Leveraging radiomics and machine learning to differentiate radiation necrosis from recurrence in patients with brain metastases

OBJECTIVE

Radiation necrosis (RN) can be difficult to radiographically discern from tumor progression after stereotactic radiosurgery (SRS). The objective of this study was to investigate the utility of radiomics and machine learning (ML) to differentiate RN from recurrence in patients with brain metastases treated with SRS.

METHODS

Patients with brain metastases treated with SRS who developed either RN or tumor reccurence were retrospectively identified. Image preprocessing and radiomic feature extraction were performed using ANTsPy and PyRadiomics, yielding 105 features from MRI T1-weighted post-contrast (T1c), T2, and fluid-attenuated inversion recovery (FLAIR) images. Univariate analysis assessed significance of individual features. Multivariable analysis employed various classifiers on features identified as most discriminative through feature selection. ML models were evaluated through cross-validation, selecting the best model based on area under the receiver operating characteristic (ROC) curve (AUC). Specificity, sensitivity, and F1 score were computed.

RESULTS

Sixty-six lesions from 55 patients were identified. On univariate analysis, 27 features from the T1c sequence were statistically significant, while no features were significant from the T2 or FLAIR sequences. For clinical variables, only immunotherapy use after SRS was significant. Multivariable analysis of features from the T1c sequence yielded an AUC of 76.2% (standard deviation [SD] ± 12.7%), with specificity and sensitivity of 75.5% (± 13.4%) and 62.3% (± 19.6%) in differentiating radionecrosis from recurrence.

CONCLUSIONS

Radiomics with ML may assist the diagnostic ability of distinguishing RN from tumor recurrence after SRS. Further work is needed to validate this in a larger multi-institutional cohort and prospectively evaluate it's utility in patient care.

Combining Dual Checkpoint Immunotherapy with Ablative Radiation to All Sites of Oligometastatic Non-Small Cell Lung Cancer: Toxicity and Efficacy Results of a Phase 1b Trial

PURPOSE

Ablative local treatment of all radiographically detected metastatic sites in patients with oligometastatic non-small cell lung cancer (NSCLC) increases progression-free survival (PFS) and overall survival (OS). Prior studies demonstrated the safety of combining stereotactic body radiation therapy (SBRT) with single-agent immunotherapy. We investigated the safety of combining SBRT to all metastatic tumor sites with dual checkpoint, anticytotoxic T-lymphocyte-associated protein 4 (anti-CTLA-4), and anti-programmed cell death ligand 1 (anti-PD-L1) immunotherapy for patients with oligometastatic NSCLC.

METHODS AND MATERIALS

We conducted a phase 1b clinical trial in patients with oligometastatic NSCLC with up to 6 sites of extracranial metastatic disease. All sites of disease were treated with SBRT to a dose of 30 to 50 Gy in 5 fractions. Dual checkpoint immunotherapy was started 7 days after completion of radiation using anti-CTLA-4 (tremelimumab) and anti-PD-L1 (durvalumab) immunotherapy for a total of 4 cycles followed by durvalumab alone until progression or toxicity.

RESULTS

Of the 17 patients enrolled in this study, 15 patients received at least 1 dose of combination immunotherapy per protocol. The study was closed early (17 of planned 21 patients) due to slow accrual during the COVID-19 pandemic. Grade 3+ treatment-related adverse events were observed in 6 patients (40%), of which only one was possibly related to the addition of SBRT to immunotherapy. Median PFS was 42 months and median OS has not yet been reached.

CONCLUSIONS

Delivering ablative SBRT to all sites of metastatic disease in combination with dual checkpoint immunotherapy did not result in excessive rates of toxicity compared with historical studies of dual checkpoint immunotherapy alone. Although the study was not powered for treatment efficacy results, durable PFS and OS results suggest potential therapeutic benefit compared with immunotherapy or radiation alone in this patient population.

MET Inhibitor Capmatinib Radiosensitizes MET Exon 14-Mutated and MET-Amplified Non-Small Cell Lung Cancer

PURPOSE

The objective of this study was to investigate the effects of inhibiting the MET receptor with capmatinib, a potent and clinically relevant ATP-competitive tyrosine kinase inhibitor, in combination with radiation in MET exon 14-mutated and MET-amplified non-small cell lung (NSCLC) cancer models.

METHODS AND MATERIALS

In vitro effects of capmatinib and radiation on cell proliferation, colony formation, MET signaling, apoptosis, and DNA damage repair were evaluated. In vivo tumor responses were assessed in cell line xenograft and patient-derived xenograft models. Immunohistochemistry was used to confirm the in vitro results.

RESULTS

In vitro clonogenic survival assays demonstrated radiosensitization with capmatinib in both MET exon 14-mutated and MET-amplified NSCLC cell lines. No radiation-enhancing effect was observed in MET wild-type NSCLC and a human bronchial epithelial cell line. Minimal apoptosis was detected with the combination of capmatinib and radiation. Capmatinib plus radiation compared with radiation alone resulted in inhibition of DNA double-strand break repair, as measured by prolonged expression of γH2AX. In vivo, the combination of capmatinib and radiation significantly delayed tumor growth compared with vehicle control, capmatinib alone, or radiation alone. Immunohistochemistry indicated inhibition of phospho-MET and phospho-S6 and a decrease in Ki67 with inhibition of MET.

CONCLUSIONS

Inhibition of MET with capmatinib enhances the effect of radiation in both MET exon 14-mutated and MET-amplified NSCLC models.

Development of an Engineered Single-Domain Antibody for Targeting MET in Non-Small Cell Lung Cancer

The Mesenchymal Epithelial Transition (MET) receptor tyrosine kinase is upregulated or mutated in 5% of non-small-cell lung cancer (NSCLC) patients and overexpressed in multiple other cancers. We sought to develop a novel single-domain camelid antibody with high affinity for MET that could be used to deliver conjugated payloads to MET expressing cancers. From a naïve camelid variable-heavy-heavy (VHH) domain phage display library, we identified a VHH clone termed 1E7 that displayed high affinity for human MET and was cross-reactive with MET across multiple species. When expressed as a bivalent human Fc fusion protein, 1E7-Fc was found to selectively bind to EBC-1 (MET amplified) and UW-Lung 21 (MET exon 14 mutated) cell lines by flow cytometry and immunofluorescence imaging. Next, we investigated the ability of [89Zr]Zr-1E7-Fc to detect MET expression in vivo by PET/CT imaging. [89Zr]Zr-1E7-Fc demonstrated rapid localization and high tumor uptake in both xenografts with a %ID/g of 6.4 and 5.8 for EBC-1 and UW-Lung 21 at 24 h, respectively. At the 24 h time point, clearance from secondary and nontarget tissues was also observed. Altogether, our data suggest that 1E7-Fc represents a platform technology that can be employed to potentially both image and treat MET-altered NSCLC.

A Phase 2 Randomized Clinical Trial Evaluating 4DCT Ventilation-based Functional Lung Avoidance Radiotherapy for Non-Small Cell Lung Cancer

PURPOSE

To determine whether 4-dimensional computed tomography (4DCT) ventilation-based functional lung avoidance radiotherapy preserves pulmonary function compared with standard radiotherapy for non-small cell lung cancer (NSCLC).

MATERIAL AND METHODS

This single center, randomized, phase 2 trial enrolled patients with NSCLC receiving curative intent radiotherapy with either stereotactic body radiotherapy or conventionally fractionated radiotherapy between 2016 and 2022. Patients were randomized 1:1 to standard of care radiotherapy or functional lung avoidance radiotherapy. The primary endpoint was the change in Jacobian-based ventilation as measured on 4DCT from baseline to three months post-radiation. Secondary endpoints included changes in volume of high- and low-ventilating lung, pulmonary toxicity, and changes in pulmonary function tests (PFTs).

RESULTS

A total of 122 patients were randomized and 116 were available for analysis. Median follow up was 29.9 months. Functional avoidance plans significantly (P<.05) reduced dose to high-functioning lung without compromising target coverage or organs at risk constraints. When analyzing all patients, there was no difference in the amount of lung showing a reduction in ventilation from baseline to 3 months between the two arms (1.91% vs 1.87%; P=.90). Overall grade ≥2 and grade ≥3 pulmonary toxicities for all patients were 24.1% and 8.6%, respectively. There was no significant difference in pulmonary toxicity or changes in PFTs between the two study arms. In the conventionally fractionated cohort, there was a lower rate of grade ≥2 pneumonitis (8.2% vs 32.3%; P=.049) and less of a decline in change in FEV1 (-3 vs -5; P=.042) and FVC (1.5 vs -6; P=.005) at 3 months, favoring the functional avoidance arm.

CONCLUSIONS

There was no difference in post-treatment ventilation as measured by 4DCT between the arms. In the cohort of patients treated with conventionally fractionated radiotherapy with functional lung avoidance, there was reduced pulmonary toxicity, and less decline in PFTs suggesting a clinical benefit in patients with locally advanced NSCLC.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCTXXXX Anonymized for Review XXXX.

GABA(A) receptor activation drives GABARAP-Nix mediated autophagy to radiation-sensitize primary and brain-metastatic lung adenocarcinoma tumors

In non-small cell lung cancer (NSCLC) treatment, targeted therapies benefit only a subset of NSCLC, while radiotherapy responses are not durable and toxicity limits therapy. We find that a GABA(A) receptor activator, AM-101, impairs viability and clonogenicity of NSCLC primary and brain metastatic cells. Employing an ex vivo 'chip', AM-101 is as efficacious as the chemotherapeutic docetaxel, which is used with radiotherapy for advanced-stage NSCLC. In vivo , AM-101 potentiates radiation, including conferring a survival benefit to mice bearing NSCLC intracranial tumors. GABA(A) receptor activation stimulates a selective-autophagic response via multimerization of GABA(A) Receptor-Associated Protein (GABARAP), stabilization of mitochondrial receptor Nix, and utilization of ubiquitin-binding protein p62. A targeted-peptide disrupting Nix binding to GABARAP inhibits AM-101 cytotoxicity. This supports a model of GABA(A) receptor activation driving a GABARAP-Nix multimerization axis triggering autophagy. In patients receiving radiotherapy, GABA(A) receptor activation may improve tumor control while allowing radiation dose de-intensification to reduce toxicity.

Highlights

Activating GABA(A) receptors intrinsic to lung primary and metastatic brain cancer cells triggers a cytotoxic response. GABA(A) receptor activation works as well as chemotherapeutic docetaxel in impairing lung cancer viability ex vivo . GABA(A) receptor activation increases survival of mice bearing lung metastatic brain tumors.A selective-autophagic response is stimulated by GABA(A) receptor activation that includes multimerization of GABARAP and Nix.Employing a new nanomolar affinity peptide that abrogates autophagosome formation inhibits cytotoxicity elicited by GABA(A) receptor activation.

Toxicity and Patient-Reported Quality-of-Life Outcomes After Prostate Stereotactic Body Radiation Therapy With Focal Boost to Magnetic Resonance Imaging-Identified Prostate Cancer Lesions: Results of a Phase 2 Trial

PURPOSE

In this prospective phase 2 trial, we investigated the toxicity and patient-reported quality-of-life outcomes in patients treated with stereotactic body radiation therapy (SBRT) to the prostate gland and a simultaneous focal boost to magnetic resonance imaging (MRI)-identified intraprostatic lesions while also de-escalating dose to the adjacent organs at risk.

METHODS AND MATERIALS

Eligible patients included low- or intermediate-risk prostate cancer (Gleason score ≤7, prostate specific antigen ≤20, T stage ≤2b). SBRT was prescribed to 40 Gy in 5 fractions delivered every other day to the prostate, with any areas of high disease burden (MRI-identified prostate imaging reporting and data system 4 or 5 lesions) simultaneously escalated to 42.5 to 45 Gy and areas overlapping organs at risk (within 2 mm of urethra, rectum, and bladder) constrained to 36.25 Gy (n = 100). Patients without a pretreatment MRI or without MRI-identified lesions were treated to dose of 37.5 Gy with no focal boost (n = 14).

RESULTS

From 2015 to 2022, a total of 114 patients were enrolled with a median follow-up of 42 months. No acute or late grade 3+ gastrointestinal (GI) toxicity was observed. One patient developed late grade 3 genitourinary (GU) toxicity at 16 months. In patients treated with focal boost (n = 100), acute grade 2 GU and GI toxicity was seen in 38% and 4% of patients, respectively. Cumulative late grade 2+ GU and GI toxicities at 24 months were 13% and 5% respectively. Patient-reported outcomes showed no significant long-term change from baseline in urinary, bowel, hormonal, or sexual quality-of-life scores after treatment.

CONCLUSIONS

SBRT to a dose of 40 Gy to the prostate gland with a simultaneous focal boost up to 45 Gy is well tolerated with similar rates of acute and late grade 2+ GI and GU toxicity as seen in other SBRT regimens without intraprostatic boost. Moreover, no significant long-term changes were seen in patient-reported urinary, bowel, or sexual outcomes from pretreatment baseline.

Sustained Preservation of Cognition and Prevention of Patient-Reported Symptoms With Hippocampal Avoidance During Whole-Brain Radiation Therapy for Brain Metastases: Final Results of NRG Oncology CC001

PURPOSE

Initial report of NRG Oncology CC001, a phase 3 trial of whole-brain radiation therapy plus memantine (WBRT + memantine) with or without hippocampal avoidance (HA), demonstrated neuroprotective effects of HA with a median follow-up of fewer than 8 months. Herein, we report the final results with complete cognition, patient-reported outcomes, and longer-term follow-up exceeding 1 year.

METHODS AND MATERIALS

Adult patients with brain metastases were randomized to HA-WBRT + memantine or WBRT + memantine. The primary endpoint was time to cognitive function failure, defined as decline using the reliable change index on the Hopkins Verbal Learning Test-Revised (HVLT-R), Controlled Oral Word Association, or the Trail Making Tests (TMT) A and B. Patient-reported symptom burden was assessed using the MD Anderson Symptom Inventory with Brain Tumor Module and EQ-5D-5L.

RESULTS

Between July 2015 and March 2018, 518 patients were randomized. The median follow-up for living patients was 12.1 months. The addition of HA to WBRT + memantine prevented cognitive failure (adjusted hazard ratio, 0.74, P = .016) and was associated with less deterioration in TMT-B at 4 months (P = .012) and HVLT-R recognition at 4 (P = .055) and 6 months (P = .011). Longitudinal modeling of imputed data showed better preservation of all HVLT-R domains (P < .005). Patients who received HA-WBRT + Memantine reported less symptom burden at 6 (P < .001 using imputed data) and 12 months (P = .026 using complete-case data; P < .001 using imputed data), less symptom interference at 6 (P = .003 using complete-case data; P = .0016 using imputed data) and 12 months (P = .0027 using complete-case data; P = .0014 using imputed data), and fewer cognitive symptoms over time (P = .043 using imputed data). Treatment arms did not differ significantly in overall survival, intracranial progression-free survival, or toxicity.

CONCLUSIONS

With median follow-up exceeding 1 year, HA during WBRT + memantine for brain metastases leads to sustained preservation of cognitive function and continued prevention of patient-reported neurologic symptoms, symptom interference, and cognitive symptoms with no difference in survival or toxicity.

MET Inhibitor Capmatinib Radiosensitizes MET Exon 14-Mutated and MET-Amplified Non-Small Cell Lung Cancer

Purpose

The objective of this study was to investigate the effects of inhibiting the MET receptor with capmatinib, a potent and clinically relevant ATP-competitive tyrosine kinase inhibitor, in combination with radiation in MET exon 14-mutated and MET-amplified non-small cell lung (NSCLC) cancer models.

Methods and Materials

In vitro effects of capmatinib and radiation on cell proliferation, colony formation, MET signaling, apoptosis, and DNA damage repair were evaluated. In vivo tumor responses were assessed in cell line xenograft and patient-derived xenograft models. Immunohistochemistry (IHC) was used to confirm in vitro results.

Results

In vitro clonogenic survival assays demonstrated radiosensitization with capmatinib in both MET exon 14-mutated and MET-amplified NSCLC cell lines. No radiation-enhancing effect was observed in MET wild-type NSCLC and human bronchial epithelial cell line. Minimal apoptosis was detected with the combination of capmatinib and radiation. Capmatinib plus radiation compared to radiation alone resulted in inhibition of DNA double-strand break repair as measured by prolonged expression of γH2AX. In vivo, the combination of capmatinib and radiation significantly delayed tumor growth compared to vehicle control, capmatinib alone, or radiation alone. IHC indicated inhibition of phospho-MET and phospho-S6 and a decrease in Ki67 with inhibition of MET.

Conclusions

Inhibition of MET with capmatinib enhanced the effect of radiation in both MET exon 14-mutated and MET-amplified NSCLC models.

Treatment Efficacy Outcomes Combining Dual Checkpoint Immunotherapy with Ablative Radiation to All Sites of Oligometastatic Non-Small Cell Lung Cancer: Survival Analysis of a Phase IB trial

PURPOSE/OBJECTIVE(S)

Aggressivelocal treatment to a limited number of metastatic sites in patients with oligometastatic NSCLC increases progression free survival (PFS) and overall survival (OS). Prior studies have shown the safety of combining high dose stereotactic body radiation therapy (SBRT) with single agent anti-PD1/PD-L1 therapy. Here, we report secondary survival endpoint outcomes from a phase Ib clinical trial investigating the safety of combining ablative, high dose radiation with dual checkpoint, anti-CTLA-4 and anti-PD-L1 immunotherapy for patients with oligometastatic NSCLC.

MATERIALS/METHODS

Patients with up to 6 sites of extracranial metastatic disease were eligible for trial enrollment. All sites of disease were treated with stereotactic body radiation therapy to a dose of 30 - 50 Gy in 5 fractions. Dual checkpoint immunotherapy was started 7 days following completion of radiation utilizing anti-CTLA-4 (Tremelimumab) and anti-PD-L1 (Durvalumab) immunotherapy for a total of four cycles followed by durvalumab alone until dose limiting toxicity or progression was observed. Primary toxicity outcomes were previously reported. Progression free and overall survival was analyzed using Kaplan Meier statistical methods.

RESULTS

Fifteen patients were treated with SBRT and received at least one dose of dual agent immunotherapy per protocol. The median follow up was 43 months. The median number of extracranial metastatic sites was 2. Seven patients had 3 or more sites of extracranial disease. The most commonly treated sites were separate metastatic pulmonary lesions or osseous metastatic lesions. Median progression free survival (PFS) was 42 months and median overall survival (OS) was 48 months. Seven patients remain alive without evidence of progressive disease. Prior history of brain metastases was associated with significantly worse PFS (Median PFS 4 months vs 42 months, HR 6.1 (95% CI 1.6 - 37.0) p = 0.0248), but no difference in OS (Median OS 24 vs 42 months, HR 1.9 (95% CI 0.3 - 10.4).

CONCLUSION

Ablative SBRT radiation to up to 6 sites of disease followed by dual checkpoint immunotherapy in oligometastatic NSCLC resulted in a favorable progression free survival (42 months) and overall survival (48 months) compared to historical controls. These findings suggest potential benefit to patient outcomes compared to immunotherapy or radiation alone in this patient population and warrant further investigation.

Leveraging Quantitative Imaging and Machine Learning to Differentiate Radionecrosis from Disease Recurrence in Patients with Brain Metastases

PURPOSE/OBJECTIVE(S)

Radiation necrosis can be difficult to non-invasively discern from tumor progression after stereotactic radiosurgery (SRS). In this work, we investigate the utility of radiomics (computerized features) and machine learning to capture per-voxel lesion heterogeneity on routine MRI scans, to differentiate radionecrosis from tumor recurrence in patients with brain metastases treated with SRS.

MATERIALS/METHODS

A retrospective analysis was conducted of patients with brain metastases treated with SRS. Eighty-three lesions (n = 56 intact; n = 27 surgical cavity) from 69 patients were identified with median age 68.8 years (range 40.2 - 91.0), of whom 53.6% were male and 33.3% received prior whole-brain radiotherapy (WBRT). Lesion histology included lung (60.2%), renal cell (15.7%), melanoma (10.8%), breast (9.6%), and other (3.6%). Pathologic confirmation was available in 73.5% of lesions. Both intact and resection cavity lesions were included and individually segmented. Image preprocessing and radiomic feature extraction were done using ANTsPy and open-source software. A total of 210 features were extracted from post-contrast T1-weighted (T1w) and T2/FLAIR MRIs. Highly correlated features were removed. Univariate logistic regression was conducted on the remaining T1w and T2/FLAIR features as well as on clinical variables. Multivariate analysis was implemented with various classifiers (Random Forest, Ridge, Lasso, Support Vector Machine [SVM]) on the top-performing features found on univariate logistic regression. Models were assessed using cross-validation to select the best model by area under ROC curve (AUC). Specificity and sensitivity were calculated.

RESULTS

On univariate analysis, the top 10 radiomics features consisted of 6 T1w features and 4 T2/FLAIR features (4 GLCM, 3 first order, 1 GLSZM, 1 GLRLM, and 1 shape feature). Age, gender, disease site, prior WBRT, prior fractionated SRS, planning tumor volume, brain-GTV V12 Gy, and immunotherapy before or after SRS were not predictive (AUC less than 62.0%) on univariate analysis compared to radiomic features. Multivariate analysis of top performing radiomic features on both intact and surgical cavities yielded an AUC of 72.0% (standard deviation [SD] ±8.8%). Multivariate analysis of top features on intact lesions alone improved the AUC to 80.5% (SD ±10.8%), with sensitivity of 77.8%, specificity of 72.4%, and positive likelihood ratio of 2.82 in differentiating radionecrosis from recurrence.

CONCLUSION

Radiomics and machine learning tools may improve diagnostic ability of distinguishing radiation necrosis from tumor recurrence after SRS. Further work is needed to deploy this in a larger multi-institutional cohort and prospectively evaluate its efficacy as a decision-support tool to personalize care in patients with brain metastases.

Initial Results of a Phase II Trial of Hypofractionated Radiation Therapy for Inoperable Soft Tissue Sarcoma

PURPOSE/OBJECTIVE(S)

For patients with soft tissue sarcoma (STS) who cannot or choose not to have surgery, radiation can provide local tumor control in both palliative and definitive settings. Conventionally fractionated radiation provides modest (< 50%) rates of local control (LC) for STS at 2 years. To our knowledge, no prospective studies to date have evaluated the safety and efficacy of dose-escalated hypofractionated radiation therapy as treatment of inoperable STS. We hypothesized that dose-escalated, hypofractionated radiation therapy (RT) for inoperable STS could achieve higher rates of LC than reported in trials of conventionally fractionated RT.

MATERIALS/METHODS

An IRB-approved single institution prospective phase II clinical trial of dose-escalated, hypofractionated RT as local control for STS was designed and completed planned accrual. Exclusion criteria included anti-cancer systemic therapy within the preceding two weeks. Patients underwent hypofractionated RT utilizing either CT-guided radiation (24, 50%) or MRI-guided radiation treatments (24, 50%). Data on patient characteristics, RT dose and fractionation, LC, toxicity, and overall survival (OS) was collected. The primary endpoint was local tumor control (stable, partial, or complete response according to RECIST) at 2-years after completion of radiation. Secondary endpoints were acute and late toxicity, rates of complete response, 5-year local tumor control, and progression-free and overall survival. Acute toxicity was graded on the Common Terminology Criteria for Adverse Events (CTCAE) v5.0 scale during treatment and at 3 months following RT.

RESULTS

Forty-eight patients were enrolled, 17 with non-metastatic localized disease and 31 with metastatic disease. Median patient age was 64. Twenty-five men and 23 women were treated. Ninety-six total lesions were treated (36 lung, 7 extremity, 37 abdominopelvic, 16 other). Radiation dose per fraction ranged from 6-12 Gy for a total of 1-12 fractions (median dose was 52.5 Gy in 6 fractions. Median patient follow-up is 8.6 months (range 1 - 36 months). Six patients (13%) did not complete initial 3-month follow-up imaging. Of the 40 patients who have undergone 3-month follow up imaging, 32 (80%) had stable disease, 5 (12.5%) had partial response, 0 had complete response, and 3 (7.5%) had disease progression. Median PFS was 17.2 months at time of last follow up. Median OS was 12.9 months at time of last follow up. Twenty-five patients (52%) experienced an acute toxicity likely or possibly related to radiation. Three (6%) patients experienced CTACE grade 3 or greater treatment-related toxicity (pain, weakness, decreased range of motion, dermatitis).

CONCLUSION

In this initial report of a prospective, single-institution clinical trial of hypofractionated RT for STS not undergoing resection, we report low rates of acute grade 3 or greater toxicity and high rates of tumor response. We will continue to follow these patients to assess late toxicity and durability of tumor control.

Longitudinal Radiomics-Based Prediction of Local Recurrence after Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer

PURPOSE/OBJECTIVE(S)

Computed tomography (CT)-based radiomic analysis is an emerging tool that can help predict recurrence after radiation in non-small cell lung cancer (NSCLC). Most studies have focused on using radiomic features obtained from pre-treatment CT scans but not on post-treatment CTs. Our goal was to determine if radiomic features derived from post-treatment CTs perform better than those from pre-treatment CTs in predicting local recurrence after stereotactic body radiation therapy (SBRT) in patients with early-stage NSCLC.

MATERIALS/METHODS

Patients with T1/T2 N0 early-stage NSCLC were retrospectively reviewed. Criteria for selection included patients with biopsy-proven NSCLC, non-ground glass solid lesions, 4-5 fraction SBRT treatments, and non-contrast thin-slice CTs available at pre-treatment baseline and at 3 and 6 months post-SBRT. Clinical and tumor characteristics were compared using Chi-square and Student's t-tests. CT image pre-processing was performed and 107 radiomic features were extracted using 3D Slicer and open-source software. Univariate analysis for local recurrence was determined by Cox regression with death as a competing risk. The Benjamini-Hochberg Procedure was applied to control the false discovery rate. Pearson correlation analysis was used to exclude redundant features (r > 0.8), and multivariate analysis was conducted with Random Forest on the top-performing features found on univariate logistic regression. Models were trained on a class-balanced loss to account for class imbalance. Twenty iterations of stratified 3 k-fold cross-validation were used to select the best model by the area under the receiver operating characteristic curve (AUC).

RESULTS

We identified and analyzed 86 patient tumors, including 76 non-local recurrences and 10 local recurrences (49 males, 37 females; age, median 72, range 52-91 years). No differences in age, histology, standardized uptake values on positron emission tomography scans, gross tumor volume, and radiation dose were found between patients with and without local recurrence (all p >0.05). The median time to local recurrence was 18.9 months (range 5.5-45.6 months). At the baseline, 3-month, and 6-month timepoints, 2, 10, and 10 radiomic features predicted local recurrence on Cox regression univariate analysis, respectively (all q <0.01). On multivariate analysis of top-performing radiomic features, the 3-month timepoint performed the best with a mean (±standard deviation) AUC score of 0.82 (±0.13) compared to a mean AUC of 0.73 (±0.086) at baseline and a mean AUC of 0.74 (±0.10) at 6 months.

CONCLUSION

Post-treatment radiomic features at 3 months outperformed pre-treatment radiomic features in predicting local recurrence after SBRT for NSCLC. These results suggest radiomic data from follow-up CTs may be helpful when developing radiomic models to predict local recurrence in patients with NSCLC.

Metrics of dose to highly ventilated lung are predictive of radiation-induced pneumonitis in lung cancer patients

PURPOSE

To identify metrics of radiation dose delivered to highly ventilated lung that are predictive of radiation-induced pneumonitis.

METHODS AND MATERIALS

A cohort of 90 patients with locally advanced non-small cell lung cancer treated with standard fractionated radiation therapy (RT) (60-66 Gy in 30-33 fractions) were evaluated. Regional lung ventilation was determined from pre-RT 4-dimensional computed tomography (4DCT) using the Jacobian determinant of a B-spline deformable image registration to estimate lung tissue expansion during respiration. Multiple voxel-wise population- and individual-based thresholds for defining high functioning lung were considered. Mean dose and volumes receiving dose ≥ 5-60 Gy were analyzed for both total lung-ITV (MLD,V5-V60) and highly ventilated functional lung-ITV (fMLD,fV5-fV60). The primary endpoint was symptomatic grade 2+ (G2+) pneumonitis. Receiver operator curve (ROC) analyses were used to identify predictors of pneumonitis.

RESULTS

G2+ pneumonitis occurred in 22.2% of patients, with no differences between stage, smoking status, COPD, or chemo/immunotherapy use between G<2 and G2+ patients (P≥ 0.18). Highly ventilated lung was defined as voxels exceeding the population-wide median of 18% voxel-level expansion. All total and functional metrics were significantly different between patients with and without pneumonitis (P≤ 0.039). Optimal ROC points predicting pneumonitis from functional lung dose were fMLD ≤ 12.3 Gy, fV5 ≤ 54% and fV20 ≤ 19 %. Patients with fMLD ≤ 12.3 Gy had a 14% risk of developing G2+ pneumonitis whereas risk significantly increased to 35% for those with fMLD > 12.3 Gy (P = 0.035).

CONCLUSIONS

Dose to highly ventilated lung is associated with symptomatic pneumonitis and treatment planning strategies should focus on limiting dose to functional regions. These findings provide important metrics to be used in functional lung avoidance RT planning and designing clinical trials.

Abstract 207: MET inhibition enhances the effect of radiation in MET mutated non-small cell lung cancer brain metastasis patient derived xenografts

Objective: The MET receptor is mutated in 3-4% and amplified in 1-6% of patients with non-small cell lung cancer. The most common MET mutation is in exon 14, which results in deletion of the intracellular juxtamembrane domain of the receptor, leading to enhanced signaling. Mutation at Asp-1000 in the juxtamembrane region has also been reported and can lead to inhibition of apoptosis and cell proliferation. MET is involved in multiple pathways associated with radiation response. Therefore, we investigated the effects of inhibiting MET in combination with radiation in two preclinical non-small cell lung cancer (NSCLC) brain metastasis patient derived xenograft (PDX) models.

Methods: Surgically obtained tissue was implanted subcutaneously into immunodeficient mice. Histology and DNA loci were compared between original tumor and PDX. DNA sequencing was performed on tumors for mutation analysis. In vivo growth responses to the MET inhibitor capmatinib or savolitinib with and without radiation were assessed. Radiation was delivered in 10 daily fractions of 2 Gy. Drug was administered by oral gavage daily 1 hour prior to radiation at a dose of 2.5 mg/kg for savaolitnib or 20 mg/kg for capmatinib for 10 days. Immunohistochemistry (IHC) was performed to evaluate MET signaling and proliferation.

Results: PDXs were successfully established from two patients with MET mutated NSCLC brain metastases: a lung adenocarcinoma with a MET exon 14 skipping mutation and a lung sarcomatoid carcinoma with adenocarcinoma component with an Asp-1000 frameshift mutation. Morphologically, strong retention of cytoarchitectural features was observed between original patient tumors and PDXs. Short tandem repeat analysis confirmed 100% matching of alleles between patient tumors and PDXs. DNA sequencing confirmed METex14 and MET Asp-1000 frameshift mutation. In the METex14 PDX, savolitinib alone significantly inhibited tumor growth with a growth inhibition value of 46% (p&lt;0.01). Combination of savolitinib and radiation significantly delayed growth compared to vehicle control, savolitinib alone or radiation alone (p&lt;0.001). The absolute growth delay was 42.4 days for savolitinib plus radiation treatment compared to 9.3 days for savolitinib alone and 28.2 days for irradiation. In the MET Asp-1000 PDX, capmatinib and radiation significantly delayed growth compared the other treatment arms (p&lt;0.01). IHC demonstrated inhibition of phospho-MET and pS6 and a decrease in Ki67 with MET inhibition.

Conclusion: Inhibition of MET enhanced the effect of radiation in our two preclinical in vivo MET mutated NSCLC brain metastasis models. Additional studies are currently underway evaluating the mechanisms of radiation sensitization and the efficacy of this combination in MET amplified PDX models.

Citation Format: Kwangok P. Nickel, Shrey Ramesh, Saahil Javeri, Nitin Somasundaram, Nan Sethakorn, Randall J. Kimple, Andrew M. Baschnagel. MET inhibition enhances the effect of radiation in MET mutated non-small cell lung cancer brain metastasis patient derived xenografts [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 207.

Radiomic Modeling of Bone Density and Rib Fracture Risk After Stereotactic Body Radiation Therapy for Early-Stage Non-Small Cell Lung Cancer

Purpose

Methods and Materials

Results

Conclusion

ATR Inhibitor M6620 (VX-970) Enhances the Effect of Radiation in Non-Small Cell Lung Cancer Brain Metastasis Patient-Derived Xenografts

M6620, a selective ATP-competitive inhibitor of the ATM and RAD3-related (ATR) kinase, is currently under investigation with radiation in patients with non-small cell lung cancer (NSCLC) brain metastases. We evaluated the DNA damage response (DDR) pathway profile of NSCLC and assessed the radiosensitizing effects of M6620 in a preclinical NSCLC brain metastasis model. Mutation analysis and transcriptome profiling of DDR genes and pathways was performed on NSCLC patient samples. NSCLC cell lines were assessed with proliferation, clonogenic survival, apoptosis, cell cycle, and DNA damage signaling and repair assays. NSCLC brain metastasis patient-derived xenograft models were used to assess intracranial response and overall survival. In vivo IHC was performed to confirm in vitro results. A significant portion of NSCLC patient tumors demonstrated enrichment of DDR pathways. DDR pathways correlated with lung squamous cell histology; and mutations in ATR, ATM, BRCA1, BRCA2, CHEK1, and CHEK2 correlated with enrichment of DDR pathways in lung adenocarcinomas. M6620 reduced colony formation after radiotherapy and resulted in inhibition of DNA DSB repair, abrogation of the radiation-induced G2 cell checkpoint, and formation of dysfunctional micronuclei, leading to enhanced radiation-induced mitotic death. The combination of M6620 and radiation resulted in improved overall survival in mice compared with radiation alone. In vivo IHC revealed inhibition of pChk1 in the radiation plus M6620 group. M6620 enhances the effect of radiation in our preclinical NSCLC brain metastasis models, supporting the ongoing clinical trial (NCT02589522) evaluating M6620 in combination with whole brain irradiation in patients with NSCLC brain metastases.

Impact of immediate cryopreservation on the establishment of patient derived xenografts from head and neck cancer patients

BACKGROUND

Patient-derived xenografts established from human cancers are important tools for investigating novel anti-cancer therapies. Establishing PDXs requires a significant investment and many PDXs may be used infrequently due to their similarity to existing models, their growth rate, or the lack of relevant mutations. We performed this study to determine whether we could efficiently establish PDXs after cryopreservation to allow molecular profiling to be completed prior to implanting the human cancer.

METHODS

Fresh tumor was split with half used to establish a PDX immediately and half cryopreserved for later implantation. Resulting tumors were assessed histologically and tumors established from fresh or cryopreserved tissues compared as to the growth rate, extent of tumor necrosis, mitotic activity, keratinization, and grade. All PDXs were subjected to short tandem repeat testing to confirm identity and assess similarity between methods.

RESULTS

Tumor growth was seen in 70% of implanted cases. No growth in either condition was seen in 30% of tumors. One developed a SCC from the immediate implant but a lymphoproliferative mass without SCC from the cryopreserved specimen. No difference in growth rate was seen. No difference between histologic parameters was seen between the two approaches.

CONCLUSIONS

Fresh human cancer tissue can be immediately cryopreserved and later thawed and implanted to establish PDXs. This resource saving approach allows for tumor profiling prior to implantation into animals thus maximizing the probability that the tumor will be utilized for future research.

Development and characterization of patient-derived xenografts from non-small cell lung cancer brain metastases

Non-small cell lung cancer (NSCLC) brain metastasis cell lines and in vivo models are not widely accessible. Herein we report on a direct-from patient-derived xenograft (PDX) model system of NSCLC brain metastases with genomic annotation useful for translational and mechanistic studies. Both heterotopic and orthotopic intracranial xenografts were established and RNA and DNA sequencing was performed on patient and matching tumors. Morphologically, strong retention of cytoarchitectural features was observed between original patient tumors and PDXs. Transcriptome and mutation analysis revealed high correlation between matched patient and PDX samples with more than more than 95% of variants detected being retained in the matched PDXs. PDXs demonstrated response to radiation, response to selumetinib in tumors harboring KRAS G12C mutations and response to savolitinib in a tumor with MET exon 14 skipping mutation. Savolitinib also demonstrated in vivo radiation enhancement in our MET exon 14 mutated PDX. Early passage cell strains showed high consistency between patient and PDX tumors. Together, these data describe a robust human xenograft model system for investigating NSCLC brain metastases. These PDXs and cell lines show strong phenotypic and molecular correlation with the original patient tumors and provide a valuable resource for testing preclinical therapeutics.

Combined Immunotherapy and Stereotactic Radiotherapy Improves Neurologic Outcomes in Patients with Non-small-cell Lung Cancer Brain Metastases

BACKGROUND

The purpose of this study was to compare the outcomes of patients with non-small cell lung cancer (NSCLC) brain metastases treated with stereotactic radiotherapy (SRT) alone versus SRT and immune checkpoint inhibitors (ICIs).

PATIENTS AND METHODS

Patients treated for their first diagnosis of intracranial metastases with SRT or SRT plus ICI were retrospectively identified. Overall survival (OS), local control (LC), distant brain failure (DBF), neurologic death, and rates of radiation necrosis were calculated. Univariate (UVA) and multivariable (MVA) analyses with competing risk analysis were performed.

RESULTS

Seventy-seven patients with 132 lesions were analyzed, including 44 patients with 68 lesions in the SRT group and 33 patients with 64 lesions in the SRT plus ICI group. There were no differences in baseline factors between groups. Use of ICI predicted for decreased DBF (hazard ratio [HR], 0.45; 95% confidence interval [CI], 0.24-0.84; P = .01), decreased rates of neurologic death (HR, 0.29; 95% CI, 0.10-0.85; P = .02), and better OS (HR, 0.46; 95% CI, 0.23-0.91; P = .03). Two-year LC was 97% for the SRT + ICI group, and 86% for the SRT-alone group (P = .046). Actuarial 2-year DBF was 39% for the SRT + ICI group and 66% for the SRT alone group (P = .016). On MVA, ICI use persisted in predicting lower incidence of neurologic death (HR, 0.25; 95% CI, 0.09-0.72; P = .01) and DBF (HR, 0.47; 95% CI, 0.25-0.85; P = .01) when adjusted for competing risk of death.

CONCLUSION

In this cohort of patients with NSCLC brain metastases, ICI use combined with SRT predicted for improved LC and OS and decreased DBF and risk of neurologic death.

FGFR Inhibition Enhances Sensitivity to Radiation in Non-Small Cell Lung Cancer

FGFRs are commonly altered in non-small cell lung cancer (NSCLC). FGFRs activate multiple pathways including RAS/RAF/MAPK, PI3K/AKT, and STAT, which may play a role in the cellular response to radiation. We investigated the effects of combining the selective FGFR 1-3 tyrosine kinase inhibitor AZD4547 with radiation in cell line and xenograft models of NSCLC. NSCLC cell lines were assessed with proliferation, clonogenic survival, apoptosis, autophagy, cell cycle, and DNA damage signaling and repair assays. In vivo xenografts and IHC were used to confirm in vitro results. NSCLC cell lines demonstrated varying degrees of FGFR protein and mRNA expression. In vitro clonogenic survival assays showed radiosensitization with AZD4547 in two NSCLC cell lines. In these two cell lines, an increase in apoptosis and autophagy was observed with combined radiation and AZD4547. The addition of AZD4547 to radiation did not significantly affect γH2AX foci formation. Enhanced xenograft tumor growth delay was observed with the combination of radiation and AZD4547 compared with radiation or drug alone. IHC results revealed inhibition of pMAPK and pS6 and demonstrated an increase in apoptosis in the radiation plus AZD4547 group. This study demonstrates that FGFR inhibition by AZD4547 enhances the response of radiation in FGFR-expressing NSCLC in vitro and in vivo model systems. These results support further investigation of combining FGFR inhibition with radiation as a clinical therapeutic strategy.

Fibroblast Growth Factor Receptors as Targets for Radiosensitization in Head and Neck Squamous Cell Carcinomas

PURPOSE

We examined the capacity of the pan-fibroblast growth factor receptor (FGFR) inhibitor AZD4547 to augment radiation response across a panel of head and neck squamous cell carcinoma (HNSCC) cell lines and xenografts.

METHODS AND MATERIALS

FGFR1, FGFR2, and FGFR3 RNA in situ hybridization expression was assessed in a cohort of HNSCC patient samples, cell lines, and patient-derived xenografts (PDXs). In vitro effects of AZD4547 and radiation on cell survival, FGFR signaling, apoptosis, autophagy, cell cycle, and DNA damage repair were evaluated. Reverse phase protein array was used to identify differentially phosphorylated proteins in cells treated with AZD4547. In vivo tumor responses were evaluated in cell lines and PDX models.

RESULTS

FGFR1, FGFR2, and FGFR3 RNA in situ hybridization were expressed in 41%, 81%, and 89% of 107 oropharynx patient samples. Sensitivity to AZD4547 did not directly correlate with FGFR protein or RNA expression. In sensitive cell lines, AZD4547 inhibited p-MAPK in a time-dependent manner. Significant radiosensitization with AZD4547 was observed in cell lines that were sensitive to AZD4547. The mechanism underlying these effects appears to be multifactorial, involving inhibition of the MTOR pathway and subsequent enhancement of autophagy and activation of apoptotic pathways. Significant tumor growth delay was observed when AZD4547 was combined with radiation compared with radiation or drug alone in an FGFR-expressing HNSCC cell line xenograft and PDX.

CONCLUSIONS

These findings suggest that AZD4547 can augment the response of radiation in FGFR-expressing HNSCC in vivo model systems. FGFR1 and FGFR2 may prove worthy targets for radiosensitization in HNSCC clinical investigations.

Prognostic factors and outcome of reirradiation for locally recurrent small cell lung cancer-a multicenter study

Background

The prognosis of patients with recurrent small cell lung cancer (SCLC) remains poor and treatment options are limited. We performed a multi-institution retrospective cohort study to evaluate the outcome of thoracic reirradiation, identify prognostic factors and assess treatment-related toxicity.

Methods

Data of 33 patients re-irradiated for recurrent SCLC at 4 international university hospitals, were analysed. Overall survival (OS) acute and late toxicities were evaluated and prognostic factors for reirradiation were identified.

Results

Reirradiation (Re-RT) was performed at a median interval time of 24 months after the first thoracic radiotherapy series. Median survival after reirradiation was 7 months (range, 1-54 months). The Re-RT dose in EQD2 ranged from 20 to 87.50 Gy with a median of 32.50 Gy. The 1- and 2-year OS were 33% and 17%, respectively. Patients with a good performance status (KPS >70%), absence of extrathoracic disease, reirradiation dose (EQD2) of >40 Gy and a cumulative dose of first plus second series of radiotherapy (EQD2) >90 Gy were associated with improved OS. Acute pulmonary Grade 1-2 toxicity from re-irradiation was recorded in 11 patients (33%) and grade 3 acute toxicity was encountered 1 patient (3%).

Conclusions

Reirradiation for locoregionally recurrent SCLC is safe and shows promising outcomes. Patients reirradiated with doses >40 Gy experienced more favourable survival rates. In contrast, patients with a poor performance status or extrathoracic disease have a poor prognosis and Re-RT should be considered only for symptom control in this group.

Predictors of radiation necrosis in long-term survivors after Gamma Knife stereotactic radiosurgery for brain metastases

Background

The long-term risk of necrosis after radiosurgery for brain metastases is uncertain. We aimed to investigate incidence and predictors of radiation necrosis for individuals with more than 1 year of survival after radiosurgery for brain metastases.

Methods

Patients who had a diagnosis of brain metastases treated between December 2006 and December 2014, who had at least 1 year of survival after first radiosurgery were retrospectively reviewed. Survival was analyzed using the Kaplan-Meier estimator, and the incidence of radiation necrosis was estimated with death or surgical resection as competing risks. Patient and treatment factors associated with radiation necrosis were also analyzed.

Results

A total of 198 patients with 732 lesions were analyzed. Thirty-four lesions required salvage radiosurgery and 10 required salvage surgical resection. Median follow-up was 24 months. The estimated median survival for this population was 25.4 months. The estimated per-lesion incidence of radiation necrosis at 4 years was 6.8%. Medical or surgical therapy was required for 60% of necrosis events. Tumor volume and male sex were significant factors associated with radiation necrosis. The per-lesions incidence of necrosis for patients undergoing repeat radiosurgery was 33.3% at 4 years.

Conclusions

In this large series of patients undergoing radiosurgery for brain metastases, patients continued to be at risk for radiation necrosis throughout their first 4 years of survival. Repeat radiosurgery of recurrent lesions greatly exacerbates the risk of radiation necrosis, whereas treatment of larger target volumes increases the risk modestly.

Prognostic significance of MTOR expression in HPV positive and negative head and neck cancers treated by chemoradiation

BACKGROUND

The mechanistic target of rapamycin (MTOR) plays a key role in regulating cell growth and metabolism and is commonly overexpressed in head and neck cancer (HNSCC). This study investigated the association of MTOR with clinical outcome in human papilloma virus (HPV) positive and negative HNSCC patients treated by chemoradiation.

METHODS

A tissue microarray (TMA) consisting of cores from 109 HNSCC patients treated by definitive chemoradiation was constructed and stained with antibodies against p16 and MTOR and expression correlated with clinicopathological features and clinical outcome.

RESULTS

MTOR varied widely between tumor cores and was not associated with HPV status or clinicopathological features. There was a positive correlation with pre-treatment FDG uptake. (P = .01). In HPV negative patients, MTOR predicted for shorter locoregional control (P = .02), diseases free survival (P = .02), and overall survival (P = .04). MTOR expression was not associated with outcome in HPV positive patients.

CONCLUSIONS

Prognostic significance of MTOR expression depends on HPV status.

MR-based treatment planning in radiation therapy using a deep learning approach

Purpose

To develop and evaluate the feasibility of deep learning approaches for MR‐based treatment planning (deepMTP) in brain tumor radiation therapy.

Methods and materials

A treatment planning pipeline was constructed using a deep learning approach to generate continuously valued pseudo CT images from MR images. A deep convolutional neural network was designed to identify tissue features in volumetric head MR images training with co‐registered kVCT images. A set of 40 retrospective 3D T1‐weighted head images was utilized to train the model, and evaluated in 10 clinical cases with brain metastases by comparing treatment plans using deep learning generated pseudo CT and using an acquired planning kVCT. Paired‐sample Wilcoxon signed rank sum tests were used for statistical analysis to compare dosimetric parameters of plans made with pseudo CT images generated from deepMTP to those made with kVCT‐based clinical treatment plan (CTTP).

Results

deepMTP provides an accurate pseudo CT with Dice coefficients for air: 0.95 ± 0.01, soft tissue: 0.94 ± 0.02, and bone: 0.85 ± 0.02 and a mean absolute error of 75 ± 23 HU compared with acquired kVCTs. The absolute percentage differences of dosimetric parameters between deepMTP and CTTP was 0.24% ± 0.46% for planning target volume (PTV) volume, 1.39% ± 1.31% for maximum dose and 0.27% ± 0.79% for the PTV receiving 95% of the prescribed dose (V95). Furthermore, no significant difference was found for PTV volume (P = 0.50), the maximum dose (P = 0.83) and V95 (P = 0.19) between deepMTP and CTTP.

Conclusions

We have developed an automated approach (deepMTP) that allows generation of a continuously valued pseudo CT from a single high‐resolution 3D MR image and evaluated it in partial brain tumor treatment planning. The deepMTP provided dose distribution with no significant difference relative to a kVCT‐based standard volumetric modulated arc therapy plans.

Abstract 2924: Evaluation of the pan-FGFR inhibitor AZD4547 with radiation in non-small cell lung cancer

Objective: The fibroblast growth factor receptors (FGFR) are commonly altered in non-small cell lung cancer (NSCLC), including high level of amplification of FGFR1 in lung squamous cell carcinoma. FGFR signaling may play a role in the response to radiation. We investigated the radiosensitizing effects of the selective tyrosine kinase inhibitor AZD4547 in a NSCLC model using cell lines and tumor xenografts.

Methods: A panel of six NSCLC cell lines were screened for FGFR1/2 DNA amplification, RNA expression, and protein expression. All cells were assessed for in vitro response to AZD4547. Immunoblots were used to examine the effect of AZD4547 on downstream signaling proteins. Apoptosis was measured by Annexin V staining and autophagy with acridine orange assay. Radiation clonogenic survival assays and xenograft growth delays experiments were performed to investigate radiosensitization. In vivo mechanistic studies were conducted using immunohistochemistry.

Results: Cell lines demonstrated varying degree of FGFR1/2 RNA and protein expression. In sensitive cell lines, AZD4547 inhibited p-MAPK in a time dependent manner. In vitro clonogenic survival assays showed robust radiosensitivity with AZD4547 in three out of six NSCLC cell lines. All three cell lines overexpressed FGFR1 and two of the cells had high FGFR1 copy number. There was no radiosensitization seen in an immortalized normal human bronchial epithelial cell line. A significant increase in autophagy and apoptosis was observed with combined radiation and AZD4547. Significant tumor growth delay was observed with the administration of radiation and AZD4547 compared to radiation or drug alone in two NSCLC xenograft tumor models. IHC analysis revealed modulation of FGFR-downstream signaling (p-Erk and p-S6) and proliferative (Ki67) and apoptotic markers (Cleaved Caspace 3).

Conclusion: These findings suggest that AZD4547 can augment the response of radiation in NSCLC model systems. FGFR1 and FGFR2 expression may be a potential targets for radiosensitization in NSCLC. Additional studies are underway to understand the mechanism of radiosensitization.

Citation Format: Margot Miller, Michael Fisher, Gopika Senthilkumar, Saakshi Kaushik, Lindsey Able, Sean Brennan, Gopal Iyer, Randall Kimple, Andrew M. Baschnagel. Evaluation of the pan-FGFR inhibitor AZD4547 with radiation in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2924.

Abstract 2929: Radiosensitization of head and neck cancer by FGFR inhibition

Objective:

Fibroblast growth factor receptors are frequently amplified or overexpressed in head and neck squamous cell carcinomas (HNSCC). We assessed the potential of a selective FGFR-kinase inhibitor, AZD4547, to act as a radiosensitizer in head and neck cancer cell lines and xenografts.

Methods:

A panel of head and neck cancer (n=10) and normal oral mucosa (HTE) cell lines were screened for FGFR1, 2, and 3 gene copy number, RNA expression, and protein. Sensitivity to the FGFR inhibitor AZD4547, alone or in combination with radiation, was assessed using proliferation and clonogenic survival assays. Putative mechanisms of radiosensitization were investigated by immunoblot and by assessing for DNA repair capacity, cell cycle effects, apoptosis, senescence, and autophagy. Tumor response of cell line xenografts and patient derived xenografts was assessed in vivo.

Results:

Cells demonstrated varying responses to FGFR inhibition but this did not correlate with FGFR gene copy number, mRNA expression, or protein expression. Three cell lines which responded to AZD4547 alone (CCL30, Tu-138, and SCC6) were selected for further investigation. TU-138 and CCL30 featured high FGFR expression and were radiosensitized by AZD4547 in vitro. SCC6 was not. Cell lines which were insensitive to FGFR inhibition (including HTE) did not demonstrate radiosensitization by AZD4547. In the sensitive cell lines, enhanced p-MAPK inhibition was seen in a time-dependent manner following drug treatment. When added to radiation, AZD4547 resulted in increased apoptosis, autophagy, and senescence but did not alter the kinetics of DNA repair as assessed by resolution of gH2AX foci. No difference in the cell cycle distribution for irradiated cells treated with or without the addition of AZD4547 was seen. Treatment of two in vivo tumor xenografts with AZD4547 and radiation showed significant delay in tumor growth compared to treatment with radiation or drug alone.

Conclusion:

Our findings indicate that AZD4547 can augment the response of FGFR expressing HNSCC to radiation both in vitro and in vivo. Improved approaches to identify tumors most likely to benefit from FGFR inhibition could enable the selection of patients for combination therapy and has the potential to improve outcomes in these difficult to treat cancers.

Citation Format: Gopika SenthilKumar, Margot Miller, Michael Fisher, Sean Brennan, Saakshi Kaushik, Lindsey Able, Paul M. Harari, Gopal Iyer, Randall J. Kimple, Andrew M. Baschnagel. Radiosensitization of head and neck cancer by FGFR inhibition [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2929.

Analysis of the 2017 American Society for Radiation Oncology (ASTRO) Research Portfolio

PURPOSE

Research in radiation oncology (RO) is imperative to support the discovery of new uses of radiation and improvement of current approaches to radiation delivery and to foster the continued evolution of our field. Therefore, in 2016, the American Society of Radiation Oncology performed an evaluation of research grant funding for RO.

METHODS AND MATERIALS

Members of the Society of Chairs of Academic Radiation Oncology Programs (SCAROP) were asked about funded and unfunded grants that were submitted by their departments between the fiscal years 2014 and 2016. Grants were grouped according to broad categories defined by the 2017 American Society of Radiation Oncology Research Agenda. Additionally, active grants in the National Institutes of Health (NIH) Research Portfolio Online Reporting Tools database were collated using RO faculty names.

RESULTS

Overall, there were 816 funded (44%) and 1031 unfunded (56%) SCAROP-reported grants. Total grant funding was over $196 million. The US government funded the plurality (42.2%; 345 of 816) of grants compared with nonprofit and industry funders. Investigators from 10 institutions accounted for >75% of funded grants. Of the funded grants, 43.5% were categorized as "genomic influences and targeted therapies." The proportion of funded to unfunded grants was highest within the category of "tumor microenvironment, normal tissue effects, and reducing toxicity" (53.4% funded). "New clinical trial design and big data" had the smallest share of SCAROP grant applications and the lowest percent funded (38.3% of grants). NIH grants to RO researchers in 2014 to 2016 accounted for $85 million in funding. From the 31 responding SCAROP institutions, there was a 28% average success rate for RO proposals submitted to the NIH during this period.

CONCLUSIONS

Though RO researchers from responding institutions were relatively successful in obtaining funding, the overall amount awarded remains small. Continued advocacy on behalf of RO is needed, as well as investment to make research careers more attractive areas for emerging faculty.

Abstract 3946: Androgen receptor drives differential gene expression in KRAS-mediated non-small cell lung cancer

The Cancer Genome Atlas (TCGA) has identified alterations such as amplification, deletion, or mutation of androgen receptor (AR) in about 5% of human lung squamous cell carcinoma and adenocarcinoma. The expression of AR in human lung appears to play a crucial role in lung development and type II pneumocytes (PTII) maturation, but unlike in prostate cancer, the role of AR is not well known in non-small cell lung cancer (NSCLC). In our study, we demonstrated AR in NSCLC cell lines translocated into the nucleus over time when stimulated with synthetic androgen R1881, while addition of enzalutamide (MDV3100) or AR siRNA reduced AR nuclear localization. Using an NSCLC human tissue microarray also revealed that 10 out of 88 patients (11%) have positive AR immunohistochemical staining. Preliminary data from clonogenic assay indicated that enzalutamide might have radiosensitizing effect on certain NSCLC cells at 2 Gy, further suggesting the involvement of AR in lung cancer and its potential therapeutic value as a target. With the induction of R1881 for 30 minutes to 24 hours, certain NSCLC cells display decreased AR mRNA (0.5-0.8 fold), while others show modest increase (up to 1.5 fold), suggesting that AR regulation in these cells might be different due to their mutational landscapes. We then used predesigned 384 well panels from Bio-Rad to survey the effects of R1881, enzalutamide, and AR siRNA on mRNA expression levels of selected NSCLC cells. Distinct expression profiles were observed between cells that have wild-type and mutated KRAS. Taken together, these findings suggest that the AR signaling could be different based on KRAS mutational profiles of NSCLCs, and further work is required to reveal the underlying mechanism. Chromatin immunoprecipitation (ChIP) assay and RNA sequencing will be utilized to investigate AR interactions with androgen response elements and differential expressions in KRAS-driven NSCLC cells, respectively.

Citation Format: Albert Roy Wang, Hope Beyer, Sean Brennan, Shannon Stiles, Dylan Wiese, Darya Buehler, Anwaar Saeed, Andrew M. Baschnagel, Gopal Iyer. Androgen receptor drives differential gene expression in KRAS-mediated non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3946.

Precision Oncology and Genomically Guided Radiation Therapy: A Report From the American Society for Radiation Oncology/American Association of Physicists in Medicine/National Cancer Institute Precision Medicine Conference

PURPOSE

To summarize important talking points from a 2016 symposium focusing on real-world challenges to advancing precision medicine in radiation oncology, and to help radiation oncologists navigate the practical challenges of precision, radiation oncology.

METHODS AND MATERIALS

The American Society for Radiation Oncology, American Association of Physicists in Medicine, and National Cancer Institute cosponsored a meeting on precision medicine in radiation oncology. In June 2016 numerous scientists, clinicians, and physicists convened at the National Institutes of Health to discuss challenges and future directions toward personalized radiation therapy. Various breakout sessions were held to discuss particular components and approaches to the implementation of personalized radiation oncology. This article summarizes the genomically guided radiation therapy breakout session.

RESULTS

A summary of existing genomic data enabling personalized radiation therapy, ongoing clinical trials, current challenges, and future directions was collected. The group attempted to provide both a current overview of data that radiation oncologists could use to personalize therapy, along with data that are anticipated in the coming years. It seems apparent from the provided review that a considerable opportunity exists to truly bring genomically guided radiation therapy into clinical reality.

CONCLUSIONS

Genomically guided radiation therapy is a necessity that must be embraced in the coming years. Incorporating these data into treatment recommendations will provide radiation oncologists with a substantial opportunity to improve outcomes for numerous cancer patients. More research focused on this topic is needed to bring genomic signatures into routine standard of care.

A New Era of Image Guidance with Magnetic Resonance-guided Radiation Therapy for Abdominal and Thoracic Malignancies

Magnetic resonance-guided radiation therapy (MRgRT) offers advantages for image guidance for radiotherapy treatments as compared to conventional computed tomography (CT)-based modalities. The superior soft tissue contrast of magnetic resonance (MR) enables an improved visualization of the gross tumor and adjacent normal tissues in the treatment of abdominal and thoracic malignancies. Online adaptive capabilities, coupled with advanced motion management of real-time tracking of the tumor, directly allow for high-precision inter-/intrafraction localization. The primary aim of this case series is to describe MR-based interventions for localizing targets not well-visualized with conventional image-guided technologies. The abdominal and thoracic sites of the lung, kidney, liver, and gastric targets are described to illustrate the technological advancement of MR-guidance in radiotherapy.

Impact of HPV Status on the Prognostic Potential of the AJCC Staging System for Larynx Cancer

Objective We evaluated the ability of the American Joint Committee on Cancer (AJCC) seventh edition staging system to prognosticate the overall survival of patients with human papillomavirus (HPV)-positive laryngeal squamous cell carcinoma. Study Design Retrospective analysis. Setting National Cancer Database. Subjects and Methods Patients diagnosed with laryngeal squamous cell carcinoma who were treated with curative intent were identified in the National Cancer Database. Multivariate analysis was utilized to determine factors correlated with overall survival in the HPV-negative and HPV-positive cohorts. Unadjusted and propensity score-weighted Kaplan-Meier estimation was used to determine overall survival of HPV-negative and HPV-positive patients across AJCC stage groupings. Results We identified 3238 patients with laryngeal squamous cell carcinoma, of which 2812 were HPV negative and 426 were HPV positive. Overall survival adjusted for age, sex, and comorbidity status confirmed significant differences among all consecutive stage groupings (I vs II, P < .001; II vs III, P < .05; III vs IVA, P < .001; IVA vs IVB, P < .05) in the HPV-negative cohort, whereas only stages IVAs and IVB ( P < .01) exhibited a significant difference in overall survival for HPV-positive patients. Conclusion The current AJCC staging system does not accurately distinguish risk of mortality for patients with HPV-positive disease. These data support the consideration of HPV status in estimating prognosis as well as clinical trial design and clinical decision making for patients with laryngeal squamous cell carcinoma.

HPV impacts survival of stage IVC non-oropharyngeal HNSCC cancer patients

Objectives

Human papillomavirus (HPV) status is a favorable prognostic marker for patients with oropharyngeal squamous cell carcinoma (OPSCC) and non-metastatic head and neck non-OPSCC. We evaluated the impact of HPV status on overall survival (OS) for patients with Stage IVC non-OPSCC.

Materials and methods

Patients diagnosed with Stage IVC non-OPSCC and known HPV status between 2010-2013 were identified in the National Cancer Database. Univariate and multivariate analyses were performed to determine factors associated with OS. Propensity score-weighted Kaplan-Meier estimation was used to adjust for confounders in OS analyses. Multiple imputation method was used for sensitivity analysis.

Results

We identified 708 patients with Stage IVC non-OPSCC with 30% being HPV-positive. Unadjusted median survival was 10.3 months for HPV-negative patients and 21.4 months for HPV-positive patients (p<0.0001). Age ≥ 65 and tumor diameter were associated with worse OS (p<0.05) while treatment versus no treatment and HPV-positive status were associated with improved OS on multivariate analysis (p<0.001). Adjusted median survival for patients with HPV-negative and HPV-positive disease was 11.1 months and 23.8 months, respectively (p<0.001). On unadjusted subgroup analysis, patients with HPV-positive oral cavity disease exhibited improved outcomes (p<0.0001) while HPV-positive hypopharynx (p<0.06) and larynx (p<0.12) patients exhibited a trend for improved OS compared to HPV-negative patients. The survival advantage associated with HPV positivity was maintained on sensitivity analysis (p<0.01).

Conclusion

These data demonstrate a clinically meaningful association between HPV status and OS in patients with non-OSPCC presenting with Stage IVC disease. In the absence of randomized data, these findings support active consideration of HPV status in clinical decision making, clinical trial design, and patient counseling regarding prognosis.

Survival Outcomes for Patients With T3N0M0 Squamous Cell Carcinoma of the Glottic Larynx

Importance

Radiotherapy (RT)-based organ preservation approaches for patients with advanced laryngeal cancer have been established stepwise through prospective randomized clinical trials. However, broad adoption of these approaches has stimulated discussion about long-term results challenging their applicability in a heterogeneous patient population, most recently for patients with T3 disease.

Objective

To define outcomes in patients with clinical T3N0M0 glottic laryngeal cancer treated with definitive surgical and RT-based approaches.

Design, Setting, and Participants

This retrospective cohort study included patients treated from January 1, 2004, through December 31, 2013, with a median follow-up time of 58 months (range, 0-126.6 months) in the National Cancer Database. Of the 4003 patients with T3N0M0 disease, 2622 received definitive therapy defined by the study protocol. Data were obtained from the clinical oncology database sourced from hospital registry data that are collected from more than 1500 Commission on Cancer-accredited facilities. Data were analyzed from September 14, 2016, through April 24, 2017.

Interventions

Radiotherapy, chemoradiotherapy, surgery, surgery and RT, or surgery and chemoradiotherapy.

Main Outcomes and Measures

Five-year overall survival (OS).

Results

A total of 2622 patients (2251 men [85.9%] and 371 women [14.1%]; median age, 64 years [range, 19-90 years]) were included in the analytic cohort. In the overall patient cohort, the adjusted 5-year survival probability was 53%. No statistical differences were observed between the primary surgery (53%; 95% CI, 48%-57%) and primary RT (54%; 95% CI, 52%-57%) cohorts. In multivariate analysis, patient factors associated with decreased OS included age (hazard ratio [HR], 1.04; 95% CI, 1.03-1.04), insurance status (HR, 1.26; 95% CI, 1.06-1.50), and increasing comorbidity (HR, 1.20; 95% CI, 1.02-1.42).

Conclusions and Relevance

Current management of T3N0M0 glottic laryngeal cancer relies largely on RT-based organ preservation approaches. The present study substantiates randomized clinical trial data supporting the use of RT-based organ preservation approaches for patients with T3N0M0 glottic laryngeal cancer without compromising OS.

Prognostic implications of human papillomavirus status for patients with non-oropharyngeal head and neck squamous cell carcinomas

PURPOSE

We examined overall survival in a large cohort of patients with human papillomavirus (HPV)-positive and HPV-negative non-oropharyngeal squamous cell carcinoma of the head and neck (non-OPSCC).

METHODS

Patients diagnosed with non-OPSCC and known HPV status were identified in the National Cancer Database (NCDB). Multivariate logistic regression was applied to examine factors associated with HPV status. Multivariate analysis was utilized to determine factors correlated with overall survival. Propensity score-weighted Kaplan-Meier estimation was used to adjust for confounders in survival analyses. Multiple imputation method was used for sensitivity analysis.

RESULTS

We identified 19,993 non-OPSCC patients with 5070 being positive for HPV in the NCDB. Median follow-up was 23.5 months. HPV-positive patients were more commonly male, white, with a lower comorbidity index score, presenting with T-stage <2, and N-stage ≥1. Unadjusted 3-year overall survival was 62% and 80% for HPV-negative and HPV-positive patients, respectively (p < 0.0001). On multivariate analysis, mortality was reduced for HPV-positive patients with early stage (HR = 0.68) and locally advanced disease (HR = 0.46). Adjusted 3-year overall survival was 65% for HPV-negative and 76% for HPV-positive patients (p < 0.0001). The survival advantage of HPV was maintained in all subsites and robust on sensitivity analysis.

CONCLUSIONS

Patients with HPV-positive non-OPSCC exhibit similar characteristics as HPV-positive OPSCC. Overall survival was significantly higher for patients with HPV-positive versus HPV-negative non-OPSCC. These data reveal that HPV-positive non-OPSCC represent a favorable cohort that warrants recognition in the design of future clinical trial investigation.

Clinical outcomes for patients presenting with N3 head and neck squamous cell carcinoma: Analysis of the National Cancer Database

BACKGROUND

There is a paucity of data regarding head and neck squamous cell carcinomas (HNSCCs) and N3 nodal disease.

METHODS

Retrospective analysis of patients with N3 HNSCC identified in the National Cancer Database (NCDB) was performed.

RESULTS

We identified 4867 patients with N3 HNSCC treated with primary surgery or chemoradiotherapy (CRT). Propensity-adjusted median survival was 54.2 and 44.8 months for surgery and CRT, respectively (P = .06). Oropharyngeal primary subsite demonstrated a survival advantage with surgery versus CRT with propensity-adjusted median survivals of 86.0 and 61.9 months, respectively (P < .05).

CONCLUSION

Management of N3 HNSCC relies largely on CRT. Patients with N3 nodal disease with nonoropharyngeal primary tumors exhibit 5-year overall survival approaching 30% independent of initial treatment modality. Patients with oropharyngeal primaries exhibit improved outcomes with surgery largely influenced by the human papillomavirus (HPV)-negative subset. These data represent the most comprehensive analysis of N3 HNSCC outcomes and serves as a foundation for future research and clinical management.

Abstract 4121: Androgen receptor as a potential target in non-small cell lung cancer

The cancer genome atlas (TCGA) has identified androgen receptor (AR) to be mutated, deleted and amplified across human lung squamous cell carcinoma and adenocarcinoma. Expression of AR is critical for early lung development. However, the intriguing expression of AR in non-small cell lung cancer (NSCLC) opens up an alternative treatment paradigm in the event of onset of clinical resistance to lung cancer drugs. To investigate this potential, a) 10 NSCLC cell lines and 3 control prostate cancer cell lines were stimulated with synthetic AR agonist, R1881 at 24, 48 and 72 hours. 0.5-4-fold RNA and protein expression was found across these lung cancer cell lines when compared to unstimulated cells. b) droplet digital PCR revealed varying copies of AR DNA when benchmarked to prostate AR. c) cell proliferation assays of these cell lines with enzalutamide (MVD3100) treatment resulted in 50-65% cell survival at concentrations ranging from 10 - 25 µM. d) Immunohistochemical staining of AR in a NSCLC human tissue microarray (TMA) revealed 10 out of 88 patients (11%) to have AR positive staining in their tumor. This included 6 adenocarcinomas and 2 squamous cell carcinomas. 8 patients had focal while 2 had diffuse staining. Validation of the TMA performed with whole mount slides confirmed diffuse staining in these 11 samples. Taken together, these findings suggest AR is a potential therapeutic target in NSCLC and further work is underway to test these observations in drug resistant lung cancer cell lines and pre-clinical mouse models.

Citation Format: Sean Brennan, Albert R. Wang, Hope Beyer, Dylan Wiese, Darya Buehler, Anwaar Saeed, Andrew M. Baschnagel, Gopal Iyer. Androgen receptor as a potential target in non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4121. doi:10.1158/1538-7445.AM2017-4121

Abstract 1094: Combining the pan-FGFR inhibitor AZD4547 with radiation in lung and head and neck squamous cell carcinoma

The fibroblast growth factor receptors (FGFR1, FGR2, FRG3, FGR4) are frequently altered or overexpressed in both lung and head and neck squamous cell carcinomas (SCC). Amplification of FGFR1 has been reported to be as high as 22% in lung SCC and 17% in head and neck SCC (HNSCC). FGFRs have been identified as a potential therapeutic target in lung and head and neck cancers. In addition, FGFRs activate multiple pathways involved in the radiation response including RAS/RAF/MAPK, PI3K/AKT and STAT. AZD4547 is a potent and selective tyrosine kinase inhibitor of the FGFR family and is currently being investigated in clinical trials. Since a substantial portion of lung cancer and HNSCC patients are treated with radiotherapy, we examined the anti-tumor effects of AZD4547 in combination with radiation in both lung and head and neck cancer model systems. FGFR protein and RNA expression and cell proliferation with AZD4547 were evaluated in 8 lung and 8 head and neck cancer cell lines. Clonogenic survival assays were performed on 4 lung and 4 head and neck cancer cell lines and xenograft experiments were performed on one HNSCC cell line. These cell lines demonstrated varying levels of FGFR1, 2 and 3 protein and RNA expression. The half maximal inhibitory concentration (IC50) of AZD4547 in these cell lines ranged from 0.05 to 128 uM. Sensitivity to AZD4547 did not correlate directly with protein or RNA expression. In vitro clonogenic survival assays showed limited effects of combining AZD4547 with radiation. However, significant tumor growth delay was observed with the combination of radiation and AZD4547 compared to radiation or drug alone in the SCC1483 FGFR2 expressing HNSCC xenograft model. These findings suggest that AZD4547 can augment the response of radiation in an in vivo model system. Further studies are underway to test these findings in additional cell lines including FGFR dependent amplified cancer cell lines.

Citation Format: Andrew M. Baschnagel, Chunrong Li, Alecia M. Morgan, Sean R. Brennan, Kalley A. Russo, Paul M. Harari. Combining the pan-FGFR inhibitor AZD4547 with radiation in lung and head and neck squamous cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1094. doi:10.1158/1538-7445.AM2017-1094

Small cell carcinoma of the head and neck: An analysis of the National Cancer Database

PURPOSE/OBJECTIVE(S)

To evaluate treatment trends and overall survival of patients with small cell carcinoma of the head and neck region.

MATERIALS/METHODS

Patients from 2004 to 2012 were identified from the National Cancer Database. Patient demographics and overall survival were analyzed. Multivariable analysis was used to identify predictors of survival.

RESULTS

Among 347,252 head and neck patients a total of 1042 (0.3%) patients with small cell carcinoma were identified. 17% of patients were diagnosed as stage I/II, 61% as stage III/IVA/IVB and 22% as stage IVC disease. The distribution by anatomic site was 9% oral cavity, 12% oropharynx, 35% larynx, 4% hypopharynx, 10% nasopharynx and 30% nasal cavity and paranasal sinuses. The median overall survival by anatomical site was 20.8months for oral cavity, 23.7months for oropharynx, 17.9months for larynx/hypopharynx, 15.1months for nasopharynx and 36.4months for nasal cavity primary tumors. On multivariable analysis across stage, patients with nasal cavity and paranasal sinuses tumors had the best survival and patients with nasopharynx primaries had the worst survival. In stage I/II patients, type of treatment delivered resulted in no overall survival difference (p=0.78). In patients with locally advanced disease, there was no difference in survival between those treated with combined surgery, radiotherapy and chemotherapy compared to those treated only with radiotherapy and chemotherapy (p=0.46). The addition of radiotherapy to chemotherapy in the metastatic setting did not result in improved survival (p=0.14).

CONCLUSIONS

Small cell carcinoma of the head and neck is a rare malignancy with a poor prognosis. The addition of surgery to radiotherapy and chemotherapy did not improve survival in patients with locally advanced disease.

The significance of Trk receptors in pancreatic cancer

This study investigated the Trk receptor family as a therapeutic target in pancreatic ductal adenocarcinoma and assessed their prognostic significance. Global gene expression analysis was investigated in prospectively collected pancreatic ductal adenocarcinomas that had either undergone neoadjuvant chemoradiation or were treated by surgery. PANC-1 and MIA-PaCa-2 cell lines were investigated to establish whether fractionated radiation altered expression of four neuroendocrine genes and whether this resulted in subsequent changes in radiosensitivity. A specific inhibitor of TrkA, B, and C, AstraZeneca 1332, was investigated in vitro and in vivo in combination with radiation. A tissue microarray was constructed from 77 pancreatic ductal adenocarcinoma patients who had undergone neoadjuvant chemoradiation and the Trk receptor, and neurogenic differentiation 1 expression was assessed and correlated with overall survival. A total of 99 genes were identified that were differentially expressed in the chemoradiation patients with neuroendocrine genes and pathways, in particular the neurogenic differentiation 1 and Trk receptor family, being prominent. Fractionated radiation upregulated the expression of neuroendocrine genes, and AstraZeneca 1332 treatment in vitro enhanced radiosensitivity. No added effect of AstraZeneca 1332 was observed in vivo. Trk receptor expression varied between isoforms but did not correlate significantly with clinical outcome. Radiation treatment upregulated neuroendocrine gene expression but the Trk receptor family does not appear to be a promising treatment target.

Strategies for Translating Evidence-Based Medicine in Lung Cancer into Community Practice

The landscape of non-small cell lung cancer (NSCLC) treatment has rapidly evolved over the past decade. This is exemplified by the use of molecular targeted agents, immunotherapies, and newer technologies such as stereotactic body radiotherapy (SBRT). As the translation of preclinical discoveries into clinical practice continues, the effective dissemination and implementation of evidence-based treatment of NSCLC will remain a foremost challenge for oncologists. To further extend evidence-based medicine into the community setting, community oncologists are being engaged on multiple fronts including leadership and participation in national clinical trials and utilization of internet-based resources.

Dosimetric Comparison of Real-Time MRI-Guided Tri-Cobalt-60 Versus Linear Accelerator-Based Stereotactic Body Radiation Therapy Lung Cancer Plans

Purpose:

Magnetic resonance imaging–guided radiation therapy has entered clinical practice at several major treatment centers. Treatment of early-stage non-small cell lung cancer with stereotactic body radiation therapy is one potential application of this modality, as some form of respiratory motion management is important to address. We hypothesize that magnetic resonance imaging–guided tri-cobalt-60 radiation therapy can be used to generate clinically acceptable stereotactic body radiation therapy treatment plans. Here, we report on a dosimetric comparison between magnetic resonance imaging–guided radiation therapy plans and internal target volume–based plans utilizing volumetric-modulated arc therapy.

Materials and Methods:

Ten patients with early-stage non-small cell lung cancer who underwent radiation therapy planning and treatment were studied. Following 4-dimensional computed tomography, patient images were used to generate clinically deliverable plans. For volumetric-modulated arc therapy plans, the planning tumor volume was defined as an internal target volume + 0.5 cm. For magnetic resonance imaging–guided plans, a single mid-inspiratory cycle was used to define a gross tumor volume, then expanded 0.3 cm to the planning tumor volume. Treatment plan parameters were compared.

Results:

Planning tumor volumes trended larger for volumetric-modulated arc therapy–based plans, with a mean planning tumor volume of 47.4 mL versus 24.8 mL for magnetic resonance imaging–guided plans (P = .08). Clinically acceptable plans were achievable via both methods, with bilateral lung V20, 3.9% versus 4.8% (P = .62). The volume of chest wall receiving greater than 30 Gy was also similar, 22.1 versus 19.8 mL (P = .78), as were all other parameters commonly used for lung stereotactic body radiation therapy. The ratio of the 50% isodose volume to planning tumor volume was lower in volumetric-modulated arc therapy plans, 4.19 versus 10.0 (P < .001). Heterogeneity index was comparable between plans, 1.25 versus 1.25 (P = .98).

Conclusion:

Magnetic resonance imaging–guided tri-cobalt-60 radiation therapy is capable of delivering lung high-quality stereotactic body radiation therapy plans that are clinically acceptable as compared to volumetric-modulated arc therapy–based plans. Real-time magnetic resonance imaging provides the unique capacity to directly observe tumor motion during treatment for purposes of motion management.

Radiation Dose Escalation in Esophageal Cancer Revisited: A Contemporary Analysis of the National Cancer Data Base, 2004 to 2012

PURPOSE

To evaluate the effect of radiation dose escalation on overall survival (OS) for patients with nonmetastatic esophageal cancer treated with concurrent radiation and chemotherapy.

METHODS AND MATERIALS

Patients diagnosed with stage I to III esophageal cancer treated from 2004 to 2012 were identified from the National Cancer Data Base. Patients who received concurrent radiation and chemotherapy with radiation doses of ≥50 Gy and did not undergo surgery were included. OS was compared using Cox proportional hazards regression and propensity score matching.

RESULTS

A total of 6854 patients were included; 3821 (55.7%) received 50 to 50.4 Gy and 3033 (44.3%) received doses >50.4 Gy. Univariate analysis revealed no significant difference in OS between patients receiving 50 to 50.4 Gy and those receiving >50.4 Gy (P=.53). The dose analysis, binned as 50 to 50.4, 51 to 54, 55 to 60, and >60 Gy, revealed no appreciable difference in OS within any group compared with 50 to 50.4 Gy. Subgroup analyses investigating the effect of dose escalation by histologic type and in the setting of intensity modulated radiation therapy also failed to reveal a benefit. Propensity score matching confirmed the absence of a statistically significant difference in OS among the dose levels. The factors associated with improved OS on multivariable analysis included female sex, lower Charlson-Deyo comorbidity score, private insurance, cervical/upper esophagus location, squamous cell histologic type, lower T stage, and node-negative status (P<.01 for all analyses).

CONCLUSIONS

In this large national cohort, dose escalation >50.4 Gy did not result in improved OS among patients with stage I to III esophageal cancer treated with definitive concurrent radiation and chemotherapy. These data suggest that despite advanced contemporary treatment techniques, OS for patients with esophageal cancer remains unaltered by escalation of radiation dose >50.4 Gy, consistent with the results of the INT-0123 trial. Furthermore, these data highlight that many radiation oncologists have not embraced the concept that dose escalation does not improve OS. Although local control, not investigated in the present study, might benefit from dose escalation, novel therapies are needed to improve the OS of patients with esophageal cancer.

Improved survival with dose-escalated radiotherapy in stage III non-small-cell lung cancer: analysis of the National Cancer Database

BACKGROUND

Concurrent chemoradiation is the standard of care in non-operable stage III non-small-cell lung cancer (NSCLC). Data have suggested a benefit of dose escalation; however, results from the randomized dose-escalation trial RTOG 0617 revealed a lower survival rate with high-dose radiation. To evaluate the impact of dose escalation on overall survival (OS) in stage III NSCLC treated with chemoradiotherapy outside the controlled setting of a randomized trial, we carried out an observational, population-based investigation of the National Cancer Database (NCDB).

PATIENTS AND METHODS

A total of 33 566 patients with stage III NSCLC treated with chemoradiation from 2004 to 2012 and radiation doses between 59.4 and 85 Gy were included. The primary end point was OS, with median survival calculated via Kaplan-Meier. Univariate, multivariable and propensity-score matching analyses were carried out.

RESULTS

Patients were stratified by dose with median OS of: 18.8, 19.8 and 21.6 months for cohorts receiving 59.4-60, 61-69 and ≥70 Gy, respectively (P < 0.001). Granular dose analyses were carried out demonstrating increased OS with increasing radiation dose: median survival of 18.8, 21.1, 22.0 and 21.0 months for 59.4-60, 66, 70 and ≥71 Gy, respectively. While 66, 70 and ≥71 Gy resulted in increased OS in comparison with 59.4-60 Gy, no significant difference in OS was observed when comparing 66 with ≥71 Gy (P = 0.38).

CONCLUSIONS

Dose escalation above 60 Gy was associated with improved OS in this cohort of stage III NSCLC patients treated with chemoradiotherapy. A plateau of benefit was observed, with no additional improvement in OS with increased dose (≥71 Gy) compared with 66-70 Gy. With evidence suggesting worse OS and quality of life with increased dose, these data support investigation of the role of intermediate-dose radiation, and in the absence of randomized evidence, may be leveraged to justify utilization of intermediate-dose radiation.

Combined CD44, c-MET, and EGFR expression in p16-positive and p16-negative head and neck squamous cell carcinomas

PURPOSE/OBJECTIVE(S)

To examine the association between CD44 and c-MET expression in relation to p16 and EGFR in patients with head and neck squamous cell carcinoma (HNSCC).

MATERIALS/METHODS

Immunohistochemical staining of CD44, p16, EGFR, and c-MET was performed on 105 locally advanced HNSCC patients treated with chemoradiation. CD44 expression was correlated with c-MET, EGFR, and p16, locoregional control (LRC), distant metastases (DM), disease-free survival (DFS) and overall survival (OS).

RESULTS

High CD44 expression was present in 33% of patients and was associated with non-oropharynx primaries (P < 0.001), high c-MET expression (P < 0.001), p16-negative (P < 0.001) and EGFR-positive tumors (P < 0.001). Fifty-seven percent of CD44 high expressing tumors had high c-MET expression compared to 21% of CD44 low expressing tumors (P < 0.001). High CD44 expression predicted for worse LRC (HR: 2.44; 95% CI: 1.16-5.13; P = 0.018), DFS (HR: 2.61; 95% CI: 1.46-4.67; P = 0.001), and OS (HR: 2.52; 95% CI: 1.30-4.92; P = 0.007) but not DM (P = 0.57) on univariate analysis. Patients with both high CD44 and c-MET expression had a poor prognosis with a 2-year DFS of 30% compared to 70% in the rest of the cohort (P = 0.003). On multivariable analysis, after adjusting for site, T-stage, smoking history, and EGFR status, high c-MET (P = 0.039) and negative p16 status (P = 0.034) predicted for worse DFS, while high CD44 expression did not (P = 0.43).

CONCLUSIONS

High CD44 expression is associated with high c-MET expression, p16-negative tumors, and EGFR-positive tumors. The combination of these markers predicts for poor prognosis in HNSCC patients treated with chemoradiation.

Crizotinib Fails to Enhance the Effect of Radiation in Head and Neck Squamous Cell Carcinoma Xenografts

AIM

Mesenchymal-epithelial transition factor (MET), a receptor tyrosine kinase, is expressed in head and neck squamous cell carcinomas (HNSCC) and is involved in tumor progression and associated with poor prognosis. MET can be inhibited by crizotinib, a potent ATP-competitive kinase inhibitor. We examined the effects of combining crizotinib and radiation in a pre-clinical HNSCC model.

MATERIALS AND METHODS

Nine HNSCC cell lines were screened for MET expression, copy-number amplification and mutational status. The in vitro effects of crizotinib and radiation were assessed with clonogenic survival assays. MET signaling proteins were assessed with western blot and receptor tyrosine kinase array. Tumor growth-delay experiments with UT-SCC-14 and UT-SCC-15 oral tongue xenografts were used to assess in vivo tumor radiosensitivity.

RESULTS

All nine HNSCC cell lines showed a varying degree of MET protein and RNA expression. Increased MET copy number was not present. MET was expressed after irradiation both in vitro and in vivo. Crizotinib alone inhibited phosphorylation of MET and inhibited cell growth in vitro but did not inhibit phosphorylation of downstream signaling proteins: MAPK, AKT or c-SRC. When combined with radiation in vitro, crizotinib demonstrated radiation enhancement in only one cell line. Crizotinib did not enhance the effect of radiation in either UT-SCC-14 or UT-SCC-15 tumors grown as xenografts.

CONCLUSION

MET is overexpressed in HNSCC cell lines, however, crizotinib failed to enhance the radiation response and failed to inhibit MET downstream signaling proteins in this HNSCC model.