Abstract 3623: Neoadjuvant chemotherapy is associated with increased expression of DNA repair proteins and epithelial to mesenchymal transition (EMT) in patients with non-small cell lung cancer (NSCLC)

Background: Proteomic profiling has elucidated several dysregulated pathways in NSCLC. We sought to identify patterns of protein expression that are enriched following neoadjuvant chemotherapy in patients with resected lung cancers.

Methods: Tissue samples were selected from the PROSPECT trial at MD Anderson Cancer Center, the goal of which was to correlate molecular profiles with treatment response. Samples from 189 patients were analyzed, which included 26% squamous tumors; 27% with neoadjuvant chemotherapy (n = 49); and predominantly localized disease (distribution: I = 91, II = 35, III = 58, IV = 5). Reverse phase protein array (RPPA) analysis was utilized to quantify 127 total or phosphorylated proteins. Interactions between protein expression and the receipt of neoadjuvant chemotherapy were assessed by analysis of variance (ANOVA). Cox regression was performed to determine the relationship between protein expression and recurrence-free survival (RFS).

Results: Twenty one of the 127 proteins (16%) were expressed at significantly different levels in patients receiving neoadjuvant chemotherapy. Specifically, patients receiving neoadjuvant chemotherapy had higher expression of multiple DNA repair proteins, including MSH2 (p<0.001), 53BP1 (p = 0.01), and p-CHK1 (p = 0.02), as was Rb (p = 0.01), which regulates the expression of several proteins involved in DNA repair. Thymidylate synthase (TS), a target of the chemotherapeutic agent pemetrexed, also showed increased expression (p = 0.02). In addition, there was lower expression of phosphorylated proteins in the PI3K pathway, including p-70S6K (p = 0.008), p-mTOR (p = 0.02), and p-PDK (p = 0.02). Finally, we observed an expression of proteins indicative of an epithelial to mesenchymal transition (EMT), with lower expression of E-cadherin (p = 0.007) and Met (p = 0.03). Notably, there was also lower expression of COL6A, an excreted extracellular protein involved in cellular adhesion (p<0.001), and a trend towards significance in increased expression of stathmin (p = 0.06), a microtubule destabilizer that has previously been implicated in EMT. Finally, we found that higher expression of multiple proteins involved in DNA repair were associated with a reduction in RFS after induction chemotherapy, including p-Rb (p = 0.015), CHK1 (p = 0.027), and p-CHK1 (p = 0.049).

Conclusions: The receipt of neoadjuvant chemotherapy was associated with higher expression of DNA repair proteins, suppression of the PI3K pathway, and an EMT shift. Increased expression of DNA repair proteins was also associated with reduced RFS. These findings suggest that higher expression of DNA repair proteins may contribute to treatment resistance, and support the combination of standard chemotherapy with targeted agents such as Chk inhibitors or immunotherapy (to address EMT-mediated immune escape).

Citation Format: Daniel R. Gomez, Lixia Diao, Jing Wang, Ignacio I. Wistuba, Cesar Moran, Neda Kalhor, Milind B. Suraokar, Stephen G. Swisher, Carmen Behrens, Youhong Fan, John V. Heymach, Lauren A. Byers. Neoadjuvant chemotherapy is associated with increased expression of DNA repair proteins and epithelial to mesenchymal transition (EMT) in patients with non-small cell lung cancer (NSCLC). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3623. doi:10.1158/1538-7445.AM2015-3623

Long-term outcomes after proton therapy, with concurrent chemotherapy, for stage II-III inoperable non-small cell lung cancer

PURPOSE

We report long-term disease control, survival, and toxicity for patients with locally advanced non-small cell lung cancer prospectively treated with concurrent proton therapy and chemotherapy on a nonrandomized case-only observational study.

METHODS

All patients received passive-scatter proton therapy, planned with 4D-CT-based simulation; all received proton therapy concurrent with weekly chemotherapy. Endpoints were local and distant control, disease-free survival (DFS), and overall survival (OS).

RESULTS

The 134 patients (21 stage II, 113 stage III; median age 69 years) had a median gross tumor volume (GTV) of 70 cm(3) (range, 5-753 cm(3)); 77 patients (57%) received 74 Gy(RBE), and 57 (42%) received 60-72 Gy(RBE) (range, 60-74.1 Gy(RBE)). At a median follow-up time of 4.7 years, median OS times were 40.4 months (stage II) and 30.4 months (stage III). Five-year DFS rates were 17.3% (stage II) and 18.0% (stage III). OS, DFS, and local and distant control rates at 5 years did not differ by disease stage. Age and GTV were related to OS and DFS. Toxicity was tolerable, with 1 grade 4 esophagitis and 16 grade 3 events (2 pneumonitis, 6 esophagitis, 8 dermatitis).

CONCLUSION

This report of outcomes after proton therapy for 134 patients indicated that this regimen produced excellent OS with tolerable toxicity.

Time to treatment as a quality metric in lung cancer: Staging studies, time to treatment, and patient survival

PURPOSE

Prompt staging and treatment are crucial for non-small cell lung cancer (NSCLC). We determined if predictors of treatment delay after diagnosis were associated with prognosis.

MATERIALS AND METHODS

Medicare claims from 28,732 patients diagnosed with NSCLC in 2004-2007 were used to establish the diagnosis-to-treatment interval (ideally ⩽35days) and identify staging studies during that interval. Factors associated with delay were identified with multivariate logistic regression, and associations between delay and survival by stage were tested with Cox proportional hazard regression.

RESULTS

Median diagnosis-to-treatment interval was 27days. Receipt of PET was associated with delays (57.4% of patients with PET delayed [n=6646/11,583] versus 22.8% of those without [n=3908/17,149]; adjusted OR=4.48, 95% CI 4.23-4.74, p<0.001). Median diagnosis-to-PET interval was 15days; PET-to-clinic, 5days; and clinic-to-treatment, 12days. Diagnosis-to-treatment intervals <35days were associated with improved survival for patients with localized disease and those with distant disease surviving ⩾1year but not for patients with distant disease surviving <1year.

CONCLUSION

Delays between diagnosing and treating NSCLC are common and associated with use of PET for staging. Reducing time to treatment may improve survival for patients with manageable disease at diagnosis.

The impact of induction chemotherapy on the dosimetric parameters of subsequent radiotherapy: an investigation of 30 consecutive patients with locally-advanced non-small cell lung cancer and modern radiation planning techniques

Purpose

To investigate the influence of induction chemotherapy (ICT) on dosimetric outcomes in patients with inoperable non-small cell lung cancer (NSCLC) treated with definitive chemoradiation (CRT).

Materials and methods

30 patients with inoperable stage II-III NSCLC treated with 2–4 cycles of ICT followed by definitive CRT to ≥ 60 Gy were selected. Tumor response to chemotherapy was scored by RECIST criteria. Treatment plans based on tumor extent prior to chemotherapy were generated based on equivalent planning constraints and techniques as the original post-chemotherapy plans. Dosimetric parameters predictive of toxicity for lung, esophagus, heart, and spinal cord were compared amongst the pre- and post-ICT plans.

Results

The majority of patients (70%) experienced an overall reduction in GTV size between the pre-ICT imaging and the time of simulation. Comparing pre-and post-ICT diagnostic imaging, 5 patients met the RECIST criteria for response, 23 were classified as stable, and 2 experienced disease progression on diagnostic imaging. Despite a significantly reduced GTV size in the post-ICT group, no systematic improvements in normal tissue doses were seen amongst the entire cohort. This result persisted amongst the subgroup of patients with larger pre-ICT GTV tumor volumes (>100 cc³). Among patients with RECIST-defined response, a significant reduction in lung mean dose (1.9 Gy absolute, median 18.2 Gy to 16.4 Gy, p = 0.04) and V_20, the percentage of lung receiving 20 Gy (3.1% absolute, median 29.3% to 26.3%, p = 0.04) was observed. In the non-responding group of patients, an increased esophageal V₅₀ was found post-chemotherapy (median 28.9% vs 30.1%, p = 0.02).

Conclusions

For patients classified as having a response by RECIST to ICT, modest improvements in V₂₀ and mean lung dose were found. However, these benefits were not realized for the cohort as a whole or for patients with larger tumors upfront. Given the variability of tumor response to ICT, the a priori impact of induction chemotherapy to reduce RT dose to normal tissue in these patients is minimal in the setting of modern treatment planning.

Serum inflammatory miRNAs predict radiation esophagitis in patients receiving definitive radiochemotherapy for non-small cell lung cancer

BACKGROUND AND PURPOSE

MicroRNAs (miRNAs) are small, highly conserved non-coding RNAs that regulate many biological processes. We sought to investigate whether three serum miRNAs related to immunity or inflammation were associated with esophagitis induced by chemoradiation therapy (CRT) for non-small cell lung cancer (NSCLC).

MATERIAL AND METHODS

We measured serum miR-155, miR-221 and miR-21, before and during week 1-2 of CRT for 101 NSCLC patients by real-time PCR. Associations between miRNA and severe radiation-induced esophageal toxicity (RIET) were analyzed by logistic regression.

RESULTS

We found that patients with stage IIIB-IV disease, higher mean esophagus dose or esophageal V50 had higher rates of severe RIET. Furthermore, high levels of miR-155 and miR-221 at week 1-2 of CRT were also risk factors for severe RIET (miR-155: OR=1.53, 95% CI: 1.04-2.25, P=0.03; miR-221: OR=2.07, 95% CI: 1.17-3.64, P=0.012). In addition, the fold change of miR-221 was also predictive of severe RIET (OR=1.18, 95% CI: 1.02-1.37, P=0.026). However, pretreatment miRNAs was not predictive of severe RIET.

CONCLUSIONS

High serum miR-155 and miR-221 during the first 2 weeks of CRT were associated with the development of severe RIET, suggesting that these miRNAs may be useful as an early surrogate for this form of toxicity.

Definitive reirradiation for locoregionally recurrent non-small cell lung cancer with proton beam therapy or intensity modulated radiation therapy: predictors of high-grade toxicity and survival outcomes

PURPOSE

Intrathoracic recurrence of non-small cell lung cancer (NSCLC) after initial treatment remains a dominant cause of death. We report our experience using proton beam therapy and intensity modulated radiation therapy for reirradiation in such cases, focusing on patterns of failure, criteria for patient selection, and predictors of toxicity.

METHODS AND MATERIALS

A total of 102 patients underwent reirradiation for intrathoracic recurrent NSCLC at a single institution. All doses were recalculated to an equivalent dose in 2-Gy fractions (EQD2). All patients had received radiation therapy for NSCLC (median initial dose of 70 EQD2 Gy), with median interval to reirradiation of 17 months and median reirradiation dose of 60.48 EQD2 Gy. Median follow-up time was 6.5 months (range, 0-72 months).

RESULTS

Ninety-nine patients (97%) completed reirradiation. Median local failure-free survival, distant metastasis-free survival (DMFS), and overall survival times were 11.43 months (range, 8.6-22.66 months), 11.43 months (range, 6.83-23.84 months), and 14.71 (range, 10.34-20.56 months), respectively. Toxicity was acceptable, with rates of grade ≥3 esophageal toxicity of 7% and grade ≥3 pulmonary toxicity of 10%. Of the patients who developed local failure after reirradiation, 88% had failure in either the original or the reirradiation field. Poor local control was associated with T4 disease, squamous histology, and Eastern Cooperative Oncology Group performance status score >1. Concurrent chemotherapy improved DMFS, but T4 disease was associated with poor DMFS. Higher T status, Eastern Cooperative Oncology Group performance status ≥1, squamous histology, and larger reirradiation target volumes led to worse overall survival; receipt of concurrent chemotherapy and higher EQD2 were associated with improved OS.

CONCLUSIONS

Intensity modulated radiation therapy and proton beam therapy are options for treating recurrent non-small cell lung cancer. However, rates of locoregional recurrence and distant metastasis are high, and patients should be selected carefully to maximize the benefit of additional aggressive local therapy while minimizing the risk of adverse side effects.

Hemithoracic intensity modulated radiation therapy after pleurectomy/decortication for malignant pleural mesothelioma: toxicity, patterns of failure, and a matched survival analysis

PURPOSE

To investigate safety, efficacy, and recurrence after hemithoracic intensity modulated radiation therapy after pleurectomy/decortication (PD-IMRT) and after extrapleural pneumonectomy (EPP-IMRT).

METHODS AND MATERIALS

In 2009-2013, 24 patients with mesothelioma underwent PD-IMRT to the involved hemithorax to a dose of 45 Gy, with an optional integrated boost; 22 also received chemotherapy. Toxicity was scored with the Common Terminology Criteria for Adverse Events v4.0. Pulmonary function was compared at baseline, after surgery, and after IMRT. Kaplan-Meier analysis was used to calculate overall survival (OS), progression-free survival (PFS), time to locoregional failure, and time to distant metastasis. Failures were in-field, marginal, or out of field. Outcomes were compared with those of 24 patients, matched for age, nodal status, performance status, and chemotherapy, who had received EPP-IMRT.

RESULTS

Median follow-up time was 12.2 months. Grade 3 toxicity rates were 8% skin and 8% pulmonary. Pulmonary function declined from baseline to after surgery (by 21% for forced vital capacity, 16% for forced expiratory volume in 1 second, and 19% for lung diffusion of carbon monoxide [P for all = .01]) and declined still further after IMRT (by 31% for forced vital capacity [P=.02], 25% for forced expiratory volume in 1 second [P=.01], and 30% for lung diffusion of carbon monoxide [P=.01]). The OS and PFS rates were 76% and 67%, respectively, at 1 year and 56% and 34% at 2 years. Median OS (28.4 vs 14.2 months, P=.04) and median PFS (16.4 vs 8.2 months, P=.01) favored PD-IMRT versus EPP-IMRT. No differences were found in grade 4-5 toxicity (0 of 24 vs 3 of 24, P=.23), median time to locoregional failure (18.7 months vs not reached, P not calculable), or median time to distant metastasis (18.8 vs 11.8 months, P=.12).

CONCLUSIONS

Hemithoracic intensity modulated radiation therapy after pleurectomy/decortication produced little high-grade toxicity but led to progressive declines in pulmonary function; OS and PFS were better in PD-IMRT compared with EPP-IMRT.

Use of simultaneous radiation boost achieves high control rates in patients with non-small-cell lung cancer who are not candidates for surgery or conventional chemoradiation

BACKGROUND

Intensity-modulated radiation therapy (IMRT) with a simultaneous integrated boost (SIB) has improved the local disease control at a variety of anatomic sites. However, little is known about its use in lung cancer, especially in the context of shorter treatment schedules (hypofractionation). We analyzed the feasibility, toxicity, and patterns of failure of this approach for patients with non-small-cell lung cancer (NSCLC) who were not candidates for surgery or standard concurrent chemoradiation therapy.

PATIENTS AND METHODS

We retrospectively identified 71 patients with NSCLC who received IMRT+SIB in 15 fractions to ≥ 52.5 Gy from January 2007 to February 2013. Toxicity and local control were evaluated for all patients.

RESULTS

Of the 71 patients, 11 (16%) had stage I to II NSCLC, 15 (21%) stage III, and 45 (63%) stage IV. The esophagitis rate was grade 0 to 1 in 55%, grade 2 in 39%, and grade ≥ 3 in 6%. One patient developed a bronchoesophageal fistula 6 months after radiation. The pneumonitis rate was grade 0 to 1 in 93%, grade 2 in 6%, and grade 3 in 1%. At the time of analysis, 17 (24%) patients had local failure at a median of 5.2 months (range, < 1-16.1) after treatment. All but 1 failure occurred within the higher dose region.

CONCLUSION

Hypofractionated IMRT+SIB is a viable option for some patients with NSCLC, with little high-grade toxicity overall. Nearly all local failures occurred within the higher dose region, implying strong radioresistance or some other mechanism for recurrence in a subgroup of patients.

Incidental receipt of cardiac medications and survival outcomes among patients with stage III non-small-cell lung cancer after definitive radiotherapy

BACKGROUND

Preclinical and epidemiologic studies suggest that receipt of some cardiac medications such as angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs), β-blockers, or aspirin may have antiproliferative effects in several types of cancer. The aim of this study was to estimate survival outcomes in patients receiving incidental cardiac medications during treatment for lung cancer, and to compare outcomes with those patients not receiving these medications.

PATIENTS AND METHODS

We retrospectively reviewed 673 patients who had received definitive radiotherapy for stage III non-small-cell lung cancer (NSCLC). Cox proportional hazard models were used to assess associations between receipt of ACEIs, ARBs, β-blockers, or aspirin and locoregional progression-free survival (LRPFS), distant metastasis-free survival (DMFS), disease-free survival (DFS), and overall survival (OS).

RESULTS

Multivariate analyses showed that ACEI receipt was associated with poorer LRPFS but had no effect on DMFS, DFS, or OS. Aspirin receipt was associated only with improved DMFS, and β-blocker receipt was associated with improved DMFS, DFS, and OS.

CONCLUSION

Incidental receipt of ACEIs was associated with a higher prevalence of local failure, whereas receipt of either β-blockers or aspirin had protective effects on survival outcomes in this large group of patients with lung cancer. This finding warrants further clinical and preclinical exploration, as it may have important implications for treating patients with lung cancer who are also receiving cardiac medications.

Clinical implementation of intensity modulated proton therapy for thoracic malignancies

PURPOSE

Intensity modulated proton therapy (IMPT) can improve dose conformality and better spare normal tissue over passive scattering techniques, but range uncertainties complicate its use, particularly for moving targets. We report our early experience with IMPT for thoracic malignancies in terms of motion analysis and management, plan optimization and robustness, and quality assurance.

METHODS AND MATERIALS

Thirty-four consecutive patients with lung/mediastinal cancers received IMPT to a median 66 Gy(relative biological equivalence [RBE]). All patients were able to undergo definitive radiation therapy. IMPT was used when the treating physician judged that IMPT conferred a dosimetric advantage; all patients had minimal tumor motion (<5 mm) and underwent individualized tumor-motion dose-uncertainty analysis and 4-dimensional (4D) computed tomographic (CT)-based treatment simulation and motion analysis. Plan robustness was optimized by using a worst-case scenario method. All patients had 4D CT repeated simulation during treatment.

RESULTS

IMPT produced lower mean lung dose (MLD), lung V5 and V20, heart V40, and esophageal V60 than did IMRT (P<.05) and lower MLD, lung V20, and esophageal V60 than did passive scattering proton therapy (PSPT) (P<.05). D5 to the gross tumor volume and clinical target volume was higher with IMPT than with intensity modulated radiation therapy or PSPT (P<.05). All cases were analyzed for beam-angle-specific motion, water-equivalent thickness, and robustness. Beam angles were chosen to minimize the effect of respiratory motion and avoid previously treated regions, and the maximum deviation from the nominal dose-volume histogram values was kept at <5% for the target dose and met the normal tissue constraints under a worst-case scenario. Patient-specific quality assurance measurements showed that a median 99% (range, 95% to 100%) of the pixels met the 3% dose/3 mm distance criteria for the γ index. Adaptive replanning was used for 9 patients (26.5%).

CONCLUSIONS

IMPT using 4D CT-based planning, motion management, and optimization was implemented successfully and met our quality assurance parameters for treating challenging thoracic cancers.

Propensity score-matched analysis of comprehensive local therapy for oligometastatic non-small cell lung cancer that did not progress after front-line chemotherapy

PURPOSE

To retrospectively analyze factors influencing survival in patients with non-small cell lung cancer presenting with ≤3 synchronous metastatic lesions.

METHODS AND MATERIALS

We identified 90 patients presenting between 1998 and 2012 with non-small cell lung cancer and ≤3 metastatic lesions who had received at least 2 cycles of chemotherapy followed by surgery or radiation therapy before disease progression. The median number of chemotherapy cycles before comprehensive local therapy (CLT) (including concurrent chemoradiation as first-line therapy) was 6. Factors potentially affecting overall (OS) or progression-free survival (PFS) were evaluated with Cox proportional hazards regression. Propensity score matching was used to assess the efficacy of CLT.

RESULTS

Median follow-up time was 46.6 months. Benefits in OS (27.1 vs 13.1 months) and PFS (11.3 months vs 8.0 months) were found with CLT, and the differences were statistically significant when propensity score matching was used (P ≤ .01). On adjusted analysis, CLT had a statistically significant benefit in terms of OS (hazard ratio, 0.37; 95% confidence interval, 0.20-0.70; P ≤ .01) but not PFS (P=.10). In an adjusted subgroup analysis of patients receiving CLT, favorable performance status (hazard ratio, 0.43; 95% confidence interval, 0.22-0.84; P=.01) was found to predict improved OS.

CONCLUSIONS

Comprehensive local therapy was associated with improved OS in an adjusted analysis and seemed to favorably influence OS and PFS when factors such as N status, number of metastatic lesions, and disease sites were controlled for with propensity score-matched analysis. Patients with favorable performance status had improved outcomes with CLT. Ultimately, prospective, randomized trials are needed to provide definitive evidence as to the optimal treatment approach for this patient population.

Stereotactic ablative radiotherapy (SABR) using 70 Gy in 10 fractions for non-small cell lung cancer: exploration of clinical indications

BACKGROUND AND PURPOSE

We report our outcomes for patients with NSCLC treated with SABR to 70 Gy in 10 fractions and propose indications for this regimen as well as new dose-volume constraints.

MATERIALS AND METHODS

Volumetric image-guided SABR was used to treat 82 patients with clinical challenging NSCLC, not suitable for 50 Gy in 4 fractions, to a final dose of 70 Gy in 10 fractions. Endpoints included overall survival (OS), toxicity, and disease control.

RESULTS

At a median follow-up time of 21.1 months, 2-year OS and local control rates were 66.9% and 96.2%, respectively. The most common side effects were radiation pneumonitis (14.6% grade 2, 2.4% grade 3), followed by chest wall pain (4.9% grade 2, 1.2% grade 3). Multivariate analysis revealed chest wall V50>60 cm(3) to be associated with chest wall pain. No patient developed brachial plexopathy. One patient with bronchial tree tumor invasion died of hemoptysis.

CONCLUSIONS

SABR with 70 Gy in 10 fractions appears to achieve excellent local control and acceptable toxicity for clinically challenging cases with improved tolerance of the chest wall and brachial plexus as compared with 50 Gy in 4 fractions. This regimen may not be suitable in patients with tumor invading critical central structures. More studies are needed to validate our conclusions.

Accelerated dose escalation with proton beam therapy for non-small cell lung cancer

Local tumor control remains challenging in many cases of non-small cell lung cancer (NSCLC), particularly those that involve large or centrally located tumors. Concurrent chemotherapy and radiation can maximize tumor control and survival for patients with locally advanced disease, but a substantial proportion of such patients cannot tolerate this therapy, and sequential chemoradiation regimens or radiation given alone at conventionally fractionated doses produces suboptimal results. An alternative approach is the use of hypofractionated proton beam therapy (PBT). The energy distribution of protons can be exploited to reduce involuntary irradiation of normal tissues, particularly the low-dose irradiation problematic in intensity-modulated (photon) radiation therapy (IMRT). Here we summarize current evidence on the use of hypofractionated PBT for both early-stage and locally advanced NSCLC, and the possibility of using hypofractionated regimens for patients who are not candidates for concurrent chemotherapy.

An individual patient data metaanalysis of outcomes and prognostic factors after treatment of oligometastatic non-small-cell lung cancer

INTRODUCTION/BACKGROUND

An individual patient data metaanalysis was performed to determine clinical outcomes, and to propose a risk stratification system, related to the comprehensive treatment of patients with oligometastatic NSCLC.

MATERIALS AND METHODS

After a systematic review of the literature, data were obtained on 757 NSCLC patients with 1 to 5 synchronous or metachronous metastases treated with surgical metastectomy, stereotactic radiotherapy/radiosurgery, or radical external-beam radiotherapy, and curative treatment of the primary lung cancer, from hospitals worldwide. Factors predictive of overall survival (OS) and progression-free survival were evaluated using Cox regression. Risk groups were defined using recursive partitioning analysis (RPA). Analyses were conducted on training and validating sets (two-thirds and one-third of patients, respectively).

RESULTS

Median OS was 26 months, 1-year OS 70.2%, and 5-year OS 29.4%. Surgery was the most commonly used treatment for the primary tumor (635 patients [83.9%]) and metastases (339 patients [62.3%]). Factors predictive of OS were: synchronous versus metachronous metastases (P < .001), N-stage (P = .002), and adenocarcinoma histology (P = .036); the model remained predictive in the validation set (c-statistic = 0.682). In RPA, 3 risk groups were identified: low-risk, metachronous metastases (5-year OS, 47.8%); intermediate risk, synchronous metastases and N0 disease (5-year OS, 36.2%); and high risk, synchronous metastases and N1/N2 disease (5-year OS, 13.8%).

CONCLUSION

Significant OS differences were observed in oligometastatic patients stratified according to type of metastatic presentation, and N status. Long-term survival is common in selected patients with metachronous oligometastases. We propose this risk classification scheme be used in guiding selection of patients for clinical trials of ablative treatment.

Assessing the robustness of passive scattering proton therapy with regard to local recurrence in stage III non-small cell lung cancer: a secondary analysis of a phase II trial

Background

We assessed the robustness of passive scattering proton therapy (PSPT) plans for patients in a phase II trial of PSPT for stage III non-small cell lung cancer (NSCLC) by using the worst-case scenario method, and compared the worst-case dose distributions with the appearance of locally recurrent lesions.

Methods

Worst-case dose distributions were generated for each of 9 patients who experienced recurrence after concurrent chemotherapy and PSPT to 74 Gy(RBE) for stage III NSCLC by simulating and incorporating uncertainties associated with set-up, respiration-induced organ motion, and proton range in the planning process. The worst-case CT scans were then fused with the positron emission tomography (PET) scans to locate the recurrence.

Results

Although the volumes enclosed by the prescription isodose lines in the worst-case dose distributions were consistently smaller than enclosed volumes in the nominal plans, the target dose coverage was not significantly affected: only one patient had a recurrence outside the prescription isodose lines in the worst-case plan.

Conclusions

PSPT is a relatively robust technique. Local recurrence was not associated with target underdosage resulting from estimated uncertainties in 8 of 9 cases.

Genetic variants of the LIN28B gene predict severe radiation pneumonitis in patients with non-small cell lung cancer treated with definitive radiation therapy

BACKGROUND

LIN28 is an RNA-binding protein that not only plays key roles in multiple cellular developmental processes and tumourigenesis, but also is involved in tissue inflammatory response. However, no published study has investigated associations between genetic variants in LIN28 and radiation-induced pneumonitis (RP) in patients with non-small cell lung cancer (NSCLC) treated with definitive radiation therapy.

METHODS

We genotyped eight potentially functional single nucleotide polymorphisms (SNPs) of LIN28A (rs11247946 T>C, rs3811464 C>T, rs11581746 T>C, and rs12728900 G>A) and LIN28B (rs314280 G>A, rs12194974 G>A, rs17065417 A>C and rs314276 C>A) in 362 patients with NSCLC, who received definitive radio(chemo)therapy. The associations between RP risk and genotypes were assessed by hazards ratio (HR) in Cox proportional hazards regression analysis with time to event considered with and without adjustment for potential confounders.

RESULTS

Multivariate analyses found that patients carrying LIN28B rs314280 AG and AA/AG or rs314276 AC and AA/AC genotypes had a higher risk of grade ⩾3 RP (for rs314280 AG and AA/AG versus GG, adjusted HR=2.97 and 2.23, 95% confidence interval (CI)=1.32-6.72 and 1.01-4.94, P=0.009 and 0.048, respectively; for rs314276 AC and AA/AC versus CC, adjusted HR=2.30 and 2.00, 95% CI=1.24-4.28 and 1.11-3.62, and P=0.008 and 0.022, respectively). Further stratified analyses showed a more consistent and profound risk in the subgroups of age <65years, males, stage III/IV, ever smokers, having radio-chemotherapy and mean lung dose (MLD) ⩾19.0Gy.

CONCLUSION

Genetic variants of LIN28B, but not LIN28A, may be biomarkers for susceptibility to severe RP in NSCLC patients. Large, prospective studies are needed to confirm our findings.

Stereotactic ablative radiation therapy for centrally located early stage or isolated parenchymal recurrences of non-small cell lung cancer: how to fly in a "no fly zone"

PURPOSE

We extended our previous experience with stereotactic ablative radiation therapy (SABR; 50 Gy in 4 fractions) for centrally located non-small cell lung cancer (NSCLC); explored the use of 70 Gy in 10 fractions for cases in which dose-volume constraints could not be met with the previous regimen; and suggested modified dose-volume constraints.

METHODS AND MATERIALS

Four-dimensional computed tomography (4DCT)-based volumetric image-guided SABR was used for 100 patients with biopsy-proven, central T1-T2N0M0 (n=81) or isolated parenchymal recurrence of NSCLC (n=19). All disease was staged with positron emission tomography/CT; all tumors were within 2 cm of the bronchial tree, trachea, major vessels, esophagus, heart, pericardium, brachial plexus, or vertebral body. Endpoints were toxicity, overall survival (OS), local and regional control, and distant metastasis.

RESULTS

At a median follow-up time of 30.6 months, median OS time was 55.6 months, and the 3-year OS rate was 70.5%. Three-year cumulative actuarial local, regional, and distant control rates were 96.5%, 87.9%, and 77.2%, respectively. The most common toxicities were chest-wall pain (18% grade 1, 13% grade 2) and radiation pneumonitis (11% grade 2 and 1% grade 3). No patient experienced grade 4 or 5 toxicity. Among the 82 patients receiving 50 Gy in 4 fractions, multivariate analyses showed mean total lung dose >6 Gy, V20 >12%, or ipsilateral lung V30 >15% to independently predict radiation pneumonitis; and 3 of 9 patients with brachial plexus Dmax >35 Gy experienced brachial neuropathy versus none of 73 patients with brachial Dmax <35 Gy (P=.001). Other toxicities were analyzed and new dose-volume constraints are proposed.

CONCLUSIONS

SABR for centrally located lesions produces clinical outcomes similar to those for peripheral lesions when normal tissue constraints are respected.

Association between white blood cell count following radiation therapy with radiation pneumonitis in non-small cell lung cancer

PURPOSE

Radiation pneumonitis (RP) is an inflammatory response to radiation therapy (RT). We assessed the association between RP and white blood cell (WBC) count, an established metric of systemic inflammation, after RT for non-small cell lung cancer.

METHODS AND MATERIALS

We retrospectively analyzed 366 patients with non-small cell lung cancer who received ≥60 Gy as definitive therapy. The primary endpoint was whether WBC count after RT (defined as 2 weeks through 3 months after RT completion) was associated with grade ≥3 or grade ≥2 RP. Median lung volume receiving ≥20 Gy (V20) was 31%, and post-RT WBC counts ranged from 1.7 to 21.2 × 10(3) WBCs/μL. Odds ratios (ORs) associating clinical variables and post-RT WBC counts with RP were calculated via logistic regression. A recursive-partitioning algorithm was used to define optimal post-RT WBC count cut points.

RESULTS

Post-RT WBC counts were significantly higher in patients with grade ≥3 RP than without (P<.05). Optimal cut points for post-RT WBC count were found to be 7.4 and 8.0 × 10(3)/μL for grade ≥3 and ≥2 RP, respectively. Univariate analysis revealed significant associations between post-RT WBC count and grade ≥3 (n=46, OR=2.6, 95% confidence interval [CI] 1.4‒4.9, P=.003) and grade ≥2 RP (n=164, OR=2.0, 95% CI 1.2‒3.4, P=.01). This association held in a stepwise multivariate regression. Of note, V20 was found to be significantly associated with grade ≥2 RP (OR=2.2, 95% CI 1.2‒3.4, P=.01) and trended toward significance for grade ≥3 RP (OR=1.9, 95% CI 1.0-3.5, P=.06).

CONCLUSIONS

Post-RT WBC counts were significantly and independently associated with RP and have potential utility as a diagnostic or predictive marker for this toxicity.

Radiotherapy for thymic carcinoma: adjuvant, inductive, and definitive

Although historically thymoma and thymic carcinoma have been treated surgically, radiation therapy also has an important role, either as postoperative therapy to reduce the risk of mediastinal recurrence or as part of definitive treatment for patients who cannot undergo surgery. Induction chemotherapy and molecular targeted agents may also be appropriate for thymic carcinoma, the behavior of which resembles non-small-cell lung carcinoma more than that of thymoma or invasive thymoma and is increasingly being treated like lung cancer. We present here a review of current therapies for thymic malignancies and briefly discuss the potential benefits from novel technologies for such treatment.

Intensity modulated radiotherapy for stage III non-small cell lung cancer in the United States: predictors of use and association with toxicities

BACKGROUND

Intensity modulated radiotherapy for stage III lung cancer has become commonplace in the United States in the absence of randomized controlled trials. We used a large, population-based database to determine which factors led to increased utilization of IMRT and to evaluate associations of IMRT with toxicities.

METHODS

The Surveillance, Epidemiology, and End Results (SEER)-Medicare records identified 3986 individuals aged 66 years or older diagnosed with stage III lung cancer between 2001 and 2007 and treated with IMRT or 3D conformal radiotherapy. Predictors of IMRT use were determined using logistic regression. Associations of IMRT use with diagnosis codes for radiation-related toxicities were evaluated with multivariate proportional hazards regression and propensity-score matching.

RESULTS

Among the 3986 patients studied, the median age was 75 years, 54.1% were male, and 62% had IIIA disease. Two hundred and fifty seven (6.5%) patients received IMRT, with use increasing from 0.5% in 2001 to 14.7% in 2007 (P < 0.001). Key predictors of IMRT delivery included increasing year of diagnosis and treatment in a freestanding center (odds ratio, 2.10; 95% confidence interval [CI], 1.59-2.77, P < 0.001); tumor size, stage, and number of radiotherapy fractions delivered were not associated with IMRT use. IMRT use was not associated with a higher burden of lung or esophagus toxicities when compared to 3DCRT.

CONCLUSION

These findings suggest that practice environment strongly influenced adoption of IMRT for lung cancer. Patient and tumor factors were not significant predictors of IMRT use. Esophagus and lung toxicity rates were similar between IMRT and 3DCRT.

Do angiotensin-converting enzyme inhibitors reduce the risk of symptomatic radiation pneumonitis in patients with non-small cell lung cancer after definitive radiation therapy? Analysis of a single-institution database

PURPOSE

Preclinical studies have suggested that angiotensin-converting enzyme inhibitors (ACEIs) can mitigate radiation-induced lung injury. We sought here to investigate possible associations between ACEI use and the risk of symptomatic radiation pneumonitis (RP) among patients undergoing radiation therapy (RT) for non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

We retrospectively identified patients who received definitive radiation therapy for stages I to III NSCLC between 2004 and 2010 at a single tertiary cancer center. Patients must have received a radiation dose of at least 60 Gy for a single primary lung tumor and have had imaging and dosimetric data available for analysis. RP was quantified according to Common Terminology Criteria for Adverse Events, version 3.0. A Cox proportional hazard model was used to assess potential associations between ACEI use and risk of symptomatic RP.

RESULTS

Of 413 patients analyzed, 65 were using ACEIs during RT. In univariate analysis, the rate of RP grade ≥2 seemed lower in ACEI users than in nonusers (34% vs 46%), but this apparent difference was not statistically significant (P=.06). In multivariate analysis of all patients, ACEI use was not associated with the risk of symptomatic RP (hazard ratio [HR] = 0.66; P=.07) after adjustment for sex, smoking status, mean lung dose (MLD), and concurrent carboplatin and paclitaxel chemotherapy. Subgroup analysis showed that ACEI use did have a protective effect from RP grade ≥2 among patients who received a low (≤20-Gy) MLD (P<.01) or were male (P=.04).

CONCLUSIONS

A trend toward reduction in symptomatic RP among patients taking ACEIs during RT for NSCLC was not statistically significant on univariate or multivariate analyses, although certain subgroups may benefit from use (ie, male patients and those receiving low MLD). The evidence at this point is insufficient to establish whether the use of ACEIs does or does not reduce the risk of RP.

Feasibility of proton beam therapy for reirradiation of locoregionally recurrent non-small cell lung cancer

BACKGROUND AND PURPOSE

Options are limited for patients with intrathoracic recurrence of non-small cell lung cancer (NSCLC) who previously received radiation. We report our 5-year experience with the toxicity and efficacy of proton beam therapy (PBT) for reirradiation.

MATERIALS AND METHODS

Thirty-three patients underwent PBT reirradiation for intrathoracic recurrent NSCLC at a single institution. All patients had had RT for NSCLC (median initial dose 63 Gy in 33 fractions), with median interval to reirradiation of 36 months. Median reirradiation dose was 66 Gy (RBE) in 32 fractions. Toxicity was scored with CTCAE v4.0, and survival outcomes were estimated using Kaplan-Meier.

RESULTS

Thirty-one patients (94%) completed reirradiation. At a median 11 months' follow-up, 1-year rates of overall survival, progression-free survival, locoregional control, and distant metastasis-free survival were 47%, 28%, 54%, and 39%. Rates of severe (grade ≥3) toxicity were 9% esophageal, 21% pulmonary; 1 patient had grade 4 esophagitis, and 2 had grade 4 pulmonary toxicity. Nine patients experienced a second in-field failure.

CONCLUSIONS

PBT is an option for treating recurrent NSCLC. However, the rates of locoregional recurrence and distant metastasis are high and the potential for toxicity significant. The risks and benefits of PBT must be carefully weighed in each case.

Patterns of failure, toxicity, and survival after extrapleural pneumonectomy and hemithoracic intensity-modulated radiation therapy for malignant pleural mesothelioma

INTRODUCTION

We investigated safety, efficacy, and recurrence after postoperative hemithoracic intensity-modulated radiation therapy (IMRT) in patients with malignant pleural mesothelioma treated with extrapleural pneumonectomy (EPP), during the past decade at a single institution.

METHODS

In 2001-2011, 136 consecutive patients with malignant pleural mesothelioma underwent EPP with planned adjuvant IMRT. Eighty-six patients (64%) underwent hemithoracic IMRT; the rest were not eligible because of postoperative complications, disease progression, or poor performance status. We assessed toxicity, survival, and patterns of failure in these 86 patients. Toxicity was scored with the Common Terminology Criteria for Adverse Events version 4.0; survival outcomes were estimated with the Kaplan-Meier method; and locoregional patterns of failure were classified as in-field, marginal, or out-of-field. Risk factors related to survival were identified by univariate and multivariate Cox regression analysis.

RESULTS

Median overall survival time for all 86 patients receiving IMRT was 14.7 months. Toxicity rates of grade of 3 or more were: skin 17%, lung 12%, heart 2.3%, and gastrointestinal toxicity 16%. Five patients experienced grade 5 pulmonary toxicity. Rates of locoregional recurrence-free survival, distant metastasis-free survival, and overall survival (OS) were 88%, 55%, and 55% at 1 year and 71%, 40%, and 32% at 2 years. On multivariate analysis, pretreatment forced expiratory volume in 1 second, nonepithelioid histology, and nodal status were associated with distant metastasis-free survival and OS.

CONCLUSION

IMRT after EPP is associated with low rates of locoregional recurrence, though some patients experience life-threatening lung toxicity. Tumor histology and nodal status can be helpful in identifying patients for this aggressive treatment.