Effects of gait intervention using the draw-in maneuver on knee joint function and the thoracic kyphosis angle in knee osteoarthritis

BACKGROUND

To evaluate whether the knee adduction moment (KAM) could be reduced by a short instruction in the Draw-in (DI) maneuver in healthy adults, and whether knee joint function would improve with a longer DI gait intervention in patients with knee osteoarthritis (OA).

METHOD

In Study 1, healthy adults received 10 minutes supervised instruction in DI gait in and then practiced the gait independently for 10 minutes. Three-dimensional motion analysis measurement was performed in each phase. In Study 2, patients with OA performed a 20-minute DI gait intervention daily for 6 weeks. At baseline and after 6 weeks, knee pain, the Knee injury and Osteoarthritis Outcome Score, the MOS 8 item Short-Form Health Survey, thoracic kyphosis angle, knee joint range of motion, knee extension muscle strength, hip abduction muscle strength, and activity level were evaluated.

RESULTS

In Study 1, the DI gait to decrease KAM could be learning following only 10 minutes of instruction and 10 minutes of self-practice in healthy adults. In Study 2, knee pain was reduced by 19 % and the thoracic kyphosis angle was reduced by 2.6° after 6 weeks. No significant changes in other parameters were detected, and the implementation rate was 86 ± 14 %.

SIGNIFICANCE

In healthy adults, DI gait instruction for 10 minutes of instruction and 10 minutes of self-practice reduced the KAM. In patients with knee OA, 20 minutes of DI gait per day for 6 weeks may reduce knee pain and thoracic kyphosis.

Postoperative Lymph Node Recurrence in Esophageal Cancer After Surgery and Prognosis of Chemoradiotherapy

Background/Aim

This study aimed to evaluate the long-term prognosis of definitive chemoradiotherapy and clinical features of postoperative lymph node (LN) recurrence after curative resection of thoracic esophageal squamous cell cancer (ESCC).

Patients and Methods

A total of 586 patients who underwent radical resection of ESCC at the Hiroshima University Hospital from January 2000 to December 2019 were reviewed retrospectively. This study analyzed the clinical characteristics of 54 patients who developed recurrence in a solitary LN by comparing them to 182 patients who experienced total recurrence. Additionally, we analyzed the prognostic factors of 50 patients who received chemo-radiotherapy (CRT).

Results

The results revealed a tendency for a higher incidence of solitary LN recurrence in cases of early esophageal cancer and upper thoracic esophageal cancer among all recurrence cases. The 3-, 5-, and 7-year overall survival (OS) rates were 40.5%, 37.8% and 34.6%, respectively, with a median survival time of 27.9 months. Univariate analysis of OS factors, such as age, depth of the primary tumor at the initial surgery, time to LN recurrence after surgery, site of LN recurrence, and the number of the regional LNs with recurrence showed no significant impact on OS.

Conclusion

Approximately 35% of patients with ESCC who experienced LN recurrence after curative resection achieved long-term survival through CRT. Despite the absence of identifiable prognostic factors, CRT proves to be a valuable initial treatment option for LN recurrence.

Radiation doses of medical radiation workers performing low-dose-rate brachytherapy with 198Au grains and 192Ir pins for patients with oral cancers

OBJECTIVES

Low-dose-rate brachytherapy (LDR-BT) with 198Au grains and 192Ir pins is an essential treatment option for oral cancer due to its high rate of local control and low invasiveness. However, the radiation exposure of medical radiation workers is concerning. Thus, we aimed to determine the radiation dose delivered to medical radiation workers during LDR-BT using 198Au grains and 192Ir pins for oral cancer.

METHODS

Thirty-two patients with oral cancer underwent 198Au grain interstitial LDR-BT between June 2016 and May 2023, and 23 patients with tongue cancer underwent 192Ir pin interstitial LDR-BT between March 2015 and November 2017 at our hospital. Dosimetry was performed by attaching a dosimeter to the chest pocket of the operator and assistant during 198Au grain or 192Ir pin LDR-BT. Since the operator also loads 198Au grains into the implantation device, the operator's radiation dose includes the dose received during this preparation.

RESULTS

Mean radiation doses of the operators with 198Au grain and 192Ir pin LDR-BT were 165.8 and 211.2 μSv, respectively. Statistically significant differences between the radioactive sources of 198Au grain and 192Ir pin LDR-BT were observed (p = 0.0459). The mean radiation doses of the assistants with 198Au grain and 192Ir pin LDR-BT were 92.0 and 162.0 μSv, respectively. Statistically significant differences were observed between the radioactive sources of 198Au grains and 192Ir pin LDR-BT (p = 0.0003).

CONCLUSIONS

Regarding radioactive source differences, 192Ir pin LDR-BT resulted in higher doses delivered to medical radiation workers than 198Au grain LDR-BT.

Prognostic factors for esophageal squamous cell carcinoma without pathological lymph node metastasis after neoadjuvant therapy and surgery

BACKGROUND

Pathological lymph node metastasis (LNM) following multimodal therapy is an important indicator of poor prognosis in patients with esophageal cancer. However, a significant number of patients without LNM are still at high risk for recurrence.

METHODS

We assessed prognostic factors in 143 patients without pathological LNM who were diagnosed with locally advanced esophageal squamous cell carcinoma (ESCC) and underwent neoadjuvant chemotherapy (NAC) or chemoradiotherapy (NACRT), followed by surgery.

RESULTS

Using univariate and multivariate analyses of recurrence-free survival, carcinoembryonic antigen (CEA) levels (hazard ratio [HR]: 2.17, 95% confidence interval [CI]: 1.12-4.23, and p = 0.02) and neutrophil-to-lymphocyte ratio (NLR) (HR: 1.22, 95% CI: 1.04-1.43, and p = 0.02) were significant independent covariates. Furthermore, pretherapeutic LNM (HR: 1.94, 95% CI: 1.003-3.76, and p = 0.049), NACRT (HR: 3.29, 95% CI: 1.30-8.33, and p = 0.01), poorly differentiated tumors (HR: 2.52, 95% CI: 1.28-4.98, and p = 0.01), and lymphovascular invasion (LVI) (HR: 2.78, 95% CI: 1.27-6.09, and p = 0.01) were also significant independent covariates. The recurrence rates among patients with 0/1, 2, 3, and 4/5 poor prognostic factors were significantly different (5.0%, 25.0%, 35.7%, and 53.8%, respectively; p = 0.001); the survival rates were stratified among these prognostic groups.

CONCLUSIONS

Pretherapeutic CEA and NLR levels, pretherapeutic LNM, NACRT, poorly differentiated tumors, and LVI were significantly correlated with survivals in patients without pathological LNM after neoadjuvant therapy and surgery. Postoperative therapy should be considered in patients with ESCC with several indicators of recurrence, even in those without pathological LNM who underwent surgery following neoadjuvant therapy.

Radiomics and dosiomics for predicting complete response to definitive chemoradiotherapy patients with oesophageal squamous cell cancer using the hybrid institution model

OBJECTIVES

To develop a multi-institutional prediction model to estimate the local response to oesophageal squamous cell carcinoma (ESCC) treated with definitive radiotherapy based on radiomics and dosiomics features.

METHODS

The local responses were categorised into two groups (incomplete and complete). An external validation model and a hybrid model that the patients from two institutions were mixed randomly were proposed. The ESCC patients at stages I-IV who underwent chemoradiotherapy from 2012 to 2017 and had follow-up duration of more than 5 years were included. The patients who received palliative or pre-operable radiotherapy and had no FDG PET images were excluded. The segmentations included the GTV, CTV, and PTV which are used in treatment planning. In addition, shrinkage, expansion, and shell regions were created. Radiomic and dosiomic features were extracted from CT, FDG PET images, and dose distribution. Machine learning-based prediction models were developed using decision tree, support vector machine, k-nearest neighbour (kNN) algorithm, and neural network (NN) classifiers.

RESULTS

A total of 116 and 26 patients enrolled at Centre 1 and Centre 2, respectively. The external validation model exhibited the highest accuracy with 65.4% for CT-based radiomics, 77.9% for PET-based radiomics, and 72.1% for dosiomics based on the NN classifiers. The hybrid model exhibited the highest accuracy of 84.4% for CT-based radiomics based on the kNN classifier, 86.0% for PET-based radiomics, and 79.0% for dosiomics based on the NN classifiers.

CONCLUSION

The proposed hybrid model exhibited promising predictive performance for the local response to definitive radiotherapy in ESCC patients.

CLINICAL RELEVANCE STATEMENT

The prediction of the complete response for oesophageal cancer patients may contribute to improving overall survival. The hybrid model has the potential to improve prediction performance than the external validation model that was conventionally proposed.

KEY POINTS

• Radiomics and dosiomics used to predict response in patients with oesophageal cancer receiving definitive radiotherapy. • Hybrid model with neural network classifier of PET-based radiomics improved prediction accuracy by 8.1%. • The hybrid model has the potential to improve prediction performance.

Dosiomics for intensity-modulated radiotherapy in patients with prostate cancer: survival analysis stratified by baseline prostate-specific antigen and Gleason grade group in a 2-institutional retrospective study

OBJECTIVE

This study evaluated the prognostic impact of the quality of dose distribution using dosiomics in patients with prostate cancer, stratified by pretreatment prostate-specific antigen (PSA) levels and Gleason grade (GG) group.

METHODS

A total of 721 patients (Japanese Foundation for Cancer Research [JFCR] cohort: N = 489 and Tokyo Radiation Oncology Clinic [TROC] cohort: N = 232) with localized prostate cancer treated by intensity-modulated radiation therapy were enrolled. Two predictive dosiomic features for biochemical recurrence (BCR) were selected and patients were divided into certain groups stratified by pretreatment PSA levels and GG. Freedom from biochemical failure (FFBF) was estimated using the Kaplan-Meier method based on each dosiomic feature and univariate discrimination was evaluated using the log-rank test. As an exploratory analysis, a dosiomics hazard (DH) score was developed and its prognostic power for BCR was examined.

RESULTS

The dosiomic feature extracted from planning target volume (PTV) significantly distinguished the high- and low-risk groups in patients with PSA levels >10 ng/mL (7-year FFBF: 86.7% vs 76.1%, P < .01), GG 4 (92.2% vs 76.9%, P < .01), and GG 5 (83.1% vs 77.8%, P = .04). The DH score showed significant association with BCR (hazard score: 2.04; 95% confidence interval: 1.38-3.01; P < .001).

CONCLUSION

The quality of planned dose distribution on PTV may affect the prognosis of patients with poor prognostic factors, such as PSA levels >10 ng/mL and higher GGs.

ADVANCES IN KNOWLEDGE

The effects of planned dose distribution on prognosis differ depending on the patient's clinical background.

Unbiased evaluation of predicted gamma passing rate by an event-mixing technique

BACKGROUND

Predicting models of the gamma passing rate (GPR) have been studied to substitute the measurement-based gamma analysis. Since these studies used data from different radiotherapy systems comprising TPS, linear accelerator, and detector array, it has been difficult to compare the performances of the predicting models among institutions with different radiotherapy systems.

PURPOSE

We aimed to develop unbiased scoring methods to evaluate the performance of the models predicting the GPR, by introducing both best and worst limits for the performance of the GPR prediction.

METHODS

Two hundred head-and-neck VMAT plans were used to develop a framework. The GPRs were measured using the ArcCHECK device. The predicted GPR [p] was generated using a deep learning-based model [pDL ]. The predicting model was evaluated using four metrics: standard deviation (SD) [σ], Pearson's correlation coefficient (CC) [r], mean squared error (MSE) [s], and mean absolute error (MAE) [a]. The best limit [σ m ${\sigma _m}$ ,r m ${r_m}$ ,s m ${s_m}$ , anda m ${a_m}$ ] was estimated by measuring the SD of measured GPR [m] by shifting the device along the longitudinal direction to measure different sampling points. Mimicked best and worst p's [pbest and pworst ] were generated from pDL . The worst limit was defined such that m and p have no correlation [CC ∼ 0]. The worst limit [σMix , rMix , sMix , and aMix ] was generated using the event-mixing (EM) technique originally introduced in high-energy physics experiments. The range of σ, r, s, and a was defined to be[ σ m , σ Mix ] $[ {{\sigma _m},{\sigma _{{\mathrm{Mix}}}}} ]$ ,[ 0 , r m ] $[ {0,{r_m}} ]$ ,[ s m , s Mix ] $[ {{s_m},{s_{{\mathrm{Mix}}}}} ]$ , and[ a m , a Mix ] $[ {{a_m},{a_{{\mathrm{Mix}}}}} ]$ . The achievement score (AS) independently based on σ, r, s, and a were calculated for pDL , pbest and pworst . The probability that p fails the gamma analysis (alert frequency; AF) was estimated as a function ofσ d ${\sigma _d}$ values within the [σ m ${\sigma _m}$ , σMix ] range for the 3%/2 mm data with a 95% criterion.

RESULTS

SDs of the best limit were well reproduced byσ m = 0.531 100 - m ${\sigma _m} = \;0.531\sqrt {100 - m} $ . The EM technique successfully generated the( m , p ) $( {m,p} )$ pairs with no correlation. The AS using four metrics showed good agreement. This agreement indicates successful definitions of both best and worst limits, consistent definitions of the AS, and successful generations of mixed events. The AF for the DL-based model with the 3%/2 mm tolerance was 31.5% and 63.0% with CL's 99% and 99.9%, respectively.

CONCLUSION

We developed the AS to evaluate the predicting model of the GPR in an unbiased manner by excluding the effects of the precision of the radiotherapy system and the spreading of the GPR. The best and worst limits of the GPR prediction were successfully generated using the measured precision of the GPR and the EM technique, respectively. The AS andσ p ${\sigma _p}$ are expected to enable objective evaluation of the predicting model and setting exact achievement goal of precision for the predicted GPR.

Risk factors for aortoesophageal fistula in cT4b esophageal squamous cell carcinoma after definitive radiation therapy

Background

Esophageal fistula (EF) is a serious complication in patients with cT4b esophageal squamous cell carcinoma (ESCC) with adjacent organ involvement. Among EFs, aortoesophageal fistula (AEF), forming a fistula with the aorta, could be fatal. This study aimed to identify the risk factors for AEF in patients with cT4b ESCC with obvious or suspected aortic invasion who underwent definitive radiotherapy (DRT).

Methods

Forty-four patients with cT4b ESCC with obvious or suspected invasion to the aorta who underwent DRT were included. Blood tests and computed tomography (CT) findings before and after DRT were compared between the patients with and without AEF to identify the potential risk factors for AEF.

Results

Nine patients (20.5%) developed AEF after DRT. Comparing between patients with and without AEF, pre-DRT white blood cell counts and post-DRT C-reactive protein (CRP) levels were significantly higher in patients with AEF. Furthermore, pre-DRT CT findings were similar between the two groups. However, post-DRT CT findings demonstrated significantly larger picus angle and lower esophageal wall thickness on the aortic side in patients with AEF. Multivariate analysis identified elevated post-DRT CRP levels [<3.3 versus ≥3.3 mg/dL; odds ratio (OR): 30.7; 95% confidence interval (CI): 2.92-323.2; P=0.004] and esophageal wall thinning on post-DRT CT scans (>6 versus ≤6 mm; OR: 13.2; 95% CI: 1.24-140.1; P=0.033) as risk factors for AEF.

Conclusions

We found that post-DRT esophageal wall thinning on the aortic side, as observed on CT scans, and elevated CRP levels were predictive factors for AEF in patients with cT4b ESCC with obvious or suspected invasion to the aorta.

A Nomogram Based on Pretreatment Radiomics and Dosiomics Features for Predicting Overall Survival for Esophageal Squamous Cell Cancer: Multi-Institutional Study

PURPOSE/OBJECTIVE(S)

The current study aims to propose a nomogram-based 2- and 3-years survival prediction model for esophageal squamous cell carcinoma treated by definitive radiotherapy using pretreatment computed tomography (CT), positron emission tomography (FDG PET) radiomic features and dosiomics features in addition to the common clinical factors using multi-institution data.

MATERIALS/METHODS

Data of 112 patients from one institution and 28 patients from the other institution were retrospectively collected. Radiomics and dosiomics features were extracted using five segmentations on CT and PET images and dose distribution. The least absolute shrinkage and selection operator (LASSO) with logistic regression was used to select radiomics and dosiomics features by calculating the radiomics and dosiomics scores (Rad-score and Dos-score), respectively, in the training model. The predictive clinical factors, Rad-score, and Dos-score were identified to develop a nomogram model.

RESULTS

We extracted 15219 features from the radiomics and dosiomics analysis. By LASSO Cox regression analysis, 13 CT-based radiomics features, 11 PET-based radiomics features, and 19 dosiomics features were selected. Clinical factors of T-stage, N-stage, and clinical stage were selected as significant prognostic factors by univariate Cox regression analysis. A predictive nomogram for prognosis in was established using these factors. In the external validation cohort, the C-index of the combined model of CT-based radiomics, PET-based radiomics, and dosiomics features with clinical factors were 0.74, 0.82, and 0.92, respectively. Moreover, we divided the cohort into high-risk and low-risk groups using the median nomogram score. Significant differences in overall survival (OS) in the combine model of CT-based radiomics, PET-based radiomics, and dosiomics features with clinical factors were observed between the high-risk and low-risk groups (P = 0.019, P = 0.038, and 0.014, respectively).

CONCLUSION

The current study established and validated 2- and 3-year survival prediction models based on radiomics and dosiomics features with clinical factors. The prediction model with dosiomics analysis could better predict OS than CT- and PET-based radiomics analysis in esophageal cancer patients treated with 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.

Laryngo-Esophageal Dysfunction Free Survival of Chemoradiation for Cervical Esophageal Cancer

PURPOSE/OBJECTIVE(S)

Chemoradiotherapy is often the treatment of choice for cervical esophageal cancer due to the invasiveness of surgery. However, toxicity after chemoradiotherapy often affects the quality of life related to swallowing and speech. This study evaluated laryngoesophageal dysfunction-free survival (LEDFS) in patients with cervical esophageal cancer, which has recently been used in head and neck cancer.

MATERIALS/METHODS

We analyzed 59 patients with cervical esophageal cancer without distant metastases other than supraclavicular lymph node metastases who received radical chemoradiotherapy with 5-fluorouracilplus platinum between 2002 and 2018. Loco-regional control (LRC), overall survival (OS), LEDFS, metachronous esophageal cancer incidence rates, and late toxicities were evaluated. LEDFS events were defined as death, local recurrence, total or partial laryngectomy, tracheostomy for more than 2 years, and feeding tube use for more than 2 years, as recommended by the Larynx Preservation Consensus Panel. The Kaplan-Meier method was used to calculate survival rates. The generalized Wilcoxon test was used to compare the two groups. The Common Terminology Criteria for Adverse Events v5.0 was used to assess toxicities.

RESULTS

The median age was 66 years (range, 38-83). There were 13 women and 46 men. Stage I, II, III, IVA, and IVB disease according to UICC 8th staging were 15, 9, 9, 10, and 16 patients, respectively. 22 received conventional radiotherapy and 37 received volumetric modulated arc therapy. The median total irradiation dose was 66 Gy. Platinum plus 5-fluorouracil chemotherapy was administered to all patients. The median follow-up for survivors was 87.5 months. The 5-year LRC, OS, and LEDFS rates were 54.2%, 48.9%, and 41.9%, respectively. The prognostic factors for OS were performance status (PS), hypopharyngeal extension, and clinical stage in univariate analysis and only clinical stage (hazard ratio [HR] 3.87, 95% Confidence interval [CI]: 1.52-9.87, p<0.01) in multivariate analysis; the prognostic factors for LEDFS were PS, hypopharyngeal extension and clinical stage in univariate analysis and hypopharyngeal extension (HR 2.38, 95% CI: 1.12-5.03, p = 0.02) and clinical stage (HR 4.07, 95% CI: 1.48-11.06, p<0.02) in multivariate analysis. Metachronous esophageal cancer was observed in 28.6% of patients at 5 years. As severe late toxicities, grade 3 pneumonitis, esophageal stricture, esophageal fistula, laryngeal stricture, and laryngeal edema were observed in 1 (2%), 1 (2%) and 4 (7%), 1 (2%) and 1 (2%), respectively. Grade 2 hypothyroidism was observed in 31 (53%) patients.

CONCLUSION

Chemoradiation for cervical esophageal cancer showed good results. The prognostic factors for LEDFS were pharyngeal extension and clinical stage. Late esophageal and laryngeal toxicity, hypothyroidism, and metachronous esophageal cancer should be noted.

Impact of the G8 Score on Treatment Strategies and Outcome in Definitive Radiotherapy for the Elderly Esophageal Cancer Patients

PURPOSE/OBJECTIVE(S)

Although chemoradiotherapy (CRT) is widely used as a curative treatment for esophageal cancer, it is often difficult to perform standard CRT for the elderly in the real world. This study aimed to investigate the impact of the Geriatric 8 (G8) score on treatment strategies and outcome in definitive radiotherapy (RT) for elderly esophageal cancer patients.

MATERIALS/METHODS

We analyzed 81 esophageal cancer patients aged ≥65 years who received definitive RT between 2018 and 2021. The G8 score was acquired at the first visit to the radiation oncology department. The treatment strategy was decided by a multi-disciplinary conference, and the G8 score was not used to determine the treatment strategy. Standard treatment (standard CRT) was defined as RT with elective nodal irradiation and a total dose ≥50 Gy, and chemotherapy with two cycles of platinum (70 mg/m2) and 5FU (700 mg/m2 for 4 days) concurrently. The Kaplan-Meier method was used to generate actual survival curves. The Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 was used to assess toxicities. The Mann-Whitney U test was used to compare the two groups, and statistical significance was set at p<0.05. The Receiver Operating Characteristic (ROC) curve was used to calculate the cutoff value.

RESULTS

The Median follow-up time was 30 months (range: 8-51) for survivors. The mean G8 scores by treatment strategy were 13.9 (range: 9-17) for standard CRT group (n = 26), 12.1 (range: 7-16) for reduced CRT group (n = 30), and 9.7 (range: 4.5-14) for RT alone group (n = 25). G8 score was significantly higher for standard CRT (p = 0.017) and significantly lower for RT alone (p<0.01). The cut-off value of the G8 score for standard treatment, calculated by the ROC curve, was 12.5 points. In the non-standard treatment group, the cut-off value of the G8 score for RT alone, calculated by the ROC curve, was 10.5 points. The 2-year overall survival (OS) rates for standard CRT, reduced CRT and RT alone were 74%, 71% and 35%, respectively, and significantly lower in RT alone (p<0.001). The 2-years OS rates for G8 score >10.5 points and ≤10.5 points were 69% and 48%, respectively (p = 0.039). Grade 3 or higher acute toxicities were observed in 33 patients (41%); 14 (54%) in standard CRT, 17 (57%) in reduced CRT and 2 (8%) in RT alone. Grade 5 acute toxicity was not observed. G8 scores tended to be higher in the patients with grade 3 or higher acute toxicities, but the difference was not statistically significant (p = 0.057). Grade 3 or higher late toxicities were observed in 7 patients.

CONCLUSION

Our results suggest that there is an association between the G8 score and clinicians' treatment decisions. Although RT alone could be safely performed even in patients with low G8 scores, administration of chemotherapy strongly affected prognosis. These results suggest the importance of developing less toxic systemic therapy regimens for patients with low G8 scores.

Predictive Modeling of Radiation Pneumonitis Induced by Chemoradiotherapy for Locally Advanced Non-Small Cell Lung Cancer Using Radiomics and Clinical Features

PURPOSE/OBJECTIVE(S)

The purpose of this study is to establish a prediction model for the development of grade 2 or higher radiation pneumonitis (RP) using radiomics analysis of pretreatment CT images, PET images, and dose distribution, in addition to clinical factors, in patients with locally advanced non-small cell lung cancer (NSCLC) treated with radical chemoradiotherapy.

MATERIALS/METHODS

We retrospectively evaluated 128 cases of locally advanced NSCLC treated with radical radiotherapy at our institution from 2008 to 2021. Clinical factors included age, sex, performance status (PS), KL-6, smoking history, histological type, clinical stage, and total radiation dose. Radiomics analysis was performed by analyzing treatment planning CT images, PET images, and dose distribution, and Rad-score (Radiomics-score) was calculated for the extracted features using Lasso-Cox regression. Rad-score (Radiomics-score) was calculated by Lasso-Cox regression for the extracted features. Risk factors were selected by univariate/multivariate analysis of clinical factors and Rad-score. Three models for predicting RP were developed from the identified risk factors using Nomogram: Clinical, Rad-score, and Combined model. The model was evaluated using area under the curve (AUC) based on receiver operating characteristic (ROC) curves and concordance index (C-index). RP was evaluated using the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. The cumulative incidence of Grade 2 or higher RP was evaluated using the Kaplan-Meier method.

RESULTS

Of the 128 cases, grade 2 or higher RP was observed in 50 cases (39%). Regarding clinical factors, gender, smoking status, and histology were selected as significant predictors of RP. Lasso-Cox analysis of radiomics features selected 11 features from CT images, 7 features from PET images, and 16 features from dose distribution as predictors of RP, yielding a total of 34 factors. The combined model (C-index: 0.96, AUC: 0.92) showed the best discrimination performance compared to the clinical model (C-index: 0.73, AUC: 0.56) and the Rad-score model (C-index: 0.87, AUC: 0.92). Risk classification using the combined model showed that the 1-year cumulative incidence of grade 2 or higher RP was 65% in the high-risk group, significantly higher than 15% in the low-risk group (p<0.001).

CONCLUSION

The combined model with Rad-score and clinical factors can predict grade 2 or higher RP in NSCLC patients with high accuracy.

Efficacy of Supportive Care for Radiodermatitis in Patients with Head and Neck Cancer: Supplementary Analysis of an Exploratory Phase II Trial

Self-care demonstrated efficacy in preventing severe acute radiation dermatitis among patients with head and neck squamous cell carcinoma undergoing chemoradiotherapy (CRT). This prospective trial aimed to confirm the feasibility and safety of transcutaneous electrical sensory stimulation while examining the relationship between changes in self-care behavior through supportive care interventions and the severity of acute radiation dermatitis during CRT. Patients underwent assessments for dermatitis grading (Grades 1 to ≥3) and were interviewed regarding self-care practices. The self-care questionnaires comprised six items, and a point was deducted for each task that the patient could not perform independently. Statistical analysis was performed to determine the association between G3 radiation dermatitis and the lowest self-care behavior scores. Of the 10 patients enrolled, three experienced G3 dermatitis. During CRT, six patients maintained their initial scores and did not develop ≥G3 dermatitis. Meanwhile, three of four patients with decreased scores exhibited ≥G3 dermatitis. The group with ≥G3 dermatitis had significantly lower scores than those with ≤G2 dermatitis, suggesting that the inability of patients to perform self-care routinely may lead to severe acute radiation dermatitis. Further prospective studies are needed to confirm the potential of self-care interventions in preventing severe dermatitis.

Outcome of Hypofractionated Radiotherapy for Localized Gastric Mucosa-associated Lymphoid Tissue Lymphoma

BACKGROUND/AIM

With the prevalence of COVID-19, the importance of short-course radiotherapy (RT) in many cancers has been discussed. The aim of this study was to evaluate the results of hypofractionated schedule RT for localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma.

PATIENTS AND METHODS

We assessed 45 patients with localized gastric MALT lymphoma who underwent RT between 2005 and 2019. The total RT dose ranged from 24-36 Gy in 10-18 fractions (median of 28 Gy/14 fractions). Patients were divided into three groups according to the dose fractionation: Group A, 30-36 Gy in 15-18 fractions; Group B, 26-28 Gy in 13-14 fractions; and Group C, 24-25 Gy in 10 fractions.

RESULTS

All the patients achieved complete remission without local recurrence. The 5-year overall, cause-specific, and progression-free survival rates were 97.5%, 100%, and 97.5%, respectively, with a median follow-up period of 82 months. Among the dose fractionation groups, there were no statistically significant differences in local control or incidence of grade 2 or worse adverse events.

CONCLUSION

Results of RT for localized gastric MALT lymphoma showed excellent local control and survival with no serious adverse events, regardless of dose fractionation. In situations where short-term RT is required, a hypofractionated RT schedule of 24-25 Gy in 10 fractions could be an option for RT schedules.

Effectiveness of Spacers in Brachytherapy With 198Au Grains for Patients With Buccal Mucosa Cancer

BACKGROUND/AIM

The aim of this study was to investigate the use of spacers and their efficacy in brachytherapy with ¹⁹⁸Au grains for buccal mucosa cancer.

PATIENTS AND METHODS

Sixteen patients with squamous cell carcinoma of the buccal mucosa who were treated with ¹⁹⁸Au grain brachytherapy were included. The distance between ¹⁹⁸Au grains, distance between ¹⁹⁸Au grains and the maxilla or mandible, and the maximum dose/cc to the jawbone (D1cc) with and without a spacer was investigated in three out of 16 patients.

RESULTS

The median distance between ¹⁹⁸Au grains without and with a spacer was 7.4 and 10.7 mm, respectively; this was significantly different. The median distance between ¹⁹⁸Au grains and the maxilla without and with a spacer was 10.3 and 18.5 mm, respectively; again this was significantly different. The median distance between ¹⁹⁸Au grains and the mandible without and with a spacer was 8.6 and 17.3 mm, respectively; the difference was significant. The D1cc to the maxilla without and with a spacer were 14.9, 68.7, and 51.8 Gy and 7.5, 21.2, and 40.7 Gy in cases 1, 2, and 3, respectively. The D1cc to the mandible without and with a spacer were 27.5, 68.7, and 85.8 Gy and 11.3, 53.6, and 64.9 Gy in cases 1, 2, and 3, respectively. No osteoradionecrosis of the jaw bones was observed in any case.

CONCLUSION

The spacer enabled maintenance of the distance between ¹⁹⁸Au grains, and between ¹⁹⁸Au grains and the jawbone. In buccal mucosa cancer, using a spacer in brachytherapy with ¹⁹⁸Au grains appears to reduce jawbone complications.

Endoscopic findings suggestive of a high risk of non-radical cure after definitive chemoradiotherapy for cT1bN0M0 esophageal squamous cell carcinoma

BACKGROUND

Definitive chemoradiotherapy (DCRT) is a curative treatment option for cT1bN0M0 esophageal squamous cell carcinoma (ESCC); however, local residual disease and recurrence after complete remission may occur. We aimed to identify endoscopic findings associated with the risk of non-radical cure (local remnant or recurrence) after DCRT for cT1bN0M0 ESCC.

METHODS

We retrospectively analyzed 40 consecutive patients with cT1bN0M0 ESCC who had undergone DCRT between January 2007 and December 2017. We examined the endoscopic findings in patients with residual or recurrent (RR) disease (RR group) and those without RR disease [non-RR (NRR) group] after DCRT. We also evaluated outcomes after DCRT for each endoscopic finding.

RESULTS

There were 10 patients in the RR group and 30 patients in the NRR group. The RR group had a significantly larger tumor size and a higher proportion of lesions with type 0-I. The 5-year relapse-free survival rate was significantly lower in type 0-I and in the presence of B3 vessels. Endoscopic findings in 15 patients with cT1bN0M0 ESCC, type 0-I, who underwent DCRT revealed significantly more reddish lesions in the RR group compared to the NRR group.

CONCLUSIONS

cT1bN0M0 ESCC large size, with B3 vessels, and type 0-I has a high risk of non-radical cure after DCRT, especially the reddish type 0-I, which may need to be considered for treatment similar to advanced cancer, including surgery with preoperative DCRT.

Long-term results of chemoradiotherapy with elective nodal irradiation for resectable locally advanced esophageal cancer in three-dimensional planning system

BACKGROUND

We evaluated the long-term results of definitive chemoradiotherapy (CRT) with elective nodal irradiation (ENI) using a three-dimensional (3D) planning system for resectable, locally advanced esophageal squamous cell carcinoma (LA-ESCC).

METHODS

This retrospective study included 65 patients with LA-ESCC who started CRT between 2006 and 2017. Patients with Stage I-IV LA-ESCC according to the Union for International Cancer Control TNM classification (eighth edition) were included. In stage IV, only supraclavicular lymph node (LN) metastasis was included. All patients received radiotherapy with ENI and concurrent chemotherapy with platinum and 5-fluorouracil.

RESULTS

The median age of the patients was 70 years (range 52-83 years). Stage I, II, III, and IV diseases were observed in 3 (5%), 28 (43%), 22 (34%), and 12 patients (18%), respectively. The median prescription dose was 66 Gy (range 50.4-66 Gy). The median follow-up period for the survivors was 71 months (range 8-175 months). The 5-year overall survival (OS) and progression-free survival rates were 54 and 43%, respectively. The 5-year OS rates for stages I-II and III-IV were 67 and 42%, respectively. Recurrence occurred in 29 patients (45%), and recurrence of regional LNs only occurred in 2 patients (3%). Grade 3 or higher late adverse events were observed in 8 patients (12%). Grade 5 heart failure occurred in two patients (3%); both had cardiovascular disease before treatment.

CONCLUSION

The long-term results of definitive CRT with ENI for resectable LA-ESCC were favorable. ENI with a 3D planning system may reduce regional LN recurrence and late adverse events.

Xenopus laevis Oocyte Array Fluidic Device Integrated with Microelectrodes for A Compact Two-Electrode Voltage Clamping System

We report on a compact two-electrode voltage clamping system composed of microfabricated electrodes and a fluidic device for Xenopus laevis oocytes. The device was fabricated by assembling Si-based electrode chips and acrylic frames to form fluidic channels. After the installation of Xenopus oocytes into the fluidic channels, the device can be separated in order to measure changes in oocyte plasma membrane potential in each channel using an external amplifier. Using fluid simulations and experiments, we investigated the success rates of Xenopus oocyte arrays and electrode insertion with respect to the flow rate. We successfully located each oocyte in the array and detected oocyte responses to chemical stimuli using our device.

A phase II study of concurrent chemoradiotherapy with 5-fluorouracil and mitomycin-C for squamous cell carcinoma of the anal canal (the JROSG 10-2 trial)

This study assessed the efficacy of chemoradiotherapy for squamous cell carcinoma of the anal canal (SCCAC). Patients with T1-4N0-3M0 SCCAC received chemoradiotherapy with 5-fluorouracil (5-FU, 800 mg/m2/day, 96-h infusion) and mitomycin-C (MMC, 10 mg/m2 bolus). Patients treated with 3-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiotherapy (IMRT) were administered 36.0 Gy in 20 fractions or 49.5 Gy in 33 fractions for elective nodal irradiation and 59.4 Gy in 33 fractions for primary tumor and metastatic nodal irradiation. The sample size was considered sufficient to estimate 95% confidence intervals (CIs) for the true 2-year disease-free survival (DFS) within a width of +15% when the expected true 2-year DFS was 70%. The primary endpoint was 2-year DFS. The secondary endpoints were 2-year overall survival (OS), locoregional control (LC), colostomy-free survival (CFS) and adverse events. Thirty-one patients were enrolled between January 2014 and July 2019. The median follow-up was 33.3 months (range, 16.2-65.8 months). Among the 31 patients, 13%, 32%, 16% and 39% had stage I, II, IIIA and IIIB disease, respectively. Thirty patients were treated with IMRT. Complete response (CR) was achieved in 27 patients. The 2-year DFS, OS, LC and CFS rates were 77.4% (95% CI, 58.4-88.5%), 93.5% (95% CI, 76.6-98.3%), 83.9% (95% CI, 65.5-92.9%) and 80.6% (95% CI, 61.9-90.8%), respectively. One patient experienced grade 3 late adverse events; however, no grade ≥ 4 late adverse events occurred. Good DFS with a low rate of late adverse events was observed. Chemoradiotherapy with 5-FU and MMC was effective for SCCAC.

Tolerance levels of mass density for adaptive helical tomotherapy using MVCT

Daily dose distributions for adaptive radiotherapy (ART) using helical tomotherapy (HT) are calculated using megavoltage computed tomography (MVCT). Generally, the MVCT number is converted to mass density (MD) using an MD calibration table (MVCT-MD table). The aims of this study are to calculate the tolerance levels of the MD for ART and to evaluate the tolerance levels using clinical patient plans. These tolerance levels of MD were calculated based on the tissue maximum ratio (TMR) of 6MV flattening-filter-free (FFF) beam of HT and the effective tissue thickness data from an International Commission on Radiological Protection 110 phantom data for lung, adipose/muscle and cartilage/spongy-bone. These tolerance levels were determined by considering both the MD causing a dose error of 2% and the variation in MVCT numbers. Subsequently, the stability of the MD values was estimated with the standard deviations (SD) in the MVCT number over 6 months. The dose distribution for clinical patient plans was calculated using the MVCT-MD table with added tolerance levels. These tolerance levels were determined as MD differences causing a dose error of 2%, and were ± 0.049 g/cm3, ± 0.030 g/cm3 and ± 0.049 g/cm3 for lung, adipose/muscle and cartilage/spongy-bone, respectively. The calculated dose distribution errors using the MVCT-MD table added tolerance levels were within 2%. We proposed these tolerance levels in MD for the quality control of the MVCT-MD table.

Influence of different air CT numbers for IVDT on the dose distribution in TomoTherapy MVCT

This study aims to evaluate the effect of different air computed tomography (CT) numbers of the image value density table (IVDT) on the retrospective dose calculation of head-and-neck (HN) radiotherapy using TomoTherapy megavoltage CT (MVCT) images. The CT numbers of the inside and outside air and each tissue-equivalent plug of the "Cheese" phantom were obtained from TomoTherapy MVCT. Two IVDTs with different air CT numbers were created and applied to MVCT images of the HN anthropomorphic phantom and recalculated by Planned Adaptive to verify dose distribution. We defined the recalculation dose with MVCT images using both inside and outside air of the IVDT as IVDT MVCT inair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{inair}}$ and IVDT MVCT outair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{outair}}$ , respectively. Treatment planning doses calculated on kVCT images were compared with those calculated on MVCT images using two different IVDT tables, namely, IVDT MVCT inair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{inair}}$ and IVDT MVCT outair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{outair}}$ . The difference between average MVCT numbers ±1 standard deviation on inside and outside air of the calibration phantom was 65 ± 36 HU. This difference in MVCT number of air exceeded the recommendation lung tolerance for dose calculation error of 2%. The dose differences between the planning target volume (PTV): D_98% , D_50% , D_2% and the organ at risk (OAR): D_max , D_mean recalculated by IVDT MVCT inair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{inair}}$ and IVDT MVCT outair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{outair}}$ using MVCT images were a maximum of 0.7% and 1.2%, respectively. Recalculated doses to the PTV and OAR with MVCT showed that IVDT MVCT outair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{outair}}$ was 0.5%-0.7% closer to the kVCT treatment planning dose than IVDT MVCT inair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{inair}}$ . This study showed that IVDT MVCT outair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{outair}}$ was more accurate than IVDT MVCT inair ${\mathrm{IVDT}}_{\mathrm{MVCT}}^{\mathrm{inair}}$ in recalculating the dose HN cases of MVCT using TomoTherapy.

Robust optimization of VMAT for prostate cancer accounting for geometric uncertainty

The aim of this study was to propose optimal robust planning by comparing the robustness with setup error with the robustness of a conventional planning target volume (PTV)‐based plan and to compare the robust plan to the PTV‐based plan for the target and organ at risk (OAR). Data from 13 patients with intermediate‐to‐high‐risk localized prostate cancer who did not have T3b disease were analyzed. The dose distribution under multiple setup error scenarios was assessed using a conventional PTV‐based plan. The clinical target volume (CTV) and OAR dose in moving coordinates were used for the dose constraint with the robust plan. The hybrid robust plan added the dose constraint of the PTV‐rectum to the static coordinate system. When the isocenter was shifted by 10 mm in the superior–inferior direction and 8 mm in the right‐left and anterior directions, the doses to the CTV, bladder, and rectum of the PTV‐based plan, robust plan, and hybrid robust plan were compared. For the CTV D_99% in the PTV‐based plan and hybrid robust plan, over 95% of the prescribed dose was secured in all directions, except in the inferior direction. There was no significant difference between the PTV‐based plan and the hybrid robust plan for rectum V_70Gy, V_60Gy, and V_40Gy. This study proposed an optimization method for patients with prostate cancer. When the setup error occurred within the PTV margin, the dose robustness of the CTV for the hybrid robust plan was higher than that of the PTV‐based plan, while maintaining the equivalent OAR dose.

Organs-at-risk dose constraints in head and neck intensity-modulated radiation therapy using a dataset from a multi-institutional clinical trial (JCOG1015A1)

Background

JCOG1015A1 is an ancillary research study to determine the organ-specific dose constraints in head and neck carcinoma treated with intensity-modulated radiation therapy (IMRT) using data from JCOG1015.

Methods

Individual patient data and dose-volume histograms of organs at risk (OAR) were collected from 74 patients with nasopharyngeal carcinoma treated with IMRT who enrolled in JCOG1015. The incidence of late toxicities was evaluated using the cumulative incidence method or prevalence proportion. ROC analysis was used to estimate the optimal DVH cut-off value that predicted toxicities.

Results

The 5-year cumulative incidences of Grade (G) 1 myelitis, ≥ G1 central nervous system (CNS) necrosis, G2 optic nerve disorder, ≥ G2 dysphagia, ≥ G2 laryngeal edema, ≥ G2 hearing impaired, ≥ G2 middle ear inflammation, and ≥ G1 hypothyroidism were 10%, 5%, 2%, 11%, 5%, 26%, 34%, and 34%, respectively. Significant associations between DVH parameters and incidences of toxicities were observed in the brainstem for myelitis (D1cc ≥ 55.8 Gy), in the brain for CNS necrosis (D1cc ≥ 72.1 Gy), in the eyeball for optic nerve disorder (Dmax ≥ 36.6 Gy), and in the ipsilateral inner ear for hearing impaired (Dmean ≥ 44 Gy). The optic nerve, pharyngeal constrictor muscle (PCM), and thyroid showed tendencies between DVH parameters and toxicity incidence. The prevalence proportion of G2 xerostomia at 2 years was 17 versus 6% (contralateral parotid gland Dmean ≥ 25.8 Gy vs less).

Conclusions

The dose constraint criteria were appropriate for most OAR in this study, although more strict dose constraints might be necessary for the inner ear, PCM, and brainstem.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13014-022-02105-3.

Development of a radiomics and machine learning model for predicting occult cervical lymph node metastasis in patients with tongue cancer

OBJECTIVE

We aimed to develop a predictive model for occult cervical lymph node metastasis in patients with tongue cancer using radiomics and machine learning from pretreatment contrast-enhanced computed tomography.

STUDY DESIGN

This study included 161 patients with tongue cancer who received local treatment. Computed tomography images were transferred to a radiomics platform. The volume of interest was the total neck node level, including levels Ia, Ib, II, III, and IVa at the ipsilateral side, and each neck node level. The dimensionality of the radiomics features was reduced using least absolute shrinkage and selection operator logistic regression analysis. We compared 5 classifiers with or without the synthetic minority oversampling technique (SMOTE).

RESULTS

For the analysis at the total neck node level, random forest with SMOTE was the best model, with an accuracy of 0.85 and an area under the curve score of 0.92. For the analysis at each neck node level, a support vector machine with SMOTE was the best model, with an accuracy of 0.96 and an area under the curve score of 0.98.

CONCLUSIONS

Predictive models using radiomics and machine learning have potential as clinical decision support tools in the management of patients with tongue cancer for prediction of occult cervical lymph node metastasis.

A prediction model for pathological findings after neoadjuvant chemoradiotherapy for resectable locally advanced esophageal squamous cell carcinoma based on endoscopic images using deep learning

OBJECTIVES

To propose deep-learning (DL)-based predictive model for pathological complete response rate for resectable locally advanced esophageal squamous cell carcinoma (SCC) after neoadjuvant chemoradiotherapy (NCRT) with endoscopic images.

METHODS AND MATERIAL

This retrospective study analyzed 98 patients with locally advanced esophagus cancer treated by preoperative chemoradiotherapy followed by surgery from 2004 to 2016. The patient data were split into two sets: 72 patients for the training of models and 26 patients for testing of the model. Patients was classified into two groups with the LC (Group I: responder and Group II: non-responder). The scanned images were converted into joint photographic experts group (JPEG) format and resized to 150 × 150 pixels. The input image without imaging filter (w/o filter) and with Laplacian, Sobel, and wavelet imaging filters deep-learning model to predict the pathological CR with a convolution neural network (CNN). The accuracy, sensitivity, and specificity, the area under the curve (AUC) of the receiver operating characteristic were evaluated.

RESULTS

The average of accuracy for the cross-validation was 0.64 for w/o filter, 0.69 for Laplacian filter, 0.71 for Sobel filter, and 0.81 for wavelet filter, respectively. The average of sensitivity for the cross-validation was 0.80 for w/o filter, 0.81 for Laplacian filter, 0.67 for Sobel filter, and 0.80 for wavelet filter, respectively. The average of specificity for the cross-validation was 0.37 for w/o filter, 0.55 for Laplacian filter, 0.68 for Sobel filter, and 0.81 for wavelet filter, respectively. From the ROC curve, the average AUC for the cross-validation was 0.58 for w/o filter, 0.67 for Laplacian filter, 0.73 for Sobel filter, and 0.83 for wavelet filter, respectively.

CONCLUSIONS

The current study proposed the improvement the accuracy of the DL-based prediction model with the imaging filters. With the imaging filters, the accuracy was significantly improved. The model can be supported to assist clinical oncologists to have a more accurate expectations of the treatment outcome.

ADVANCES IN KNOWLEDGE

The accuracy of the prediction for the local control after radiotherapy can improve with the input image with the imaging filter for deep learning.

Current update of treatment strategies for borderline resectable pancreatic cancer: a narrative review

Background and Objective

Borderline resectable pancreatic cancer (BRPC) is a tumor that infiltrates into the large blood vessels, with a high probability that the tumor will remain after surgical resection. To date, there has been no confirmed treatment strategy for BRPC. However, high-level studies, such as those using the intention-to-treat analysis, have recently been published. This review aimed to update the current status of treatment strategies for BRPC.

Methods

We searched for studies, including those investigating patients with BRPC, either treated by upfront surgery or with neoadjuvant treatment and reported the R0 resection rate and overall survival using an intention-to-treat analysis.

Key Content and Findings

Consequently, 22 articles were identified. Twelve were prospective studies. Six studies compared neoadjuvant therapy with upfront surgery, and both the R0 resection rate and overall survival in patients who underwent upfront surgery were significantly worse than in those who underwent neoadjuvant treatment in all studies. Six studies evaluated neoadjuvant chemotherapy, while 15 studies neoadjuvant chemoradiation. No reports showed the superiority or inferiority of the two methods, and the optimal regimen was not determined in either treatment. The high-precision radiation therapy techniques have been studied, but the optimal method and dose fractionation were unclear.

Conclusions

The current standard of care for the BRPC is neoadjuvant therapy. Although the optimal regimen of neoadjuvant therapy was not determined, several prospective trials are underway to identify the optimal neoadjuvant treatment.

Clinical Outcomes of Esophagectomy and Chemoradiotherapy After Endoscopic Resection for Superficial Esophageal Squamous Cell Carcinoma

BACKGROUND/AIM

Surgical resection and chemoradiotherapy (CRT) can be performed as additional treatments for superficial esophageal cancer after endoscopic resection, but the selection criteria vary depending on the institution. We retrospectively evaluated the outcomes of patients with endoscopically resected superficial esophageal cancer treated with surgical resection and CRT at our institution.

PATIENTS AND METHODS

The outcomes of 67 cases of additional treatment after endoscopic resection of superficial esophageal cancer, excluding adenocarcinoma, performed at our hospital from January 2000 to June 2017 were compared (30 cases in the surgery group and 37 cases in the CRT group).

RESULTS

In the surgery group, eight patients had lymph node metastasis and two had recurrence in the supraclavicular fossa lymph nodes after surgery, therefore reoperation was performed. There were no deaths from esophageal cancer, and the 5-year survival rate was 92.6%. One patient in the CRT group had a recurrence in the cervical paraoesophageal lymph node, which was resected, but no death from esophageal cancer was observed, and the 5-year survival rate was 81.0%. The 5-year survival rate was significantly better in the surgery group than in the CRT group (p=0.039). The greater number of elderly patients in the CRT group was considered to be the reason for the worse prognosis, Conclusion: Although the prognosis of esophagectomy or chemoradiotherapy (CRT) is very favorable, CRT is considered to be the preferred additional treatment after endoscopic resection of superficial esophageal cancer without lymph node metastasis from the viewpoint of organ preservation.

High-power laser experiment forming a supercritical collisionless shock in a magnetized uniform plasma at rest

We present an experimental method to generate quasiperpendicular supercritical magnetized collisionless shocks. In our experiment, ambient nitrogen (N) plasma is at rest and well magnetized, and it has uniform mass density. The plasma is pushed by laser-driven ablation aluminum (Al) plasma. Streaked optical pyrometry and spatially resolved laser collective Thomson scattering clarify structures of plasma density and temperatures, which are compared with one-dimensional particle-in-cell simulations. It is indicated that just after the laser irradiation, the Al plasma is magnetized by a self-generated Biermann battery field, and the plasma slaps the incident N plasma. The compressed external field in the N plasma reflects N ions, leading to counterstreaming magnetized N flows. Namely, we identify the edge of the reflected N ions. Such interacting plasmas form a magnetized collisionless shock.

Baseline drift vector of multiple points on body surface using a near-infrared camera

The purpose of this study was to extract the three-dimensional (3D) vector of the baseline drift baseline drift vector (BDV) of the specific points on the body surface and to demonstrate the importance of the 3D tracking of the body surface. Our system consisted of a near-infrared camera (NIC: Kinect V2) and software that recognized and tracked blue stickers as markers. We acquired 3D coordinates of 30 markers stuck on the body surface for 30 min for eight healthy volunteers and developed a simple technique to extract the BDV. The BDV on the sternum, rib, and abdomen was extracted from the measured data. BDV per min. was analyzed to estimate the frequency to exceed a given tolerance. Also, the correlation among BDVs for multiple body sites was analyzed. The longitudinal baseline drift was observed in the BDV of healthy volunteers. Among the eight volunteers, the maximum probability that the BDV per min. exceeded the tolerance of 1 mm and 2 mm was 30% and 15%, respectively. The correlation among BDVs of multiple body sites suggested a potential feasibility to distinguish the translational movement of the whole area and the respiratory movement. In conclusion, we constructed the 3D tracking system of multiple points on the body surface using a noninvasive NIC at a low cost and established the method to extract the BDV. The existence of the longitudinal baseline drift showed the importance of the 3D tracking in the body surface.

Reirradiation Using 198Au Grain Brachytherapy for Recurrent Oral Cancer Cases Previously Treated by Definitive Radiotherapy

BACKGROUND/AIM

We investigated treatment outcomes and complications during reirradiation of patients with oral cancers.

PATIENTS AND METHODS

Six patients who received definitive radiotherapy for oral cancer as the initial treatment and brachytherapy for recurrence were included. Local control and overall survival rates, soft tissue and mandibular complications, and tooth extraction were investigated.

RESULTS

The five-year local control and overall survival rates were 83.3% and 100%, respectively. The occurrence rate of grade 2 soft tissue and mandible complications was 33.3%, and the primary sites were the buccal mucosa and the floor of mouth. The positions of the extracted tooth in the two cases were adjacent to the tumor, and one case developed grade 2 complication of the mandible.

CONCLUSION

During recurrence of the buccal mucosa and the floor of mouth cancers, reirradiation should be avoided considering mandibular complications. To avoid reirradiation-related complications, tooth extraction near the radiation field should be avoided.

Potential benefits of volumetric modulated arc therapy to reduce the incidence of ≥ grade 2 radiation pneumonitis in radiotherapy for locally advanced non-small cell lung cancer patients

BACKGROUND

The use of volumetric modulated arc therapy is gradually widespread for locally advanced non-small cell lung cancer. The purpose of this study was to identify the factors that caused ≥ grade 2 radiation pneumonitis and evaluate the impact of using volumetric modulated arc therapy on the incidence of ≥ grade 2 radiation pneumonitis by comparing three-dimensional conformal radiation therapy.

METHODS

We retrospectively evaluated 124 patients who underwent radical radiotherapy for locally advanced non-small cell lung cancer in our institution between 2008 and 2019. The following variables were analysed to detect the factors that affected ≥ grade 2 radiation pneumonitis; age, sex, the presence of interstitial lung disease, pulmonary emphysema, tumour location, stage, PTV/lung volume, lung V20Gy, total dose, concurrent chemoradiotherapy, adjuvant immune checkpoint inhibitor, radiotherapy method. Radiation pneumonitis was evaluated using the common terminology criteria for adverse events (version 5.0).

RESULTS

A total of 84 patients underwent three-dimensional conformal radiation therapy (3D-CRT group) and 40 patients underwent volumetric modulated arc therapy (VMAT group). The cumulative incidence of ≥ grade 2 radiation pneumonitis at 12 months was significantly lower in the VMAT group than in the 3D-CRT group (25% vs. 49.1%). The use of volumetric modulated arc therapy was a significant factor for ≥ grade 2 radiation pneumonitis (HR:0.32, 95% CI: 0.15-0.65, P = 0.0017) in addition to lung V20Gy (≥ 24%, HR:5.72 (95% CI: 2.87-11.4), P < 0.0001) and total dose (≥ 70 Gy, HR:2.64 (95% CI: 1.39-5.03), P = 0.0031) even after adjustment by multivariate analysis.

CONCLUSIONS

We identified factors associated with ≥ grade 2 radiation pneumonitis in radiotherapy for patients with locally advanced non-small cell lung cancer. Volumetric modulated arc therapy has potential benefits to reduce the risk of ≥ grade 2 radiation pneumonitis.

Treatment outcomes of real-time intraoral sonography-guided implantation technique of 198Au grain brachytherapy for T1 and T2 tongue cancer

It is often challenging to determine the accurate size and shape of oral lesions through computed tomography (CT) or magnetic resonance imaging (MRI) when they are very small or obscured by metallic artifacts, such as dental prostheses. Intraoral ultrasonography (IUS) has been shown to be beneficial in obtaining precise information about total tumor extension, as well as the exact location and guiding the insertion of catheters during interstitial brachytherapy. We evaluated the role of IUS in assessing the clinical outcomes of interstitial brachytherapy with 198Au grains in tongue cancer through a retrospective medical chart review. The data from 45 patients with T1 (n = 21) and T2 (n = 24) tongue cancer, who were mainly treated with 198Au grain implants between January 2005 and April 2019, were included in this study. 198Au grain implantations were carried out, and positioning of the implants was confirmed by IUS, to ensure that 198Au grains were appropriately placed for the deep border of the tongue lesion. The five-year local control rates of T1 and T2 tongue cancers were 95.2% and 95.5%, respectively. We propose that the use of IUS to identify the extent of lesions and the position of implanted grains is effective when performing brachytherapy with 198Au grains.

A prediction model for degree of differentiation for resectable locally advanced esophageal squamous cell carcinoma based on CT images using radiomics and machine-learning

OBJECTIVE

To propose the prediction model for degree of differentiation for locally advanced esophageal cancer patients from the planning CT image by radiomics analysis with machine learning.

METHODS

Data of 104 patients with esophagus cancer, who underwent chemoradiotherapy followed by surgery at the Hiroshima University hospital from 2003 to 2016 were analyzed. The treatment outcomes of these tumors were known prior to the study. The data were split into 3 sets: 57/16 tumors for the training/validation and 31 tumors for model testing. The degree of differentiation of squamous cell carcinoma was classified into two groups. The first group (Group I) was a poorly differentiated (POR) patients. The second group (Group II) was well and moderately differentiated patients. The radiomics feature was extracted in the tumor and around the tumor regions. A total number of 3480 radiomics features per patient image were extracted from radiotherapy planning CT scan. Models were built with the least absolute shrinkage and selection operator (LASSO) logistic regression and applied to the set of candidate predictors. The radiomics features were used for the input data in the machine learning. To build predictive models with radiomics features, neural network classifiers was used. The precision, accuracy, sensitivity by generating confusion matrices, the area under the curve (AUC) of receiver operating characteristic curve were evaluated.

RESULTS

By the LASSO analysis of the training data, we found 13 radiomics features from CT images for the classification. The accuracy of the prediction model was highest for using only CT radiomics features. The accuracy, specificity, and sensitivity of the predictive model were 85.4%, 88.6%, 80.0%, and the AUC was 0.92.

CONCLUSION

The proposed predictive model showed high accuracy for the classification of the degree of the differentiation of esophagus cancer. Because of the good prediction ability of the method, the method may contribute to reducing the pathological examination by biopsy and predicting the local control.

ADVANCES IN KNOWLEDGE

For esophageal cancer, the differentiation of degree is the import indexes reflecting the aggressiveness. The current study proposed the prediction model for the differentiation of degree with radiomics analysis.