Texture analysis as a predictor of radiation-induced xerostomia in head and neck patients undergoing IMRT

PURPOSE

Image texture analysis (TA) is a heterogeneity quantifying approach that cannot be appreciated by the naked eye, and early evidence suggests that TA has great potential in the field of oncology. The aim of this study is to evaluate parotid gland texture analysis (TA) combined with formal dosimetry as a factor for predicting severe late xerostomia in patients undergoing radiation therapy for head and neck cancers.

METHODS

We performed a retrospective analysis of patients treated at our Radiation Oncology Unit between January 2010 and December 2015, and selected the patients whose normal dose constraints for the parotid gland (mean dose < 26 Gy for the bilateral gland) could not be satisfied due to the presence of positive nodes close to the parotid glands. The parotid gland that showed the higher V30 was contoured on CT simulation and analysed with LifeX Software©. TA parameters included features of grey-level co-occurrence matrix (GLCM), neighbourhood grey-level dependence matrix (NGLDM), grey-level run length matrix (GLRLM), grey-level zone length matrix (GLZLM), sphericity, and indices from the grey-level histogram. We performed a univariate and multivariate analysis between all the texture parameters, the volume of the gland, the normal dose parameters (V30 and Mean Dose), and the development of severe chronic xerostomia.

RESULTS

Seventy-eight patients were included and 25 (31%) developed chronic xerostomia. The TA parameters correlated with severe chronic xerostomia included V30 (OR 5.63), Dmean (OR 5.71), Kurtosis (OR 0.78), GLCM Correlation (OR 1.34), and RLNU (OR 2.12). The multivariate logistic regression showed a significant correlation between V30 (0.001), GLCM correlation (p: 0.026), RLNU (p: 0.011), and chronic xerostomia (p < 0.001, R2:0.664).

CONCLUSIONS

Xerostomia represents an important cause of morbidity for head and neck cancer survivors after radiation therapy, and in certain cases normal dose constraints cannot be satisfied. Our results seem promising as texture analysis could enhance the normal dose constraints for the prediction of xerostomia.

HLA Expression Correlates to the Risk of Immune Checkpoint Inhibitor-Induced Pneumonitis

Tumor-infiltrating T cell rescue by programmed cell death receptor-1 (PD-1)/PD-1 ligand-1 (PD-L1) immune checkpoint blockade is a recommended treatment for malignant diseases, including metastatic non-small-cell lung cancer (mNSCLC), malignant melanoma (MM), head and neck, kidney, and urothelial cancer. Monoclonal antibodies (mAbs) against either PD-1 or PD-L1 are active agents for these patients; however, their use may be complicated by unpredictable immune-related adverse events (irAEs), including immune-related pneumonitis (IRP). We carried out a retrospective multi-institutional statistical analysis to investigate clinical and biological parameters correlated with IRP rate on a cohort of 256 patients who received real-world treatment with PD-1/PD-L1 blocking mAbs. An independent radiological review board detected IRP in 29 patients. We did not find statistical IRP rate correlation with gender, tumor type, specific PD-1 or PD-L1 blocking mAbs, radiation therapy, inflammatory profile, or different irAEs. A higher IRP risk was detected only in mNSCLC patients who received metronomic chemotherapy +/- bevacizumab compared with other treatments prior PD-1/PD-L1 blockade. Moreover, we detected a strong correlation among the IRP rate and germinal expression of HLA-B*35 and DRB1*11, alleles associated to autoimmune diseases. Our findings may have relevant implications in predicting the IRP rate in mNSCLC patients receiving PD-1/PD-L1 blockade and need to be validated on a larger patient series.

Magnetic-Resonance-Imaging Texture Analysis Predicts Early Progression in Rectal Cancer Patients Undergoing Neoadjuvant Chemoradiation

BACKGROUND

We hypothesized that texture analysis (TA) from the preoperative MRI can predict early disease progression (ePD), defined as the percentage of patients who relapsed or showed distant metastasis within three months from the radical surgery, in patients with locally advanced rectal cancer (LARC, stage II and III, AJCC) undergoing neoadjuvant chemoradiotherapy (C-RT).

METHODS

This retrospective monoinstitutional cohort study included 49 consecutive patients in total with a newly diagnosed rectal cancer. All the patients underwent baseline abdominal MRI and CT scan of the chest and abdomen to exclude distant metastasis before C-RT. Texture parameters were extracted from MRI performed before C-RT (T1, DWI, and ADC sequences) using LifeX Software, a dedicated software for extracting texture parameters from radiological imaging. We divided the cohort in a training set of 34 patients and a validation set of 15 patients, and we tested the data sets for homogeneity, considering the clinical variables. Then we performed univariate and multivariate analysis, and a ROC curve was also generated.

RESULTS

Thirteen patients (26.5%) showed an ePD, three of whom with lung metastases and ten with liver relapse. The model was validated based on the prediction accuracy calculated in a previously unseen set of 15 patients. The prediction accuracy of the generated model was 82% (AUC = 0.853) in the training and 80% (AUC = 0.833) in the validation cohort. The only significant features at multivariate analysis was DWI GLCM Correlation (OR: 0.239, p < 0.001).

CONCLUSION

Our results suggest that TA could be useful to identify patients that may develop early progression.

Radiomics in the Setting of Neoadjuvant Radiotherapy: A New Approach for Tailored Treatment

INTRODUCTION

Neoadjuvant radiotherapy is currently used mainly in locally advanced rectal cancer and sarcoma and in a subset of non-small cell lung cancer and esophageal cancer, whereas in other diseases it is under investigation. The evaluation of the efficacy of the induction strategy is made possible by performing imaging investigations before and after the neoadjuvant therapy and is usually challenging. In the last decade, texture analysis (TA) has been developed to help the radiologist to quantify and identify the parameters related to tumor heterogeneity, which cannot be appreciated by the naked eye. The aim of this narrative is to review the impact of TA on the prediction of response to neoadjuvant radiotherapy and or chemoradiotherapy.

MATERIALS AND METHODS

Key references were derived from a PubMed query. Hand searching and ClinicalTrials.gov were also used.

RESULTS

This paper contains a narrative report and a critical discussion of radiomics approaches in different fields of neoadjuvant radiotherapy, including esophageal cancer, lung cancer, sarcoma, and rectal cancer.

CONCLUSIONS

Radiomics can shed a light on the setting of neoadjuvant therapies that can be used to tailor subsequent approaches or even to avoid surgery in the future. At the same, these results need to be validated in prospective and multicenter trials.

Role of perilesional edema and tumor volume in the prognosis of non-small cell lung cancer (NSCLC) undergoing radiosurgery (SRS) for brain metastases

AIM

To assess the role of perilesional edema (PE) in non-small cell lung carcinoma (NSCLC) brain metastases (BM) undergoing radiosurgery (SRS).

METHODS

This series includes 46 patients with 1-2 BM treated with SRS, selected out of all patients referred for radiotherapy (RT) for BMs over 5 years (2013 to 2017). Both the PE and gross tumor volume (GTV) were contoured on MRI images, and the PE/GTV ratio and PE + GTV value (TV, total volume) were calculated. Our clinical endpoints were brain recurrence free-survival, divided into local brain control (in field, LBC) and distant brain control (out of field, DBC) and overall survival (OS). We analyzed the role of the previously described volumetric parameters and of known clinical prognosticators (disease specific GPA, DS-GPA; chemotherapy, CHT) with Cox regression analyses.

RESULTS

Only four patients (9%) developed in-field progression, whereas 10 patients (22%) showed new out-of-field BM and thirty-eight patients died in the follow up (83%). In univariate analysis, both volumetric parameters and clinical parameters were correlated with DBC and OS, whereas we did not find any correlation with LBC. In the multivariate analysis of DBC, the significant parameters were PE/GTV ratio (HR 0.302), sex (HR 0.131), and DS-GPA (HR 0.261). The OS multivariate analysis showed that the only significant parameters were DS-GPA (HR 0.478) and TV (HR: 1.038).

CONCLUSION

Our study, although with the limitations of a monocentric retrospective study analyzing a small cohort of patients, suggests the role of PE/GTV ratio for the development of new BMs. TV also seems to be correlated with OS, together with known clinical prognosticators. These findings, if validated in a larger prospective dataset, could help in selecting patients for the most suitable RT modality (or systemic therapy approach).

Endorectal Ultrasound and Magnetic Resonance Imaging for Rectal Cancer Staging: A Modern Multimodality Approach

Preoperative staging represents a crucial point for the management, type of surgery, and candidacy for neoadjuvant therapy in patient with rectal cancer. The most recent clinical guidelines in oncology recommend an accurate preoperative evaluation in order to address early and advanced tumors to different therapeutic options. In particular, potential pitfalls may occur in the assessment of T3 tumors, which represents the most common stage at diagnosis. The depth of tumor invasion is known to be an important prognostic factor in rectal carcinoma; as a consequence, the T3 imaging classification has a substantial importance for treatment strategy and patient survival. However, the differentiation between tumor invasion of perirectal fat and mesorectal desmoplastic reactions remains a main goal for radiologists. Magnetic resonance imaging (MRI) is actually considered as the best imaging modality for rectal cancer staging. Although the endorectal ultrasound (ERUS) is the preferred staging method for early tumors, it could also be useful in identifying perirectal fat invasion. Moreover, the addiction of diffusion weighted imaging (DWI) improves the diagnostic performance of MRI in rectal cancer staging by adding functional information about rectal tumor and adjacent mesorectal tissues. This study investigated the diagnostic performance of conventional MRI alone, in combination with the DWI technique and ERUS in order to assess the best diagnostic imaging combination for rectal cancer staging.

Bone texture analysis using CT-simulation scans to individuate risk parameters for radiation-induced insufficiency fractures

This study deals with the role of texture analysis as a predictive factor of radiation-induced insufficiency fractures in patients undergoing pelvic radiation.

INTRODUCTION

This study aims to assess the texture analysis (TA) of computed tomography (CT) simulation scans as a predictive factor of insufficiency fractures (IFs) in patients with pelvic malignancies undergoing radiation therapy (RT).

METHODS

We performed an analysis of patients undergoing pelvic RT from January 2010 to December 2014, 24 of whom had developed pelvic bone IFs. We analyzed CT-simulation images using ImageJ macro software and selected two regions of interest (ROIs), which are L5 body and the femoral head. TA parameters included mean (m), standard deviation (SD), skewness (sk), kurtosis (k), entropy (e), and uniformity (u). The IFs patients were compared (1:2 ratio) with controlled patients who had not developed IFs and matched for sex, age, menopausal status, type of tumor, use of chemotherapy, and RT dose. A reliability test of intra- and inter-reader ROI TA reproducibility with the intra-class correlation coefficient (ICC) was performed. Univariate and multivariate analyses (logistic regression) were applied for TA parameters observed both in the IFs and the controlled groups.

RESULTS

Inter- and intra-reader ROI TA was highly reproducible (ICC > 0.90). Significant TA parameters on paired t test included L5 m (p = 0.001), SD (p = 0.002), k (p = 0.006), e (p = 0.004), and u (p = 0.015) and femoral head m (p < 0.001) and SD (p = 0.001), whereas on logistic regression analysis, L5 e (p = 0.003) and u (p = 0.010) and femoral head m (p = 0.027), SD (p = 0.015), and sex (p = 0.044).

CONCLUSIONS

In our experience, bone CT TA could be correlated to the risk of radiation-induced IFs. Studies on a large patient series and methodological refinements are warranted.

3D bone texture analysis as a potential predictor of radiation-induced insufficiency fractures

BACKGROUND

The aim of our work is to assess the potential role of texture analysis (TA), applied to computed tomography (CT) simulation scans, in relation to the development of insufficiency fractures (IFs) in patients undergoing radiation therapy (RT) for pelvic malignancies.

METHODS

We analyzed patients undergoing pelvic RT from Jan-2010 to Dec-2016, 31 of whom had developed IFs of the pelvis. We analyzed CT simulation scans using LifeX Software©, and in particular we selected three regions of interest (ROI): L5 body, the sacrum and both the femoral heads. The ROI were automatically contoured using the treatment planning software Raystation©. TA parameters included parameters from the gray-level histogram, indices from sphericity and from the matrix of GLCM (gray level co-occurrence matrix). The IFs patients were matched (1:1 ratio) with control patients who had not developed IFs, and were matched for age, sex, type of tumor, menopausal status, RT dose and use of chemotherapy. Univariate and multivariate analyses (logistic regression) were used for statistical analysis.

RESULTS

Significant TA parameters on univariate analysis included both parameters from the histogram distribution, as well from the matrix of GLCM. On logistic regression analysis the significant parameters were L5-energy [P=0.033, odds ratio (OR): 1.997, 95% CI: 1.059-3.767] and FH-Skewness (P=0.014, OR: 2.338, 95% CI: 1.191-4.591), with a R2: 0.268. A ROC curve was generated from the binary logistic regression, and the AUC was 0.741 (95% CI: 0.627-0.855, P=0.001, S.E.: 0.058).

CONCLUSIONS

In our experience, 3D-bone CT TA can be used to stratify the risk of the patients to develop radiation-induced IFs. A prospective study will be conducted to validate these findings.

Prognostic Value of MR Imaging Texture Analysis in Brain Non-Small Cell Lung Cancer Oligo-Metastases Undergoing Stereotactic Irradiation

BACKGROUND : Stereotactic irradiation is widely used in brain oligo-metastases treatment. The aim of this study is to evaluate the prognostic value of magnetic resonance imaging (MRI) texture analysis (TA) of brain metastases (BM) of non-small cell lung cancer (NSCLC). MATERIALS AND METHODS : This study included thirty-eight consecutive patients undergoing stereotactic irradiation, that is, stereotactic fractionated radiotherapy (SRT) or radiosurgery (SRS), from January 2011 to December 2014 for 1-2 brain BM from NSCLC. Whole-brain radiotherapy (WBRT) was not delivered. The diagnostic MRI DICOM (Digital Imaging and Communications in Medicine) images were collected and analyzed with a homemade ImageJ macro, and typical TA parameters (mean, standard deviation, skewness, kurtosis, entropy, and uniformity) were evaluated for: brain progression-free survival; modality of brain metastatic progression (local progression or/and new metastases); and overall survival, after SRT/SRS.

RESULTS

After SRT/SRS 14 patients (36.8%) experienced recurrence in the brain, with a recurrence in the irradiated site (five patients, 13.2%), new metastases (11 patients, 28.9%), local recurrence and new metastases (two patients, 5.25%). Nineteen patients (50%) died of tumor progression or other causes. Entropy and uniformity were significantly associated with local progression, whereas kurtosis was significantly associated with both local progression and new brain metastases. CONCLUSIONS : These results appear promising, since the knowledge of factors correlated with the modality of brain progression after stereotactic irradiation of brain oligo-metastatic foci of NSCLC might help in driving the best treatment in these patients (association of SRT/SRS with WBRT? Increase of SRT/SRS dose?). Our preliminary data needs confirmation in large patient series.

Mood Disorder in Cancer Patients Undergoing Radiotherapy During the COVID-19 Outbreak

Introduction: Novel coronavirus (COVID-19) is having a devastating psychological impact on patients, especially patients with cancer. This work aims to evaluate mood disorders of cancer patients undergoing radiation therapy during COVID-19 in comparison with cancer patients who underwent radiation therapy in 2019. Materials and Methods: We included all the patients undergoing radiation therapy at our department in two-time points (once a week for a month in May 2019) and during the COVID-19 outbreak (in April 2020). All the patients were asked to fulfill a validated questionnaire (STAI-Y1, State trait anxiety inventory scale), the Symptom Distress thermometer (SDT) (from 0 to 10 score), and the Beck Depression Inventory v.2 (BDI-2). We took into account the COVID-19 outbreak and also sex, age, week of radiation treatment, and disease. Results: We included 458 patients (220 males and 238 females), with a median age of 64 years. STAI-Y1 median score was 40 (mean 41,3, range 19-79), whereas the median score of SDT was five and BDI-2 median score was 11. STAI-Y1, SDT, and BDI-2 were significantly correlated with the COVID-19 outbreak (p < 0,001 for all the tests), sex (p: 0,016 for STAI-Y1, p < 0.001 for SDT, p:0.013 for BDI-2), week of treatment (p: 0.012 for STAI-Y1 and p: 0.031 for SDT), and disease (p:0.015 for STAI-Y1, p < 0.001 for SDT and p:0.020 for BDI-2). Conclusions: The prevalence of mood disorders in patients undergoing radiation therapy is higher than expected and even higher during the COVID-19 outbreak. These measurements could be useful as a baseline to start medical humanities programs to decrease these scores.

4D CT analysis of organs at risk (OARs) in stereotactic radiotherapy

Internal organs at risk volumes (IRV) represent the propagation of organs at risk (OARs) in 4DCT. Sixty consecutive patients that underwent 4DCT for thoracic stereotactic radiotherapy were analyzed and IRVs for heart, trachea, esophagus, bronchial tree, great vessels, and spinal cord were calculated. IRVs were then tested for the respect of dose constraints. IRVs were significantly bigger than standard OARs (p-value <0.001 for all the IRVs). IRVs that did not respect the dose constraints were, respectively, 7/60 (11.7%) for Heart IRV, 6/60 (10%) for Esophagus IRV, 11/60 (18.3%) for Trachea IRV, 16/60 (26.6%) for Bronchial Tree and 0/60 (0%) for great vessel and spinal cord IRV. In the subset of central targets, the percentage of plans that can be unacceptable taking into consideration OARs motion reaches 42%. The correlation of IRVs with clinical parameters and toxicity deserves future investigations in prospective trials.

The role of feature-based radiomics for predicting response and radiation injury after stereotactic radiation therapy for brain metastases: A critical review by the Young Group of the Italian Association of Radiotherapy and Clinical Oncology (yAIRO)

INTRODUCTION

differential diagnosis of tumor recurrence and radiation injury after stereotactic radiotherapy (SRT) is challenging. The advances in imaging techniques and feature-based radiomics could aid to discriminate radionecrosis from progression.

METHODS

we performed a systematic review of current literature, key references were obtained from a PubMed query. Data extraction was performed by 3 researchers and disagreements were resolved with a discussion among the authors.

RESULTS

we identified 15 retrospective series, one prospective trial, one critical review and one editorial paper. Radiomics involves a wide range of imaging features referred to necrotic regions, rate of contrast-enhancing area or the measure of edema surrounding the metastases. Features were mainly defined through a multistep extraction/reduction/selection process and a final validation and comparison.

CONCLUSIONS

feature-based radiomics has an optimal potential to accurately predict response and radionecrosis after SRT of BM and facilitate differential diagnosis. Further validation studies are eagerly awaited to confirm radiomics reliability.

The role of radiation therapy and systemic therapies in elderly with breast cancer

The focus of this review deals with the management of elderly patients with early stage breast cancer, discussing the role of systemic therapies [endocrine therapy (ET), chemotherapy, novel agents] and radiation therapy (RT). Several studies have evaluated in elderly low risk patients the possibility of omitting the RT but, at the same time, higher locoregional relapse (LR) rates without significant impact on overall survival (OS) were observed in all studies when RT was excluded. Technological improvements [intensity-modulated RT (IMRT), volumetric modulated arc therapy (VMAT), high dose brachy therapy (HDBT)] are very useful in order to reduce cosmetic outcome and improve quality of life of frail patients. The optimal sequence of ET, concomitant or sequential to RT, is currently under investigation, and specifically in the elderly it is questioned the possible choice of prolonged therapy after standard 5 years. Data regarding chemotherapy suggesting no benefit of OS in endocrine responsive diseases, whereas endocrine non-responsive breast cancer still showed a better outcome. Cyclophosphamide, methotrexate and 5-fluorouracil (CMF) regimen is recognized as the standard protocol, although age-dependent increase in therapy related mortality was reported. Neoadjuvant chemotherapy in elderly showed a lower ratio of pathological complete response in comparison to younger patients, but triple negative breast cancer patients showed a good prognosis regarding OS, comparable to younger patients. The risk of cardiotoxicity seems to increase with age, so the use trastuzumab in this setting is much debated. Currently, other anti-HER2 agents (pertuzumab, lapatinib) are used in neoadjuvant setting, but the data on elderly are still premature. Novel molecules are rapidly changing the clinical management of breast cancer patients but are tested especially in locally advanced and metastatic setting. Among these, particularly interesting are inhibitors of CDK4 and 6, alpelisib (PI3K enzymes mutations), immune checkpoint (PD1, PDL1, CTLA4) inhibitors, atezolizumab. Elderly patients are under-represented in clinical trials, although ageing can be frequently correlated with a decrease in the effectiveness of the immune system. For elderly women, treatment decisions should be individually decided, taking into account the geriatric assessment and limited life expectancy and tumor characteristics.