A novel CT-based radiomics model for predicting response and prognosis of chemoradiotherapy in esophageal squamous cell carcinoma.

No clinically relevant biomarker has been identified for predicting the response of esophageal squamous cell carcinoma (ESCC) to chemoradiotherapy (CRT). Herein, we established a CT-based radiomics model with artificial intelligence (AI) to predict the response and prognosis of CRT in ESCC. A total of 44 ESCC patients (stage I-IV) were enrolled in this study; training (n = 27) and validation (n = 17) cohorts. First, we extracted a total of 476 radiomics features from three-dimensional CT images of cancer lesions in training cohort, selected 110 features associated with the CRT response by ROC analysis (AUC ≥ 0.7) and identified 12 independent features, excluding correlated features by Pearson's correlation analysis (r ≥ 0.7). Based on the 12 features, we constructed 5 prediction models of different machine learning algorithms (Random Forest (RF), Ridge Regression, Naive Bayes, Support Vector Machine, and Artificial Neural Network models). Among those, the RF model showed the highest AUC in the training cohort (0.99 [95%CI 0.86-1.00]) as well as in the validation cohort (0.92 [95%CI 0.71-0.99]) to predict the CRT response. Additionally, Kaplan-Meyer analysis of the validation cohort and all the patient data showed significantly longer progression-free and overall survival in the high-prediction score group compared with the low-prediction score group in the RF model. Univariate and multivariate analyses revealed that the radiomics prediction score and lymph node metastasis were independent prognostic biomarkers for CRT of ESCC. In conclusion, we have developed a CT-based radiomics model using AI, which may have the potential to predict the CRT response as well as the prognosis for ESCC patients with non-invasiveness and cost-effectiveness.

Effect of Positive Biopsy Core Rate on Low-dose-rate Brachytherapy Outcomes in Intermediate-risk Prostate Cancer.

BACKGROUND/AIM: Intermediate-risk prostate cancer (PCa) is a highly heterogeneous disease. Although low-dose-rate brachytherapy (LDR-BT) is mainly used for low- to intermediate-risk PCa, limited reports have evaluated the detailed differences in outcomes, including differences between patients with ISUP grade group (GG) 2 and GG3 intermediate-risk PCa. This study aimed to investigate the differences in outcomes between intermediate-risk Japanese patients with GG2 and GG3 PCa who underwent LDR-BT. PATIENTS AND METHODS: This single-center retrospective study included 342 consecutive patients with intermediate-risk PCa; 232 patients with GG2 and 110 with GG3 were treated with LDR-BT at Tokushima University Hospital between July 2004 and December 2019. RESULTS: No significant difference in 5-year biochemical progression-free survival and cancer-specific survival was observed between patients with GG2 and those with GG3 (p=0.649 and p=0.633, respectively). Multivariate analysis showed that radiation doses up to 90% of the prostate volume (D90) and the percentage of positive cores were predictors of recurrence in all patients with intermediate-risk PCa. Group analyses showed that D90 was a predictor for recurrence in patients with GG2. In contrast, a high percentage of positive cores was a significant risk factor for recurrence in patients with GG3. CONCLUSION: Positive core ratios observed on prostate biopsy correlated with higher recurrence rates after LDR-BT. This indicates that the proportion of positive cores in the biopsy may be an important factor in predicting the likelihood of recurrence, especially for patients with GG3 PCa.

Prostate-specific Antigen Levels Following Brachytherapy Impact Late Biochemical Recurrence in Japanese Patients With Localized Prostate Cancer.

BACKGROUND/AIM: Evaluation of long-term outcomes is essential for the successful treatment of localized prostate cancer; however, the risk of late recurrence following brachytherapy is still not clear. This study aimed to evaluate the long-term outcomes of low-dose-rate brachytherapy (LDR-BT) for localized prostate cancer in Japanese patients and identify factors associated with late recurrence after treatment. PATIENTS AND METHODS: This single-center, cohort study included patients who underwent LDR-BT at the Tokushima University Hospital in Japan between July 2004 and January 2015; 418 patients, who were followed-up at least 7 years after LDR-BT, were included in the study. Biochemical progression free survival (bPFS) was defined according to the Phoenix definition (nadir PSA+2 ng/ml) and bPFS and cancer specific survival (CSS) were calculated using Kaplan-Meier survival curves. Univariate and multivariate analyses were performed using Cox proportional hazard regression models. RESULTS: Approximately half of the patients with PSA >0.5 ng/ml at 5 years after LDR-BT had a recurrence within the next 2 years. However, only 1.4% of the patients with a PSA ≤0.2 ng/ml at 5 years post-treatment showed tumor recurrence, including those at high risk of treatment failure according to the D'Amico classification. In multivariate analysis, PSA level at 5 years post-treatment was the only predictor of late recurrence after 7 years of treatment. CONCLUSION: PSA levels at 5 years post-treatment were associated with long-term recurrence of localized prostate cancer, which can help alleviate patient anxiety concerning prostate cancer recurrence if PSA levels remain low at 5 years after LDR-BT.

Differences between professionals in treatment planning for patients with stage III lung cancer using treatment-planning QA software.

Background: The quality of treatment planning for stage III non-small cell lung cancer varies within and between facilities due to the different professions involved in planning. Dose estimation parameters were calculated using a feasibility dose-volume histogram (FDVH) implemented in the treatment planning quality assurance software PlanIQ. This study aimed to evaluate differences in treatment planning between occupations using manual FDVH-referenced treatment planning to identify their characteristics. Materials and methods: The study included ten patients with stage III non-small cell lung cancer, and volumetric-modulated arc therapy was used as the treatment planning technique. Fifteen planners, comprising five radiation oncologists, five medical physicists, and five radiological technologists, developed treatment strategies after referring to the FDVH. Results: Medical physicists had a higher mean dose at D98% of the planning target volume (PTV) and a lower mean dose at D2% of the PTV than those in other occupations. Medical physicists had the lowest irradiation lung volumes (V5 Gy and V13 Gy) compared to other professions, and radiation oncologists had the lowest V20 Gy and mean lung dose. Radiological technologists had the highest irradiation volumes for dose constraints at all indexes on the normal lung volume. Conclusions: The quality of the treatment plans developed in this study differed between occupations due to their background expertise, even when an FDVH was used as a reference. Therefore, discussing and sharing knowledge and treatment planning techniques among professionals is essential to determine the optimal treatment plan for each facility and patient.

Extreme leanness, lower skeletal muscle quality, and loss of muscle mass during treatment are predictors of poor prognosis in cervical cancer treated with concurrent chemoradiation therapy.

BACKGROUND: Human papillomavirus vaccination is not widespread in Japan, and the low screening rates result in many cases of locally advanced cervical cancer. We investigated the prognostic significance of sarcopenia in patients with cervical cancer to guide healthcare policies to improve treatment outcomes. METHODS: This retrospective study included 83 patients with cervical cancer without distant metastasis who underwent primary concurrent chemoradiotherapy between 2013 and 2018. We analyzed the indicators of physical condition and muscle quantity using the SYNAPSE VINCENT software. Muscle mass and the relationship between treatment toxicity and prognosis were evaluated. RESULTS: The patients' median age was 60 (range 33‒80) years. Cancer stage distribution was as follows: cT2b or higher, 84.3%; N1, 65.1%; and MA, 27.7%. The overall sarcopenia (skeletal muscle index [SMI] < 38.5) rate was 30.1%, and the rate was 33.9 and 22.2% in patients aged < 64 and ≥ 65 years, respectively. No correlation was observed between clinical stage and musculoskeletal indices. Treatment resulted in decreased body weight and SMI; after treatment, the sarcopenia rate increased to 37.3%. A higher intramuscular adipose tissue content (IMAC) reduced the number of chemotherapy cycles needed. Treatment-associated SMI decreases of ≥ 7% indicated poor prognosis, with significant differences in progression-free survival and overall survival (p = 0.013 and p = 0.012, respectively). Patients who were very lean (body mass index < 18.5 kg/m2) before treatment had a poor prognosis (p = 0.016 and p < 0.001). CONCLUSIONS: Our findings emphasize the importance of assessing original nutritional status and maintaining muscle mass and quality during the treatment of patients with cervical cancer.

Effect of dental metal artifact conversion volume on dose distribution in head-and-neck volumetric-modulated arc therapy.

PURPOSE: During treatment planning for head-and-neck volumetric-modulated arc therapy (VMAT), manual contouring of the metal artifact area of artificial teeth is done, and the area is replaced with water computed tomography (CT) values for dose calculation. This contouring of the metal artifact areas, which is performed manually, is subject to human variability. The purpose of this study is to evaluate and analyze the effect of inter-observer variation on dose distribution. METHODS: The subjects were 25 cases of cancer of the oropharynx for which VMAT was performed. Six radiation oncologists (ROs) performed metal artifact contouring for all of the cases. Gross tumor volume, clinical target volume, planning target volume (PTV), and oral cavity were evaluated. The contouring of the six ROs was divided into two groups, small and large groups. A reference RO was determined for each group and the dose distribution was compared with those of the other radiation oncologists by gamma analysis (GA). As an additional experiment, we changed the contouring of each dental metal artifact area, creating enlarged contours (L), reduced contours (S), and undrawn contours (N) based on the contouring by the six ROs and compared these structure sets. RESULTS: The evaluation of inter-observer variation showed no significant difference between the large and small groups, and the GA pass rate was 100%. Similar results were obtained comparing structure sets L and S, but in the comparison of structure sets L and N, there were cases with pass rates below 70%. CONCLUSIONS: The results show that the artificial variability of manual artificial tooth metal artifact contouring has little effect on the dose distribution of VMAT. However, it should be noted that the dose distribution may change depending on the contouring method in cases where the overlap between PTV and metal artifact areas is large.

Clinical outcomes and prognostic factors of definitive radiotherapy for esophageal cancer.

Purpose To assess the treatment results of definitive radiotherapy for esophageal cancer at Tokushima University Hospital and clarify the prognostic factors. Methods Seventy consecutive patients with esophageal cancer who underwent definitive radiotherapy between May 2004 and March 2012 were included in the present study. Local control rate, overall survival rate, and radiation morbidity were examined and univariate and multivariate analyses were performed to investigate prognostic factors. Results The 5-yearoverall survival rates of stages I, II, III, and IVA were 81%, 71%, 0%, and 9%, respectively. Performance status, clinical stage, and neoadjuvant chemotherapy were significant prognostic factors. A past history of interstitial pneumonia was associated with severe radiation-induced lung injury. Conclusions Patients who underwent definitive chemoradiotherapy for esophageal cancer in stage I/II showed good prognosis. However, treatment results of the patients in stage III/IV were not satisfactory, and those who could not undergo surgery after neoadjuvant chemotherapy had the worst prognosis.J.Med.Invest.66:99-105, February, 2019.

Clinical outcomes of hypofractionated image-guided multifocal irradiation using volumetric-modulated arc therapy for brain metastases.

Volumetric-modulated arc therapy (VMAT) can be used to design hypofractionated radiotherapy treatment plans for multiple brain metastases. The purpose of this study was to evaluate treatment outcomes of hypofractionated image-guided multifocal irradiation using VMAT (HFIGMI-VMAT) for brain metastases. From July 2012 to December 2016, 67 consecutive patients with 601 brain metastases were treated with HFIGMI-VMAT at our institution. The prescribed dose was 50 Gy to a 95% volume of the planning target volume in 10 fractions. Fifty-five of the 67 patients had non-small-cell lung cancer, and the remaining 12 had other types of cancer. The median number of brain metastases was five, and the median maximum diameter was 1.2 cm. The median duration of follow-up was 12.0 months (range, 1.9-44.8 months), and the median survival time 18.7 months. Four patients with six lesions had local recurrences. The local control rate in the 64 assessed patients was 98.4% and 95.3% at 6 and 12 months, respectively (three died before assessment). The local control rate for the 572 assessed lesions was 99.8% and 99.3% at 6 and 12 months, respectively. Thirty-nine patients developed distant brain metastases, the distant brain control rate being 59.7% and 40.5% at 6 and 12 months, respectively. Acute toxicities were generally mild (Grade 1-2). Three patients (4.5%) developed radiation necrosis requiring corticosteroid therapy. The HFIGMI-VMAT technique with flat dose delivery was well tolerated and achieved excellent local control. This technique is a promising treatment option for patients with multiple and large brain metastases.