In Curative Stereotactic Body Radiation Therapy for Prostate Cancer, There Is a High Possibility That 45 Gy in Five Fractions Will Not Be Tolerated without a Hydrogel Spacer

The purpose of this study was to determine the maximum tolerated dose (MTD) for stereotactic body radiation therapy (SBRT) in the treatment of non-metastatic prostate cancer. This study was a phase 1 dose escalation trial conducted in Japan. Patients with histologically proven prostate cancer without lymph nodes or distant metastases were enrolled. The prescribed doses were 42.5, 45, or 47.5 Gy in five fractions. Dose-limiting toxicity (DLT) was defined as grade (G) 3+ gastrointestinal or genitourinary toxicity within 180 days after SBRT completion, and a 6 plus 6 design was used as the method of dose escalation. A total of 16 patients were enrolled, with 6 in the 42.5 Gy group and 10 in the 45 Gy group. No DLT was observed in the 42.5 Gy group. In the 45 Gy group, one patient experienced G3 rectal hemorrhage, and another had G4 rectal perforation, leading to the determination of 42.5 Gy as the MTD. None of the patients experienced biochemical recurrence or death during the follow-up period. We concluded that SBRT for non-metastatic prostate cancer at 42.5 Gy in five fractions could be safely performed, but a total dose of 45 Gy increased severe toxicity.

Initial validation of a diaphragm tracking system for multiple breath-hold volumetric modulated arc therapy of abdominal tumors: A phantom study

BACKGROUND

The breath-hold radiotherapy has been increasingly used to mitigate interfractional and intrafractional breathing impact on treatment planning and beam delivery. Previous techniques include body surface measurements or radiopaque metal markers, each having known disadvantages.

PURPOSE

We recently proposed a new markerless technique without the disadvantages, where diaphragm was registered between DRR and fluoroscopic x-ray projection images every 180 ms during VMAT delivery. An initial validation of the proposed diaphragm tracking system (DiaTrak) was performed using a chest phantom to evaluate its characteristics.

METHODS

Diaphragm registration was performed between DRR and projection streaming kV x-ray images of a chest phantom during VMAT delivery. Streaming data including the projection images and the beam angles were transferred from a linac system to an external PC, where the diaphragm registration accuracy and beam-off latency were measured based on image cross correlation between the DRR and the projection images every 180 ms.

RESULTS

It was shown that the average of the beam-off latency was 249.5 ms and the average of the diaphragm registration error was 0.84 mm CONCLUSIONS: Initial validation of the proposed DiaTrak system for multiple breath-hold VMAT of abdominal tumors has been successfully completed with a chest phantom. The resulting beam-off latency and the diaphragm registration error were regarded clinically acceptable.

Long-term geometric quality assurance of radiation focal point and cone-beam computed tomography for Gamma Knife radiosurgery system

To investigate the geometric accuracy of the radiation focal point (RFP) and cone-beam computed tomography (CBCT) over long-term periods for the ICON Leksell Gamma Knife radiosurgery system. This phantom study utilized the ICON quality assurance tool plus, and the phantom was manually set on the patient position system before the implementation of treatment for patients. The deviation of the RFP position from the unit center point (UCP) and the positions of the four ball bearings (BBs) in the CBCT from the reference position were automatically analyzed. During 544 days, a total of 269 analyses were performed on different days. The mean ± standard deviation (SD) of the deviation between measured RFP and UCP was 0.01 ± 0.03, 0.01 ± 0.03, and -0.01 ± 0.01 mm in the X, Y, and Z directions, respectively. The deviations with offset values after the cobalt-60 source replacement (0.00 ± 0.03, -0.01 ± 0.01, and -0.01 ± 0.01 mm in the X, Y, and Z directions, respectively) were significantly (p = 0.001) smaller than those before the replacement (0.02 ± 0.03, 0.02 ± 0.01, and -0.02 ± 0.01 mm in the X, Y, and Z directions, respectively). The overall mean ± SD of four BBs was -0.03 ± 0.03, -0.01 ± 0.05, and 0.01 ± 0.03 mm in the X, Y, and Z directions, respectively. Geometric positional accuracy was ensured to be within 0.1 mm on most days over a long-term period of more than 500 days.

Curative Radiotherapy for Oropharyngeal Squamous Cell Carcinoma Stratified by p16 Status, According to the Eighth Edition American Joint Committee on Cancer Staging Manual: A Retrospective Study

Background/Aim

The prevalence of oropharyngeal squamous cell carcinoma (OPSCC) is increasing worldwide. This retrospective study aimed to investigate the clinical outcomes of patients with OPSCC undergoing definitive radiotherapy, stratified according to their p16 status.

Patients and Methods

A retrospective analysis was conducted on consecutive patients with OPSCC treated with curative external beam radiotherapy between May 2015 and September 2023. Clinical staging was determined by the eighth edition AJCC staging manual for p16 positive and negative OPSCC. All patients were treated with radiotherapy using a simultaneous integrated boost (SIB) with helical tomotherapy. The fractionation scheme, with or without chemotherapy, for the primary site and nodal lesions consisted of 2 Gy per fraction for a total dose of 70 Gy in 35 fractions over seven weeks.

Results

This study included 76 patients with a median age of 66 years. With a median follow-up time of 32.6 months, the 3-year progression-free survival rate was significantly higher in p16 positive patients compared to p16 negative patients (79.6% vs. 42.5%, p<0.001). Concerning 54 patients with p16-positive tumors, the overall survival rates indicated excellent clinical outcomes for stage I, II, and III with results of 100%, 100%, and 88.1%, respectively.

Conclusion

This retrospective study revealed the clinical outcomes of patients with OPSCC treated with radical radiotherapy, emphasizing the significance of p16 status. While acknowledging the limitations of the retrospective nature of this study, future prospective studies with larger cohorts and extended follow-up periods are needed to enhance evidence quality.

Central Neurocytoma Treated Using Supratentorial Ventricle Radiotherapy: A Single-Institution Analysis of Five Cases in Adjuvant or Salvage Settings After Surgery

INTRODUCTION

Central neurocytoma (CN) is an extremely rare tumor primarily located in the supratentorial ventricular system, categorized as a glioneuronal or neuronal tumor.

METHODS

This study presented a retrospective analysis of five CN patients who received adjuvant or salvage radiotherapy. Patients, aged 31-59 years, underwent radiation doses ranging from 60 Gy to 50.4 Gy over 27-30 fractions.

RESULTS

All patients achieved effective local tumor control without severe complications. The median follow-up period was 51.7 months, demonstrating 100% overall and progression-free survival rates.

DISCUSSION

Our study's clinical outcomes align with previous research, despite the limitation of a small sample size. Emphasizing the necessity for additional research, our findings added to the potential evidence of radiotherapy in managing CN. Larger, long-term studies were needed to confirm these promising results.

Relationship between hydrogel spacer distribution and dosimetric parameters in linear-accelerator-based stereotactic body radiotherapy for prostate cancer

PURPOSE

To explore the potential of quantitative parameters of the hydrogel spacer distribution as predictors for separating the rectum from the planning target volume (PTV) in linear-accelerator-based stereotactic body radiotherapy (SBRT) for prostate cancer.

METHODS

Fifty-five patients underwent insertion of a hydrogel spacer and were divided into groups 1 and 2 of the PTV separated from and overlapping with the rectum, respectively. Prescribed doses of 36.25-45 Gy in five fractions were delivered to the PTV. The spacer cover ratio (SCR) and hydrogel-implant quality score (HIQS) were calculated.

RESULTS

Dosimetric and quantitative parameters of the hydrogel spacer distribution were compared between the two groups. For PTV, D99% in group 1 (n = 29) was significantly higher than that in group 2 (n = 26), and Dmax , D0.03cc , D1cc , and D10% for the rectum were significantly lower in group 1 than in group 2. The SCR for prostate (89.5 ± 12.2%) in group 1 was significantly higher (p < 0.05) than that in group 2 (74.7 ± 10.3%). In contrast, the HIQS values did not show a significant difference between the groups. An area under the curve of 0.822 (95% confidence interval, 0.708-0.936) for the SCR was obtained with a cutoff of 93.6%, sensitivity of 62.1%, and specificity of 100%.

CONCLUSIONS

The SCR seems promising to predict the separation of the rectum from the PTV in linear-accelerator-based SBRT for prostate cancer.

Radiotherapy in nonagenarian patients: A 20-year retrospective analysis in a single ternary centre

INTRODUCTION

The global burden of cancer and the ageing population is increasing, resulting in an increase in cancer incidence among elderly patients. This study aimed to evaluate the clinical outcomes and safety profile of radiotherapy in nonagenarians and to contribute to the existing knowledge on radiotherapy in elderly patients.

METHODS

This retrospective analysis included nonagenarian patients who received external beam radiotherapy at a single centre in Japan between May 2003 and May 2023. Data, including patient demographics, tumour characteristics, treatment details, and clinical outcomes, were collected from medical records. Statistical analyses including survival and subgroup analyses were performed to summarize the data.

RESULTS

The analysis included 124 nonagenarian patients who received 151 treatment courses. Among the patients with a median age of 92 years (range, 90-98 years), 71 received palliative-intent radiotherapy and 53 underwent curative-intent radiotherapy. The overall survival rates at 1 and 3 years after radiotherapy were 55.4% and 38.3%, respectively. Performance status and radiotherapy at the primary site were independent prognosis factors for improved overall survival, while age was not. The incidence rate of grades 3-5 radiation-related toxicities was 3.4%, which is generally considered to be acceptable.

CONCLUSION

This study demonstrates that radiotherapy can be effectively and safely used in this age group, supporting its use as a treatment option for both palliative and curative goals. These results contribute to the existing body of evidence on radiotherapy in elderly patients and can guide clinical decision-making in the management of nonagenarian patients with cancer.

Clinical Outcomes of Curative Intent Radiotherapy by Helical Tomotherapy for Laryngeal Squamous Cell Carcinoma: A Retrospective Analysis in a Tertiary Referral Center

Background

The management of laryngeal cancer involves balancing curative treatment with preserving essential functions. This study aimed to evaluate the clinical outcomes of helical tomotherapy, an advanced form of radiation therapy, as a primary treatment modality for laryngeal squamous cell carcinoma (LSCC).

Methods

A retrospective analysis of data obtained from a tertiary referral center was performed to assess treatment response rates, survival outcomes, disease control, and treatment-related adverse events.

Results

The study included 45 patients with LSCC treated with helical tomotherapy between May 2015 and September 2022. The 5-year overall survival (OS) rate and disease-free survival (DFS) rate were 89.2% and 71.1%, respectively. Local control and laryngeal preservation rates at 5 years were 79.7% and 84.7%, respectively. Subgroup analysis revealed higher DFS rates in early-stage patients (84.2%) compared to advanced-stage patients (58.9%).

Conclusions

The results indicate that helical tomotherapy offers effective tumor control and potential for laryngeal preservation in LSCC. Further prospective studies and longer follow-up are needed to validate these findings and optimize treatment strategies for LSCC patients.

Complete remission of perineal extra-mammary Paget's disease by curative-intent radiotherapy using volumetric modulated arc therapy in a patient older than 90 years

ABSTRACT

Localized extra-mammary Paget's disease (EMPD) is mainly treated with surgical resection. Curative radiation therapy (CRT) is an alternative to surgery. Electron beams and conventional X-ray methods have been used in patients with EMPD for radiotherapy. The present report describes the case of a very elderly patient with perineal EMPD who was treated with definitive radiotherapy consisting of 60 Gy in 30 fractions. Surgery was deemed too difficult because of his age and comorbidities. We adopted volumetric modulated arc therapy as the radiotherapy modality, a recent, advanced form of intensity-modulated radiation therapy. Grade 3 dermatitis was observed as an acute phase adverse event, and he achieved a complete response and maintained remission for over one-year post-treatment. Our radiotherapy treatment protocol resulted in good clinical outcomes; therefore, it may be a candidate for inoperable patients with EMPD.

Six-year outcomes of robot-assisted radical prostatectomy versus volumetric modulated arc therapy for localized prostate cancer: A propensity score-matched analysis

BACKGROUND

Although robot-assisted radical prostatectomy (RARP) and intensity-modulated radiotherapy are the leading respective techniques of prostatectomy and radiotherapy for localized prostate cancer, almost no study has directly compared their outcomes; none have compared mortality outcomes.

METHODS

We compared 6‑year outcomes of RARP (n = 500) and volumetric modulated arc therapy (VMAT, a rotational intensity-modulated radiotherapy, n = 360) in patients with cT1-4N0M0 prostate cancer. We assessed oncological outcomes, namely overall survival (OS), cancer-specific survival (CSS), radiological recurrence-free survival (rRFS), and biochemical recurrence-free survival (bRFS), using propensity score matching (PSM). We also assessed treatment-related complication outcomes of prostatectomy and radiotherapy.

RESULTS

The median follow-up duration was 79 months (> 6 years). PSM generated a matched cohort of 260 patients (130 per treatment group). In the matched cohort, RARP and VMAT showed equivalent results for OS, CSS, and rRFS: both achieved excellent 6‑year outcomes for OS (> 96%), CSS (> 98%), and rRFS (> 91%). VMAT had significantly longer bRFS than RARP, albeit based on different definitions of biochemical recurrence. Regarding complication outcomes, patients who underwent RARP had minimal (2.6%) severe perioperative complications and achieved excellent continence recovery (91.6 and 68.8% of the patients achieved ≤ 1 pad/day and pad-free, respectively). Patients who underwent VMAT had an acceptable rate (20.0%) of grade ≥ 2 genitourinary complications and a very low rate (4.4%) of grade ≥ 2 gastrointestinal complications.

CONCLUSION

On the basis of PSM after a 6-year follow-up, RARP and VMAT showed equivalent and excellent oncological outcomes, as well as acceptable complication profiles.

Cone-beam computed-tomography-based delta-radiomic analysis for investigating prognostic power for esophageal squamous cell cancer patients undergoing concurrent chemoradiotherapy

PURPOSE

To investigate the prognostic power of cone-beam computed-tomography (CBCT)-based delta-radiomics in esophageal squamous cell cancer (ESCC) patients treated with concurrent chemoradiotherapy (CCRT).

METHODS

We collected data from 26 ESCC patients treated with CCRT. CBCT images acquired at five time points (1st-5th week) per patient during CCRT were used in this study. Radiomic features were extracted from the five CBCT images on the gross tumor volumes. Then, 17 delta-radiomic feature sets derived from five types of calculations were obtained for all the cases. Leave-one-out cross-validation was applied to investigate the prognostic power of CBCT-based delta-radiomic features. Feature selection and construction of a prediction model using Coxnet were performed using training samples. Then, the test sample was classified into high or low risk in each cross-validation fold. Survival analysis for the two groups were performed to evaluate the prognostic power of the extracted CBCT-based delta-radiomic features.

RESULTS

Four delta-radiomic feature sets indicated significant differences between the high- and low-risk groups (p < 0.05). The highest C-index in the 17 delta-radiomic feature sets was 0.821 (95 % confidence interval, 0.735-0.907). That feature set had p-value of the log-rank test and hazard ratio of 0.003 and 4.940 (95 % confidence interval, 1.391-17.544), respectively.

CONCLUSIONS

We investigated the potential of using CBCT-based delta-radiomics for prognosis of ESCC patients treated with CCRT. It was demonstrated that delta-radiomic feature sets based on the absolute value of relative difference obtained from the early to the middle treatment stages have high prognostic power for ESCC.

Prognostic value of radiomic features in patients with esophageal cancer treated with chemoradiotherapy

BACKGROUND

The aim of the present study was to evaluate the prognostic value of radiomic features in patients who underwent chemoradiotherapy for esophageal cancer.

METHODS

In this retrospective study, two independent cohorts of esophageal cancer patients treated with chemoradiotherapy were included. Radiomics features of each patient were extracted from pre-treatment computed tomography (CT) images. Radiomic features were selected by employing univariate and multivariate analyses in the test cohort. Selected radiomic features were verified in the validation cohort. The endpoint of the present study was overall survival.

RESULTS

A total of 101 esophageal cancer patients were included in our study, with 71 patients in the test cohort and 30 patients in the validation cohort. Univariate analysis identified 158 radiomic features as prognostic factors for overall survival in the test cohort. A multivariate analysis revealed that root mean squared and Low-High-High (LHH) median were prognostic factors for overall survival with a hazard ratio of 2.23 (95% confidence interval [CI]: 1.16-4.70, P = 0.017) and 0.26 (95% CI: 0.13-0.54, P < 0.001), respectively. In the validation cohort, root mean squared high/LHH median low group had the most preferable prognosis with a median overall survival of 73.30 months (95% CI: 32.13-NA), whereas root mean squared low/LHH median low group had the poorest prognosis with a median overall survival of 9.72 months (95% CI: 2.50-NA), with a P value of < 0.001.

CONCLUSIONS

We identified two radiomic features that might be independent prognostic factors of overall survival of esophageal cancer patients treated with chemoradiotherapy.

Hypofractionated Radiotherapy as a Standalone Treatment Modality for Locally Advanced Type B2 Thymoma in an Octogenarian Patient: 45 Gy in 15 Fractions

Thymic epithelial tumors (TETs), particularly type B2 thymomas, are rare neoplasms primarily found in the anterior mediastinum. The current therapeutic approach includes surgery, chemotherapy, and radiotherapy, but there is limited research on radiotherapy as a standalone treatment. This case report aims to elucidate the clinical outcomes of hypofractionated radiotherapy as a standalone treatment for locally advanced type B2 thymoma, offering insights into its potential efficacy and role in clinical practice.

Risk factors for local recurrence of keloids and hypertrophic scars after postoperative electron beam radiotherapy

OBJECTIVE

Keloids and hypertrophic scars are benign fibroproliferative lesions that occur as a result of skin injury. Postoperative radiation therapy is used to reduce the recurrence rate because of the high recurrence rate with surgical treatment alone. This study aimed to identify the risk factors for recurrence after postoperative electron beam radiotherapy.

MATERIALS AND METHODS

Patients with keloid or hypertrophic scars with at least one lesion and who underwent postoperative electron beam radiotherapy at our institution from June 2013 to March 2022 were included in the study, while patients with a follow-up period of fewer than three months were excluded.

RESULTS

A retrospective analysis was performed on 94 lesions in 81 patients. Exactly two years after the treatment, the actuarial local control rate was 86.4%. The chest wall, shoulder, and suprapubic area were identified as high-risk recurrence sites. Compared to other body sites, these sites had significantly lower local control rates (two-year local control rates: 75.5% vs. 95.2%, P = 0.005). After multivariate analysis, treatment site (P = 0.014), male gender (P = 0.019), and younger age (P = 0.029) were revealed to be statistically significant risk factors for local recurrence. Risk factors for keloid recurrence after postoperative electron beam radiotherapy were therefore identified.

CONCLUSION

This result could be used for follow-up and as a determinant for the optimal dose/fractionation of postoperative radiotherapy.

Survival Following Palliative Radiotherapy for Head and Neck Squamous Cell Carcinoma: Examining Treatment Indications in Elderly Patients

Background/Aim

This study investigated the survival outcomes of patients with head and neck squamous cell carcinoma (HNSCC) undergoing palliative radiotherapy, particularly focusing on challenges and factors associated with older age, providing insights into appropriate palliative radiotherapy use in this demographic.

Patients and Methods

A retrospective study was conducted using electronic medical records of 73 patients with HNSCC who were deemed unsuitable for curative therapy. Palliative radiotherapy involved a uniform dose of 30 Gy in 10 fractions. Survival analysis was performed using Kaplan-Meier method, and multivariate analysis identified significant prognostic factors.

Results

The median overall survival was 7.5 months, with no significant difference between age groups. Karnofsky performance status (KPS) >70 correlated with favorable survival. Multivariate analysis confirmed KPS as an independent prognostic factor (hazard ratio=1.949, p=0.031).

Conclusion

The results of this study align with those of previous studies, emphasizing the importance of palliative radiotherapy for HNSCC treatment. Optimal dose fractionation regimens remain undetermined, and tailored approaches that consider factors, such as age and performance status are crucial. Individualized, comprehensive assessments and supportive care measures enhance patient well-being, reflecting palliative care principles.

Prostate-specific antigen doubling time predicts the efficacy of site-directed therapy for oligoprogressive castration-resistant prostate cancer

Background

In recent years, site-directed therapies (SDTs) targeting progressive lesions in patients with oligometastatic prostate cancer have attracted attention. However, whether they effectively treat oligoprogressive castration-resistant prostate cancer (CRPC) remains unclear. Here, we investigated the efficacy of SDT in patients with oligoprogressive CRPC and identified prognostic factors.

Methods

We reviewed 59 patients with oligoprogressive CRPC who underwent SDT targeting prostate or metastatic lesions between April 2014 and March 2022. We evaluated the associations between several pretreatment clinical variables and treatment procedures and a >50% prostate-specific antigen (PSA) response, progression-free survival (PFS), and time to next treatment (TTNT).

Results

A PSA response of >50% was observed in 66% of patients. The median PFS and TTNT were 8.3 months and 9.9 months, respectively. Patients with PSA doubling time ≥6 months showed a higher >50% PSA response rate (87% vs. 45%; P < 0.001), longer PFS (median, 15.0 vs. 5.0 months; P < 0.001), and longer TTNT (median, 16.3 vs. 5.9 months; P < 0.001) than patients with PSA doubling time <6 months. In multivariate analyses, a PSA doubling time of ≥6 months independently predicted a >50% PSA response, favorable PFS, and TTNT (P = 0.037, 0.025, and 0.017, respectively).

Conclusion

PSA doubling time of ≥6 months may be a key indicator of the favorable efficacy of SDT for oligoprogressive CRPC.

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.

Adjuvant Radiotherapy for Major Salivary Gland Malignancies: Impact on Locoregional Control and Survival Outcomes

BACKGROUND/AIM

This study aimed to assess the effect of adjuvant radiotherapy on locoregional control, disease-free survival, and overall survival rates in patients with major salivary gland malignancies. The study also aimed to provide findings to guide clinicians in selecting appropriate candidates for adjuvant radiotherapy and optimizing treatment strategies for this challenging disease.

PATIENTS AND METHODS

A retrospective single-center analysis was conducted, reviewing the medical records of patients diagnosed with major salivary gland malignancies between November 2008 and May 2023. Inclusion criteria were histologically confirmed malignancy, surgical resection of the primary tumor, adjuvant radiotherapy, and availability of clinical and follow-up data. Survival analyses were performed using the Kaplan-Meier method, and Cox proportional hazards regression models were used to assess survival outcomes.

RESULTS

The study included 37 patients with major salivary gland malignancies. The most common site was the parotid gland, and the predominant histopathological diagnosis was salivary duct carcinoma. Adjuvant radiotherapy was generally well-tolerated, with the most common acute toxicities being grade 1-2 mucositis and dermatitis. The 5-year overall survival and progression-free survival rates were 93.8% and 62.9%, respectively. Locoregional control rate at five years was 89.1%. Recurrence occurred in 12 patients, with most cases observed within two years from the start of adjuvant radiotherapy. Distant metastasis was observed in nine patients.

CONCLUSION

This retrospective analysis highlights the positive impact of adjuvant radiotherapy on locoregional control and survival outcomes in major salivary gland malignancies. The findings contribute to the existing body of evidence, aiding clinicians in treatment decision-making and potentially informing future prospective studies and treatment guidelines for this challenging disease.

Efficacy and Safety of Bladder Preservation Therapy in Combination with Atezolizumab and Radiation Therapy (BPT-ART) for Invasive Bladder Cancer: Interim Analysis from a Multicenter, Open-label, Prospective Phase 2 Trial

PURPOSE

To evaluate the safety and pathologic complete response (pCR) rate of radiation therapy with atezolizumab as bladder-preserving therapy for invasive bladder cancer.

METHODS AND MATERIALS

A multicenter, phase 2 study was conducted with patients with clinically T2-3 or very-high-risk T1 bladder cancer who were poor candidates for or refused radical cystectomy. The interim analysis of pCR is reported as a key secondary endpoint ahead of the progression-free survival rate primary endpoint. Radiation therapy (41.4 Gy to the small pelvic field and 16.2 Gy to the whole bladder) was given in addition to 1200 mg intravenous atezolizumab every 3 weeks. After 24 treatment weeks, response was assessed after transurethral resection, and tumor programmed cell death ligand-1 (PD-L1) expression was assessed using tumor-infiltrating immune cell scores.

RESULTS

Forty-five patients enrolled from January 2019 to May 2021 were analyzed. The most common clinical T stage was T2 (73.3%), followed by T1 (15.6%) and T3 (11.1%). Most tumors were solitary (77.8%), small (<3 cm) (57.8%), and without concurrent carcinoma in situ (88.9%). Thirty-eight patients (84.4%) achieved pCR. High pCR rates were achieved in older patients (90.9%) and in patients with high PD-L1-expressing tumors (95.8% vs 71.4%). Adverse events (AEs) occurred in 93.3% of patients, with diarrhea being the most common (55.6%), followed by frequent urination (42.2%) and dysuria (20.0%). The frequency of grade 3 AEs was 13.3%, whereas no grade 4 AEs were observed.

CONCLUSIONS

Combination therapy with radiation therapy and atezolizumab provided high pCR rates and acceptable toxicity, indicating it could be a promising option for bladder preservation therapy.

Thirty-day Mortality in Palliative Radiotherapy: A Retrospective Cohort Analysis in a Single Center

Background/Aim

Palliative radiotherapy is a critical component of cancer care aimed at symptom management and enhancing the quality of life of patients with advanced cancer. Balancing symptom relief and potential risks is pivotal in clinical decision-making. This study explored the 30-day mortality (30-DM) rate after palliative radiotherapy in a single-center setting to shed light on potential prognostic factors and safety considerations.

Patients and Methods

This retrospective cohort study included patients who underwent palliative radiotherapy for various indications between March 2020 and February 2023. Data were retrieved from electronic medical records and analyzed according to ethical guidelines. The primary outcome measure was 30-DM rate, and multivariate logistic regression analysis was conducted to identify the independent predictors of 30-DM.

Results

A total of 931 palliative radiotherapy sessions were administered to 601 patients, with a median of one session per patient. The cohort had a median age of 70 years, predominantly men (58%), and featured diverse primary cancer types, with lung cancer being the most prevalent (15.8%). The 30-DM rate was 12.9%. Multivariate analysis identified Karnofsky Performance Status (KPS) as the sole independent prognostic factor significantly associated with 30-DM.

Conclusion

This study provides valuable insights into 30-DM rates following palliative radiotherapy. Future research should focus on prospective multicenter investigations with larger cohorts and comprehensive data collection, ultimately leading to improved risk prediction models for personalized treatment decisions in palliative radiotherapy.

Failure Patterns of Recurrence in Patients With Localized Esthesioneuroblastoma Following Surgery and Adjuvant Radiotherapy Without Elective Nodal Irradiation

BACKGROUND

Esthesioneuroblastoma (ENB), a rare malignancy arising from the olfactory epithelium, poses clinical challenges owing to its propensity for local invasion and recurrence. Its management typically involves surgical resection and adjuvant radiotherapy. However, debate persists regarding the optimal treatment strategy, particularly the use of elective nodal irradiation (ENI). This study aimed to investigate recurrence patterns in patients with localized ENB treated with surgery and adjuvant radiotherapy without ENI.

METHODS

Our retrospective analysis included patients who underwent surgery followed by adjuvant radiotherapy for treatment of ENB between January 2011 and November 2022. Patients with incomplete data or who had received neoadjuvant radiotherapy were excluded. Patient characteristics, radiotherapy data (type, dose, and duration), and follow-up data were collected. Recurrence patterns were evaluated, and overall survival (OS), disease-free survival (DFS), and local control rates were determined using the Kaplan-Meier method.

RESULTS

Twelve patients with ENB (median age, 56 years) were included. Most had stage C disease. The median radiation dose was 60 Gy, and the median treatment duration was six weeks. Only one death was confirmed during the observation period, and the five-year DFS rates were 64.3%. Local control was achieved in 11 patients, with only one experiencing local recurrence. Regional lymph node recurrence occurred in three patients and was successfully managed via neck dissection. The timing of recurrence varied, emphasizing the importance of long-term surveillance.

CONCLUSION

Adjuvant radiotherapy without ENI is a viable treatment option for ENB, resulting in favorable local control and OS outcomes. Regional lymph node metastases were observed but effectively managed via salvage therapy. Prospective studies with larger cohorts are warranted to confirm the effectiveness of this treatment strategy and to define optimal radiotherapy fields.

Real-World Results of Stereotactic Body Radiotherapy for 399 Medically Operable Patients with Stage I Histology-Proven Non-Small Cell Lung Cancer

Surgery is the standard treatment for stage I non-small cell lung cancer (NSCLC); however, no clear randomized trial demonstrates its superiority to stereotactic body radiotherapy (SBRT) regarding survival. We aimed to retrospectively evaluate the treatment outcomes of SBRT in operable patients with stage I NSCLC using a large Japanese multi-institutional database to show real-world outcome. Exactly 399 patients (median age 75 years; 262 males and 137 females) with stage I (IA 292, IB 107) histologically proven NSCLC (adenocarcinoma 267, squamous cell carcinoma 96, others 36) treated at 20 institutions were reviewed. SBRT was prescribed at a total dose of 48-70 Gy in 4-10 fractions. The median follow-up period was 38 months. Local progression-free survival rates were 84.2% in all patients and 86.1% in the T1, 78.6% in T2, 89.2% in adenocarcinoma, and 70.5% in squamous cell subgroups. Overall 3-year survival rates were 77.0% in all patients: 90.7% in females, 69.6% in males, and 41.2% in patients with pulmonary interstitial changes. Fatal radiation pneumonitis was observed in two patients, all of whom had pulmonary interstitial changes. This real-world evidence will be useful in shared decision-making for optimal treatment, including SBRT for operable stage I NSCLC, particularly in older patients.

Novel breath-hold liver target stereotactic ablative radiotherapy using the intrafraction diaphragm registration of kilovoltage projection streaming image with digitally reconstructed radiography of the planning computed tomography

Stereotactic ablative radiotherapy (SABR) is an emerging treatment option for patients with primary or metastatic liver tumors, particularly for those who are not eligible for surgery or transplantation. SABR is a high-precision radiation therapy that delivers a high dose of radiation to the tumor while minimizing the dose to the surrounding healthy tissues. However, the accurate targeting of the tumor is a crucial aspect of liver SABR, which requires real-time imaging and tracking of the liver and tumor motion during treatment. One of the motion management strategies for liver SABR is the repeated breath-hold technique, which involves the patient holding their breath multiple times during treatment delivery to reduce the movement of the liver and other organs due to breathing. This technique helps to improve the accuracy of the treatment and reduce the radiation dose to the healthy liver. The current study proposes a novel approach for multiple breath-hold volumetric modulated arc therapy (VMAT) stereotactic ablative radiotherapy for liver tumors, which uses the intrafraction diaphragm registration in real time to improve the accuracy and precision of the treatment. The proposed approach is based on real-time comparison of the diaphragmatic surface location between the digitally reconstructed radiography (DRR) and intrafraction kilovoltage projection streaming images (kV-PSI) having the same beam angles. The image cross-correlation between the DRR and the intrafraction kV-PSI provides a measure of the similarity between the two images and can be used to identify and track the diaphragm position during VMAT delivery. The proposed methodology consists of several steps, including planning CT and treatment planning, reference image reconstruction, and patient positioning and immobilization. The proposed approach has the potential to improve the accuracy and precision of liver cancer VMAT SABR, thereby increasing the efficacy of the treatment and reducing the risk of radiation exposure to surrounding healthy tissues.

Comparative Analysis of Photon Stereotactic Radiotherapy and Carbon-Ion Radiotherapy for Elderly Patients with Stage I Non-Small-Cell Lung Cancer: A Multicenter Retrospective Study

The emergence of an aging society and technological advances have made radiotherapy, especially stereotactic body radiotherapy (SBRT), a common alternative to surgery for elderly patients with early stage non-small-cell lung cancer (NSCLC). Carbon-ion radiotherapy (CIRT) is also an attractive treatment option with potentially lower toxicity for elderly patients with comorbidities. We compared the clinical outcomes of the two modalities using Japanese multicenter data. SBRT (n = 420) and single-fraction CIRT (n = 70) data for patients with stage I NSCLC from 20 centers were retrospectively analyzed. Contiguous patients ≥ 80 years of age were enrolled, and overall survival (OS), disease-specific survival (DSS), local control (LC), and adverse event rates were compared. The median age was 83 years in both groups and the median follow-up periods were 28.5 and 42.7 months for SBRT and CIRT, respectively. The 3-year OS, DSS, and LC rates were 76.0% vs. 72.3% (p = 0.21), 87.5% vs. 81.6% (p = 0.46), and 79.2% vs. 78.2% (p = 0.87), respectively, for the SBRT vs. CIRT groups. Regarding toxicity, 2.9% of the SBRT group developed grade ≥ 3 radiation pneumonitis, whereas none of the CIRT group developed grade ≥ 2 radiation pneumonitis. SBRT and CIRT in elderly patients showed similar survival and LC rates, although CIRT was associated with less severe radiation pneumonitis.

Retrospective comparison between definitive stereotactic body radiotherapy and radical surgery for 538 patients with early-stage non-small cell lung cancer in a single institution

Introduction

Survival information for stereotactic body radiotherapy (SBRT) and surgery for stage I non-small cell lung cancer (NSCLC) was examined.

Methods

Stage I NSCLC patients who underwent surgery or SBRT between 2012 and 2016 were retrospectively enrolled in this single-institution study. Using the Kaplan--Meier method and Cox regression model, overall survival (OS) was estimated and compared.

Results

Among 538 enrolled patients, compared to the surgery group (443), the SBRT group (95) had more complications (P = 0.01), worse performance status (P = 0.001), and were older (P < 0.001). Three-year OS was 70.5% post SBRT and 90.1% postsurgery. The 3-year cancer-specific survival (CSS) and disease-free survival (DFS) post SBRT and postsurgery were 92.7% vs. 92.3% and 61.1% vs 79.3%, respectively. Three-year locoregional and distant control rates post SBRT and postsurgery were 85.6% vs. 90.1% and 82.5% vs. 86.4%, respectively. Multivariate analysis using the Cox model, including age, T-stage, CCI, and C/T ratio and treatment, showed the surgery group's OS to be significantly superior to that of the SBRT group (HR of SBRT per surgery: 1.90, 95%CI: 1.12-3.21, P = 0.017). No significant differences were observed in rates of adverse events.

Conclusion

Although OS was better in the surgery group, no differences in CSS existed. This analysis suggests the need for future studies that compare specific radical surgeries and SBRT in a prospective and randomized setting.

Dosimetric Comparison Study Between Free Breathing and Breath Hold Techniques in Patients Treated by Liver-Directed Stereotactic Body Radiation Therapy

Background Breathing motion management is the key to delivering stereotactic body radiation therapy (SBRT) for liver lesions. This study aimed to compare the dosimetric parameters of liver SBRT using two different techniques: free breathing and breath hold. Method The study included 11 patients with liver metastases or hepatocellular carcinoma who underwent liver-directed SBRT. A dosimetric comparison was performed using dose-volume histogram analysis, evaluating parameters such as the maximum dose to 5 cc of bowel volume, mean liver dose (MLD), and liver V20 and V30. Statistical analyses were performed to compare results. Results The findings revealed that the breath hold technique resulted in significantly lower doses to the bowel and smaller volumes of normal liver tissue receiving 20 Gy (V20) and 30 Gy (V30) than the free breathing. Although there was no statistically significant difference in the MLD between the two techniques, the breath hold technique resulted in a lower MLD. Conclusion This dosimetric comparison study suggests that the breath hold technique is associated with lower radiation exposure to the bowel and normal liver tissues. Although this may not be feasible for all patients, it may be an appropriate procedure for selected individuals. Further research is needed to validate these findings in different patient populations and explore their impact on clinical outcomes and patient-reported quality of life.

Usefulness of palliative radiotherapy in reducing the frequency of red blood cell transfusion in patients with malignant tumor bleeding

Objective

We aimed to evaluate the usefulness of palliative radiotherapy in reducing the frequency of red blood cell (RBC) transfusions in patients with malignant tumor bleeding as a quantitative value to evaluate the hemostatic effect.

Materials and Methods

In this study, we conducted a retrospective review of patients visiting our department between June 2013 and April 2021. All patients underwent RBC transfusions for 30 days before the initiation of radiotherapy. We determined the overall survival (OS) time and RBC transfusion-free (RBCTF) time using statistical tests.

Results

In total, 21 patients were enrolled in our study, including 13 women and 8 men; the median patient age was 63 years (range: 32-82 years). After radiotherapy, 19 of the 21 patients had a decreased frequency of requirement for RBC transfusion compared to that before radiotherapy. Fourteen patients had achieved an RBCTF state 1 month after radiotherapy. The estimated 1-year OS and RBCTF rates were 36.3% (95% confidence interval [CI]: 14.2%) and 66.7% (95% CI: 42.5%-42.5%), respectively.

Conclusion

The present study revealed a reduction in RBC transfusion after palliative radiotherapy in patients with malignant tumor bleeding. We believe that reducing the frequency of blood transfusions in patients with terminal conditions would have significant clinical benefits.

Intractable Pleural Effusion After Stereotactic Ablative Radiotherapy for Early-Stage Lung Cancer

Stereotactic ablative radiotherapy (SABR) is an effective and attractive treatment option for patients who are poor surgical candidates. This case report describes a rare but serious complication of intractable pleural effusion after SABR for early-stage lung cancer. The patient was an 89-year-old woman with a medical history of early-stage breast cancer who was treated with partial resection and postoperative radiotherapy of 50 gray (Gy) in 25 fractions. SABR using 55 Gy in four fractions was conducted for lung lesions. The patient developed a pleural effusion that was refractory to conservative management and required multiple interventions, including repeated thoracentesis. This case report emphasizes the importance of monitoring and managing pleural effusion in patients with lung cancer receiving radiotherapy.

Definitive radiotherapy consisting of external beam radiotherapy without central shielding and 3D image-guided brachytherapy for patients with cervical cancer: feasibility for Japanese patients and dose-response analyses for local control in the low-dose range

OBJECTIVE

To assess the feasibility of external beam radiotherapy without central shielding in definitive radiotherapy for Japanese patients with cervical cancer.

METHODS

We retrospectively analysed the data of cervical cancer patients treated with definitive radiotherapy consisting of external beam radiotherapy without central shielding and three-dimensional-image-guided brachytherapy.

RESULTS

The study included 167 patients (T1 + 2 = 108, T3 + 4 = 59) from eight Japanese institutions. For three-dimensional-image-guided brachytherapy, intra-cavitary and interstitial brachytherapy was utilized in 33 patients (20%). The median follow-up was 26.6 months (interquartile range, 20-43.2). The maximum rectal D2 (75 Gy)/bladder D2 (90 Gy) constraints were deviated by 6%/10% and 10%/5% for T1 + 2 and T3 + 4, respectively. The 2-year incidence of ≥grade 3 proctitis/cystitis was 4%/1% for T1 + 2 and 10%/2% for T3 + 4. The 2-year local progression-free survival was 89% for T1 + 2 and 82% for T3 + 4. For T1 + 2, the 2-year local progression-free survival for the high-risk clinical target volume D90 ≥ 68 Gy (indicated by receiver operating characteristic analysis; area under the curve = 0.711) was 92% versus 67% for <68 Gy (log-rank; P = 0.019). Cox multivariate analysis indicated that the high-risk clinical target volume D90 was one of independent predictors of local failure (P = 0.0006). For T3 + 4, the 2-year local progression-free survival was 87% for the high-risk clinical target volume <82 cm3 (area under the curve = 0.67) and 43% for ≥82 cm3 (P = 0.0004). Only the high-risk clinical target volume was an independent predictor of local failure (P = 0.0024).

CONCLUSIONS

Definitive radiotherapy consisting of external beam radiotherapy without central shielding and three-dimensional-image-guided brachytherapy was feasible for Japanese patients with cervical cancer. Dose de-escalation from the current global standards is suggested for patients with T1 + 2 disease.

Long-Term Survival After Repeated Salvage Chemoradiation Therapy for Metastatic Lymph Node Recurrence in Advanced Gastric Cancer: A Case Report

Metastatic recurrence in advanced gastric cancer is a poor prognosis, and where recently novel systemic therapies have been investigated. This case report describes the successful use of repeated salvage chemoradiation therapy in a patient with advanced gastric cancer who had failed initial treatments. The patient achieved long-term survival and remained disease-free for several years after treatment. The report highlights the potential benefits of salvage chemoradiation therapy in selected patients with advanced gastric cancer and the need for further studies to determine the optimal treatment approach for these patients. The report also discusses recent promising results from clinical trials of combination regimens with immune checkpoint inhibitors and targeted therapies in the management of advanced gastric cancer. Overall, the report highlights the ongoing challenge of managing advanced gastric cancer and the importance of personalized treatment strategies.

An Invisible Skin Marker for External Beam Radiation Therapy: Utilization of Ultraviolet Fluorescent Marker Pens

Radiation therapy plays an important role in cancer treatment along with surgery and systemic therapy. The total dose of radiation therapy is divided into small doses, and the treatment is typically delivered once a day. The total treatment period can need several weeks or more, and it is necessary to deliver the radiation dose to the target volume within the patient precisely each time. Therefore, the reproducibility of patient positioning is essential for the precision of the dose delivery. Although radiological technologies such as image-guided radiation therapy have also recently been widely used for positioning patients, skin marking is still widely used in many facilities. Skin marking is an inexpensive and universal positioning technique in patients undergoing radiation therapy; however, it is considered a major source of psychological stress. We propose the use of fluorescent ink pens, which are invisible in standard room lighting, as skin markers for radiotherapy. The primary technique of fluorescence emission is widely employed in molecular biological experiments and for assessing cleaning protocols for infection control. This technique may reduce the stress induced by skin markings during radiotherapy.

Reduction of noise induced by power supply lines using phase-locked loop

An experimental implementation for the reduction of power-line noise in delicate signal detection is presented. This implementation improves the signal-to-noise ratio without limiting the bandwidth of the measurement. A sinusoidal wave and its harmonics, both synchronized with the frequency of the power line, are used to cancel out the power supply noise induced in the measurement signal. The wave and the harmonics are generated via a phase-locked loop implementation. Their amplitude and phase are adjusted, and then they are added to the measurement signal using a series of operational amplifiers to compensate for the noise. Although we applied this method to the particular case of scanning tunneling microscopy measurements, considerably improving the image quality, our implementation can be applied to other measurement systems for which noise from the power lines can compromise the signal detection.

Development of Japanese Cancer Intelligence Quotient to Measure Cancer Literacy and Knowledge among Japanese Laypersons

INTRODUCTION

Health literacy has been identified an essential factor in leading a healthy lifestyle. Because some cancer prevention and screening methods have been established, we believe that identifying disadvantaged populations with low literacy regarding cancer is crucial. Thus, in this study, we aim to create a self-administered cancer-specific health literacy scale to be administered to Japanese laypersons.

METHODS

Using definitions from previous studies, we constructed a scale named the Japanese Cancer Intelligence Quotient (JCIQ) for both literacy (JCIQ-L) and knowledge (JCIQ-K) aspects. We generated potential items for both aspects, extracted appropriate ones using two-step online surveys, and compared the JCIQ and cancer-preventive behaviors and cancer-screening intentions, both of which we set as alternative indicators of the right attitude and practice toward cancer by performing a multiple regression analysis from another web survey.

RESULTS

Between April and May 2020, we conducted three-step surveys online. After conducting the two-step surveys for thousands of people, we extracted 12 literacy questions and 22 knowledge questions using factor analysis and the correct answer ratio of every item. In the final investigation of 3,094 people, a multiple regression analysis found that the JCIQ-L and JCIQ-K were significant factors in terms of predicting both behaviors (JCIQ-L:β = 0.07, p < 0.001, JCIQ-K:β = 0.05, p < 0.01) and willingness (JCIQ-L:β = 0.04, p < 0.05, JCIQ-K:β = 0.17, p < 0.001) after adjusting for participant characteristics (e.g., gender, age, income level, employment status).

CONCLUSIONS

We developed the first reliable scale for measuring cancer literacy and knowledge of Japanese laypersons.

P-199 Effect of the area of oocyte perivitelline space on the fertilization and embryo development following intracytoplasmic sperm injection

Study question

Does the area of oocyte perivitelline space have an effect on fertilization and embryo development following intracytoplasmic sperm injection?

Summary answer

The area of oocyte perivitelline space has not an effect on the fertilization but the embryo development following intracytoplasmic sperm injection.

What is known already

Oocyte perivitelline space has a lot of variation at intracytoplasmic sperm injection (ICSI). Some researchers reported that the characteristics of perivitelline space (large or small) affect embryo development, pregnancy, and implantation. However, these studies did not accurately calculate the area of perivitelline space. Therefore, little information is available on the effect of the area of oocyte perivitelline space on fertilization and embryo development following ICSI. The purpose of this study was to calculate and classify the area of oocyte perivitelline space and investigate the effect of the area of perivitelline space on fertilization and embryo development following ICSI.

Study design, size, duration

1. We retrospectively investigated 634 mature oocytes that were conducted ICSI between January 2021 and December 2021. The area of each oocyte perivitelline space was defined from between the area of circle calculated from the inner layer of zona pellucida and cytoplasm and divided into 3 groups (-9%, 10-19%, 20%-).

2. We retrospectively calculated the diameter of an inner layer of zona pellucida and cytoplasm and compared it with the 3 groups (-9%, 10-19%, 20%-).

Participants/materials, setting, methods

1. The fertilization, survival, good quality day-3 embryo, blastocyst, good quality blastocyst rates following ICSI were compared with the 3 groups (-9%, 10-19%, 20%-).

2. The average diameter of an inner layer of zona pellucida and cytoplasm of each oocyte for the 3 groups (-9%, 10-19%, 20%-) were compared.

The data were analyzed by Fisher’s exact test, residual analysis, one-way ANOVA test, with Bonferroni correction as appropriate to determine the statistical differences among groups.

Main results and the role of chance

1. The survival rates of perivitelline space -9%, 10-19%, 20%- groups were 100% (109/109), 96% (363/378), 94% (138/147), the fertilization rates were 89% (97/109), 88% (331/378), 86% (127/147), the good quality day-3 embryo rates were 56% (54/97), 70% (232/331), 70% (89/127) respectively. No significant difference was observed between these comparison items. The blastocyst rates of perivitelline space -9%, 10-19%, 20%- groups were 51% (47/92), 69% (222/321), 82% (93/114), the good quality blastocyst rates were 22% (20/92), 40% (129/321), 52% (59/114) respectively. The blastocyst and good quality blastocyst rates of perivitelline space -9% group showed significantly lower results. On the other hand, the blastocyst and good quality blastocyst rates of perivitelline space 20%- group showed significantly higher results.

2. The average diameter of an inner layer of zona pellucida of perivitelline space -9%, 10-19%, 20%- groups were 125 ± 4 µm, 129 ± 5 µm, 136 ± 6 µm, the average diameter of the cytoplasm of perivitelline space were 121 ± 4 µm, 119 ± 4 µm, 118 ± 4 µm respectively. Significant differences were observed in all pairs of groups of the average diameter of an inner layer of zona pellucida and cytoplasm.

Limitations, reasons for caution

The area of oocyte perivitelline space was calculated at only one plane.

Wider implications of the findings

Oocytes with narrow perivitelline space might have a wide region of adhesive between the cytoplasm surface and an inner layer of the zona pellucida which resulted in a smaller diameter of the zona pellucida and lower blastocyst rate by forming cytoplasmic fragments (Yumoto K et al. JARG. 2020 ;37(6):1349-1354.).

Trial registration number

Not Applicable

The Spontaneous Remission of Recurrent Lymph Node Metastatic Prostate Cancer With Lowering Serum Prostate-Specific Antigen Level

The incidence rate of spontaneous remission of malignant cancer is very low. Reports on spontaneous remission in advanced prostate cancer are extremely limited. Our patient was treated with androgen deprivation therapy, local radiotherapy, and surgical castration at the initial diagnosis. Approximately nine years after treatment, he experienced a rise in serum prostate-specific antigen level and relapse of obturator lymph node adenopathy. Initially, androgen deprivation therapy was reinitiated, which resulted in castration-resistant prostate cancer. Although androgen deprivation therapy was discontinued, spontaneous remission of recurrent lymph node and spontaneous reduction in serum prostate-specific antigen level was seen. There was no sign of radiological recurrence for over eight years without prostate cancer treatment.

Quality of life after definitive linear accelerator-based stereotactic radiotherapy for prostate cancer: a longitudinal study

BACKGROUND

Prostate cancer is the second most common malignancy worldwide, and the majority of patients are diagnosed with localized disease. We examined patients' quality of life after stereotactic body radiation therapy (SBRT) for prostate cancer.

METHODS

We included patients who were treated between 2016 and 2020. Inclusion criteria were adenocarcinoma of the prostate; class risk of low, intermediate, and high; and a World Health Organization performance status of 0-2. Quality of life was measured using the Functional Assessment of Cancer Therapy-Prostate (FACT-P).

RESULTS

A total of 439 patients were treated with SBRT, with a median age of 73 years old. The median follow-up period was 34 months. FACT-P Trial Outcome Index (p < 0.0001), FACT-General (p = 0.0003), and FACT-P-Total (p < 0.0001) scores declined at 1 month post-SBRT, then recovered and returned to the same level as before treatment at 3-4 months post-SBRT. The decrease in quality of life in the first month was particularly remarkable in patients who received long-term hormone injections (36%). One month after the end of SBRT, about 22% of patients experienced "quite a bit" or more troubling side effects.

CONCLUSIONS

This study showed longitudinal changes in quality of life by FACT-P after SBRT for prostate cancer. Overall, prostate SBRT was well tolerated.

Training of deep cross-modality conversion models with a small dataset, and their application in megavoltage CT to kilovoltage CT conversion

PURPOSE

In recent years, deep-learning-based image processing has emerged as a valuable tool for medical imaging owing to its high performance. However, the quality of deep-learning-based methods heavily relies on the amount of training data; the high cost of acquiring a large dataset is a limitation to their utilization in medical fields. Herein, based on deep learning, we developed a computed tomography (CT) modality conversion method requiring only a few unsupervised images.

METHODS

The proposed method is based on CycleGAN with several extensions tailored for CT images, which aims at preserving the structure in the processed images and reducing the amount of training data. This method was applied to realize the conversion of megavoltage computed tomography (MVCT) to kilovoltage computed tomography (kVCT) images. Training was conducted using several datasets acquired from patients with head and neck cancer. The size of the datasets ranged from 16 slices (two patients) to 2745 slices (137 patients) for MVCT and 2824 slices (98 patients) for kVCT.

RESULTS

The required size of the training data was found to be as small as a few hundred slices. By statistical and visual evaluations, the quality improvement and structure preservation of the MVCT images converted by the proposed model were investigated. As a clinical benefit, it was observed by medical doctors that the converted images enhanced the precision of contouring.

CONCLUSIONS

We developed an MVCT to kVCT conversion model based on deep learning, which can be trained using only a few hundred unpaired images. The stability of the model against changes in data size was demonstrated. This study promotes the reliable use of deep learning in clinical medicine by partially answering commonly asked questions, such as "Is our data sufficient?" and "How much data should we acquire?" This article is protected by copyright. All rights reserved.

Cumulative Incidence and Clinical Risk Factors of Radiation Cystitis after Radiotherapy for Prostate Cancer

OBJECTIVES

This study aimed to evaluate the cumulative incidence of overall and severe radiation cystitis following external beam radiation therapy for prostate cancer and investigate the clinical factors predictive of radiation cystitis.

METHODS

This retrospective study comprised 246 patients who received external beam radiation therapy for localized or locally advanced prostate cancer between 2013 and 2016 in our institution. Of these, 189 received primary radiation therapy and 57 received adjuvant/salvage radiation therapy. Radiation cystitis was recorded using the Common Terminology Criteria for Adverse Events version 5.0 definition, and severe radiation cystitis was defined as grade 3 or higher. All medical records were reviewed to calculate the cumulative incidence of radiation cystitis. Univariate and multivariate Cox regression analyses were used to evaluate its association with clinicopathologic features.

RESULTS

The median follow-up period after radiation therapy was 56 months (range 5-81). The 5-year cumulative incidence of radiation cystitis and severe radiation cystitis was 16.2% and 3.0%, respectively. Multivariate analyses identified radiation therapy in the adjuvant/salvage setting was the sole risk factor associated with the development of radiation cystitis (hazard ratio: 2.75, p = 0.02).

CONCLUSIONS

Radiation therapy in the post-prostatectomy setting was associated with increased risk of radiation cystitis compared with radiotherapy as the primary treatment.

Stereotactic Body Radiotherapy for a Sacral Metastasis Clarified by Diffusion-Weighted Whole-Body Imaging With Background Body Signal Suppression in a Patient With Castration-Resistant Prostate Cancer

Diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) is an emerging extended modality of diffusion-weighted imaging for screening malignant lesions in the body. A 70-year-old male was diagnosed with advanced-stage prostate adenocarcinoma with distant metastasis. After hormone therapy, the disease progressed to castration-resistant prostate cancer (CRPC). Serum prostate-specific antigen (PSA) levels increased during androgen deprivation therapy with low serum testosterone levels. 18F-Fluorodeoxyglucose positron emission tomography (FDG-PET) and technetium-99m methylene bone scintigraphy (BS) did not reveal obvious distant metastases; however, we were able to identify distant metastases by DWIBS. We herein report a case in which stereotactic body radiotherapy (SBRT) was performed on target lesions detected by DWIBS and successfully suppressed disease progression.

Injection of hydrogel spacer increased maximal intrafractional prostate motion in anterior and superior directions during volumetric modulated arc therapy-stereotactic body radiation therapy for prostate cancer

Background

The aim of this study was to clarify the association between intrafractional prostate shift and hydrogel spacer.

Methods

Thirty-eight patients who received definitive volumetric modulated arc therapy (VMAT)-stereotactic body radiation therapy (SBRT) for prostate cancer with prostate motion monitoring in our institution in 2018–2019 were retrospectively evaluated. In order to move the rectum away from the prostate, hydrogel spacer (SpaceOAR system, Boston Scientific, Marlborough, the United States) injection was proposed to the patients as an option in case of meeting the indication of use. We monitored intrafractional prostate motion by using a 4-dimensional (4D) transperineal ultrasound device: the Clarity 4D ultrasound system (Elekta AB). The deviation of the prostate was monitored in each direction: superior-inferior, left–right, and anterior–posterior. We also calculated the vector length. The maximum intrafractional displacement (MID) per fraction for each direction was detected and mean of MIDs was calculated per patient. The MIDs in the non-spacer group and the spacer group were compared using the unpaired t-test.

Results

We reviewed 33 fractions in eight patients as the spacer group and 148 fractions in 30 patients as the non-spacer group. The superior MID was 0.47 ± 0.07 (mean ± SE) mm versus 0.97 ± 0.24 mm (P = 0.014), the inferior MID was 1.07 ± 0.11 mm versus 1.03 ± 0.25 mm (P = 0.88), the left MID was 0.74 ± 0.08 mm versus 0.87 ± 0.27 mm (P = 0.55), the right MID was 0.67 ± 0.08 mm versus 0.92 ± 0.21 mm (P = 0.17), the anterior MID was 0.45 ± 0.06 mm versus 1.16 ± 0.35 mm (P = 0.0023), and the posterior MID was 1.57 ± 0.17 mm versus 1.37 ± 0.22 mm (P = 0.56) in the non-spacer group and the spacer group, respectively. The max of VL was 2.24 ± 0.19 mm versus 2.89 ± 0.62 mm (P = 0.19), respectively.

Conclusions

Our findings suggest that maximum intrafractional prostate motion during VMAT-SBRT was larger in patients with hydrogel spacer injection in the superior and anterior directions. Since this difference seemed not to disturb the dosimetric advantage of the hydrogel spacer, we do not recommend routine avoidance of the hydrogel spacer use.

The Efficacy of Hemostatic Radiotherapy for Advanced Malignancies Assessed by World Health Organization Bleeding Status

Purpose 

This retrospective study aimed to evaluate the efficacy of radiotherapy for the palliation of bleeding symptoms of advanced malignancies.

Patients and methods

We included 36 consecutive patients treated for hemostatic intent by radiotherapy at our institution, from August 2013 to January 2019. Patient bleeding status was assessed according to the World Health Organization (WHO) bleeding status before and after radiotherapy.

Results

We identified 36 consecutive patients, consisting of 14 men and 22 women. The median follow-up period after radiotherapy for all cases was 2.5 months (range: 0.4-37.7 months), and the one-year OS was 47.1% (95% confidence interval: 23.5%-67.6%). Of the 36 patients, 29 (81%) showed improvement by one point or more in the WHO bleeding status. A total of 15 patients received 30 Gy in 10 fractions with a biologically effective dose (BED10) of 39 Gy (high BED arm). The remaining 21 patients had received radiotherapy with a BED10 of less than 39 (low BED arm, range of BED10: 11.2-30 Gy). In the high BED arm, 14 of the 15 patients (91%) showed improvement on the WHO bleeding status. In the low BED arm, 15 of the 21 patients (71%) showed improvement on the WHO bleeding status. There was no statistically significant difference in the improvement rate between the high and low BED arms (p = 0.200).

Conclusion

There is no universal standard to evaluate the hemostatic effect of palliative radiotherapy. In this retrospective study, we investigated the clinical outcomes of hemostatic irradiation as assessed by WHO bleeding status.