Risk of thoracic soft tissue sarcoma after breast cancer radiotherapy: a population-based cohort study in Osaka, Japan

Postoperative radiotherapy for breast cancer reportedly increases the risk of thoracic soft tissue sarcomas, particularly angiosarcomas; however, the risk in the Japanese population remains unknown. Therefore, this study aimed to investigate the incidence of thoracic soft tissue sarcoma among patients with breast cancer in Japan and determine its association with radiotherapy. This retrospective cohort study used data from the population-based cancer registry of the Osaka Prefecture. The inclusion criteria were female sex, age 20-84 years, diagnosis of breast cancer between 1990 and 2010, no supraclavicular lymph node or distant metastasis, underwent surgery and survived for at least 1 year. The primary outcome was the occurrence of thoracic soft tissue sarcomas 1 year or later after breast cancer diagnosis. Among the 13 762 patients who received radiotherapy, 15 developed thoracic soft tissue sarcomas (nine angiosarcomas and six other sarcomas), with a median time of 7.7 years (interquartile range, 4.0-8.6 years) after breast cancer diagnosis. Among the 27 658 patients who did not receive radiotherapy, four developed thoracic soft tissue sarcomas (three angiosarcomas and one other sarcoma), with a median time of 11.6 years after diagnosis. The 10-year cumulative incidence was higher in the radiotherapy cohort than in the non-radiotherapy cohort (0.087 vs. 0.0036%, P < 0.001). Poisson regression analysis revealed that radiotherapy increased the risk of thoracic soft tissue sarcoma (relative risk, 6.8; 95% confidence interval, 2.4-24.4). Thus, although rare, breast cancer radiotherapy is associated with an increased risk of thoracic soft tissue sarcoma in the Japanese population.

Outcomes in patients with high- and very high-risk localized prostate cancer treated with definitive IMRT and long-term hormone therapy

BACKGROUND

The aim of this study was to evaluate the effectiveness of intensity-modulated radiation therapy in combination with long-term androgen deprivation therapy for high-risk and very high-risk localized prostate cancer while also investigating factors associated with the therapeutic effect.

METHODS

Men who fulfilled criteria for the National Comprehensive Cancer Network high-risk or very high-risk localized prostate cancer and were treated with definitive intensity-modulated radiation therapy (74-78 Gy) of the prostate and the seminal vesicle combined with androgen deprivation therapy in our institution from 2007 to 2016 were identified (n = 197). In principle, patients received androgen deprivation therapy for 3-6 months before radiation, concurrently, and for 2 years after completion of intensity-modulated radiation therapy.

RESULTS

The median follow-up period was 96 months. The 5-year and 10-year overall survival rates in the overall population were 96.9% and 89.3%, respectively. The 5-year and 10-year cumulative incidence rates of biochemical failure were 2.5% and 16.3% in the high-risk group, and 8.6% and 32.0% in the very high-risk group, respectively, indicating a significant difference between the two groups (P = 0.023). Grade Group 5 and younger age (cutoff: 70 years old) were independent predictors of recurrence (P = 0.016 and 0.017, respectively). Patients exhibiting biochemical failure within <18 months after completion of androgen deprivation therapy displayed an increased risk of cancer-specific mortality (P = 0.039) when contrasted with those who had a longer interval to biochemical failure.

CONCLUSIONS

Patients with the National Comprehensive Cancer Network very high-risk prostate cancer, particularly those with Grade Group 5 and younger age, showed worse outcomes following intensity-modulated radiation therapy and long-term androgen deprivation therapy.

Impact of magnetic resonance imaging-related geometric distortion of dose distribution in fractionated stereotactic radiotherapy in patients with brain metastases

PURPOSE

The geometric distortion related to magnetic resonance (MR) imaging in a diagnostic radiology (MRDR) and radiotherapy (MRRT) setup is evaluated, and the dosimetric impact of MR distortion on fractionated stereotactic radiotherapy (FSRT) in patients with brain metastases is simulated.

MATERIALS AND METHODS

An anthropomorphic skull phantom was scanned using a 1.5‑T MR scanner, and the magnitude of MR distortion was calculated with (MRDR-DC and MRRT-DC) and without (MRDR-nDC and MRRT-nDC) distortion-correction algorithms. Automated noncoplanar volumetric modulated arc therapy (HyperArc, HA; Varian Medical Systems, Palo Alto, CA, USA) plans were generated for 53 patients with 186 brain metastases. The MR distortion at each gross tumor volume (GTV) was calculated using the distance between the center of the GTV and the MR image isocenter (MIC) and the quadratic regression curve derived from the phantom study (MRRT-DC and MRRT-nDC). Subsequently, the radiation isocenter of the HA plans was shifted according to the MR distortion at each GTV (HADC and HAnDC).

RESULTS

The median MR distortions were approximately 0.1 mm when the distance from the MIC was < 30 mm, whereas the median distortion varied widely when the distance was > 60 mm (0.23, 0.47, 0.37, and 0.57 mm in MRDR-DC, MRDR-nDC, MRRT-DC, and MRRT-nDC, respectively). The dose to the 98% of the GTV volume (D98%) decreased as the distance from the MIC increased. In the HADC plans, the relative dose difference of D98% was less than 5% when the GTV was located within 70 mm from the MIC, whereas the underdose of GTV exceeded 5% when it was 48 mm (-26.5% at maximum) away from the MIC in the HAnDC plans.

CONCLUSION

Use of a distortion-correction algorithm in the studied MR diagnoses is essential, and the dosimetric impact of MR distortion is not negligible, particularly for tumors located far away from the MIC.

Dual-energy computed tomography-based iodine concentration as a predictor of histopathological response to preoperative chemoradiotherapy for pancreatic cancer

To explore predictors of the histopathological response to preoperative chemoradiotherapy (CRT) in patients with pancreatic cancer (PC) using dual-energy computed tomography-reconstructed images. This retrospective study divided 40 patients who had undergone preoperative CRT (50-60 Gy in 25 fractions) followed by surgical resection into two groups: the response group (Grades II, III and IV, evaluated from surgical specimens) and the nonresponse group (Grades Ia and Ib). The computed tomography number [in Hounsfield units (HUs)] and iodine concentration (IC) were measured at the locations of the aorta, PC and pancreatic parenchyma (PP) in the contrast-enhanced 4D dual-energy computed tomography images. Logistic regression analysis was performed to identify predictors of histopathological response. Univariate analysis did not reveal a significant relation between any parameter and patient characteristics or dosimetric parameters of the treatment plan. The HU and IC values in PP and the differences in HU and IC between the PP and PC (ΔHU and ΔIC, respectively) were significant predictors for distinguishing the response (n = 24) and nonresponse (n = 16) groups (P < 0.05). The IC in PP and ΔIC had a higher area under curve values [0.797 (95% confidence interval, 0.659-0.935) and 0.789 (0.650-0.928), respectively] than HU in PP and ΔHU [0.734 (0.580-0.889) and 0.721 (0.562-0.881), respectively]. The IC value could potentially be used for predicting the histopathological response in patients who have undergone preoperative CRT.

Improvement of target coverage using automated non-coplanar volumetric modulated arc therapy planning in stereotactic radiotherapy for cervical metastatic spinal tumors

This study aimed to compare dosimetric parameters for targets and organs at risk (OARs) between volumetric modulated arc therapy (VMAT) and automated VMAT (HyperArc, HA) plans in stereotactic radiotherapy for patients with cervical metastatic spine tumors. VMAT plans were generated for 11 metastases using the simultaneous integrated boost technique to deliver 35 to 40 and 20 to 25 Gy for high dose and elective dose planning target volume (PTVHD and PTVED), respectively. The HA plans were retrospectively generated using 1 coplanar and 2 noncoplanar arcs. Subsequently, the doses to the targets and OARs were compared. The HA plans provided significantly higher (p < 0.05) D_min (77.4 ± 13.1%), D_99% (89.3 ± 8.9%), and D_98% (92.5 ± 7.7%) for gross tumor volume (GTV) than those of the VMAT plans (73.4 ± 12.2%, 84.2 ± 9.6 and 87.3 ± 8.8% for D_min, D_99% and D_98%, respectively). In addition, D_99% and D_98% for PTVHD were significantly higher in the HA plans, whereas dosimetric parameters were comparable between the HA and VMAT plans for PTVED. The D_max values for the brachial plexus, esophagus, and spinal cord were comparable, and no significant difference was observed in the D_mean for the larynx, pharyngeal constrictor, thyroid, parotid grand (left and right), and Submandibular gland (left and right). The HA plans provided significantly higher target coverage of GTV and PTVHD, with a comparable dose for OARs with VMAT plans. The results of this study may contribute to the improvement of local control in clinical practice.

Linear accelerator-based stereotactic radiotherapy for brain metastases, including multiple and large lesions, carries a low incidence of acute toxicities: a retrospective analysis

BACKGROUND

Data on acute toxicities after stereotactic radiotherapy (SRT) for brain metastases, including multiple and large lesions, are lacking. We aimed to evaluate the incidence and nature of toxicities immediately after SRT using a linear accelerator.

METHODS

This retrospective study reviewed the medical records of 315 patients with brain metastases treated with SRT at our institution between May 2019 and February 2022. In total, 439 SRT sessions were performed for 2161 brain metastases. The outcome of interest was immediate side effects (ISEs), defined as new or worsening symptoms occurring during SRT or within 14 days after the end of SRT.

RESULTS

Grade ≥ 2 and ≥ 3 ISEs occurred in 16 (3.6%) and 7 (1.6%) cases, respectively. Among 63 treatments for 10 or more lesions (range: 10-40), 1 (1.6%) ISE occurred. Among 22 treatments for lesions with a maximum tumor volume of > 10 cc, 2 (9.1%) ISEs occurred. Grade ≥ 3 ISEs included 1, 4, 1, and 1 cases of grade 3 nausea, grade 3 new-onset partial and generalized seizures, grade 3 obstructive hydrocephalus, and grade 5 intracranial hemorrhage, respectively. ISEs were more common in patients with a larger maximum tumor volume, primary sites other than lung and breast cancer, and pre-treatment neurological symptoms.

CONCLUSION

SRT using a linear accelerator for brain metastases, including multiple and large lesions, is safe, with a low incidence of ISEs. Serious complications immediately after SRT are rare but possible; therefore, careful follow-up is necessary after treatment initiation.

Comparison of dosimetric parameters and robustness for rotational errors in fractionated stereotactic irradiation using automated noncoplanar volumetric modulated arc therapy for patients with brain metastases: single- versus multi-isocentric technique

To compare the dosimetric parameters of automated noncoplanar volumetric modulated arc therapy plans using single-isocentric (SIC) and multi-isocentric (MIC) techniques for patients with two brain metastases (BMs) in stereotactic irradiation and to evaluate the robustness of rotational errors. The SIC and MIC plans were retrospectively generated (35 Gy/five fractions) for 58 patients. Subsequently, a receiver operating characteristic curve analysis between the tumor surface distance (TSD) and V_25Gy was performed to determine the thresholds for the brain tissue. The SIC and MIC plans were recalculated based on the rotational images to evaluate the dosimetric impact of rotational error. The MIC plans showed better brain tissue sparing for TSD > 6.6 cm. The SIC plans provided a significantly better conformity index for TSD ≤ 6.6 cm, while significantly lower gradient index was obtained (3.22 ± 0.56vs. 3.30 ± 0.57, p < 0.05) in the MIC plans with TSD > 6.6 cm. For organs at risk (OARs) (brainstem, chiasm, lens, optic nerves, and retinas), D_0.1 cc was significantly lower (p < 0.05) in the MIC plans than in the SIC plans. The prescription dose could be delivered (D_99%) to the gross tumor volume (GTV) for patients with TSD ≤ 6.6 cm when the rotational error was < 1°, whereas 31% of the D_99% of GTV fell below the prescription dose with TSD > 6.6 cm. MIC plans can be an optimal approach for reducing doses to OARs and providing robustness against rotational errors in BMs with TSD > 6.6 cm.

Volumetric reduction of brain metastases after stereotactic radiotherapy: Prognostic factors and effect on local control

BACKGROUND AND PURPOSE

Few reports include volumetric measurements as endpoints after stereotactic radiotherapy (SRT) despite the importance of such measurements. This study aimed to (1) investigate the impact of the volumetric response (specifically, an over 65% and over 90% volume reduction in brain metastases) at 6 months post-SRT on local control and (2) identify the predictive factors for a volumetric response of over 65% and over 90%.

MATERIALS AND METHODS

This study included 250 unresected brain metastases (>0.3 cc) treated with SRT. Doses were stratified according to the biological effective dose (BED). The BED was calculated using four models: linear-quadratic (LQ): α/β = 10; LQ: α/β = 20; LQ cubic: α/β = 12; and LQ linear: α/β = 10. The median prescription dose was 30 Gy/3 fractions (BED20, 45). The median follow-up time after SRT was 18.6 months (range, 6.4-81.8 months).

RESULTS

In the multivariate analysis, over 65% volume reduction and over 90% volume reduction were prognostic factors for local control (hazard ratio: 2.370, p = 0.011 and hazard ratio: 3.161, p = 0.014, respectively). A dose of 80% of the gross tumor volume (GTV) D80 > BED20 58 was a predictive factor for over 65% and over 90% volume reductions (odds ratio: 1.975, p = 0.023; odds ratio: 3.204, p < 0.001, respectively).

CONCLUSION

Robust volume reduction of brain metastases at 6 months post-SRT can predict local control. GTV D80 in the LQ model: α/β = 20 may be warranted for good volume reduction.

Influence of radiation dose and predicted tumor invasion depth on local recurrence after definitive chemoradiotherapy for stage 0-I esophageal squamous cell carcinoma: a propensity score-weighted, retrospective, observational study

BACKGROUND

The optimal radiation dose for treating non-metastatic superficial esophageal squamous cell carcinoma is unknown. In this retrospective observational study, we investigated the influence of radiation dose and pretreatment endoscopic prediction of tumor invasion depth on local recurrence after definitive chemoradiotherapy in patients with superficial esophageal squamous cell carcinoma.

METHODS

We analyzed 134 patients with clinical Tis-T1N0M0 esophageal squamous cell carcinoma who underwent chemoradiotherapy at our institution between 2006 and 2019. Patients were grouped into standard-dose (50.0-50.4 Gy) and high-dose (60.0 Gy) radiotherapy groups. The outcomes of interest were local recurrence and major local recurrence (endoscopically unresectable local recurrent tumors). Kaplan-Meier analysis and the log-rank test were used with propensity score and inverse probability of treatment weighting. Cox proportional hazards analysis was performed to identify predictors of local recurrence and major local recurrence.

RESULTS

The median follow-up times were 52 and 84 months for the standard-dose and high-dose groups, respectively. The adjusted 3-year local recurrence and major local recurrence rates in the standard-dose and high-dose groups were 33.8 and 9.6% (adjusted hazard ratio, 4.00 [95% confidence interval: 1.64-9.73]; adjusted log-rank p = 0.001) and 12.5 and 4.7% (adjusted hazard ratio, 3.13 [95% confidence interval: 0.91-10.81]; adjusted log-rank p = 0.098), respectively. Cox proportional hazards analysis showed that standard-dose radiotherapy and endoscopic findings of deep submucosal invasion are independently associated with local recurrence and major local recurrence.

CONCLUSIONS

High-dose radiotherapy is more beneficial for local tumor control than standard-dose radiotherapy in patients with non-metastatic superficial esophageal squamous cell carcinoma. The use of high-dose radiotherapy may merit consideration for tumors with deep submucosal invasion.

Improvement in bladder volume reproducibility using A-mode portable ultrasound bladder scanner in moderate-hypofractionated volumetric modulated arc therapy for prostate cancer patients

Purpose

This study introduced an A‐mode portable ultrasound bladder scanner, the Lilium® α‐200 (here after Lilium; Lilium Otsuka, Kanagawa, Japan), for the treatment of prostate cancer patients with hypofractionated volumetric modulated arc therapy to improve the reproducibility of bladder volume (BV).

Materials and methods

Thirty patients were advised to maintain full BV prior to computed tomography (CT) simulation and daily treatment. Among these, the BV of 15 patients was measured using Lilium until a BV of 80% in the simulation was achieved (with the Lilium group). Daily cone‐beam CT (CBCT) was performed for treatment. The correlation between BV measured by CBCT and Lilium was assessed. The differences in the BV and dosimetric parameters of the bladder in the CBCT versus planning CT were compared between the groups with and without Lilium.

Results

There was a significantly strong relationship (r = 0.796, p < 0.05) between the BVs measured using CBCT and Lilium. The relative BV ratios to simulation CT < 0.5 and > 2 were observed in 10.3% and 12.7%, respectively, of treatment sessions without Lilium group, while these ratios were 1% and 2.8%, respectively, in the Lilium group. The mean absolute difference in the range of V_30Gy to V_40Gy without Lilium sessions was significantly larger (p < 0.05) than that in the Lilium group.

Conclusion

The use of the A‐mode portable ultrasound bladder scanner significantly improved the reproducibility of the BV, resulting in few variations in the dosimetric parameters for the bladder.

Intra‐fractional motion error during HyperArc stereotactic radiosurgery on patients with brain metastases: Comparison of open and full‐face clamshell‐style immobilization devices

Purpose

To compare the intrafractional motion error (IME) during stereotactic irradiation (STI) in patients with brain metastases immobilized using open‐ (Encompass) and full‐face (DSPS) clamshell‐style immobilization devices.

Methods

Encompass (38 patients) and DSPS (38 patients) were used for patient immobilization, and HyperArc plans with three to four non‐coplanar beams were generated to deliver 25 to 35 Gy in three to five fractions. Cone‐beam computed tomography (CBCT) was performed on patients before and after the treatment. Moreover, the difference in patient position between the two CBCT images was considered as the IME. The margins to compensate for IME were calculated using the van Herk margin formula.

Results

For Encompass, the mean values of IME in the translational setup were 0.1, 0.2, and 0.0 mm in the anterior–posterior, superior–inferior, and left–right directions, respectively, and the mean values of IME about rotational axes were −0.1, 0.0, and 0.0° for the Pitch, Roll, and Yaw rotations, respectively. For DSPS, the mean values of IME in the translational setup were 0.2, 0.2, and 0.0 mm in the anterior–posterior, superior–inferior, and left–right directions, respectively, and the mean values of IME about rotational axes were −0.1, −0.1, and 0.0° for the Pitch, Roll, and Yaw rotations, respectively. No statistically significant difference was observed between the IME of the two immobilization systems except in the anterior–posterior direction (p = 0.02). Moreover, no statistically significant correlation was observed between three‐dimensional IME and treatment time. The margin compensation for IME was less than 1 mm for both immobilization devices.

Conclusions

The IME during STI using open‐ and full‐face clamshell‐style immobilization devices is approximately equal considering the adequate accuracy in patient positioning.

Dose Reduction and Low-Contrast Detectability Using Iterative CBCT Reconstruction Algorithm for Radiotherapy

Introduction: Several studies have reported the relation between the imaging dose and secondary cancer risk and have emphasized the need to minimize the additional imaging dose as low as reasonably achievable. The iterative cone-beam computed tomography (iCBCT) algorithm can improve the image quality by utilizing scatter correction and statistical reconstruction. We investigate the use of a novel iCBCT reconstruction algorithm to reduce the patient dose while maintaining low-contrast detectability and registration accuracy. Methods: Catphan and anthropomorphic phantoms were analyzed. All CBCT images were acquired with varying dose levels and reconstructed with a Feldkamp-Davis-Kress algorithm-based CBCT (FDK-CBCT) and iCBCT. The low-contrast detectability was subjectively assessed using a 9-point scale by 4 reviewers and objectively assessed using structure similarity index (SSIM). The soft tissue-based registration error was analyzed for each dose level and reconstruction technique. Results: The results of subjective low-contrast detectability found that the iCBCT acquired at two-thirds of a dose was superior to the FDK-CBCT acquired at a full dose (6.4 vs 5.4). Relative to FDK-CBCT acquired at full dose, SSIM was higher for iCBCT acquired at one-sixth dose in head and head and neck region while equivalent with iCBCT acquired at two-thirds dose in pelvis region. The soft tissue-based registration was 2.2 and 0.6 mm for FDK-CBCT and iCBCT, respectively. Conclusion: Use of iCBCT reconstruction algorithm can generally reduce the patient dose by approximately two-thirds compared to conventional reconstruction methods while maintaining low-contrast detectability and accuracy of registration.

Impact of Multileaf Collimator Width on Dose Distribution in HyperArc Fractionated Stereotactic Irradiation for Multiple (-) Brain Metastases

BACKGROUND/AIM

To assess the impact of the width of multileaf collimator (MLC) on dose distributions on HyperArc fractionated stereotactic irradiation for multiple (5-10) brain metastases.

PATIENTS AND METHODS

Twenty-one HyperArc (HA) plans were generated using the high definition (HD) MLC (2.5 mm) to deliver 30-35 Gy in 3-5 fractions (HA-HD). The HyperArc plans using Millennium (ML) MLC (5 mm) were retrospectively generated (HA-ML) using the same planning parameters with HA-HD. Dosimetric parameters between the planning target volume (PTV) and organs at risk (OARs) were compared.

RESULTS

The conformity index was significantly higher (p<0.0001) in the HA-HD plans (0.95±0.04) than that in the HA-ML plans (0.92±0.06). The HA-HD provided significantly lower (p<0.0001) gradient index (5.6±2.5) than HA-ML (6.2±3.5). For the brainstem and retina (right), a statistically significant difference (p<0.05) was observed between the HA-HD (12.8±10.9 and 2.8±1.7 Gy, for brainstem and retina, respectively) and HA-ML (13.6±11.1 and 3.0±1.8 Gy) plans. For the brain tissue, the HA-HD plans statistically significantly reduced dosimetric parameters (p<0.0001) in all evaluated dose range (V_6Gy-V_28Gy).

CONCLUSION

The narrower MLC provided significantly higher conformity, steeper dose gradient, and better normal tissue sparing.

Prolonged overall treatment time negatively affects the outcomes of stereotactic body radiotherapy for early-stage non-small-cell lung cancer: A propensity score-weighted, single-center analysis

Previous studies have reported conflicting results for the effect of overall treatment time with stereotactic body radiotherapy on tumor control in early-stage non-small-cell lung cancer. To examine this effect, we conducted a propensity score-weighted, retrospective, observational study at a single institution. We analyzed the data of 200 patients with early-stage non-small-cell lung cancer who underwent stereotactic body radiotherapy (48 Gy in 4 fractions) at our institution between January 2007 and October 2013. Patients were grouped into consecutive (overall treatment time = 4–5 days, n = 116) or non-consecutive treatment groups (overall treatment time = 6–10 days, n = 84). The outcomes of interest were local control and overall survival. The Cox regression model was used with propensity score and inverse probability of treatment weighting. The median overall treatment times in the consecutive and non-consecutive groups were 4 and 6 days, respectively. The 5-year local control and overall survival rates in the consecutive vs. the non-consecutive group were 86.3 vs. 77.2% and 55.5 vs. 51.8%, respectively. After propensity score weighting, consecutive stereotactic body radiotherapy was associated with positive local control (adjusted hazard ratio 0.30, 95% confidence interval 0.14–0.65; p = 0.002) and overall survival (adjusted hazard ratio 0.56, 95% confidence interval 0.34–0.91; p = 0.019) benefits. The prolonged overall treatment time of stereotactic body radiotherapy treatment negatively affected the outcomes of patients with early-stage non-small-cell lung cancer. To our knowledge, this is the first study to show that in patients with early-stage non-small-cell lung cancer treated with the same dose-fractionation regimen, consecutive stereotactic body radiotherapy has a more beneficial effect on tumor control than non-consecutive stereotactic body radiotherapy.

Improvement of image quality for pancreatic cancer using deep learning-generated virtual monochromatic images: Comparison with single-energy computed tomography

PURPOSE

To construct a deep convolutional neural network that generates virtual monochromatic images (VMIs) from single-energy computed tomography (SECT) images for improved pancreatic cancer imaging quality.

MATERIALS AND METHODS

Fifty patients with pancreatic cancer underwent a dual-energy CT simulation and VMIs at 77 and 60 keV were reconstructed. A 2D deep densely connected convolutional neural network was modeled to learn the relationship between the VMIs at 77 (input) and 60 keV (ground-truth). Subsequently, VMIs were generated for 20 patients from SECT images using the trained deep learning model.

RESULTS

The contrast-to-noise ratio was significantly improved (p < 0.001) in the generated VMIs (4.1 ± 1.8) compared to the SECT images (2.8 ± 1.1). The mean overall image quality (4.1 ± 0.6) and tumor enhancement (3.6 ± 0.6) in the generated VMIs assessed on a five-point scale were significantly higher (p < 0.001) than that in the SECT images (3.2 ± 0.4 and 2.8 ± 0.4 for overall image quality and tumor enhancement, respectively).

CONCLUSIONS

The quality of the SECT image was significantly improved both objectively and subjectively using the proposed deep learning model for pancreatic tumors in radiotherapy.

Intra-fractional patient motion when using the Qfix Encompass immobilization system during HyperArc treatment of patients with brain metastases

Purpose

This study investigated the intra‐fractional motion (IM) of patients immobilized using the QFix Encompass Immobilization System during HyperArc (HA) treatment.

Method

HA treatment was performed on 89 patients immobilized using the Encompass. The IM during treatment (including megavoltage (MV) registration) was analyzed for six degrees of freedom including three axes of translation (anterior‐posterior, superior‐inferior (SI) and left‐right (LR)) and three axes of rotation (pitch, roll, and yaw). Then, the no corrected IM (IM_NC) was retrospectively simulated (excluding MV registration) in three directions (SI, LR, and yaw). Finally, the correlation between the treatment time and the IM of the 3D vector was assessed.

Results

The average IM in terms of the absolute displacement were 0.3 mm (SI), 0.3 mm (LR) and 0.2° (yaw) for Stereotactic radiosurgery (SRS), and 0.3 mm (SI), 0.2 mm (LR), and 0.2° (yaw) for stereotactic radiotherapy (SRT). The absolute maximum values of IM were <1 mm along the SI and LR axes and <1° along the yaw axis. The absolute maximum displacements for IM_NC were >1 mm along the SI and LR axes and >1° along the yaw axis. In the correlation between the treatment time and the IM, the r‐values were −0.025 and 0.027 for SRS and SRT respectively, along the axes of translation. For the axes of rotation, the r‐values were 0.012 and 0.206 for SRS and SRT, respectively.

Conclusion

Encompass provided patient immobilization with adequate accuracy during HA treatment. The absolute maximum displacement IM was less than IM_NC along the translational/rotational axes, and no statistically significant relationship between the treatment time and the IM was observed.

Improvement of image quality and assessment of respiratory motion for hepatocellular carcinoma with portal vein tumor thrombosis using contrast-enhanced four-dimensional dual-energy computed tomography

To assess the objective and subjective image quality, and respiratory motion of hepatocellular carcinoma with portal vein tumor thrombosis (PVTT) using the contrast-enhanced four-dimensional dual-energy computed tomography (CE-4D-DECT). For twelve patients, the virtual monochromatic image (VMI) derived from the CE-4D-DECT with the highest contrast to noise ratio (CNR) was determined as the optimal VMI (O-VMI). To assess the objective and subjective image quality, the CNR and five-point score of the O-VMI were compared to those of the standard VMI at 77 keV (S-VMI). The respiratory motion of the PVTT and diaphragm was measured based on the exhale and inhale phase images. The VMI at 60 keV yielded the highest CNR (4.8 ± 1.4) which was significantly higher (p = 0.02) than that in the S-VMI (3.8 ± 1.2). The overall image quality (4.0 ± 0.6 vs 3.1 ± 0.5) and tumor conspicuity (3.8 ± 0.8 vs 2.8 ± 0.6) of the O-VMI determined by three radiation oncologists was significantly higher (p < 0.01) than that of the S-VMI. The diaphragm motion in the L-R (3.3 ± 2.5 vs 1.2 ± 1.1 mm), A-P (6.7 ± 4.0 vs 1.6 ± 1.3mm) and 3D (8.8 ± 3.5 vs 13.1 ± 4.9 mm) directions were significantly larger (p < 0.05) compared to the tumor motion. The improvement of objective and subjective image quality was achieved in the O-VMI. Because the respiratory motion of the diaphragm was larger than that of the PVTT, we need to be pay attention for localizing target in radiotherapy.

Intra-fractional patient setup error during fractionated intracranial stereotactic irradiation treatment of patients wearing medical masks: comparison with and without bite block during COVID-19 pandemic

The immobilization of patients with a bite block (BB) carries the risk of interpersonal infection, particularly in the context of pandemics such as COVID-19. Here, we compared the intra-fractional patient setup error (intra-SE) with and without a BB during fractionated intracranial stereotactic irradiation (STI). Fifteen patients with brain metastases were immobilized using a BB without a medical mask, while 15 patients were immobilized without using a BB and with a medical mask. The intra-SEs in six directions (anterior-posterior (AP), superior-inferior (SI), left-right (LR), pitch, roll, and yaw) were calculated by using cone-beam computed tomography images acquired before and after the treatments. We analyzed a total of 53 and 67 treatment sessions for the with- and without-BB groups, respectively. A comparable absolute mean translational and rotational intra-SE was observed (P > 0.05) in the AP (0.19 vs 0.23 mm with- and without-BB, respectively), SI (0.30 vs 0.29 mm), LR (0.20 vs 0.29 mm), pitch (0.18 vs 0.27°), roll (0.23 vs 0.23°) and yaw (0.27 vs 22°) directions. The resultant planning target volume (PTV) margin to compensate for intra-SE was <1 mm. No statistically significant correlation was observed between the intra-SE and treatment times. A PTV margin of <1 mm was achieved even when patients were immobilized without a BB during STI dose delivery.

Elective Nodal Irradiation for Non-small Cell Lung Cancer Complicated With Chronic Obstructive Pulmonary Disease Affects Immunotherapy Αfter Definitive Chemoradiotherapy

BACKGROUND/AIM

The aim of this retrospective study was to detect the frequency, reasons, and significant factors for not receiving immunotherapy after chemoradiotherapy in non-small cell lung cancer (NSCLC) patients.

PATIENTS AND METHODS

Thirty-four patients with NSCLC received definitive chemoradiotherapy. The endpoint of this study was receiving durvalumab within 45 days after chemoradiotherapy for NSCLC.

RESULTS

Twenty-five of 34 (73%) patients received immunotherapy within 45 days after chemoradiotherapy. The reasons for not receiving immunotherapy were radiation pneumonitis (50%), radiation esophagitis (10%), and four other reasons (40%). Univariate analysis showed that significant factors for not receiving immunotherapy were elective nodal irradiation (ENI)+ and chronic obstructive pulmonary disease (COPD)+. The rate of immunotherapy was 100% (17/17 cases) in the COPD- and ENI- group, and 16% (1/6 cases) in the COPD+ and ENI+ group.

CONCLUSION

ENI for NSCLC complicated with COPD decreased the rate of immunotherapy after definitive chemoradiotherapy.

Death unrelated to cancer and death from aspiration pneumonia after definitive radiotherapy for head and neck cancer

BACKGROUND AND PURPOSE

The incidence of hypopharyngeal and supraglottic cancer (HSC) is high in Japan. This study aimed to retrospectively identify risk factors for death unrelated to cancer and death from aspiration pneumonia after definitive radiotherapy (RT) for HSC.

MATERIALS AND METHODS

Overall, 391 patients who began definitive RT for HSC between 2006 and 2014 were identified from the Osaka International Cancer Institute electronic database. Among 391 patients, 33 had a history of surgery for esophageal cancer (EC) and 19 received simultaneous RT for synchronous EC. The cause of death was divided into 3 main categories: "cancer under study," "other malignancy," and "unrelated to cancer." Cox proportional hazard model was used to estimate the hazard ratio (HR).

RESULTS

The median follow-up for survivors was 8 (range 3.6-14.1) years. At the last follow-up, 202 patients died. Death from "cancer under study," "other malignancy," and "unrelated to cancer" occurred in 92 (45.5%), 55 (27.2%), and 55 (27.2%) patients, respectively. Twelve patients died from aspiration pneumonia. In multivariate analysis for death unrelated to cancer and death from aspiration pneumonia, history of surgery for EC (HR: 3.87, p < 0.001; HR: 6.84, p = 0.007, respectively) and simultaneous RT for synchronous EC (HR: 3.74, p = 0.006; HR: 16.37, p < 0.001, respectively) were significant risk factors.

CONCLUSION

The laryngeal preservation approach by RT for HSC patients with a history of surgery for EC and simultaneous RT for synchronous EC should be used with caution.

Determination of optimal virtual monochromatic energy level for target delineation of brain metastases in radiosurgery using dual-energy CT

OBJECTIVE

Determination of the optimal energy level of virtual monochromatic image (VMI) for brain metastases in contrast-enhanced dual-energy CT (DECT) for radiosurgery and assessment of the subjective and objective image quality of VMI at the optimal energy level.

METHODS

20 patients (total of 42 metastases) underwent contrast-enhanced DECT. Spectral image analysis of VMIs at energy levels ranging from 40 to 140 keV in 1 keV increments was performed to determine the optimal VMI (VMI_opt) as the one corresponding to the highest contrast-to-noise ratio (CNR) between brain parenchyma and the metastases. The objective and subjective values of VMI_opt were compared to those of the VMI with 120 kVp equivalent, defined as reference VMI (VMI_ref, 77 keV). The objective measurement parameters included mean HU value and SD of tumor and brain parenchyma, absolute lesion contrast (LC), and CNR. The subjective measurements included five-point scale assessment of "overall image quality" and "tumor delineation" by three radiation oncologists.

RESULTS

The VMI at 63 keV was defined as VMI_opt. The LC and CNR of VMI_opt were significantly (p < 0.01) higher than those of VMI_ref (LC: 37.4 HU vs 24.7 HU; CNR: 1.1 vs 0.8, respectively). Subjective analysis rated VMI_opt significantly (p < 0.01) superior to VMI_ref with respect to the overall image quality (3.2 vs 2.9, respectively) and tumor delineation (3.5 vs 2.9, respectively).

CONCLUSION

The VMI at 63 keV derived from contrast-enhanced DECT yielded the highest CNR and improved the objective and subjective image quality for radiosurgery, compared to VMI_ref.

ADVANCES IN KNOWLEDGE

This paper investigated for the first time the optimal energy level of VMI in DECT for brain metastases. The findings will lead to improvement in tumor visibility with optimal VMI and consequently supplement accuracy delineation of brain metastases.

Stereotactic body radiation therapy planning for liver tumors using functional images from dual-energy computed tomography

PURPOSE

This study aimed to generate a functional image of the liver using dual-energy computed tomography (DECT) and a functional-image-based stereotactic body radiation therapy plan to minimize the dose to the volume of the functional liver (V_fl).

MATERIAL AND METHODS

A normalized iodine density (NID) map was generated for fifteen patients with liver tumors. The volume of liver with an NID < 0.46 was defined as V_fl, and the ratio between V_fl and the total volume of the liver (FLR) was calculated. The relationship between the FLR and Fibrosis-4 (FIB-4) was assessed. For patients with 15% < FLR < 85%, functional volumetric modulated-arc therapy plans (F-VMAT) were retrospectively generated to preserve V_fl, and compared to the clinical plans (C-VMAT).

RESULTS

FLR showed a significantly strong correlation with FIB-4 (r = -0.71, p < 0.01). For ten generated F-VMAT plans, the dosimetric parameters of D_99%, D_50%, D_1% and the conformity index were comparable to those of the C-VMAT (p > 0.05). For V_fl, F-VMAT plans achieved lower V_5Gy (122.4 ± 31.7 vs 181.1 ± 57.3 cc), V_10Gy (44.4 ± 22.2 vs 98.2 ± 33.3 cc), V_15Gy (22.6 ± 20.3 vs 49.8 ± 33.7 cc), V_20Gy (11.6 ± 14.1 vs 24.9 ± 25.1 cc), and D_mean (3.9 ± 2.3 vs 5.8 ± 3.0 Gy) values than the C-VMAT plans (p < 0.01).

CONCLUSIONS

The functional image derived from DECT was successfully used, allowing for a reduction in the dose to the V_fl without compromising target coverage.

Volumetric modulated arc therapy treatment planning based on virtual monochromatic images for head and neck cancer: effect of the contrast-enhanced agent on dose distribution

Virtual monochromatic images (VMIs) at a lower energy level can improve image quality but the computed tomography (CT) number of iodine contained in the contrast‐enhanced agent is dramatically increased. We assessed the effect of the use of contrast‐enhanced agent on the dose distributions in volumetric modulated arc therapy (VMAT) planning for head and neck cancer (HNC). Based on the VMIs at 40 keV (VMI_40keV), 60 keV(VMI_60keV), and 77 keV (VMI_77keV) of a tissue characterization phantom, lookup tables (LUTs) were created. VMAT plans were generated for 15 HNC patients based on contrast‐enhanced‐ (CE‐) VMIs at 40‐, 60‐, and 77 keV using the corresponding LUTs, and the doses were recalculated based on the noncontrast‐enhanced‐ (nCE‐) VMIs. For all structures, the difference in CT numbers owing to the contrast‐enhanced agent was prominent as the energy level of the VMI decreased, and the mean differences in CT number between CE‐ and nCE‐VMI was the largest for the clinical target volume (CTV) (125.3, 55.9, and 33.1 HU for VMI_40keV, VMI_60keV, and VMI_77keV, respectively). The mean difference of the dosimetric parameters (D_99%, D_50%, D_1%, D_mean, and D_0.1cc) for CTV and OARs was <1% in the treatment plans based on all VMIs. The maximum difference was observed for CTV in VMI_40keV (2.4%), VMI_60keV (1.9%), and VMI_77keV (1.5%) plans. The effect of the contrast‐enhanced agent was larger in the VMAT plans based on the VMI at a lower energy level for HNC patients. This effect is not desirable in a treatment planning procedure.

Effect of a saline flush technique for head and neck imaging in dual-energy CT: improvement of image quality and perivenous artefact reduction using virtual monochromatic imaging

AIM

To evaluate the effect of the saline flush (SF) technique on the depiction of lesions and the reduction of perivenous artefacts in the head and neck region using dual-energy computed tomography (CT) with virtual monochromatic imaging (VMI).

MATERIALS AND METHODS

Fifty patients with head and neck cancer were divided into two groups: group A, without a SF and group B, with a 30-ml SF. All images were acquired using fast kilovolt-switching CT (Revolution HD, GE Healthcare, Milwaukee, WI, USA). Contrast-to-noise ratios (CNRs) of the lesions were calculated at VMI energy levels ranging from 40 to 80 keV. Subjective analysis of overall image quality, delineation of lesions, and perivenous artefacts was conducted by two reviewers at both VMI energy level 40 keV and the optimal energy level (which showed optimal CNR by objective analysis).

RESULTS

Optimal energy level was 63 keV for group A and 61 keV for group B. At VMI energy levels ranging from 40 to 80 keV, the CNR was higher for group B. The highest subjective overall image quality was shown for group B at the optimal energy level (subjective image quality mean value, 3.40). Subjective delineation of lesions was comparable. The perivenous artefact score was significantly higher for group B (2.44 versus 2.74 [p<0.05] at 40 keV, 3.20 versus 3.46 [p<0.05] at the optimal energy level).

CONCLUSION

The SF technique results in an improvement of lesion CNR and a reduction of perivenous artefacts in VMI using duel-energy CT, especially at 40 keV.

Failure patterns after adjuvant chemoradiotherapy following endoscopic resection for superficial esophageal squamous cell carcinoma

Background

This study evaluated the locations of lymph node recurrence and their association with irradiation fields used for radiotherapy after adjuvant chemoradiotherapy following endoscopic resection for superficial esophageal squamous cell carcinoma.

Methods

Medical records of 96 consecutive patients with superficial esophageal squamous cell carcinoma who underwent adjuvant chemoradiotherapy following endoscopic resection were reviewed. Computed tomography was used to identify whether nodal recurrences were within the elective nodal irradiation field. The cumulative incidence of recurrence was calculated, accounting for death as a competing risk. Univariate and multivariate analyses identified factors predicting nodal recurrence.

Results

The median follow‐up period was 61 months (range: 6‐137 months). Seven patients (7.3%) developed lymph node recurrence only; two patients (2.1%) developed nodal plus local recurrence. Six of the seven cases without local recurrence involved the elective nodal irradiation field, with five cases involving the recurrent nerve lymph nodes. The 5‐year cumulative incidence of lymph node recurrence was higher for T1b tumors with lymphovascular invasion than for T1a tumors with lymphovascular invasion (17.6% vs 6.2%, P = 0.086; HR: 3.74, 95% CI: 0.80‐17.52, P = 0.094) and T1b tumors without lymphovascular invasion (17.6% vs 3.3%, P = 0.031; HR: 6.78, 95% CI: 0.80‐57.63, P = 0.080).

Conclusions

Lymph node recurrence frequently involved the elective nodal irradiation field, with recurrent nerve lymph nodes being common metastasis sites. The high incidence of nodal recurrence for T1b tumors with lymphovascular invasion highlights a need for new strategies for treating this subset of superficial esophageal squamous cell carcinomas.

Predictors of Acute Radiation Esophagitis in Non-small Cell Lung Cancer Patients Treated With Accelerated Hyperfractionated Chemoradiotherapy

BACKGROUND/AIM

To identify the clinical and dosimetric predictors of severe acute radiation esophagitis (RE) in patients with non-small cell lung cancer (NSCLC) treated with accelerated hyperfractionated concurrent chemoradiotherapy (AH-CCRT) with concomitant boost technique.

PATIENTS AND METHODS

A total of 159 patients who underwent AH-CCRT (64 Gy in 40 fractions twice daily) were retrospectively identified. Severe RE was designated as grade 3 or higher according to the Common Terminology Criteria for Adverse Events, version 4.0.

RESULTS

The incidence rate of grade 3 RE was 15.1% (24/159). The multivariate analysis that incorporated the Eastern Cooperative Oncology Group performance status (ECOG PS, ≥1 vs. 0) and the relative esophagus volume irradiated with at least 60 Gy (V₆₀) was optimal. Patients with a V₆₀ of ≥15% had a 37.8% risk of grade 3 RE compared to a 6.1% risk among those with a V₆₀ of <15%.

CONCLUSION

ECOG PS (≥1 vs. 0) and the V₆₀ were found to be significant risk factors for severe RE in NSCLC patients who underwent AH-CCRT.

Radiation Dose Escalation in Accelerated Hyperfractionated Radiotherapy for Stage III Non-small-cell Lung Cancer

AIM

To identify clinical benefits of dose escalation in accelerated hyperfractionated radiotherapy (AH-RT) for stage III non-small-cell lung cancer (NSCLC) using propensity score-matched (PSM) analysis.

MATERIALS AND METHODS

Our study retrospectively examined 294 patients undergoing definitive radiotherapy [131 patients, conventional once-daily radiotherapy (OD-RT); and 163, AH-RT] who were followed-up for a median of 40.4 months. The impact of overall survival (OS), progression-free survival (PFS), and locoregional control (LRC) was investigated.

RESULTS

Pre-PSM, the median OS, PFS, and LRC durations were 23.1 vs. 39.9 (p=0.03), 8.9 vs. 13.5 (p<0.01), and 12.9 vs. 50.3 (p<0.01) months in the OD-RT and AH-RT groups, respectively. After-PSM (two matched groups of 144 patients), AH-RT was associated with better LRC [adjusted hazard ratio (aHR)=0.59, 95% confidence interval (CI)=0.33-0.99, p=0.04] and marginally better PFS (aHR=0.65, 95% CI=0.41-1.03; p=0.06), but not OS (aHR=0.75, 95% CI=0.46-1.24; p=0.26).

CONCLUSION

After PSM analysis, dose escalation using AH-RT improved LRC and PFS in patients with locally advanced NSCLC. AH-RT can be a promising option for patients with advanced NSCLC.

How Well Does Dual-energy CT with Fast Kilovoltage Switching Quantify CT Number and Iodine and Calcium Concentrations?

RATIONALE AND OBJECTIVES

Because it is imperative for understanding the performance of dual-energy computed tomography scanner to determine clinical diagnosis, we aimed to assess the accuracy of quantitative measurements using dual-energy computed tomography with fast kilovoltage switching.

MATERIALS AND METHODS

Quantitative measurements were performed for 16 reference materials (physical density, 0.965-1.550 g/cm³; diameter of rod, 2.0-28.5 mm; iodine concentration, 2-15 mg/mL; and calcium concentration, 50-300 mg/mL) with varying scanning settings, and the measured values were compared to their theoretical values.

RESULTS

For high-density material, the maximum differences in Hounsfield unit values in the virtual monochromatic images at 50, 70, and 100 keV were -176.2, 61.0, and -35.2 HU, respectively, and the standard deviations over short- and long-term periods were 11.1, 6.1, and 3.5 HU at maximum. The accuracy of the Hounsfield unit measurement at 50 and 70 keV was significantly higher (P < 0.05) with higher radiation output and smaller phantom size. The difference in the iodine and calcium measurements in the large phantom were up to -2.6 and -60.4 mg/mL for iodine (5 mg/mL with 2-mm diameter) and calcium (300 mg/mL) materials, and the difference was improved with a small phantom. Metal artifact reduction software improved subjective image quality; however, the quantitative values were significantly underestimated (P < 0.05) (-49.5, -26.9, and -15.3 HU for 50, 70, and 100 keV, respectively; -1.0 and -17 mg/mL for iodine and calcium concentration, respectively) compared to that acquired without a metal material.

CONCLUSIONS

The accuracy of quantitative measurements can be affected by material density and the size of the object, radiation output, phantom size, and the presence of metal materials.

Efficacy and Safety of Endoscopic Resection Followed by Chemoradiotherapy for Superficial Esophageal Squamous Cell Carcinoma: A Retrospective Study

OBJECTIVES

The reported 1- and 3-year overall survival rates after esophagectomy for stage I superficial esophageal squamous cell carcinoma (SESCC) are 95-97% and 86%, and those after definitive chemoradiotherapy (CRT) are 98% and 89%, respectively. This study was performed to elucidate the efficacy and safety of another treatment option for SESCC: endoscopic resection (ER) followed by CRT.

METHODS

We retrospectively reviewed the overall survival, recurrence, and grade ≥3 adverse events of consecutive patients who refused esophagectomy and underwent ER followed by CRT for SESCC from 1 January 2006 to 31 December 2012.

RESULTS

In total, 66 patients with SESCC underwent ER followed by CRT during the study period, and complete follow-up data were available for all patients. The median age was 67 (range, 45-82) years, and the median observation period was 51 (range, 7-103) months. Local and metastatic recurrences occurred in 2 (3%) and 6 (9%) patients, respectively, and 17 (26%) patients died. The 1-, 3-, and 5-year overall survival rates were 98%, 87%, and 75%, respectively. One of the 23 patients with mucosal cancer and 5 of 43 with submucosal cancer developed metastatic recurrences (P=0.65). Five of the 61 patients with negative vertical resection margin and 1 of 5 with positive vertical resection margin developed metastatic recurrences (P=0.39). None of the 30 patients without lymphovascular involvement developed metastatic recurrences; however, 6 of 36 patients with lymphovascular involvement developed metastatic recurrences (P=0.0098). Grade ≥3 adverse events occurred in 21 (32%) patients and all adverse events were associated with CRT, hematological adverse events in 13 (20%), and non-hematological adverse events in 9 (14%).

CONCLUSIONS

ER followed by CRT provides survival comparable with that of esophagectomy or definitive CRT and has a low local recurrence rate. A particularly favorable outcome is expected for cancers without lymphovascular involvement.

Selective neck irradiation for supraglottic cancer: focus on Sublevel IIb omission

OBJECTIVE

To estimate selective neck irradiation omitting surgical Sublevel IIb.

METHODS

Bilateral necks of 47 patients (94 necks) were subjected to definitive radiotherapy for supraglottic cancer. Sixty-nine and 25 necks were clinically node negative (cN-) and clinically node positive (cN+), respectively. We subdivided Sublevel IIb by the international consensus guideline for radiotherapy into Sublevel IIb/a, directly posterior to the internal jugular vein, and Sublevel IIb/b, which was behind Sublevel IIb/a and coincided with surgical Sublevel IIb. Bilateral (Sub)levels IIa, III, IV and IIb/a were routinely irradiated, whereas Sublevel IIb/b was omitted from the elective clinical target volume in 73/94 treated necks (78%).

RESULTS

Two patients presented with ipsilateral Sublevel IIb/a metastases. No Sublevel IIb/b metastasis was observed. Five patients experienced cervical lymph node recurrence; Sublevel IIb/a recurrence developed in two patients, whereas no Sublevel IIb/b recurrence occurred even in the cN- necks of cN+ patients or cN0 patients. The 5-year regional control rates were 91.5% for Sublevel IIb/b-omitted patients and 77.8% for Sublevel IIb/b treated patients.

CONCLUSIONS

Selective neck irradiation omitting Sublevel IIb/b did not compromise regional control and could be indicated for cN- neck of supraglottic cancer.

Definitive radiotherapy for primary vaginal cancer: correlation between treatment patterns and recurrence rate

The purpose of this study was to determine the outcomes and optimal practice patterns of definitive radiotherapy for primary vaginal cancer. Between 1993 and 2012, 49 patients were treated with definitive radiotherapy for primary vaginal cancer in three hospitals. Of these, 15 patients (31%) had clinically positive regional lymph node metastasis. A total of 34 patients (70%) received external beam radiotherapy with high-dose-rate brachytherapy (interstitial or intracavitary), and 8 (16%) (with small superficial Stage I tumors) were treated with local radiotherapy. The median follow-up was 33 months (range: 1-169 months). The 3-year overall survival (OS), disease-free survival (DFS), and loco-regional control (LRC) rates were 83%, 59% and 71%, respectively. In multivariate analysis, the histological type (P = 0.044) was significant risk factors for LRC. In Federation of Gynecology and Obstetrics (FIGO) Stage I cases, 3 of 8 patients (38%) who did not undergo prophylactic lymph node irradiation had lymph node recurrence, compared with 2 of 12 patients (17%) who underwent prophylactic pelvic irradiation. For Stage III-IV tumors, the local recurrence rate was 50% and the lymph node recurrence rate was 40%. Patients with FIGO Stage I/II or clinical Stage N1 had a higher recurrence rate with treatment using a single modality compared with the recurrence rate using combined modalities. In conclusion, our treatment outcomes for vaginal cancer were acceptable, but external beam radiotherapy with brachytherapy (interstitial or intracavitary) was needed regardless of FIGO stage. Improvement of treatment outcomes in cases of FIGO Stage III or IV remains a significant challenge.

Transient ligation of umbilical vessels elevates placental tissue oxygen index (TOI) values measured by near-infrared spectroscopy (NIRS) in clawn miniature pig animal model

We recently found a significant elevation in placental tissue oxygen index (TOI) values in cases of fetal growth restriction using near-infrared spectroscopy (NIRS), indicating high oxygenation in the placental tissue. We hypothesized that insufficient fetoumbilical blood flow is causatively associated with high oxygenation levels in placental tissue. We transiently (for 15 sec) ligated the whole umbilicus, umbilical arteries, or veins of pregnant Clawn miniature pigs (102-113 days of gestation) and assessed the changes in TOI values of the placenta and fetus. The ligation significantly increased placental TOI values (p<0.01, respectively), but concomitantly decreased fetal TOI values (p<0.01, respectively), suggesting a decline in oxygen inflow from the maternal to fetal circulation in the placental tissue to be causative of the elevated placental TOI values. These observations suggest the promising clinical use of placental TOI values measured noninvasively by the transabdominal application of NIRS to assess the fetoplacental circulation.

Neonatal exposure to leptin reduces glucose tolerance in adult mice

AIM

The aim of this study was to evaluate the effect of leptin treatment in mouse neonates on glucose metabolism in adulthood.

METHODS

Leptin was administered subcutaneously to normally nourished neonates, from 5.5 to 10.5 days of age, to mimic the premature surge observed in neonates undernourished in utero. At 15-16 weeks of age, we measured blood glucose or insulin levels after the intraperitoneal administration of glucose or insulin.

RESULTS

After the intraperitoneal administration of glucose, the levels of blood glucose, but not insulin, in adult mice that received the neonatal leptin treatment were significantly higher than that of those which received vehicle control. After the intraperitoneal administration of insulin, the levels of blood glucose in adult mice that underwent neonatal leptin treatment were significantly higher than that of those which received vehicle control.

CONCLUSION

These findings suggest that the premature leptin surge plays an essential role, as a programming signal during the early neonatal period, as well as in the developmental origins of impaired insulin sensitivity.

Life-threatening hemorrhage and prolonged wound healing are remarkable phenotypes manifested by complete plasminogen activator inhibitor-1 deficiency in humans

BACKGROUND

 Plasminogen activator inhibitor-1 (PAI-1) is the primary physiological regulator of urokinase plasminogen activator (uPA) and tissue plasminogen activator (tPA) activity. A number of studies have shown that elevated levels of PAI-1 are related to pathological states such as an increased risk of arterial thrombotic events and a poor prognosis for cancer patients; however, there are few reports about PAI-1 deficiency in humans because the disorder is very rare.

OBJECTIVE

 To understand the in vivo impact of a complete PAI-1 deficiency, Serpine1(-/-) mice were generated; a number of in vivo studies have been conducted to elucidate the function of PAI-1 using Serpine1(-/-) mice. The phenotypes demonstrated in Serpine1(-/-) mice, however, were quite different from those in humans. Therefore, it is necessary to find out and analyze SERPINE1 deficiency in humans.

PATIENT AND METHODS

 The patient is a 47-year-old woman who has had multiple episodes of major bleeding. Although most of the patient's blood coagulation factors were functionally normal, her PAI-1 antigen levels were undetectable. Therefore, DNA sequencing of the SERPINE1 gene were analyzed.

RESULTS

 The proband had a homozygous 1-bp duplication (C) at exon 3 (c.356dupC; p.Ile120AspfsX42). Both wild-type PAI-1 (42.7 kDa) and mutated (Mut) PAI-1 (14.7kDa) were expressed in COS-1 cells, although the level of Mut PAI-1 expressed in the cell lysates was much lower. Wild-type PAI-1 was observed in the culture supernatant, whereas no Mut PAI-1 was detected in the supernatant.

CONCLUSIONS

 Considering the results of the present study, the translation of mouse studies to humans must be performed with great care.

A combination of subcuticular sutures and a drain for skin closure reduces wound complications in obese women undergoing surgery using vertical incisions

Obesity is a risk factor for surgical site or wound complications in women undergoing surgery involving vertical incisions. Several investigators have reported the efficacy of subcutaneous drains in minimising the complication rate but there is no consensus on using these for surgery in obese patients. In 2006, the Scottish Surveillance of Healthcare Associated Infection Programme showed that using subcuticular sutures rather than staples to close incisions significantly reduced the risk of surgical site infection. Before January 2008 (group 1; N = 40), wound complications occurred in some obese patients in our hospital after obstetric and gynaecological surgery when only staples were used for skin closure. In January 2008 (group 2; N = 31), we changed the method of skin closure for obese patients [body mass index (BMI) > 28 kg/m(2)] and we now use a subcutaneous drain with four channels along the running tube and subcuticular sutures with interrupted, buried 4-0 polydioxanone sutures. The aim of this study was to assess the effects of these interventions for skin closure in obese women. The general characteristics (age, weight and BMI) were similar between the two groups. There were no wound complications in group 2. In group 1, wound disruptions and a seroma occurred in five (12.5%) and one (2.5%) patients, respectively. The wound complication rate in group 2 was significantly lower than that in group 1 (P = 0.0319). Thus, new materials and techniques for skin closure can reduce the wound complication rate in obese women.