Effectiveness of radiation therapy for elderly patients with unresected stage I and II non-small cell lung cancer

Surgery or radiotherapy improves survival in elderly patients with early non-small cell lung cancer: A population-based analysis

OBJECTIVE

There is a lack of evidence to support a consensus on whether surgery or radiotherapy is optimal for elderly or very elderly patients with early-stage non-small cell lung cancer (NSCLC). We aimed to assess the impact of surgery or radiotherapy on survival in elderly (≥70 years) and very elderly (≥80 years) patients with early-stage NSCLC.

METHODS

Patients aged ≥70 years diagnosed with early-stage NSCLC between January 1, 1975, and December 31, 2018, were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Overall survival (OS) and cancer-specific survival (CSS) were assessed based on surgery, radiotherapy, and no-treatment groups.

RESULTS

Data for 15,224 NSCLC patients aged ≥70 years were collected, which consisted of 6949 (45.6%) patients who underwent surgery alone, 5014 (32.9%) who underwent radiotherapy alone, and 3261 (21.5%) who received no treatment. Surgery significantly improved patient survival compared with no treatment (MST: 74 months vs. 7 months, HR: 0.201, 95% CI: 0.186-0.217, P < 0.001), as did radiotherapy (MST: 28 months vs. 7 months, HR: 0.440; 95% CI: 0.413-0.469, P < 0.001). Surgery also resulted in improved survival compared with radiotherapy (74 months vs. 28 months, HR: 0.455; 95% CI: 0.430-0.482, P < 0.001). A similar conclusion was made from the analysis of CSS. A subgroup analysis further confirmed the survival benefits.

CONCLUSIONS

The results of this large-scale retrospective study indicate that both surgery and radiotherapy significantly enhance survival outcomes in patients aged ≥70 or ≥80 years with early-stage NSCLC. The survival benefits of surgery were particularly notable.

Quantification of diffuse parenchymal lung disease in non-small cell lung cancer patients with definitive concurrent chemoradiation therapy for predicting radiation pneumonitis

BACKGROUND

We sought to quantify diffuse parenchymal lung disease (DPLD) extent using quantitative computed tomography (CT) analysis and to investigate its association with radiation pneumonitis (RP) development in non-small cell lung cancer (NSCLC) patients receiving definitive concurrent chemoradiation therapy (CCRT).

METHODS

A total of 82 NSCLC patients undergoing definitive CCRT were included in this prospective cohort study. Pretreatment CT scans were analyzed using quantitative CT analysis software. Low-attenuation area (LAA) features based on lung density and texture features reflecting interstitial lung disease (ILD) were extracted from the whole lung. Clinical and dosimetric factors were also evaluated. RP development was assessed using the Common Terminology Criteria for Adverse Events version 5.0. Univariable and multivariable logistic regression analyses were performed to identify independent risk factors for grade ≥3 (≥GR3) RP.

RESULTS

RP was identified in 68 patients (73.9%), with nine patients (10.9%) experiencing ≥GR3 RP. Univariable logistic regression analysis identified excess kurtosis and high-attenuation area (HAA)_volume (cc) as significantly associated with ≥GR3 RP. Multivariable logistic regression analysis showed that the combined use of imaging features and clinical factors (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], and CHEMO regimen) demonstrated the best performance (area under the receiver operating characteristic curve = 0.924) in predicting ≥GR3 RP.

CONCLUSION

Quantified imaging features of DPLD obtained from pretreatment CT scans would predict the occurrence of RP in NSCLC patients undergoing definitive CCRT. Combining imaging features with clinical factors could improve the accuracy of the predictive model for severe RP.

Treatment and mortality risk of older adults with non-small cell cancer in Taiwan: A population-based cohort study

BACKGROUND

Older patients tend to have decreased physical functions and more comorbidities than younger patients. At present, the best management for very elderly patients with lung cancer is not known. In this study, we aimed to investigate treatment and mortality risk of older adults with non-small cell cancer (NSCLC) in Taiwan.

METHODS

This study analyzed data from the Taiwan Cancer Registry database. Patients aged ≥80 years with newly diagnosed NSCLC between 2010 and 2017 were included. Treatment options were categorized as curative, palliative, and no treatment. Patients were followed up until death or December 31, 2020. Univariable and multivariable Cox proportional hazards models were used to estimate mortality risk, and Kaplan-Meier survival curves were drawn.

RESULTS

A total of 11 941 patients, aged ≥80 years, with newly diagnosed NSCLC between 2010 and 2017 were identified from the Taiwan Cancer Registry and followed up until 2020. The mean age was 84.4 ± 3.7 years old, and 7468 (62.54%) were men. The Kaplan-Meier survival curves showed significant differences across the three treatment options (log-rank p < 0.001). Results from multivariate Cox regression demonstrated that patients on palliative treatment (adjusted HR: 0.52, 95% CI: 0.48-0.56, p < 0.001) and curative treatment (adjusted HR: 0.45, 95% CI: 0.42-0.48, p < 0.001) had a significantly lower mortality risk than those with no treatment. The subgroup analyses stratified by cancer stages also showed consistent findings.

CONCLUSION

Elderly patients with NSCLC had significantly decreased mortality risk when receiving curative or palliative treatment compared with those without treatment. In the future, further studies are warranted to investigate complications and quality of life of elderly patients with NSCLC during palliative or curative treatment.

Impact of diabetes on stage I lung cancer treatment patterns and prognosis in older adults: A population-based cohort study

Background

Diabetes is a common comorbidity in patients with early-stage non-small cell lung cancer (NSCLC), a growing population due to increased LC screening. However, it is unknown if diabetes is associated with less aggressive NSCLC treatment and worse NSCLC outcomes. This study aimed to investigate treatment patterns and outcomes of older patients with Stage I NSCLC and diabetes.

Methods

Using national cancer registry data linked to Medicare, we identified patients ≥65 years old with Stage I NSCLC. Patients were categorized as having no diabetes, diabetes without severe complications (DM-c), or diabetes with ≥1 severe complication (DM + c). We used multinomial logistic regression to assess the association of diabetes and NSCLC treatment. The association of diabetes category with NSCLC and non-NSCLC survival was analyzed with Fine-Grey competing-risks regression.

Results

In 25,358 patients (75% no diabetes, 12% DM-c and 13% had DM + c), adjusted analyses showed that DM-c and DM + c were associated with increased odds of receiving limited resection rather than lobectomy (odds ratio [OR]: 1.22, 95% confidence interval [CI]: 1.07-1.37 and OR 1.42, 95% CI 1.26-1.59, respectively). Competing risk regression showed diabetes was associated with increased risk of non-NSCLC death (DM-c hazard ratio [HR] 1.16, 95% CI: 1.08-1.25, DM + c HR 1.49, 95% CI: 1.40-1.59), but not NSCLC-specific death.

Conclusion

This study uncovers critical information on how diabetes is associated with less aggressive early-stage NSCLC care in older patients. This study also confirms that diabetes increases death from non-lung cancer causes and managing comorbidities is crucial to improving outcomes in older early-stage NSCLC survivors.

Real-World Impact of SABR on Stage I Non-Small-Cell Lung Cancer Outcomes at a Scottish Cancer Centre

INTRODUCTION

Stereotactic ablative body radiotherapy (SABR) offers patients with stage I non-small-cell lung cancer (NSCLC) a safe, effective radical therapy option. The impact of introducing SABR at a Scottish regional cancer centre was studied.

METHODS

The Edinburgh Cancer Centre Lung Cancer Database was assessed. Treatment patterns and outcomes were compared across treatment groups (no radical therapy (NRT), conventional radical radiotherapy (CRRT), SABR and surgery) and across three time periods reflecting the availability of SABR (A, January 2012/2013 (pre-SABR); B, 2014/2016 (introduction of SABR); C, 2017/2019, (SABR established)).

RESULTS

1143 patients with stage I NSCLC were identified. Treatment was NRT in 361 (32%), CRRT in 182 (16%), SABR in 132 (12%) and surgery in 468 (41%) patients. Age, performance status, and comorbidities correlated with treatment choice. The median survival increased from 32.5 months in time period A to 38.8 months in period B to 48.8 months in time period C. The greatest improvement in survival was seen in patients treated with surgery between time periods A and C (HR 0.69 (95% CI 0.56-0.86), p < 0.001). The proportion of patients receiving a radical therapy rose between time periods A and C in younger (age ≤ 65, 65-74 and 75-84 years), fitter (PS 0 and 1), and less comorbid patients (CCI 0 and 1-2), but fell in other patient groups.

CONCLUSIONS

The introduction and establishment of SABR for stage I NSCLC has improved survival outcomes in Southeast Scotland. Increasing SABR utilisation appears to have enhanced the selection of surgical patients and increased the proportion of patients receiving a radical therapy.

Medical management of older patients with lung cancer

Lung cancer is the most common cause of cancer-related death globally. In addition, its incidence increases with age, with approximately half of all cases diagnosed in patients aged ≥70. Molecular targeted therapies and immunotherapies for advanced non-small-cell lung cancer have markedly improved outcomes over the past two decades. Despite the high incidence of lung cancer in older people, most trials excluded such patients from enrollment. Therefore, the optimal treatment strategies for older patients remain unclear. The present review summarizes the published literature and provides guidance on the treatment of older patients with lung cancer within three broad stages: (i) early-stage lung cancer, (ii) locally advanced lung cancer and (iii) metastatic lung cancer. We also discuss the use of the latest evidence for older patients.

Strengths and limitations of large databases in lung cancer radiation oncology research

There has been a substantial rise in the utilization of large databases in radiation oncology research. The advantages of these datasets include a large sample size and inclusion of a diverse population of patients in a real-world setting. Such observational studies hold promise in enhancing our understanding of questions for which evidence is conflicting or absent in lung cancer radiotherapy. However, it is critical that investigators understand the strengths and limitations of large databases in order to avoid the common pitfalls that beset observational analyses. This review begins by outlining the data variables available in major registries that are used most often in observational analyses. This is followed by a discussion of the type of radiotherapy-related questions that can be addressed using such datasets, accompanied by examples from the lung cancer literature. Finally, we describe some limitations of observational research and techniques to mitigate bias and confounding. We hope that clinicians and researchers find this review helpful for designing new research studies and interpreting published analyses in the literature.

Surgery or radiotherapy for stage I lung cancer? An intention-to-treat analysis

INTRODUCTION

Surgery is the standard of care for early-stage lung cancer, with stereotactic ablative body radiotherapy (SABR) a lower morbidity alternative for patients with limited physiological reserve. Comparisons of outcomes between these treatment options are limited by competing comorbidities and differences in pre-treatment pathological information. This study aims to address these issues by assessing both overall and cancer-specific survival for presumed stage I lung cancer on an intention-to-treat basis.

METHODS

This retrospective intention-to-treat analysis identified all patients treated for presumed stage I lung cancer within a single large UK centre. Overall survival, cancer-specific survival, and combined cancer and treatment-related survival were assessed with adjustment for confounding variables using Cox proportional hazards and Fine-Gray competing risks analyses.

RESULTS

468 patients (including 316 surgery and 99 SABR) were included in the study population. Compared with surgery, SABR was associated with inferior overall survival on multivariable Cox modelling (SABR HR 1.84 (95% CI 1.32-2.57)), but there was no difference in cancer-specific survival (SABR HR 1.47 (95% CI 0.80-2.69)) or combined cancer and treatment-related survival (SABR HR 1.27 (95% CI 0.74-2.17)). Combined cancer and treatment-related death was no different between SABR and surgery on Fine-Gray competing risks multivariable modelling (subdistribution hazard 1.03 (95% CI 0.59-1.81)). Non-cancer-related death was significantly higher in SABR than surgery (subdistribution hazard 2.16 (95% CI 1.41-3.32)).

CONCLUSION

In this analysis, no difference in cancer-specific survival was observed between SABR and surgery. Further work is needed to define predictors of outcome and help inform treatment decisions.

A systematic review of instrumental variable analyses using geographic region as an instrument

BACKGROUND

Instrumental variables analysis is a methodology to mitigate the effects of measured and unmeasured confounding in observational studies of treatment effects. Geographic area is increasingly used as an instrument.

METHODS

We conducted a literature review to determine the properties of geographic area in studies of cancer treatments. We identified cancer studies performed in the United States which incorporated instrumental variable analysis with area-wide treatment rate within a geographic region as the instrument. We assessed the degree of treatment variability between geographic regions, assessed balance of measured confounders afforded by geographic area and compared the results of instrumental variable analysis to those of multivariable methods.

RESULTS

Geographic region as an instrument was relatively common, with 22 eligible studies identified, many of which were published in high-impact journals. Treatment rates did not vary greatly by geographic region. Covariates were not balanced by the instrument in the majority of studies. Eight out of eleven studies found statistically significant effects of treatment on multivariable analysis but not for instrumental variables, with the central estimates of the instrumental variables analysis generally being closer to the null.

CONCLUSIONS

We recommend caution and an investigation of IV assumptions when considering the use of geographic region as an instrument in observational studies of cancer treatments. The value of geographic region as an instrument should be critically evaluated in other areas of medicine.

Thoracic radiation-induced pleural effusion and risk factors in patients with lung cancer

The risk factors and potential practice implications of radiation-induced pleural effusion (RIPE) are undefined. This study examined lung cancer patients treated with thoracic radiation therapy (TRT) having follow-up computed tomography (CT) or 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT. Increased volumes of pleural effusion after TRT without evidence of tumor progression was considered RIPE. Parameters of lung dose-volume histogram including percent volumes irradiated with 5-55 Gy (V5-V55) and mean lung dose (MLD) were analyzed by receiver operating characteristic analysis. Clinical and treatment-related risk factors were detected by univariate and multivariate analyses. 175 out of 806 patients receiving TRT with post-treatment imaging were included. 51 patients (24.9%) developed RIPE; 40 had symptomatic RIPE including chest pain (47.1%), cough (23.5%) and dyspnea (35.3%). Female (OR = 0.380, 95% CI: 0.156-0.926, p = 0.033) and Caucasian race (OR = 3.519, 95% CI: 1.327-9.336, p = 0.011) were significantly associated with lower risk of RIPE. Stage and concurrent chemotherapy had borderline significance (OR = 1.665, p = 0.069 and OR = 2.580, p = 0.080, respectively) for RIPE. Patients with RIPE had significantly higher whole lung V5-V40, V50 and MLD. V5 remained as a significant predictive factor for RIPE and symptomatic RIPE (p = 0.007 and 0.022) after adjusting for race, gender and histology. To include, the incidence of RIPE is notable. Whole lung V5 appeared to be the most significant independent risk factor for symptomatic RIPE.

Disparities in treatment of patients with inoperable stage I non-small cell lung cancer: a population-based analysis

BACKGROUND

Patients unable to receive surgery for stage I non-small cell lung cancer (NSCLC) can undergo conventional radiotherapy (ConvRT), stereotactic body radiotherapy (SBRT), or no treatment (NoTx). This study assessed patterns of care and disparities in the receipt of each of these treatments.

METHODS

The study included patients in the National Cancer Database from 2003 to 2011 with T1-T2N0M0 inoperable lung cancer (n = 39,822). Logistic regressions were performed to determine predictors of receiving any radiation versus NoTx and for receiving SBRT versus ConvRT.

RESULTS

Treatment with radiation was significantly less likely in blacks (odds ratio, OR 0.65) and Hispanics (OR 0.42) compared with whites. Treatment with SBRT versus ConvRT was more likely in an academic research program (OR 2.62) and a high-volume facility (OR 7.00) compared with community cancer programs or low-volume facilities. In 2011, use of SBRT, ConvRT, and NoTx was 25%, 28%, and 46% for patients in a community cancer center versus 68%, 11%, and 21%, respectively, in an academic center (p < 0.0001).

CONCLUSION

There were marked institutional and socioeconomic variations in the treatment of inoperable stage I NSCLC. These results suggest that removal of barriers to receive radiation therapy and particularly improved access to SBRT may meaningfully improve survival in this disease.

Three-dimensional conformal radiotherapy by delineations on CT-based simulation in different respiratory phases for the treatment of senile patients with non-small cell lung cancer

AIM

This study aimed to evaluate the application of three-dimensional conformal radiotherapy (3D-CRT) for elderly patients with non-small cell lung cancer (NSCLC) based on computed tomography (CT) simulations in different respiratory phases.

METHODS

A total of 64 patients aged >70 years old with NSCLC were treated by 3D-CRT using CT images in different respiratory phases. The gross tumor volumes (GTVs) at the end of inspiration and end of expiration were combined to obtain the total GTV, which was close to the motional range of tumors during respiration, and no additional expansion of the clinical target volume (CTAV) to planning target volume (PTV) (CTAV:PTV) was included during the recording of respiratory movements. Patients were also planned according to the classic 3D-CRT approach. Efficacy, prognostic factors, and side effects were evaluated.

RESULTS

Compared with the classic approach, the average PTV was 18.9% lower (median: 17.3%), and the average lung volume receiving a prescribed dose for a tumor was 22.4% lower (median: 20.9%). The 1-, 2-, and 3-year survival rates were 70.6%, 54.9%, and 29.4%, respectively, with an overall tumor response rate of 79.7%. The Karnofsky performance status and N stage were independent prognostic factors, whereas age was not.

CONCLUSION

Without affecting therapeutic effects, CT simulations in different respiratory phases were well-tolerated in elderly patients with NSCLC, could effectively reduce PTV, and could improve the quality of life.

The role of stereotactic body radiation therapy (SBRT) in the treatment of oligometastatic disease in the elderly

OBJECTIVE

To report about clinical outcome of stereotactic body radiation therapy (SBRT) in the treatment of oligometastatic disease in elderly patients.

METHODS

Patients with 1-4 inoperable metastases were treated with SBRT. Dose prescription ranged from 40 to 75 Gy in 3-8 fractions. SBRT was delivered using the volumetric modulated arc therapy technique with flattening filter-free photon beams. The primary end points were in-field local control (LC) and toxicity. Secondary end points were overall survival (OS) and disease-specific survival (DSS).

RESULTS

82 patients with 111 total metastases were treated. Median age was 79 years. 64 patients (78%) had a single lesion; the remaining patients had 2-4 lesions. 16 (14.4%) lesions were localized in the abdomen, 50 (45.0%) in the liver and 45 (40.5%) in the lungs. Local response was observed for 87 lesions (78.4%) while local progression was observed in 24 lesions (21.6%). Actuarial 1-year LC was 86.8% ± 3.3%. Actuarial 1-year OS was 93.6% ± 2.7%. 2-year findings were 76.3% ± 4.4% and 72.0% ± 5.6%, respectively. Actuarial 1- and 2-year DSS results were 97.5% ± 2.0% and 81.6% ± 4.9%, respectively. Treatment-related Grade 2-3 toxicity was observed in five patients (4.2%); Grade 1 toxicity in seven patients (5.9%) and no toxicity was observed in 85.4% of the cases.

CONCLUSION

SBRT is a safe and effective therapeutic option for the treatment of oligometastatic disease in the elderly with acceptable rates of LC and low treatment-related toxicity.

ADVANCES IN KNOWLEDGE

The use of SBRT for oligometastatic disease in the elderly can be considered as a valuable approach, particularly for patients with fragile status or refusing other approaches.

Performing both propensity score and instrumental variable analyses in observational studies often leads to discrepant results: a systematic review

OBJECTIVES

Propensity score (PS) and instrumental variable (IV) are analytical techniques used to adjust for confounding in observational research. More and more, they seem to be used simultaneously in studies evaluating health interventions. The present review aimed to analyze the agreement between PS and IV results in medical research published to date.

STUDY DESIGN AND SETTING

Review of all published observational studies that evaluated a clinical intervention using simultaneously PS and IV analyses, as identified in MEDLINE and Web of Science.

RESULTS

Thirty-seven studies, most of them published during the previous 5 years, reported 55 comparisons between results from PS and IV analyses. There was a slight/fair agreement between the methods [Cohen's kappa coefficient = 0.21 (95% confidence interval: 0.00, 0.41)]. In 23 cases (42%), results were nonsignificant for one method and significant for the other, and IV analysis results were nonsignificant in most situations (87%).

CONCLUSION

Discrepancies are frequent between PS and IV analyses and can be interpreted in various ways. This suggests that researchers should carefully consider their analytical choices, and readers should be cautious when interpreting results, until further studies clarify the respective roles of the two methods in observational comparative effectiveness research.

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.

International patterns of radiotherapy practice for non-small cell lung cancer

Radiotherapy is an important treatment modality for non-small cell lung cancer (NSCLC). There are models of radiotherapy utilization that estimate the proportion of patients with NSCLC who have an evidence-based indication for radiotherapy. These estimates range from 46%-68% for radiotherapy utilization at diagnosis and 64%-75% overall. However, actual radiotherapy utilization throughout much of the world is lower than this, ranging from 28%-53%, with the largest differences between actual and estimated radiotherapy utilization seen in stage III NSCLC. Some of this discrepancy is attributable to the assumptions in the models that are based on broad factors such as stage and performance status. Characteristics of the population with underlying lung cancer that often has comorbidities or compromised respiratory function also influence the ability to deliver radiotherapy safely. Sociodemographic factors such as race and income have been found to affect access to radiotherapy in certain jurisdictions. The type of clinician or medical setting the patient presents to initially can also influence radiotherapy use in NSCLC. Potential solutions to improve appropriate radiotherapy utilization for NSCLC include restructuring models of care to ensure that all patients with lung cancer are managed within a multidisciplinary team including a radiation oncologist.

A review of the management of elderly patients with non-small-cell lung cancer

Most patients with non-small-cell lung cancer (NSCLC) are elderly but evidence to guide appropriate treatment decisions for this age group is generally scant. Careful evaluation of the elderly should be undertaken to ensure that treatment appropriate for the stage of the tumour is guided by patient characteristics and not by age. The Comprehensive Geriatric Assessment (CGA) remains the preferred option, but briefer tools may be appropriate to select patients for further evaluation. The predicted outcome should be used to guide management decisions together with a reappraisal of polypharmacy. Patient expectations should also be taken into account. Management recommendations are generally similar to those of general guidelines for the NSCLC population, although the risks of surgery and toxicity of chemotherapy and radiotherapy are often increased in the elderly compared with younger patients; therefore, patients should be closely scrutinised and subjected to a CGA to ensure suitability of the planned treatment. If surgery is indicated, then lobectomy is generally the preferred option, although limited resection may be more feasible for some. Radiotherapy with curative intent is an alternative, with stereotactic body radiotherapy the most likely preferred modality. Adjuvant chemotherapy is also an appropriate approach, whereas adjuvant radiotherapy is generally not recommended. Concurrent chemoradiotherapy should be considered for elderly patients with inoperable locally advanced disease and chemotherapy for advanced/metastatic disease. Efforts should also be made to increase participation of elderly patients with NSCLC in clinical trials, thereby enhancing evidence-based treatment decisions for this majority group. This will require overcoming barriers relating to trial design and to physician and patient awareness and attitudes.

Management of elderly patients with NSCLC; updated expert's opinion paper: EORTC Elderly Task Force, Lung Cancer Group and International Society for Geriatric Oncology

Non-small-cell lung cancer (NSCLC) is a very common disease in the elderly population and its incidence in this particular population is expected to increase further, because of the ageing of the Western population. Despite this, limited data are available for the treatment of these patients and, therefore, the development of evidence-based treatment recommendations is challenging. In 2010, European Organization for Research and Treatment of Cancer (EORTC) took an initiative in collaboration with International Society of Geriatric Oncology (SIOG) and created an experts panel that provided an experts' opinion consensus paper for the management of elderly NSCLC patients. Since this publication, important new data are available and EORTC and SIOG recommended to update the 2010 recommendations. Besides recommendations for surgery, adjuvant chemotherapy and radiotherapy, treatment of locally advanced and metastatic disease, recommendations were expanded, to include data on patient preferences and geriatric assessment.

[Stereotactic ablative irradiation for lung cancer]

Stereotactic radiotherapy for lung cancer is a technique that is now well established in the therapeutic arsenal. Protocols are effective, with very high local control rate and an acceptable rate of survival if one takes into account the patient's age and comorbidities. Complications are rare. This review of the literature analyses the whole process of the therapeutic indications and future prospects.

Introduction to propensity scores

Although randomization provides a gold-standard method of assessing causal relationships, it is not always possible to randomly allocate exposures. Where exposures are not randomized, estimating exposure effects is complicated by confounding. The traditional approach to dealing with confounding is to adjust for measured confounding variables within a regression model for the outcome variable. An alternative approach--propensity scoring--instead fits a regression model to the exposure variable. For a binary exposure, the propensity score is the probability of being exposed, given the measured confounders. These scores can be estimated from the data, for example by fitting a logistic regression model for the exposure including the confounders as explanatory variables and obtaining the estimated propensity scores from the predicted exposure probabilities from this model. These estimated propensity scores can then be used in various ways-matching, stratification, covariate-adjustment or inverse-probability weighting-to obtain estimates of the exposure effect. In this paper, we provide an introduction to propensity score methodology and review its use within respiratory health research. We illustrate propensity score methods by investigating the research question: 'Does personal smoking affect the risk of subsequent asthma?' using data taken from the Tasmanian Longitudinal Health Study.

Stereotactic radiotherapy for pulmonary metastases

The most common treatment of pulmonary metastasis for solid tumors employs systemic chemotherapy, hormonal therapy, or biologic agents. Some series have suggested that aggressive surgical resection of pulmonary metastasis may improve patient outcomes in terms of quality of life and overall survival. Recently, data from clinical trials and retrospective series support the use of aggressive local control with high conformal dose radiotherapy (stereotactic body radiation therapy) in patients with limited metastases or oligometastases. Further evidence suggests that these patients represent a distinct clinical and biological class of patients. This review focuses on the role of ablative doses of radiotherapy in the treatment of pulmonary metastases. Specifically we discuss the rationale, treatment delivery, and local control that have led to the ongoing randomized clinical trials attempting to demonstrate a benefit over the current palliative standard of care.

Microsimulation model predicts survival benefit of radiofrequency ablation and stereotactic body radiotherapy versus radiotherapy for treating inoperable stage I non-small cell lung cancer

OBJECTIVE

A subset of patients with stage IA and IB non-small cell lung cancer (NSCLC) is ineligible for surgical resection and undergoes radiation therapy. Radiofrequency ablation (RFA) and stereotactic body radiotherapy are newer potentially attractive alternative therapies.

MATERIALS AND METHODS

We added RFA and stereotactic body radiotherapy treatment modules to a microsimulation model that simulates lung cancer's natural history, detection, and treatment. Natural history parameters were previously estimated via calibration against tumor registry data and cohort studies; the model was validated with screening study and cohort data. RFA model parameters were calibrated against 2-year survival from the Radiofrequency Ablation of Pulmonary Tumor Response Evaluation (RAPTURE) study, and stereotactic body radiotherapy model parameters were calibrated against 3-year survival from a phase 2 prospective trial. We simulated lifetime histories of identical patients with early-stage NSCLC who were ineligible for resection, who were treated with radiation therapy, RFA, or stereotactic body radiotherapy under a range of scenarios. From 5,000,000 simulated individuals, we selected a cohort of patients with stage I medically inoperable cancer for analysis (n = 2056 per treatment scenario). Main outcomes were life expectancy gains.

RESULTS

RFA or stereotactic body radiotherapy treatment in patients with peripheral stage IA or IB NSCLC who were nonoperative candidates resulted in life expectancy gains of 1.71 and 1.46 life-years, respectively, compared with universal radiation therapy. A strategy where patients with central tumors underwent stereotactic body radiotherapy and those with peripheral tumors underwent RFA resulted in a gain of 2.02 life-years compared with universal radiation therapy. Findings were robust with respect to changes in model parameters.

CONCLUSION

Microsimulation modeling results suggest that RFA and stereotactic body radiotherapy could provide life expectancy gains to patients with stage IA or IB NSCLC who are ineligible for resection.

Developments in early-stage NSCLC: advances in radiotherapy

An increase in the number of predominantly elderly patients with early-stage non-small-cell lung cancer is anticipated in many Western populations. Patients often have major co-morbidities and are at increased risk for surgical morbidity and mortality. In the past decade, the use of stereotactic ablative radiotherapy (SABR) has achieved excellent results, with only mild toxicity in such vulnerable patient groups, leading to SABR becoming accepted as a standard of care for unfit patients in several countries. The planning and delivery of SABR has rapidly improved in recent years, particularly with the use of 'on-board' imaging at treatment units, and shortened treatment delivery times. Increasingly, more central tumors are being treated using lower doses per fraction (so-called risk-adapted schemes). It is also becoming clear that long-term follow-up should take place at specialist centers in order to distinguish the evolving fibrosis that is frequently observed from the relatively infrequent local recurrences. Given the high local control rates and limited toxicity, increasing attention is being paid to the use of SABR in the subgroup of so-called borderline operable patients, and clinical trials comparing surgery and SABR in these patients are ongoing.

Methods in comparative effectiveness research

Comparative effectiveness research (CER) seeks to assist consumers, clinicians, purchasers, and policy makers to make informed decisions to improve health care at both the individual and population levels. CER includes evidence generation and evidence synthesis. Randomized controlled trials are central to CER because of the lack of selection bias, with the recent development of adaptive and pragmatic trials increasing their relevance to real-world decision making. Observational studies comprise a growing proportion of CER because of their efficiency, generalizability to clinical practice, and ability to examine differences in effectiveness across patient subgroups. Concerns about selection bias in observational studies can be mitigated by measuring potential confounders and analytic approaches, including multivariable regression, propensity score analysis, and instrumental variable analysis. Evidence synthesis methods include systematic reviews and decision models. Systematic reviews are a major component of evidence-based medicine and can be adapted to CER by broadening the types of studies included and examining the full range of benefits and harms of alternative interventions. Decision models are particularly suited to CER, because they make quantitative estimates of expected outcomes based on data from a range of sources. These estimates can be tailored to patient characteristics and can include economic outcomes to assess cost effectiveness. The choice of method for CER is driven by the relative weight placed on concerns about selection bias and generalizability, as well as pragmatic concerns related to data availability and timing. Value of information methods can identify priority areas for investigation and inform research methods.

Outcomes after adjuvant platinum-based chemotherapy in elderly NSCLC patients with T4 disease

BACKGROUND

The postoperative management of elderly patients with T4, N0-1, M0 non-small cell lung cancer (NSCLC) remains controversial. The objective of this study was to evaluate the association of adjuvant chemotherapy with survival and toxicity among these patients.

METHODS

Using surveillance, epidemiology and end results registry data linked to Medicare claims, we identified 389 elderly patients with resected T4, N0-1, M0 NSCLC diagnosed between 1992 and 2007. We compared survival of patients treated with and without platinum-based chemotherapy using a Cox regression adjusting for propensity scores for chemotherapy use and use of radiotherapy. We used logistic regression to assess the risk of adverse events in patients receiving chemotherapy.

RESULTS

No benefit was noted in overall survival with adjuvant chemotherapy after PS adjustment for both N0 (hazard ratio 0.78, 95% confidence interval 0.50-1.23) and N1 (hazard ratio 1.01, 95% confidence interval 0.67-1.53) cancers. Patients receiving adjuvant chemotherapy experienced severe adverse events more frequently than patients who did not receive chemotherapy.

CONCLUSIONS

Use of adjuvant chemotherapy in elderly patients with T4, N0-1, M0 NSCLC was not associated with a survival advantage and was associated with higher rates of severe toxicity.

Patterns of use and short-term complications of breast brachytherapy in the national medicare population from 2008-2009

PURPOSE

Brachytherapy has disseminated into clinical practice as an alternative to whole-breast irradiation (WBI) for early-stage breast cancer; however, current national treatment patterns and associated complications remain unknown.

PATIENTS AND METHODS

We constructed a national sample of Medicare beneficiaries ages 66 to 94 years who underwent breast-conserving surgery from 2008 to 2009 and were treated with brachytherapy or WBI. We used hospital referral regions (HRRs) to assess national treatment variation and an instrumental variable analysis to compare complication rates between treatment groups, adjusting for patient and clinical characteristics. We compared overall, wound and skin, and deep-tissue and bone complications between brachytherapy and WBI at 1 year of follow-up.

RESULTS

Of 29,648 women in our sample, 4,671 (15.8%) received brachytherapy. The percent of patients receiving brachytherapy varied substantially across HRRs, ranging from 0% to over 70% (interquartile range, 7.5% to 23.3%). Of women treated with brachytherapy, 34.3% had a complication compared with 27.3% of women undergoing WBI (P < .001). After adjusting for patient and clinical characteristics, 35.2% of women treated with brachytherapy (95% CI, 28.6 to 41.9) had a complication compared with 18.4% treated with WBI (95% CI, 15.5 to 21.3; P value for difference, <.001). Brachytherapy was associated with a 16.9% higher rate of wound and skin complications compared with WBI (95% CI, 10.0 to 23.9; P < .001), but there was no difference in deep-tissue and bone complications.

CONCLUSION

Brachytherapy is commonly used among Medicare beneficiaries and varies substantially across regions. After 1 year, wound and skin complications were significantly higher among women receiving brachytherapy compared with those receiving WBI.

Long-term results of radiofrequency ablation treatment of stage I non-small cell lung cancer: a prospective intention-to-treat study

INTRODUCTION

About one-fifth of patients with resectable non-small cell lung cancer (NSCLC) are unsuitable for surgical treatment. Radiofrequency ablation offers an alternative minimally invasive option. We report the result of an intention-to-treat study with long-term follow-up.

METHODS

From 2001 to 2009, we performed 80 percutaneous radiofrequency ablations of 59 stage I NSCLC in 57 inoperable patients. Two patients were treated for two separate lesions. The study group consisted of 45 males and 12 females, with mean age of 74 years (range, 40-88 years). All patients had pathological evidence of NSCLC, which was in stage IA in 44 cases and in stage IB in the other 15 cases. The mean size of the lesions was 2.6 cm (range, 1.1-5 cm). Fourteen lesions were retreated up to five times. The procedure was always performed under local anesthesia and conscious sedation. Most of the procedures were performed under computed tomography guidance, with nine under ultrasonography guidance.

RESULTS

In all cases, the procedure was technically successful. No mortality was recorded, and major morbidity consisted of four cases of pneumothorax requiring pleural drainage. At a mean follow-up of 47 months, the complete response rate was 59.3% (stage Ia 65.9%, stage Ib 40%, p = 0.01), with a mean local recurrence interval of 25.9 months. Median overall survival and cancer-specific survival were 33.4 and 41.4 months, respectively. Cancer-specific actuarial survival was 89% at 1 year, 59% at 3 years, and 40% at 5 years.

CONCLUSIONS

Radiofrequency ablation treatment of early-stage NSCLC seems to be a effective minimally invasive therapy even in the long-term period, particularly for stage Ia tumors.

Postoperative radiotherapy for elderly patients with stage III lung cancer

BACKGROUND

The potential role of postoperative radiation therapy (PORT) for patients who have completely resected, stage III nonsmall cell lung cancer (NSCLC) with N2 disease remains controversial. By using population-based data, the authors of this report compared the survival of a concurrent cohort of elderly patients who had N2 disease treated with and without PORT.

METHODS

By using the Surveillance, Epidemiology, and End Results (SEER) registry linked to Medicare records, 1307 patients were identified who had stage III NSCLC with N2 lymph node involvement diagnosed between 1992 and 2005. Propensity scoring methods and instrumental variable analysis were used to compare the survival of patients who did and did not receive PORT after controlling for selection bias.

RESULTS

Overall, 710 patients (54%) received PORT. Propensity score analysis indicated that PORT was not associated with improved survival in patients with N2 disease (hazard ratio [HR], 1.11; 95% confidence interval [CI], 0.97-1.27). Analyses that were limited to patients who did or did not receive chemotherapy, who received intermediate-complexity or high-complexity radiotherapy planning, or adjusted for time trends produced similar results. The instrumental variable estimator for the absolute improvement in 1-year and 3-year survival with PORT was -0.04 (95% CI, -0.15 to 0.08) and -0.08 (95% CI, -0.24 to 0.15), respectively.

CONCLUSIONS

The current data suggested that PORT is not associated with improved survival for elderly patients with N2 disease. These findings have important clinical implications, because SEER data indicate that a large percentage of elderly patients currently receive PORT despite the lack of definitive evidence about its effectiveness. The potential effectiveness of PORT should be evaluated further in randomized controlled trials.

Radiotherapy and chemotherapy for elderly patients with stage I-II unresected lung cancer

Radiotherapy (RT) is the standard therapy for unresected stage I-II nonsmall cell lung cancer (NSCLC). Using population-based data, we compared survival and toxicity among unresected elderly patients treated with combined chemoradiotherapy (CRT) or RT alone. Using the Surveillance, Epidemiology and End Results (SEER) registry (National Cancer Institute, Bethesda, MD, USA) we identified 3,006 cases of unresected stage I-II NSCLC. We used propensity score methods to compare survival and rates of toxicity of patients treated with RT versus CRT. Overall, 844 (28%) patients received CRT. Adjusted analyses showed that CRT was associated with improved survival (hazard ratio 0.85, 95% CI 0.78-0.94). Combination therapy was also associated with better survival among stage I patients treated with intermediate complexity RT (HR 0.80, 95% CI 0.70-0.90); however, no difference in survival was observed among patients treated with complex RT. In stage II patients, CRT was associated with improved survival regardless of the RT technique (HR 0.61-0.72). CRT was associated with increased odds of toxicity. Despite increased toxicity, CRT may improve survival of elderly unresected patients with stage II disease as well as stage I NSCLC treated with intermediate RT complexity. Randomised trials are needed to clarify the balance of benefits and risk of CRT in unresected patients.

Inoperable early stage non-small cell lung cancer: comorbidity, patterns of care and survival

PURPOSE

To evaluate comorbidities, patterns of care and outcomes for patients with inoperable stage I and II non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Patients diagnosed with stage I or II NSCLC in British Columbia between 1996 and 2005 who did not undergo primary surgery and were referred for oncology assessment were identified in a retrospective analysis. Baseline comorbidity and pulmonary function data for patients treated with curative radiotherapy (CurRT; biologically effective dose [BED]>58 Gy(10)) were abstracted by chart review. Kaplan-Meier and Cox regression were used to determine factors associated with overall survival (OS) and cause-specific survival (CSS) based on treatment group [no radiotherapy (NoRT), palliative radiotherapy (PallRT), or CurRT].

RESULTS

Of 1043 patients identified, approximately 1/3 received CurRT, and these patients had better performance status and lower stage disease than the other groups. There was a high prevalence of comorbid conditions in the CurRT group; 90% of CurRT patients had an age-adjusted Charlson comorbidity index (CCI) score ≥5. CurRT patients had a median survival 1-year longer than patients treated with PallRT or NoRT (p < 0.0001). In CurRT patients, CCI was predictive of OS (HR 1.1 per point CCI increase; p = 0.044), but not CSS. Patients receiving PallRT with a BED > 50 Gy(10) had significantly longer OS than those receiving PallRT of ≤50 Gy(10) (p < 0.0001).

CONCLUSIONS

Treatment of medically inoperable early stage NSCLC patients with CurRT is associated with a significantly longer survival, and for these patients CCI is a significant predictor of OS. For patients treated with PallRT, higher doses of palliative thoracic RT is associated with improved OS.

Survival and risk of adverse events in older patients receiving postoperative adjuvant chemotherapy for resected stages II-IIIA lung cancer: observational cohort study

OBJECTIVE

To compare the survival and risk of serious adverse events in older patients with stages II-IIIA non-small cell lung cancer treated with or without postoperative platinum based chemotherapy.

DESIGN

Observational cohort study.

SETTING

Cases of lung cancer in Surveillance Epidemiology and End Results registry linked to Medicare files, 1992-2005, and follow-up data to December 2007.

PARTICIPANTS

3324 patients aged more than 65 years with resected stages II-IIIA lung cancer.

MAIN OUTCOME MEASURES

Primary outcome was overall survival and secondary outcome was the rate of serious adverse events among older patients treated with or without adjuvant chemotherapy.

RESULTS

Overall, 21% (n = 684) of patients received platinum based chemotherapy. Analyses adjusted, stratified, or matched by propensity scores showed that chemotherapy was associated with improved survival (hazard ratio range 0.78-0.81). The beneficial effect of chemotherapy was also observed among patients treated with radiation therapy (0.75-0.77) or without radiation therapy (0.74-0.77); however, chemotherapy was not beneficial for patients aged 80 or more (1.32-1.46). Adjuvant chemotherapy was associated with an increased odds of serious adverse events (odds ratio 2.0, 95% confidence interval 1.5 to 2.6).

CONCLUSIONS

Platinum based adjuvant chemotherapy is associated with reduced mortality and increased risk of serious adverse events in older patients with stages II-IIIA lung cancer. The magnitude of the benefit is similar to that observed in randomised controlled trials carried out among selected patients.

The role of stereotactic ablative radiotherapy for early-stage and oligometastatic non-small cell lung cancer: evidence for changing paradigms

A compelling body of non-randomized evidence has established stereotactic ablative lung radiotherapy (SABR) as a standard of care for medically inoperable patients with peripheral early-stage non-small cell lung cancer (NSCLC). This convenient outpatient therapy, which is typically delivered in 3-8 fractions, is also well tolerated by elderly and frail patients, makes efficient use of resources and is feasible using standard commercial equipment. The introduction of lung SABR into large populations has led to an increased utilization of radiotherapy, a reduction in the proportion of untreated patients and an increase in overall survival. In selected patients, the same ablative technology can now achieve durable local control of NSCLC metastases in a variety of common locations including the adrenal glands, bone, brain, and liver. At the same time as this, advances in prognostic molecular markers and targeted systemic therapies mean that there is now a subgroup of patients with stage IV NSCLC and a median survival of around 2 years. This creates opportunities for new trials that incorporate SABR and patient-specific systemic strategies. This selective mini-review focuses on the emerging role of SABR in patients with early-stage and oligometastatic NSCLC.

Implications of comparative effectiveness research for radiation oncology

PURPOSE

The essence of comparative effectiveness research (CER) is to understand what health interventions work, for which patients, and under what conditions. The objective of this article is to introduce the relative strengths and weaknesses of several forms of evidence to illustrate the potential for CER evidence generation within radiation oncology.

METHODS

We introduce the underlying concepts of effectiveness and efficacy. We describe the design of traditional explanatory randomized trials (RCTs). We introduce the rationale, strengths, and weaknesses of several alternative study designs for comparative effectiveness, including pragmatic clinical trials, adaptive trials, and observational (nonrandomized) studies.

RESULTS

Explanatory RCTs are designed to assess the efficacy of an intervention while achieving a high degree of internal validity. Pragmatic clinical trials (PCTs) are prospective studies performed in typical, real-world clinical practice settings. The emphasis of PCTs is to maintain a degree of internal validity while also maximizing external validity. Adaptive trials can be modified at interim stages using existing or evolving evidence in the course of a trial, which may allow trials to maintain clinical relevance by studying current treatments. Observational data are becoming increasingly important, given substantial funding for clinical registries and greater availability of electronic medical records and claims databases, but need to address well-known limitations such as selection bias.

CONCLUSION

With the rapid proliferation of new and evolving radiotherapy technologies, it is incumbent upon our field to invest in building the evidence base for radiotherapy CER and to actively participate in current initiatives for generating comparative evidence.

Lymph node ratio as a prognostic factor in elderly patients with pathological N1 non-small cell lung cancer

BACKGROUND

Lymph node (LN) metastasis is an important predictor of survival for patients with non-small cell lung cancer (NSCLC). However, the prognostic significance of the extent of LN involvement among patients with N1 disease remains unknown. A study was undertaken to evaluate whether involvement of a higher number of N1 LNs is associated with worse survival independent of known prognostic factors.

METHODS

Using the Surveillance, Epidemiology and End Results-Medicare database, 1682 resected patients with N1 NSCLC diagnosed between 1992 and 2005 were identified. As the number of positive LNs is confounded by the total number of LNs sampled, the cases were classified into three groups according to the ratio of positive to total number of LNs removed (LN ratio (LNR)): ≤0.15, 0.16-0.5 and >0.5. Lung cancer-specific and overall survival was compared between these groups using Kaplan-Meier curves. Stratified and Cox regression analyses were used to evaluate the relationship between the LNR and survival after adjusting for potential confounders.

RESULTS

Lung cancer-specific and overall survival was lower among patients with a high LNR (p<0.0001 for both comparisons). Median lung cancer-specific survival was 47 months, 37 months and 21 months for patients in the ≤0.15, 0.16-0.5 and >0.5 LNR groups, respectively. In stratified and adjusted analyses, a higher LNR was also associated with worse lung cancer-specific and overall survival.

CONCLUSIONS

The extent of LN involvement provides independent prognostic information in patients with N1 NSCLC. This information may be used to identify patients at high risk of recurrence who may benefit from aggressive postoperative therapy.

Effect of radiotherapy planning complexity on survival of elderly patients with unresected localized lung cancer

PURPOSE

To evaluate whether complex radiotherapy (RT) planning was associated with improved outcomes in a cohort of elderly patients with unresected Stage I-II non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

Using the Surveillance, Epidemiology, and End Results registry linked to Medicare claims, we identified 1998 patients aged >65 years with histologically confirmed, unresected stage I-II NSCLC. Patients were classified into an intermediate or complex RT planning group using Medicare physician codes. To address potential selection bias, we used propensity score modeling. Survival of patients who received intermediate and complex simulation was compared using Cox regression models adjusting for propensity scores and in a stratified and matched analysis according to propensity scores.

RESULTS

Overall, 25% of patients received complex RT planning. Complex RT planning was associated with better overall (hazard ratio 0.84; 95% confidence interval, 0.75-0.95) and lung cancer-specific (hazard ratio 0.81; 95% confidence interval, 0.71-0.93) survival after controlling for propensity scores. Similarly, stratified and matched analyses showed better overall and lung cancer-specific survival of patients treated with complex RT planning.

CONCLUSIONS

The use of complex RT planning is associated with improved survival among elderly patients with unresected Stage I-II NSCLC. These findings should be validated in prospective randomized controlled trials.

Propensity scores in intensive care and anaesthesiology literature: a systematic review

INTRODUCTION

Propensity score methods have been increasingly used in the last 10 years. However, the practical use of the propensity score (PS) has been reported as heterogeneous in several papers reviewing the use of propensity scores and giving some advice. No precedent work has focused on the specific application of PS in intensive care and anaesthesiology literature.

OBJECTIVES

After a brief development of the theory of propensity score, to assess the use and the quality of reporting of PS studies in intensive care and anaesthesiology, and to evaluate how past reviews have influenced the quality of the reporting.

STUDY DESIGN AND SETTING

Forty-seven articles published between 2006 and 2009 in the intensive care and anaesthesiology literature were evaluated. We extracted the characteristics of the report, the type of analysis, the details of matching procedures, the number of patients in treated and control groups, and the number of covariates included in the PS models.

RESULTS

Of the 47 articles reviewed, 26 used matching on PS, 12 used stratification on PS and 9 used adjustment on PS. The method used was reported in 81% of the articles, and the choice to conduct a paired analysis or not was reported in only 15%. The comparison with the previously published reviews showed little improvement in reporting in the last few years.

CONCLUSION

The quality of reporting propensity scores in intensive care and anaesthesiology literature should be improved. We provide some recommendations to the investigators in order to improve the reporting of PS analyses.