The gross tumor volume (GTV) could be an independent prognostic factor for unresectable locally advanced non-small cell lung cancer (LANSCLC). We aimed to develop and validate a novel integrated GTV-TNM stratification system to supplement LANSCLC sub-staging in patients treated with concurrent chemoradiotherapy (CCRT).

Methods

We performed a retrospective review of 340 patients with unresectable LANSCLC receiving definitive CCRT. All included patients were divided into two randomized cohorts. Then the Kaplan–Meier method and Cox regression were calculated to access the prognostic value of the integrated GTV-TNM stratification system, which was further validated by the area under the receiver operating characteristic curve (AUC) score and F1-score.

Results

The optimal outcome-based GTV cut-off values (70 and 180 cm³) of the modeling cohort were used to determine each patient’s integrated GTV-TNM stratum in the whole cohort. Our results indicated that a lower integrated GTV-TNM stratum could had better overall survival and progression-free survival (all P < 0.001), which was recognized as an independent prognostic factor. Also, its prognostic value was robust in both the modeling and validation cohorts. Furthermore, the prognostic validity of the integrated GTV-TNM stratification system was validated by significantly improved AUC score (0.636 vs. 0.570, P = 0.027) and F1-score (0.655 vs. 0.615, P < 0.001), compared with TNM stage.

Conclusions

We proposed a novel integrated GTV-TNM stratification system to supplement unresectable LANSCLC sub-staging due to its prognostic value independent of TNM stage and other clinical characteristics, suggesting that it could be considered in individual treatment decision-making process.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Generalized Multi-Hit Model of Radiation-Induced Cell Survival with a Closed-Form Solution: An Alternative Method for Determining Isoeffect Doses in Practical Radiotherapy

The standard linear-quadratic (LQ) model is currently the preferred model for describing the ionizing radiation-induced cell survival curves and tissue responses. And the LQ model is also widely used to calculate isoeffect doses for comparing different fractionated schemes in clinical radiotherapy. Despite its ubiquity, because the actual dose-response curve may appear linear at high doses in the semilogarithmic plot, the application of the LQ model is greatly challenged in the high-dose region, while the dose employed in stereotactic body radiotherapy (SBRT) is often in this area. Alternatively, the biophysical models of radiation-induced effects with a linear-quadratic-linear (LQL) characteristic can well fit the dose-survival curve of cells in vitro. However, most of these LQL models are phenomenological and have not fully considered the biophysical mechanism of radiation-induced damage and repair, and the fitting quality decreases in some high-dose ranges. In this work, to provide an alternative model to describe the cell survival curves in high-dose ranges and predict the biologically effective dose (BED) for SBRT, we propose a novel generalized multi-hit model with a closed-form solution by considering an upper bound on the number of lethal damages induced by radiation that can be repaired in a cell. This model has a clear biophysical basis and a simple expression, and also has the LQL characteristic under low- and high-dose approximate conditions. The experimental data fitting indicated that compared to the standard LQ model and our previously generalized target model, the current model can better fit the radiation-induced cell survival curves in the high-dose ranges (P < 0.05). The current model parameters and parameter ratios were determined from the fits in different kinds of cell lines irradiated with various dose rates and linear energy transfer (LET), which indicates that the model parameters significantly depend on the dose rate and LET. Based on the current model, we derived two equivalence formulae for the BED calculations in the low- and high-dose ranges, and then calculated the BED for the clinical data of SBRT from 17 selected studies. The correlation analysis showed that there were significant linear correlations between the BED at isocenter and planning target volume (PTV) edge calculated by this model and the LQ model (R > 0.86, P < 0.001). In conclusion, the generalized multi-hit model proposed in this work can be used as an alternative tool to handle in vitro radiation-induced cell survival curves in high-dose ranges, and calculate the in vivo BED for comparing the dose fractionation schemes in clinical radiotherapy.

Repeat stereotactic body radiation therapy (SBRT) for salvage of isolated local recurrence after definitive lung SBRT

PURPOSE

Optimal management of isolated local recurrences after stereotactic body radiation therapy (SBRT) for early non-small cell lung cancer (NSCLC) is unknown and literature describing repeat SBRT for in-field recurrences after initial SBRT are sparse. We investigate the safety and efficacy of salvage SBRT for isolated local failures after initial SBRT for NSCLC.

METHODS/MATERIALS

Patients receiving SBRT for isolated local recurrence after initial SBRT for early NSCLC were identified using a prospective registry. Both courses were 3-5 fractions with a biologically effective dose (BED10) of ≥100 Gy. Local failure was defined as within 1 cm of the initial planning target volume (PTV) or an overlap of the ≥25% isodose lines of the first and second treatments. Failures >1 cm beyond the PTV and without ≥25% overlap, or with additional recurrence sites were excluded. Kaplan-Meier analysis was used to estimate survival.

RESULTS

A total 21 patients receiving salvage SBRT from 2008 to 2017 were identified. Median interval from initial SBRT to salvage SBRT was 23 months (7-52). Six patients (29%) had central tumors. Median follow-up time from salvage SBRT was 24 months (3-60). Median overall survival after salvage was 39 months. After reirradiation, two-year primary tumor control was 81%, regional nodal control was 89%, distant control was 75% and overall survival was 68%. Grade 2 pneumonitis occurred in 2 patients (10%) and grade 2 chest wall toxicity in 4 patients (19%). No grade 3+ toxicity was observed.

CONCLUSIONS

Salvage SBRT for isolated local failures after initial SBRT appears safe, with low treatment-related toxicity and encouraging rates of tumor control.

Prognostic Role Of Computed Tomography Textural Features In Early-Stage Non-Small Cell Lung Cancer Patients Receiving Stereotactic Body Radiotherapy

Purpose

The imaging features of patients with early-stage non-small cell lung cancer (NSCLC) receiving stereotactic body radiotherapy (SBRT) are crucial for the decision-making process to establish a treatment plan. The purpose of this study was to predict the clinical outcomes of SBRT from the textural features of pretreatment computed tomography (CT) images.

Patients and methods

Forty-one early-stage NSCLC patients who received SBRT were included in this retrospective study. In total, 72 textural features were extracted from the pretreatment contrast-enhanced CT images. Survival analysis was used to identify high-risk groups for progression-free survival (PFS) and disease-specific survival (DSS). Receiver operating characteristic (ROC) curve analysis was utilized to estimate the diagnostic abilities of the textural parameters. Univariable and multivariable Cox regression analyses were performed to evaluate the predictors of PFS and DSS.

Results

Four parameters, including entropy (P=0.003), second angular moment (SAM) (P=0.04), high-intensity long-run emphasis (HILRE) (P=0.046) and long-run emphasis (LRE) (P=0.042), were significant prognostic features for PFS. In addition, contrast (P=0.008), coarseness (P=0.017), low-intensity zone emphasis (LIZE) (P=0.01) and large number emphasis (LNE) (P=0.046) were significant prognostic factors for DSS. In the ROC analysis, the area under the curve (AUC) of coarseness for local recurrence (LR) was 0.722 (0.528–0.916), and the AUC of entropy for lymph node metastasis (LNM) was 0.771 (0.556–0.987). The four highest AUCs for distant metastasis (DM) were 0.885 (0.784–0.985) for LNE, 0.846 (0.733–0.959) for SAM, 0.731 (0.500–0.961) for LRE and 0.731 (0.585–0.876) for contrast. In the multivariable analysis, smoking and entropy were independent prognostic factors for PFS.

Conclusion

This exploratory study reveals that textual features derived from pretreatment CT scans have prognostic value in early-stage NSCLC patients treated with SBRT.

Hypofractionated carbon-ion radiotherapy for stage I peripheral nonsmall cell lung cancer (GUNMA0701): Prospective phase II study

This phase II study's aim was to confirm the efficacy and safety of hypofractionated carbon-ion radiotherapy in patients with stage I peripheral nonsmall cell lung cancer (NSCLC). The study encompassed 37 patients with histologically proven peripheral stage I NSCLC in the period June 2010-March 2015. All underwent the planned full dose of carbon-ion radiotherapy, administered with relative biological effectiveness of 52.8 Gy and 60 Gy (divided into four fractions over 1 week) for T1 and T2a tumors, respectively. The 2-year local control rate was set as the primary endpoint, while overall survival, progression-free survival, and the incidence rates of acute and late adverse events were secondary endpoints. The patients were followed up for 56.3 months overall and 62.2 months in the surviving patients, respectively. The actuarial local control rates were 91.2% after 2 years, and 88.1% after 5 years. No differences were found between the T1 and T2a tumors in the 5-year local control rate (90.9% vs 86.7%, P = .75). The actuarial overall survival rates achieved 91.9% for 2-year and 74.9% for 5-year period. T1 tumors showed actuarial 5-year overall survival rates of 80%, compared to 66.7% in T2a tumors. Two patients with T2a tumors and either severe emphysema or bronchiectasis experienced lung toxicity ≥ grade 2, in contrast to T1 patients who only experienced mild toxicities (lower than grade 2). The findings suggest that carbon-ion radiotherapy is effective and safe for peripheral stage I NSCLC; however, further clinical evaluations are needed to confirm its therapeutic efficacy. Trial registration: UMIN000003797. Registered 21 June 2010, prospectively registered.

[Stereotactic radiotherapy of stage I non-small cell lung cancer. State of the art in 2019 and recommendations: Stereotaxy as an alternative to surgery?]

Stereotactic radiotherapy (or Stereotactic body radiotherapy [SBRT]) is a technique currently well established in the therapeutic arsenal for the management of bronchial cancers. It represents the standard treatment for inoperable patients or who refuses surgery. It is well tolerated, especially in elderly and frail patients, and the current issue is to define its indications in operated patients, based on retrospective and randomized trials comparing stereotactic radiotherapy and surgery, with results equivalents. This work analyzes in detail the different aspects of pulmonary stereotactic radiotherapy and suggests arguments that help in the therapeutic choice between surgery and stereotaxic irradiation. In all cases, the therapeutic decision must be discussed in a multidisciplinary consultation meeting, while informing the patient of the possible therapeutic options.

Carbon-ion Radiotherapy for Isolated Lymph Node Metastasis After Surgery or Radiotherapy for Lung Cancer

Purpose: Mediastinal and hilar lymph node metastasis is one of the recurrence patterns after definitive treatment of lung cancer. Salvage radiotherapy (RT) can be a treatment option for lymph node metastasis. However, the usefulness of additional RT remains unclear after surgery or RT for the primary lung tumor. We retrospectively evaluated the efficacy and safety of hypofractionated carbon-ion RT for isolated lymph node metastasis. Methods and Materials: Between April 2013 and August 2016, 15 consecutive patients with isolated lymph node metastasis underwent carbon-ion RT. The pretreatment evaluations confirmed the isolated lymph node metastasis and the absence of local recurrence or distant metastasis, which was oligometastatic disease. The median age was 72 (range, 51-83) years, with 11 male patients. The first treatments for primary lung tumors were carbon-ion RT for 8 patients and surgery for 7 patients. There were 9 adenocarcinomas, 4 squamous cell carcinomas, 1 adenosquamous cell carcinoma, and 1 mucoepidermoid carcinoma. Most patients (93%) were irradiated with 52.8 Gy relative biological effectiveness in 12 fractions for 3 weeks. There were no patients treated with concurrent or adjuvant therapy such as chemotherapy, molecular-targeted therapy, or immunotherapy. Adverse events were evaluated according to the Common Terminology Criteria for Adverse Events (version 4.0). Results: The median follow-up for surviving patients was 28 months. One patient experienced local lymph node recurrence, and the 2-year local control rate was 92% for all patients. Distant metastasis was observed in 7 patients, and 2-year progression-free survival rate was 47%. During follow-up, there were 4 deaths from lung cancer, and the 2-year overall survival rate was 75%. There were 2 patients with acute grade 2 esophagitis and 2 with late grade 2 cough, which were improved by conservative therapy. There were no other grade 2 or higher adverse events. Conclusions: Hypofractionated carbon-ion RT showed excellent local control and overall survival without severe toxicities in lung cancer patients with isolated lymph node metastasis after surgery or carbon-ion RT for primary lung tumors. A multi-institutional prospective study is required to establish the efficacy and safety of carbon-ion RT.

Survival After Stereotactic Body Radiation Therapy for Clinically Diagnosed or Biopsy-Proven Early-Stage NSCLC: A Systematic Review and Meta-Analysis

INTRODUCTION

Stereotactic body radiation therapy (SBRT) is a promising curative treatment for early-stage NSCLC. It is unclear if survival outcomes for SBRT are influenced by a lack of pathological confirmation of malignancy and staging of disease in these patients. In this systematic review and meta-analysis, we assess survival outcomes after SBRT in studies with patients with clinically diagnosed versus biopsy-proven early-stage NSCLC.

METHODS

The main databases were searched for trials and cohort studies without restrictions to publication status or language. Two independent researchers performed the screening and selection of eligible studies. Outcomes were overall survival, cancer-specific survival, and disease-free survival. The inverse variance method and the random effects method for meta-analysis were used to assess pooled survival estimates.

RESULTS

A total of 11,195 nonduplicate records were identified by the original search strategy. After screening by title and abstract, 1051 potentially eligible records were identified. A total of 43 articles were included. The comparative studies showed lower 3-year overall survival and lower 2-year and 5-year cancer-specific survival for biopsy-proven disease compared to clinical disease. However, 5-year overall survival was the same for both groups. For the pooled estimates, 3-year disease-free survival and 2-year cancer-specific survival were lower for biopsied disease.

CONCLUSIONS

Results of this systematic review and meta-analysis show a discrepancy in oncological outcomes for patients undergoing SBRT for suspected early-stage NSCLC in whom there is pathologic conformation of malignancy and those who there is only a clinical diagnose of NSCLC. These results emphasize the importance of obtaining pathologic proof of malignancy.

Stereotactic body radiotherapy for lung tumors: Dosimetric analysis and clinical outcome

INTRODUCTION

Stereotactic body radiotherapy (SBRT) has emerged as an important modality in malignant lung tumor treatment both in early localized primary and oligometastatic setting. This study aims to present the results of lung SBRT both in terms of dosimetry and clinical outcome.

MATERIALS AND METHODS

Twenty-seven patients were assessed from 2012 to 2016. Both the primary and oligometastatic lung tumors were evaluated. Respiratory motion management was done employing ANZAI (Siemens, Germany) based four-dimensional computed tomography (CT). Commonly used fractionations were 60 Gy/5 fractions for peripheral tumors and 48 Gy/6 fractions for central tumors. Radiation Therapy Oncology Group toxicity criteria were used for toxicity and whole-body positron emission tomography-CT scan was done at follow-up for response evaluation.

RESULTS

Twenty-seven patients were evaluated, 18 (66.7%) patients had a primary, and 9 (33.3%) patients had metastatic lung tumors. The male-to-female ratio for the entire cohort was 2:1. The median age at diagnosis was 65.8 years. Mean planning target volume (PTV) D2cc was 54.9 ± 9.04 Gy and mean internal target volume diameter was 3.0 ± 1.07 cm. Mean V20 Gy, V10 Gy, and V5 Gy of (lungs total-PTV) and (Lung ipsilateral - PTV) were 5.4 ± 4% and 10.9 ± 7.9%, 11.7 ± 5.8% and 24.2 ± 14.0%, and 22.05 ± 12.4% and 33.2 ± 15.3%, respectively. In total 21 (84%) patients and 4 patients (16%) showed a complete and partial response, respectively. One (3%) patient developed Gr 3 radiation pneumonitis. One year local control was in 18 (81%) patients whereas 4 (14%) patients progressed and three patients did not report. A higher prescribed dose significantly correlated with 1 year tumor control (P = 0.036).

CONCLUSION

This study infers the feasibility and a favorable outcome for lung cancer amenable to SBRT in addition to being one of the largest clinical experiences for lung stereotactic treatment in our country.

A matched-pair analysis of stereotactic body radiotherapy (SBRT) for oligometastatic lung tumors from colorectal cancer versus early stage non-small cell lung cancer

BACKGROUND

The use of stereotactic body radiotherapy (SBRT) for early-stage primary non-small cell lung cancer (NSCLC) reported excellent local control rates. But the optimal SBRT dose for oligometastatic lung tumors (OLTs) from colorectal cancer (CRC) has not yet been determined. This study aimed to evaluate whether SBRT to a dose of 48-60 Gy in 4-5 fractions could result in similar local outcomes for OLTs from CRC as compared to early-stage NSCLC, and to examine potential dose-response relationships for OLTs from CRC.

METHODS

OLTs from CRC and primary NSCLCs treated with SBRT to 48-60 Gy in 4-5 fractions at a single institution were evaluated, and a matched-pair analysis was performed. Local recurrence-free survival (LRFS) was estimated by the Kaplan-Meier method. Univariate Cox regression was performed to identify significant predictors.

RESULTS

There were 72 lung lesions in 61 patients (24 OLTs from CRC in 15 patients and 48 NSCLCs in 46 patients) were analyzed with a median follow-up of 30 months. LRFS for OLTs from CRC was significantly worse than that of NSCLC when treated with 48-60 Gy/4-5 fx (p = 0.006). The 1, 3 and 5-year LRFS of OLTs from CRC vs NSCLC were 80.6% vs. 100%, 68.6% vs. 97.2%, and 68.6% vs. 81.0%, respectively. On univariate analysis, OLTs from CRC treated with higher dose (BED₁₀ = 132 Gy) exhibited significantly better local recurrence-free survival than those treated to lower doses (BED₁₀ ≤ 105.6 Gy) (p = 0.0022). The 1 and 3-year LRFS rates for OLTs treated to a higher dose (BED₁₀ = 132 Gy) were 88.9% and 81.5%, vs 33.3%, and not achieved for lower doses (BED₁₀ ≤ 105.6 Gy).

CONCLUSION

The LRFS of OLTs from CRC after SBRT of 48-60 Gy/4-5 fx was significantly worse than that of primary NSCLC. Lower dose SBRT appeared to have inferior control for OLTs of CRC in this cohort. Further studies with larger sample sizes are needed.

Early stage lung cancer survival after wedge resection and stereotactic body radiation

BACKGROUND

The comparative effectiveness of stereotactic body radiation therapy (SBRT) and wedge resection in the treatment of early stage lung cancer is still under debate. This meta-analysis compares the 5-year overall survival (OS) of wedge resection and SBRT in patients with stage I non-small cell lung cancer (NSCLC).

METHODS

Original research articles published between 1995 and 2017 were identified through the National Library of Medicine and National Institutes of Health PubMed database and through the reference lists of reviewed articles. Data were processed and analyzed in R (version 3.4.2) and a summary estimate that accounted for the sample size of each study was calculated. The combined percent survival was calculated using random effect models. Funnel plots were used to assess publication bias. Heterogeneity was tested using the Q statistic and the I2 statistic.

RESULTS

There were 16 studies totaling 1,984 patients with stage I NSCLC treated with wedge resection. The meta-estimate was 74% (95% CI, 66-81%), with significant heterogeneity across studies (Q =172.46, P<0.0001; I2=91.30%). Thirty-six studies including 3,309 patients with stage I NSCLC treated with SBRT/SABR produced a meta-estimate of 44% (95% CI, 38-50%), with significant heterogeneity (Q =423.55, P<0.0001; I2=91.74%). Two articles directly comparing stage I NSCLC patients treated with wedge resection to patients treated with SBRT both reported higher 5-year OS after wedge resection.

CONCLUSIONS

SBRT is a treatment option reserved to medically inoperable patients, but could be an alternative to surgery in medically operable patients who prefer a less invasive treatment. More standardized methods for data collection and reporting are necessary to allow better comparisons across published studies.

Stereotactic body radiotherapy for centrally-located lung tumors with 56 Gy in seven fractions: A retrospective study

Stereotactic body radiotherapy (SBRT) for centrally-located lung tumors remains a challenge because of the increased risk of treatment-related adverse events (AEs), and uncertainty around prescribing the optimal dose. The present study reported the results of central tumor SBRT with 56 Gy in 7 fractions (fr) at the University of Tokyo Hospital. A total of 35 cases that underwent SBRT with or without volumetric-modulated arc therapy consisting of 56 Gy/7 fr for central lung lesions between 2010 and 2016 at the University of Tokyo Hospital were reveiwed. A central lesion was defined as a tumor within 2 cm of the proximal bronchial tree (RTOG 0236 definition) or within 2 cm in all directions of any critical mediastinal structure. Local control (LC), overall survival (OS), and AEs were investigated. The Kaplan-Meier method was used to estimate LC and OS. AEs were scored per the Common Terminology Criteria for Adverse Events Version 4.0. Thirty-five patients with 36 central lung lesions were included. Fifteen lesions were primary non-small cell lung cancer (NSCLC), 13 were recurrences of NSCLC, and 8 had oligo-recurrences from other primaries. Median tumor diameter was 29 mm. Eighteen patients had had prior surgery. At a median follow-up of 13.1 months for all patients and 18.3 months in surviving patients, 22 patients had died, ten due to primary disease (4 NSCLC), while three were treatment-related. The 1- and 2-year OS were 57.3 and 40.4%, respectively, and median OS was 15.7 months. Local recurrence occurred in only two lesions. 1- and 2-year LC rates were both 96%. Nine patients experienced grade ≥3 toxicity, representing 26% of the cohort. Two of these were grade 5, one pneumonitis and one hemoptysis. Considering the background of the subject, tumor control of our central SBRT is promising, especially in primary NSCLC. However, the safety of SBRT to central lung cancer remains controversial.

Comparison of Single- and Three-fraction Schedules of Stereotactic Body Radiation Therapy for Peripheral Early-stage Non-Small-cell Lung Cancer

BACKGROUND

To compare the clinical outcomes of patients with early-stage non-small-cell lung cancer (NSCLC) who had undergone either single-fraction (SF) or three-fraction (TF) stereotactic body radiation therapy (SBRT) at a single institution during over 8-year period.

PATIENTS AND METHODS

Patients with peripherally located early-stage NSCLC who had undergone SBRT from February 2007 to November 2015 were included in the present study. SBRT was delivered without heterogeneity correction. Data were retrospectively reviewed and collected in an institutional review board-approved database. R software (version 3.3.2) was used for statistical analysis.

RESULTS

Of 159 total lung tumors, 65 lesions received 30 Gy (median, 30 Gy) in 1 fraction, and 94 lesions received 48 to 60 Gy (median, 60 Gy) in 3 fractions. Patients with a Karnofsky performance status < 80 were more common in the SF-SBRT cohort (P = .050). After a median follow-up of 22.2 and 26.2 months for the SF-SBRT and TF-SBRT cohorts, respectively (P = .29), no statistically significant difference was found in overall survival (P = .86), progression-free survival (P = .95), local failure (P = .95), nodal failure (P = .91), and distant failure (P = .49) at 24 months. At 1 and 2 years, the overall survival rates were 86.1% and 63.2% for the SF-SBRT cohort and 80.8% and 61.6% for the TF-SBRT cohort, respectively. At 1 and 2 years, the local control rates were 95.1% and 87.8% for the SF-SBRT cohort and 92.7% and 86.2% for the TF-SBRT cohort, respectively. Both regimens were well tolerated.

CONCLUSION

Despite more patients with poor performance status in the SF-SBRT cohort, the SF- and TF-SBRT regimens showed no differences in clinical outcomes. SF-SBRT is now our standard approach.

A modified formula for dose calculations of stereotactic ablative body radiotherapy for non-small cell lung cancer

To provide a modified formula consistent with the Monte Carlo (MC) algorithm for dose calculations during stereotactic ablative body radiotherapy for non-small cell lung cancer. Seventy CyberKnife treatment plans were calculated and analyzed by MC and ray-tracing (RT) algorithms, separately. Parameters of treatment plans were compared, and those associated with differences of dose distributions were analyzed to establish a modified formula. Gross tumor volume and tumor tracking volume (TTV) were defined as the evident disease on the sequences of the window width and level of the lung and the mediastinum. Additionally, the formula was validated by another 20 plans. The prescription dose of the 90 patients was 60 Gy/5f. The RT algorithm overestimated the planning target volume (PTV) D₉₅ by an average of 8.59 Gy and the gross tumor volume D₉₉ by an average of 5.84 Gy. The homogeneity index of PTV was underestimated by 0.11 on average, whereas the conformity index and new conformity index was underestimated by 0.05. The RT algorithm overestimated the dose distribution to the spinal cord by 2.23 Gy, the esophagus by 1.96 Gy, the trachea by 1.89 Gy, the left-sided bronchus by 1.77 Gy, the right-sided bronchus by 1.64 Gy, and the heart by 2.16 Gy. The average whole-lung dose volumes of lung tissues and dose volumes of V₅ were overestimated by 2.69 Gy and 7.52%, respectively. A power function distribution (R² = 0.8626) was confirmed between PTV D₉₅ and TTV volumes. PTV D₉₅ calculated by the MC algorithm could be computed easily with TTV and PTV D₉₅ calculated by the RT algorithm based on the formula. The modified equation was more consistent with MC algorithm than with other formula, which could be a reference to those not accessible to the MC algorithm.

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.

[Stereotactic lung radiotherapy: Technical setting up on Novalis Tx® and single centre prospective study of the 100 first malignant pulmonary nodules treated at centre Jean-Perrin]

PURPOSE

Description of the treatment technique of stereotactic lung radiotherapy on Novalis Tx^® and prospective study of the first 100 pulmonary nodules treated at centre Jean-Perrin (France).

MATERIAL AND METHODS

From October 2012 to December 2015, 100 inoperable pulmonary nodules (62 stage I non-small-cell lung cancer and 38 metastases) of 90 patients with a mean age of 68.2 years (range: 46-89 years) were prospectively treated with dynamic arctherapy on Novalis Tx^®. Mean gross tumour and planning target volumes were respectively 6.9 cm³ (range: 0.2-31.4 cm³) and 38.7 cm³ (range: 1.7-131 cm³), which correspond to diameters equal to 2.3cm and 4.2cm. Prescribed doses to the 80% isodose line were 54Gy in three fractions for peripheral non-small-cell lung cancer, 50Gy in five fractions for central non-small-cell lung cancer and 45Gy in three fractions for lung metastases. Clinical and radiological follow-up was done every three months with RECIST criteria for efficacy and NCI-CTCAE v4 scale for toxicity. Median follow-up was 12.5 months.

RESULTS

Complete response was observed in 23.8% of cases. Local control rates were 100% and 90.7% respectively at 12 and 24 months, with 96% at 24 months for stage I non-small-cell lung cancer. Overall survival rates of patients with stage I non-small-cell lung cancer were 77.4% and 73.5% at 12 and 24 months (median overall survival was 32 months). Diffusing capacity of the lungs for carbon monoxide corrected for alveolar volume below 40% was significantly associated to a poor prognostic factor on univariate analysis (P=0.00013). At least three deaths were due to an acute respiratory failure, which correspond to about 4.8% of grade 5 radiation pneumonitis. Overall survival rate for metastatic patients were 95.2% and 59.5% respectively at 12 and 24 months (median overall survival was 25 months); 23.3% of grade 2 or less radiation pneumonitis, 7.8% of grade 2 or less radiation dermatitis, 2.2% of asymptomatic ribs fracture and 3.3% of chest pains were observed.

CONCLUSION

Stereotactic lung radiotherapy is an effective treatment for inoperable stage I non-small-cell lung cancer and lung oligometastases of well informed and selected patients. Initial respiratory state, and especially the diffusing capacity of the lungs for carbon monoxide corrected for alveolar volume, seems to be important for tolerance.

A systematic review of outcomes following stereotactic ablative radiotherapy in the treatment of early-stage primary lung cancer

Stereotactic ablative body radiotherapy (SABR) describes a radiotherapy (RT) technique where high doses of radiation are precisely delivered to an extracranial target within the body, using either a single fraction of RT or using multiple small numbers of fractions. SABR has now become the standard of care treatment for patients with early-stage non-small-cell lung cancer (NSCLC) for whom surgery is not appropriate. This systematic review considers the evidence supporting the use of SABR in early-stage NSCLC, reported toxicity rates, the use of SABR in centrally located NSCLC, the use of SABR as salvage therapy following surgery or RT, and future potential drug combinations with SABR.

Specific toxicity after stereotactic body radiation therapy to the central chest : A comprehensive review

The toxicity of stereotactic body radiation therapy in the central chest remains an unsettled issue. The collected data concerning the observed complications are poorly understood and are limited in their quantity and quality, thus hampering a precise delineation of treatment-specific toxicity. The majority of complications scored as toxicity grade 5, namely respiratory failure and fatal hemoptysis, are most likely related to multiple competing risks and occurred at different dose fractionation schemas, e. g., 10-12 fractions of 4-5 Gy, 5 fractions of 10 Gy, 3 fractions of 20-22 Gy, and 1 fraction of 15-30 Gy. Further investigations with longer follow-up and more details of patients' pretreatment and tumor characteristics are required. Furthermore, satisfactory documentation of complications and details of dosimetric parameters, as well as limitation of the wide range of possible fractionation schemes is also warranted for a better understanding of the risk factors relevant for macroscopic damage to the serially organized anatomic structure within the central chest.

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

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

Challenges in radiobiological modeling: can we decide between LQ and LQ-L models based on reviewed clinical NSCLC treatment outcome data?

Aim

To study the dose-response of stage I non-small-cell lung cancer (NSCLC) in terms of long-term local tumor control (LC) after conventional and hypofractionated photon radiotherapy, modeled with the linear-quadratic (LQ) and linear-quadratic-linear (LQ-L) approaches and to estimate the clinical α/β ratio within the LQ frame.

Material and methods

We identified studies of curative radiotherapy as single treatment through MedLine search reporting 3-year LC as primary outcome of interest. Logistic models coupled with the biologically effective dose (BED) at isocenter and PTV edge according to both the LQ and LQ-L models with α/β = 10 Gy were fitted. Additionally, α/β was estimated from direct LQ fits.

Results

Thirty one studies were included reporting outcome of 2319 patients. The LQ-L fit yielded a significant value of 11.0 ± 5.2 Gy for the dose threshold (D_t) for BED₁₀ at the isocenter. The LQ and LQ-L fits did not differ substantially. Concerning the estimation of α/β, the value obtained from the direct LQ fit for the complete fractionation range was 3.9 [68 % CI: 2.2–9.0] Gy (p > 0.05).

Conclusion

Both LQ and LQ-L fits can model local tumor control after conventionally and hypofractionated irradiation and are robust methods for predicting clinical effects. The observed dose-effect for local control in NSCLC is weaker at high doses due to data dispersion. For BED₁₀ values of 100–150 Gy in ≥3 fractions, the differences in isoeffects predicted by both models can be neglected.

Electronic supplementary material

The online version of this article (doi:10.1186/s13014-016-0643-5) contains supplementary material, which is available to authorized users.

Stereotactic Ablative Radiotherapy (SABR) in Patients with Medically Inoperable Peripheral Early Stage Lung Cancer: Outcomes for the First UK SABR Cohort

AIMS

To report outcomes for the first UK cohort treated for early stage peripheral lung cancer using stereotactic ablative radiotherapy (SABR).

MATERIALS AND METHODS

Patients were included who received SABR between May 2009 and May 2012. Electronic medical records were reviewed for baseline characteristics, treatment details and outcomes. Patients were treated according to the UK SABR Consortium Guidelines. Univariate and multivariate Cox regression was used to determine factors that influenced overall survival and local control.

RESULTS

In total, 273 patients received SABR for 288 lesions in the time period examined. The median follow-up was 19.7 months. The median overall survival for all patients was 27.3 months, with 1, 2 and 3 year overall survival of 78.0, 54.9 and 38.6%, respectively. The 1, 2 and 3 year rates of local control were 98.2, 95.7 and 95.7%, respectively. All patients completed the planned course of treatment and rates of Common Toxicity Criteria grade 3+ toxicity were low. On multivariate analysis, patients with Medical Research Council (MRC) breathlessness scores of 3-5 had worse overall survival compared with patients with scores of 1-2 (hazard ratio: 2.10; 95% confidence interval: 1.25-3.59) and the presence of histological diagnosis conferred improved overall survival (hazard ratio: 0.54; 95% confidence interval: 0.31-0.93), probably reflecting that patients who are considered well enough to undergo biopsy are generally fitter overall. No factors were identified that significantly influenced local control.

CONCLUSIONS

SABR is an effective and well-tolerated treatment option for patients with early stage peripheral lung cancer who are not suitable for surgery. No patient cohort was identified in whom SABR was considered inappropriate. This series adds to the existing positive data that support SABR for this patient group.

Long-term survival in metastasized leiomyosarcoma: a case report and review of the literature

BACKGROUND

Leiomyosarcoma of the mesosigma is a very rare entity, with low 5-year survival rates. Treatment consists of resection of the primary tumor and, if applicable, of synchronous or metachronous metastases. Local treatment options for metastatic disease should be exploited as long as possible, as response to chemotherapy is reportedly disappointing. Stereotactic radiotherapy is a fairly new locally effective treatment option which has been well established in stereotactic radiotherapy of lung tumors. Whether repeated stereotactic radiotherapy sessions for treatment of lung metastases can be safely and successfully performed over a long time period is not yet well documented.

CASE REPORT

We present the case of a 71-year-old female patient who had a primary diagnosis of lung metastases 12 years ago. Atypical resections of 4 lung metastases were performed in 2001 and 2002. Between 2004 and 2011, 7 sessions of stereotactic body irradiation of lung metastases were performed. All stereotactic treatment were tolerated well (no radiation pneumonitis, FEV1 was 1.3 L [67.8%] in 2004 and 0.99 L [56.3%] in 2011).

CONCLUSIONS

The present case could demonstrate that a repetitive treatment of lung metastases with multiple stereotactic radiotherapy sessions can lead to long-term survival with a good quality of life.

Role of gross tumor volume in the prognosis of non-small cell lung cancer treated with 3D conformal radiotherapy: a meta-analysis

PURPOSE

Three-dimensional conformal radiotherapy (3D-CRT) has become widely applied in patients with non-small cell lung cancer (NSCLC), and gross tumor volume (GTV) is a reliable index for predicting prognosis in patients with NSCLC. This meta-analysis investigated the association between GTV and prognosis in patients with NSCLC after 3D-CRT.

METHODS

Electronic bibliographic databases were searched to identify articles related to NSCLC and 3D-CRT. The search results were carefully screened, using predetermined selection criteria, to select the most relevant studies. Newcastle-Ottawa Scale criteria were applied by 2 reviewers independently to evaluate the quality of the methodology of each included article., Based on GTV, each patient was assigned to either the study group (large GTV [≥112 cm(3)]) or the control group (small GTV [<112 cm(3)]), and the mean rates of overall survival (OS) and survival at 1, 3, and 5 years were calculated in each group. Summary hazard ratio (HR) with 95% CI was calculated.

FINDINGS

The data from 10 cohort studies were incorporated into the current meta-analysis (1473 patients; study group, 773; control group, 700). The OS in the study group was significantly less than that in the control group (HR = 1.52; 95% CI, 1.10-1.94; P < 0.01). The study and control groups also had significantly different survival rates at 1 year (HR = 1.27; 95% CI, 1.10-1.46, P = 0.01), 3 years (HR = 2.06; 95% CI, 1.63-2.61; P < 0.01), and 5 years (HR = 2.25; 95% CI, 1.63-3.10; P < 0.01). Findings from funnel plots and Egger tests of the OS and 3-year survival rate suggested no publication bias. With respect to the 1- and 5-year survival rates, however, the funnel plots and Egger tests demonstrated publication bias among the included studies.

IMPLICATIONS

The relatively small number of studies and small sample size, as well as the lack of a specific and standard method of defining small and large GTV, may have influenced the credibility and reliability of our results. The findings suggest that GTV influences prognosis in patients with NSCLC after 3D-CRT. However, further studies with larger sample sizes are needed to confirm our finding that a larger GTV is negatively associated with NSCLC prognosis after 3D-CRT.

Stereotactic radiotherapy for early stage non-small cell lung cancer

Stereotactic body radiotherapy (SBRT) represents a consolidated treatment option for patients with medically inoperable early stage non-small cell lung cancer (NSCLC). The clinical evidence accumulated in the past decade supports its use as an alternative to surgery with comparable survival outcomes. Due to its limited toxicity, SBRT is also applicable to elderly patients with very poor baseline pulmonary function or other severe comorbidities. Recent comparative studies in operable patients raised the issue of the possible use of SBRT also for this subgroup, with quite promising results that still should be fully confirmed by prospective trials with long-term follow-up. Aim of this review is to summarize and discuss the major studies conducted over the years on SBRT and to provide data on the efficacy and toxicity of this radiotherapy technique for stage I NSCLC. Technical aspects and quality of life related issues are also discussed, with the goal to provide information on the current role and limitations of SBRT in clinical practice.

Textural features in pre-treatment [F18]-FDG-PET/CT are correlated with risk of local recurrence and disease-specific survival in early stage NSCLC patients receiving primary stereotactic radiation therapy

Background

Textural features in FDG-PET have been shown to provide prognostic information in a variety of tumor entities. Here we evaluate their predictive value for recurrence and prognosis in NSCLC patients receiving primary stereotactic radiation therapy (SBRT).

Methods

45 patients with early stage NSCLC (T1 or T2 tumor, no lymph node or distant metastases) were included in this retrospective study and followed over a median of 21.4 months (range 3.1–71.1). All patients were considered non-operable due to concomitant disease and referred to SBRT as the primary treatment modality. Pre-treatment FDG-PET/CT scans were obtained from all patients. SUV and volume-based analysis as well as extraction of textural features based on neighborhood gray-tone difference matrices (NGTDM) and gray-level co-occurence matrices (GLCM) were performed using InterView Fusion™ (Mediso Inc., Budapest). The ability to predict local recurrence (LR), lymph node (LN) and distant metastases (DM) was measured using the receiver operating characteristic (ROC). Univariate and multivariate analysis of overall and disease-specific survival were executed.

Results

7 out of 45 patients (16%) experienced LR, 11 (24%) LN and 11 (24%) DM. ROC revealed a significant correlation of several textural parameters with LR with an AUC value for entropy of 0.872. While there was also a significant correlation of LR with tumor size in the overall cohort, only texture was predictive when examining T1 (tumor diameter < = 3 cm) and T2 (>3 cm) subgroups. No correlation of the examined PET parameters with LN or DM was shown.

In univariate survival analysis, both heterogeneity and tumor size were predictive for disease-specific survival, but only texture determined by entropy was determined as an independent factor in multivariate analysis (hazard ratio 7.48, p = .016). Overall survival was not significantly correlated to any examined parameter, most likely due to the high comorbidity in our cohort.

Conclusions

Our study adds to the growing evidence that tumor heterogeneity as described by FDG-PET texture is associated with response to radiation therapy in NSCLC. The results may be helpful into identifying patients who might profit from an intensified treatment regime, but need to be verified in a prospective patient cohort before being incorporated into routine clinical practice.

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

BACKGROUND

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

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

SBRT in operable early stage lung cancer patients

Since decades the gold standard for treatment of early stage non-small cell lung cancer (NSCLC) is surgical lobectomy plus mediastinal lymph node dissection. Patients in worse health status are treated with sublobar resection or radiation treatment. With development of stereotactic-body-radiotherapy (SBRT), outcome of patients treated with radiation was substantially improved. Comparison of SBRT and surgical techniques is difficult due to the lack of randomized trials. However, all available evidence in form of case control studies of population based studies show equivalence between sublobar resection and SBRT indicating that SBRT-when performed by a trained and experienced team-should be offered to all high-risk surgical patients. For patients not willing to take the risk of lobectomy and therefore refusing surgery, SBRT is an excellent treatment option.