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.

Prediction of Tumor PD-L1 Expression in Resectable Non-Small Cell Lung Cancer by Machine Learning Models Based on Clinical and Radiological Features: Performance Comparison With Preoperative Biopsy.

OBJECTIVE: We investigated if PD-L1 expression can be predicted by machine learning using clinical and imaging features. METHODS: We included 117 patients with c-stage I/II non-small cell lung cancer who underwent radical resection. A total of 3951 radiomic features were extracted by defining the tumor (within tumor contour), rim (contour ±3 mm) and exterior (contour +10 mm) on preoperative contrast computed tomography. After feature selection by Boruta algorithm, prediction models of tumor PD-L1 expression (22C3: ≥1%, <1%) of resected specimens were constructed using Random Forest: radiomics, clinical, and combined models. Their performance was evaluated by 5-fold cross-validation, and AUCs were compared using Delong test. Next, study groups were categorized as patients without biopsy (training set), and those with biopsy (test set). Predictive ability of biopsy was compared to each prediction model. RESULTS: Of 117 patients (66 ± 10 years old, 48% male), 33 (28.2%) had PD-L1≥1%. Mean AUC of PD-L1≥1% for the validation set in radiomics, clinical, and combined models were 0.80, 0.80, and 0.83 (P = .32 vs. clinical model), respectively. The diagnosis of malignancy was made in 22 of 38 (58%) patients with attempted biopsies, and PD-L1 was measurable in 19 of 38 (50%) patients. Diagnostic accuracies of PD-L1≥1% from 19 determinable biopsies and 38 all attempted biopsies were 0.68 and 0.34, respectively. These were out performed by machine learning: 0.71, 0.71, and 0.74 for radiomics, clinical, and combined models, respectively. CONCLUSIONS: Our machine learning could be an adjunctive tool in estimating PD-L1 expression prior to neoadjuvant treatment, particularly when PD-L1 is indeterminable with biopsy.

Detection of EGFR mutations in early-stage lung adenocarcinoma by machine learning-based radiomics.

Background: We hypothesized that epidermal growth factor receptor (EGFR) mutations could be detected in early-stage lung adenocarcinoma using radiomics. Methods: This retrospective study included consecutive patients with clinical stage I/II lung adenocarcinoma who underwent curative-intent pulmonary resection from March-December 2016. Using preoperative enhanced chest computed tomography, 3,951 radiomic features were extracted in total from the tumor (area within the tumor boundary), tumor rim (area within ±3 mm of the tumor boundary), and tumor exterior (area between +10 mm outside the tumor and tumor boundary). A machine learning-based radiomics model was constructed to detect EGFR mutations. The combined model incorporated both radiomic and clinical features (gender and smoking history). The performance was validated with five-fold cross-validation and evaluated using the mean area under the curve (AUC). Results: Of 99 patients (mean age, 66±11 years; female, 66.6%; clinical stage I/II, 89.9%/10.1%), EGFR mutations in the surgical specimen were detected in 46 (46.5%). A median of 4 (range, 2 to 8) radiomic features was selected for each validation session. The mean AUCs in the radiomics and combined models were 0.75 and 0.83, respectively. The two top-ranked features in the combined model were the radiomic features extracted from the tumor exterior and the tumor, indicating a higher impact of radiomic features over relevant clinical features. Conclusions: Radiomic features, including those in the peri-tumoral area, may help detect EGFR mutations in lung adenocarcinomas in preoperative settings. This non-invasive image-based technology could help guide future precision neoadjuvant therapy.

Intensity-modulated radiation therapy for intermediate-risk prostate cancer: does ADT still have an impact in the dose-escalated external beam radiation therapy era?

BACKGROUND: This study aimed to investigate the effect of androgen deprivation therapy (ADT) on the survival of intermediate-risk prostate cancer (IR-PCA) patients treated with dose-escalated external beam radiation therapy (DE-EBRT), and to determine the group that will benefit from ADT. METHODS: We analysed 620 IR-PCA patients treated with DE-EBRT at two institutions. Variables were adjusted using the stabilised inverse probability of treatment weighting method (sIPTW) between radiation therapy (RT) and RT plus ADT groups. Biochemical relapse-free survival (bRFS) rate and overall survival (OS) rate were compared using Kaplan-Meier analysis and log-rank test. Cox proportional hazard analysis (CPH) was conducted to detect unfavorable risk factors. RESULTS: This study included 405 patients; with 217 and 188 patients in the RT and RT plus ADT groups, respectively. The prescribed radiation dose was 78 Gy in 39 fractions. The median follow-up time was 82.0 months. After sIPTW-adjustment, 214.3 and 189.7 patients were assigned to the RT and RT plus ADT groups, respectively. The 7-year bRFS and OS were 89.3% and 94.6% in RT group and 92.3% and 91.0% in RT plus ADT group, respectively. Before and after sIPTW adjustment, no statistically significant differences were found in these endpoints between treatment groups. Multivariate CPH for bRFS revealed Gleason score (GS) 4 + 3 as an unfavorable risk factor, and ADT improved biochemical control of them. CONCLUSION: ADT may not always be effective in all Japanese IR-PCA patients treated with DE-EBRT, but it can improve biochemical control in patients with GS 4 + 3.

A Japanese prospective multi-institutional feasibility study on accelerated partial breast irradiation using multicatheter interstitial brachytherapy: clinical results with a median follow-up of 60 months.

BACKGROUND: We carried out the first multi-institutional prospective study on accelerated partial breast irradiation (APBI) via multicatheter interstitial brachytherapy in a shorter period for early breast cancer in Japan. METHODS: Patient eligibility criteria included positive hormone receptors, tumors ≤ 3 cm and TNM stage pN0M0. After breast-conserving surgery (Japanese cylindrical resection) and histological confirmation of negative surgical margins and the absence of lymph node metastasis, applicator implantation was performed either postoperatively or intraoperatively. High-dose-rate brachytherapy of 36 Gy in 6 fractions was delivered. RESULTS: Forty-six patients from six institutions received this treatment regimen, and the median follow-up time was 60 months (range 57-67 months). The median resected breast tissue volume was 81 cm3 (range 28-260 cm3). No Grade 4 late sequela, local recurrence nor death due to breast cancer were observed. Grade 2-3 sequelae such as rib fracture (2%), soft tissue necrosis (9%), fibrosis (20%), and breast pain (9%) were observed. The resected breast tissue volumes of the patients who had Grade ≥ 2 fibrosis and Grade < 2 fibrosis were 105.9 ± 32.3 cm3 and 76.3 ± 45.6 cm3, respectively, p = 0.02. The overall cosmetic outcome score of Excellent/Good was 74% at 60 months after APBI. Grade ≥ 1 fibrosis was observed in 44% and 92% of patients who scored Excellent/Good and Fair/Poor, respectively, p = 0.004. CONCLUSIONS: This study showed excellent local control and survival results with minimal late sequelae.

Long-term outcomes and central nervous system relapse in extranodal natural killer/T-cell lymphoma.

To elucidate the long-term outcomes of non-anthracycline-containing therapies and central nervous system (CNS) events in patients with extranodal NK/T-cell lymphoma, nasal type (ENKTL), the clinical data of 313 patients with ENKTL diagnosed between 2000 and 2013 in a nationwide retrospective study in Japan were updated and analyzed. At a median follow-up of 8.4 years, the 5-year overall survival (OS) and progression-free survival (PFS) were 71% and 64%, respectively, in 140 localized ENKTL patients who received radiotherapy-dexamethasone, etoposide, ifosfamide, and carboplatin (RT-DeVIC) in clinical practice. Nine (6.4%) patients experienced second malignancies. In 155 localized ENKTL patients treated with RT-DeVIC, 10 (6.5%) experienced CNS relapse (median, 12.8 months after diagnosis). In five of them, the events were confined to the CNS. Nine of the 10 patients who experienced CNS relapse died within 1 year after CNS relapse. Multivariate analysis identified gingival (hazard ratio [HR], 54.35; 95% confidence interval [CI], 8.60-343.35) and paranasal involvement (HR, 7.42; 95% CI, 1.78-30.89) as independent risk factors for CNS relapse. In 80 advanced ENKTL patients, 18 received steroid (dexamethasone), methotrexate, ifosfamide, L-asparaginase, and etoposide (SMILE) chemotherapy as first-line treatment. Patients who received SMILE as their first-line treatment tended to have better OS than those who did not (p = 0.071). Six (7.5%) advanced ENKTL patients experienced isolated CNS relapse (median, 2.6 months after diagnosis) and died within 4 months of relapse. No second malignancies were documented in advanced ENKTL patients. In the entire cohort, the median OS after first relapse or progression was 4.6 months. 12 patients who survived 5 years after PFS events were disease-free at the last follow-up. Of those, 11 (92%) underwent hematopoietic stem cell transplantation. Our 8-year follow-up revealed the long-term efficacy and safety of RT-DeVIC and SMILE. The risk of CNS relapse is an important consideration in advanced ENKTL.

Dosimetric comparison between three-dimensional conformal radiotherapy followed by electron beam boost and volumetric modulated arc therapy using concomitant boost for the heart and cardiac segments in patients with left-sided breast cancer at risk for radiation-induced cardiac toxicity.

PURPOSE: We aimed to compare dosimetric parameters between three-dimensional conformal radiation therapy followed by electron beam boost (3D-CRT + EB) and volumetric modulated arc therapy using simultaneous integrated boost (SIB-VMAT) in left-sided breast cancer patients. METHODS: This study included 57 patients with left-sided breast cancer who underwent SIB-VMAT. All patients had a computed tomography-based maximum heart distance of ≥ 1 cm and were prescribed a dose of 42.56 Gy/16 fractions to the planning target volume and a concomitant-boosted target dose of 53.2 Gy or 51.2 Gy. The 3D-CRT + EB plan was retrospectively created for the purpose of comparison using tangential fields with field-in-field technique followed by electron beam irradiation. RESULTS: The doses to the clinical target volume significantly improved in the SIB-VMAT plans. All dosimetric parameters for the left anterior descending coronary artery (LAD) and LAD middle position (LAD mid) in the SIB-VMAT plans were significantly lower than those for 3D-CRT + EB plans (P < 0.01), while the doses to the heart, lung, contralateral breast and non-target tissue were decreased in the 3D-CRT + EB plans compared with those in the SIB-VMAT plans (e.g., 1.9 Gy vs. 2.9 Gy; P < 0.001 for the mean dose of heart). CONCLUSIONS: SIB-VMAT significantly improved the dose to the target while reducing the doses to the LAD and LAD mid, whereas 3D-CRT + EB significantly decreased the doses to the heart and other organs at risk in patients with left-sided breast cancer at risk for radiation-induced coronary artery disease.

Outcomes of intensity-modulated radiation therapy for intermediate- or high-risk prostate cancer: a single-institutional study.

BACKGROUND: There are few reports from Japan about the outcomes of intensity-modulated radiation therapy for localized prostate cancer. This study was aimed at assessing the efficacy and toxicity of intensity-modulated radiation therapy in patients with intermediate- or high-risk prostate cancer. METHODS: We conducted a review of the data, retrieved from our institutional database, of patients who had received intensity-modulated radiation therapy for localized prostate cancer at a radiation dose of 78 Gy in 39 fractions. Data of 201 patients with intermediate-risk prostate cancer and 311 patients with high-risk prostate cancer were analyzed. RESULTS: The median follow-up period after the completion of intensity-modulated radiation therapy was 100 months (range, 24-154). The rates of cause-specific survival, overall survival, metastasis-free survival and biochemical recurrence-free survival in the intermediate-risk patients were 99, 95, 95 and 94% at 5 years and 99, 91, 90 and 86% at 8 years, respectively; the corresponding rates in the high-risk patients were 100, 97, 91 and 84% at 5 years and 96, 92, 84 and 76% at 8 years, respectively. The crude incidence of late grade 2-3 genitourinary toxicity was 28.1%, and that of late grade 3 genitourinary toxicity was 2.0%. The crude incidence of late grade 2 gastrointestinal toxicity was 5.1%, and there were no cases of late grade 3 gastrointestinal toxicity. CONCLUSIONS: Our data demonstrated that intensity-modulated radiation therapy is effective for patients with localized intermediate-risk or high-risk prostate cancer while having minimal toxicity.

Dose-Based Radiomic Analysis (Dosiomics) for Intensity Modulated Radiation Therapy in Patients With Prostate Cancer: Correlation Between Planned Dose Distribution and Biochemical Failure.

PURPOSE: Although radiation therapy is one of the most significant treatment modalities for localized prostate cancer, the prognostic factors for biochemical recurrence (BCR) regarding the treatment plan are unclear. We aimed to develop a novel dosiomics-based prediction model for BCR in patients with prostate cancer and clarify the correlations between the dosimetric factors and BCR. METHODS AND MATERIALS: This study included 489 patients with localized prostate cancer (BCR: 96; no-BCR: 393) who received intensity modulated radiation therapy. A total of 2475 dosiomic features were extracted from the dose distributions on the prostate, clinical target volume (CTV), and planning target volume. A prediction model for BCR was trained on a training cohort of 342 patients. The performance of this model was validated using the concordance index (C-index) in a validation cohort of 147 patients. Another model was constructed using clinical variables, dosimetric parameters, and radiomic features for comparisons. Kaplan-Meier curves with log-rank analysis were used to assess the univariate discrimination based on the predictive dosiomic features. RESULTS: The dosiomic feature derived from the CTV was significantly associated with BCR (hazard ratio, 0.73; 95% CI, 0.57-0.93; P = .01). Although the dosiomics model outperformed the dosimetric and radiomics models, it did not outperform the clinical model. The performance significantly improved by combining the clinical variables and dosiomic features (C-index: 0.67; 95% CI, 0.65-0.68; P < .0001). The predictive dosiomic features were used to distinguish high-risk and low-risk patients (P < .05). CONCLUSIONS: The dosiomic feature extracted from the CTV was significantly correlated with BCR in patients with prostate cancer, and the dosiomics model outperformed the model with conventional dose indices. Hence, new metrics for evaluating the quality of a treatment plan are warranted. Moreover, further research should be conducted to determine whether dosiomics can be incorporated in a clinical workflow or clinical trial.

Comparison Between Dose-Escalated Intensity Modulated Radiation Therapy and 3-Dimensional Conformal Radiation Therapy for Salvage Radiation Therapy After Prostatectomy.

PURPOSE: To compare long-term outcomes and late toxicity between patients treated with 3-dimensional conformal radiation therapy (3D-CRT) and with dose-escalated intensity modulated radiation therapy (IMRT) as salvage radiation therapy (SRT) after prostatectomy. METHODS AND MATERIALS: A total of 110 patients who had been treated at our institution between 2010 and 2018 with SRT for biochemical recurrence after radical prostatectomy were included. The patients were treated either by 3D-CRT with 64 Gy (59 patients) or by IMRT with 70 Gy (51 patients). The irradiation target was the prostate bed only (106 patients) or the prostate bed and pelvic region (4 patients). Twelve patients (11%) received concurrent androgen deprivation therapy. The differences in clinical outcomes and late gastrointestinal (GI) and genitourinary (GU) toxicity between the 3D-CRT and IMRT groups were retrospectively assessed. Toxicities were recorded using the Common Terminology Criteria for Adverse Events, version 5.0. Prostate-specific antigen (PSA) progression after SRT was defined as an increase in the serum PSA level of 0.2 ng/mL from the PSA nadir after SRT and confirmed by a second PSA measurement that was higher than the first. RESULTS: The median follow-up time was 7.8 years for 3D-CRT (range:,0.3-9.2 years) and 3.1 years for IMRT (range, 0.4-7.2 years). There was no significant difference in the 4-year biochemical no-evidence-of-disease (bNED) rate between the 3D-CRT and IMRT groups (43.5% vs 52.1%; P = .20). Toxicity analysis showed no significant difference in late GI or GU toxicities of grade 2 or greater between the 3D-CRT and IMRT groups. The respective 4-year cumulative rates of toxicity in the 3D-CRT and IMRT groups were as follows: grade ≥2 GI toxicity, 8.8% and 4.4% (P = .42); grade ≥2 GU toxicity, 19.1% and 20.3% (P = .93); and grade ≥2 hematuria, 5.3% and 8.0% (P = .67). In the 3D-CRT group, the 8-year cumulative rates of GI toxicity, GU toxicity, and hematuria of grade 2 or greater were 8.8%, 28.4%, and 12.6%, respectively. CONCLUSIONS: Dose-escalated IMRT showed no improvements in bNED or late toxicity compared with 3D-CRT. In addition, the results suggest that GU toxicity can occur after a long period (even after 6 years), whereas GI toxicity is seldom newly observed after 4 years.

Comparison of Physician-recorded Toxicities and Patient-reported Outcomes of Five Different Radiotherapy Methods for Prostate Cancer.

BACKGROUND/AIM: To compare five radiotherapy methods for prostate cancer. PATIENTS AND METHODS: During 2005-2018, the data of patients with non-metastatic prostate cancer were retrospectively analysed. Patients were treated with high-dose-rate brachytherapy (HDR-BT); low-dose-rate brachytherapy (LDR-BT); or external-beam radiotherapy (EBRT), including conventionally fractionated radiotherapy (CFRT), moderate-hypofractionated radiotherapy (MHRT), and ultra-hypofractionated radiotherapy (UHRT). RESULTS: In total, 496 patients (149, HDR-BT; 100, LDR-BT; 100, CFRT; 97, MHRT, and 50, UHRT) with a median follow-up of 4.3 years were enrolled. The incidence of grade ≥2 acute genitourinary toxicities was significantly lower with HDR-BT (p<0.001) than with any other radiotherapy. The cumulative incidence of late grade ≥2 genitourinary toxicities was the highest with UHRT and significantly higher (p=0.005) with UHRT than with HDR-BT. Higher symptom score peaks were noted 4 weeks after therapy for LDR-BT than for EBRT. CONCLUSION: Physician-recorded toxicities were slightly lower with HDR-BT and patient-reported outcomes tended to be worse with LDR-BT.

Modern Radiation Therapy for Extranodal Nasal-Type NK/T-cell Lymphoma: Risk-Adapted Therapy, Target Volume, and Dose Guidelines from the International Lymphoma Radiation Oncology Group.

In the multidisciplinary management of early-stage extranodal natural killer/T-cell lymphoma, nasal type (ENKTCL), with curative intent, radiation therapy is the most efficacious modality and is an essential component of a combined-modality regimen. In the past decade, utilization of upfront radiation therapy and non-anthracycline-based chemotherapy has improved treatment and prognosis. This guideline mainly addresses the heterogeneity of clinical features, principles of risk-adapted therapy, and the role and appropriate design of radiation therapy. Radiation therapy methods (including target volume definition, dose and delivery methods) are crucial for optimizing cure for patients with early-stage ENKTCL. The application of the principles of involved site radiation therapy in this lymphoma entity often leads to a more extended clinical target volume (CTV) than in other lymphoma types because it usually presents with primary tumor invasion, multifocal lesions, or extensive submucosal infiltration beyond the macroscopic disease. The CTV varies across different primary sites and is classified mainly into nasal, nonnasal upper aerodigestive tract (UADT), and extra-UADT entities. This review is a consensus of the International Lymphoma Radiation Oncology Group regarding the approach to radiation therapy, target-volume definition, optimal dose, and dose constraints in ENKTCL treatment.

Outcomes after reirradiation of spinal metastasis with stereotactic body radiation therapy (SBRT): a retrospective single institutional study.

This study was aimed at assessing the feasibility and toxicity of using stereotactic body radiation therapy (SBRT) for reirradiation of spinal metastatic tumors. We conducted a retrospective review, from our institutional database, of the data of patients who received reirradiation, with overlap of some prescribed isodose lines to the vertebra from the initial radiation therapy, between 2007 and 2019. We identified 40 patients with spinal metastatic tumors, of whom 2 had 2 metastatic vertebral lesions each, totaling up to 42 target lesions. The median dose to spinal cord at the initial radiation therapy was 30 Gy. SBRT based on the intensity-modulated radiation therapy (IMRT) technique was used for reirradiation to spare the spinal cord. All patients received a prescription dose of 25 Gy in 5 fractions to the planning target volume (PTV). Among the 40 cases who had pain, pain relief was obtained in 24 (60%) after reirradiation. Neurologic improvement was obtained in 8 of 15 cases (53%). The adverse events were evaluated using the Common Terminology Criteria for Adverse Events Version 5.0. Reirradiation was well-tolerated, with only 2 patients experiencing adverse events ≥grade 2 in severity, including 1 patient with grade 3 pain, and another patient with grade 3 spinal fracture. None of the patients developed radiation myelopathy. Our data demonstrated that reirradiation of spinal metastasis using SBRT provided effective pain relief and neurologic improvement, with minimal toxicity.

Prediction and prevention of central nervous system relapse in patients with extranodal natural killer/T-cell lymphoma.

Because non-anthracycline-based chemotherapy with l-asparaginase has improved survival outcomes in patients with extranodal natural killer/T-cell lymphoma (ENKTL), the incidence of central nerve system (CNS) relapse can be different when compared with that in previous reports. In this research, we sought to identify the incidence of and predictors for CNS relapse and to evaluate the necessity of CNS prophylaxis with intermediate-dose methotrexate (ID-MTX). The records of 399 patients in the training cohort and 253 patients in the validation cohort with ENKTL who received non-anthracycline-based chemotherapy were reviewed. Patients were divided into 2 groups according to whether the chemotherapy regimen included ID-MTX above 2 g/m2. A new central nervous system-prognostic index of natural killer (CNS-PINK) model was developed using 1-point powerful predictors of CNS relapse (PINK; hazard ratio [HR], 2.908; P = .030 and extranodal involvement [≥2]; HR, 4.161; P = .001) and was calculated as a sum of scores. The high-risk group of CNS-PINK was defined as 2 points. The cumulative incidence of CNS relapse was different between the CNS-PINK risk groups in the training (P < .001) and validation (P = .038) cohorts. Patients in the high-risk CNS-PINK group who were treated with SMILE or SMILE-like regimens with ID-MTX (S-ID-MTX) displayed a lower incidence rate of CNS relapse than did those who received other regimens without ID-MTX in the training cohort (P = .029). The CNS-PINK was demonstrated its strong predictability of CNS relapse in ENKTL patients. The effectiveness of S-ID-MTX in preventing CNS events in high-risk CNS-PINK patients should be verified in future studies.

Fully automated dose prediction using generative adversarial networks in prostate cancer patients.

PURPOSE: Although dose prediction for intensity modulated radiation therapy (IMRT) has been accomplished by a deep learning approach, delineation of some structures is needed for the prediction. We sought to develop a fully automated dose-generation framework for IMRT of prostate cancer by entering the patient CT datasets without the contour information into a generative adversarial network (GAN) and to compare its prediction performance to a conventional prediction model trained from patient contours. METHODS: We propose a synthetic approach to translate patient CT datasets into a dose distribution for IMRT. The framework requires only paired-images, i.e., patient CT images and corresponding RT-doses. The model was trained from 81 IMRT plans of prostate cancer patients, and then produced the dose distribution for 9 test cases. To compare its prediction performance to that of another trained model, we created a model trained from structure images. Dosimetric parameters for the planning target volume (PTV) and organs at risk (OARs) were calculated from the generated and original dose distributions, and mean differences of dosimetric parameters were compared between the CT-based model and the structure-based model. RESULTS: The mean differences of all dosimetric parameters except for D98% and D95% for PTV were within approximately 2% and 3% of the prescription dose for OARs in the CT-based model, while the differences in the structure-based model were within approximately 1% for PTV and approximately 2% for OARs, with a mean prediction time of 5 seconds per patient. CONCLUSIONS: Accurate and rapid dose prediction was achieved by the learning of patient CT datasets by a GAN-based framework. The CT-based dose prediction could reduce the time required for both the iterative optimization process and the structure contouring, allowing physicians and dosimetrists to focus their expertise on more challenging cases.

Influence of chemoradiotherapy on nutritional status in locally advanced rectal cancer: Prospective multicenter study.

OBJECTIVE: The aim of this study was to investigate the influence of chemoradiotherapy (CRT) on nutritional status and the association between changes in nutritional status and clinical outcomes (treatment completion, adverse events, perioperative complications, and relapse-free survival [RFS]) in patients with locally advanced rectal cancer (LARC). METHODS: In this multicenter, phase II study, 41 patients with LARC underwent CRT for 5 wk, followed by a 6- to 8-wk interval before surgery. Body weight, body mass index (BMI), lean body mass, serum albumin, and prealbumin levels were measured before (pre-), during, and after CRT, and before surgery. Changes in these data and scores on the Malnutrition Universal Screening Tool (MUST) were calculated based on pre-CRT status. RESULTS: Twelve patients (29.3%) experienced body weight loss (BWL) ≥5% (defined as malnutrition) after CRT (P < 0.001) and before surgery (P = 0.035). Significant changes were seen in serum albumin levels and BMI during and after CRT (P < 0.001), and in MUST scores after CRT (P = 0.003) and before surgery (P = 0.035). Treatment completion was significantly associated with BWL (P = 0.028), MUST score (P = 0.013), and decreased serum albumin level (P = 0.001) after CRT. Regarding adverse events, MUST score before surgery (P = 0.009) and serum albumin level after CRT (P = 0.002) were significantly associated with diarrhea severity. Serum albumin level during CRT was associated with the onset of neutropenia (P = 0.005). No association was found between BWL and RFS. CONCLUSIONS: These findings suggest that malnutrition and changes in nutritional status are not only commonly observed after CRT, but also associated with treatment completion and adverse events.

Outcomes analysis of pre-brachytherapy MRI in patients with locally advanced cervical cancer.

INTRODUCTION: Various brachytherapy options are available for treating cervical cancer. This study investigated whether pre-brachytherapy magnetic resonance imaging (MRI) findings could help identify the appropriate brachytherapy technique for cervical cancer. METHODS: We retrospectively evaluated patients with cervical cancer who underwent pre-brachytherapy MRI within 7 days before their first high-dose rate brachytherapy treatment between December 2009 and September 2015. Patients who could not undergo MRI at pre-treatment and/or pre-brachytherapy and complete radical radiotherapy were excluded. Conventional intracavitary brachytherapy was the preferred treatment for ≤4 cm and symmetrical tumors. Non-conventional intracavitary brachytherapy, including interstitial brachytherapy, was the preferred treatment for bulky tumors, asymmetrical tumors, tumors with severe vaginal invasion, or bulky barrel-shaped tumors. The 3-year rates of overall survival, disease-free survival, and local control were compared using the Kaplan-Meier method and the log-rank test. Overall survival and local control rates were assessed using Cox regression analysis to identify risk factors for poor overall survival and local control outcomes. RESULTS: A total of 146 patients were included in the study. The median tumor sizes were 52 mm (range 17-85) at the pre-treatment MRI and 30 mm (range 0-78) at the pre-brachytherapy MRI. Six patients had International Federation of Gynecology and Obstetrics (FIGO) stage IB2, 67 patients had stage II, 64 patients had stage III, and nine patients had stage IVA disease. A total of 124 (85%) patients had squamous cell carcinoma and 22 (15%) patients had adenosquamous cell carcinoma or adenocarcinoma. The MRI findings showed severe vaginal invasion (pre-treatment: 19 patients, pre-brachytherapy: 10 patients), asymmetrical bulky tumors (pre-treatment: 28 patients, pre-brachytherapy: 16 patients), and severe corpus invasion (pre-treatment: 39 patients, pre-brachytherapy: 18 patients). Based on the pre-brachytherapy MRI findings, non-conventional intracavitary brachytherapy was administered to 34 (23.3%) patients. Brachytherapy seemed to be appropriate for 133 (91.1%) patients and inappropriate for 13 (8.9%) patients. The 3-year rates were 84.2% for overall survival and 90.1% for local control. Grade 3 late rectal complications occurred in two (1%) patients. Multivariate analysis showed that tumor characteristics (size, shape, and extent of invasion) were not risk factors, although inappropriate brachytherapy was significantly related to poor local control (p<0.001). CONCLUSION: Pre-brachytherapy MRI may help to select appropriate brachytherapy for cervical cancer and reduce the likelihood of inappropriate brachytherapy leading to poor local control.

Efficacy of radiation boost after breast-conserving surgery for breast cancer with focally positive, tumor-exposed margins.

Many patients with positive margins following breast-conserving surgery (BCS) undergo re-excisions that aim to remove residual disease from the breast, which brings a tremendous emotional burden in addition to financial consequences. We sought to determine whether re-excisions could be safely avoided without compromising local control and survival by using whole-breast radiation therapy (WBRT) with a tumor bed boost in patients with early-stage breast cancer with focally positive, tumor-exposed margins after BCS. All patients with ductal carcinoma in situ (DCIS) and/or invasive breast cancer (IBC) who had pathologically tumor-exposed margins following BCS, without re-excision and treated with WBRT with tumor bed boost between March 2005 and December 2011, were included. The radiotherapy consisted of WBRT at a dose of 50 Gy in 25 fractions, followed by a tumor bed boost with an additional dose of 16 Gy in eight fractions. A total of 125 patients fulfilled the eligibility criteria; of the 125 patients, 1 had bilateral breast cancer, resulting in 126 cases. Invasive disease was found in 102 (81%) cases and purely ductal carcinoma in situ (DCIS) disease in 24 (19%) cases. The 10-year ipsilateral breast tumor recurrence (IBTR) -free survival, progression-free survival (PFS), and 10-year overall survival (OS) rates were 95%, 92.5% and 96%, respectively. Patients with early-stage breast cancer who receive BCS and have focally positive, tumor-exposed margins can avoid re-excision by undergoing WBRT followed by a sufficient dose of tumor bed boost, without negatively impacting local control and survival.

Selection Criteria and Clinical Outcomes of Patients With Asymmetrical Cervical Cancer Treated With Various High-dose-rate Brachytherapy Techniques.

BACKGROUND/AIM: We aimed to evaluate the efficacy of high-dose-rate brachytherapy techniques selected according to pre-brachytherapy magnetic resonance imaging (MRI) findings in asymmetrical cervical cancer (ACC). PATIENTS AND METHODS: We analyzed 33 ACC patients. Asymmetric tumors were defined as those in which the difference between the distance from the cervical canal to the farthest end of the tumor [long distance (LD)] and the distance from the cervical canal to the contralateral tumor edge [short distance (SD)] is equal to or greater than 2 cm on the basis of MRI prior to treatment. On pre-treatment and pre-brachytherapy MRI, the median LDs were 40 mm and 21 mm, respectively. Patients with LD≥2 cm and LD - SD≥1 cm on pre-brachytherapy MRI received non-conventional intracavitary brachytherapy (ICBT). RESULTS: Sixteen patients (48%) received non-conventional ICBT. There was no significant difference in 3-year local control between the two treatment groups (100% vs. 81.2%, p=0.07); two patients had grade 2 radiation proctitis. CONCLUSION: Brachytherapy techniques selected according to pre-brachytherapy MRI findings were effective for ACC treatment.