Comparing different boost concepts and beam configurations for proton therapy of pancreatic cancer.

Background and Purpose: Interfractional geometrical and anatomical variations impact the accuracy of proton therapy for pancreatic cancer. This study investigated field-in-field (FIF) and simultaneous integrated boost (SIB) concepts for scanned proton therapy treatment with different beam configurations. Materials and Methods: Robustly optimized treatment plans for fifteen patients were generated using FIF and SIB techniques with two, three, and four beams. The prescribed dose in 20 fractions was 60 Gy(RBE) for the internal gross tumor volume (IGTV) and 46 Gy(RBE) for the internal clinical target volume. Verification computed tomography (vCT) scans was performed on treatment days 1, 7, and 16. Initial treatment plans were recalculated on the rigidly registered vCTs. V100% and D95% for targets and D2cm3 for the stomach and duodenum were evaluated. Robustness evaluations (range uncertainty of 3.5 %) were performed to evaluate the stomach and duodenum dose-volume parameters. Results: For all techniques, IGTV V100% and D95% decreased significantly when recalculating the dose on vCTs (p < 0.001). The median IGTV V100% and D95% over all vCTs ranged from 74.2 % to 90.2 % and 58.8 Gy(RBE) to 59.4 Gy(RBE), respectively. The FIF with two and three beams, and SIB with two beams maintained the highest IGTV V100% and D95%. In robustness evaluations, the ΔD2cm3 of stomach was highest in two beams plans, while the ΔD2cm3 of duodenum was highest in four beams plans, for both concepts. Conclusion: Target coverage decreased when recalculating on CTs at different time for both concepts. The FIF with three beams maintained the highest IGTV coverage while sparing normal organs the most.

Simultaneous boost radiotherapy versus conventional dose radiotherapy for patients with newly diagnosed glioblastoma: a multi-institutional analysis.

We compared survival outcomes of high-dose concomitant boost radiotherapy (HDCBRT) and conventional dose radiotherapy (CRT) for newly diagnosed glioblastoma (GB). Patients treated with intensity-modulated radiation therapy for newly diagnosed GB were included. In HDCBRT, specific targets received 69, 60, and 51 Gy in 30 fractions, while 60 Gy in 30 fractions was administered with a standard radiotherapy method in CRT. Overall survival (OS) and progression-free survival (PFS) were compared using the Log-rank test, followed by multivariate Cox analysis. The inverse probability of treatment weighting (IPTW) method was also applied to each analysis. Among 102 eligible patients, 45 received HDCBRT and 57 received CRT. With a median follow-up of 16 months, the median survival times of OS and PFS were 21 and 9 months, respectively. No significant differences were observed in OS or PFS in the Kaplan-Meier analyses. In the multivariate analysis, HDCBRT correlated with improved OS (hazard ratio, 0.49; 95% confidence interval, 0.27-0.90; P = 0.021), and this result remained consistent after IPTW adjustments (P = 0.028). Conversely, dose suppression due to the proximity of normal tissues and IMRT field correlated with worse OS and PFS (P = 0.008 and 0.049, respectively). A prospective study with a stricter protocol is warranted to validate the efficacy of HDCBRT for GB.

Late genitourinary toxicity in salvage radiotherapy for prostate cancer after radical prostatectomy: impact of daily fraction doses.

OBJECTIVE: To evaluate the impact of daily fraction doses on late genitourinary (GU) toxicity after salvage radiotherapy (SRT) for prostate cancer. METHODS: This multi-institutional retrospective study included 212 patients who underwent SRT between 2008 and 2018. All patients received image-guided intensity-modulated SRT at a median dose of 67.2 Gy in 1.8-2.3 Gy/fraction. The cumulative rates of late grade ≥2 GU and gastrointestinal (GI) toxicities were compared using Gray test, stratified by the ≤2.0 Gy/fraction (n = 137) and ≥2.1 Gy/fraction groups (n = 75), followed by multivariate analyses. The total dose was represented as an equivalent dose in 2-Gy fractions (EQD2) with α/ß = 3 Gy. RESULTS: After a median follow-up of 63 months, the cumulative rates of 5-year late grade ≥2 GU and GI toxicities were 14% and 2.5%, respectively. The cumulative rates of 5-year late grade ≥2 GU toxicity in the ≥2.1 Gy/fraction and ≤2.0 Gy/fraction groups were 22% and 10%, respectively (P = .020). In the multivariate analysis, ≥2.1 Gy/fraction was still associated with an increased risk of late grade ≥2 GU toxicity (hazard ratio, 2.37; 95% confidence interval, 1.12-4.99; P = .023), while the total dose was not significant. CONCLUSION: The present results showed that ≥2.1 Gy/fraction resulted in a higher incidence of late grade ≥2 GU toxicity in SRT. ADVANCES IN KNOWLEDGE: The impact of fraction doses on late GU toxicity after SRT remains unknown. The results suggest that higher fraction doses may increase the risk of late GU toxicity in SRT.

Impact of radiation doses on clinical relapse of biochemically recurrent prostate cancer after prostatectomy.

The relationship between radiation doses and clinical relapse in patients receiving salvage radiotherapy (SRT) for biochemical recurrence (BCR) after radical prostatectomy (RP) remains unclear. We identified 292 eligible patients treated with SRT between 2005 and 2018 at 15 institutions. Clinical relapse-free survival (cRFS) between the ≥ 66 Gy (n = 226) and < 66 Gy groups (n = 66) were compared using the Log-rank test, followed by univariate and multivariate analyses and a subgroup analysis. After a median follow-up of 73 months, 6-year biochemical relapse-free survival, cRFS, cancer-specific survival, and overall survival rates were 58, 92, 98, and 94%, respectively. Six-year cRFS rates in the ≥ 66 Gy and < 66 Gy groups were 94 and 87%, respectively (p = 0.022). The multivariate analysis revealed that Gleason score ≥ 8, seminal vesicle involvement, PSA at BCR after RP ≥ 0.5 ng/ml, and a dose < 66 Gy correlated with clinical relapse (p = 0.015, 0.012, 0.024, and 0.0018, respectively). The subgroup analysis showed the consistent benefit of a dose ≥ 66 Gy in patients across most subgroups. Doses ≥ 66 Gy were found to significantly, albeit borderline, increase the risk of late grade ≥ 2 GU toxicity compared to doses < 66 Gy (14% vs. 3.2%, p = 0.055). This large multi-institutional retrospective study demonstrated that a higher SRT dose (≥ 66 Gy) resulted in superior cRFS.

[Case of Long-Term Response to Radiotherapy for Intramedullary Spinal Cord Metastasis from Ovarian Cancer after Surgery].

Intramedullary spinal cord metastasis(ISCM)often causes spinal cord neuropathy and should be treated as an oncologic emergency. However, it recurs in most cases after treatment, ISCM is a disease with a very unfavorable prognosis. Herein, we report a successfully treated case of ISCM with emergent and high-dose radiotherapy. A 53-year-old woman had difficulty walking without assistance 2 years after surgery for ovarian cancer. She received emergent radiotherapy at a total dose of 50 Gy in 25 fractions. Her neurological symptoms dramatically improved over 3 weeks after radiotherapy. ISCM has been controlled using the imaging tests at 5 years after radiotherapy. We believe that both emergent and high-dose radiotherapy were effective for ISCM.

Symptomatic radiation-induced rib fractures after stereotactic body radiotherapy for early-stage non-small cell lung cancer.

Background and purpose: The present study investigated the relationships between the risk of radiation-induced rib fractures (RIRF) and clinical and dosimetric factors in stereotactic body radiotherapy (SBRT) for early-stage non-small cell lung cancer (NSCLC). We also examined dosimetric parameters associated with symptomatic or asymptomatic RIRF and the dosimetric threshold for symptomatic RIRF. Materials and methods: We reviewed 244 cases of early-stage NSCLC treated with SBRT. Gray's test and the Fine-Gray model were performed to examine the relationships between clinical and dosimetric factors and grade ≥ 2 (i.e., symptomatic) RIRF. The effects of each dose parameter on grade ≥ 1 and ≥ 2 RIRF were assessed with the Fine-Gray model. The t-test was used to compare each dose parameter between the grade 1 and grade ≥ 2 groups. Optimal thresholds were tested using receiver operating characteristic (ROC) curves. Results: With a median follow-up period of 48 months, the 4-year cumulative incidence of grade ≥ 1 and grade ≥ 2 RIRF were 26.4 % and 8.0 %, respectively. Regarding clinical factors, only age was associated with the development of grade ≥ 2 RIRF (p = 0.024). Among dosimetric parameters, only V40Gy significantly differed between the grade 1 and grade ≥ 2 groups (p = 0.015). The ROC curve analysis of grade ≥ 2 RIRF showed that the optimal diagnostic thresholds for D3cc, D4cc, D5cc, and V40Gy were 45.86 Gy (area under the curve [AUC], 0.706), 39.02 Gy (AUC, 0.705), 41.62 Gy (AUC, 0.702), and 3.83 cc (AUC, 0.730), respectively. These results showed that V40Gy ≤ 3.83 cc was the best indicator of grade ≥ 2 RIRF. The 4-year incidence of grade ≥ 2 RIRF in the V40Gy ≤ 3.83 cc vs. > 3.83 cc groups was 1.8 % vs. 14.2 % (p = 0.001). Conclusion: The present results recommend V40Gy ≤ 3.83 cc as the threshold for grade ≥ 2 RIRF in SBRT.

Dosimetric and radiobiological analyses of a de-escalation strategy for elective nodal regions in human papillomavirus-associated oropharyngeal cancer.

Introduction: In this simulation study, we examined the effects of a de-escalation strategy with a reduced dose to subclinical nodal regions in patients with human papillomavirus (HPV)-associated oropharyngeal carcinoma (OPC). Methods: We created two patterns of intensity-modulated radiotherapy for 16 patients with HPV-associated OPC. In the standard and de-escalation plans, the initial field including elective nodal regions received 46 and 30 Gy, followed by 20 and 36 Gy to the cutdown field, respectively. Comparison metrics were set for each organ at risk (OAR). We compared these metric values and the probability of adverse effects based on the normal tissue complication probability (NTCP) model between the two plans. Results: Both plans generally met the dose constraints for the targets and all OAR. Among the comparison metrics, the mean doses to the brain, pharyngeal constrictor muscle, thyroid, and skin and the dose to a 1 % volume of the skin were higher in the standard plan than in the de-escalation plan (P = 0.031, 0.007, < 0.001, < 0.001, and 0.006, respectively). NTCP analyses revealed that the probability of adverse effects in the ipsilateral parotid gland and thyroid was higher in the standard plan than in the de-escalation plan (standard vs. de-escalation plans: ipsilateral parotid gland, 6.4 % vs. 5.0 %, P = 0.016; thyroid, 3.3 % vs. 0.5 %, P < 0.001). Conclusions: A de-escalation strategy with elective nodal regions is a promising treatment to prevent a decline in the quality of life in patients with HPV-associated OPC, particularly xerostomia, dysphagia, and hypothyroidism.

Clinical Outcomes of Radiation Therapy for Choroidal Metastases and A Literature Review.

INTRODUCTION: Radiation therapy (RT) for choroidal metastasis (CM) aims to preserve vision and achieve local control (LC), thereby maintaining quality of life. The present study reports the clinical outcomes of RT for CM and reviews the literature. METHODS: We retrospectively collected data on 11 patients with CM; their primary tumors were breast cancer (n=3), lung cancer (n=3), leukemia (n=2), lymphoma (n=2), and gastric cancer (n=1). Four patients had bilateral CM. The median radiation dose was 39 Gy in 13 fractions (range, 20-50 Gy in 10-25 fractions). We investigated changes in visual acuity, tumor responses, morbidities, LC, and overall survival (OS). A systematic review of literature published between 1990 and 2020 was performed using the PubMed database. RESULTS: One, 1, and 6 patients had improved, stabilized, and worse visual acuity, respectively (data missing for 3 patients). Nevertheless, eight patients considered their visual acuity to have improved or remained the same after RT. Among 15 lesions in 11 patients, complete and partial responses were observed in 2 and 6, respectively (data missing for 7 lesions in 4 patients). Three-year LC and OS rates were 100 and 32%, respectively. Grade ≥ 3 morbidities were not observed. In the literature review, the most common primary cancer was breast cancer followed by lung cancer. Improvements in or the stabilization of visual acuity was observed in 80% of patients (range, 47-100), and the median survival time was 11 months (range, 4.9-23). CONCLUSION: RT is an efficient and safe palliative treatment for CM without severe toxicity.

Importance of the Number and Location of Lymph Node Metastasis in Oropharyngeal Cancer.

BACKGROUND/AIM: The 8th edition of the American Joint Committee on Cancer staging system classifies oropharyngeal cancer (OPC) by the expression of p16. The discrepancy observed in this system between pathological and clinical N-stages in p16-positive OPC has provoked controversy. Therefore, this study investigated prognostic factors not included in the new staging system for p16-positive OPC patients. PATIENTS AND METHODS: Patients with non-metastatic OPC receiving radiotherapy were reviewed. Clinical lymph node statuses were reassessed based on contrast-enhanced computed tomography and fluorodeoxyglucose positron emission tomography. Overall survival (OS) and cause-specific survival (CSS) were analyzed using multivariate analyses to adjust baseline imbalances. RESULTS: In total, 166 OPC patients were reviewed. Among them, 81 patients with p16-positive were analyzed. Three or more lymph node metastases (LNM) were observed in 21 p16-positive OPCs. Retropharyngeal lymph node metastasis (Rp) was found in 12. Three-year OS, CSS, and progression-free survival rates in p16-positive patients were 76, 88, and 81%, respectively. In multivariate analyses of p16-positive OPC, LNM ≥3 was a prognostic factor of OS (hazard ratio=9.30, p<0.001) and CSS (hazard ratio=17.80, p=0.005). Rp was associated with poor CSS (hazard ratio=8.73, p=0.03). In N0-1 p16-positive patients, LNM ≥3 trended to be associated with poor OS (hazard ratio=3.93, p=0.06). CSS in patients with Rp was unfavorable (hazard ratio=70.16, p=0.05). CONCLUSION: LNM ≥3 and Rp may be predictive of OS and CCS in p16-positive OPC. These are also possibly used to subcategorize p16-positive cN0-1 OPC. Further validation of lymph node staging is needed to refine the clinical staging system.

Clinical Outcomes of Radiation Therapy for Angiosarcoma of the Scalp and Face: A Multi-Institutional Observational Study.

Angiosarcoma of the scalp and face (ASF) is a rare, aggressive tumor often treated with multimodal therapy, including radiation therapy (RT). This study assessed RT outcomes for ASF and identified prognostic factors. Data from 68 non-metastatic ASF patients undergoing RT with or without other therapies were analyzed. Median radiation dose was 66 Gy in 33 fractions (interquartile range (IQR) 60-70 Gy in 28-35 fractions). Local control (LC), progression-free survival (PFS), and overall survival (OS) rates were calculated using Kaplan-Meier analysis. Multivariate analyses and adverse event evaluation were conducted. Median patient age was 75 years (IQR 71-80 years), with a median follow-up of 17 months (IQR 11-42 months). One-/three-year LC rates were 57/37%, PFS rates were 44/22%, and OS rates were 81/44%. Multivariate analyses showed that an equivalent dose in a 2 Gy fraction (EQD2) >66 Gy correlated with improved LC (HR 2.35, 95% CI 1.03-5.32, p = 0.041). Combining chemotherapy (HR 2.43, 95% CI 1.08-5.46, p = 0.032) or surgery (HR 2.41, 95% CI 1.03-5.59, p = 0.041) improved PFS. No factors influenced OS. Late grade 3+ toxicities occurred in 1%, with one patient developing a grade 4 skin ulcer. These findings suggest that EQD2 > 66 Gy and combining chemotherapy or surgery can enhance LC or PFS in ASF. Further prospective studies are needed to determine the optimal treatment strategy for this rare malignancy, particularly in elderly patients.

Intensity-modulated radiation therapy with the central shielding technique for patients with uterine cervical cancer†.

We aimed to examine outcomes and toxicities of intensity-modulated radiation therapy (IMRT) with the central shielding (CS) technique for patients with uterine cervical cancer. This retrospective study included 54 patients with International Federation of Gynecology and Obstetrics IB-IVA cancer. Whole pelvic radiotherapy or extended-field radiotherapy were performed at the dose of 50.4 Gy in 28 fractions with helical tomotherapy (HT). Six patients had para-aortic lymph node metastases. The CS technique with HT was utilized after a total dose of 28.8-41.4 Gy to reduce doses to the rectum and bladder. The prescribed dose of intracavitary brachytherapy was mainly 18-24 Gy in three or four fractions at point A. Concurrent chemotherapy was used for 47 patients (87%). Median follow-up time was 56 months. Seventeen patients (31%) developed recurrence. The recurrence of the cervix was observed in two patients (4%). The 5-year rates of the locoregional control, progression-free survival (PFS) and overall survival were 79, 66 and 82%, respectively. Among several factors evaluated, histological type of adenocarcinoma was only a significantly worse prognostic factor for PFS by multivariate analysis (hazard ratio, 4.9 [95% confidence interval, 1.3-18], P = 0.018). Grade 2 or higher late toxicities were observed in nine patients (17%). Two patients (4%) each had grade 3 proctitis and grade 3 ileus, respectively. No grade 4 toxicity or treatment-related death was observed. The results suggest that IMRT with the CS technique allows a high local control without increasing the risk of complications for cervical cancer patients.

Clinical and dosimetric factors for symptomatic radiation pneumonitis after stereotactic body radiotherapy for early-stage non-small cell lung cancer.

Background and purpose: The present study attempted to identify risk factors for symptomatic radiation pneumonitis (RP) after stereotactic body radiotherapy (SBRT) in patients with early-stage non-small cell lung cancer (NSCLC). Materials and methods: We reviewed 244 patients with early-stage NSCLC treated with SBRT. The primary endpoint was the incidence of grade ≥2 RP. Gray's test was performed to examine the relationship between clinical risk factors and grade ≥2 RP, and the Fine-Gray model was used for a multivariate analysis. The effects of each dose parameter on grade ≥2 RP were evaluated with the Fine-Gray model and optimal thresholds were tested using receiver operating characteristic (ROC) curves. Results: With a median follow-up period of 48 months, the 4-year cumulative incidence of grade ≥2 RP was 15.3%. Gray's test revealed that tumor size, a central tumor, interstitial pneumonia, and the biologically effective dose correlated with RP. In the multivariate analysis, a central tumor and interstitial pneumonia remained significant factors (p < 0.001, p = 0.002). Among dose parameters, the total lung volume (%) receiving at least 8 Gy (V8), V10, V20, and the mean lung dose correlated with RP (p = 0.012, 0.011, 0.022, and 0.014, respectively). The results of the Fine-Gray model and ROC curve analyses showed that V10 >16.7% was the best indicator of symptomatic RP among dose parameters. Conclusion: The present results suggest that a central tumor and interstitial pneumonia are independent risk factors for symptomatic RP and lung V10 ≤16.7% is recommended as the threshold in SBRT.

Comparison of Recurrence Patterns between Adenocarcinoma and Squamous Cell Carcinoma after Stereotactic Body Radiotherapy for Early-Stage Lung Cancer.

We compared recurrence patterns between adenocarcinoma (ADC) and squamous cell carcinoma (SCC) after stereotactic body radiotherapy (SBRT) for early-stage lung cancer. Patients with ADC and SCC histology, who were treated with SBRT for clinical stage IA1-IIA lung cancer at our institution, were included in the analysis. The rates of disease-free survival (DFS), overall survival (OS), local recurrence (LR), lymph node metastasis (LNM), and distant metastasis (DM) were calculated using the Kaplan-Meier method or the cumulative incidence function. Among the 204 patients analyzed, 138 and 66 were in the ADC and SCC groups, respectively. The median follow-up period was 60 months. The five-year DFS and OS rates were 57% vs. 41% and 69% vs. 48% in the ADC and SCC groups, respectively (p = 0.015 and 0.019, respectively). In the multivariate analysis, the histological type was not associated with DFS or OS. Five-year LR, LNM, and DM rates were 10% vs. 24%, 12% vs. 20%, and 25% vs. 27% in the ADC and SCC groups, respectively (p = 0.0067, 0.074, and 0.67, respectively). The multivariate analysis identified the histological type of SCC as an independent factor for LR (hazard ratio, 2.41; 95% confidence interval, 1.21-4.77; p = 0.012). The present results suggest that the risk of LR after SBRT is higher for SCC than for ADC.

Acute genitourinary toxicity of pencil beam scanning proton therapy for localized prostate cancer: utility of the transition zone index and average urinary flow rate in predicting acute urinary retention.

BACKGROUND: The purpose of this study was to evaluate the incidence of acute genitourinary toxicities in patients undergoing pencil beam scanning proton therapy for prostate cancer and investigate predictive factors associated with acute urinary retention. METHODS: A total of 227 patients treated between 2018 and 2021 were divided into the normo-fractionated proton therapy group (n = 107) and the moderately hypo-fractionated proton therapy group (n = 120), with prescribed doses of 76-78 Gy relative biological effectiveness in 38-39 fractions and 60-63 Gy relative biological effectiveness in 20-21 fractions, respectively. Uroflowmetry parameters and the transition zone index were prospectively evaluated. RESULTS: Forty-five patients (42%) in the normo-fractionated proton therapy and 33 (28%) in the moderately hypo-fractionated proton therapy developed acute grade 2 genitourinary toxicities (P = 0.02). The most common acute genitourinary toxicity was acute urinary retention. Thirty-nine patients (36%) treated with normo-fractionated proton therapy and 27 (23%) treated with moderately hypo-fractionated proton therapy developed grade 2 acute urinary retention (P = 0.02). No patients developed grade ≥ 3 toxicity. Univariate analysis showed the transition zone index, prostate volume, international prostate symptom score, voided volume, maximum flow rate and average flow rate were associated with grade 2 acute urinary retention. Multivariate analysis in both groups revealed the transition zone index (P = 0.025 and 0.029) and average flow rate (P = 0.039 and 0.044) were predictors of grade 2 acute urinary retention. CONCLUSIONS: The incidence of acute genitourinary toxicities was lower in the moderately hypo-fractionated proton therapy compared with the normo-fractionated proton therapy. Lower pretreatment average flow rate and a higher transition zone index were useful predictors of grade 2 acute urinary retention.

Radiotherapy for ductal carcinoma of the prostate: an analysis based on the Japanese radiation oncology study group survey.

BACKGROUND: The clinical characteristics of prostate ductal carcinoma is still unclear, and treatment strategy has not yet been established due to its rarity. Therefore, we conducted a multicenter survey of radiation therapy for prostate ductal carcinoma in Japan. METHOD: Data of patients with ductal carcinoma of the prostate treated with radiation therapy between 1996 and 2018 were extracted from the database of each facility. RESULTS: Fifty-two treatment records of 41 patients were collected from nine institutions. The treatment purpose and situations were varied curative intent to palliation. Twenty-eight patients received curative treatments. The median follow-up period of these patients was 68 months. Androgen deprivation therapy was combined with radiation therapy in 26 cases (93%). X-ray and particle irradiation was used. Radiation dose range was 63-78 Gy; 5-year overall survival, progression-free survival and biochemical relapse-free survival were 87.0, 79.3 and 79.3%, respectively. One patient experienced Grade 3 radiation proctitis and one experienced Grade 3 radiation cystitis. There were no Grade 4 or worse adverse events. CONCLUSION: Most patient received similar treatment with adenocarcinoma of prostate, and the clinical results were compatible. For more reliable evidence, further studies are required.

Daily irradiation versus irradiation at two- to three-day intervals in stereotactic radiotherapy for patients with 1-5 brain metastases: study protocol for a multicenter open-label randomized phase II trial.

BACKGROUND: Radiobiological daily changes within tumors are considered to be quite different between stereotactic radiotherapy (SRT) (e.g., 50 Gy in 4 fractions) and conventional radiotherapy (e.g., 60 Gy in 30 fractions). We aim to assess the optimal interval of irradiation in SRT and compare outcomes of daily irradiation with irradiation at two- to three-day intervals in SRT for patients with one to five brain metastases (BM). METHODS: This study is conducted as a multicenter open-label randomized phase II trial. Patients aged 20 or older with one to five BM, less than 3.0 cm diameter, and Karnofsky Performance Status ≥70 are eligible. A total of 70 eligible patients will be enrolled. After stratifying by the number of BMs (1, 2 vs. 3-5) and diameter of the largest tumor (< 2 cm vs. ≥ 2 cm), we randomly assigned patients (1:1) to receive daily irradiation (Arm 1), or irradiation at two- to three-day intervals (Arm 2). Both arms are performed with total dose of 27-30 Gy in 3 fractions. The primary endpoint is an intracranial local control rate, defined as intracranial local control at initially treated sites. We use a randomized phase II screening design with a two-sided α of 0∙20. The phase II trial is positive with p < 0.20. All analyses are intention to treat. This study is registered with the UMIN-clinical trials registry, number UMIN000048728. DISCUSSION: This study will provide an assessment of the impact of SRT interval on local control, survival, and toxicity for patients with 1-5 BM. The trial is ongoing and is recruiting now. TRIAL REGISTRATION: UMIN000048728. Date of registration: August 23, 2022. https://center6.umin.ac.jp/cgi-bin/ctr/ctr_view_reg.cgi?recptno=R000055515 .

International consensus on radiotherapy in metastatic non-small cell lung cancer.

Background: Lung cancer is the leading cause of cancer-related death worldwide, with non-small cell lung cancer (NSCLC) accounting for most cases. While radiotherapy has historically served as a palliative modality in metastatic NSCLC, considerable advances in its technology and the continuous development of cutting-edge therapeutic agents, such as targeted therapy and immune checkpoint inhibitors (ICIs), are increasing its role in the multi-disciplinary management of the disease. Methods: International radiotherapy experts were convened to consider and reach consensuses on the clinical utilities of radiotherapy in metastatic NSCLC, with the aim to provide patient-focused, up to date, evidence-based, recommendations to assist cancer specialists in the management of patients with metastatic NSCLC worldwide. Results: Timely radiotherapy can offer rapid symptom alleviation and allow subsequent aggressive treatment approaches in patients with heavy tumor burden and/or oncologic emergencies. In addition, appropriate incorporation of radiotherapy as concurrent, consolidation, or salvage therapy makes it possible to achieve long-term survival, or even cure, for patients with oligo-metastatic disease. Cranial radiotherapy plays an important role in the management of brain metastasis, potentially augmenting the response and prolonging survival associated with targeted agents and ICIs. However, key questions remain, such as the appropriate choice of radiation techniques, optimal sequence of systemic therapies and radiotherapy, and optimal patient selection for such combination strategies. Although a strong rationale for combining radiotherapy and ICIs exists, its optimal parameters in this setting remain to be established. Conclusions: In the modern era, radiotherapy serves not only as a palliative tool in metastatic NSCLC, but also plays active roles in patients with oligo-focal disease, CNS metastasis and receiving ICIs.

Comparison of intensity-modulated radiotherapy with the 5-field technique, helical tomotherapy and volumetric modulated arc therapy for localized prostate cancer.

The outcomes of three methods of intensity-modulated radiation therapy (IMRT) for localized prostate cancer were evaluated. Between 2010 and 2018, 308 D'Amico intermediate- or high-risk patients were treated with 2.2 Gy daily fractions to a total dose of 74.8 Gy in combination with hormonal therapy. Overall, 165 patients were treated with 5-field IMRT using a sliding window technique, 66 were then treated with helical tomotherapy and 77 were treated with volumetric modulated arc therapy (VMAT). The median age of patients was 71 years. The median follow-up period was 75 months. Five-year overall survival (OS) and biochemical or clinical failure-free survival (FFS) rates were 95.5 and 91.6% in the 5-field IMRT group, 95.1 and 90.3% in the tomotherapy group and 93.0 and 88.6% in the VMAT group, respectively, with no significant differences among the three groups. The 5-year cumulative incidence of late grade ≥2 genitourinary and gastrointestinal toxicities were 7.3 and 6.2%, respectively, for all patients. Late grade ≥2 gastrointestinal toxicities were less frequent in patients undergoing VMAT (0%) than in patients undergoing 5-field IMRT (7.3%) and those undergoing tomotherapy (11%) (P = 0.025), and this finding appeared to be correlated with the better rectal DVH parameters in patients undergoing VMAT. Other toxicities did not differ significantly among the three groups, although bladder dose-volume parameters were slightly worse in the tomotherapy group than in the other groups. Despite differences in the IMRT delivery methods, X-ray energies and daily registration methods, all modalities may be used as IMRT for localized prostate cancer.

Role of stereotactic body radiotherapy for early-stage non-small-cell lung cancer in patients borderline for surgery due to impaired pulmonary function.

AIM: Stereotactic body radiotherapy (SBRT) is recommended only for inoperable patients with early-stage (e-stage) non-small-cell lung cancer (NSCLC). We compared outcomes between surgery and SBRT in patients borderline for surgery due to impaired pulmonary function (PF). METHODS: We reviewed single-institution retrospective data of 578 patients with clinically T1-2N0M0 NSCLC treated by surgery or SBRT between 2004 and 2014, and extracted a cohort with borderline impaired PF for surgery, which was defined as predicted postoperative (PPO) forced expiratory volume in 1 s (FEV1 ) of <50% and ≥30%. Overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS) were compared between surgery and SBRT using propensity score-matching (PSM) to avoid bias. RESULTS: Among a total of 116 eligible patients with a median PPO FEV1 of 45%, PSM identified 25 patients from each group with similar characteristics. The median age, pretreatment FEV1 , and follow-up durations for the surgery and SBRT groups were 75 and 74 years, 58% and 56%, and 56 and 60 months, respectively. The 5-year OS, CSS, and DFS rates of the surgery versus SBRT groups were 60% versus 63%, 76% versus 81%, and 52% versus 48%, respectively (p = 0.97, 0.81, and 0.99). The surgical mortality was 4.0%, but no treatment-related death was observed after SBRT. The incidence of ≥ grade 2 adverse events after surgery was double that after SBRT (40% versus 20%, p = .22). CONCLUSION: Our study suggests that SBRT is a reasonable option for patients with e-stage NSCLC and impaired PF who are considered borderline candidates for surgery.

Dosimetric Comparison of Helical Tomotherapy and Intensity-Modulated Proton Therapy in Hippocampus- and Scalp-Sparing Whole Brain Radiotherapy.

Objective: Cognitive decline and alopecia after radiotherapy are challenging problems. We aimed to compare whole brain radiotherapy (WBRT) plans reducing radiation dose to the hippocampus and scalp between helical tomotherapy (HT) and intensity-modulated proton therapy (IMPT). Methods: We conducted a planning study of WBRT for 10 patients. The clinical target volume was defined as the whole brain excluding the hippocampus avoidance (HA) region. The prescribed dose was 30 Gy in 10 fractions to cover 95% of the target. Constraint goals were defined for the target and organs at risk (OAR). Results: Both techniques met the dose constraints for the target and OAR. However, the coverage of the target (dose covering 95% [D95%] and 98% [D98%] of the volume) were better in IMPT than HT (HT vs IMPT: D95%, 29.9 Gy vs 30.0 Gy, P < .001; D98%, 26.7 Gy vs 28.1 Gy, P = .002). The homogeneity and conformity of the target were also better in IMPT than HT (HT vs IMPT: homogeneity index, 1.50 vs 1.28, P < .001; conformity index, 1.30 vs 1.14, P < .001). IMPT reduced the D100% of the hippocampus by 59% (HT vs IMPT: 9.3 Gy vs 3.8 Gy, P < .001) and reduced the Dmean of the hippocampus by 37% (HT vs IMPT: 11.1 Gy vs 7.0 Gy, P < .001) compared with HT. The scalp IMPT reduced the percentage of the volume receiving at least 20 Gy (V20Gy) and V10Gy compared with HT (HT vs IMPT: V20Gy, 56.7% vs 6.6%, P < .001; V10Gy, 90.5% vs 37.1%, P < .001). Conclusion: Both techniques provided acceptable target dose coverage. Especially, IMPT achieved excellent hippocampus- and scalp-sparing. HA-WBRT using IMPT is a promising treatment to prevent cognitive decline and alopecia.