Acute adverse events of ultra-hypofractionated whole-breast irradiation after breast-conserving surgery for early breast cancer in Japan: an interim analysis of the multi-institutional phase II UPBEAT study

BACKGROUND

The applicability of ultra-hypofractionated (ultra-HF) whole-breast irradiation (WBI) remains unknown in Japanese women. This study aimed to evaluate the safety and efficacy of this approach among Japanese women and report the results of an interim analysis performed to assess acute adverse events (AEs) and determine whether it was safe to continue this study.

METHODS

We enrolled Japanese women with invasive breast cancer or ductal carcinoma in situ who had undergone breast-conserving surgery, were aged ≥ 40 years, had pathological stages of Tis-T3 N0-N1, and had negative surgical margins. Ultra-HF-WBI was delivered at 26 Gy in five fractions over one week. When the number of enrolled patients reached 28, patient registration was paused for three months. The endpoint of the interim analysis was the proportion of acute AEs of grade ≥ 2 (Common Terminology Criteria for Adverse Events v5.0) within three months.

RESULTS

Of the 28 patients enrolled from seven institutes, 26 received ultra-HF-WBI, and 2 were excluded due to postoperative infections. No AEs of grade ≥ 3 occurred. One patient (4%) experienced grade 2 radiation dermatitis, and 18 (69%) had grade 1 radiation dermatitis. The other acute grade 1 AEs experienced were skin hyperpigmentation (n = 10, 38%); breast pain (n = 4, 15%); superficial soft tissue fibrosis (n = 3, 12%); and fatigue (n = 1, 4%). No other acute AEs of grade ≥ 2 were detected.

CONCLUSIONS

Acute AEs following ultra-HF-WBI were within acceptable limits among Japanese women, indicating that the continuation of the study was appropriate.

Population-based asymmetric margins for moving targets in real-time tumor tracking

BACKGROUND

Both geometric and dosimetric components are commonly considered when determining the margin for planning target volume (PTV). As dose distribution is shaped by controlling beam aperture in peripheral dose prescription and dose-escalated simultaneously integrated boost techniques, adjusting the margin by incorporating the variable dosimetric component into the PTV margin is inappropriate; therefore, geometric components should be accurately estimated for margin calculations.

PURPOSE

We introduced an asymmetric margin-calculation theory using the guide to the expression of uncertainty in measurement (GUM) and intra-fractional motion. The margins in fiducial marker-based real-time tumor tracking (RTTT) for lung, liver, and pancreatic cancers were calculated and were then evaluated using Monte Carlo (MC) simulations.

METHODS

A total of 74 705, 73 235, and 164 968 sets of intra- and inter-fractional positional data were analyzed for 48 lung, 48 liver, and 25 pancreatic cancer patients, respectively, in RTTT clinical trials. The 2.5th and 97.5th percentiles of the positional error were considered representative values of each fraction of the disease site. The population-based statistics of the probability distributions of these representative positional errors (PD-RPEs) were calculated in six directions. A margin covering 95% of the population was calculated using the proposed formula. The content rate in which the clinical target volume (CTV) was included in the PTV was calculated through MC simulations using the PD-RPEs.

RESULTS

The margins required for RTTT were at most 6.2, 4.6, and 3.9 mm for lung, liver, and pancreatic cancer, respectively. MC simulations revealed that the median content rates using the proposed margins satisfied 95% for lung and liver cancers and 93% for pancreatic cancer, closer to the expected rates than the margins according to van Herk's formula.

CONCLUSIONS

Our proposed formula based on the GUM and motion probability distributions (MPD) accurately calculated the practical margin size for fiducial marker-based RTTT. This was verified through MC simulations.

Correlation Between Dosimetric Parameters and Local Control in Definitive Radiotherapy for Head and Neck Cancers

BACKGROUND/AIM

Radiotherapy (RT) outcomes are generally reported based on stage, patient background, and concomitant chemotherapy. This study aimed to investigate the effects of the prescribed dose to gross tumor volume (GTV) and the calculation algorithm on local control in definitive RT for head and neck (H&N) cancers using follow-up images after RT.

PATIENTS AND METHODS

This study included 154 patients with H&N cancers treated by Volumetric Modulated Arc Therapy at the Kobe City Medical Center General Hospital. Patients were classified into those receiving definitive RT (70 Gy of irradiation) and those not receiving it. Follow-up images were used to categorize the patients into the responders and non-responders groups. In the non-responders group, follow-up images were imported into the treatment planning system, and the contours of the residual or recurrent areas (local failure) were extracted and fused with computed tomography-simulated images for treatment planning. Dose evaluation parameters included maximum dose, dose administered to 1% of the volume, dose administered to 50% of the volume, dose administered to 99% of the volume (D99%), and minimum dose (Dmin) administered to the GTV. The doses to the GTV were compared between responders and non-responders.

RESULTS

D99% exhibited significant differences between local failure and responders and between local failure and non-responders. Dmin showed significant differences between responders and non-responders and between responders and local failure.

CONCLUSION

This study emphasizes the importance of verifying dose distribution in all slices of treatment planning, highlighting the need for precise assessment of the dose to the GTV in head and neck cancers.

Clinical outcomes of scalp or face angiosarcoma treatment with intensity-modulated radiotherapy: a multicenter study

Combined modality therapy, including radiotherapy (RT), is a common treatment for scalp or face angiosarcoma. Although intensity-modulated radiotherapy (IMRT) can deliver homogeneous doses to the scalp or face, clinical data are limited. This multicenter study aimed to evaluate scalp or face angiosarcoma treated with definitive or post-operative IMRT. We retrospectively analyzed data from patients who received IMRT for scalp or face angiosarcoma at three institutions between January 2015 and March 2020. Local control (LC) rate, overall survival (OS), progression-free survival (PFS), recurrence patterns and toxicity were evaluated. Fifteen patients underwent IMRT during the study period. Definitive RT was performed on 10 patients and post-operative RT was performed on 5 patients. The 1-year LC rate was 85.7% (95% confidence interval [CI], 53.9-96.2%). The 1-year OS and PFS rates were 66.7% (95% CI, 37.5-84.6%) and 53.3% (95% CI, 26.3%-74.4%), respectively. Univariate analysis revealed that a clinical target volume over 500 cm3 was associated with poor LC. Distant metastasis was the most common recurrence pattern. All patients experienced Grade 2 or 3 radiation dermatitis, and five patients experienced grade ≥ 3 skin ulceration. One patient who underwent maintenance therapy with pazopanib developed Grade 5 skin ulceration. Fisher's exact test showed that post-operative RT was significantly associated with an increased risk of skin ulceration of grade ≥ 3. These results demonstrate that IMRT is a feasible and effective treatment for scalp or face angiosarcoma, although skin ulceration of grade ≥ 3 is a common adverse event in patients who receive post-operative RT.

Long-Term Results of a Multi-Institutional Study of Dynamic Tumor Tracking-Stereotactic Body Radiotherapy for Lung Tumors

PURPOSE/OBJECTIVE(S)

We had conducted a multi-institutional phase II study to evaluate the safety and efficacy of dynamic tumor tracking-stereotactic body radiotherapy (DTT-SBRT) for lung tumors. The primary endpoint was 2-year local control, which was reported to be 95.2%. After the initial evaluation of the primary endpoint, the study was extended as an observational study which was designed to evaluate 5-year survival and late toxicities. We present the long-term results of DTT-SBRT for lung tumors.

MATERIALS/METHODS

The main eligibility criteria for the study were as follows: (1) primary or metastatic lung cancer with a diameter of 5 cm or less, and up to 3 lesions without any extrapulmonary lesions; (2) ineligibility to standard surgery, or patient's refusal of surgery; (3) ECOG-PS of 0 to 2; and (4) expected range of respiratory motion of 10 mm or more. The study included 48 patients from four institutions with the median age of 80 years (range, 49-90 years). Forty-two patients had primary non-small-cell lung cancer, and 6 patients had metastatic lung tumors. Forty-eight tumors (median diameter, 23.5 mm; range, 5-47 mm) in 48 patients were targeted for DTT-SBRT using a gimbal-mounted linear accelerator. Prior to treatment planning, spherical gold markers were placed around the tumor to detect internal tumor motion using fluoroscopy. The prescribed dose was 50 Gy in four fractions. Treatment beams were delivered with DTT according to a 4D model that predicts internal tumor motion with abdominal wall motion. DTT-SBRT was successfully delivered to all but one patient who had poor correlation between abdominal wall and tumor motion.

RESULTS

Median follow-up period at data cutoff was 5.0 years (interquartile range, 3.1-6.3 years). Twenty-nine patients died; the causes of death were cancer-specific in 10 patients, comorbidity in 14 patients (pulmonary disease, renal failure, cerebral infarction, other malignancies, etc.), and unknown in 5 patients without cancer recurrence. Overall survival at 5 years was 51.5% (95% confidence interval [CI], 36.5-64.6%). Progression-free survival and local control at 5 years were 41.0% (95% CI, 27.0-54.5%) and 92.6% (95% CI, 78.7-97.6%), respectively. There were no grade 4-5 toxicities. One patient (2%) developed grade 3 radiation pneumonitis at 3 months. Grade 2 toxicities were observed in 9 patients (19%), including dyspnea, radiation pneumonitis, pleural effusion, rib fracture, and dermatitis.

CONCLUSION

Dynamic tumor tracking SBRT achieved the long-term efficacy with low incidence of severe toxicities in lung tumors with respiratory motion. In this elderly patient cohort, non-cancer deaths were observed more than cancer-specific deaths.

Major Cardiovascular Events after Chemoradiotherapy with or without Durvalumab in Patients with Stage III Non-Small Cell Lung Cancer: Supplementary Analysis

PURPOSE/OBJECTIVE(S)

RTOG 0617 showed that cardiac events are relatively common after high-dose thoracic radiotherapy. The aim of this study was to investigate the incidence and risk of major cardiovascular events (MACE) after concurrent chemoradiotherapy (CCRT) with or without durvalumab in patients with stage III non-small cell lung cancer (NSCLC) using the data from a multi-institutional study in Japan.

MATERIALS/METHODS

Patients who received CCRT for stage III NSCLC between July 2018 and July 2019 were enrolled in a multi-institutional study in Japan. MACE was defined as follows: symptomatic pericardial effusion, acute coronary syndrome, pericarditis, significant arrhythmia, and heart failure. The cumulative incidence of MACE, accounting for death as a competing risk, was calculated. Pre-existing coronary heart disease (CHD) included coronary artery disease, congestive heart failure, peripheral vascular disease, stroke, and extensive coronary artery calcification. The association between patient/treatment-related factors and MACE was assessed by multivariate analysis.

RESULTS

Among 178 patients with a median follow-up period of 42.5 months, 13 patients developed MACEs. The 3-year cumulative incidence of MACE was 6.9% (95% confidence interval [CI], 4.0-11.9%). Univariate analysis showed that female sex and mean heart dose (MHD) were marginally associated (3-year cumulative incidence, male 5.6% vs. female 12.1%; P = 0.12; MHD ≥ 6.3 Gy 4.8% vs. < 6.3 Gy 9.1%; P = 0.13), and pre-existing CHD was significantly associated with an increased risk of MACE (no CHD 4.3% vs. CHD 16.8%; P = 0.026). Consolidation durvalumab was not associated with an increased risk of MACE (no durvalumab 5.2% vs. durvalumab 7.4%; P = 0.89). Multivariate analysis showed that pre-existing CHD was significantly associated with MACE (hazard ratio, 4.22; 95% CI, 1.30-13.7; P = 0.016).

CONCLUSION

The incidence of MACE based on the real-world data in Japan was lower than previously reported. Pre-existing CHD was associated with an increased risk of MACE after CCRT in patients with stage III NSCLC, whereas the administration of consolidation durvalumab was not associated with an increased risk of MACE.

Real-World Study of Overall Survival in Patients with Stage III Non-Small Cell Lung Cancer Treated with Chemoradiotherapy with or without Durvalumab and an Exploratory Analysis of Effective Radiation Dose to the Immune Cells

PURPOSE/OBJECTIVE(S)

To investigate the real-world data on overall survival (OS) in patients with stage III non-small cell lung cancer (NSCLC) treated with concurrent chemoradiotherapy (CCRT) with or without consolidation durvalumab, and to perform an exploratory analysis on effective radiation dose to the immune cells (EDIC).

MATERIALS/METHODS

In our multi-institutional retrospective study, patients who received CCRT between July 2018 and July 2019 for stage III NSCLC in Japan were investigated. EDIC was estimated using mean lung dose, mean heart dose, body volume, body mean dose, and body weight, as reported in the secondary analysis of RTOG 0617. The cut-off value of EDIC was calculated using the maximally selected log-rank statistics.

RESULTS

One hundred and seventy-eight patients were eligible for the analysis (136 patients, CCRT with consolidation durvalumab [CCRT+D] cohort; 42 patients, CCRT cohort). The median follow-up period was 42.5 months. Three-year OS rates were 59.8% in the overall cohort: 60.5% in the CCRT+D cohort, and 58.0% in the CCRT cohort with no significant difference (hazard ratio [HR], 0.76; 95% confidence interval [CI], 0.45-1.27; P = 0.29). Univariate analysis showed that ECOG-PS, smoking history, histology, EGFR mutational status, gross tumor volume and EDIC were significantly associated with OS. Multivariate analysis showed that ECOG-PS 2, gross tumor volume ≥ 57 cm3 and EDIC ≥ 4.4 Gy were associated with poor OS. Among 21 EGFR-mutated patients, 3 year-OS rates were 64.7% in the CCRT+D cohort and 100% in the CCRT cohort, while 3 year-OS rates were 68.8% and 58.7% among 90 EGFR wild-type patients. Three-year OS rates were 64.6% and 47.6% for EDIC < 4.4 Gy and EDIC ≥ 4.4 Gy in the overall cohort (HR, 1.82; 95% CI, 1.14-2.90; P = 0.015). In the subgroup analysis, 66.3% vs. 44.4% in the CCRT+D cohort (HR, 2.01; 95% CI, 1.17-3.47; P = 0.016), and 59.0% vs. 56.1% in the CCRT cohort (HR, 1.20; 95% CI, 0.48-3.01; P = 0.70), respectively.

CONCLUSION

Our real-world data in Japan showed that there was no significant difference in OS between the CCRT+D cohort and the CCRT cohort. High EDIC could be a risk for poor OS in patients treated with CCRT and consolidation durvalumab compared with those treated with CCRT.

Dynamic tumor-tracking stereotactic body radiotherapy with real-time monitoring of liver tumors using a gimbal-mounted linac: A multi-institutional phase II study

Background and purpose

This prospective multicenter phase II study aimed to evaluate the safety and efficacy of dynamic tumor tracking (DTT) stereotactic body radiotherapy (SBRT) with real-time monitoring of liver tumors using a gimbal-mounted system.

Materials and methods

Patients with < 4 primary or metastatic liver tumors with diameters ≤ 50 mm and expected to have a respiratory motion of ≥ 10 mm were eligible. The prescribed dose was 40 Gy in five fractions. The primary endpoint was local control (LC) at 2 years. The secondary endpoints were overall survival (OS), progression-free survival (PFS), treatment-related toxicity, and tracking accuracy.

Results

Between September 2015 and March 2019, 48 patients (48 lesions) with a median age of 74 years were enrolled from four institutions. Of these, 39 were diagnosed with hepatocellular carcinoma and nine with metastatic liver cancer. The median tumor diameter was 17.5 mm. DTT-SBRT was successfully performed in all patients; the median treatment time was 28 min/fraction. The median follow-up period was 36.5 months. The 2-year LC, OS, and PFS rates were 98.0 %, 88.8 %, and 55.1 %, respectively. Disease progression was observed in 33 (68.8 %) patients. One patient (0.2 %) had local recurrence, 31 (64.6 %) developed new hepatic lesions outside the irradiation field, and nine (18.8 %) had distant metastases (including overlap). Grade 3 late adverse events were observed in seven patients (14.5 %). No grade 4 or 5 treatment-related toxicity was observed. The median tracking accuracy was 2.9 mm.

Conclusion

Employing DTT-SBRT to treat liver tumors results in excellent LC with acceptable adverse-event incidence.

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.

Perianal Bowen's disease treated with radiotherapy preserving anal function with a unique skin reaction considered as 'tumoritis'

Bowen's disease (BD) is a form of intraepidermal squamous cell carcinoma (SCC), and it occasionally occurs on the perianal site. BD is often treated with surgical excision; however, sometimes surgical excision for perianal BD cannot preserve anal function. We report the case of a 72-year-old man presenting with perianal pain and BD. He was treated with Radiotherapy (RT) and preserved his normal anal sphincter function without any recurrence or late adverse event. Moreover, we observed the unique skin reaction called 'tumoritis', which is characterized by mucosal inflammation. Tumoritis indicates the true extent of the tumor and evaluating the tumor or lesion size based on the extent of tumoritis when performing RT is important.

Multi-institutional phase II study of ultra-hypofractionated whole-breast irradiation after breast-conserving surgery for breast cancer in Japan: Kyoto Radiation Oncology Study Group (UPBEAT study)

PURPOSE

The UK-FAST-Forward study showed that ultra-hypofractionated whole-breast irradiation (ultra-HF-WBI) involving five fractions of 26 Gy radiation over 1 week was not inferior to HF-WBI. However, it is not used in Japan due to safety concerns. In April 2022, we commenced a multi-institutional, single-arm, phase II trial. Our aim is to confirm the safety of ultra-HF-WBI after breast-conserving surgery (BCS) for breast cancer in Japanese women.

METHOD

We plan to enroll 98 patients from 13 institutions. The primary endpoint is the proportion of late adverse events of grades ≥2 within 3 years.

DISCUSSION

We believe that this highly promising clinical study can positively impact the Japanese guidelines for breast cancer treatment. The results will help us decide whether or not ultra-HF-WBI can be used as a more convenient alternative to WBI.

REGISTRATION NUMBER AND DATE

This trial was registered in the UMIN Clinical Trials Registry (UMIN000047080) on March 4, 2022.

Prospective multicenter cohort study of durvalumab for patients with unresectable stage III non-small cell lung cancer and grade 1 radiation pneumonitis

OBJECTIVE

Durvalumab was safe and effective in patients with unresectable stage III non-small cell lung cancer (NSCLC) after concurrent chemoradiotherapy (CCRT) in a phase 3 trial (PACIFIC trial). Although a history of radiation pneumonitis (RP) has been reported to increase the risk of exacerbation of pneumonitis associated with programmed death-1 axis inhibitors, the detailed clinical results of durvalumab treatment in patients with baseline grade 1 RP were not reported in the PACIFIC trial. Therefore, we aimed to evaluate the safety and effectiveness of durvalumab therapy in these patients.

MATERIALS AND METHODS

This was a multicenter prospective cohort study involving 35 patients. Patients were eligible if they met the following criteria: inoperable stage III NSCLC, administration of durvalumab within 42 days after CCRT using platinum-based chemotherapy, no disease progression after CCRT, Eastern Cooperative Oncology Group performance status of 0-1, and presence of grade 1 RP at baseline. We assessed the effectiveness and safety of durvalumab with a minimum 1-year follow-up period for all patients.

RESULTS

Thirty-five patients were enrolled in our study from February 2019 to December 2019. The median progression-free survival was 11.4 months (95 % confidence interval, 7.1 months-not reached), and the median overall survival was not reached. Eleven (31 %) patients had grade ≥2 pneumonitis/RP, 10 (28 %) developed grade 2 pneumonitis/RP, and 1 (3 %) developed grade 5 pneumonitis/RP. Five (14 %) patients experienced treatment-related grade ≥3 adverse events.

CONCLUSION

Durvalumab might be safe and effective in patients with stage III NSCLC with baseline grade 1 RP following chemoradiotherapy.

Multi-institutional phase II study on the safety and efficacy of dynamic tumor tracking-stereotactic body radiotherapy for lung tumors

BACKGROUND AND PURPOSE

This study aimed to evaluate the safety and efficacy of dynamic tumor tracking-stereotactic body radiotherapy (DTT-SBRT) for lung tumors.

MATERIALS AND METHODS

Patients with cStage I primary lung cancer or metastatic lung cancer with an expected range of respiratory motion of ≥10 mm were eligible for the study. The prescribed dose was 50 Gy in four fractions. A gimbal-mounted linac was used for DTT-SBRT delivery. The primary endpoint was local control at 2 years.

RESULTS

Forty-eight patients from four institutions were enrolled in this study. Forty-two patients had primary non-small-cell lung cancer, and six had metastatic lung tumors. DTT-SBRT was delivered for 47 lesions in 47 patients with a median treatment time of 28 min per fraction. The median respiratory motion during the treatment was 13.7 mm (range: 4.5-28.1 mm). The motion-encompassing method was applied for the one remaining patient due to the poor correlation between the abdominal wall and tumor movement. The median follow-up period was 32.3 months, and the local control at 2 years was 95.2% (lower limit of the one-sided 85% confidence interval [CI]: 90.3%). The overall survival and progression-free survival at 2 years were 79.2% (95% CI: 64.7%-88.2%) and 75.0% (95% CI: 60.2%-85.0%), respectively. Grade 3 toxicity was observed in one patient (2.1%) with radiation pneumonitis. Grade 4 or 5 toxicity was not observed.

CONCLUSION

DTT-SBRT achieved excellent local control with low incidences of severe toxicities in lung tumors with respiratory motion.

Development of AI-driven prediction models to realize real-time tumor tracking during radiotherapy

BACKGROUND

In infrared reflective (IR) marker-based hybrid real-time tumor tracking (RTTT), the internal target position is predicted with the positions of IR markers attached on the patient's body surface using a prediction model. In this work, we developed two artificial intelligence (AI)-driven prediction models to improve RTTT radiotherapy, namely, a convolutional neural network (CNN) and an adaptive neuro-fuzzy inference system (ANFIS) model. The models aim to improve the accuracy in predicting three-dimensional tumor motion.

METHODS

From patients whose respiration-induced motion of the tumor, indicated by the fiducial markers, exceeded 8 mm, 1079 logfiles of IR marker-based hybrid RTTT (IR Tracking) with the gimbal-head radiotherapy system were acquired and randomly divided into two datasets. All the included patients were breathing freely with more than four external IR markers. The historical dataset for the CNN model contained 1003 logfiles, while the remaining 76 logfiles complemented the evaluation dataset. The logfiles recorded the external IR marker positions at a frequency of 60 Hz and fiducial markers as surrogates for the detected target positions every 80-640 ms for 20-40 s. For each logfile in the evaluation dataset, the prediction models were trained based on the data in the first three quarters of the recording period. In the last quarter, the performance of the patient-specific prediction models was tested and evaluated. The overall performance of the AI-driven prediction models was ranked by the percentage of predicted target position within 2 mm of the detected target position. Moreover, the performance of the AI-driven models was compared to a regression prediction model currently implemented in gimbal-head radiotherapy systems.

RESULTS

The percentage of the predicted target position within 2 mm of the detected target position was 95.1%, 92.6% and 85.6% for the CNN, ANFIS, and regression model, respectively. In the evaluation dataset, the CNN, ANFIS, and regression model performed best in 43, 28 and 5 logfiles, respectively.

CONCLUSIONS

The proposed AI-driven prediction models outperformed the regression prediction model, and the overall performance of the CNN model was slightly better than that of the ANFIS model on the evaluation dataset.

Clinical results of dynamic tumor-tracking stereotactic body radiotherapy with real-time monitoring for liver tumors using a gimbal-mounted linac: A multi-institutional phase II study

441

Background: Dynamic tumor-tracking (DTT) stereotactic body radiotherapy (SBRT) with real-time monitoring for liver tumors using a gimbal-mounted linac can decrease the normal liver dose and planning target volume (PTV) without sacrificing the target dose. We hypothesized that this method would yield excellent tumor control comparable to that by the conventional SBRT. We conducted a multi-institutional prospective phase II study to evaluate the safety and efficacy of DTT-SBRT for liver tumors (UMIN-CTR, UMIN000017886). Methods: The main eligibility criteria were as follows: (1) < 4 liver tumors; (2) technical difficulties with percutaneous ablation therapies, inoperable lesions, or patient refusal to undergo surgery; (3) Eastern Cooperative Oncology Group performance status of 0–2; (4) Child-Pugh score of ≤8; and (5) respiratory motion of ≥10 mm. The primary endpoint was the local control rate (LC) at 2 years (expected endpoint: > 90%), and the secondary endpoints were overall survival rate (OS), progression-free survival rate (PFS), and treatment-related toxicity. We performed DTT-SBRT with 40 Gy in 5 fractions prescribed to the PTV D95, and a maximum dose of 55−58 Gy using 7–9 static non-coplanar ports of the 6-MV beam was applied. The Kaplan-Meier analysis was performed to estimate the OS and LC. Treatment-related toxicity was scored according to the Common Terminology Criteria for Adverse Events v.4.0. Results: Forty-eight patients (48 tumors) were registered from four institutes and successfully treated between September 2015 and March 2019. Their median age was 74 years (range, 52–97). Thirty-nine tumors were hepatocellular carcinomas, and nine were metastatic liver tumors. The median tumor size was 5.8 ml (range, 0.7–64.1). At the time of data cutoff on March 31, 2021, the median follow-up period was 36.5 months (range, 3.0–62.4). The 2-year LC was 98.0%. Two-year OS and PFS were 88.8% and 55.1%, respectively. Recurrences were observed in 33 patients (68.5%). One patient (0.2%) had local recurrence, 30 (62.5%) developed new hepatic lesions outside of the irradiation field, and 9 (18.8%) had distant metastases. Grade 3 adverse events were observed in seven patients, including elevation of liver or biliary enzyme levels and hematopoietic adverse events. No treatment-related toxicity of grade 4 or higher was observed. Conclusions: Employing DTT-SBRT to treat liver tumors resulted in excellent LC with acceptable incidence of adverse events. This method will be a promising alternative therapy for patients who cannot receive surgery or percutaneous ablation therapy. To the best of our knowledge, this is the first phase II trial evaluating DTT-SBRT for liver tumors. Clinical trial information: UMIN000017886.

Real-world survey of pneumonitis and its impact on durvalumab consolidation therapy in patients with non-small cell lung cancer who received chemoradiotherapy after durvalumab approval (HOPE-005/CRIMSON)

OBJECTIVES

The incidence of real-world pneumonitis and durvalumab rechallenge during chemoradiotherapy and durvalumab consolidation for non-small cell lung cancer is unknown.

MATERIALS AND METHODS

We retrospectively evaluated the medical records of 302 consecutive patients diagnosed with non-small cell lung cancer who started chemoradiotherapy between May 2018 and May 2019.

RESULTS

Median age was 70 (range: 40-87) years. Volume of lung parenchyma that received 20 Gy (V20) exceeded 35% in 2% and mean lung dose exceeded 20 Gy in 1% of patients. Durvalumab consolidation was delivered to 225 patients (75%). Overall, 83% (n = 251), 34% (n = 103), 7% (n = 21), and 1% (n = 4) of the patients developed any grade of pneumonitis, symptomatic pneumonitis, ≥grade 3 pneumonitis, and fatal (grade 5) pneumonitis, respectively. Corticosteroids were administered to 25% of the patients to treat pneumonitis. Multivariate analysis identified the predictive factors for the development of symptomatic pneumonitis: V20 Gy or more ≥ 25% (odds ratio [OR]: 2.37, P = 0.008) and mean lung dose (MLD) ≥ 10 Gy (OR: 1.93, P < 0.0047). Of the 52 patients who received corticosteroids for pneumonitis after durvalumab initiation, 21 were rechallenged with durvalumab. Overall, 81% of patients met the PACIFIC study's rechallenge criteria and did not experience a severe pneumonitis relapse.

CONCLUSION

High V20 and MLD were independent risk factors of symptomatic pneumonitis. More than 80% of the patients who were rechallenged with durvalumab after pneumonitis met the PACIFIC study's rechallenge criteria. Consequently, severe relapse did not occur. Cooperation between radiation and medical oncologists is important for safe chemoradiotherapy and the safe completion of durvalumab consolidation therapy.

Impact of pre-treatment C-reactive protein level and skeletal muscle mass on outcomes after stereotactic body radiotherapy for T1N0M0 non-small cell lung cancer: a supplementary analysis of the Japan Clinical Oncology Group study JCOG0403

This study aimed to evaluate the impact of pretreatment C-reactive protein (CRP) and skeletal muscle mass (SMM) on outcomes after stereotactic body radiotherapy (SBRT) for T1N0M0 non-small cell lung cancer (NSCLC) as a supplementary analysis of JCOG0403. Patients were divided into high and low CRP groups with a threshold value of 0.3 mg/dL. The paraspinous musculature area at the level of the 12th thoracic vertebra was measured on simulation computed tomography (CT). When the area was lower than the sex-specific median, the patient was classified into the low SMM group. Toxicities, overall survival (OS) and cumulative incidence of cause-specific death were compared between the groups. Sixty operable and 92 inoperable patients were included. In the operable cohort, OS significantly differed between the CRP groups (log-rank test p = 0.009; 58.8% and 83.6% at three years for high and low CRP, respectively). This difference in OS was mainly attributed to the difference in lung cancer deaths (Gray's test p = 0.070; 29.4% and 7.1% at three years, respectively). No impact of SMM on OS was observed. The incidence of Grade 3-4 toxicities tended to be higher in the low SMM group (16.7% vs 0%, Fisher's exact test p = 0.052). In the inoperable cohort, no significant impact on OS was observed for either CRP or SMM. The toxicity incidence was also not different between the CRP and SMM groups. The present study suggests that pretreatment CRP level may provide prognostic information in operable patients receiving SBRT for early-stage NSCLC.

Multicenter prospective study of stereotactic body radiotherapy for previously untreated solitary primary hepatocellular carcinoma: The STRSPH study

AIM

To prospectively evaluate the efficacy and safety of stereotactic body radiotherapy (SBRT) for patients with previously untreated solitary primary hepatocellular carcinoma (HCC).

METHODS

The main eligibility criteria included the following: (1) primary solitary HCC; (2) no prior treatment for HCC; (3) Child-Turcotte-Pugh score of seven or less; and (4) unsuitability for or refusal of surgery and radiofrequency ablation (RFA). The prescribed dose of SBRT was 40 Gy in five fractions. The primary endpoint was 3-year overall survival (OS); the secondary endpoints included local progression-free survival (LPFS), local control (LC), and adverse events. The accrual target was 60 patients, expecting a 3-year OS of 70% with a 50% threshold.

RESULTS

Between 2014 and 2018, 36 patients were enrolled; enrollment was closed early because of slow accrual. The median tumor size was 2.3 cm. The median follow-up at the time of evaluation was 20.8 months. The 3-year OS was 78% (95% confidence interval [CI]: 53%-90%). The 3-year LPFS and LC proportion were 73% (95% CI: 48%-87%) and 90% (95% CI: 65%-97%), respectively. Grade 3 or higher SBRT-related toxicities were observed in four patients (11%), and grade five toxicities were not observed.

CONCLUSIONS

This study showed acceptably low incidence of SBRT-related toxicities. LC and OS after SBRT were comparable for previously untreated solitary HCC for patients unfit for resection and RFA. Although a definitive conclusion cannot be drawn by this study, the promising results indicate that SBRT may be an alternative option in the management of early HCC.

Multi-institutional dose-segmented dosiomic analysis for predicting radiation pneumonitis after lung stereotactic body radiation therapy

PURPOSE

To predict radiation pneumonitis (RP) grade 2 or worse after lung stereotactic body radiation therapy (SBRT) using dose-based radiomic (dosiomic) features.

METHODS

This multi-institutional study included 247 early-stage nonsmall cell lung cancer patients who underwent SBRT with a prescribed dose of 48-70 Gy at an isocenter between June 2009 and March 2016. Ten dose-volume indices (DVIs) were used, including the mean lung dose, internal target volume size, and percentage of entire lung excluding the internal target volume receiving greater than x Gy (x = 5, 10, 15, 20, 25, 30, 35, and 40). A total of 6,808 dose-segmented dosiomic features, such as shape, first order, and texture features, were extracted from the dose distribution. Patients were randomly partitioned into two groups: model training (70%) and test datasets (30%) over 100 times. Dosiomic features were converted to z-scores (standardized values) with a mean of zero and a standard deviation (SD) of one to put different variables on the same scale. The feature dimension was reduced using the following methods: interfeature correlation based on Spearman's correlation coefficients and feature importance based on a light gradient boosting machine (LightGBM) feature selection function. Three different models were developed using LightGBM as follows: (a) a model with ten DVIs (DVI model), (b) a model with the selected dosiomic features (dosiomic model), and (c) a model with ten DVIs and selected dosiomic features (hybrid model). Suitable hyperparameters were determined by searching the largest average area under the curve (AUC) value in the receiver operating characteristic curve (ROC-AUC) via stratified fivefold cross-validation. Each of the final three models with the closest the ROC-AUC value to the average ROC-AUC value was applied to the test datasets. The classification performance was evaluated by calculating the ROC-AUC, AUC in the precision-recall curve (PR-AUC), accuracy, precision, recall, and f1-score. The entire process was repeated 100 times with randomization, and 100 individual models were developed for each of the three models. Then the mean value and SD for the 100 random iterations were calculated for each performance metric.

RESULTS

Thirty-seven (15.0%) patients developed RP after SBRT. The ROC-AUC and PR-AUC values in the DVI, dosiomic, and hybrid models were 0.660 ± 0.054 and 0.272 ± 0.052, 0.837 ± 0.054 and 0.510 ± 0.115, and 0.846 ± 0.049 and 0.531 ± 0.116, respectively. For each performance metric, the dosiomic and hybrid models outperformed the DVI models (P < 0.05). Texture-based dosiomic feature was confirmed as an effective indicator for predicting RP.

CONCLUSIONS

Our dose-segmented dosiomic approach improved the prediction of the incidence of RP after SBRT.

Durvalumab for patients with unresectable stage III non-small cell lung cancer and grade 1 radiation pneumonitis following concurrent chemoradiotherapy: a multicenter prospective cohort study

Introduction/Background Durvalumab demonstrated a good efficacy and safety in patients with unresectable stage III non-small cell lung cancer (NSCLC) after concurrent chemoradiotherapy (CCRT) in the PACIFIC trial. Although a history of radiation pneumonitis (RP) has been reported to increase the risk of pneumonitis associated with programmed death-1 inhibitors, the safety and efficacy of durvalumab in patients with baseline Grade 1 RP have not been assessed. Therefore, we carried out a multicenter prospective cohort study to evaluate the efficacy and safety of durvalumab in these patients. Patients and Methods This was a multicenter prospective cohort study of 35 patients with Grade 1 RP after CCRT and before durvalumab initiation. This study was a first prespecified analysis for the first 20 patients with the primary objective of assessing the short-term safety; it was assessed 3 months after durvalumab initiation. Results Twenty patients were enrolled in this study between March 1, 2019, and September 3, 2019. Three patients (15%) experienced drug-related Grade ≥3 adverse events, while three patients (15%) had Grade ≥2 pneumonitis/RP within 3 months after durvalumab initiation. Three months after durvalumab initiation, all the patients were alive and four patients (20%) experienced disease progression. Conclusion Durvalumab can be a feasible treatment option for patients with stage III NSCLC with baseline Grade 1 RP following CCRT.(Trial registration number: UMIN000036061. The registration period was between March 2019 and December 2019.).

Application and limitation of radiomics approach to prognostic prediction for lung stereotactic body radiotherapy using breath-hold CT images with random survival forest: A multi-institutional study

PURPOSE

To predict local recurrence (LR) and distant metastasis (DM) in early stage non-small cell lung cancer (NSCLC) patients after stereotactic body radiotherapy (SBRT) in multiple institutions using breath-hold computed tomography (CT)-based radiomic features with random survival forest.

METHODS

A total of 573 primary early stage NSCLC patients who underwent SBRT between January 2006 and March 2016 and met the eligibility criteria were included in this study. Patients were divided into two datasets: training (464 patients in 10 institutions) and test (109 patients in one institution) datasets. A total of 944 radiomic features were extracted from manually segmented gross tumor volumes (GTVs). Feature selection was performed by analyzing inter-segmentation reproducibility, GTV correlation, and inter-feature redundancy. Nine clinical factors, including histology and GTV size, were also used. Three prognostic models (clinical, radiomic, and combined) for LR and DM were constructed using random survival forest (RSF) to deal with total death as a competing risk in the training dataset. Robust models with optimal hyper-parameters were determined using fivefold cross-validation. The patients were dichotomized into two groups based on the median value of the patient-specific risk scores (high- and low-risk score groups). Gray's test was used to evaluate the statistical significance between the two risk score groups. The prognostic power was evaluated by the concordance index with the 95% confidence intervals (CI) via bootstrapping (2000 iterations).

RESULTS

The concordance indices at 3 yr of clinical, radiomic, and combined models for LR were 0.57 [CI: 0.39-0.75], 0.55 [CI: 0.38-0.73], and 0.61 [CI: 0.43-0.78], respectively, whereas those for DM were 0.59 [CI: 0.54-0.79], 0.67 [CI: 0.54-0.79], and 0.68 [CI: 0.55-0.81], respectively, in the test dataset. The combined DM model significantly discriminated its cumulative incidence between high- and low-risk score groups (P < 0.05). The variable importance of RSF in the combined model for DM indicated that two radiomic features were more important than other clinical factors. The feature maps generated on the basis of the most important radiomic feature had visual difference between high- and low-risk score groups.

CONCLUSIONS

The radiomics approach with RSF for competing risks using breath-hold CT-based radiomic features might predict DM in early stage NSCLC patients who underwent SBRT although that may not have potential to predict LR.

Real-world survey of pneumonitis/radiation pneumonitis among patients with locally advanced non-small cell lung cancer treated with chemoradiotherapy after durvalumab approval: A multicenter retrospective cohort study (HOPE-005/CRIMSON)

9039

Background: Durvalumab was approved as a consolidation therapy after chemoradiotherapy (CRT) for locally advanced non-small cell lung cancer (NSCLC) and established as the standard of care. However, since the approval of durvalumab, little has been reported on the frequency, severity, or clinical course of pneumonitis/radiation pneumonitis throughout the course of CRT. Methods: We conducted a 17-center, retrospective cohort study of consecutive patients with locally advanced NSCLC who received concurrent chemoradiotherapy (CCRT) with platinum-based chemotherapy between May 2018 and May 2019. Results: A total of 275 patients were included; their median age was 69.9 (range, 40.3-87.5), mean V20 was 19.4% (range, 1.4-37.9), and mean "mean lung dose" was 10.9 Gy (range, 1.5-31.3). Of these, 204 patients received durvalumab consolidation therapy (74.2%). Median follow-up time from the initiation of CCRT was 8.4 months (range, 1.5-15.7). During follow-up, 225 patients (81.8%) developed any-grade pneumonitis/radiation pneumonitis. Of these, more than half (134 of 225) were asymptomatic (grade 1), 18 (6.5%) were ≥grade 3, and 4 patients (1.5%) had fatal pneumonitis/radiation pneumonitis. By the time of initial assessment of response to CCRT, 64 (23.3%) patients had developed radiation pneumonitis. Logistic regression revealed that only V20 ≥25 % was an independent risk factor of symptomatic (≥grade 2) pneumonitis/radiation pneumonitis (OR: 2.74, 95% CI: 1.35-5.53, p = 0.0045). Of the 275 patients, 67 were treated with corticosteroids for pneumonitis/radiation pneumonitis (24.7%), and 14 (5.1%) needed home oxygen therapy after the treatment of pneumonitis/radiation pneumonitis. Among patients treated with corticosteroids, 21 patients received durvalumab rechallenge. Of the 21 patients, 6 (29%) showed pneumonitis/radiation pneumonitis relapse, of which 3 (14%) resulted in suspension of durvalumab rechallenge, but none were fatal. Conclusions: Although over four-fifths of the patients treated with CCRT after the approval of durvalumab developed pneumonitis/radiation pneumonitis, more than half of them were asymptomatic, and ≥grade 3 events accounted for 6.5%. Sometimes patients needed corticosteroid therapy, which was in many occasions effective, and some also underwent durvalumab rechallenge. V20 was an independent risk factor of symptomatic pneumonitis/radiation pneumonitis.

Predictive value of the Lung Immune Prognostic Index (LIPI) in locally advanced non-small-cell lung cancer (NSCLC) patients treated with concurrent chemoradiotherapy (CCRT) in the multicenter retrospective study

e21076

Background: PD-L1 inhibitor, durvalumab has been approved since the PACIFIC study showed its efficacy as consolidation therapy after CCRT for locally advanced NSCLC. But predictive factor for the efficacy of CCRT on this post PACIFIC era have not been known. LIPI has been proposed as a new biomarker for the anti-PD-1 therapy of advanced NSCLC. In this study, we investigated the usefulness of LIPI as a predictive marker in multicenter cohort of patients with locally advanced NSCLC who received CCRT as initial treatment. Methods: 219 patients with available baseline LIPI were reviewed. The progression free survival (PFS) was estimated by the Kaplan-Meier method, and LIPI were calculated at baseline. Kaplan-Meier estimates of PFS and recurrence were compared using the log-rank test for trend. Multivariable analysis was conducted using the Cox and logistic regression models, respectively, adjusted for age, sex, ECOG-PS, smoking, histology, TNM stage, chemotherapy regimens, Body mass index (BMI), PD-L1 status, EGFR or ALK mutation, and baseline LIPI. Results: 62.5% (n = 137) of the patients had a good (0 factors) LIPI, while 37.5% (n = 82) had intermediate (1 factor) and poor (2 factors) LIPI respectively. In multivariable analysis, good LIPI (0 factors) were significantly associated with longer PFS (HR = 0.46, 95% CI 0.28-0.75; P < 0.01) as did ECOG-PS0 (P < 0.01), ≤stageIIIA (P < 0.01), being treated with durvalumab after CRT (P = 0.04). There were no difference in the patient characteristics between good LIPI and intermediate/poor LIPI, significantly. Higher LIPI (1 or 2 factors) were strongly prognostic factor for recurrence after CCRT in multivariate analysis (P = 0.04), along with ECOG-PS1≤ (P < 0.01), stage IIIB≤ (P < 0.01). Conclusions: The good LIPI predictive value for PFS and disease control in patients treated with CCRT was confirmed. Although a strong statistical significance, we needs to be confirmed further with longer follow-up and prospective study.

P103 Heart failure with preserved ejection fruction defines the progression of abnormal brain aging: a prospective study of young-old hypertensive patients

Funding Acknowledgements

Ministry of Health, Labor and Welfare (MHLW) Geriatrics and Gelontorogy sponsored research funds

Background & purpose: Recently, many longitudinal studies have shown that heart failure with reduced ejection fraction (HFrEF) is associated with various types of brain abnormalities: cerebral micro-bleeding, atrophy, or pathologic degeneration (white matter hyperintensity; WMH). These brain abnormalities are known to increase with aging and to be closely associated with cognitive impairment. Heart failure with preserved ejection fraction (HFpEF) also increases with aging, but there have been few longitudinal studies to address the relationship between HFpEF and brain abnormalities. Thus, this longitudinal study aimed to clarify this relationship by focusing on WMH volume.

METHODS

The participants were 111 well-controlled hypertensive patients aged between 65 and 75 years with normal LV contraction and no history of symptomatic heart failure, ischemic heart disease, atrial fibrillation, stroke, or cognitive dysfunction. The participants were classified into 3 groups: Low E/e", E/e" &lt; 8; Middle E/e", 8≤ E/e" ≤ 15; and High E/e", E/e" &gt; 15. WMH volume was quantified on brain magnetic resonance imaging using analytical software.

RESULTS

During the mean 2.6 ± 1.0-year follow-up period, the rate of increase of WMH volume was significantly higher in the high E/e" group (1.1 ± 1.2 mL/year) than in the low E/e" group (0.30 ± 0.78 mL/year; P = 0.0238). Linear regression analysis including other confounders showed that the only positive association was between the rate of increase of WMH volume and the E/e" ratio (beta- coefficient = 0.225, P = 0.018).

CONCLUSION

The severity of LV diastolic dysfunction is positively correlated with increasing WMH volume.

Abstract P103 Figure. The rates of increase of WMH volumes

P768Cardiopulmonary exercise testing for assessing frailty status in stable elderly patients with heart failure

Introduction

Frailty is a syndrome associated with aging that produces subclinical dysfunction across multiple organ systems and leads to increased risk of mortality. The Kihon Checklist (KCL) was developed by the Japanese Ministry of Health, Labor and Welfare to identify older persons in need of care; it is a reliable tool for predicting general frailty in older adults. There is little information about the relationship between frailty status and exercise capacity.

Purpose

To investigate whether cardiopulmonary exercise testing (CPX) parameters are associated with frailty in stable elderly patients with heart failure (HF).

Methods

Ninety-two stable elderly patients with HF were evaluated by using CPX and the total KCL (t-KCL). A t-KCL score of 0–3 was classified as robust, 4–7 as pre-frail, and ≥8 as frail. Diagnostic performance (DP) -plot analysis was used to assess the utility of CPX parameters to distinguish between the presence and absence of frailty.

Results

Mean age, left ventricular ejection fraction, plasma brain natriuretic peptide, peak work rate (WR), peak VO2, and t-KCL score were 81.7 years, 57.8%, 182 pg/mL, 49.6 W, 13.2 mL/kg/min, and 10.7, respectively. t-KCL score was significantly correlated with peak VO2 (r=−0.53, p<0.001) and peak WR (r=−0.63, p<0.001). In the patients with frailty (n=63), peak WR was significantly lower than that in patients without frailty (n=29; 40.8 and 71.0 W, respectively, p<0.001). Multivariate analysis revealed that peak WR was the only significant independent predictor of frailty (β=−0.111, p<0.001). In the DP-plot analysis, a cut-off value for peak WR of 51.9 W was the best predictor of frailty (accuracy; 0.706, Figure).

Cut-off value for peak WR

Conclusions

Frailty status was significantly associated with peak WR in stable elderly patients with HF. CPX may be useful for assessing frailty status in stable elderly patients with HF.

Salvage Pulmonary Operations Following Stereotactic Body Radiotherapy for Small Primary and Metastatic Lung Tumors: Evaluation of the Operative Procedures

Stereotactic body radiotherapy is an alternative treatment option for small-sized, primary lung cancers and pulmonary metastatic diseases. In the case of local relapse after stereotactic body radiotherapy, salvage pulmonary resection is considered cautiously. However, no study has described the difficulty of the salvage operations. This study aimed to assess the difficulty associated with salvage operative procedures. Eight patients who developed local relapse after stereotactic body radiotherapy and had undergone salvage pulmonary operations were enrolled in this study (stereotactic body radiotherapy group). Additionally, 439 patients who underwent video-assisted thoracoscopic lobectomy without previous stereotactic body radiotherapy were enrolled as the standard operative control group (non-stereotactic body radiotherapy group). In the stereotactic body radiotherapy group, 1 of the 8 patients had undergone lobectomy with composite resection of the third and fourth ribs. Of the 8 patients, 6 had undergone video-assisted thoracoscopic lobectomy and 1 had been inoperable because of rapid tumor progression. The operation time and the incision length of the utility port were apt to be longer in the stereotactic body radiotherapy group than in the non-stereotactic body radiotherapy group. On the contrary, the duration of drain placement and the length of hospital stay after the operation were not different. Thus, the salvage pulmonary operations were performed in the usual video-assisted thoracoscopic lobectomy approach, but slightly complicated than the standard video-assisted thoracoscopic lobectomy. Although to decide the indication of salvage operation might be difficult, it could be a feasible treatment option in local relapse after stereotactic body radiotherapy.

Case Series of 23 Patients Who Developed Fatal Radiation Pneumonitis After Stereotactic Body Radiotherapy for Lung Cancer

The purpose of this study was to examine the characteristics and treatment plans of patients who experienced fatal radiation pneumonitis after stereotactic body radiation therapy for primary or oligometastatic lung cancer. Records of 1789 patients treated with stereotactic body radiation therapy for primary or oligometastatic lung cancer were retrospectively reviewed to identify those who developed fatal radiation pneumonitis. Twenty-three (1.3%; 18 men and 5 women) patients developed fatal radiation pneumonitis after stereotactic body radiation therapy for lung cancer; their median age was 74 years. The mean Krebs von den Lungen-6 level and percent vital capacity were 1320 U/mL and 82%, respectively. Prestereotactic body radiation therapy computed tomography revealed pulmonary interstitial change in 14 (73.7%) of 19 patients in whom computed tomography data could be reviewed. Seven (30.4%) of 23 patients had regularly used steroids. The median time duration between stereotactic body radiation therapy commencement and pneumonia symptom appearance was 75 (range: 14-204) days. Median survival time following pneumonia symptom appearance was 53 (range: 4-802) days. The 6- and 12-month overall survival rates were 34.8% and 13.0%, respectively. The 6-month overall survival rates in patients with and without heart disease were 50.0%, 16.7%, and 46.7% for heart disease existence, respectively. There were 4 patients in whom fatal radiation pneumonitis occurred within 2 months after stereotactic body radiation therapy and who died within 1 month. Three of them had no pulmonary interstitial change before stereotactic body radiation therapy, but had heart disease. In summary, the survival time in this case series was generally short but varied widely. More than half of the patients had pulmonary interstitial change before stereotactic body radiation therapy, although immediately progressive fatal radiation pneumonitis was also observed in patients without pulmonary interstitial change. True risk factors for fatal radiation pneumonitis should be examined in a prospective study with a larger cohort.

Final report of survival and late toxicities in the Phase I study of stereotactic body radiation therapy for peripheral T2N0M0 non-small cell lung cancer (JCOG0702)

Purpose

A dose escalation study to determine the recommended dose with stereotactic body radiation therapy (SBRT) for peripheral T2N0M0 non-small cell carcinomas (JCOG0702) was conducted. The purpose of this paper is to report the survival and the late toxicities of JCOG0702.

Materials and methods

The continual reassessment method was used to determine the dose level that patients should be assigned to and to estimate the maximum tolerated dose. The starting dose was 40 Gy in four fractions at D₉₅ of PTV.

Results

Twenty-eight patients were enrolled. Ten patients were treated with 40 Gy at D₉₅ of PTV, four patients with 45 Gy, eight patients with 50 Gy, one patient with 55 Gy and five patients with 60 Gy. Ten patients were alive at the last follow-up. Overall survival (OS) for all patients was 67.9% (95% CI 47.3–81.8%) at 3 years and 40.8% (95% CI 22.4–58.5%) at 5 years. No Grade 3 or higher toxicity was observed after 181 days from the beginning of the SBRT. Compared to the toxicities up to 180 days, chest wall related toxicities were more frequent after 181 days.

Conclusions

The 5-year OS of 40.8% indicates the possibility that SBRT for peripheral T2N0M0 non-small cell lung cancer is superior to conventional radiotherapy. The effect of the SBRT dose escalation on OS is unclear and further studies are warranted.

New Method of Flush Saphenofemoral Ligation that is Expected to Inhibit Varicose Vein Recurrence in the Groin: Flush Ligation Using the Avulsion Technique Method

Recently, with the spread of laser ablation therapy, it has been called into question whether flush ligation of the great saphenous vein (GSV) reduces varicose vein recurrence after surgery. Because we thought such recurrence was caused by a narrow branch resection area, we developed a new method of flush ligation (the avulsion technique method). Materials and Methods: A total of 214 limbs in 180 patients whose GSV had become varicose were studied. In our procedure, we dissect the GSV, lift its proximal stump, and expose the tributaries. We pull out the distal side of the tributaries without ligature as far as possible. We evaluate the area of subcutaneous ecchymosis within a 15-cm radius of the inguinal incision visually on the third post-operative day. Results: We were able to pull out over 10 cm per branch by this method. The area of subcutaneous ecchymosis was mostly less than 10%. No hematoma or pain was observed after the operation. Conclusion: This method was safe, with subcutaneous ecchymosis occurring only rarely. We expect this method to reduce saphenofemoral junction recurrence after the operation. (This is a translation of Jpn J Phlebol 2017; 28: 11–16.)

Stereotactic body radiotherapy to treat small lung lesions clinically diagnosed as primary lung cancer by radiological examination: A prospective observational study

OBJECTIVES

Even with advanced image guidance, biopsies occasionally fail to diagnose small lung lesions, which are highly suggestive of primary lung cancer by radiological examination. The aim of this study was to evaluate the outcome of stereotactic body radiotherapy (SBRT) to treat small lung lesions clinically diagnosed as primary lung cancer.

MATERIALS AND METHODS

This is a prospective, multi-institutional observation study. Strict inclusion and exclusion criteria were determined in a nation-wide consensus meeting and used to include patients who were clinically diagnosed with primary lung cancer using precise imaging modalities, for whom further surgical intervention was not feasible, who refused watchful waiting, and who were highly tolerable of SBRT with informed consent. SBRT was performed with 48 Gy in 4 fractions at the tumor isocenter.

RESULTS

From August 2009 to August 2014, 62 patients from 11 institutions were enrolled. Their median age was 80 years. The tumors ranged in size from 9 to 30 mm in diameter (median, 18 mm). The median follow-up interval was 55 months. The 3-year overall survival rate was 83.3% (95% confidence interval (CI) 71.1-90.7%) for all the patients and 94.7% (95% CI 68.1-99.2%) for the patients younger than 75 years. Local failure, regional lymph node metastases and distant metastases occurred in 4 (6.4%), 3 (4.8%) and 11 (17.7%) patients, respectively. Grades 3 and 4 toxicities were observed in 8 (12.9%) patients and 1 (1.6%) patient, respectively. No grade 5 toxicities were observed.

CONCLUSIONS

SBRT is safe and effective for patients with small lung lesions clinically diagnosed as primary lung cancer that satisfied the proposed strict indication criteria as previously reported. A prospective interventional study is required to ascertain if SBRT is an alternative strategy for these patients.

A feasibility study of independent verification of dose calculation for Vero4DRT using a Clarkson-based algorithm

Dose verification for a gimbal-mounted image-guided radiotherapy system, Vero4DRT (Mitsubishi Heavy Industries Ltd., Tokyo, Japan) is usually carried out by pretreatment measurement. Independent verification calculations using Monte Carlo methods for Vero4DRT have been published. As the Clarkson method is faster and easier to use than measurement and Monte Carlo methods, we evaluated the accuracy of an independent calculation verification program and its feasibility as a secondary check for Vero4DRT. Computed tomography (CT)-based dose calculation was performed using a modified Clarkson-based algorithm. In this study, 120 patients' treatment plans were collected in our institute. The treatments were performed using conventional irradiation for lung and prostate, 3-dimensional (3D) conformal stereotactic body radiotherapy (SBRT) for the lung, and intensity-modulated radiation therapy (IMRT) for the prostate. Differences between the treatment planning system (TPS) and the Clarkson-based independent dose verification software were computed, and confidence limits (CLs, mean ± 2 standard deviation %) for Vero4DRT were compared with the CLs for the C-arms linear accelerators in the previous study. The results of the CLs, the conventional irradiation, SBRT, and IMRT showed 2.2 ± 3.5% (CL of the C-arms linear accelerators: 2.4 ± 5.3%), 1.1 ± 1.7% (-0.3 ± 2.0%), 4.8 ± 3.7% (5.4 ± 5.3%), and -0.5 ± 2.5% (-0.1 ± 3.6%) differences, respectively. The dose disagreement between the TPS and CT-based independent dose verification software was less than the 5% action level of American Association of Physicists in Medicine (AAPM) Task Group 114 (TG114). The CLs for the gimbal-mounted Vero4DRT were similar to the deviations for C-arms linear accelerators.

Prevalence of hypothyroidism among patients with breast cancer treated with radiation to the supraclavicular field: a single-centre survey

Purpose

We investigated the prevalence of hypothyroidism (HT) in patients with breast cancer who received radiation therapy to the supraclavicular (SC) field to evaluate the effect of radiation on thyroid.

Methods

Between April 2007 and May 2016, consecutive patients with invasive breast cancer who received SC radiation were recruited. Thyroid-stimulating hormone (TSH) and free thyroxine (fT4) were measured between April and August 2016. On the basis of the radiation-planning CT images, thyroid volume was calculated and dose–volume parameters were estimated. The endpoints were the prevalence of HT as determined by high levels of TSH and low levels of fT4 in serum, and the prevalence of subclinical HT, determined by high-serum TSH and normal fT4.

Results

Among the 68 consecutive patients, 26 were excluded from evaluation (10 patients died, 6 had a history of previous thyroid disease and 10 were lost to follow-up). One (2.4%) and six (14.3%) of these patients had HT and subclinical HT, respectively, with a mean TSH level of 8.27 µU/mL. By univariate analysis, a predictive factor of HT and subclinical HT was a thyroid volume <8 cm³ (OR 6.44, 95% CI 1.14 to 36.6; p=0.043). Multivariate analysis also showed an association between thyroid volume <8 cm³ and HT or subclinical HT (OR 18.48, 95% CI 1.48 to 230.86; p=0.024).

Conclusions

The prevalence of HT in patients with breast cancer studied was relatively low. Although thyroid volume appeared to be a predictive marker of HT in this cohort, further prospective evaluation is needed.

Phase I study of stereotactic body radiation therapy for centrally located stage IA non-small cell lung cancer (JROSG10-1)

BACKGROUND

To investigate the maximum tolerated dose (MTD) and recommended dose (RD) of stereotactic body radiation therapy (SBRT) for centrally located stage IA non-small cell lung cancer (NSCLC).

METHODS

Five dose levels, ranging from of 52 to 68 Gy in eight fractions, were determined; the treatment protocol began at 60 Gy (level 3). Each dose level included 10 patients. Levels 1-2 were indicated if more than four patients exhibited dose-limiting toxicity (DLT), which was defined as an occurrence of a grade 3 (or worse) adverse effect within 12 months after SBRT initiation. MTD was defined as the lowest dose level at which more than four patients exhibited DLT.

RESULTS

Ten patients were enrolled in the level 3 study. One patient was considered unsuitable because of severe emphysema. Therefore, nine patients were evaluated and no patient exhibited DLT. The level 3 results indicated that we should proceed to level 4 (64 Gy). However, due to the difficulty involved in meeting the dose constraints, further dose escalation was not feasible and the MTD was found to be 60 Gy.

CONCLUSIONS

The RD of SBRT for centrally located stage IA NSCLC was 60 Gy in eight fractions.

Modifying the planning target volume to optimize the dose distribution in dynamic conformal arc therapy for large metastatic brain tumors

PURPOSE

When treating large metastatic brain tumors with stereotactic radiotherapy (SRT), high dose conformity to target is difficult to achieve. Employing a modified planning target volume (mPTV) instead of the original PTV may be one way to improve the dose distribution in linear accelerator-based SRT using a dynamic conformal technique. In this study, we quantitatively analyzed the impact of a mPTV on dose distribution.

MATERIALS AND METHODS

Twenty-four tumors with a maximum diameter of >2 cm were collected. For each tumor, two plans were created: one used a mPTV and the other did not. The mPTV was produced by shrinking or enlarging the original PTV according to the dose distribution in the original plan. The dose conformity was evaluated and compared between the plans using a two-sided paired t test.

RESULTS

The conformity index defined by the Radiation Therapy Oncology Group was 1.34 ± 0.10 and 1.41 ± 0.13, and Paddick's conformity index was 0.75 ± 0.05 and 0.71 ± 0.06, for the plans with and without a mPTV, respectively. All of these improvements were statistically significant (P < 0.05).

CONCLUSION

The use of a mPTV can improve target conformity when planning SRT for large metastatic brain tumors.

Development of a four-axis moving phantom for patient-specific QA of surrogate signal-based tracking IMRT

Purpose:

The purposes of this study were two-fold: first, to develop a four-axis moving phantom for patient-specific quality assurance (QA) in surrogate signal-based dynamic tumor-tracking intensity-modulated radiotherapy (DTT-IMRT), and second, to evaluate the accuracy of the moving phantom and perform patient-specific dosimetric QA of the surrogate signal-based DTT-IMRT.

Methods:

The four-axis moving phantom comprised three orthogonal linear actuators for target motion and a fourth one for surrogate motion. The positional accuracy was verified using four laser displacement gauges under static conditions (±40 mm displacements along each axis) and moving conditions [eight regular sinusoidal and fourth-power-of-sinusoidal patterns with peak-to-peak motion ranges (H) of 10–80 mm and a breathing period (T) of 4 s, and three irregular respiratory patterns with H of 1.4–2.5 mm in the left–right, 7.7–11.6 mm in the superior-inferior, and 3.1–4.2 mm in the anterior–posterior directions for the target motion, and 4.8–14.5 mm in the anterior–posterior direction for the surrogate motion, and T of 3.9–4.9 s]. Furthermore, perpendicularity, defined as the vector angle between any two axes, was measured using an optical measurement system. The reproducibility of the uncertainties in DTT-IMRT was then evaluated. Respiratory motions from 20 patients acquired in advance were reproduced and compared three-dimensionally with the originals. Furthermore, patient-specific dosimetric QAs of DTT-IMRT were performed for ten pancreatic cancer patients. The doses delivered to Gafchromic films under tracking and moving conditions were compared with those delivered under static conditions without dose normalization.

Results:

Positional errors of the moving phantom under static and moving conditions were within 0.05 mm. The perpendicularity of the moving phantom was within 0.2° of 90°. The differences in prediction errors between the original and reproduced respiratory motions were −0.1 ± 0.1 mm for the lateral direction, −0.1 ± 0.2 mm for the superior-inferior direction, and −0.1 ± 0.1 mm for the anterior–posterior direction. The dosimetric accuracy showed significant improvements, of 92.9% ± 4.0% with tracking versus 69.8% ± 7.4% without tracking, in the passing rates of γ with the criterion of 3%/1 mm (p < 0.001). Although the dosimetric accuracy of IMRT without tracking showed a significant negative correlation with the 3D motion range of the target (r = − 0.59, p < 0.05), there was no significant correlation for DTT-IMRT (r = 0.03, p = 0.464).

Conclusions:

The developed four-axis moving phantom had sufficient accuracy to reproduce patient respiratory motions, allowing patient-specific QA of the surrogate signal-based DTT-IMRT under realistic conditions. Although IMRT without tracking decreased the dosimetric accuracy as the target motion increased, the DTT-IMRT achieved high dosimetric accuracy.

Development of a four-dimensional Monte Carlo dose calculation system for real-time tumor-tracking irradiation with a gimbaled X-ray head

PURPOSE

To develop a four-dimensional (4D) dose calculation system for real-time tumor tracking (RTTT) irradiation by the Vero4DRT.

METHODS

First, a 6-MV photon beam delivered by the Vero4DRT was simulated using EGSnrc. A moving phantom position was directly measured by a laser displacement gauge. The pan and tilt angles, monitor units, and the indexing time indicating the phantom position were also extracted from a log file. Next, phase space data at any angle were created from both the log file and particle data under the dynamic multileaf collimator. Irradiation both with and without RTTT, with the phantom moving, were simulated using several treatment field sizes. Each was compared with the corresponding measurement using films. Finally, dose calculation for each computed tomography dataset of 10 respiratory phases with the X-ray head rotated was performed to simulate the RTTT irradiation (4D plan) for lung, liver, and pancreatic cancer patients. Dose-volume histograms of the 4D plan were compared with those calculated on the single reference respiratory phase without the gimbal rotation [three-dimensional (3D) plan].

RESULTS

Differences between the simulated and measured doses were less than 3% for RTTT irradiation in most areas, except the high-dose gradient. For clinical cases, the target coverage in 4D plans was almost identical to that of the 3D plans. However, the doses to organs at risk in the 4D plans varied at intermediate- and low-dose levels.

CONCLUSIONS

Our proposed system has acceptable accuracy for RTTT irradiation in the Vero4DRT and is capable of simulating clinical RTTT plans.