Feasibility of tomotherapy to reduce normal lung and cardiac toxicity for distal esophageal cancer compared to three-dimensional radiotherapy

Novel simulation for dosimetry impact of diaphragm respiratory motion in four-dimensional volumetric modulated arc therapy for esophageal cancer

BACKGROUND AND PURPOSE

The diaphragm respiratory motion (RM) could impact the target dose robustness in the lower esophageal cancer (EC). We aimed to develop a framework evaluating the impact of different RM patterns quantitatively in one patient, by creating virtual four-dimensional computed-tomography (v4DCT) images, which could lead to tailored treatment for the breathing pattern. We validated virtual 4D radiotherapy (v4DRT) along with exploring the acceptability of free-breathing volumetric modulated arc therapy (FB-VMAT).

METHODS AND MATERIALS

We assessed 10 patients with superficial EC through their real 4DCT (r4DCT) scans. v4DCT images were derived from the end-inhalation computed tomography (CT) image (reference CT) and the v4DRT dose was accumulated dose over all phases. r4DRT diaphragm shifts were applied with magnitudes derived from r4DCT scans; clinical target volume (CTV) dose of v4DRT was compared with that of r4DRT to validate v4DRT. CTV dosage modifications and planning organ at risk volume (PRV) margins of the spinal cord were examined with the diaphragm movement. The percentage dose differences (ΔDx) were determined between the v4DRT and the dose calculated on the reference CT image.

RESULTS

The CTV ΔDx between the r4DRT and v4DRT were within 1% in cases with RM ≦ 15 mm. The average ΔD100% and ΔDmean of the CTV ranging from 5 to 15 mm of diaphragm motion was 0.3% to 1.7% and 0.1% to 0.4%, respectively. All CTV index changes were within 3% and ΔD1cc and ΔD2cc of Cord PRV were within 1%.

CONCLUSION

We postulate a novel method for evaluating the CTV robustness, comparable to the conventional r4DCT method under the diaphragm RM ≦ 15 mm permitting an impact of within 3% in FB-VMAT for EC on the CTV dose distribution.

Preparation and Evaluation of Animal Models of Cardiotoxicity in Antineoplastic Therapy

The continuous development of antineoplastic therapy has significantly reduced the mortality of patients with malignant tumors, but its induced cardiotoxicity has become the primary cause of long-term death in patients with malignant tumors. However, the pathogenesis of cardiotoxicity of antineoplastic therapy is currently unknown, and practical means of prevention and treatment are lacking in clinical practice. Therefore, how to effectively prevent and treat cardiotoxicity while treating tumors is a major challenge. Animal models are important tools for studying cardiotoxicity in antitumor therapy and are of great importance in elucidating pathophysiological mechanisms and developing and evaluating modality drugs. In this paper, we summarize the existing animal models in antitumor therapeutic cardiotoxicity studies and evaluate the models by observing the macroscopic signs, echocardiography, and pathological morphology of the animals, aiming to provide a reference for subsequent experimental development and clinical application.

Application of Radiomics for the Prediction of Radiation-Induced Toxicity in the IMRT Era: Current State-of-the-Art

Normal tissue complication probability (NTCP) models that were formulated in the Quantitative Analyses of Normal Tissue Effects in the Clinic (QUANTEC) are one of the pillars in support of everyday’s clinical radiation oncology. Because of steady therapeutic refinements and the availability of cutting-edge technical solutions, the ceiling of organs-at-risk-sparing has been reached for photon-based intensity modulated radiotherapy (IMRT). The possibility to capture heterogeneity of patients and tissues in the prediction of toxicity is still an unmet need in modern radiation therapy. Potentially, a major step towards a wider therapeutic index could be obtained from refined assessment of radiation-induced morbidity at an individual level. The rising integration of quantitative imaging and machine learning applications into radiation oncology workflow offers an unprecedented opportunity to further explore the biologic interplay underlying the normal tissue response to radiation. Based on these premises, in this review we focused on the current-state-of-the-art on the use of radiomics for the prediction of toxicity in the field of head and neck, lung, breast and prostate radiotherapy.

Contemporary Understandings of Cardiovascular Disease After Cancer Radiotherapy: a Focus on Ischemic Heart Disease

PURPOSE OF REVIEW

Radiation-induced cardiovascular disease, including coronary artery disease, is a well-known sequela of radiation therapy and represents a significant source of morbidity and mortality for cancer survivors. This review examines current literature and guidelines to care for this growing population of cancer survivors.

RECENT FINDINGS

The development of radiation-induced ischemic heart disease following radiation can lead even to early cardiotoxicities, inclusive of coronary artery disease, which limit cancer treatment outcomes. These coronary lesions tend to be diffuse, complex, and proximal. Early detection with multimodality imaging and targeted intervention is required to minimize these risks. Early awareness, detection, and management of radiation-induced cardiovascular disease are paramount as cancer survivorship continues to grow.

Effect of lung volume on helical radiotherapy in esophageal cancer: are there predictive factors to achieve acceptable lung doses?

PURPOSE

The dose received by the lungs in radiotherapy (RT) is affected by the patient's current lung volume. The presence of predictive factors and cut-off points were investigated to achieve acceptable lung doses in esophageal cancer (EC) treatment.

METHODS

Virtual RT volumes of supracarinal EC were delineated. RT plans were designed with standard criteria in the TomoTherapy planning system (TomoTherapy Inc., Madison, WI, USA). The total dose was 50.4 Gy (1.8 Gy/fraction). ROC (Receiver operating characteristic) analysis and Mann-Whitney U tests were performed.

RESULTS

There was a total of 65 patient plans included. ROC analysis showed that lung/PTV (Planning target volume) volume ratio (AUC [Area under curve]: 0.91, 95% CI: 0.83-0.99, p = 0.000) and bilateral lung volume (AUC: 0.81, 95% CI: 0.70-0.92, p = 0.000) have diagnostic power to predict the suitability of RT plans according to QUANTEC (Quantitative Analyses of Normal Tissue Effects in the Clinic) for lung dose constraints. The cut-off points of 7 and 3500 cc were selected for lung/PTV ratio and bilateral lung volume, respectively. The effect of the cut-off points on the dose data was assessed with the Mann-Whitney U test. The mean lung and heart doses, lung V5, V15, and V20, as well as heart V5, V20, V30, and V45 values were found to be lower in both groups separated by cut-off points (p < 0.05).

CONCLUSION

The lung/PTV ratio ≥7 and bilateral lung volume ≥3500 cc cut-off points are predictive of whether TomoTherapy plans may meet QUANTEC lung dose limits in patients with supracarinal esophageal cancer. The patients with lung/PTV ratio and lung volume above these cut-off points may be candidates for treatment with TomoTherapy.

Characterization of LAG-3, CTLA-4, and CD8+ TIL density and their joint influence on the prognosis of patients with esophageal squamous cell carcinoma

Background

We aimed to characterize the relationships of lymphocyte activation gene-3 (LAG-3) expression, cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) expression, and CD8⁺ tumor-infiltrating lymphocyte (TIL) density, and to investigate the joint prognostic impact of these three markers in patients with surgically resected esophageal squamous cell carcinoma (ESCC).

Methods

Expression of LAG-3, CTLA-4 and the density of CD8⁺ TILs were evaluated by immunohistochemistry in resected ESCC. The associations between LAG-3 expression and clinicopathologic characteristics, as well as patient prognoses, were analyzed.

Results

A total of 183 patients were included. LAG-3 expression was observed in 69 (37.7%) patients. Positive LAG-3 expression was significantly associated with CTLA-4 expression (P=0.004). LAG-3 positivity, CTLA-4 positivity, and low CD8⁺ TIL densities were significantly associated with worsening recurrence-free survival (RFS) [LAG-3: hazard ratio (HR), 1.72; 95% confidence interval (CI), 1.10-2.89; P=0.019; CTLA-4: HR, 1.69; 95% CI, 1.04-2.73; P=0.033; CD8⁺: HR, 0.60; 95% CI, 0.38-0.94; P=0.025] and overall survival (OS) (LAG-3: HR, 2.09; 95% CI, 1.24-3.53; P=0.006; CTLA-4: HR, 1.47; 95% CI, 0.86-2.53; P=0.161; CD8⁺: HR, 0.56; 95% CI, 0.33-0.95; P=0.032). Subgroup analysis revealed that the LAG-3 CTLA-4 CD8⁺ group had the best RFS (P<0.001) and OS (P<0.001).

Conclusions

LAG-3 expression was correlated with CTLA-4 expression on TILs. Positive LAG-3 expression was associated with poor prognoses in ESCC. A combination of LAG-3, CTLA-4 expression and CD8⁺ TILs density could further stratify patients into different subgroups with distinct prognoses.

Role of MAML1 in targeted therapy against the esophageal cancer stem cells

Background

Esophageal cancer is the sixth-leading cause of cancer-related deaths worldwide. Cancer stem cells (CSCs) are the main reason for tumor relapse in esophageal squamous cell carcinoma (ESCC). The NOTCH pathway is important in preservation of CSCs, therefore it is possible to target such cells by targeting MAML1 as the main component of the NOTCH transcription machinery.

Methods

In present study we isolated the CD44+ ESCC CSCs and designed a MAML1-targeted therapy to inhibit the NOTCH signaling pathway. CSCs were isolated using magnetic cell sorting utilizing the CD44 cell surface marker. Several stem cell markers were analyzed in the levels of protein and mRNA expression. The isolated CSCs were characterized in vivo in NUDE mice. Biological role of MAML1 was assessed in isolated CD44+ CSCs. A drug resistance assay was also performed to assess the role of MAML1 in CD44+ CSCs with 5FU resistance.

Results

The CD44+ CSCs had ability to form tumors in NUDE mice. MAML1 silencing caused a significant decrease (p = 0.019) and ectopic expression caused a significant increase in migration of CD44+ CSCs (p = 0.012). Moreover, MAML1 silencing and ectopic expression significantly increased and decreased 5FU resistance, respectively (p < 0.05). MAML1 silencing significantly increased the number of cells in G1 phase (p = 0.008), and its ectopic expression significantly increased the number of CD44+ CSCS in S phase (p = 0.037).

Conclusions

MAML1 may be utilized for targeted therapy with a low side effect to eliminate the CD44+ CSCs through inhibition of canonical NOTCH pathway in ESCC patients.

A rare rarity: Neuroendocrine tumor of the esophagus

Esophageal Neuroendocrine tumors (NETs) are rare, aggressive and lacking specific symptoms. This causes a diagnostic delay, worsening the prognosis. Numerous cases are reported in literature, without a consensus on the management. Our aim was to clarify epidemiology, clinical presentation, diagnostic, therapeutic management of esophageal NETs. Extensive literature search identified a total of 226 articles. One hundred twenty-five articles (n = 1676) met the inclusion criteria, showing that: the incidence of esophageal NET varies geographically; men (60-70 years) are more affected; smoking and alcohol abuse are the major risk factors; dysphagia, weight loss, appetite loss are the most common clinical features. The histotypes include high-grade small and large cell esophageal carcinomas and low-grade carcinoid tumors. Mixed neuroendocrine/non-neuroendocrine neoplasms are the most common. Often the diagnosis occurs randomly on endoscopic examination. Circulating markers, functional combined with conventional imaging contributes to the diagnosis and management. Treatment depends on type, grade and stage of the tumor.

Dosimetric comparison of TomoDirect, helical tomotherapy, VMAT, and ff-IMRT for upper thoracic esophageal carcinoma

BACKGROUND

The new TomoDirect (TD) modality offers a nonrotational option with discrete beam angles. We aim to compare dosimetric parameters of TD, helical tomotherapy (HT), volumetric-modulated arc therapy (VMAT), and fixed-field intensity-modulated radiotherapy (ff-IMRT) for upper thoracic esophageal carcinoma (EC).

METHODS

Twenty patients with cT2-4N0-1M0 upper thoracic esophageal squamous cell carcinoma (ESCC) were enrolled. Four plans were generated using the same dose objectives for each patient: TD, HT, VMAT with a single arc, and ff-IMRT with 5 fields (5F). The prescribed doses were used to deliver 50.4 Gy/28F to the planning target volume (PTV50.4) and then provided a 9 Gy/5F boost to PTV59.4. Dose-volume histogram (DVH) statistics, dose uniformity, and dose homogeneity were analyzed to compare treatment plans.

RESULTS

For PTV59.4, the D₂, D₉₈, D_mean, and V_100% values in HT were significantly lower than other plans (all p < 0.05), and those in TD were significantly lower than VMAT and ff-IMRT (all p < 0.05). However, there was no significant difference in the D₂ and D_mean values between VMAT and ff-IMRT techniques (p > 0.05). The homogeneity index (HI) differed significantly for the 4 techniques of TD, HT, VMAT, and ff-IMRT (0.03 ± 0.01, 0.02 ± 0.01, 0.06 ± 0.02, and 0.05 ± 0.01, respectively; p  < 0.001). The HI for TD was similar to HT (p = 0.166), and had statistically significant improvement compared to VMAT (p < 0.001) and ff-IMRT (p = 0.003). In comparison with the 4 conformity indices (CIs), there was no significant difference (p > 0.05). For PTV50.4, the D₂ and D_mean values in HT were significantly lower than other plans (all p < 0.05), and those in TD were significantly lower than VMAT and ff-IMRT (all p < 0.05). However, there was no significant difference in the D₂ and D_mean values between VMAT and ff-IMRT techniques (p > 0.05). No D₉₈ and V_100% parameters differed significantly among the 4 treatment types (p > 0.05). HT plans were provided for statistically significant improvement in HI (0.03 ± 0.01) compared to TD plans (0.05 ± 0.01, p = 0.003), VMAT (0.08 ± 0.03, p < 0.001), ff-IMRT (0.08 ± 0.01, p < 0.001). The HI revealed that TD was superior to VMAT and ff-IMRT (p < 0.05). The CI differed significantly for the 4 techniques of TD, HT, VMAT, and ff-IMRT (0.59 ± 0.10, 0.69 ± 0.11, 0.64 ± 0.09, and 0.64 ± 0.11, respectively; p = 0.035). The best CI was yielded by HT. We found no significant difference for the V₅, V₁₀, V₁₅, V₃₀, and the mean lung dose (MLD) among the 4 techniques (all p > 0.05). However, the V₂₀ differed significantly among TD, HT, VMAT, and ff-IMRT (21.50 ± 7.20%, 19.50 ± 5.55%, 17.65 ± 5.45%, and 16.35 ± 5.70%, respectively; p = 0.047). Average V₂₀ for the lungs was significantly improved by the TD plans compared to VMAT (p = 0.047), and ff-IMRT (p = 0.008). The V₅ value of the lung in TD was 49.30 ± 13.01%, lower than other plans, but there was no significant difference (p > 0.05). The D₁ of the spinal cord showed no significant difference among the 4 techniques (p = 0.056).

CONCLUSIONS

All techniques are able to provide a homogeneous and highly conformal dose distribution. The TD technique is a good option for treating upper thoracic EC involvement. It could achieve optimal low dose to the lungs and spinal cord with acceptable PTV coverage. HT is a good option as it could achieve quality dose conformality and uniformity, while TD generated superior conformality.

Definition of the margin of major coronary artery bifurcations during radiotherapy with electrocardiograph-gated 4D-CT

PURPOSE

The aim was to measure the cardiac motion-induced displacements of major coronary artery bifurcations utilizing electrocardiography (ECG)-gated four-dimensional computed tomography (4D-CT) and to determine the margin of coronary artery bifurcations.

METHODS

Thirty-seven female patients who underwent retrospective ECG-gated 4D-CT in inspiratory breath hold (IBH) were enrolled. The left main coronary artery bifurcation (LM), the obtuse marginal branch bifurcation (OM), the first diagonal branch bifurcation (D₁), the second diagonal branch bifurcation (D₂), the caudal portion of the left anterior descending branch (APX), the first right ventricular artery bifurcation (V) and the acute marginal branch bifurcation (AM) were contoured. The center of the contour of the coronary arterial bifurcations at end systole was defined as the standard, and the margin were then calculated.

RESULTS

The margin in the left-right (LR), cranio-caudal (CC), and anterior-posterior (AP) coordinates were as follows: LM 3, 3, and 3 mm; D₁ 6, 3, and 3 mm; D₂ 3, 3, and 3 mm; APX 4, 4, and 4 mm; OM 4, 6, and 5 mm; V 6, 8, and 7 mm; and AM 6, 8, and 7 mm, respectively.

CONCLUSION

Coronary artery bifurcations should be considered a separate organ at risk (OAR), and different margin should be provided due to the differences resulting from motion displacement. The maximum margin in the LR, CC, and AP coordinates of left coronary artery bifurcations were 6, 6, and 5 mm, and those of the right coronary artery bifurcations were 6, 8, and 7 mm, respectively.

Cytotoxic T lymphocyte antigen-4 expression in esophageal carcinoma: implications for prognosis

To examine the relationship between cytotoxic T lymphocyte antigen-4 (CTLA-4) expression and esophageal carcinoma prognosis, CTLA-4 expression was immunohistochemically detected in paraffin-embedded primary tumor specimens from 158 patients with esophageal cancer. CTLA-4 was detected in the cytoplasm and cell membranes of esophageal cancer cells and in interstitial lymphocytes. In univariate analyses (log-rank), higher interstitial CTLA-4⁺ lymphocyte density and higher tumor CTLA-4 expression were associated with shorter overall survival (OS). After controlling for age and clinical stage, multivariate analysis (Cox) found that tumor CTLA-4 expression was an independent predictor of shorter OS (HR 2.016, P = 0.004). These results indicate that CTLA-4 expression in the tumor environment (both lymphocytes and tumor cells) is associated with poorer prognosis. In addition, CTLA-4 profiles may be useful for predicting the benefits and toxicity of CTLA-4 blockade in patients with esophageal carcinoma.

Pathogenesis and Prevention of Radiation-induced Myocardial Fibrosis

Radiation therapy is one of the most important methods for the treatment of malignant tumors. However, in radiotherapy for thoracic tumors such as breast cancer, lung cancer, esophageal cancer, and mediastinal lymphoma, the heart, located in the mediastinum, is inevitably affected by the irradiation, leading to pericardial disease, myocardial fibrosis, coronary artery disease, valvular lesions, and cardiac conduction system injury, which are considered radiation-induced heart diseases. Delayed cardiac injury especially myocardial fibrosis is more prominent, and its incidence is as high as 20–80%. Myocardial fibrosis is the final stage of radiation-induced heart diseases, and it increases the stiffness of the myocardium and decreases myocardial systolic and diastolic function, resulting in myocardial electrical physiological disorder, arrhythmia, incomplete heart function, or even sudden death. This article reviews the pathogenesis and prevention of radiation-induced myocardial fibrosis for providing references for the prevention and treatment of radiation-induced myocardial fibrosis.

Current status of proteomics of esophageal carcinoma

INTRODUCTION

Esophageal cancer (EC) is one of the most common causes of cancer-related death worldwide. Identifying suitable biomarkers for early diagnosis as well as predicting lymph node metastasis, prognosis and the therapeutic response of EC is essential for the effective and efficient management for EC. There is an urgent need to develop effective, novel approaches for patients who do not respond to conventional treatment. Areas covered: EC is characterized by the presence of two main histological types such as squamous cell carcinoma and adenocarcinoma, which differ in their response to treatments and prognosis. Thus, this review describes the latest research into biomarkers and novel treatment targets generated by cancer proteomics for the two main histological types. Finally, the main difficulties facing the translation of biomarkers and novel treatment targets into the clinical settings are discussed. Expert commentary: EC proteomics have provided useful results and, after their validation, novel clinical tools should be developed to improve the clinical outcomes for EC patients.

[Radiotherapy Techniques and Radiation Pneumonitis: A Lot To A Little Or A Little To A Lot?]

放射治疗是肺癌的主要治疗手段之一，目前使用的主流技术是三维适形放疗（three-dimensional conformal radiation therapy, 3D-CRT）和调强适形放疗（intensity modulated radiation therapy, IMRT），两者各具特点。本文综述近年来两种放疗技术治疗肺癌的文献，重点讨论放射剂量在肺内的分布与放射性肺炎的关系，即高剂量分布在较小的肺体积与低剂量分布在较大的肺体积，两者哪种更易引发放射性肺炎（radiation pneumonitis, RP）。

Fan-shaped complete block on helical tomotherapy for esophageal cancer: a phantom study

Radiation pneumonitis (RP) is a common complication for radiotherapy of esophageal cancer and is associated with the low dose irradiated lung volume. This study aims to reduce the mean lung dose (MLD) and the relative lung volume at 20 Gy (V₂₀) and at low dose region using various designs of the fan-shaped complete block (FSCB) in helical tomotherapy. Hypothetical esophageal tumor was delineated on an anthropomorphic phantom. The FSCB was defined as the fan-shaped radiation restricted area located in both lungs. Seven treatment plans were performed with nonblock design and FSCB with different fan angles, that is, from 90° to 140°, with increment of 10°. The homogeneous index, conformation number, MLD, and the relative lung volume receiving more than 5, 10, 15, and 20 Gy (V₅, V₁₀, V₁₅, and V₂₀) were determined for each treatment scheme. There was a substantial reduction in the MLD, V₅, V₁₀, V₁₅, and V₂₀ when using different types of FSCB as compared to the nonblock design. The reduction of V₂₀, V₁₅, V₁₀, and V₅ was 6.3%–8.6%, 16%–23%, 42%–57%, and 42%–66% for FSCB 90°–140°, respectively. The use of FSCB in helical tomotherapy is a promising method to reduce the MLD, V₂₀, and relative lung volume in low dose region, especially in V₅ and V₁₀ for esophageal cancer.

Current advances in esophageal cancer proteomics

We review the current status of proteomics for esophageal cancer (EC) from a clinician's viewpoint. The ultimate goal of cancer proteomics is the improvement of clinical outcome. The proteome as a functional translation of the genome is a straightforward representation of genomic mechanisms that trigger carcinogenesis. Cancer proteomics has identified the mechanisms of carcinogenesis and tumor progression, detected biomarker candidates for early diagnosis, and provided novel therapeutic targets for personalized treatments. Our review focuses on three major topics in EC proteomics: diagnostics, treatment, and molecular mechanisms. We discuss the major histological differences between EC types, i.e., esophageal squamous cell carcinoma and adenocarcinoma, and evaluate the clinical significance of published proteomics studies, including promising diagnostic biomarkers and novel therapeutic targets, which should be further validated prior to launching clinical trials. Multi-disciplinary collaborations between basic scientists, clinicians, and pathologists should be established for inter-institutional validation. In conclusion, EC proteomics has provided significant results, which after thorough validation, should lead to the development of novel clinical tools and improvement of the clinical outcome for esophageal cancer patients. This article is part of a Special Issue entitled: Medical Proteomics.

Current status of predictive biomarkers for neoadjuvant therapy in esophageal cancer

Neoadjuvant therapy has been proven to be extremely valuable and is widely used for advanced esophageal cancer. However, a significant proportion of treated patients (60%-70%) does not respond well to neoadjuvant treatments and develop severe adverse effects. Therefore, predictive markers for individualization of multimodality treatments are urgently needed in esophageal cancer. Recently, molecular biomarkers that predict the response to neoadjuvant therapy have been explored in multimodal approaches in esophageal cancer and successful examples of biomarker identification have been reported. In this review, promising candidates for predictive molecular biomarkers developed by using multiple molecular approaches are reviewed. Moreover, treatment strategies based on the status of predicted biomarkers are discussed, while considering the international differences in the clinical background. However, in the absence of adequate treatment options related to the results of the biomarker test, the usefulness of these diagnostic tools is limited and new effective therapies for biomarker-identified nonresponders to cancer treatment should be concurrent with the progress of predictive technologies. Further improvement in the prognosis of esophageal cancer patients can be achieved through the introduction of novel therapeutic approaches in clinical practice.

Improved oncologic outcomes with image-guided intensity-modulated radiation therapy using helical tomotherapy in locally advanced hepatocellular carcinoma

AIM

To investigate whether image-guided intensity-modulated radiation therapy (IG-IMRT) improves survival in hepatocellular carcinoma (HCC) relative to 3-dimensional conformal radiotherapy (3D-CRT).

METHODS

Between 2006 and 2011, 187 HCC patients treated with definitive RT were reviewed. Median age was 53(range 51-83). All patients were stage III or IV-A. Concurrent chemoradiation was received by 178 patients (95.2 %). Overall actuarial survival (OS), progression-free survival (PFS), and infield-failure-free survival (IFFS) analyses were performed by Kaplan-Meier method. A Cox proportional hazards model was used for univariate and multivariate analysis. Pearson's chi-square test or Fisher's exact test was used to compare patient characteristics and treatment-related toxicity between the groups.

RESULTS

Sixty-five patients were treated with IG-IMRT and 122 patients with 3D-CRT. No significant differences were seen between the groups for all patient characteristics. IG-IMRT delivered higher doses than 3D-CRT (median biological effective dose 62.5 vs 53.1 Gy, P < 0.001). IG-IMRT showed significantly higher 3-year OS (33.4 vs 13.5 %, P < 0.001), PFS (11.1 vs 6.0 %, P = 0.004), and IFFS (46.8 vs 28.2 %, P = 0.007) than 3D-CRT. On univariate and multivariate analysis, RT modality was significant prognostic factor for OS (HR 2.18; 95 % CI 1.45-3.25; P < 0.001), PFS (HR 1.64; 95 % CI 1.17-2.29; P = 0.004). There was no significant difference between the two modalities for radiation-induced liver disease (P = 0.716).

CONCLUSION

Our findings suggest that IG-IMRT could be an effective treatment that provides survival benefit without increasing severe toxicity in locally advanced HCC.

Feasibility of intensity-modulated and image-guided radiotherapy for locally advanced esophageal cancer

BACKGROUND

In this study the feasibility of intensity-modulated radiotherapy (IMRT) and tomotherapy-based image-guided radiotherapy (IGRT) for locally advanced esophageal cancer was assessed.

METHODS

A retrospective study of ten patients with locally advanced esophageal cancer who underwent concurrent chemotherapy with IMRT (1) and IGRT (9) was conducted. The gross tumor volume was treated to a median dose of 70 Gy (62.4-75 Gy).

RESULTS

At a median follow-up of 14 months (1-39 months), three patients developed local failures, six patients developed distant metastases, and complications occurred in two patients (1 tracheoesophageal fistula, 1 esophageal stricture requiring repeated dilatations). No patients developed grade 3-4 pneumonitis or cardiac complications.

CONCLUSIONS

IMRT and IGRT may be effective for the treatment of locally advanced esophageal cancer with acceptable complications.

Cardiac complications after radical radiotherapy

Improvements in cancer therapy have led to increasing numbers of cancer survivors, and the long-term complications of these treatments are now becoming apparent. This article presents the current knowledge of adverse cardiovascular effects of radiotherapy to the chest. Medline literature searches relating to the cardiac complications of radiotherapy and subsequent prognosis were conducted. Potential adverse effects of mediastinal irradiation are numerous and can include coronary artery disease, pericarditis, cardiomyopathy, and valvular disease. Damage seems to be related to radiation dose, volume of irradiated heart, age at exposure, technique of chest irradiation, and patient-specific factors. The advent of technology and the newer sophisticated techniques in treatment planning and delivery are expected to decrease the incidence of cardiovascular diseases after radiation of the mediastinal structures. In any case, patients subjected to irradiation of the mediastinal structures require close multidisciplinary clinical monitoring.

Prediction of response to radiotherapy in the treatment of esophageal cancer using stem cell markers

BACKGROUND AND PURPOSE

In this study, we investigated whether cancer stem cell marker expressing cells can be identified that predict for the response of esophageal cancer (EC) to CRT.

MATERIALS AND METHODS

EC cell-lines OE-33 and OE-21 were used to assess in vitro, stem cell activity, proliferative capacity and radiation response. Xenograft tumors were generated using NOD/SCID mice to assess in vivo proliferative capacity and tumor hypoxia. Archival and fresh EC biopsy tissue was used to confirm our in vitro and in vivo results.

RESULTS

We showed that the CD44+/CD24- subpopulation of EC cells exerts a higher proliferation rate and sphere forming potential and is more radioresistant in vitro, when compared to unselected or CD44+/CD24+ cells. Moreover, CD44+/CD24- cells formed xenograft tumors faster and were often located in hypoxic tumor areas. In a study of archival pre-neoadjuvant CRT biopsy material from EC adenocarcinoma patients (N=27), this population could only be identified in 50% (9/18) of reduced-responders to neoadjuvant CRT, but never (0/9) in the complete responders (P=0.009).

CONCLUSION

These results warrant further investigation into the possible clinical benefit of CD44+/CD24- as a predictive marker in EC patients for the response to chemoradiation.

Critical structure sparing in stereotactic ablative radiotherapy for central lung lesions: helical tomotherapy vs. volumetric modulated arc therapy

Background

Helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) are both advanced techniques of delivering intensity-modulated radiotherapy (IMRT). Here, we conduct a study to compare HT and partial-arc VMAT in their ability to spare organs at risk (OARs) when stereotactic ablative radiotherapy (SABR) is delivered to treat centrally located early stage non-small-cell lung cancer or lung metastases.

Methods

12 patients with centrally located lung lesions were randomly chosen. HT, 2 & 8 arc (Smart Arc, Pinnacle v9.0) plans were generated to deliver 70 Gy in 10 fractions to the planning target volume (PTV). Target and OAR dose parameters were compared. Each technique’s ability to meet dose constraints was further investigated.

Results

HT and VMAT plans generated essentially equivalent PTV coverage and dose conformality indices, while a trend for improved dose homogeneity by increasing from 2 to 8 arcs was observed with VMAT. Increasing the number of arcs with VMAT also led to some improvement in OAR sparing. After normalizing to OAR dose constraints, HT was found to be superior to 2 or 8-arc VMAT for optimal OAR sparing (meeting all the dose constraints) (p = 0.0004). All dose constraints were met in HT plans. Increasing from 2 to 8 arcs could not help achieve optimal OAR sparing for 4 patients. 2/4 of them had 3 immediately adjacent structures.

Conclusion

HT appears to be superior to VMAT in OAR sparing mainly in cases which require conformal dose avoidance of multiple immediately adjacent OARs. For such cases, increasing the number of arcs in VMAT cannot significantly improve OAR sparing.

Radiation Therapy and Esophageal Cancer

Background

Squamous cell carcinoma and adenocarcinoma account for more than 90% of all esophageal cancer cases. Although the incidence of squamous cell carcinoma has declined, the incidence of adenocarcinoma has risen due to increases in obesity and gastroesophageal reflux disease.

Methods

The authors examine the role of radiation therapy alone (external beam and brachytherapy) for the management of esophageal cancer or combined with other modalities. The impact on staging and appropriate stratification of patients referred for curative vs palliative intent with modalities is reviewed. The authors also explore the role of emerging radiation technologies.

Results

Current data show that neoadjuvant chemoradiotherapy followed by surgical resection is the accepted standard of care, with 3-year overall survival rates ranging from 30% to 60%. The benefit of adjuvant radiation therapy is limited to patients with node-positive cancer. The survival benefit of surgical resection after chemoradiotherapy remains controversial. External beam radiation therapy alone results in few long-term survivors and is considered palliative at best. Radiation dose-escalation has failed to improve local control or survival. Brachytherapy can provide better long-term palliation of dysphagia than metal stent placement. Although three-dimensional conformal treatment planning is the accepted standard, the roles of IMRT and proton therapy are evolving and potentially reduce adverse events due to better sparing of normal tissue.

Conclusions

Future directions will evaluate the benefit of induction chemotherapy followed by chemoradiotherapy, the role of surgery in locally advanced disease, and the identification of responders prior to treatment based on microarray analysis.

Multidisciplinary management of esophageal cancer

This article reviews the current management of esophageal cancer, including staging and treatment options, as well as providing support for using multidisciplinary teams to better manage esophageal cancer patients.