Comparing effectiveness of image perturbation and test retest imaging in improving radiomic model reliability

Image perturbation is a promising technique to assess radiomic feature repeatability, but whether it can achieve the same effect as test-retest imaging on model reliability is unknown. This study aimed to compare radiomic model reliability based on repeatable features determined by the two methods using four different classifiers. A 191-patient public breast cancer dataset with 71 test-retest scans was used with pre-determined 117 training and 74 testing samples. We collected apparent diffusion coefficient images and manual tumor segmentations for radiomic feature extraction. Random translations, rotations, and contour randomizations were performed on the training images, and intra-class correlation coefficient (ICC) was used to filter high repeatable features. We evaluated model reliability in both internal generalizability and robustness, which were quantified by training and testing AUC and prediction ICC. Higher testing performance was found at higher feature ICC thresholds, but it dropped significantly at ICC = 0.95 for the test-retest model. Similar optimal reliability can be achieved with testing AUC = 0.7-0.8 and prediction ICC > 0.9 at the ICC threshold of 0.9. It is recommended to include feature repeatability analysis using image perturbation in any radiomic study when test-retest is not feasible, but care should be taken when deciding the optimal feature repeatability criteria.

Radiation-Induced Brachial Plexopathy (RIBP) after Stereotactic Body Radiotherapy (SBRT): Pooled Analyses of Risks

PURPOSE/OBJECTIVE(S)

RIBP, with symptomatic upper extremity motor or sensory deficits, is a risk after SBRT. We herein model dosimetric factors associated with risks of RIBP of the inferior aspect of the brachial plexus following SBRT for apical lung tumors.

MATERIALS/METHODS

Literature searches (PubMed & Embase databases) were performed to identify reports published from 2000-2021, using search criteria of ["brachial plex*" and stereotactic]. From a PRISMA systematic review, studies were identified that included individual patient data on: (1) RIBP endpoints after SBRT for apical lung tumors; and (2) brachial plexus Dmax, or maximum point doses (i.e., D0.035cc or D0.03cc). These data were amenable to normal tissue complication probability (NTCP) modelling. Doses were converted using the linear-quadratic model with an alpha-beta ratio of 3 Gy. For the probit models, the parameter values were determined using the maximum likelihood method and the 95% confidence intervals (CI) were determined using the profile likelihood method. The ability of the NTCP models to distinguish patients with and without RIBP was evaluated using the area under the curve (AUC).

RESULTS

Two probit NTCP models were derived: one from 3 studies (185 patients with 192 targets and 11 events) and another from 4 studies (221 patients with 229 targets and 18 events). NTCP models (summarized in table) suggest ≈10% risks associated with brachial plexus maximum dose (Dmax) of ∼32-34 Gy in 3 fractions and ∼40-43 Gy in 5 fractions, with a clear dose response. These dose-responses with SBRT (with steep dose gradients beyond the target volume and thus only partial-irradiation of the brachial plexus) are far less steep than those reported following conventionally-fractionated or moderately-hypofractionated radiotherapy used for breast, lung and head and neck cancers (that tend to use radiotherapy fields that circumferentially irradiate the brachial plexus).

CONCLUSION

A dose-response for risk of RIBP after SBRT is observed relative to brachial plexus Dmax. The less-steep dose-response compared to that seen from conventionally-fractionated or moderately-hypofractionated radiotherapy (with large irradiated plexus volumes) suggest a possible volume dependence of RIBP risks. Future work should focus on understanding possible volume effects.

Interpretable Deep Learning Identified the Significance of 1 Gy Volume on Lymphopenia after Radiotherapy in Breast Cancer

PURPOSE/OBJECTIVE(S)

Lymphopenia is common after radiotherapy (RT) and is known for its significance on poor survival outcomes in patients with breast cancer. Previous work has demonstrated the significance of point dosimetric factors like the volume receiving 5 Gy. Considering the full dosimetric data together, this study aimed to develop and validate predictive models for lymphopenia after RT in breast cancer.

MATERIALS/METHODS

Patients with breast cancer treated with radiation therapy in adjuvant setting and with complete dosimetric data were eligible. Combining dose-volume histogram (DVH) dosimetric and clinical factors, dense neural network (DNN) models were developed to predict both the reduction in lymphocyte counts and the graded lymphopenia in breast cancer patients after adjuvant RT. A Shapley additive explanation was applied to explain each feature's directional contributions. The generalization of DNN models was validated in both internal and independent external validation cohorts. P<0.05 was considered to be significant.

RESULTS

A total of 928 consecutive patients with invasive breast cancer were eligible for this study. Treatment volumes of nearly all irradiation dose levels of DVH were significant predictors for lymphopenia after RT, including volumes at very low-dose 1 Gy (V1) of all structures considered including the lung, heart and body. DNN models using full DVH dosimetric and clinical factors were built and a simplified model was further established and validated in both internal and external validation cohorts. This simplified DNN AI model, combining full DVH dosimetric parameters of all OARs and five key clinical factors including baseline lymphocyte counts, tumor stage, RT technique, RT fields and RT fractionation, showed a predictive accuracy of 77% and above.

CONCLUSION

This study demonstrated and externally validated the significance of an AI model of combining clinical and full dosimetric data, especially the volume of low dose at as low as 1 Gy of all critical structures on lymphopenia after RT in patients with breast cancer. The significance of V1 deserves special attention, as modern arc RT technology often has relatively high value of this parameter. Further study warranted for breast cancer RT plan optimization.

Exploration of AI-Assisted On-Board Perfusion Imaging Technique on Patients Undergoing Thoraxradiotherapy

PURPOSE/OBJECTIVE(S)

Pulmonary function of lung cancer patients can significantly change along the radiation therapy (RT) course. Scholars have synthesized lung function maps from computed tomography (CT) images. Still, there is lack of study exploring the feasibility of generating lung perfusion information from cone-beam CT (CBCT). Our study aims to fill up this gap in the body of literatures.

MATERIALS/METHODS

One-hundred-and-six pairs of planning CT and CBCT images of thoracic cancer patients from XX hospital were collected retrospectively. All CT images were registered to CBCT with a deformable algorithm, and referred as deformed planning CT (dCT). A 2D convolutional neural network (CNN) model built with cycle generative adversarial network (cycle-GAN) was trained to correct CBCT image artifacts and HU value discrepancies. The corrected CBCT was named enhanced CBCT (eCBCT) in this study. All CBCT, eCBCT and dCT images were then input to a pre-trained CT-to-perfusion deep learning (DL) model to synthesize perfusion images (PI), namely PICBCT, PIeCBCT and PIdCT respectively. For model training, 80 image pairs were assigned to the training set while others to the testing set. dCT and PIdCT were respectively regarded as the ground truth in two consecutive models. One extra validation case acquired with SPECT perfusion scan was collected for model performance test. Quantitative evaluation was done between the ground truth and the synthesized images. Peak signal-to-noise ratio (PSNR) and mean absolute error (MAE) were computed to assess efficacy of CBCT enhancement. Correlation (R) and Dice similarity coefficient (DSC) were used to evaluate voxel-wise and function-wise concurrence in CBCT-derived perfusion mapping.

RESULTS

In CBCT enhancement, [eCBCT-dCT] pairs demonstrated higher agreement than [CBCT-dCT] pairs. Quantitatively, PSNR and MAE were improved from 21.10±1.60 to 24.08±1.76, and 68.99±13.51 to 47.06±11.31 (p<0.01), respectively. For perfusion translation, higher correlation was demonstrated in both voxel-wise and function-wise evaluation within [PIeCBCT-PIdCT] than [PICBCT-PIdCT]. R correlation increased from 0.84±0.09 to 0.89±0.06 (p<0.01), whereas DSC in high-functional regions increased from 0.77±0.06 to 0.82±0.05 (p<0.01). In the validation case, strong correlation was observed between SPECT perfusion scan and PIeCBCT, with R increasing from 0.57 to 0.65 when compared to PICBCT.

CONCLUSION

We proposed a novel DL framework that synthesized perfusion images from fractionally acquired CBCT. Our framework met the clinical needs in providing real-time lung perfusion maps. It can be used to track the continuously changing pulmonary function status throughout the RT course using routinely scanned CBCT, without additional imaging modalities. The framework can facilitate functionally guided adaptive radiation therapy by providing immediate pulmonary function information.

Single-Cell and Spatial Transcriptomics Revealing the Role of IDO1 in HPV+ Cervical Cancer Tumor Immune Microenvironment and Its Implications in Radiotherapy and Immunotherapy

PURPOSE/OBJECTIVE(S)

Persistent infection of human papillomavirus (HPV) is one major etiology of cervical cancer (CC). By now, anti-PD-1 immunotherapy is approved for advanced CC patients, but the response rate was just about 10-20%, tumor immune microenvironment (TIME) might be one factor that affect the efficacy. The indoleamine 2,3-dioxygenase (IDO), a metabolic immune checkpoint, is recently shown to have a correlation-ship with HPV carcinogenesis in CC, with unknown mechanism. This study, using the single cell transcriptomic single-cell sequencing and spatial transcription sequencing analysis/immunologic technology, aimed to exam the role of IDO1 expression in HPV+ CC TIME and explore the changes after radiotherapy.

MATERIALS/METHODS

Newly diagnosed advanced HPV- CC and HPV+ CC patients were tested for the tumor and tumor immune microenvironment (TIME) heterogeneity and their changes after fractionated radiation therapy. Tumor tissues were collected, single cell suspension was made for Single-cell RNA sequencing (SCRNAseq) using the 10 × Genomics, while frozen tissue was embedded for spatial transcriptome sequencing (STRNAseq). Seurat 4.0 was used to cluster and annotate cell clusters and map SCRNAseq data to the STRNAseq data. The specific characters of cell clusters were computed by Gene Set Enrichment Analysis (GSEA). SPOTLight and CellChat were used to analyze cell location and interaction respectively.

RESULTS

A total of 28631 cells were clustered into 31 cell subsets in HPV- CC and HPV+ CC tissues, including baseline (Pre HPV- CC and Pre HPV+ CC) and 3-week after radiotherapy (Post 3w HPV- CC and Post 3w HPV+CC). There were 10431 epithelial cells (Epi) in all these 4 tumor tissues, with heterogenous IDO1 expression, including IDO1-high Epi, IDO1-low Epi, and IDO1-neg Epi. Interestingly, more than 99% of Epi in Pre HPV- CC tissues were IDO1-neg cells, while more than 99% in Pre HPV+ CC tissue were IDO1-high. Furthermore, the proportion of IDO1-high Epi in Pre HPV+ CC patient dropped to 16.7% after radiotherapy, while the proportion of IDO1-low Epi rase to 63.3%. Using GSEA, the characters of IDO1-high Epi group was shown to have positive regulation of leukocyte chemotaxis and negative regulation of cell adhesion and differentiation. IDO1-high Epi cells also had the hallmark of interferon gamma response. These cells could mainly receive regulative information of interferon gamma pathway from exhausted CD8 T cells, which could affect the apoptosis of tumor cells.

CONCLUSION

This study comprehensively analyzed the immune suppressive role of IDO1-high Epi cells in HPV+ CC TIME at the single-cell transcriptional scale and explored their functional characters in CC radiotherapy. This would be able to provide more evidence to combine with radiotherapy and immunotherapy to improve patients' prognosis.

Regorafenib induces NOX5-mediated endoplasmic reticulum stress and potentiates the anti-tumor activity of cisplatin in non-small cell lung cancer cells

Lung cancer is one of the most commonly diagnosed cancers worldwide. Although cisplatin-based chemotherapy regimens serve a pivotal role in non-small cell lung cancer (NSCLC) treatment, drug resistance and serious side effects limited its further clinical application. Regorafenib, a small-molecule multi-kinase inhibitor, was demonstrated to have promising anti-tumor activity in various solid tumors. In the present study, we found that regorafenib markedly enhanced cisplatin-induced cytotoxicity in lung cancer cells by activating reactive oxygen species (ROS)-mediated endoplasmic reticulum stress (ER Stress), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) signaling pathways. Regorafenib increased ROS generation by promoting NADPH oxidase 5 (NOX5) expression, and knocking down NOX5 attenuated ROS-mediated cytotoxicity of regorafenib in lung cancer cells. Additionally, mice xenograft model validated that synergistic anti-tumor effects of combined treatment with regorafenib and cisplatin. Our results suggested that combination therapy with regorafenib and cisplatin may serve as a potential therapeutic strategy for some NSCLC patients.

A super-voxel-based method for generating surrogate lung ventilation images from CT

Purpose: This study aimed to develop and evaluate CTVISVD , a super-voxel-based method for surrogate computed tomography ventilation imaging (CTVI). Methods and Materials: The study used four-dimensional CT (4DCT) and single-photon emission computed tomography (SPECT) images and corresponding lung masks from 21 patients with lung cancer obtained from the Ventilation And Medical Pulmonary Image Registration Evaluation dataset. The lung volume of the exhale CT for each patient was segmented into hundreds of super-voxels using the Simple Linear Iterative Clustering (SLIC) method. These super-voxel segments were applied to the CT and SPECT images to calculate the mean density values (D _mean) and mean ventilation values (Vent _mean), respectively. The final CT-derived ventilation images were generated by interpolation from the D _mean values to yield CTVISVD. For the performance evaluation, the voxel- and region-wise differences between CTVISVD and SPECT were compared using Spearman's correlation and the Dice similarity coefficient index. Additionally, images were generated using two deformable image registration (DIR)-based methods, CTVIHU and CTVIJac, and compared with the SPECT images. Results: The correlation between the D _mean and Vent _mean of the super-voxel was 0.59 ± 0.09, representing a moderate-to-high correlation at the super-voxel level. In the voxel-wise evaluation, the CTVISVD method achieved a stronger average correlation (0.62 ± 0.10) with SPECT, which was significantly better than the correlations achieved with the CTVIHU (0.33 ± 0.14, p < 0.05) and CTVIJac (0.23 ± 0.11, p < 0.05) methods. For the region-wise evaluation, the Dice similarity coefficient of the high functional region for CTVISVD (0.63 ± 0.07) was significantly higher than the corresponding values for the CTVIHU (0.43 ± 0.08, p < 0.05) and CTVIJac (0.42 ± 0.05, p < 0.05) methods. Conclusion: The strong correlation between CTVISVD and SPECT demonstrates the potential usefulness of this novel method of ventilation estimation for surrogate ventilation imaging.

Neoadjuvant Chemoradiotherapy and Surgery for Esophageal Squamous Cell Carcinoma Versus Definitive Chemoradiotherapy With Salvage Surgery as Needed: The Study Protocol for the Randomized Controlled NEEDS Trial

Background

The globally dominant treatment with curative intent for locally advanced esophageal squamous cell carcinoma (ESCC) is neoadjuvant chemoradiotherapy (nCRT) with subsequent esophagectomy. This multimodal treatment leads to around 60% overall 5-year survival, yet with impaired post-surgical quality of life. Observational studies indicate that curatively intended chemoradiotherapy, so-called definitive chemoradiotherapy (dCRT) followed by surveillance of the primary tumor site and regional lymph node stations and surgery only when needed to ensure local tumor control, may lead to similar survival as nCRT with surgery, but with considerably less impairment of quality of life. This trial aims to demonstrate that dCRT, with selectively performed salvage esophagectomy only when needed to achieve locoregional tumor control, is non-inferior regarding overall survival, and superior regarding health-related quality of life (HRQOL), compared to nCRT followed by mandatory surgery, in patients with operable, locally advanced ESCC.

Methods

This is a pragmatic open-label, randomized controlled phase III, multicenter trial with non-inferiority design with regard to the primary endpoint overall survival and a superiority hypothesis for the experimental intervention dCRT with regard to the main secondary endpoint global HRQOL one year after randomization. The control intervention is nCRT followed by preplanned surgery and the experimental intervention is dCRT followed by surveillance and salvage esophagectomy only when needed to secure local tumor control. A target sample size of 1200 randomized patients is planned in order to reach 462 events (deaths) during follow-up.

Clinical Trial Registration

www.ClinicalTrials.gov, identifier: NCT04460352.

Reshaping the systemic tumor immune environment (STIE) and tumor immune microenvironment (TIME) to enhance immunotherapy efficacy in solid tumors

The development of combination immunotherapy based on the mediation of regulatory mechanisms of the tumor immune microenvironment (TIME) is promising. However, a deep understanding of tumor immunology must involve the systemic tumor immune environment (STIE) which was merely illustrated previously. Here, we aim to review recent advances in single-cell transcriptomics and spatial transcriptomics for the studies of STIE, TIME, and their interactions, which may reveal heterogeneity in immunotherapy responses as well as the dynamic changes essential for the treatment effect. We review the evidence from preclinical and clinical studies related to TIME, STIE, and their significance on overall survival, through different immunomodulatory pathways, such as metabolic and neuro-immunological pathways. We also evaluate the significance of the STIE, TIME, and their interactions as well as changes after local radiotherapy and systemic immunotherapy or combined immunotherapy. We focus our review on the evidence of lung cancer, hepatocellular carcinoma, and nasopharyngeal carcinoma, aiming to reshape STIE and TIME to enhance immunotherapy efficacy.

Comparison of clinical outcome between stereotactic body radiotherapy and radiofrequency ablation for unresectable hepatocellular carcinoma

Stereotactic body radiotherapy (SBRT) is a novel noninvasive treatment for unresectable hepatocellular carcinoma (HCC). Whether its efficacy is comparable to radiofrequency ablation (RFA), a recommended therapy for unresectable HCC, is unknown. The present study aims to compare the clinical outcome between SBRT and RFA for patients with unresectable HCC.The clinical data of 60 patients with unresectable HCC from January 2018 to January 2021 were retrospectively reviewed. There were 22 cases treated by SBRT and 38 cases by RFA. The short-term and long-term clinical outcomes were compared.There was no significant difference in the baseline demographic characteristics between two groups. The complete remission rate at 3 months was comparable between SBRT group (81.8%) and RFA group (89.4%). Local tumor control rate was also similar between two groups (90.9% vs. 94.7%). There was no severe complication (grade IIIa or above) in both groups. The 1-year and 2-year overall survival rates were 88.2% and 85.7% in SBRT group and 100% and 75% in RFA group, respectively. There was no statistical significant difference between groups (P = .576).SBRT can achieve similar short and long-term clinical outcome as RFA for unresectable HCC. Future prospective clinical study is needed to justify its role in patients with HCC.

Effect of bladder volume on radiation doses to organs at risk and tumor in cervical cancer during image-guided adaptive brachytherapy and treatment outcome analysis

There is no consensus in clinical practice on the optimal bladder volume during brachytherapy. The present study aimed to assess the effect of bladder volume on radiation dose to organs at risk and tumor in cervical cancer during image-guided adaptive brachytherapy and clinical outcome. The retrospective study included patients treated at University of Hong Kong-Shenzhen Hospital between January 2015 and July 2019. Patients with International Federation of Gynecology and Obstetrics (2009) stage IB1-IVB (retroperitoneal lymph nodes metastasis only) cervical cancer treated by external beam radiotherapy with concurrent cisplatin followed by brachytherapy were assessed. A total of 421 brachytherapy insertions were analyzed. Every 83 and 90 cm³ (cc) increase in bladder volume led to an incremental raise of 1 Gy in bladder wall minimum dose received by the most irradiated 1 and 2 cc volumes (D1 and D2cc) of the bladder wall, respectively. An increase in bladder volume was associated with increased D1 and D2cc of bladder (both P<0.001, respectively) and rectal wall (P=0.150 and P=0.084, respectively), and decreased D1cc (P=0.003) and D2cc (P=0.001) of sigmoid wall, the maximum doses to the most minimally exposed 90 (D90) and 95% (D95) of the high risk-clinical target volume (HR-CTV; D90, P=0.010; D95, P=0.006). Patients with cumulative HR-CTV D90≤89.6 Gy had shorter median overall survival (OS) than those with cumulative HR-CTV D90>89.6 Gy (42.1 months vs. not reached, P=0.001). Patients with grade 2 acute urinary toxicity had significantly higher cumulative bladder wall D2cc than those with acute urinary toxicity<grade 2 (86.7±3.7 vs. 78.5±7.9 Gy; P=0.001). As the bladder volume increased, the dose to the bladder and rectal wall increase and dose to the sigmoid colon wall and HR-CTV decrease based on intracavitary brachytherapy. The higher dose of HR-CTV predicted better OS and the higher dose received by the bladder wall was associated with more grade 2 acute urinary toxicity.

Combination atezolizumab, bevacizumab, pemetrexed and carboplatin for metastatic EGFR mutated NSCLC after TKI failure

INTRODUCTION

Acquired resistance to TKI is an important unmet need in the management of EGFR mutated lung cancer. Recent clinical trial IMPower150 suggested that combination approach with VEGF inhibitor, check point inhibitor immunotherapy and platinum-based chemotherapy was effective in oncogene driven lung cancer. The current trial examined the efficacy of a modified regimen in an EGFR mutated cohort.

METHODS

An open-labelled, single arm, phase II study was conducted in patients with EGFR mutated NSCLC who had progressed on at least one EGFR TKI. For those with T790M mutation, radiological progression on osimertinib was required for enrolment. Patients were treated with combination atezolizumab (1200 mg), bevacizumab (7.5 mg/kg), pemetrexed (500 mg/m2) and carboplatin (AUC 5) given once every 3 weeks until progression.

RESULTS

Forty patients were enrolled. Median age was 62 (range 45-76) years. More than one half (23/40, 57.5%) had progressed on osimertinib. PD-L1 expression was < 1% in 52.5%. Median follow-up time was 17.8 months. ORR was 62.5%. Median PFS was 9.4 months (95% CI: 7.6 - 12.1). One year OS was 72.5% (95% CI: 0.56-0.83). Treatment related grade 3 or above adverse events (AE) occurred in 37.5% (15/40). Immune-related AE occurred in 32.5% (13/40) patients. Quality of life measures of function and symptoms did not change significantly throughout the course of treatments. Post-trial rechallenge with EGFR TKI containing regimen resulted in PFS of 5.8 months (95% CI 3.9-10.0 months).

CONCLUSION

Combination approach of atezolizumab, bevacizumab, pemetrexed and carboplatin achieved promising efficacy in metastatic EGFR mutated NSCLC after TKI failure. The results were comparable with taxane based regimen of IMPower150 while toxicity profile was improved.

Local Control After Stereotactic Body Radiation Therapy for Stage I Non-Small Cell Lung Cancer

PURPOSE

Numerous dose and fractionation schedules have been used to treat medically inoperable stage I non-small cell lung cancer (NSCLC) with stereotactic body radiation therapy (SBRT) or stereotactic ablative radiation therapy. We evaluated published experiences with SBRT to determine local control (LC) rates as a function of SBRT dose.

METHODS AND MATERIALS

One hundred sixty published articles reporting LC rates after SBRT for stage I NSCLC were identified. Quality of the series was assessed by evaluating the number of patients in the study, homogeneity of the dose regimen, length of follow-up time, and reporting of LC. Clinical data including 1, 2, 3, and 5-year tumor control probabilities for stages T1, T2, and combined T1 and T2 as a function of the biological effective dose were fitted to the linear quadratic, universal survival curve, and regrowth models.

RESULTS

Forty-six studies met inclusion criteria. As measured by the goodness of fit χ2/ndf, with ndf as the number of degrees of freedom, none of the models were ideal fits for the data. Of the 3 models, the regrowth model provides the best fit to the clinical data. For the regrowth model, the fitting yielded an α-to-β ratio of approximately 25 Gy for T1 tumors, 19 Gy for T2 tumors, and 21 Gy for T1 and T2 combined. To achieve the maximal LC rate, the predicted physical dose schemes when prescribed at the periphery of the planning target volume are 43 ± 1 Gy in 3 fractions, 47 ± 1 Gy in 4 fractions, and 50 ± 1 Gy in 5 fractions for combined T1 and T2 tumors.

CONCLUSIONS

Early-stage NSCLC is radioresponsive when treated with SBRT or stereotactic ablative radiation therapy. A steep dose-response relationship exists with high rates of durable LC when physical doses of 43-50 Gy are delivered in 3 to 5 fractions.

Association between homologous recombination deficiency and tumor mutational burden in lung cancer

e21043

Background: Homologous recombination (HR) is an important repair method for DNA double-strand damage. HR is involved with complex signaling pathways and multiple steps, including BRCA1/2. Homologous Recombination Deficiency (HRD) can be caused by the loss of function of BRCA1/2 proteins due to gene mutation. Tumor mutational burden (TMB) was indicated to involved with HRD, which is critical to the guidance of immunotherapy. Methods: Patients available with tumor specimen genomic testing for lung cancer were enrolled in this study. The sequencing library was captured using a 605-gene panel. Homologous recombination (HR)-related gene list included 102 genes. Genomic alterations of HR-related genes were assessed by next-generation sequencing assay, including nonsense, nonstop, frameshift, splice site, damaging missense mutations in somatic variants and pathogenic germline variants. Then, TMB was calculated by dividing the total number of mutations counted by the size of the coding region. Results: A total of 741 patients was enrolled and 182 of them (25.6%) had at least one genomic alteration of the HR genes. The top mutant HR genes included ATM (4.1%), DNMT3A (2.8%), ATR (1.8%), CHEK2 (1.5%), BRCA2 (1.5%), ABL1 (1.4%), FANCA (1.2%), RIF1 (1.1%), FANCI (1.1%), RAD50 (0.9%), BRCA1 (0.9%), and MRE11A (0.9%). The most common mutational type was missense mutation (69.2%), followed by frameshift (15.6%), and nonsense mutation (15.2%). The median age was 62 in the HRD group (age < 45:5.4%, 45-65:59.6%, > 65:34.9%) compared to 60 in the rest of the patients (age < 45:11.3%, 45-65:61.3%, > 65:27.4%). There were overall 57.5% males and 42.5% females in terms of gender. HRD group had a significantly higher rate than Non-HRD group in males (72.1% vs 52.8%, p < 0.01). The occurrence of HRD mutations was significantly correlated with a high level of TMB (p < 0.01). The median TMB of HRD group (7.9 muts/Mb, 95%CI:7.1-9.2 muts/Mb) was significantly higher than that of Non-HRD group (3.8 muts/Mb, 95%CI:3.3-4.2 muts/Mb). In addition, the upper quantile value (7.5 muts/Mb) was used to identify patients with high TMB. HRD group had a significantly higher rate of TMB-high patients than Non-HRD group (51.1% vs 17.0%, p < 0.01). Conclusions: Our study demonstrated genomic alterations of the HR genes in about one fourth’s lung cancer. Besides, there was a significant positive correlation between HRD mutations and TMB level. The significance of HRD genomic mutation on predicting the efficacy of immunotherapy deserves further study.

Deep learning to develop transcriptomic model for survival prediction in TCGA patients with hepatocellular carcinoma

e14057

Background: This study aimed to investigate the prognostic value of transcriptome and clinical data of Hepatocellular carcinoma (HCC) patients for overall survival (OS) by deep learning method. Methods: A total of 371 HCC patients with 20530 level three RNA-sequencing data were from The Cancer Genome Atlas (TCGA). Cox-nnet model, a deep learning model through an artificial neural network extension of the Cox regression model, was used for OS prediction. The patients were randomly split into train-set and test-set (7:3). In train-set, the significant genes associated with OS under univariate Cox regression were considered for modeling. Clinical parameters, including age, gender, pathologic stage, child pugh classification, creatinine level etc. were also considered. The Cox-nnet model was developed by cross-validation. Its discrimination was determined by the concordance index (CI) in the independent test-set and compared with multivariable Cox regression. The clustering method Uniform Manifold Approximation and Projection (UMAP) was used for revealing biological information from the hidden layer in the model. Results: In the train-set (n = 259), 1505 genes and two clinical variables (child pugh score and creatinine level) were significantly associated with OS (adjusted P-value < 0.05). To avoid overfitting, only 40 most significant genes were included in the Cox-nnet model. In the test-set (n = 112), the CI of Cox-nnet (0.76, se = 0.04) is better than the CI of multivariable Cox regression (0.71, se = 0.05). The difference between good or poor survival subgroups classified by Cox-nnet was remarkably significant ( P-value = 1e-4, median OS: 80.7 vs. 25.1 months). In the Cox-nnet model with all significant variables, the weights in the hidden layer were clustered by UMAP into 3 positive clusters and 2 negative clusters, which are enriched in GO/KEGG. The “cell cycle” and “complement and coagulation cascades” are the most important signal pathways in positive and negative clusters, respectively. Conclusions: Combining transcriptomic and clinical data, and with deep learning algorithm, we built and validated a robust model for survival prediction in HCC patients. Our study would be useful to explore the clinical implications in survival prediction and corresponding genetic mechanisms. Clinical trial information: 5U24CA143799, 5U24CA143835, 5U24CA143840, 5U24CA143843, 5U24CA143845, 5U24CA143848, 5U24CA1438.

Patterns of thyroid dysfunctions during treatment with immune checkpoint inhibitors (ICI) in 59 solid cancer patients

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Background: Immune checkpoint inhibitors (ICI) have now become the mainstay treatment in patients with many kinds of cancers. Thyroid dysfunction as the most common endocrine toxicity is poorly understood. This study aimed to report hypothyroidism and exam its changing dynamtic in our first series of patients treated with ICI. Methods: This is a retrospective study. Patients received nivolumab or pembrolizumab between July 2018 and December 2019 were considered. Patient must have euthyroidism within the 3 months before immunotherapy and those had previous use of levothyroxine were excluded. They were monitored by thyroid function tests every cycle until stopping ICI. Patients must have received at least 3 cycles of antibody treatment. Results: Among 89 patients treated, 59 met the inclusion criteria. There were 33 males, 26 females, including 26 (44.1%) nivolumab, and 33 (55.9%) pembrolizumab. Median age was 62 years [range: 27-88]). Cancer diagnoses observed were non small cell lung cancer 17(28.8%), small cell lung cancer 4 (6.8%),liver cancer 9 (15.3%), head and neck cancer 5 (8.5%), esophageal cancer4 (6.8%) colon cancer 3 (5.1%), nasopharygeal carcinoma 3 (5.1%) melanoma 3 (5.1%) and other cancers 11(18.6%). There were 9 patients (15.3%) developed a thyroid dysfunction, including 5 females. Four patients had thyrotoxicosis (median onset: 8 weeks) followed by hypothyroidism. There were three types of thyroid dysfunctions: the first type patients 3 (33.3%) had a brief time period of TSH flair (peak 17.4-57.8) after the first cycle of ICI, followed by TSH dramatic drop companied with rising fT4, which usually returned to normal level during 3-4 cycles of . The other 4 patients (44.4%) with thyroid dysfunction presented with remarkably elevated TSH (15.43-125.2) after 3.5-10 months’ treatment, followed by hypothyroidism development with a need of levothyroxine. The remaining 1 patient had a third type of thyroid dysfunction with elevated TSH, elavated more while the treatment continue, the patient should be given levothyroxine as soon as possible. Additionally, 1 patient developed hypopituitarism presented with both low level of TSH and fT4 after 10 month treatment. There was no significant difference in patient characteristics between patients with hypothyroidism and those without. Conclusions: There are heterogeneity in thyroid function and hypothyroidism after ICI. Before more experience is gained, frequent monitoring of thyroid function during ICI is warranted for prompt management of the hypothyroidism.

Depression in women breast cancer patients receiving radiation therapy: A pilot study

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Background: The purpose of this study is to study depression and its risk factors at baseline and explore the changes of depression status during the course of radiation therapy in breast patients. Methods: This is part of a prospective study of treatment toxicity and quality of life. Breast cancer patients, aged 18-year old and above requiring adjuvant radiation therapy were eligible. The primary endpoint depression was assessed by a self-addressed “depression” questionnaires according to NCI “PROMIS”. The Questionnaires were completed one day prior to, during and at the end of treatment. Patient, tumor and prior treatment factors were collected. Cancer specific symptoms were collected by treating physicians and graded according to NIH/NCI CTCAE v4.0. The variables of our interest included age, menopausal status, N-stage,pathology stage, immunohistochemisty, surgical approaches,margin,prior treatments and radiation models. Data are presented as mean (95% confidence interval) unless otherwise specified. Statistical significances were tested using generalized linear model, pearson correlation and t-text. Ps less than 0.05 were considered to be significant. Results: Between July 2019 and January 2020, a total of 185 patients enrolled and completed the PROMIS questionaires. Before RT commencement, 50/185 (27.0%) had some levels of depressive feeling including 40/185 (21.6%), 10/185 (5.4%), and 0/185 (0%) patients for “rarely” (score = 5-8), “sometimes” (score = 9-12), “often” (score = 13-16), and “always” (score 17-20), respectively. Interestingly, N stage and pathology staging group were significantly associated with the depression at baseline while age, menopausal status, immunohistochemistry, previous chemo cycles, chemo regimens and anti-Her2 taget therapy were not. At the end of RT, 51/149 (34.2%) patients had depression level changed, though the absolute lumped scores of depression did not change significantly (p = 0.437). Changes in depression during were significantly associated with menopausal status (p = 0.015) while grade 2 and above toxicities were not (p = 0.421). Conclusions: Depression feeling is not uncommon in breast patients receiving adjuvant radiation. Future study may identify patients with depression and associated risk factors so that proper intervention may be applied to improve long-term survival and quality of life in patients.

Predictors of Nodal and Metastatic Failure in Early Stage Non-small-cell Lung Cancer After Stereotactic Body Radiation Therapy

INTRODUCTION/BACKGROUND

Many patients with early stage non-small-cell lung cancer (ES-NSCLC) undergoing stereotactic body radiation therapy (SBRT) develop metastases, which is associated with poor outcomes. We sought to identify factors predictive of metastases after lung SBRT and created a risk stratification tool.

MATERIALS AND METHODS

We included 363 patients with ES-NSCLC who received SBRT; the median follow-up was 5.8 years. The following patient and tumor factors were retrospectively analyzed for their association with metastases (defined as nodal and/or distant failure): gender; age; lobe involved; centrality; previous NSCLC; smoking status; gross tumor volume (GTV); T-stage; histology; dose; minimum, maximum, and mean GTV dose; and parenchymal lung failure. A metastasis risk-score linear-model using beta coefficients from a multivariate Cox model was built.

RESULTS

A total of 111 (27.3%) of 406 lesions metastasized. GTV and dose were significantly associated with metastases on univariate and multivariate Cox proportional hazards modeling (P < .001 and hazard ratio [HR], 1.02 per mL; P < .05 and HR, 0.99 per Gy, respectively). Histology, T-stage, centrality, lung parenchymal failures, and previous NSCLC were not associated with development of metastasis. A metastasis risk-score model using GTV and prescription dose was built: risk score = (0.01611 × GTV) - (0.00525 × dose [BED₁₀]). Two risk-score cutoffs separating the cohort into low-, medium-, and high-risk subgroups were examined. The risk score identified significant differences in time to metastases between low-, medium-, and high-risk patients (P < .001), with 3-year estimates of 81.1%, 63.8%, and 38%, respectively.

CONCLUSION

GTV and radiation dose are associated with time to metastasis and may be used to identify patients at higher risk of metastasis after lung SBRT.

A model combining age, equivalent uniform dose and IL-8 may predict radiation esophagitis in patients with non-small cell lung cancer

BACKGROUND AND PURPOSE

To study whether cytokine markers may improve predictive accuracy of radiation esophagitis (RE) in non-small cell lung cancer (NSCLC) patients.

MATERIALS AND METHODS

A total of 129 patients with stage I-III NSCLC treated with radiotherapy (RT) from prospective studies were included. Thirty inflammatory cytokines were measured in platelet-poor plasma samples. Logistic regression was performed to evaluate the risk factors of RE. Stepwise Akaike information criterion (AIC) and likelihood ratio test were used to assess model predictions.

RESULTS

Forty-nine of 129 patients (38.0%) developed grade ≥2 RE. Univariate analysis showed that age, stage, concurrent chemotherapy, and eight dosimetric parameters were significantly associated with grade ≥2 RE (p < 0.05). IL-4, IL-5, IL-8, IL-13, IL-15, IL-1α, TGFα and eotaxin were also associated with grade ≥2 RE (p < 0.1). Age, esophagus generalized equivalent uniform dose (EUD), and baseline IL-8 were independently associated grade ≥2 RE. The combination of these three factors had significantly higher predictive power than any single factor alone. Addition of IL-8 to toxicity model significantly improves RE predictive accuracy (p = 0.019).

CONCLUSIONS

Combining baseline level of IL-8, age and esophagus EUD may predict RE more accurately. Refinement of this model with larger sample sizes and validation from multicenter database are warranted.

Histology, Tumor Volume, and Radiation Dose Predict Outcomes in NSCLC Patients After Stereotactic Ablative Radiotherapy

INTRODUCTION

It remains unclear if histology should be independently considered when choosing stereotactic ablative body radiotherapy dose prescriptions for NSCLC.

METHODS

The study population included 508 patients with 561 lesions between 2000 and 2016, of which 442 patients with 482 lesions had complete dosimetric information. Eligible patients had histologically or clinically diagnosed early-stage NSCLC and were treated with 3 to 5 fractions. The primary endpoint was in-field tumor control censored by either death or progression. Involved lobe control was also assessed.

RESULTS

At 6.7 years median follow-up, 3-year in-field control, involved lobe control, overall survival, and progression-free survival rates were 88.1%, 80.0%, 49.4%, and 37.2%, respectively. Gross tumor volume (GTV) (hazard ratio [HR] = 1.01 per mL, p = 0.0044) and histology (p = 0.0225) were independently associated with involved lobe failure. GTV (HR = 1.013, p = 0.001) and GTV dose (cutoff of 110 Gy, biologically effective dose with α/β = 10 [BED10], HR = 2.380, p = 0.0084) were independently associated with in-field failure. For squamous cell carcinomas, lower prescription doses were associated with worse in-field control (12 Gy × 4 or 10 Gy × 5 versus 18 Gy or 20 Gy × 3: HR = 3.530, p = 0.0447, confirmed by propensity score matching) and was independent of GTV (HR = 1.014 per mL, 95% confidence interval: 1.005-1.022, p = 0.0012). For adenocarcinomas, there were no differences in in-field control observed using the above dose groupings (p = 0.12 and p = 0.31, respectively).

CONCLUSIONS

In the absence of level I data, GTV and histology should be considered to personalize radiation dose for stereotactic ablative body radiotherapy. We suggest lower prescription doses (i.e., 12 Gy × 4 or 10 G × 5) should be avoided for squamous cell carcinomas if normal tissue tolerances are met.

A multiobjective Bayesian networks approach for joint prediction of tumor local control and radiation pneumonitis in nonsmall-cell lung cancer (NSCLC) for response-adapted radiotherapy

PURPOSE

Individualization of therapeutic outcomes in NSCLC radiotherapy is likely to be compromised by the lack of proper balance of biophysical factors affecting both tumor local control (LC) and side effects such as radiation pneumonitis (RP), which are likely to be intertwined. Here, we compare the performance of separate and joint outcomes predictions for response-adapted personalized treatment planning.

METHODS

A total of 118 NSCLC patients treated on prospective protocols with 32 cases of local progression and 20 cases of RP grade 2 or higher (RP2) were studied. Sixty-eight patients with 297 features before and during radiotherapy were used for discovery and 50 patients were reserved for independent testing. A multiobjective Bayesian network (MO-BN) approach was developed to identify important features for joint LC/RP2 prediction using extended Markov blankets as inputs to develop a BN predictive structure. Cross-validation (CV) was used to guide the MO-BN structure learning. Area under the free-response receiver operating characteristic (AU-FROC) curve was used to evaluate joint prediction performance.

RESULTS

Important features including single nucleotide polymorphisms (SNPs), micro RNAs, pretreatment cytokines, pretreatment PET radiomics together with lung and tumor gEUDs were selected and their biophysical inter-relationships with radiation outcomes (LC and RP2) were identified in a pretreatment MO-BN. The joint LC/RP2 prediction yielded an AU-FROC of 0.80 (95% CI: 0.70-0.86) upon internal CV. This improved to 0.85 (0.75-0.91) with additional two SNPs, changes in one cytokine and two radiomics PET image features through the course of radiotherapy in a during-treatment MO-BN. This MO-BN model outperformed combined single-objective Bayesian networks (SO-BNs) during-treatment [0.78 (0.67-0.84)]. AU-FROC values in the evaluation of the MO-BN and individual SO-BNs on the testing dataset were 0.77 and 0.68 for pretreatment, and 0.79 and 0.71 for during-treatment, respectively.

CONCLUSIONS

MO-BNs can reveal possible biophysical cross-talks between competing radiotherapy clinical endpoints. The prediction is improved by providing additional during-treatment information. The developed MO-BNs can be an important component of decision support systems for personalized response-adapted radiotherapy.

NF-κB functions as a molecular link between tumor cells and Th1/Tc1 T cells in the tumor microenvironment to exert radiation-mediated tumor suppression

Radiation modulates both tumor cells and immune cells in the tumor microenvironment to exert its anti-tumor activity; however, the molecular connection between tumor cells and immune cells that mediates radiation-exerted tumor suppression activity in the tumor microenvironment is largely unknown. We report here that radiation induces rapid activation of the p65/p50 and p50/p50 NF-κB complexes in human soft tissue sarcoma (STS) cells. Radiation-activated p65/p50 and p50/p50 bind to the TNFα promoter to activate its transcription in STS cells. Radiation-induced TNFα induces tumor cell death in an autocrine manner. A sublethal dose of Smac mimetic BV6 induces cIAP1 and cIAP2 degradation to increase tumor cell sensitivity to radiation-induced cell death in vitro and to enhance radiation-mediated suppression of STS xenografts in vivo. Inhibition of caspases, RIP1, or RIP3 blocks radiation/TNFα-induced cell death, whereas inhibition of RIP1 blocks TNFα-induced caspase activation, suggesting that caspases and RIP1 act sequentially to mediate the non-compensatory cell death pathways. Furthermore, we determined in a syngeneic sarcoma mouse model that radiation up-regulates IRF3, IFNβ, and the T cell chemokines CCL2 and CCL5 in the tumor microenvironment, which are associated with activation and increased infiltration of Th1/Tc1 T cells in the tumor microenvironment. Moreover, tumor-infiltrating T cells are in their active form since both the perforin and FasL pathways are activated in irradiated tumor tissues. Consequently, combined BV6 and radiation completely suppressed tumor growth in vivo. Therefore, radiation-induced NF-κB functions as a molecular link between tumor cells and immune cells in the tumor microenvironment for radiation-mediated tumor suppression.

Effect of Midtreatment PET/CT-Adapted Radiation Therapy With Concurrent Chemotherapy in Patients With Locally Advanced Non-Small-Cell Lung Cancer: A Phase 2 Clinical Trial

Importance

Our previous studies demonstrated that tumors significantly decrease in size and metabolic activity after delivery of 45 Gy of fractionated radiatiotherapy (RT), and that metabolic shrinkage is greater than anatomic shrinkage. This study aimed to determine whether 18F-fludeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) acquired during the course of treatment provides an opportunity to deliver higher-dose radiation to the more aggressive areas of the tumor to improve local tumor control without increasing RT-induced lung toxicity (RILT), and possibly improve survival.

Objective

To determine whether adaptive RT can target high-dose radiation to the FDG-avid tumor on midtreatment FDG-PET to improve local tumor control of locally advanced non-small-cell lung cancer (NSCLC).

Design, Setting, and Participants

A phase 2 clinical trial conducted at 2 academic medical centers with 42 patients who had inoperable or unresectable stage II to stage III NSCLC enrolled from November 2008, to May 2012. Patients with poor performance, more than 10% weight loss, poor lung function, and/or oxygen dependence were included, providing that the patients could tolerate the procedures of PET scanning and RT.

Intervention

Conformal RT was individualized to a fixed risk of RILT (grade >2) and adaptively escalated to the residual tumor defined on midtreatment FDG-PET up to a total dose of 86 Gy in 30 daily fractions. Medically fit patients received concurrent weekly carboplatin plus paclitaxel followed by 3 cycles of consolidation.

Main Outcomes and Measures

The primary end point was local tumor control. The trial was designed to achieve a 20% improvement in 2-year control from 34% of our prior clinical trial experience with 63 to 69 Gy in a similar patient population.

Results

The trial reached its accrual goal of 42 patients: median age, 63 years (range, 45-83 years); male, 28 (67%); smoker or former smoker, 39 (93%); stage III, 38 (90%). Median tumor dose delivered was 83 Gy (range, 63-86 Gy) in 30 daily fractions. Median follow-up for surviving patients was 47 months. The 2-year rates of infield and overall local regional tumor controls (ie, including isolated nodal failure) were 82% (95% CI, 62%-92%) and 62% (95% CI, 43%-77%), respectively. Median overall survival was 25 months (95% CI, 12-32 months). The 2-year and 5-year overall survival rates were 52% (95% CI, 36%-66%) and 30% (95% CI, 16%-45%), respectively.

Conclusions and Relevance

Adapting RT-escalated radiation dose to the FDG-avid tumor detected by midtreatment PET provided a favorable local-regional tumor control. The RTOG 1106 trial is an ongoing clinical trial to validate this finding in a randomized fashion.

Trial Registration

clinicaltrials.gov Identifier: NCT01190527.

Principal component analysis identifies patterns of cytokine expression in non-small cell lung cancer patients undergoing definitive radiation therapy

Background/Purpose

Radiation treatment (RT) stimulates the release of many immunohumoral factors, complicating the identification of clinically significant cytokine expression patterns. This study used principal component analysis (PCA) to analyze cytokines in non-small cell lung cancer (NSCLC) patients undergoing RT and explore differences in changes after hypofractionated stereotactic body radiation therapy (SBRT) and conventionally fractionated RT (CFRT) without or with chemotherapy.

Methods

The dataset included 141 NSCLC patients treated on prospective clinical protocols; PCA was based on the 128 patients who had complete CK values at baseline and during treatment. Patients underwent SBRT (n = 16), CFRT (n = 18), or CFRT (n = 107) with concurrent chemotherapy (ChRT). Levels of 30 cytokines were measured from prospectively collected platelet-poor plasma samples at baseline, during RT, and after RT. PCA was used to study variations in cytokine levels in patients at each time point.

Results

Median patient age was 66, and 22.7% of patients were female. PCA showed that sCD40l, fractalkine/C3, IP10, VEGF, IL-1a, IL-10, and GMCSF were responsible for most variability in baseline cytokine levels. During treatment, sCD40l, IP10, MIP-1b, fractalkine, IFN-r, and VEGF accounted for most changes in cytokine levels. In SBRT patients, the most important players were sCD40l, IP10, and MIP-1b, whereas fractalkine exhibited greater variability in CFRT alone patients. ChRT patients exhibited variability in IFN-γ and VEGF in addition to IP10, MIP-1b, and sCD40l.

Conclusions

PCA can identify potentially significant patterns of cytokine expression after fractionated RT. Our PCA showed that inflammatory cytokines dominate post-treatment cytokine profiles, and the changes differ after SBRT versus CFRT, with vs without chemotherapy. Further studies are planned to validate these findings and determine the clinical significance of the cytokine profiles identified by PCA.

Serum MicroRNA Signature Predicts Response to High-Dose Radiation Therapy in Locally Advanced Non-Small Cell Lung Cancer

PURPOSE

To assess the utility of circulating serum microRNAs (c-miRNAs) to predict response to high-dose radiation therapy for locally advanced non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Data from 80 patients treated from 2004 to 2013 with definitive standard- or high-dose radiation therapy for stages II-III NSCLC as part of 4 prospective institutional clinical trials were evaluated. Pretreatment serum levels of 62 miRNAs were measured by quantitative reverse transcription-polymerase chain reaction array. We combined miRNA data and clinical factors to generate a dose-response score (DRS) for predicting overall survival (OS) after high-dose versus standard-dose radiation therapy. Elastic net Cox regression was used for variable selection and parameter estimation. Model assessment and tuning parameter selection were performed through full cross-validation. The DRS was also correlated with local progression, distant metastasis, and grade 3 or higher cardiac toxicity using Cox regression, and grade 2 or higher esophageal and pulmonary toxicity using logistic regression.

RESULTS

Eleven predictive miRNAs were combined with clinical factors to generate a DRS for each patient. In patients with low DRS, high-dose radiation therapy was associated with significantly improved OS compared to treatment with standard-dose radiation therapy (hazard ratio 0.22). In these patients, high-dose radiation also conferred lower risk of distant metastasis and local progression, although the latter association was not statistically significant. Patients with high DRS exhibited similar rates of OS regardless of dose (hazard ratio 0.78). The DRS did not correlate with treatment-related toxicity.

CONCLUSIONS

Using c-miRNA signature and clinical factors, we developed a DRS that identified a subset of patients with locally advanced NSCLC who derive an OS benefit from high-dose radiation therapy. This DRS may guide dose escalation in a patient-specific manner.

Neoadjuvant twice daily chemoradiotherapy for esophageal cancer: Treatment-related mortality and long-term outcomes

OBJECTIVE

Because of the short potential doubling time of esophageal cancer, there is a theoretical benefit to using an accelerated radiation treatment schedule. This study evaluates outcomes and treatment-related mortality and morbidity of patients treated with neoadjuvant hyperfractionated accelerated chemoradiation for resectable esophageal cancer.

METHODS AND MATERIALS

Outcomes from 250 consecutive patients with resectable esophageal cancer treated with preoperative hyperfractionated accelerated chemoradiotherapy (45 Gy in 30 twice-daily fractions over 3 weeks) followed by planned transhiatal esophagectomy were analyzed. Grade 3 or greater treatment related toxicity, surgical complications, and treatment-related mortality were determined. Additionally, available surgical specimens were graded for pathological response to chemoradiation. Overall survival (OS) and locoregional control were calculated using the Kaplan-Meier method. The log rank test was used to determine statistical significance.

RESULTS

Median follow-up was 59 months for surviving patients; 87% of patients had adenocarcinoma and 13% had squamous cell carcinoma. Eleven percent of patients did not have surgery because of the development of metastases, declining performance status, or refusal. Twenty-seven patients were found to have unresectable and/or metastatic disease at the time of surgery. Overall, 10 of 223 operated patients died within 3 months, resulting in a perioperative mortality rate of 4%. Median OS was 28.4 months (95% confidence interval, 22.3-35.6 months) for all patients and 35.1 months (95% confidence interval, 27.4-47 months) for patients who underwent esophagectomy. There were 32 isolated locoregional failures with a 3-year locoregional control rate of 83%. Of 129 patients who had independent pathology review, 29% had complete response to treatment. This group had a median OS of 98.9 months and 3-year OS of 74%.

CONCLUSION

Neoadjuvant twice-daily chemoradiation for esophageal cancer is a safe and effective alternative to daily fractionation with low treatment-related mortality and long-term outcomes similar to standard fractionation courses.

Cardiac Events After Radiation Therapy: Combined Analysis of Prospective Multicenter Trials for Locally Advanced Non-Small-Cell Lung Cancer

Purpose Radiation therapy is a critical component in the care of patients with non-small-cell lung cancer (NSCLC), yet cardiac injury after treatment is a significant concern. Therefore, we wished to elucidate the incidence of cardiac events and their relationship to radiation dose to the heart. Patients and Materials Study eligibility criteria included patients with stage II to III NSCLC treated on one of four prospective radiation therapy trials at two centers from 2004 to 2013. All cardiac events were reviewed and graded per Common Terminology Criteria for Adverse Events (v4.03). The primary end point was the development of a grade ≥ 3 cardiac event. Results In all, 125 patients met eligibility criteria; median follow-up was 51 months for surviving patients. Median prescription dose was 70 Gy, 84% received concurrent chemotherapy, and 27% had pre-existing cardiac disease. Nineteen patients had a grade ≥ 3 cardiac event at a median of 11 months (interquartile range, 6 to 24 months), and 24-month cumulative incidence was 11% (95% CI, 5% to 16%). On multivariable analysis (MVA), pre-existing cardiac disease (hazard ratio [HR], 2.96; 95% CI, 1.07 to 8.21; P = .04) and mean heart dose (HR, 1.07/Gy; 95% CI, 1.02 to 1.13/Gy; P = .01) were significantly associated with grade ≥ 3 cardiac events. Analyzed as time-dependent variables on MVA analysis, both disease progression (HR, 2.15; 95% CI, 1.54 to 3.00) and grade ≥ 3 cardiac events (HR, 1.76; 95% CI, 1.04 to 2.99) were associated with decreased overall survival. However, disease progression (n = 71) was more common than grade ≥ 3 cardiac events (n = 19). Conclusion The 24-month cumulative incidence of grade ≥ 3 cardiac events exceeded 10% among patients with locally advanced NSCLC treated with definitive radiation. Pre-existing cardiac disease and higher mean heart dose were significantly associated with higher cardiac event rates. Caution should be used with cardiac dose to minimize risk of radiation-associated injury. However, cardiac risks should be balanced against tumor control, given the unfavorable prognosis associated with disease progression.

Early Assessment of Treatment Responses During Radiation Therapy for Lung Cancer Using Quantitative Analysis of Daily Computed Tomography

PURPOSE

To investigate early tumor and normal tissue responses during the course of radiation therapy (RT) for lung cancer using quantitative analysis of daily computed tomography (CT) scans.

METHODS AND MATERIALS

Daily diagnostic-quality CT scans acquired using CT-on-rails during CT-guided RT for 20 lung cancer patients were quantitatively analyzed. On each daily CT set, the contours of the gross tumor volume (GTV) and lungs were generated and the radiation dose delivered was reconstructed. The changes in CT image intensity (Hounsfield unit [HU]) features in the GTV and the multiple normal lung tissue shells around the GTV were extracted from the daily CT scans. The associations between the changes in the mean HUs, GTV, accumulated dose during RT delivery, and patient survival rate were analyzed.

RESULTS

During the RT course, radiation can induce substantial changes in the HU histogram features on the daily CT scans, with reductions in the GTV mean HUs (dH) observed in the range of 11 to 48 HU (median 30). The dH is statistically related to the accumulated GTV dose (R² > 0.99) and correlates weakly with the change in GTV (R² = 0.3481). Statistically significant increases in patient survival rates (P=.038) were observed for patients with a higher dH in the GTV. In the normal lung, the 4 regions proximal to the GTV showed statistically significant (P<.001) HU reductions from the first to last fraction.

CONCLUSION

Quantitative analysis of the daily CT scans indicated that the mean HUs in lung tumor and surrounding normal tissue were reduced during RT delivery. This reduction was observed in the early phase of the treatment, is patient specific, and correlated with the delivered dose. A larger HU reduction in the GTV correlated significantly with greater patient survival. The changes in daily CT features, such as the mean HU, can be used for early assessment of the radiation response during RT delivery for lung cancer.

Lower Incidence of Esophagitis in the Elderly Undergoing Definitive Radiation Therapy for Lung Cancer

INTRODUCTION

Most patients with lung cancer are elderly and poorly represented in randomized clinical trials. They are often undertreated because of concerns about their ability to tolerate aggressive treatment. We tested the hypothesis that elderly patients undergoing definitive lung radiation might tolerate treatment differently than younger patients.

METHODS

A total of 125 patients who underwent definitive lung radiotherapy were identified from a prospective institutional database (University of Michigan cohort). Logistic regression modeling was performed to assess the impact of age on esophagitis grade 2 or higher or grade 2 or higher and pneumonitis grade 3 or higher or grade 2 or higher, with adjustment for esophageal and lung dose, respectively, as well as for chemotherapy utilization, smoking status, and performance status. The analysis was validated in a large cohort of 691 patients from the Michigan Radiation Oncology Quality Consortium registry, an independent statewide prospective database.

RESULTS

In the University of Michigan cohort, multivariable regression models revealed a significant inverse correlation between age and rate of esophagitis for both toxicity levels, (adjusted OR = 0.93 for both models and 95% confidence intervals of 0.88-0.98 and 0.87-0.99), with areas under the curve of 0.747 and 0.721, respectively, demonstrating good fit. This same association was noted in the Michigan Radiation Oncology Quality Consortium cohort. There was no significant association between age and pneumonitis.

CONCLUSIONS

There is a lower incidence of esophagitis with increasing age even after adjustment for use of chemotherapy. This is a novel finding in thoracic oncology. No age dependence was noted for pulmonary toxicity. The elderly are able to tolerate definitive thoracic radiation well and should be offered this option when clinically warranted.

NF-κB acts as a molecular link between tumor cells and Th1/Tc1 T cells in the tumor microenvironment to exert radiation-mediated tumor suppression

Radiation is a local treatment for many types of solid cancers. About two thirds of cancer patients require radiation during the course of their disease treatment. Radiation modulates both tumor cells and immune cells in the tumor microenvironment to exert anti-tumor activity, but the molecular connection between tumor cells and immune cells that mediates radiation-exerted tumor suppression activity is largely unknown. We report here that radiation induces rapid activation of the p65/p50 and p50/p50 NF-κB complexes in human soft tissue sarcoma (STS) cells. Radiation-activated p65/p50 and p50/p50 bind to the TNFα promoter to activate its transcription in STS cells. Radiation-induced TNFα then induces tumor cell death in an autocrine manner. Smac mimetic BV6 induces cIAP1 and cIAP2 degradation to increase tumor cell sensitivity to radiation-induced cell death in vitro and to enhance radiation-mediated suppression of STS xenografts in vivo. Inhibition of caspases, RIP1, or RIP3 blocks radiation/TNFα-induced cell death, whereas inhibition of RIP1 blocks TNFα-induced caspase activation, suggesting that caspases and RIP1 act sequentially to mediate the non-compensatory cell death pathways. We determined in a syngeneic sarcoma mouse model that radiation up-regulates the NF-κB target genes IRF3, IFNβ, and the T cell chemokines CCL2 and CCL5 in the tumor microenvironment, which is associated with activation and increased infiltration of Th1/Tc1 T cells in the tumor microenvironment. Consequently, combined BV6 and radiation completely suppressed tumor growth in vivo. Radiation-induced NF-κB functions as a molecular link between tumor cells and immune cells in the tumor microenvironment for radiation mediated tumor suppression.

Review of evolving etiologies, implications and treatment strategies for the superior vena cava syndrome

Superior vena cava syndrome (SVCS) is a relatively common sequela of mediastinal malignancies and may cause significant patient distress. SVCS is a medical emergency if associated with laryngeal or cerebral edema. The etiologies and management of SVCS have evolved over time. Non-malignant SVCS is typically caused by infectious etiologies or by thrombus in the superior vena cava and can be managed with antibiotics or anti-coagulation therapy, respectively. Radiation therapy (RT) has long been a mainstay of treatment of malignant SVCS. Chemotherapy has also been used to manage SVCS. In the past 20 years, percutaneous stenting of the superior vena cava has emerged as a viable option for SVCS symptom palliation. RT and chemotherapy are still the only modalities that can provide curative treatment for underlying malignant etiologies of SVCS. The first experiences with treating SVCS with RT were reported in the 1970’s, and several advances in RT delivery have subsequently occurred. Hypo-fractionated RT has the potential to be a more convenient therapy for patients and may provide equal or superior control of underlying malignancies. RT may be combined with stenting and/or chemotherapy to provide both immediate symptom palliation and long-term disease control. Clinicians should tailor therapy on a case-by-case basis. Multi-disciplinary care will maximize treatment expediency and efficacy.

Personalized dose selection in radiation therapy using statistical models for toxicity and efficacy with dose and biomarkers as covariates

Selection of dose for cancer patients treated with radiation therapy (RT) must balance the increased efficacy with the increased toxicity associated with higher dose. Historically, a single dose has been selected for a population of patients (e.g., all stage III non-small cell lung cancer). However, the availability of new biologic markers for toxicity and efficacy allows the possibility of selecting a more personalized dose. We consider the use of statistical models for toxicity and efficacy as a function of RT dose and biomarkers to select an optimal dose for an individual patient, defined as the dose that maximizes the probability of efficacy minus the sum of weighted toxicity probabilities. This function can be shown to be equal to the expected value of the utility derived from a particular family of bivariate outcome utility matrices. We show that if dose is linearly related to the probability of toxicity and efficacy, then any marker that only acts additively with dose cannot improve efficacy, without also increasing toxicity. Using a dataset of lung cancer patients treated with RT, we illustrate this approach and compare it to non-marker-based dose selection. Because typical metrics used in evaluating new markers (e.g., area under the ROC curve) do not directly address the ability of a marker to improve efficacy at a fixed probability of toxicity, we utilize a simulation study to assess the effects of marker-based dose selection on toxicity and efficacy outcomes.

Non-small cell lung cancer

Most patients with non-small cell lung cancer (NSCLC) are diagnosed with advanced cancer. These guidelines only include information about stage IV NSCLC. Patients with widespread metastatic disease (stage IV) are candidates for systemic therapy, clinical trials, and/or palliative treatment. The goal is to identify patients with metastatic disease before initiating aggressive treatment, thus sparing these patients from unnecessary futile treatment. If metastatic disease is discovered during surgery, then extensive surgery is often aborted. Decisions about treatment should be based on multidisciplinary discussion.

Impact of fraction size on lung radiation toxicity: hypofractionation may be beneficial in dose escalation of radiotherapy for lung cancers

PURPOSE

To assess how fraction size impacts lung radiation toxicity and therapeutic ratio in treatment of lung cancers.

METHODS AND MATERIALS

The relative damaged volume (RDV) of lung was used as the endpoint in the comparison of various fractionation schemes with the same normalized total dose (NTD) to the tumor. The RDV was computed from the biologically corrected lung dose-volume histogram (DVH), with an alpha/beta ratio of 3 and 10 for lung and tumor, respectively. Two different (linear and S-shaped) local dose-effect models that incorporated the concept of a threshold dose effect with a single parameter D(L50) (dose at 50% local dose effect) were used to convert the DVH into the RDV. The comparison was conducted using four representative DVHs at different NTD and D(L50) values.

RESULTS

The RDV decreased with increasing dose/fraction when the NTD was larger than a critical dose (D(CR)) and increased when the NTD was less than D(CR). The D(CR) was 32-50 Gy and 58-87 Gy for a small tumor (11 cm(3)) for the linear and S-shaped local dose-effect models, respectively, when D(L50) was 20-30 Gy. The D(CR) was 66-97 Gy and 66-99 Gy, respectively, for a large tumor (266 cm(3)). Hypofractionation was preferred for small tumors and higher NTDs, and conventional fractionation was better for large tumors and lower NTDs. Hypofractionation might be beneficial for intermediate-sized tumors when NTD = 80-90 Gy, especially if the D(L50) is small (20 Gy).

CONCLUSION

This computational study demonstrated that hypofractionated stereotactic body radiotherapy is a better regimen than conventional fractionation in lung cancer patients with small tumors and high doses, because it generates lower RDV when the tumor NTD is kept unchanged.

Using fluorodeoxyglucose positron emission tomography to assess tumor volume during radiotherapy for non-small-cell lung cancer and its potential impact on adaptive dose escalation and normal tissue sparing

PURPOSE

To quantify changes in fluorodeoxyglucose (FDG)-avid tumor volume on positron emission tomography/computed tomography (PET/CT) during the course of radiation therapy and examine its potential use in adaptive radiotherapy for tumor dose escalation or normal tissue sparing in patients with non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

As part of a pilot study, patients with Stage I-III NSCLC underwent FDG-PET/CT before radiotherapy (RT) and in mid-RT (after 40-50 Gy). Gross tumor volumes were contoured on CT and PET scans obtained before and during RT. Three-dimensional conformal RT plans were generated for each patient, first using only pretreatment CT scans. Mid-RT PET volumes were then used to design boost fields.

RESULTS

Fourteen patients with FDG-avid tumors were assessed. Two patients had a complete metabolic response, and 2 patients had slightly increased FDG uptake in the adjacent lung tissue. Mid-RT PET scans were useful in the 10 remaining patients. Mean decreases in CT and PET tumor volumes were 26% (range, +15% to -75%) and 44% (range, +10% to -100%), respectively. Designing boosts based on mid-RT PET allowed for a meaningful dose escalation of 30-102 Gy (mean, 58 Gy) or a reduction in normal tissue complication probability (NTCP) of 0.4-3% (mean, 2%) in 5 of 6 patients with smaller yet residual tumor volumes.

CONCLUSIONS

Tumor metabolic activity and volume can change significantly after 40-50 Gy of RT. Using mid-RT PET volumes, tumor dose can be significantly escalated or NTCP reduced. Clinical studies evaluating patient outcome after PET-based adaptive RT are ongoing.

Time to treatment in patients with stage III non-small cell lung cancer

PURPOSE

To determine whether time to treatment (TTT) has an effect on overall survival (OS) in patients with unresectable or medically inoperable Stage III non-small cell lung cancer (NSCLC) and whether patient or treatment factors are associated with TTT.

METHODS AND MATERIALS

Included in the study were 237 consecutive patients with Stage III NSCLC treated at University of Michigan Hospital (UM) or the Veterans Affairs Ann Arbor Healthcare System (VA). Patients were treated with either palliative or definitive radiotherapy and radiotherapy alone (n = 106) or either sequential (n = 69) or concurrent chemoradiation (n = 62). The primary endpoint was OS.

RESULTS

Median follow-up was 69 months, and median TTT was 57 days. On univariate analysis, the risk of death did not increase significantly with longer TTT (p = 0.093). However, subset analysis showed that there was a higher risk of death with longer TTT in patients who survived >or= 5 years (p = 0.029). Younger age (p = 0.027), male sex (p = 0.013), lower Karnofsky Performance Score (KPS) (p = 0.002), and treatment at the VA (p = 0.001) were significantly associated with longer TTT. However, on multivariate analysis, only lower KPS remained significantly associated with longer TTT (p = 0.003).

CONCLUSION

Time to treatment is significantly associated with OS in patients with Stage III NSCLC who lived longer than 5 years, although it is not a significant factor in Stage III patients as a whole. Lower KPS is associated with longer TTT.

Elevation of plasma TGF-beta1 during radiation therapy predicts radiation-induced lung toxicity in patients with non-small-cell lung cancer: a combined analysis from Beijing and Michigan

PURPOSE

To test whether radiation-induced elevations of transforming growth factor-beta1 (TGF-beta1) during radiation therapy (RT) correlate with radiation-induced lung toxicity (RILT) in patients with non-small-cell lung cancer (NSCLC) and to evaluate the ability of mean lung dose (MLD) to improve the predictive power.

METHODS AND MATERIALS

Eligible patients included those with Stage I-III NSCLC treated with RT with or without chemotherapy. Platelet-poor plasma was obtained pre-RT and at 4-5 weeks (40-50 Gy) during RT. TGF-beta1 was measured using an enzyme-linked immunosorbent assay. The primary endpoint was > or = Grade 2 RILT. Mann-Whitney U test, logistic regression, and chi-square were used for statistical analysis.

RESULTS

A total of 165 patients were enrolled in this study. The median radiation dose was 60 Gy, and the median MLD was 15.3 Gy. Twenty-nine patients (17.6%) experienced RILT. The incidence of RILT was 46.2% in patients with a TGF-beta1 ratio > 1 vs. 7.9% in patients with a TGF-beta1 ratio < or = 1 (p < 0.001), and it was 42.9% if MLD > 20 Gy vs. 17.4% if MLD < or = 20 Gy (p = 0.024). The incidence was 4.3% in patients with a TGF-beta1 ratio < or = 1 and MLD < or = 20 Gy, 47.4% in those with a TGF-beta1 ratio >1 or MLD > 20 Gy, and 66.7% in those with a TGF-beta1 ratio >1 and MLD > 20 Gy (p < 0.001).

CONCLUSIONS

Radiation-induced elevation of plasma TGF-beta1 level during RT is predictive of RILT. The combination of TGF- beta1 and MLD may help stratify the patients for their risk of RILT.

Radiation produces differential changes in cytokine profiles in radiation lung fibrosis sensitive and resistant mice

Background

Recent research has supported that a variety of cytokines play important roles during radiation-induced lung toxicity. The present study is designed to investigate the differences in early cytokine induction after radiation in sensitive (C57BL/6) and resistant mice (C3H).

Results

Twenty-two cytokines in the lung tissue homogenates, bronchial lavage (BAL) fluids, and serum from 3, 6, 12, 24 hrs to 1 week after 12 Gy whole lung irradiation were profiled using a microsphere-based multiplexed cytokine assay. The majority of cytokines had similar baseline levels in C57BL/6 and C3H mice, but differed significantly after radiation. Many, including granulocyte colony-stimulating factor (G-CSF), interleukin-6 (IL-6), and keratinocyte-derived chemokine (KC) were elevated significantly in specimens from both strains. They usually peaked at about 3–6 hrs in C57BL/6 and 6–12 hrs in C3H. At 6 hrs in lung tissue, G-CSF, IL-6, and KC increased 6, 8, and 11 fold in C57BL/6 mice, 4, 3, and 3 fold in the C3H mice, respectively. IL-6 was 10-fold higher at 6 hrs in the C57BL/6 BAL fluid than the C3H BAL fluid. MCP-1, IP-10, and IL-1α also showed some differences between strains in the lung tissue and/or serum. For the same cytokine and within the same strain of mice, there were significant linear correlations between lung tissue and BAL fluid levels (R² ranged 0.46–0.99) and between serum and tissue (R² ranged 0.56–0.98).

Conclusion

Radiation induced earlier and greater temporal changes in multiple cytokines in the pulmonary fibrosis sensitive mice. Positive correlation between serum and tissue levels suggests that blood may be used as a surrogate marker for tissue.