Stereotactic body radiotherapy (SBRT) for solitary pulmonary nodules clinically diagnosed as lung cancer with no pathological confirmation: comparison with non-small-cell lung cancer

Stereotactic vs Hypofractionated Radiotherapy for Inoperable Stage I Non-Small Cell Lung Cancer: The LUSTRE Phase 3 Randomized Clinical Trial

Importance

Stereotactic body radiotherapy (SBRT) is widely used for stage I medically inoperable non-small cell lung cancer (NSCLC), yet varied results from randomized clinical trials (RCTs) and concerns in treating centrally located tumors persist.

Objective

To examine whether SBRT would improve local control (LC) compared with hypofractionated conventional radiotherapy (CRT).

Design, Setting, and Participants

This phase 3 RCT was conducted in 16 Canadian centers. Patients with medically inoperable stage I (≤5 cm) NSCLC were randomized 2:1 to SBRT of 48 Gy in 4 fractions (peripheral NSCLC) or 60 Gy in 8 fractions (central NSCLC) vs CRT of 60 Gy in 15 fractions. Data were collected from May 2014 to January 2020, and data were analyzed from July 2022 to July 2023.

Interventions

SBRT or CRT.

Main Outcomes and Measures

The primary objective was to determine the effectiveness of SBRT compared with CRT based on LC at 3 years. Secondary outcomes included event-free survival, overall survival, and toxic effects. All radiation plans were subject to real-time/final review. Local failures were centrally adjudicated. The study was designed to detect a 3-year LC improvement of SBRT from 75% to 87.5%. The target sample size was 324 patients.

Results

Of 233 included patients, 119 (51.1%) were male, and the mean (SD) age was 75.4 (7.7) years; the median (IQR) follow-up was 36.1 (26.4-52.8) months. A total of 154 patients received SBRT and 79 received CRT. The 3-year LC was 87.6% (95% CI, 81.9%-93.4%) for SBRT and 81.2% (95% CI, 71.9%-90.5%) for CRT (hazard ratio [HR], 0.61; 95% CI, 0.31-1.20; P = .15). The HR was 1.02 (95% CI, 0.72-1.45; P = .87) for event-free survival and 1.18 (95% CI, 0.80-1.76; P = .40) for overall survival. Minimal acute toxic effects were observed. Among those randomized to SBRT, late grade 3 or 4 toxic effects occurred in 5 of 45 (11%) with central NSCLC and 2 of 109 (1.8%) with peripheral NSCLC; among those randomized to CRT, in 1 of 19 (5%) with central NSCLC and 1 of 60 (2%) with peripheral NSCLC. One patient who received SBRT for an ultracentral lesion (target overlapping proximal bronchus) experienced a possible treatment-related grade 5 event (hemoptysis).

Conclusions and Relevance

This RCT compared lung SBRT with hypofractionated CRT that included central/ultracentral tumors. No difference was detected in LC between groups. Severe toxic effects were limited, including patients with central tumors. The trial provides important prospective data evaluating SBRT; however, further research is necessary to determine if SBRT is more effective than CRT for peripheral and central NSCLC.

Trial Registration

ClinicalTrials.gov Identifier: NCT03924869.

Advances in the Treatment of Pulmonary Nodules

BACKGROUND

Early detection and accurate diagnosis of pulmonary nodules are crucial for improving patient outcomes. While surgical resection of malignant nodules is still the preferred treatment option, it may not be feasible for all patients. We aimed to discuss the advances in the treatment of pulmonary nodules, especially stereotactic body radiotherapy (SBRT) and interventional pulmonology technologies, and provide a range of recommendations based on our expertise and experience.

SUMMARY

Interventional pulmonology is an increasingly important approach for the management of pulmonary nodules. While more studies are needed to fully evaluate its long-term outcomes and benefits, the available evidence suggests that this technique can provide a minimally invasive and effective alternative for treating small malignancies in selected patients. We conducted a systematic literature review in PubMed, designed a framework to include the advances in surgery, SBRT, and interventional pulmonology for the treatment of pulmonary nodules, and provided a range of recommendations based on our expertise and experience.

KEY MESSAGES

As such, alternative therapeutic options such as SBRT and ablation are becoming increasingly important and viable. With recent advancements in bronchoscopy techniques, ablation via bronchoscopy has emerged as a promising option for treating pulmonary nodules. This study reviewed the advances of interventional pulmonology in the treatment of peripheral lung cancer patients that are not surgical candidates. We also discussed the challenges and limitations associated with ablation, such as the risk of complications and the potential for incomplete nodule eradication. These advancements hold great promise for improving the efficacy and safety of interventional pulmonology in treating pulmonary nodules.

Comparison of long-term outcomes of stereotactic body radiotherapy (SBRT) via Helical tomotherapy for early-stage lung cancer with or without pathological proof

BACKGROUND

Stereotactic body radio therapy (SBRT) has emerged as a standard treatment option for nonsurgical candidates with early-stage non-small cell lung cancer (NSCLC). Pathological proof is sometimes difficult to obtain in patients with solitary pulmonary nodules (SPNs). We aimed to compare the clinical outcomes of stereotactic body radiotherapy via helical tomotherapy (HT-SBRT) for early-stage lung cancer patients with or without a pathological diagnosis.

METHODS

Between June 2011 and December 2016, we treated 119 lung cancer patients with HT-SBRT, including 55 with a clinical diagnosis and 64 with a pathological diagnosis. Survival outcomes, including local control (LC), progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS), were compared between two cohorts with and without a pathological diagnosis.

RESULTS

The median follow-up for the whole group was 69 months. Patients with a clinical diagnosis were significantly older (p = 0.002). No significant differences were observed between the clinical and pathological diagnosis cohorts in terms of the long-term outcome, with 5-year LC, PFS, CSS, and OS of 87% versus 83% (p = 0.58), 48% versus 45% (p = 0.82), 87% versus 84% (p = 0.65), and 60% versus 63% (p = 0.79), respectively. Recurrence patterns and toxicity were also similar.

CONCLUSIONS

Empiric SBRT appears to be a safe and effective treatment option in a multidisciplinary setting when patients with SPNs highly suggestive of malignancy are unable/refuse to obtain a definitive pathological diagnosis.

European Respiratory Society guideline on various aspects of quality in lung cancer care

This European Respiratory Society guideline is dedicated to the provision of good quality recommendations in lung cancer care. All the clinical recommendations contained were based on a comprehensive systematic review and evidence syntheses based on eight PICO (Patients, Intervention, Comparison, Outcomes) questions. The evidence was appraised in compliance with the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach. Evidence profiles and the GRADE Evidence to Decision frameworks were used to summarise results and to make the decision-making process transparent. A multidisciplinary Task Force panel of lung cancer experts formulated and consented the clinical recommendations following thorough discussions of the systematic review results. In particular, we have made recommendations relating to the following quality improvement measures deemed applicable to routine lung cancer care: 1) avoidance of delay in the diagnostic and therapeutic period, 2) integration of multidisciplinary teams and multidisciplinary consultations, 3) implementation of and adherence to lung cancer guidelines, 4) benefit of higher institutional/individual volume and advanced specialisation in lung cancer surgery and other procedures, 5) need for pathological confirmation of lesions in patients with pulmonary lesions and suspected lung cancer, and histological subtyping and molecular characterisation for actionable targets or response to treatment of confirmed lung cancers, 6) added value of early integration of palliative care teams or specialists, 7) advantage of integrating specific quality improvement measures, and 8) benefit of using patient decision tools. These recommendations should be reconsidered and updated, as appropriate, as new evidence becomes available.

Lung stereotactic radiation therapy: Intercomparison of irradiation devices in terms of outcome and predictive factors

PURPOSE

To compare three different radiotherapy devices able to perform pulmonary stereotactic radiotherapy: CyberKnife® (CK), Helical Tomotherapy® (HT), and volumetric modulated arc therapy (VMAT). This study aims to define the patients' outcome in terms of SBRT efficacy and toxicities depending of the device choice.

MATERIALS AND METHODS

We retrospectively analyzed the clinical, radiological, and dosimetric data of patients treated with lung SBRT between 2016 and 2020 at Lausanne University Hospital, using the Chi² test for proportions, the t-test for means comparisons, the Kaplan-Meier method for survival, and the Log-rank test and Cox-regression for intergroups comparisons.

RESULTS

We identified 111 patients treated by either CK (59.9%), VMAT (38.0%), or HT (2.1%). Compared to other techniques, CK treated comparable gross tumor volume (GTV; 2.1 vs. 1.4cm³, P=0.84) with smaller planning treatment volume (PTV; 12.3 vs. 21.9cm³, P=0.013) and lower V5 (13.5 vs. 19.9cm³, P=0.002). Local control rates at 2years were not different whatever the irradiation device, respectively of 96.2% (range, 90.8-100) and 98.1% (range, 94.4-100), P=0.68. Toxicity incidence significantly increased with V5 value>17.2% (56.0 vs. 77.4%, P=0.021).

CONCLUSION

Compared to other SBRT techniques, CK treatments permitted to treat comparable GTV with reduced PTV and V5. Toxicity incidence was less frequent when reducing the V5. CK is particularly attractive in case of multiple courses of lung SBRT or lung reirradiation.

Outcomes for Elective Open and Thoracoscopic Surgical Lung Biopsies in the United States and Temporal Trends

Objective

To elucidate the outcomes of surgical lung biopsies (SLBs) performed for indications other than interstitial lung disease (ILD) and stratify outcomes according to procedural approach (open vs thoracoscopic).

Patients and Methods

Using the Nationwide Inpatient Sample database (January 1, 2008, through December 31, 2014), we identified elective hospitalizations with International Classification of Diseases, Ninth Revision, Clinical Modification codes for open (33.28) and thoracoscopic (33.20) SLB. We stratified cases by the presence/absence of ILD. Our primary outcome was in-hospital mortality.

Results

There were 47,469 hospitalizations for elective SLB (26,540 [55.9%] thoracoscopic) during the study period; 23,930 patients (50.5%) were women, 17,019 (35.9%) had ILD, and the mean ± SD age was 62.6±13.0 years. Over the study period, thoracoscopic increasingly replaced open SLB, and in-hospital mortality declined (3.5% [308 of 8678] in 2008 vs 2.5% [130 of 5215] in 2014; P<.001). Mortality following thoracoscopic SLB was 2.1% (550 of 26,519; 1.9% [214 of 11,513] in ILD and 2.2% [336 of 15,006] in non-ILD), and mean ± SD length of stay was 5.1±6.9 days. Open SLBs had worse outcomes; mortality was 3.7% (782 of 20,914; 3.9% [214 of 5487] in ILD and 3.7% [568 of 15,427] in non-ILD), and mean ± SD length of stay was 8.2±12 days. On multivariable analysis, male sex, advanced age, ILD, and higher comorbidity index correlated with higher mortality. Conversely, lower mortality was observed among individuals with obesity (odds ratio, 0.73; 95% CI, 0.60-0.88) and those who had their thoracoscopic SLBs performed at high-volume centers (top quartile) (odds ratio, 0.73; 95% CI, 0.57-0.94).

Conclusion

Surgical lung biopsy is more often performed for non-ILD indications. Interstitial lung disease was an independent predictor of poor outcomes, but the unadjusted outcomes were worse in the non-ILD cohort due to differences in patient characteristics. Thoracoscopic SLBs performed at high-volume centers had superior outcomes.

The Clinical Outcomes, Prognostic Factors and Nomogram Models for Primary Lung Cancer Patients Treated With Stereotactic Body Radiation Therapy

PURPOSE

Stereotactic body radiation therapy (SBRT) is a standard treatment for early primary lung cancer patients. However, there are few simple models for predicting the clinical outcomes of these patients. Our study analyzed the clinical outcomes, identified the prognostic factors, and developed prediction nomogram models for these patients.

MATERIALS AND METHODS

We retrospectively analyzed 114 patients with primary lung cancer treated with SBRT from 2012 to 2020 at our institutions and assessed patient's clinical outcomes and levels of toxicity. Kaplan-Meier analysis with a log-rank test was used to generate the survival curve. The cut-off values of continuous factors were calculated with the X-tile tool. Potential independent prognostic factors for clinical outcomes were explored using cox regression analysis. Nomograms for clinical outcomes prediction were established with identified factors and assessed by calibration curves.

RESULTS

The median overall survival (OS) was 40.6 months, with 3-year OS, local recurrence free survival (LRFS), distant disease-free survival (DDFS) and progression free survival (PFS) of 56.3%, 61.3%, 72.9% and 35.8%, respectively, with grade 3 or higher toxicity rate of 7%. The cox regression analysis revealed that the clinical stage, immobilization device, and the prescription dose covering 95% of the target area (D95) were independent prognostic factors associated with OS. Moreover, the clinical stage, and immobilization device were independent prognostic factors of LRFS and PFS. The smoking status, hemoglobin (Hb) and immobilization device were significant prognostic factors for DDFS. The nomograms and calibration curves incorporating the above factors indicated good predictive accuracy.

CONCLUSIONS

SBRT is effective and safe for primary lung cancer. The prognostic factors associated with OS, LRFS, DDFS and PFS are proposed, and the nomograms we proposed are suitable for clinical outcomes prediction.

A Propensity-Matched Analysis of Survival of Clinically Diagnosed Early-Stage Lung Cancer and Biopsy-Proven Early-Stage Non-Small Cell Lung Cancer Following Stereotactic Ablative Radiotherapy

Purpose

Stereotactic body radiotherapy (SBRT) has been increasingly regarded as a reasonable option for early-stage lung cancer patients without pretreatment pathologic results, but the efficacy and safety in a Chinese population remains unclear. The aim of this study was to compare survival outcomes and toxicities between patients with clinically diagnosed early-stage lung cancer or biopsy-proven early-stage non-small cell lung cancer and to demonstrate the rationality of this treatment.

Material and Methods

From May 2012 to December 2018, 56 patients with clinically diagnosed early-stage lung cancer and 60 patients with early-stage biopsy-proven were selected into non-pathological group and pathological group, respectively. Propensity score matching (PSM) was performed to reduce patient selection bias. Survival analysis with log-rank test was used to assess the differences of treatment outcomes, which included local control (LC), progression-free survival (PFS), and overall survival (OS).

Results

The median age was 76 (range 47–93) years, and the median follow-up time was 58.3 (range 4.3–95.1) months in the cohort without pathologic results. The median age was 74 (range 57–88) years, and the median follow-up time was 56.3 (range 2.6–94) months in the cohort with pathologic results. 45 matched-pair were analyzed. The 5-year LC, PFS, and OS rates in matched-pair patients with or without pathologic biopsy were 85.5% and 89.8%, 40.6% and 70.9%, and 63.2% and 76.1%, respectively. On Kaplan-Meier survival analysis after PSM analysis, there was no significant difference between patients with pathologic results versus patients with no pathologic results in terms of LC (P= 0.498) and OS (P=0.141). Of the matched-pair patients treated with SBRT, only 1 patient experienced grade 3 or above radiation pneumonitis.

Conclusion

For early-stage lung cancer patients with medically inoperable or not suitable for invasive diagnosis, SBRT may be a good local treatment.

Use and Outcomes of SBRT for Early Stage NSCLC Without Pathologic Confirmation in the Veterans Health Care Administration

Purpose

Stereotactic body radiation therapy (SBRT) use has increased among patients without pathologic confirmation (PC) of lung cancer. Empirical SBRT without PC raises concerns about variation in workup and patient selection, but national trends have not been well described. In this study, we assessed patterns of empirical SBRT use, workup, and causes of death among a large national non-small cell lung cancer (NSCLC) cohort.

Methods and Materials

We identified 2221 patients treated with SBRT for cT1-T2aN0M0 NSCLC in the Veterans Affairs health care system from 2008 to 2015. We reviewed their pretreatment workup and assessed associations between absence of PC and clinical and demographic factors. We compared causes of death between PC and non-PC groups and used Cox proportional hazards modeling to compare overall survival and lung cancer specific survival (LCSS) between these groups.

Results

Treatment without PC varied from 0% to 61% among Veterans Affairs medical centers, with at least 5 cases of stage I NSCLC. Overall, 14.9% of patients were treated without PC and 8.8% did not have a biopsy attempt. Ten percent of facilities were responsible for almost two-thirds (62%) of cases of treatment without PC. Of non-PC patients, 95.5% had positron emission tomography scans, 40.6% had biopsy procedures attempted, and 12.7% underwent endobronchial ultrasound. Non-PC patients were more likely to have cT1 tumors and live outside the histoplasmosis belt. Age, sex, smoking status, and Charlson comorbidity index were similar between groups. Lung cancer was the most common cause of death in both groups. Overall survival was similar between groups, whereas non-PC patients had better LCSS (hazard ratio = 0.77, P = .031).

Conclusions

Empirical SBRT use varied widely among institutions and appropriate radiographic workup was consistently used in this national cohort. Future studies should investigate determinants of variation and reasons for higher LCSS among non-PC patients.

To biopsy or not to biopsy? Outcomes following stereotactic body radiotherapy (SBRT) for biopsy-confirmed versus radiologically-diagnosed primary lung cancer in a single Australian institution

INTRODUCTION

Obtaining tissue diagnosis for lung cancer can sometimes be difficult and unsafe. We evaluated outcomes of biopsy-confirmed versus radiologically-diagnosed lung cancer treated with stereotactic body radiotherapy (SBRT).

METHODS

A single-institutional retrospective cohort of lung cancer patients treated with SBRT between February 2014 and October 2018. Outcomes of interest were: local failure (LF), distant failure (DF), and overall survival (OS). Probability of LF, DF, and OS were estimated using the Kaplan-Meier method. Differences in outcomes between biopsy-confirmed versus radiologically-diagnosed lung cancer were evaluated using the log-rank test.

RESULTS

Sixty-five lung lesions in 61 patients were treated with SBRT. Mean age was 75.6 years. Twenty-seven patients (44.3%) were ECOG 2-3. Thirty-nine patients (64%) were radiologically-diagnosed. There were five cases of LF observed at median of 12.8 months post-SBRT and 12-month LF-free survival was 96% (95% CI, 86-99%), with no differences between groups (p = 0.1). Sixteen patients developed DF, with 12-month DF-free survival of 84% (95% CI, 71-91%), and no difference between groups (p = 0.06). Sixteen deaths were reported at a median of 12.5 months post-SBRT, with 12-month OS of 85% (95% CI, 73-92%), and no differences between study groups (p = 0.5). No grade 3 toxicities were reported.

CONCLUSION

The oncological outcomes were similar in patients with early lung cancer treated with SBRT with or without biopsy-confirmation. In situations where tissue diagnosis is not feasible or unsafe, it is not unreasonable to offer SBRT based on clinical and radiological suspicion following multidisciplinary discussions.

Stereotactic radiotherapy for early stage non-small cell lung cancer: current standards and ongoing research

Stereotactic body radiation therapy (SBRT) allows for the non-invasive and precise delivery of ablative radiation dose. The use and availability of SBRT has increased rapidly over the past decades. SBRT has been proven to be a safe, effective and efficient treatment for early stage non-small cell lung cancer (NSCLC) and is presently considered the standard of care in the treatment of medically or functionally inoperable patients. Evidence from prospective randomized trials on the optimal treatment of patients deemed medically operable remains owing, as three trials comparing SBRT to surgery in this cohort were terminated prematurely due to poor accrual. Yet, SBRT in early stage NSCLC is associated with favorable toxicity profiles and excellent rates of local control, prompting discussion in regard of the treatment of medically operable patients, where the standard of care currently remains surgical resection. Although local control in early stage NSCLC after SBRT is high, distant failure remains an issue, prompting research interest to the combination of SBRT and systemic treatment. Evolving advances in SBRT technology further facilitate the safe treatment of patients with medically or anatomically challenging situations. In this review article, we discuss international guidelines and the current standard of care, ongoing clinical challenges and future directions from the clinical and technical point of view.

Clinical Outcomes After Stereotactic Body Radiation Therapy for Early Stage Non-Small Cell Lung Cancer: A Single Institutional Study

Introduction The standard of care for early-stage non-small cell lung cancer (NSCLC) is surgery. However, for medical inoperable patients stereotactic body radiation therapy (SBRT) is an alternative method. The aim of the study is to assess the overall survival (OS), progression-free survival (PFS) and local control (LC) of patients diagnosed with NSCLC in Manitoba, Canada, between 2013 and 2017 and managed with SBRT. Materials and methods This retrospective study included a total of 158 patients (60.13% of the population were females) that were diagnosed with stage I-II NSCLC and were treated with lung SBRT between 2013 and 2017 in Manitoba. Demographics and clinical data were retrospectively extracted from the electronic patient record. Kaplan-Meier and Cumulative incidence curves were used to describe the OS, PFS, and LC outcomes. Results From the 158 patients, 32 patients were treated with 60 Gy in eight fractions, while 121 patients were treated with 48 Gy in four fractions. Only 85 patients had biopsy-proven NSCLC. The median OS was 2.87 years (95% confidence interval [CI] 2.16-3.43). OS rates at one and two years were 85% and 66%, respectively. The median PFS was 2.03 years (95% CI 1.65-2.77). Furthermore, one-year and two-year PFS rates were 77% and 51%, respectively. Only 10 patients progressed locally at one year and 17 at two years, making the LC rate 93% at the one-year and 87% at the two-year mark. Conclusion These findings add to a growing evidence base supporting SBRT in the treatment of clinically suspected and biopsy-proven early-stage NSCLC patients.

Stereotactic body radiation therapy for empirically treated hypermetabolic lung lesions: a single-institutional experience identifying the Charlson score as a key prognostic factor

Background

Though pathologic evidence for non-small cell lung cancer (NSCLC) is preferred, many patients do not receive a biopsy prior to treatment with stereotactic body radiation therapy (SBRT). This study seeks to analyze the overall survival (OS), local control, and toxicity rates for such patients.

Methods

This retrospective review included patients empirically treated with SBRT for presumed non-metastatic NSCLC at a single institution. Inclusion criteria included a hypermetabolic pulmonary lesion noted on positron emission tomography (PET) imaging but no pathological evidence of NSCLC. Patients with another known metastatic tumor were excluded. Statistical analysis was conducted with Cox proportional hazards analysis, univariate analysis, and the Kaplan-Meier method.

Results

Ninety-one treatments in 90 unique patients met inclusion criteria. Patients were a median 77.9 years at the start of treatment and had a median Charlson score of 7. Pre-treatment standardized uptake value (SUV) was a median 4.5 and 1.5 after treatment. At a median follow-up of 12.9 months, 36-month local control of 91.3% was achieved. Twenty-four-month OS and progression-free survival were 65.4% and 44.8%, respectively. On univariate analysis, biologically effective dose (BED) ≥120 Gy was predictive of improved OS (P=0.001), with 36-month OS of 50.5% for patients with BED ≥120 Gy and only 31.6% for patients with BED <120 Gy. On Kaplan-Meier analysis, Charlson score ≥9 was predictive of decreased OS (P=0.04), and BED ≥120 Gy trended towards improved OS (P=0.08). Thirty-two cases of grade <3 toxicity were reported, and only two cases of grade 3 morbidity (fatigue) were noted.

Conclusions

Local control rates for empiric SBRT treatment for hypermetabolic, non-metastatic NSCLC are similar to those for biopsied NSCLC. OS is primarily dependent on a patient’s overall health status, which can be accurately assessed with the Charlson score. BED ≥120 Gy may also contribute to improved OS.

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.

To Biopsy or Not to Biopsy?: A Matched Cohort Analysis of Early-Stage Lung Cancer Treated with Stereotactic Radiation with or Without Histologic Confirmation

PURPOSE

For nonoperable stage I non-small cell lung cancer, stereotactic body radiation therapy (SBRT) has emerged as a standard treatment option. We aimed to compare the clinical outcomes of lung SBRT between patients with versus without pathologic cancer diagnosis.

METHODS AND MATERIALS

We included patients treated by SBRT for a single pulmonary lesion between July 2009 and July 2017. Patients in the clinical diagnosis group had a positron emission tomography/computed tomography scan showing hypermetabolism, growth of the mass on sequential computed tomography, and were not eligible for biopsy, refused biopsy, or had an inconclusive biopsy. For each of those patients, a matched pair in the pathologic diagnosis group was identified by matching for patient, treatment, and tumoral characteristics. We performed a power calculation to estimate the sample size required to detect a difference arising from a 5% or 15% rate of benign processes in the group without pathology.

RESULTS

A total of 924 lung SBRT treatments were performed among 878 patients from 2009 to 2017. Within this population, 131 patients were treated based on clinical findings. They were matched with 131 patients with a pathologic diagnosis who received treatment. At 3 years, no significant differences were observed in overall survival (hazard ratio [HR], 1.2; 95% confidence interval [CI], 0.7-2.1), local control (HR, 0.9; 95% CI, 0.4-2), or regional (HR, 0.5; 95% CI, 0.2-1.4) or distant recurrence (HR, 0.6; 95% CI, 0.3-1.1).

CONCLUSIONS

In our population, we found no clinically significant difference in patterns of recurrence or survival after lung SBRT for patients who had received clinical versus pathological diagnoses. There was, however, a trend toward more distant recurrences in the pathologic diagnosis group. Our power calculation suggests that data from multiple institutions would be required to rule out a difference in outcomes due to 5% to 15% of clinically diagnosed cases being treated for benign processes.

Stereotactic ablative radiation therapy in lung cancer: an emerging standard

PURPOSE OF REVIEW

Significant advances have been made in the field of stereotactic ablative radiotherapy (SABR) for the treatment of pulmonary neoplasms in recent years. This review aims to summarize recent salient evidence on SABR for early-stage nonsmall cell lung cancer (ES-NSCLC).

RECENT FINDINGS

In medically inoperable patients, SABR remains the standard of care. The optimal SABR dosing regimen is being studied. Comparisons with non-SABR radiotherapy regimens with lower doses per fraction revealed benefit of SABR. In operable patients, no prospective clinical trial comparing SABR and surgery has been completed, although multiple trials are currently underway to address this question. SABR is generally cost-effective and safe in most patients, with preserved patient-reported quality of life. However, increased toxicity with SABR is noted in patients with disease close to, or invading the proximal tracheobronchial tree. Significant SABR-related toxicity and mortality is also reported in patients with coexisting interstitial lung disease. Considerations on pathologic confirmation, surveillance and multiple primaries are also addressed.

SUMMARY

SABR is an effective and safe treatment for inoperable ES-NSCLC. Ongoing trials and comparative effectiveness research will help to clarify SABR's role in various lung cancer indications going forward.

Empiric Radiotherapy for Lung Cancer Collaborative Group multi-institutional evidence-based guidelines for the use of empiric stereotactic body radiation therapy for non-small cell lung cancer without pathologic confirmation

The standard of care for managing early stage non-small cell lung cancer (NSCLC) is definitive surgical resection. Stereotactic body radiation therapy (SBRT) has become the standard treatment for patient who are medically inoperable, and it is increasingly being considered as an option in operable patients. With the growing use of screening thoracic CT scans for patients with a history of heavy smoking, as well as improved imaging capabilities, the discovery of small lung nodes has become a common dilemma. As a result, clinicians are increasingly faced with managing lung nodules in patients in whom diagnostic biopsy is not safe or feasible. Herein, we describe the scope of the problem, tools available for predicting the probability that a lung nodule is a malignancy, staging procedures, benefits of pathology-proven and empiric SBRT, considerations of safety based on location of the lesion of concern, and overall efficacy of SBRT.

Stereotactic ablative radiotherapy (SABR) in early stage non-small cell lung cancer: Comparing survival outcomes in adenocarcinoma and squamous cell carcinoma

PURPOSE

Recent retrospective studies have demonstrated mixed results regarding the histologic association of squamous cell carcinoma (SCC) with reduced overall survival in patients with early-stage non-small cell lung cancer (ES-NSCLC) treated with stereotactic ablative radiotherapy (SABR).

METHODS

We queried the National Cancer Database (NCDB) for ES-NSCLC (T1-2N0, Stage I-IIA) patients with SCC or adenocarcinoma (ADC) treated with SABR. Univariable and multivariable analyses identified characteristics predictive of overall survival. Cox proportional hazard ratios with propensity adjustment were used to mitigate indication bias between the two histologic arms.

RESULTS

Ultimately 15,110 ES-NSCLC patients with either ADC (n = 8,924) or SCC (n = 6,186) were eligible for analysis. Univariable analysis demonstrated a median overall survival of 44 months and 33 months (p < 0.0001) and 5-year overall survival of 36% and 24% (p < 0.0001) in patients diagnosed with ADC and SCC, respectively. SCC histology, remained an independent predictor of worse survival on propensity score matched multivariable comparison (p < 0.0001). Patients with SCC were more likely to have T2 lesions and poorly differentiated grade. Females, African American race, T1 lesions, and age <75 years were also associated with improved survival. Conclusion SCC histology was an independent prognosticator of worse survival in patients with ES-NSCLC treated with SABR, thus corroborating the results of previous studies. Randomized, prospective studies are needed to further validate these findings.

Image-based management of empiric lung stereotactic body radiotherapy (SBRT) without biopsy: Predictors from a 10-year single institution experience

Background

There is emerging reliance on clinical imaging for the diagnosis, prognosis, and treatment evaluation of early stage non‐small cell lung cancer (NSCLC) in patients deemed too high risk for biopsy. We report our experience of clinically diagnosed NSCLC treated empirically with stereotactic body radiotherapy (SBRT) to validate the imaging parameters used for management in this high‐risk population.

Methods

We reviewed 101 empiric lung SBRT cases and profiled imaging specifics of computed tomography and positron emission tomography for diagnosis and follow‐up. Secondarily, we identified potential correlates of disease progression with Cox regression multivariate analysis.

Results

Fifty‐seven men and 43 women aged 45–94 (median 76) were treated with a median dose of 48 Gy in four fractions. The median nodule diameter was 1.6 cm (0.6–4.5 cm) and most were spiculated (n = 58), right‐sided (n = 63), and in the upper lobe (n = 68). Median follow‐up and survival rates were 14 and 28 months, respectively. Local control at three years was 94%. Freedom from any progression at one and three years was 85% and 69%, respectively. Toxicity ≥ grade 3 included two grade 3 dyspneas. A pre‐treatment standard uptake value > 4.1 was the only significant predictor of disease progression.

Conclusion

This study illustrates the instrumental role of modern clinical imaging for the effective management of presumed early stage NSCLC treated with empiric lung SBRT. As lung SBRT without tissue confirmation becomes more common, hopefully these assertions can be prospectively validated.

SBRT for early stage lung cancer: outcomes from biopsy-proven and empirically treated lesions

Aim:

Herein, we compare outcomes in patients treated with lung stereotactic body radiotherapy (SBRT) with and without tissue confirmation.

Methods:

We reviewed 196 patients that underwent lung SBRT for presumed (100 patients) or proven non-small-cell lung cancer (96 patients) over a 10-year period and compared outcomes.

Results:

A total of 196 patients with a median age of 76 underwent lung SBRT to a median dose of 48 Gy in four fractions. Median follow up was 17 months. Local control and overall survival at 3 years was 94 and 58% for the entire group. There was no difference in overall survival, local control, regional control or distant control between the cohorts.

Conclusion:

SBRT is a safe and effective treatment for patients with non-small-cell lung cancer that are medically inoperable with comparable results in empirically treated patients.

Medically inoperable stage I non-small cell lung cancer: best practices and long-term outcomes

Early-stage non-small cell lung cancer (ES-NSCLC) currently represents a minority of all NSCLC diagnoses but, with ongoing refinement and improvement of treatment approaches, is a group with increasing likelihood of long-term disease control and survival. A significant proportion of this population will not be optimal candidates for definitive surgical resection due to tumor characteristics, patient frailty, or comorbid status. The clinical evidence to support the use of stereotactic body radiation therapy (SBRT) in patients with medically inoperable stage I NSCLC is growing as long-term data are obtained. In this review, initial workup, SBRT delivery considerations, recent trial data, and post-treatment surveillance of this population are discussed.

Radiological differential diagnosis between fibrosis and recurrence after stereotactic body radiation therapy (SBRT) in early stage non-small cell lung cancer (NSCLC)

Background

Parenchymal changes after stereotactic body radiation therapy (SBRT) make differential diagnosis between treatment outcomes and disease recurrence often difficult. The purpose of our study was to identify the radiographic features detectable at computed tomography (CT) scan [high-risk features (HRFs)] that allow enough specificity and sensitivity for early detection of recurrence.

Methods

We retrospectively evaluated patients who underwent SBRT for inoperable early stage non-small cell lung cancer (NSCLC). The median delivered dose performed was 50 Gy in 5 fractions prescribed to 80% isodose. All patients underwent chest CT scan before SBRT and at 3, 6, 12, 18, 24 months after, and then annually. Each CT scan was evaluated and benign and HRFs were recorded. ¹⁸F-fluorodeoxyglucose-CT was not used routinely.

Results

Forty-five patients were included (34 males, 11 females; median age: 77 years; stage IA: 77.8%, stage IB: 22.2%; median follow-up: 21.7 months). Two year and actuarial local control was 77%. HRFs were identified in 20 patients. The most significant predictor of relapse was an enlarging opacity at 12 months (P<0.001) with 84.6% sensitivity and 71.8% specificity. The presence of ≥2 HRFs demonstrated a high sensibility (92.3%) and specificity (71.9%) (P<0.0001).

Conclusions

Detection of HRFs is predictive of relapse with a sensibility that increases with the number of HRFs observed. This observation may allow to better define the diagnostic follow algorithm up suggesting to performing further exams only in patients with >2 HRFs.

Clinical outcomes of CyberKnife stereotactic radiosurgery for elderly patients with presumed primary stage I lung cancer

BACKGROUND

In certain situations, especially in the elderly patient population, a tissue diagnosis of a suspected pulmonary neoplasm is not feasible. Often, a definitive treatment such as stereotactic body radiosurgery is recommended, rather than active surveillance. The aim of this study is to evaluate the efficacy and tolerability of stereotactic body radiotherapy (SBRT) for elderly patients with presumed primary stage I lung cancer without pathological tissue confirmation.

METHODS

We performed a retrospective analysis of 25 elderly patients (≥75 years) with presumed primary stage I lung cancer treated with SBRT from 2009-2015. The primary end point was local control (LC); secondary end points were survival and toxicity.

RESULTS

The median follow-up (FU) was 36.0 months (range, 4 to 84 months). The 1-year LC rate was 100%, 3-year LC rate was 78.8%, and 5-year LC rate was 65.7%. The median progression-free survival (PFS) time was 48.0 months (95% CI: 31.2-64.8). The 1-, 3-, and 5-year overall survival (OS) rates were 96.0%, 70.2%, and 50.7%, respectively. The 1-, 3-, and 5-year cancer-specific survival (CSS) rates were 100%, 81.3%, and 67.0%, respectively. No grade 4 or higher toxicity was encountered.

CONCLUSIONS

SBRT is safe and effective treatment for patients with presumed primary stage I lung cancer where obtaining pathological confirmation of malignancy is challenging.

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.

Clinical outcomes of video-assisted thoracic surgery and stereotactic body radiation therapy for early-stage non-small cell lung cancer: A meta-analysis

Background

We compared video‐assisted thoracoscopic surgery (VATS) lobectomy and stereotactic body radiation therapy (SABR) to explore clinical outcomes in the treatment of patients with early stage NSCLC.

Methods

Major medical databases were systematically searched to identify studies on VATS and SBRT published between January 2010 and October 2015. English publications of stage I and II NSCLC with adequate patients and SBRT doses were included. A multivariate random effects model was used to perform meta‐analysis to compare overall survival (OS) and disease‐free survival (DFS) between VATS and SBRT, adjusting for median age and operable patient numbers.

Results

Thirteen VATS (3436 patients) and 24 SBRT (4433) studies were eligible. The median age and follow‐up duration was 68 years and 42 months for VATS and 74 years and 29.4 months for SBRT patients. After adjusting for the proportion of operable patients and median age, the estimated OS rates at one, two, three, and five years with VATS were 94%, 89%, 84%, and 69% compared with 96%, 94%, 89%, and 82% for SBRT. The estimated DFS rates at one, two, three, and five years with VATS were 97%, 93%, 87%, and 77% compared with 86%, 80%, 73%, and 58% for SBRT.

Conclusion

Before adjustment, patients treated with SBRT had poorer clinical outcomes compared to those treated with VATS. A substantial difference between median age and operability exists between patients treated with SBRT and VATS. After adjusting for these differences, OS and DFS did not differ significantly between the two techniques.

[Comparison of Clinical Outcomes of VATS and SBRT in the Treatment of NSCLC]

BACKGROUND AND OBJECTIVE

More and more chest physicians chose video-assisted thoracoscopic surgery (VATS) to treat early stage non-small cell lung cancer (NSCLC). In recent years, there is still lack of a random trial comparing the clinical outcomes of VATS and stereotactic body radiotherapy (SBRT) in treating NSCLC. To provide a reference for the choice between VATS and SBRT, in the current meta-analysis, we compared the clinical outcomes of these two therapies in treating NSCLC.

METHODS

Five major medical databases, CNKI, CPVIP (http://www.cqvip.com/), PubMed, Embase, and ISI web of science were systematically searched to identify all studies from January 2010 to February 2016 on VATS and SBRT therapies. Finally, original English or Chinese publications of stage I and II NSCLC with adequate patients and adequate SBRT doses were enrolled. A multivariate random effects model was used to perform a meta-analysis to compare overall survival and disease free survival between VATS and SBRT while adjusting for median age and operable patient numbers.

RESULTS

Fourteen VATS studies (included 3,482 patients) and nineteen SBRT studies (included 3,997 patients) published in the same period were eligible. The median age and follow-up duration were 64 years and 43.4 months for VATS patients and 74 years and 29.5 months for SBRT patients, respectively. The mean unadjusted overall survival rates at 1, 2, 3, and 5 years with VATS were 93.5%, 84.9%, 77.0% and 76.3% compared to 89.0% 73.3% 59.0% and 36.7% with SBRT. The mean unadjusted disease free survival rates at 1, 2, 3, and 5 years with VATS were 93.6%, 88.6%, 85.6% and 75.6% compared to 79.3%, 72.1%, 64.9% and 58.9% with SBRT. While, after adjusted for proportion of operable patients and median age, the estimate overall survival rates at 1, 2, 3, and 5 years with VATS were 94%, 92%, 84% and 71% compared to 98%, 95%, 87% and 83% with SBRT. And the estimate disease free survival rates at 1, 2, 3, and 5 years with VATS were 97%, 94%, 85% and 75% compared to 88%, 81%, 74% and 63% with SBRT.

CONCLUSION

Before adjustment, the SBRT group showed worse clinical outcomes (overall survival and disease free survival) than VATS group. When take consider of median age and operability, the patients with SBRT differ substantially from patients treated with VATS. After adjustment of median age and operability, there are no significant differences between these two therapy in treating NSCLC.

Stereotactic body radiotherapy for second pulmonary nodules after operation for an initial lung cancer

OBJECTIVE

A second lung cancer is occasionally observed in patients who underwent surgical resection of the index lung cancer. The purpose of this study is to evaluate stereotactic body radiation therapy for second lung cancer.

METHODS

Fifty-one medically inoperable patients who underwent stereotactic body radiation therapy for second lung cancer were the subjects: 31 cases of multiple primary lung cancer and 20 of pulmonary metastasis from the index cancer. Clinical stage was T1a in 27 patients, T1b in 13 patients and T2a in 11 patients, and 70% of subjects had impaired respiratory function. Histology of second lung cancer was adenocarcinoma in 16 patients, squamous cell carcinoma in 9 patients and not assessed in 25 patients. The interval between index cancer operation and stereotactic body radiation therapy was 31 months (range: 4-171). The total stereotactic body radiation therapy doses were 48 Gy in 4 fractions or 60 Gy in 10 fractions.

RESULTS

With the median follow-up of 36 months, 3-year overall survival rates were 62% with the median survival time of 46 months. Cause-specific survival was 73% at 3 years. Overall survival for multiple primary lung cancer and pulmonary metastasis was quite similar: 62 and 61% at 3 years, respectively. Three-year overall survival was 77% for T1a and 43% for T1b or T2a. Grade 2 pulmonary toxicities occurred in five patients and one patient died of Grade 5 pneumonitis.

CONCLUSIONS

Even though the subjects were medically inoperable, the survival outcomes of stereotactic body radiation therapy were favorable. Furthermore, having acceptable toxicity, stereotactic body radiation therapy is feasible and could be an option for multiple primary lung cancer and pulmonary metastasis after surgical resection for the index cancer.

Particle therapy for clinically diagnosed stage I lung cancer: comparison with pathologically proven non-small cell lung cancer

BACKGROUND

The purpose of the present study was to present the treatment outcomes of particle therapy for indeterminate pulmonary nodules (IPNs) diagnosed as stage I non-small cell lung cancer, including a comparative analysis involving pathologically proven lung cancer (PPLC).

MATERIAL AND METHODS

A total of 54 patients (57 lesions) who underwent particle therapy for IPNs were enrolled in this study. Median patient age was 76 (range 52-87) years. T-classification was: T1a, 30; T1b, 16; and T2a, 11. Particle therapy using protons or carbon ions was delivered at total doses of 52.8-80 Gy equivalent in 4-26 fractions. The PPLC cohort included 111 patients.

RESULTS

The median follow-up time was 41 (range 7-90) months. For all IPN patients, the three-year overall survival, progression-free survival, local control and distant progression-free survival rates were 90%, 72%, 94% and 79%, respectively. Grade 2 toxicities were radiation pneumonitis (19%), dermatitis (9%), rib fracture (2%), chest wall pain (2%) and neuropathy (2%). No ≥grade 3 toxicities were observed. In univariate analysis, the IPN group showed significantly better survival relative to the PPLC group. However, after adjustment for baseline imbalances between these two groups in multivariate analysis, pathological confirmation did not correlate with survival.

CONCLUSIONS

Particle therapy for IPNs provided favorable outcomes with minimal toxicities, which may be comparable to those for PPLC patients. Further studies are needed to clarify the optimal management of IPN patients.

Outcomes of stereotactic body radiotherapy (SBRT) treatment of multiple synchronous and recurrent lung nodules

Background

Stereotactic body radiotherapy (SBRT) is evolving into a standard of care for unresectable lung nodules. Local control has been shown to be in excess of 90% at 3 years. However, some patients present with synchronous lung nodules in the ipsilateral or contralateral lobe or metasynchronous disease. In these cases, patients may receive multiple courses of lung SBRT or a single course for synchronous nodules. The toxicity of such treatment is currently unknown.

Methods

Between 2006 and 2012, 63 subjects with 128 metasynchronous and synchronous lung nodules were treated at the Mayo Clinic with SBRT. Demographic patient data and dosimetric data regarding SBRT treatments were collected. Acute toxicity (defined as toxicity < 90 days) and late toxicity (defined as toxicity > = 90 days) were reported and graded as per standardized CTCAE 4.0 criteria. Local control, progression free survival and overall survival were also described.

Results

The median age of patients treated was 73 years. Sixty five percent were primary or recurrent lung cancers with the remainder metastatic lung nodules of varying histologies. Of 63 patients, 18 had prior high dose external beam radiation to the mediastinum or chest. Dose and fractionation varied but the most common prescriptions were 48 Gy/4 fractions, 54 Gy/3 fractions, and 50 Gy/5 fractions. Only 6 patients demonstrated local recurrence. With a median follow up of 12.6 months, median SBRT specific overall survival and progression free survival were 35.7 months and 10.7 months respectively. Fifty one percent (32/63 patients) experienced acute toxicity, predominantly grade 1 and 2 fatigue. One patient developed acute grade 3 radiation pneumonitis at 75 days. Forty six percent (29/63 patients) developed late effects. Most were grade 1 dyspnea. There was one patient with grade 5 pneumonitis.

Conclusion

Multiple courses of SBRT and SBRT delivery after external beam radiotherapy appear to be feasible and safe. Most toxicity was grade 1 and 2 but the risk was approximately 50% for both acute and late effects.

Characteristics and management strategies for the incidental pulmonary nodule

SUMMARY: 

Pulmonary nodules are frequent, unanticipated findings on imaging studies obtained for other purposes across all areas of medical practice. As nodule detection raises concern for malignancy, evaluation and follow-up of an incidental nodule is imperative. Clinicians are charged with counseling patients and directing further evaluation amid uncertainty and anxiety. The goals of follow-up and management are to identify malignant lesions at an early stage, while avoiding unnecessary procedures and potential harm to patients with benign nodules. In this review, we aim to outline the clinical and radiographic characteristics that can aid in likelihood stratification, to identify gaps in our current knowledge, and to present a logical approach to nodule management, based on the available evidence.

Comparison of outcomes following stereotactic body radiotherapy for non-small cell lung cancer in patients with and without pathological confirmation

PURPOSE/OBJECTIVE

Treatment of presumed early-stage lung cancer with definitive radiation therapy in the absence of a pathologically confirmed specimen frequently occurs. However, it is not well described in the literature, and there are few North American series reporting on this patient population. We report outcomes in patients treated with stereotactic body radiotherapy (SBRT) for presumed lung cancer and compare them to outcomes in patients treated with SBRT with pathologically confirmed non-small cell lung cancer (NSCLC).

MATERIALS/METHODS

This study is based on a retrospective review of 55 patients with presumed or confirmed lung cancer: 23 patients had nondiagnostic or absent pathologic specimens while 32 patients had pathologically confirmed NSCLC. All patients had hypermetabolic primary lesions on a positron emission tomography (PET) or PET/computed tomography (CT) scan. SBRT was delivered as 48-56 Gy in four to five fractions via a four-dimensional CT treatment plan.

RESULTS

Of the patients without pathological confirmation, the mean age was 78 (range 63-89 years) and 17 (74%) were men. The mean tumor size was 2.5 cm (range 1.0-5.1). Reasons for not having confirmed pathologic diagnosis included indeterminate biopsy specimen or an inability to tolerate a biopsy procedure due to poor respiratory status. SBRT was chosen due to noncandidacy for surgery in 17 patients (74%) or patient refusal of surgery in six (26%). Median follow up was 24.2 months (range 1.9-64.6): 2 of the 23 patients (8.7%) had local failure at the site of SBRT and 3 (13%) had regional failure. The actuarial 12-month overall survival was 83%. The median overall survival was 30.2 months. At last follow up, 12 patients (52%) were alive up to 64.6 months after treatment. SBRT was tolerated well in this series. Acute toxicity was noted in two patients (8.7%) and chronic toxicity in three (13%). These patient characteristics and results were shown to be similar to the 32 patients with pathologically confirmed NSCLC. On Kaplan-Meier analysis, there was no significant difference (p = 0.27) in overall survival between patients with pathologically confirmed NSCLC and those with presumed lung cancer (which was deemed most likely NSCLC).

CONCLUSION

While biopsy confirmation remains a goal in the workup of suspected NSCLC, SBRT without pathologic confirmation may represent a safe and effective option for the treatment of presumed NSCLC among patients who cannot tolerate or refuse surgery.

Outcomes and prognostic factors for recurrence after high-dose proton beam therapy for centrally and peripherally located stage I non--small-cell lung cancer

INTRODUCTION

This study was conducted to determine disease control rates and prognostic factors associated with recurrence of centrally and peripherally located stage I NSCLC treated using high-dose PBT.

PATIENTS AND METHODS

Seventy-four patients with 80 centrally or peripherally located stage I NSCLCs were treated with PBT. A protocol using 72.6 Gy (RBE) in 22 fractions was used for centrally located tumors, and 66 Gy (RBE) in 10 or 12 fractions was used for peripherally located tumors. Data were collected and control rates and prognostic factors for recurrence were evaluated retrospectively.

RESULTS

The median follow-up period was 31.0 months. The overall survival, disease-specific survival, and progression-free survival rates were 76.7%, 83.0%, and 58.6% at 3 years, respectively. Disease recurrence was noted in 30 patients and local recurrence of 11 tumors occurred. The 3-year local control rate was 86.2% for stage IA tumors and 67.0% for stage IB tumors. Radiation dose was identified as a significant prognostic factor for disease recurrence and local recurrence. Tumor diameter and age were only significantly associated with disease recurrence. The 3-year local control rate was 63.9% for centrally located tumors irradiated with 72.6 Gy (RBE) and 88.4% for peripherally located tumors irradiated with 66 Gy (RBE).

CONCLUSION

Radiation dose was shown to be the most significant prognostic factor for tumor control in stage I NSCLC treated using high-dose PBT. Tumor diameter was not significant for local control. Further evaluation of PBT for centrally located tumors is warranted.

Stereotactic body radiation therapy in octogenarians with stage I lung cancer

BACKGROUND

The purpose of this study was to describe our clinical experience using stereotactic body radiation therapy (SBRT) to treat medically inoperable stage I non-small-cell lung cancer (NSCLC) in very elderly patients.

PATIENTS AND METHODS

Twenty-four consecutive octogenarians with stage I NSCLC were treated with SBRT between 2007 and 2011 at a single center. Median prescription dose was 48 Gy (range, 48-56). Follow-up clinical examination and computed tomography (CT) were performed every 2 to 3 months.

RESULTS

Median age was 85 years (range, 80-89). Twenty-three (96%) patients had peripheral tumors, and median tumor size was 22 mm (range, 11-49). Tissue diagnosis was obtained in 16 (67%) patients. Median follow-up for all patients was 27.6 months (range, 4.3-61.2). The 24-month disease-free survival was 77% (95% confidence interval [CI], 61%-97%). The 24-month overall survival (OS) was 74% (95% CI, 57%-94%). No local failure (LF) was observed during the period of observation. Nodal failure (NF) and distant failure (DF) occurred in 2 and 4 patients, respectively. The cumulative incidence of competing mortality at 24 months was estimated at 13% (95% CI, 3%-30%). No difference in outcomes with or without tissue diagnosis was observed. No grade ≥ 3 early or late treatment-related toxicities were observed.

CONCLUSION

Octogenarians tolerate SBRT well, which makes it an attractive treatment option.

Stereotactic radiotherapy (SABR) for the treatment of primary non-small cell lung cancer; systematic review and comparison with a surgical cohort

BACKGROUND AND PURPOSE

To assess the efficacy of stereotactic ablative radiotherapy (SABR) for the treatment of non-small cell lung cancer (NSCLC) through a systematic review of all relevant publications from 2006 to the present compared to controls treated with surgery. In the absence of Grade I evidence, the objective outcome data should form the basis for planning future studies and commissioning SABR services.

MATERIALS AND METHODS

Standard systematic review methodology extracting patient and disease characteristics, treatment and outcome data from published articles reporting patient data from populations of 20 or more Stage I NSCLC patients treated with SABR with a median follow up of minimum of 1 year. The individual outcome measures were corrected for stage and summary weighted outcome data were compared to outcome data from a large International Association for the Study of Lung Cancer (IASLC) cohort matched for stage of disease with survival as the principal endpoint and local control (local progression free survival - local PFS) as the secondary endpoint.

RESULTS

Forty-five reports containing 3771 patients treated with SABR for NSCLC were identified that fulfilled the selection criteria; both survival and staging data were reported in 3171 patients. The 2 year survival of the 3201 patients with localized stage I NSCLC treated with SABR was 70% (95% CI: 67-72%) with a 2 year local control of 91% (95% CI: 90-93%). This was compared to a 68% (95% CI: 66-70) 2 year survival of 2038 stage I patients treated with surgery. There was no survival or local PFS difference with different radiotherapy technologies used for SABR.

CONCLUSIONS

Systematic review of a large cohort of patients with stage I NSCLC treated with SABR suggests that survival outcome in the short and medium term is equivalent to surgery for this population of patients regardless of co-morbidity. As selection bias cannot be assessed from the published reports and treatment related morbidity data are limited, a direct comparison between the two treatment approaches should be a priority. In the meantime, SABR can be offered to stage I patients with NSCLC as an alternative to surgery.

Use of PET/CT for patient selection and radiation therapy target volume definition in patients with non-small-cell lung cancer

SUMMARY PET scanning is having an increasing impact on the treatment of non-small-cell lung cancer with radiation therapy (RT) and chemoRT. It has a powerful impact on staging, often revealing evidence of more advanced, frequently incurable, disease in patients who would otherwise be considered suitable for treatment with potentially curative definitive RT. Approximately a third of curative RT candidates are found to be unsuitable for this often highly toxic form of treatment after PET, thereby ensuring that this intensive treatment is only given to those patients who might benefit from it. If a patient remains suitable for treatment with RT after PET staging, PET can play a further critical role in the targeting of the RT. Without the use of PET in this way, a quarter of patients or more would experience geographic misses, in which some tumor regions would be either underdosed or excluded entirely from treatment, thereby compromising the chances of a successful outcome. There is emerging evidence that the overall results of treatment with RT can be improved by the appropriate use of PET in non-small-cell lung cancer.

Is stereotactic ablative radiotherapy an alternative to surgery in operable stage I non-small cell lung cancer?

Surgery is the gold therapeutic standard for patients affected with stage I non-small cell lung cancer. Stereotactic ablative radiotherapy is currently considered the preferred treatment option for inoperable patients, representing approximately 25%. Limited data are available directly comparing surgery and SABR in operable patients, none of them prospective. Preliminary results are encouraging, showing that the two treatment modalities are equally effective in terms of tumour control, with expected similar survival projections. Moreover, in elderly patients SABR could represent a valid treatment alternative in comparison to surgery due to the lower morbidity. We here review and discuss the potential role of SABR as an alternative to surgery in operable early stage lung cancer patients.

Evaluation for local failure by 18F-FDG PET/CT in comparison with CT findings after stereotactic body radiotherapy (SBRT) for localized non-small-cell lung cancer

PURPOSE

Stereotactic body radiotherapy (SBRT) is the standard care for medically inoperable early non-small-cell lung cancer (NSCLC). However, it can be difficult to differentiate local recurrence from non-recurrence radiation-induced lung opacity. We retrospectively assessed (18)F-FDG PET/CT to detect local recurrence after SBRT for NSCLC.

METHODS

Between 2005 and 2011, 273 NSCLCs in 257 patients were treated with SBRT. Prescribed doses were 50Gy and 40Gy per 5 fractions for peripheral and central lesions, respectively. Tri-monthly follow-up CT scans were acquired. (18)F-FDG PET/CT scans were scheduled for screening at one year after SBRT or when recurrence was highly suspected. The dual-time-point maximum standardized uptake values (SUVmaxs) and their retention indexes (RIs) were obtained.

RESULTS

A total of 214 (18)F-FDG PET/CT scans were obtained for 164 localized NSCLC tumors in 154 patients. The median follow-up period was 24.9 months (range: 6.3-72.1). Among these, 21 scans of 17 tumors were diagnosed as local recurrence. The median SUVmaxs on early and late images of recurrence and their RI were 5.0 (range: 3.2-10.7), 6.3 (range: 4.2-13.4), and 0.20 (range; 0-0.41), respectively. These were significantly higher than the respective values of non-recurrence images of 1.8 (range: 0.5-4.6), 1.7 (range: 0.5-6.1), and 0.00 (range: -0.37-0.41) (all p<0.05). For SUVmaxs on early and late images, optimal thresholds were identified as 3.2 and 4.2. Using each threshold, the sensitivity and specificity were 100% and 96-98%, respectively. CT findings were classified into ground-glass opacity (N=9), scar or fibrotic change (N=96), consolidation with air-bronchogram (N=34), consolidation only (N=22), and nodule (N=17); the respective numbers of recurrence were 0, 0, 1, 3, and 17.

CONCLUSION

SUVmaxs of (18)F-FDG PET/CT could detect local recurrence after SBRT for localized NSCLC. In contrast, CT scan results had a limited ability to diagnose local recurrence.