Incidence of Radiation-induced Nausea and Vomiting: A Prospective Single-institution Pilot Study

Radiation-induced nausea and vomiting (RINV) is a frequent adverse event that occurs in patients undergoing radiotherapy. However, research on RINV is underrepresented. This prospective single-institution exploratory pilot study investigated the incidence of RINV according to the irradiation site and observed the efficacy of symptomatic antiemetic treatment in controlling symptoms of RINV. The primary outcomes were the proportions of emesis-free days and nausea-free days. The secondary endpoints included the time to the first episode of RINV, frequency of vomiting, and severity of nausea, including its impact on eating habits and weight loss. Fifteen patients were enrolled in each group (minimal, low, and moderate emetogenic risk). All patients received greater than 20 Gy in five fractions. Evaluation was based on weekly questionnaires completed by patients during routine clinic visits. Nausea and vomiting occurred in 11 and 0 patients, respectively. Six of 15 patients in the minimal-risk group, 1 in the low-risk group, and 4 in the moderate-risk group experienced nausea. Although all 11 symptomatic patients were offered antiemetics, only 3 used them, who reported satisfactory control of nausea. The percentage of emesis-free days for all patients was 100% and the percentage of nausea-free days for the 11 patients who developed RINV was 38%. An unexpectedly high percentage of patients in the minimal-risk group experienced nausea; all had breast cancer. Future studies should investigate factors beyond the irradiation site, including the characteristics of the patient and the treatment, to better predict an individual's risk of RINV.

The impact of the COVID-19 pandemic on radiotherapy delivery in Japan: An observational study based on the national database

BACKGROUND

This study analyzed the impact of the coronavirus disease 2019 (COVID-19) pandemic on radiotherapy delivery in Japan using a high-quality Japanese national database based on universal health coverage.

METHODS

We performed a retrospective observational study using National Database of Health Insurance Claims and Specific Health Checkups of Japan open data focused on radiotherapy between fiscal year (FY) 2019 and FY2020 and the number of COVID-19 cases from the Ministry of Health, Labour, and Welfare. We statistically analyzed the relationship between the number of COVID-19 cases and the number of radiotherapy deliveries in Japan as a whole and by prefecture.

RESULTS

The total number of external beam radiotherapy (EBRT) fractions was 4,472,140 in FY2019 and 4,227,673 in FY2020 (-5.8%). EBRT courses were 250,395 in FY2019 and 240,329 in FY2020 (-4.0%), stereotactic radiotherapy courses were 27,619 in FY2019 and 31,786 in FY2020 (+15.1%), and single-fraction palliative radiotherapy courses were 4124 in FY2019 and 5255 in FY2020 (+21.5%). The total number of breast and prostate hypofractionated radiotherapy (HFRT) fractions was 155,773 and 48,188 in FY2019, and 200,256 and 84,230 in FY2020 (+28.6% and +74.8%), respectively. In the Pearson correlation analysis, EBRT fractions were lower, and breast HFRT fractions were higher in prefectures with more COVID-19 cases.

CONCLUSIONS

Overall, radiotherapy delivery in Japan was relatively stable after the pandemic, with an increase in HFRT. Also, EBRT fractions decreased, and breast HFRT were more likely to be used in prefectures with more COVID-19 cases.

Factors associated with quality of life in patients receiving palliative radiotherapy for bone metastases: a secondary cross-sectional analysis of data from a prospective multicenter observational study

OBJECTIVE

To identify factors significantly associated with quality of life (QOL) and determine if these associations are strong enough to predict certain aspects of QOL without measuring them.

METHODS

We conducted an exploratory secondary analysis of baseline data of 224 patients (enrolled between December 2020 and March 2021) from a previously published prospective observational study on radiotherapy for bone metastases at 26 centres. Using univariable linear regression, we assessed the association between patient/treatment factors and QOL scale scores as measured by the European Organization for Research and Treatment of Cancer (EORTC) QOL Questionnaire Core 15-Palliative (QLQ-C15-PAL) and the EORTC QOL Questionnaire Bone Metastases module (QLQ-BM22).

RESULTS

Age and sex were not significantly associated with QOL. Worse performance status, higher pain scores, and opioid and single-fraction use were significantly associated with most QOL scales; these four factors were associated with worse global QOL, worse functioning status, and more severe symptoms. The coefficients of determination for most QOL scales were less than 0.2, indicating that most of the variability in QOL scores was not explained by any of the explanatory variables.

CONCLUSION

Performance status, pain intensity, and opioid and single-fraction use were significantly associated with most QOL scales. However, the associations were not strong enough to estimate QOL.

ADVANCES IN KNOWLEDGE

To date, the association between treatment factors and QOL in patients with bone metastases has not been fully studied. We identified the factors that were significantly associated with QOL and found that these associations were not strong enough to predict QOL.

Comparison of the Efficacy of Low Dose Tadalafil with Tamsulosin against Lower Urinary Tract Symptoms and Sexual Dysfunction after Low Dose Rate Prostate Brachytherapy

PURPOSE/OBJECTIVE(S)

Patients with clinically localized prostate cancer (PCa) can be curatively treated with different modalities, including low dose rate (LDR) prostate brachytherapy (PB). LDR-PB allows the patient a relatively short recovery time compared with other treatment modalities such as prostatectomy. However, PB might exert distinct impact on quality of life, lower urinary tract symptoms (LUTS) and sexual dysfunction (SD) are two major concerns. The aim of present study was to assess prospectively the efficacy of low dose tadalafil treatment on both SD and LUTS compared with tamsulosin treatment in patients treated PB for localized PCa.

MATERIALS/METHODS

Patients scheduled for PB with I-125 seeds for low or intermediate-risk localized PCa at our institution were eligible for this study. The prescribed dose was set at 160 gray. Participants were randomized into two groups; those started treating with a daily use of 0.2 mg of tamsulosin hydrochloride or 5 mg of tadalafil just after PB. The duration of the study was 12 months and the patients were assessed for urinary and sexual function status at baseline, and 1, 3, 6, and 12 months after PB. The primary study endpoints were both changes from baseline in urinary and sexual function status.

RESULTS

Between July 2015 and August 2020, 120 participants were enrolled in this study. The median age was 68 years with the median PSA of 6.5 ng/ml. A total 15 patients were excluded within 6 months after randomization. All subjective LUTS findings, including International Prostate Symptom Score (IPSS), and Over Active Bladder Symptom Score (OABSS), were significantly deteriorated at 1, 3, and 6 months after PB compared with baseline in both groups, respectively (p<0.05). Among objective LUTS findings, a significant decrease in maximum urinary flow rate (Qmax) was found at 1, 3, 6, and 12 months after PB compared with baseline in both groups, respectively (p<0.05). A significant increase in post void residual urine (PVR) was found at 1, 3, and 6 months after PB compared to baseline in tadalafil group, whereas no significant increase was seen in tamsulosin group. There were no statistically significant differences between the 2 groups in scores of the total International Index of Erectile Function (IIEF)-15 and Erection Hardness Score (EHS) before and at 1 month post PB. The EHS was significantly higher in tadalafil group compared with tamsulosin group at 3, 6 and 12 months (p = 0.001, p = 0.004, and p = 0.019, respectively). The EHS after PB in tadalafil group was not significantly decreased from baseline.

CONCLUSION

After LDR-PB, tamsulosin treatment significantly decreased PVR compared with tadalafil. On the other hand, tadalafil contributed to maintain erection hardness compared with tamsulosin.

Phase I study of neoadjuvant S-1 plus cisplatin with concurrent radiation for biliary tract cancer (Tokyo Study Group for Biliary Cancer: TOSBIC02)

Aim

Neoadjuvant chemoradiotherapy may improve survival in patients with advanced cholangiocarcinoma. This Phase I study aimed to determine the recommended dose of neoadjuvant chemoradiotherapy and decide whether to move to a Phase II study.

Methods

Patients diagnosed with resectable stage II-IVa cholangiocarcinoma were administered cisplatin (40 [level 0], 50 [level 1 as starting dose], or 60 [level 2] mg/m2), 80 mg/m2 of S-1, and 50.4 Gy of external beam radiation. The recommended dose was defined as a dose one-step lower than the maximum-tolerated dose, which was defined when dose-limiting toxicity was observed in three or more of the six patients.

Results

Twelve patients were eligible from November 2012 to May 2016. Ten patients had perihilar cholangiocarcinoma and two patients had distal cholangiocarcinoma. Dose-limiting toxicity was observed in one of the first six patients at level 1 and two of the next six patients at level 2; thus, the maximum-tolerated dose was not determined even at level 2 and the recommended dose was determined as level 2. Four patients had partial response, four patients had stable disease, and two patients had progression of disease because of liver metastases. Finally, nine patients underwent radical surgery and seven cases achieved R0 resection. However, five cases suffered biliary leakage and one suffered intrahospital death due to rupture of the hepatic artery.

Conclusion

We determined the recommended dose of neoadjuvant chemoradiotherapy for resectable cholangiocarcinoma. However, we terminated the trial due to a high incidence of morbidity and unexpected mortality.

Dosimetric comparison of rectal dose-reductive techniques in intra-cavitary brachytherapy for cervical cancer: A retrospective analysis

Purpose

Rectal complications in radiotherapy for cervical cancer can highly affect quality of life and correlate with rectal dose. Vaginal gauze packing (VP) and rectal retraction (RR) are widely used for rectal dose reduction in high-dose-rate brachytherapy. We aimed to perform a dosimetric comparison of these two methods for three-dimensional image-guided adaptive brachytherapy.

Material and methods

We retrospectively examined 50 patients with cervical cancer treated with definitive radiotherapy, including intra-cavitary brachytherapy, performed with VP and RR. We extracted two fractions for each patient: one fraction with VP and the next fraction with RR, and then compared dose-volume parameters. In total, 50 fractions each were analyzed in VP and RR groups. Dose to 90% (D90) of high-risk clinical target volume (HR-CTV), and minimum dose to most exposed 2.0 cm3 of other organs at risk (D2cm3) for the rectum and bladder were determined from planning computed tomography.

Results

There were no significant differences between VP and RR in D90 of HR-CTV (mean: 7.479 Gy and 7.652 Gy, respectively, p = 0.172). The D2cm3 values for the rectum (mean: 4.234 Gy vs. 4.627 Gy, p = 0.008) and bladder (mean: 5.959 Gy vs. 6.690 Gy, p < 0.001) were significantly lower with VP compared with RR.

Conclusions

VP reduced the dose to the rectum and bladder when compared with RR without impairing the dose to CTV.

Evaluation of dose perturbations around iodine-125 seed sources in supplemental external beam prostate radiotherapy

We investigated dose perturbations caused by 125I seeds in patients undergoing supplemental external beam radiotherapy (EBRT) for prostate cancer. We examined two types of nonradioactive seed models: model 6711 and model STM1251. All experiments were performed using a water-equivalent phantom. Radiochromic film was used to measure the dose distributions adjacent to the seeds upstream and downstream of the external beam source. Single and clusters of multiple seeds were placed in slots in a solid water (SW) slab to measure dose perturbations with separate versus dense seed placement at beam energies of 6 or 10 MV. Monte Carlo simulations (MCSs) were also performed to include the theoretical basis against film dosimetry. Distinct patterns of dose enhancement (buildup [BU]) were upstream, and dose reduction (builddown [BD]) were downstream of the radiation source. Model 6711 with lower photon beam energies produced larger dose perturbations of BU and BD than the model STM1251. The results showed the same tendency with different seed placements and beam energies. However, these differences were not observed in the rotational irradiation measurement, which replicated a clinical plan. Dose perturbations around seeds result in dose enhancement and dose reduction with varying impact depending on the photon beam energy and seed type. This has the potential to cancel out these perturbations using multiple beam direction fields.

Income and Employment of Patients at the Start and in the Follow-up of Palliative Radiotherapy for Bone Metastasis

Purpose

The aim of this study was to understand the income and employment status of patients at the start of and during follow-up after palliative radiation therapy for bone metastasis.

Methods and Materials

From December 2020 to March 2021, a prospective multi-institutional observational study was conducted to investigate income and employment of patients at the start of administration of radiation therapy for bone metastasis and at 2 and 6 months after treatment. Of 333 patients referred to radiation therapy for bone metastasis, 101 were not registered, mainly because of their poor general condition, and another 8 were excluded from the follow-up analysis owing to ineligibility.

Results

In 224 patients analyzed, 108 had retired for reasons unrelated to cancer, 43 had retired for reasons related to cancer, 31 were taking leave, and 2 had lost their jobs at the time of registration. The number of patients who were in the working group was 40 (30 with no change in income and 10 with decreased income) at registration, 35 at 2 months, and 24 at 6 months. Younger patients (P = 0), patients with better performance status (P = 0), patients who were ambulatory (P = .008), and patients with lower scores on a numerical rating scale of pain (P = 0) were significantly more likely to be in the working group at registration. There were 9 patients who experienced improvements in their working status or income at least once in the follow-up after radiation therapy.

Conclusions

The majority of patients with bone metastasis were not working at the start of or after radiation therapy, but the number of patients who were working was not negligible. Radiation oncologists should be aware of the working status of patients and provide appropriate support for each patient. The benefit of radiation therapy to support patients continuing their work and returning to work should be investigated further in prospective studies.

The impact of the COVID-19 pandemic on radiotherapy in Japan: nationwide surveys from May 2020 through June 2021

A longitudinal online questionnaire survey on the impact of coronavirus disease 2019 (COVID-19) on the operation of radiotherapy departments in Japan was conducted. Approximately 26.1-70.9% of the radiotherapy departments participated, and their responses were collected in May, July and November 2020, and February and June 2021. The survey results revealed that while the number of patients receiving radiotherapy decreased in 41.2% and 30.7% of institutions in May 2020 and June 2021, respectively, it increased in 4% and 16.8% of institutions in May 2020 and June 2021, respectively. There were a few institutions limiting or postponing patient treatments in June 2021. The hypofractionated regimen was used more during the pandemic than during the pre-pandemic period, particularly for the treatment of breast and prostate cancers as well as for palliation. Infection control measures for patients and staff were followed. Approximately 20% of the respondent institutions had cases of patients with COVID-19 infection receiving radiotherapy. Most institutions encountered challenges in the continuous provision of radiotherapy for patients with COVID-19. In conclusion, COVID-19 had a multifaceted impact on the operations of radiotherapy departments in Japan. Further follow-up and analysis are warranted to understand the long-term impact of COVID-19 on radiotherapy.

Practical guidelines of online MR-guided adaptive radiotherapy

The first magnetic resonance (MR)-guided radiotherapy system in Japan was installed in May 2017. Implementation of online MR-guided adaptive radiotherapy (MRgART) began in February 2018. Online MRgART offers greater treatment accuracy owing to the high soft-tissue contrast in MR-images (MRI), compared to that in X-ray imaging. The Japanese Society for Magnetic Resonance in Medicine (JSMRM), Japan Society of Medical Physics (JSMP), Japan Radiological Society (JRS), Japanese Society of Radiological Technology (JSRT), and Japanese Society for Radiation Oncology (JASTRO) jointly established the comprehensive practical guidelines for online MRgART. These guidelines propose the essential requirements for clinical implementation of online MRgART with respect to equipment, personnel, institutional environment, practice guidance, and quality assurance/quality control (QA/QC). The minimum requirements for related equipment and QA/QC tools, recommendations for safe operation of MRI system, and the implementation system are described. The accuracy of monitor chamber and detector in dose measurements should be confirmed because of the presence of magnetic field. The ionization chamber should be MR-compatible. Non-MR-compatible devices should be used in an area that is not affected by the static magnetic field (outside the five Gauss line), and their operation should be checked to ensure that they do not affect the MR image quality. Dose verification should be performed using an independent dose verification system that has been confirmed to be reliable through commissioning. This guideline proposes the checklists to ensure the safety of online MRgART. Successful clinical implementation of online MRgART requires close collaboration between physician, radiological technologist, nurse, and medical physicist.

Applying Artificial Neural Networks to Develop a Decision Support Tool for Tis-4N0M0 Non-Small-Cell Lung Cancer Treated With Stereotactic Body Radiotherapy

PURPOSE

Clear evidence indicating whether surgery or stereotactic body radiation therapy (SBRT) is best for non-small-cell lung cancer (NSCLC) is lacking. SBRT has many advantages. We used artificial neural networks (NNs) to predict treatment outcomes for patients with NSCLC receiving SBRT, aiming to aid in decision making.

PATIENTS AND METHODS

Among consecutive patients receiving SBRT between 2005 and 2019 in our institution, we retrospectively identified those with Tis-T4N0M0 NSCLC. We constructed two NNs for prediction of overall survival (OS) and cancer progression in the first 5 years after SBRT, which were tested using an internal and an external test data set. We performed risk group stratification, wherein 5-year OS and cancer progression were stratified into three groups.

RESULTS

In total, 692 patients in our institution and 100 patients randomly chosen in the external institution were enrolled. The NNs resulted in concordance indexes for OS of 0.76 (95% CI, 0.73 to 0.79), 0.68 (95% CI, 0.60 to 0.75), and 0.69 (95% CI, 0.61 to 0.76) and area under the curve for cancer progression of 0.80 (95% CI, 0.75 to 0.84), 0.72 (95% CI, 0.60 to 0.83), and 0.70 (95% CI, 0.57 to 0.81) in the training, internal test, and external test data sets, respectively. The survival and cumulative incidence curves were significantly stratified. NNs selected low-risk cancer progression groups of 5.6%, 6.9%, and 7.0% in the training, internal test, and external test data sets, respectively, suggesting that 48% of patients with peripheral Tis-4N0M0 NSCLC can be at low-risk for cancer progression.

CONCLUSION

Predictions of SBRT outcomes using NNs were useful for Tis-4N0M0 NSCLC. Our results are anticipated to open new avenues for NN predictions and provide decision-making guidance for patients and physicians.

Mean heart dose-based normal tissue complication probability model for pericardial effusion: a study in oesophageal cancer patients

We investigated the normal tissue complication probability (NTCP) of the incidence of pericardial effusion (PCE) based on the mean heart dose (MHD) in patients with oesophageal cancer treated with definitive chemoradiotherapy. The incidences of PCE in any grade (A-PCE) and symptomatic PCE (S-PCE) were evaluated separately. To identify predictors for PCE, several clinical and dose-volume parameters were analysed using a receiver operating characteristic (ROC) curve and multivariate regression analysis. To validate its clinical applicability, the generated NTCP model was compared to the Lyman–Kutcher–Burman (LKB) model. Among 229 eligible patients, A-PCE and S-PCE were observed in 100 (43.7%) and 18 (7.9%) patients, respectively. MHD showed a preferable area under the curve (AUC) value for S-PCE (AUC = 0.821) and A-PCE (AUC = 0.734). MHD was the only significant predictor for A-PCE; MHD and hypertension were selected as significant factors for S-PCE. The estimated NTCP, using the MHD-based model, showed excellent correspondence to the LKB model in A-PCE and S-PCE. The NTCP curve of A-PCE was gentler than that of S-PCE and had no threshold. The MHD-based NTCP model was simple but comparable to the LKB model for both A-PCE and S-PCE. Therefore, the estimated NTCP may provide clinically useful parameters for predicting PCE.

Effects of sample size and data augmentation on U-Net-based automatic segmentation of various organs

Deep learning has demonstrated high efficacy for automatic segmentation in contour delineation, which is crucial in radiation therapy planning. However, the collection, labeling, and management of medical imaging data can be challenging. This study aims to elucidate the effects of sample size and data augmentation on the automatic segmentation of computed tomography images using U-Net, a deep learning method. For the chest and pelvic regions, 232 and 556 cases are evaluated, respectively. We investigate multiple conditions by changing the sum of the training and validation datasets across a broad range of values: 10-200 and 10-500 cases for the chest and pelvic regions, respectively. A U-Net is constructed, and horizontal-flip data augmentation, which produces left and right inverse images resulting in twice the number of images, is compared with no augmentation for each training session. All lung cases and more than 100 prostate, bladder, and rectum cases indicate that adding horizontal-flip data augmentation is almost as effective as doubling the number of cases. The slope of the Dice similarity coefficient (DSC) in all organs decreases rapidly until approximately 100 cases, stabilizes after 200 cases, and shows minimal changes as the number of cases is increased further. The DSCs stabilize at a smaller sample size with the incorporation of data augmentation in all organs except the heart. This finding is applicable to the automation of radiation therapy for rare cancers, where large datasets may be difficult to obtain.

Radiation dose rate variations in different measurement scenarios after prostate 125I brachytherapy

PURPOSE

This study aimed to directly compare different measurement scenarios using a supplemental radiation exposure measurement data set.

MATERIALS AND METHODS

Two sets of measurement scenarios comparing different body postures, such as standing and chair sitting positions, and different measurement directions, such as anterior and posterior directions, were assessed for radiation dose rate variations in this study at the Tokyo Medical Center, Japan. The estimated precaution time for holding children in the spoon position while sitting was also calculated.

RESULTS

Different radiation dose rate measurement scenarios showed different variation tendencies. Radiation dose rate measurement showed higher mean values of measured radiation dose tendency in the standing position than in the sitting positions. The measurement from the anterior direction showed a slightly lower tendency than that from the posterior direction. Assuming a dose limit of 1 mSv, the precaution time calculated for children being held in the spoon position for a certain duration every day was 51.5 (range, 12.5-152.2) minutes.

CONCLUSIONS

Our study presented a supplemental radiation exposure measurement data set and directly compared different measurement scenarios. Several trends in radiation exposure variations were found in the measurement scenarios at different body postures and different measurement directions. Our study data set could be a useful source of concrete information regarding radiation safety and contribute to the review and revision of public guidance in the future.

Sensitivity improvement of infrared imaging video bolometer for divertor plasma measurement

The sensitivity of an infrared imaging video bolometer (IRVB) was improved for the measurement of relatively low energy plasma radiation from the viewpoint of the metal foil absorber material. The photon energy of the radiation was considered up to 1 keV for the divertor plasma measurement. The thickness of the foil absorber was evaluated not only for conventional heavy elements, e.g., platinum, but also for light elements by the relation between the photon energy and attenuation length and by mechanical strength. A heat-transfer calculation using ANSYS suggested that light elements with practical foil thickness provide a higher temperature rise of the foil absorber compared with heavier elements with practical foil thickness. The maximum of the temperature rise was evaluated using He-Ne laser irradiation onto absorber samples. The material dependence of the temperature rise has a similar tendency between calculations and experiments. Experimentally, the sensitivity of the IRVB improved from 280 to 110 µW/cm² using titanium with 1 µm thickness compared with conventional platinum with 2.5 µm thickness. Consequently, the signal-to-noise ratio of the IRVB could be improved from 2.8 to 9.1.

Proton beam therapy for children and adolescents and young adults (AYAs): JASTRO and JSPHO Guidelines

Children and adolescents and young adults (AYAs) with cancer are often treated with a multidisciplinary approach. This includes use of radiotherapy, which is important for local control, but may also cause adverse events in the long term, including second cancer. The risks for limited growth and development, endocrine dysfunction, reduced fertility and second cancer in children and AYAs are reduced by proton beam therapy (PBT), which has a dose distribution that decreases irradiation of normal organs while still targeting the tumor. To define the outcomes and characteristics of PBT in cancer treatment in pediatric and AYA patients, this document was developed by the Japanese Society for Radiation Oncology (JASTRO) and the Japanese Society of Pediatric Hematology/Oncology (JSPHO).

Dosimetric study of whole-brain irradiation with high-energy photon beams for dose reduction to the scalp

OBJECTIVE

To evaluate the efficiency of high-energy photons for mitigating alopecia due to whole-brain irradiation (WBRT).

METHODS

Planning CT data from 10 patients who received WBRT were collected. We prepared 4 WBRT plans that used 6 or 15 MV photon beams, with or without use of a field-in-field (FiF) technique, and compared outcomes using a treatment planning system. The primary outcome was dose parameters to the scalp, including the mean dose, maximum dose, and dose received to 50% scalp(D50%). Secondary outcomes were minimum dose to the brain surface.

RESULTS

Using FiF, the mean doses were 24.4-26.0 and 22.4-24.1 Gy, and the maximum doses were 30.5-32.1 and 28.5-30.8 Gy for 6 and 15 MV photon beams, respectively. Without FiF, the mean doses were 24.6-26.9 and 22.6-24.5 Gy, and the maximum doses were 30.8-34.6 and 28.6-32.4 Gy for 6 and 15 MV photon beams. The 15 MV plan resulted in a lower scalp dose for each dose parameter (p < 0.001). Using FiF, the minimum doses to the brain surface for the 6 and 15 MV plans were 28.9 ± 0.440 and 29.0 ± 0.557 Gy, respectively (p = 0.70). Without FiF, the minimum doses to the brain surface for the 6 and 15 MV plans were 28.9 ± 0.456 and 29.0 ± 0.529, respectively (p = 0.66).

CONCLUSION

Compared with the 6 MV plan, the 15 MV plan achieved a lower scalp dose without impairing the brain surface dose.

ADVANCES IN KNOWLEDGE

High-energy photon WBRT may mitigate alopecia of patients who receiving WBRT.

Comparison of prostate verification with implanted gold markers in tissue surrounding the prostate and pelvic bony anatomy for external beam radiation therapy following low-dose-rate brachytherapy: a prospective clinical trial

We aimed to investigate whether gold marker implantation in the tissue surrounding the prostate could accurately monitor setup errors during external beam radiation therapy (EBRT) following low-dose-rate (LDR) brachytherapy. Thirty-eight patients had confirmed intermediate- or high-risk prostate cancer and received EBRT following LDR brachytherapy. In >175 computed tomography imaging sessions, the average values of the weekly setup error during EBRT to the prostate centroid at the time of gold marker matching in the surrounding tissue of the prostate and pelvic bone matching were measured and then compared using the Wilcoxon signed-rank test. Gold marker matching in the surrounding tissue of the prostate estimated setup errors better than those estimated by bone matching (3D displacement = 2.7 ± 2.0 vs 3.8 ± 2.6 mm, P < 0.01). Overall, the standard deviation of systematic (Σ) and random (σ) setup error was lower with gold marker matching than with bone matching (3D displacement = 1.8 and 1.1 mm vs 2.1 and 1.6 mm, respectively). With gold marker matching, the setup error of the position of the prostate centroid was smaller, and the optimal setup margin was lower than that with bone matching (2Σ + 0.7σ and 2.5Σ + 0.7σ of 3D displacement = 4.3 and 5.2 mm vs 5.3 and 6.4 mm, respectively). This high-precision radiotherapy approach placing gold markers in the surrounding tissue of the prostate can allow more accurate setup during EBRT following LDR brachytherapy.

Relationship between radiation doses and erectile function deterioration in patients with localized prostate cancer treated with permanent prostate brachytherapy

OBJECTIVES

To investigate the relationship between radiation doses in prostate brachytherapy and deterioration of erectile function in patients with localized prostate cancer.

METHODS

A longitudinal survey study was carried out among 261 prostate cancer patients who received prostate brachytherapy. A total of 48 patients were potent at baseline and they did not receive any supplemental therapy preoperatively. Dosimetry parameters of the whole prostate gland, prostate apex, urethra and rectum were collected using the VariSeed 8.0 treatment planning system (Varian Medical Systems, Palo Alto, CA, USA). We carried out a logistic regression analysis to clarify the relationship between radiation doses and erectile function deterioration, which was assessed using the International Index of Erectile Function-15 questionnaire.

RESULTS

The median patient age was 66 years (range 53-70 years) with a median follow-up time of 44 months (36-71 months). The mean total International Index of Erectile Function-15 score decreased from 49.9 at baseline to 34.7 after 12 months (P < 0.001), but gradually plateaued within 36 months. Erectile function deterioration was noted in 32 (66.7%) patients 36 months after prostate brachytherapy. In an analysis of risk factors for erectile function deterioration after prostate brachytherapy, age ≥70 years (P = 0.029), prostate V100 ≥95% (P = 0.024), apex V100 ≥95% (P = 0.024), apex V150 ≥70% (P = 0.009) and apex D90 ≥150 Gy (P = 0.011) correlated with erectile function deterioration. A multivariate analysis identified an age of ≥70 years (odds ratio 7.91, P = 0.024) and apex V150 ≥70% (odds ratio 7.75, P = 0.007) as independent risk factors for erectile function deterioration after prostate brachytherapy.

CONCLUSIONS

An excessive radiation dose, particularly to the prostate apex area, and an advanced age might have a negative impact on the preservation of potency after prostate brachytherapy.

Efficacy evaluation of 2D, 3D U-Net semantic segmentation and atlas-based segmentation of normal lungs excluding the trachea and main bronchi

This study aimed to examine the efficacy of semantic segmentation implemented by deep learning and to confirm whether this method is more effective than a commercially dominant auto-segmentation tool with regards to delineating normal lung excluding the trachea and main bronchi. A total of 232 non-small-cell lung cancer cases were examined. The computed tomography (CT) images of these cases were converted from Digital Imaging and Communications in Medicine (DICOM) Radiation Therapy (RT) formats to arrays of 32 × 128 × 128 voxels and input into both 2D and 3D U-Net, which are deep learning networks for semantic segmentation. The number of training, validation and test sets were 160, 40 and 32, respectively. Dice similarity coefficients (DSCs) of the test set were evaluated employing Smart SegmentationⓇ Knowledge Based Contouring (Smart segmentation is an atlas-based segmentation tool), as well as the 2D and 3D U-Net. The mean DSCs of the test set were 0.964 [95% confidence interval (CI), 0.960-0.968], 0.990 (95% CI, 0.989-0.992) and 0.990 (95% CI, 0.989-0.991) with Smart segmentation, 2D and 3D U-Net, respectively. Compared with Smart segmentation, both U-Nets presented significantly higher DSCs by the Wilcoxon signed-rank test (P < 0.01). There was no difference in mean DSC between the 2D and 3D U-Net systems. The newly-devised 2D and 3D U-Net approaches were found to be more effective than a commercial auto-segmentation tool. Even the relatively shallow 2D U-Net which does not require high-performance computational resources was effective enough for the lung segmentation. Semantic segmentation using deep learning was useful in radiation treatment planning for lung cancers.

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.

Radiotherapy for localized sebaceous carcinoma of the eyelid: a retrospective analysis of 83 patients

The current study retrospectively analyzed the results of radiotherapy for clinically localized sebaceous carcinoma of the eyelid.We reviewed records of 83 patients with histologically confirmed sebaceous carcinoma who were treated radiotherapeutically between 1983 and 2015. Sixty-five patients (78%) were initially treated with radiotherapy of curative intent, while the remaining 18 patients underwent postoperative radiotherapy due to tumor recurrence or positive surgical margins. Thirty-seven patients belonged to T1-2, while 46 belonged to T3-4. All 83 patients were treated with radiotherapy with a median radiation dose of 60 Gy. The median follow-up period was 92.1 months (range, 2.8-310.3 months). At the time of analysis, 13 patients (15.1%) died, and 36 patients (43.3%) had local recurrence. The 7-year overall survival, freedom from neck lymph node recurrence, and local control (LC) rates for all patients were 83.5%, 75.5%, and 52.3%, respectively. Patients with a tumor size ≤10 mm had a higher 7-year LC rate than those with a tumor size >10 mm (58.8% vs 46.6%, P = 0.054). Neck lymph node recurrence was observed in 17 patients (20%) and significantly related to the tumor size. Late toxicity of an eyelid dysfunction of grade 3 was observed in 1 patient with T3 tumor. Radiotherapy for sebaceous carcinoma of the eyelid is a reasonable alternative to surgical resection for tumors <10 mm in size with few severe complications, while larger tumors should be treated with surgery if feasible.

Pleural contact decreases survival in clinical T1N0M0 lung cancer patients undergoing SBRT

BACKGROUND

Clinical staging, as used for patients treated with stereotactic body radiotherapy (SBRT) for early-stage lung cancer, inadequately accounts for pleural invasion, which is a pathologic criteria. Considering the current situation, we analyzed effects of relationships between tumors and the pleura on treatment outcomes of SBRT for early-stage lung cancer.

MATERIALS AND METHODS

Among consecutive patients treated with SBRT between 2006 and 2017, we retrospectively identified non-small cell lung cancer patients with primary tumor diameters ≤4 cm and N0M0. The relationships between tumors and the pleura were investigated. The effects of these findings on treatment outcomes were analyzed.

RESULTS

We identified 386 patients which met the inclusion criteria. Among these patients, 323 patients were with tumors of 0.1-3.0 cm (T1-size), and 63 patients were with tumors of 3.1-4.0 cm (T2a-size). Among patients with T1-size tumors, 120, 134, and 23 had findings of pleural contact, pleural indentation, and pleural thickening, respectively. When we divided T1-size patients into 2 groups based on pleural contact (contact- or contact+), the 3-year cause-specific mortality and overall survival in patients with T1-size & contact+ were significantly worse than those in patients with T1-size & contact- (17.6% (95% confidence interval (CI), 10.7-25.9%) vs. 6.6% (95% CI, 3.5-11.1%), p < 0.01), and 58.2% (95% CI, 47.6-67.5%) vs. 77.6% (95% CI, 70.5-83.2%), p < 0.01). Local recurrence, regional recurrence, pleural cavity recurrence, and distant metastasis were associated with worse cause-specific mortality and overall survival. On multivariate analysis, pleural contact was associated with cause-specific mortality (hazard ratio (HR), 1.96; 95% CI, 1.09-3.52; p = 0.03) and overall survival (HR, 1.59; 95% CI, 1.08-2.34; p = 0.02).

CONCLUSION

Pleural contact in clinical T1N0M0 lung cancer patients was associated with significantly worse survivals.

A Highly Advanced Gastric Cancer Maintaining a Clinical Complete Response after Chemoradiotherapy Comprising S-1 and Cisplatin

We report a patient with highly advanced gastric carcinoma who was treated successfully with chemoradiotherapy (CRT) comprising S-1 and cisplatin. The patient was a 71-year-old male who was diagnosed with advanced gastric carcinoma by esophagogastroduodenoscopy (EGD) by medical examination. EGD demonstrated type 3 advanced gastric carcinoma in the posterior wall of the upper gastric body. An abdominal computed tomography (CT) scan showed that the gastric wall was thickened due to gastric primary tumor, and large lymph nodes (LNs) including the lesser curvature LN, anterosuperior LN along the common hepatic artery and some para-aortic LNs were detected. The patient was diagnosed with stage IV advanced gastric carcinoma according to the Japanese classification of gastric carcinoma (cT4a, cN3, cM1 [para-aortic LN], cStage IV). Preoperative CRT was carried out in an attempt to downstage the disease. Remarkable reduction of the primary tumor and metastatic LNs was observed after initial CRT, and radiological examination determined that a partial response had been achieved. Adverse effects included grade 2 anorexia and grade 3 ALP elevation (919 U/ml). No grade 4 or more severe adverse event was observed. After CRT, although we recommended curative surgery, the patient refused surgical treatment and opted for conservative treatment. Thus, we continued S-1 oral administration for 1 year. Five months after beginning CRT, upper endoscopy showed that the tumor had maintained regression and scar formation, in which no cancer cells were detected by endoscopic biopsy. The patient is doing well and has maintained a clinical complete response for more than 42 months without curative surgery. CRT could be considered as an option for treatment of patients with locally advanced gastric carcinoma diagnosed as unresectable, or for those who refuse surgical treatment.

Low-Dose Induction Radiotherapy for Stomach Conservation in Patients with Massive Gastric Lymphoma

Low-dose induction radiotherapy was performed in 4 patients with massive gastric lymphoma in order to treat the disease without gastrectomy. Following the radiotherapy, gastric lesions had shrunk considerably without any complications. Standard chemotherapy and/or radiotherapy could then be performed safely, and stomach conservation could be achieved in all 4 patients.

Long-term results of concurrent chemoradiotherapy with daily-low-dose continuous infusion of 5-fluorouracil and cisplatin (LDFP) for Stage I-II esophageal carcinoma

We investigated long-term treatment outcomes and the feasibility of chemoradiotherapy consisting of daily-low-dose 5-fluorouracil and cisplatin (LDFP) chemotherapy plus radiotherapy for Stage I-II squamous cell esophageal cancer. Treatment records from the 2000 through 2008 period were reviewed retrospectively. Fractionated radiotherapy was performed with a total dose of 60 Gy delivered in 2 Gy per fraction. LDFP chemotherapy, as continuous infusion of 200 mg/m2 5-fluorouracil combined with one hour infusion of 4 mg/m2 cisplatin, was administered on the same days as radiotherapy. Survival was calculated by the Kaplan-Meier method. Survival, responses, failure patterns, and toxicities were evaluated. Seventy-six (47 stage I and 29 stage II) patients were analyzed with a median follow-up of 93.6 months. The 8-year overall survival (OS), progression-free survival (PFS) and cause-specific survival (CSS) rates were 63.4%, 49.8%, and 76.7%, respectively. The 8-year OS, PFS, and CSS for stage I and stage II patients were 71.0%/56.1%/82.9% and 45.2%/40.2%/66.6%, respectively. Sixty-eight patients (89.5%) completed the treatment regimen. A complete response (CR) was achieved in 68 patients (89.5%). Twenty-five patients (36.8%) experienced recurrence after CR. The failure patterns were (overlap included): local failure (n = 12), nodal metastasis (n = 12), distant metastasis (n = 3), details unknown (n = 2). Salvage therapy was performed for local failure; endoscopic therapy (n = 7) or surgery (n = 2). Six patients remain alive without relapse after salvage endoscopic therapy. Major Grade 3 or higher acute adverse events were leukopenia (22%), anorexia (17%), and esophagitis (11%). Major late toxicities (Grade 3 or 4) involved pericardial effusion (12%), pleural effusion (4%), and esophageal stenosis (3%). Chemoradiotherapy with LDFP provided favorable long-term survival with acceptable toxicity for Stage I-II squamous cell esophageal cancer. The tumor response was excellent, but close endoscopic follow-up is essential for detecting and treating local recurrence.

Prostate-specific antigen nadir within 12 months as an early surrogate marker of biochemical failure and distant metastasis after low-dose-rate brachytherapy or external beam radiotherapy for localized prostate cancer

Prostate-specific antigen nadir (nPSA) after radiotherapy for localized prostate cancer has been investigated as a predictor. However, nPSA usually requires several years, limiting its clinical utility. We investigated the significance of nPSA within 12 months (nPSA12) after low-dose-rate prostate brachytherapy (LDR-PB) or external beam radiotherapy (EBRT) on treatment outcomes. Between 2006 and 2014, 663 patients with prostate cancer were treated with LDR-PB or EBRT at two institutions. Four hundred and seventy-four men received LDR-PB and 189 men received EBRT, without androgen deprivation therapy. The Kaplan-Meier method was used for biochemical failure (BF)-free survival (BFFS) and distant metastasis (DM)-free survival (DMFS) analyses, and multivariable Cox regression analysis was performed. The median follow-up was 61.3 months. The median nPSA12 in the LDR-PB and EBRT cohorts was 0.7 and 1.0 ng/mL, respectively. The 7-year BFFS and DMFS rates in LDR-PB patients with nPSA12 ≤ 0.7 ng/mL were 99.1% and 99.5%, respectively; when nPSA12 was >0.7 ng/mL, they were 90.2% and 94.8%, respectively. In EBRT patients with nPSA12 ≤ 1.0 ng/mL, BFFS and DMFS rates were 85.4% and 98.5%, respectively; when nPSA12 was >1.0 ng/mL, they were 67.1% and 87.2%, respectively. nPSA12 was an independent predictor of BF and DM in both cohorts (LDR-PB, P = 0.004 and 0.020, respectively; EBRT, P = 0.005 and 0.041, respectively). The nPSA12 after LDR-PB or EBRT is significantly associated with treatment outcomes of prostate cancer. Higher nPSA12 may identify patients at high risk of relapse who might benefit from salvage treatment.

Long-term Clinical Results of Concurrent Chemoradiotherapy for Patients with Cervical Esophageal Squamous Cell Carcinoma

BACKGROUND/AIM

We assessed the efficacy and toxicity of concurrent chemoradiotherapy (CCRT) in patients with squamous cell carcinoma of the cervical esophagus.

PATIENTS AND METHODS

We retrospectively analyzed 37 patients treated with definitive CCRT. The patients received radiotherapy at a fraction dose of 2 Gy (total; 60 or 70 Gy) and concurrent chemotherapy. Adjuvant chemotherapy consisted of 1 to 2 cycles of 5-fluorouracil plus cisplatin or nedaplatin.

RESULTS

The median follow-up was 119.0 months, the 10-year overall survival, progression-free survival and laryngectomy-free survival rates were 35.6, 19.9 and 30.2% respectively. In the univariate analysis, T stage (T4 vs. T1-3) was the only prognostic factor for PFS. The most common acute toxicity was leukocytopenia (Grade 3; 27%). As for late toxicities, 4 patients (11%) developed Grade 2 or 3 esophageal strictures.

CONCLUSION

The results of this study demonstrated that CCRT yielded satisfactory clinical outcomes with acceptable toxicities.

Quantitative analysis of genitourinary toxicity after iodine-125 brachytherapy for localized prostate cancer: Followup of the International Prostate Symptom Score and Overactive Bladder Symptom Score

PURPOSE

To analyze genitourinary toxicity by followup of the International Prostate Symptom Score (IPSS) and Overactive Bladder Symptom Score (OABSS) after prostate brachytherapy.

METHODS AND MATERIALS

Six hundred eighty patients were treated with iodine-125 brachytherapy for localized prostate cancer. IPSS, OABSS, and two categories of IPSS questions (storage symptom score [IPSS-S] and voiding symptom score [IPSS-V]) were evaluated.

RESULTS

The median followup was 54 months (range, 24-108). All scales showed rapid increases followed by gradual decreases. The median times to IPSS peak and resolution were 1 and 6 months, respectively. The resolution rates of IPSS, IPSS-S, IPSS-V, and OABSS at the last followup were 84.2%, 86.3%, 89.5%, and 83.0%, respectively. The difference between IPSS baseline and peak was greater for larger preimplant prostate volumes (≥25 mL, p = 0.004). The time to resolution was longer for higher biologic effective dose (BED) (≥210 Gy, p = 0.019 [IPSS]), in those with larger prostate volumes (≥25 mL, p = 0.025 [OABSS]), in younger patients (younger than 70 years, p = 0.043 [IPSS-S]), and in those with androgen deprivation therapy (ADT) use (p = 0.049 [IPSS-V]). Urge incontinence, included in the OABSS, was observed more commonly in older patients (75 years and older, p = 0.018), with ADT use (p < 0.001), and for higher BED (≥210 Gy, p = 0.006).

CONCLUSIONS

The IPSS and OABSS showed similar patterns of change. Urinary symptoms improved more rapidly in those with high baseline IPSS levels. The OABSS was useful for following urinary symptoms after prostate brachytherapy. Age, ADT use, preimplant prostate volume, and BED were significantly associated with urinary outcomes.

Stereotactic body radiotherapy for operable early-stage non-small cell lung cancer

PURPOSE

To analyze outcomes of stereotactic body radiotherapy (SBRT) for operable patients with early-stage non-small cell lung cancer (NSCLC) and to evaluate factors associated with outcomes.

METHODS

We retrospectively analyzed operable patients with NSCLC, staged as cT1-2N0M0, treated with SBRT between 2006 and 2015. Both biopsy-proven and clinically diagnosed NSCLC were included. Local control and survival rates were calculated and compared between subsets of patients. We investigated factors associated with outcomes.

RESULTS

We identified 88 operable patients among 661 patients with cT1-2N0M0 NSCLC. The median age was 79 years (range: 55-88). The median follow-up time after SBRT was 40 months (range: 4-121). Fifty-nine patients had been pathologically diagnosed and the other 29 had been clinically diagnosed as having NSCLC. Local control, cause-specific survival (CSS) and overall survival (OS) at 3 years were 91%, 97% and 90% for T1, and 100%, 82% and 74% for T2, respectively. The CSS and OS at 3 years were 100% and 100% for GGO and 83% and 59% for solid tumors, respectively (p=0.005). On univariate analysis, age and T stage were significantly associated with CSS, and age, the Charlson Comorbidity Index (CCI), and opacity were significantly associated with OS. On multivariate analysis, age and CCI were significantly associated with OS. As for toxicities, Grades 0, 1, 2 and 3 radiation pneumonitis occurred in 37.5%, 47.7%, 13.6% and 1.1% of patients, respectively. No Grade 4 or 5 radiation pneumonitis occurred, and no other toxicities of Grade 2 or above were observed.

CONCLUSION

Outcomes of SBRT for operable early stage NSCLC were as good as previous SBRT and surgery studies. Further investigation for selecting good SBRT candidates is warranted in high-risk operable patients.

Influence of backscatter radiation on cranial reconstruction implants

OBJECTIVE

We aimed to evaluate backscatter dose variations in different cranial bone implant materials in an experimental model designed to simulate post-operative radiotherapy.

METHODS

We assessed the radiation backscatter doses associated with sheet- and mesh-type titanium plates and hydroxyapatite (HAP) samples (porosity: 35%, 50% and 85%). The samples were irradiated with 6- and 10-MV photon beams from a linear accelerator. Measurements were obtained using an ionization chamber and radiochromic films cut from the same batch.

RESULTS

At 6 MV, the titanium sheet showed the highest peak for backscattered radiation, followed by (in decreasing order) HAP30%, HAP50%, titanium mesh and HAP85%. At 10 MV, HAP30% showed the highest peak, followed by HAP50%, titanium sheet, titanium mesh and HAP85%. The peaks were at different depths in the titanium and HAP samples. The thickness of the human scalp is approximately 7 mm; therefore, measurements were obtained 0-7 mm above the implants to assess the likely dose on the scalp. A comparison of the maximum dose on the scalp showed the titanium sheet had the highest dose at both 6 and 10 MV.

CONCLUSION

The backscatter dose differed with the density of the material and the backscatter depth was different for each material. Advances in knowledge: Ulcer formation due to radiotherapy after brain tumour depends on not only radiation but also the implant material. Therefore, the density and type of implant material should be considered when planning radiotherapy and selecting bone reconstruction materials.

Stereotactic body radiotherapy for T3 and T4N0M0 non-small cell lung cancer

To evaluate the outcomes and feasibility of stereotactic body radiotherapy (SBRT) for cT3 and cT4N0M0 non-small cell lung cancer (NSCLC), 25 patients with localized primary NSCLC diagnosed as cT3 or cT4N0M0, given SBRT between May 2005 and July 2013, were analyzed. All patients had inoperable tumors. The major reasons for tumors being unresectable were insufficient respiratory function for curative resection, advanced age (>80 years old) or technically inoperable due to invasion into critical organs. The median patient age was 79 years (range; 60-86). The median follow-up duration was 25 months (range: 5-100 months). The 2-year overall survival rates for T3 and T4 were 57% and 69%, respectively. The 2-year local control rates for T3 and T4 were 91% and 68%, respectively. As for toxicities, Grade 0-1, Grade 2 and Grade 3 radiation pneumonitis occurred in 23, 1 and 1 patient, respectively. No other acute or symptomatic late toxicities were reported. Thirteen patients who had no local, mediastinal or intrapulmonary progression at one year after SBRT underwent pulmonary function testing. The median variation in pre-SBRT and post-SBRT forced expiratory volume in 1 s (FEV1) values was -0.1 (-0.8-0.8). This variation was not statistically significant (P = 0.56). Forced vital capacity (FVC), vital capacity (VC), %VC and %FEV1 also showed no significant differences. SBRT for cT3 and cT4N0M0 NSCLC was both effective and feasible. Considering the favorable survival and low morbidity rate, SBRT is a potential treatment option for cT3 and cT4N0M0 NSCLC.

Prospective study of direct radiation exposure measurements for family members living with patients with prostate (125)I seed implantation: Evidence of radiation safety

PURPOSE

To broaden the current understanding of radiation exposure and risk and to provide concrete evidence of radiation safety related to (125)I seed implantation.

METHODS AND MATERIALS

Direct radiation exposure measurements were obtained from dosimeters provided to 25 patients who underwent (125)I seed implantation, along with their family members. The estimated lifetime exposure dose and the precaution time for holding children near the patient's chest were calculated in two study periods.

RESULTS

During the first and second study period, the mean estimated lifetime exposure doses were, respectively, 7.61 (range: 0.45, 20.21) mSv and 6.84 (range: 0.41, 19.20) mSv for patients, and 0.19 (range: 0.02, 0.54) mSv and 0.25 (range: 0.04, 1.00) mSv for family members. The mean ratios of first and second period measurements were 1.05 (range: 0.44, 3.18) for patients and 1.82 (range: 0.21, 7.04) for family members. The corresponding absolute differences between first and second period measurements were -0.77 (range: -11.40, 7.63) mSv and 0.06 (range: -0.26, 0.79) mSv, respectively. Assuming a dose limit of 1 mSv, the precaution times for holding a child every day of the first and second periods were 250.9 (range: 71.3, 849.4) min and 275.2 (range: 75.0, 883.4) min, respectively. Assuming a dose limit of 0.5 mSv, the corresponding precaution times were 179.0 (range: 35.6, 811.5) min and 178.9 (range: 37.5, 1131.8) min, respectively.

CONCLUSIONS

Our study demonstrated low radiation exposures to family members of patients undergoing (125)I prostate implantation. It was clear that (125)I seed implantation did not pose a threat to the safety of family members.

Predictive factors for urinary toxicity after iodine-125 prostate brachytherapy with or without supplemental external beam radiotherapy

PURPOSE

We examined the factors associated with urinary toxicities because of brachytherapy with iodine-125 with or without supplemental external beam radiotherapy (EBRT) for prostate cancer.

METHODS AND MATERIALS

We investigated 1313 patients with localized prostate cancer treated with iodine-125 brachytherapy with or without supplemental EBRT between 2003 and 2009. The International Prostate Symptom Score (IPSS) and Common Terminology Criteria for Adverse Events data were prospectively determined. Patients, treatment, and implant factors were investigated for their association with urinary toxicity or symptoms.

RESULTS

IPSS resolution was not associated with biologically effective dose (BED). Baseline IPSS, total needles, and the minimal dose received by 30% of the urethra had the greatest effect according to multivariate analysis (MVA). Urinary symptom flare was associated with baseline IPSS, age, BED, and EBRT on MVA. Urinary symptom flare and urinary Grade 2 or higher (G2+) toxicity occurred in 51%, 58%, and 67% (p = 0.025) and 16%, 22%, and 20% (p = 0.497) of the <180, 180-220, and >220 Gy BED groups, respectively. Urinary G2+ toxicity was associated with baseline IPSS, neoadjuvant androgen deprivation therapy (NADT), and seed density on MVA. When we divided patients into four groups according to prostate volume (<30 cc or ≥30 cc) and NADT use, urinary G2+ toxicity was most commonly observed in those patients with larger prostates who received NADT, and least in the patients with smaller prostates and no NADT.

CONCLUSIONS

NADT was associated with urinary G2+ toxicity. Higher dose and supplemental EBRT did not appear to increase moderate to severe urinary toxicities or time to IPSS resolution; however, it influenced urinary symptom flare.

Erectile function status is highly associated with prostate-specific antigen bounce in localized prostate cancer patients treated with permanent prostate brachytherapy

OBJECTIVES

To examine the relationship between erectile function status and prostate-specific antigen bounce after prostate brachytherapy for localized prostate cancer.

METHODS

We identified 154 patients who were followed up for at least 24 months after brachytherapy. Erectile function status was assessed prospectively before brachytherapy (baseline), and 3, 6, 12, 18, 24 and 36 months postoperatively using the International Index of Erectile Function-15 questionnaire. Prostate-specific antigen bounce was defined as an increase of at least 0.4 ng/mL from a previous prostate-specific antigen level with a subsequent decline equal to, or less than, the initial nadir without treatment. A logistic regression analysis was used to identify a significant set of independent predictors of prostate-specific antigen bounce after brachytherapy.

RESULTS

Prostate-specific antigen bounce was observed in 38 (24.7%) men. The prostate-specific antigen bounce group had a higher erectile function domain score, higher orgasmic function domain score, and higher total International Index of Erectile Function-15 score before (at baseline) and after brachytherapy (3, 6, 12, 18, 24 and 36 months after brachytherapy) than their counterparts (P < 0.05). Of the 77 patients who completed the International Index of Erectile Function-15 questionnaire 18 months after brachytherapy (the median time of prostate-specific antigen bounce), sexual desire and intercourse satisfaction domain scores, and total International Index of Erectile Function scores 18 months after brachytherapy correlated with the occurrence of prostate-specific antigen bounce. A multivariate analysis identified the intercourse satisfaction domain score 18 months after brachytherapy as an independent indicator for the occurrence of prostate-specific antigen bounce (P = 0.008).

CONCLUSIONS

International Index of Erectile Function-15 score seems to be correlated with the prostate-specific antigen bounce in prostate cancer patients undergoing brachytherapy, and an occurrence of prostate-specific antigen bounce seems to be more likely in those who are more sexually active.

Three-dimensional conformal arc radiotherapy using a C-arm linear accelerator with a computed tomography on-rail system for prostate cancer: clinical outcomes

Background

We report the feasibility and treatment outcomes of image-guided three-dimensional conformal arc radiotherapy (3D-CART) using a C-arm linear accelerator with a computed tomography (CT) on-rail system for localized prostate cancer.

Methods and materials

Between 2006 and 2011, 282 consecutive patients with localized prostate cancer were treated with in-room CT-guided 3D-CART. Biochemical failure was defined as a rise of at least 2.0 ng/ml beyond the nadir prostate-specific antigen level. Toxicity was scored according to the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.0.

Results

A total of 261 patients were analyzed retrospectively (median follow-up: 61.6 months). The median prescribed 3D-CART dose was 82 Gy (2 Gy/fraction, dose range: 78–86 Gy), and 193 of the patients additionally received hormonal therapy. The 5-year overall survival rate was 93.9 %. Among low-, intermediate-, and high-risk patients, 5-year rates of freedom from biochemical failure were 100, 91.5 and 90.3 %, respectively. Rates of grade 2–3 late gastrointestinal and genitourinary toxicities were 2.3 and 11.4 %, respectively. No patient experienced late grade 4 or higher toxicity.

Conclusions

In-room CT-guided 3D-CART was feasible and effective for localized prostate cancer. Treatment outcomes were comparable to those previously reported for intensity-modulated radiotherapy.

Comparison of genitourinary and gastrointestinal toxicity among four radiotherapy modalities for prostate cancer: Conventional radiotherapy, intensity-modulated radiotherapy, and permanent iodine-125 implantation with or without external beam radiotherapy

PURPOSE

To compare late genitourinary (GU) and gastrointestinal (GI) toxicity following different prostate cancer treatment modalities.

MATERIALS AND METHODS

This study included 1084 consecutive prostate cancer patients treated with conventional radiotherapy, intensity-modulated radiotherapy (IMRT), permanent iodine-125 implantation (PI) alone, and PI combined with external beam radiotherapy (PI+EBRT). The effects of treatment- and patient-related factors on late grade ⩾ 2 (G2+) GU/GI toxicity risk were assessed.

RESULTS

The median follow-up was 43 months (range, 12-97 months). Compared to the PI+EBRT, there was significantly less G2+ GU toxicity in the conventional radiotherapy (hazard ratio [HR] = 0.39; 95% CI, 0.20-0.77) and the IMRT (HR=0.45, 95% CI, 0.27-0.73). Compared to the PI+EBRT, there was significantly more G2+ GI toxicity in the IMRT (HR = 2.38; 95% CI, 1.16-4.87). In PI-related groups, prostate equivalent dose in 2 Gy fractions was a significant predictor of G2+ GU toxicity (p = 0.001), and the rectal volume receiving more than 100% of the prescribed dose was a significant predictor of G2+ GI toxicity (p = 0.001).

CONCLUSION

The differences in the late G2+ GU/GI risk cannot be explained by the differences in treatment modalities themselves, but by the total radiation dose to the GU/GI tract, which had a causal role in the development of late G2+ GU/GI toxicity across all treatment modality groups.

Dosimetric variations due to interfraction organ deformation in cervical cancer brachytherapy

We quantitatively estimated dosimetric variations due to interfraction organ deformation in multi-fractionated high-dose-rate brachytherapy (HDRBT) for cervical cancer using a novel surface-based non-rigid deformable registration. As the number of consecutive HDRBT fractions increased, simple addition of dose-volume histogram parameters significantly overestimated the dose, compared with distribution-based dose addition.

Combination of 5α-reductase inhibitor with combined androgen blockade (CAB) as a novel cytoreductive regimen before prostate brachytherapy: Ultra-CAB

We report a first case of using a 5α-reductase inhibitor (5ARI) and combined androgen blockade (CAB) as a cytoreductive regimen before prostate brachytherapy. Prostate volume reduction with CAB is limited to approximately 40% in most cases, making it difficult to meet anatomical constraints to perform these procedures in cases with large prostate volume. With the added administration of 5ARI, further volume reduction can be expected. Here, we describe this cytoreductive regimen used in a 63 year-old prostate cancer patient who became eligible to receive brachytherapy after dutasteride (0.5 mg daily) was added to CAB and prostate volume reduction of 57% was achieved.