Prospective Trial of Stereotactic Body Radiation Therapy for Both Operable and Inoperable T1N0M0 Non-Small Cell Lung Cancer: Japan Clinical Oncology Group Study JCOG0403

Clinical outcomes of proton beam therapy for inoperable stage I-IIA non-small cell lung cancer: Japanese nationwide registry study

PURPOSE

Radiotherapy is the standard treatment for unresectable stage I-IIA non-small cell lung cancer (NSCLC). One treatment option within radiotherapy is proton beam therapy (PBT). Currently, a prospective observational study is being conducted at all proton therapy centers in Japan as part of a proton beam all-case registry. This study aimed to evaluate the outcomes of PBT for inoperable stage I-IIA NSCLC.

METHODS

We included patients with stage I-IIA (UICC 8th) NSCLC who had started PBT between May 2016 and June 2020. Overall survival (OS), progression-free survival (PFS), cumulative incidence of local failure (LF), and adverse events were evaluated. Prognostic factors were compared using log-rank test and Cox proportional hazards model. The cumulative incidence curves were compared using Gray's test.

RESULTS

A total of 309 patients were evaluated. The median follow-up period was 47 months, calculated using the reverse Kaplan-Meier method. The 3/5-year OS was 62.7 %/47.7 %, PFS was 52.9 %/40.0 %, and LF was 14.4 %/22.1 %. According to the stage, 3-year OS, PFS, and LF were 69.6 %, 58.7 %, 13.3 %, respectively, for stage IA; 55.3 %, 41.6 %, 15.6 %, respectively, for stage IB; 33.9 %, 41.5 %, 25.6 %, respectively, for stage IIA. Female sex and good performance status, absence of interstitial pneumonia, absence of double cancer, and T1 stage were favorable prognostic factors for OS in a multivariate analysis. Grade ≥ 4 adverse events were not observed.

CONCLUSION

This study provided real-world treatment outcomes of PBT for inoperable stage I-IIA NSCLC in Japan.

Comprehensive plan quality assessment of simplified volumetric-modulated arc therapy for lung stereotactic body radiotherapy

In lung stereotactic body radiation therapy, optimizing plan quality, including dosimetric quality and plan complexity, is paramount for mitigating adverse effects and enhancing dose delivery accuracy. This study evaluated the plan quality of dynamic conformal arc-based volumetric-modulated arc therapy (d-VMAT) as a simplified VMAT compared to conventional VMAT (c-VMAT) across various prescription isodose lines (PIL) and planning target volume (PTV) sizes. Twenty inoperable non-small cell lung cancer patients were retrospectively analyzed (PTV: 7.6-68.7 cm3). The prescribed dose comprised 48 Gy delivered in four fractions, encompassing 95% of the PTV, with the PIL ranging from 60 to 90% in 10% increments, using a 6X-flattening filter-free beam. The d-VMAT and c-VMAT plans were generated for each patient and PIL setting. Dose indices, including the conformity index (CI), gradient index (GI), and plan complexity, were assessed for each plan. The GI of d-VMAT closely mirrored that of c-VMAT at 60% and 70% PIL. Nevertheless, d-VMAT exhibited significantly higher GI values than c-VMAT at 80% and 90% PIL, particularly for smaller PTV sizes. Notably, d-VMAT demonstrated reduced plan complexity across all PIL compared to c-VMAT. Clinically, significant differences in CI and dose coverage between d-VMAT and c-VMAT were not observed across varying PIL settings in the range of 60-80%. The dose to the organs at risk with d-VMAT was comparable to that with c-VMAT, except at 90% PIL. In conclusion, the simplification of VMAT treatment plan using d-VMAT demonstrates superior plan quality across various PTV sizes at 60% and 70% PIL.

A Japanese national survey on IMRT/SBRT in 2023 by the JASTRO High-Precision External Beam Radiotherapy Group

The purpose of this study was to investigate the utilization and implementation of stereotactic body radiotherapy (SBRT) and intensity-modulated radiotherapy (IMRT) in Japan up to 2023. The survey was conducted by the Japanese Society for Radiation Oncology High-Precision External Beam Radiotherapy Group Subcommittee from December 2023 to February 2024. The study targeted patients treated with IMRT or SBRT between January 2021 and December 2022. A comprehensive web-based questionnaire was distributed to 880 facilities, with separate sections for radiation oncologists and medical physicists/radiotherapy technologists. A total of 360 facilities responded (response rate: 40.9%) for the section of radiation oncologists, and 405 facilities responded (response rate: 46.0%) for medical physicists/radiotherapy technologists, providing data on the implementation status, techniques, workload and challenges associated with IMRT and SBRT. Based on the responses in the section of radiation oncologists, IMRT was used in 68.6% of responding institutes, and SBRT in 87.8%. VMAT emerged as the most common IMRT technique (78.3%). The survey highlighted a high demand for medical physicists to perform IMRT (86.9%). Based on the responses in the section of medical physicists/radiotherapy technologists, 84.6% of the facilities that have not performed IMRT reported that the main reason was a lack of radiation oncologists. Furthermore, the survey also noted significant variations in prescribed doses and margin sizes across facilities, indicating the need for further standardization. High-precision radiation techniques such as IMRT and SBRT are getting popular, however, the facility requirements which mandate the presence of at least two radiation oncologists prevents IMRT from becoming more widespread in Japan.

Stereotactic reirradiation for in-field lung cancer recurrence after stereotactic ablative radiotherapy: A systematic review and meta-analysis

PURPOSE

There is paucity of data for thoracic in-field reirradiation with two courses of stereotactic ablative radiotherapy (SABR). This meta-analysis evaluates the safety and efficacy of repeat SABR as salvage therapy for in-field failures after definitive SABR.

MATERIALS AND METHODS

A systematic search of PubMed, Cochrane Library, MEDLINE, and EMBASE databases was conducted in accordance with PRISMA guidelines. Studies were included if they involved adult patients treated with salvage SABR for in-field recurrences of lung cancer following prior SABR. To address varying definitions of local failure, studies were included if recurrence occurred within the original planning target volume (PTV). Studies with out-of-field failures (>1 cm from PTV) or those using non-SABR techniques were excluded. Pooled 1- and 2-year local control (LC) rates, overall survival (OS), and toxicities were calculated using a random-effects model. Population-weighted linear regression was employed to assess the relationship between dosimetric and clinico-pathologic variables and patient outcomes.

RESULTS

Twelve studies involving 197 patients were included in the quantitative analysis. All patients received two courses of SABR, with a median total dose of 50 Gy in 5 fractions. Pooled 1- and 2-year LC rates were 78.2 % (95 % CI: 66-87 %) and 68.0 % (95 % CI: 55-79 %), respectively. Patients receiving a cumulative biologically effective dose (BED) ≥ 200 Gy had significantly higher LC rates (84.9 %, 95 % CI: 70-93 %) vs (64.9 %, 95 % CI: 54-75 %, p = 0.02). Median OS did not significantly differ between low and high BED groups, though there was a trend toward improved survival with higher BED (21.4 vs 32.6 months). The pooled median OS across all studies was 26.3 months (95 % CI: 25.4-27.1). Improved LC rates were associated with smaller tumours (<2 cm), higher BED from the initial treatment and longer interval (>12 months) between initial and repeat SABR (p < 0.01). Toxicities were minimal, with a pooled incidence of ≥ grade 2 pneumonitis at 6.4 % and only 0.10 % reporting ≥ grade 3 toxicity.

CONCLUSIONS

Salvage in-field reirradiation with SABR achieves high local control and low toxicity, particularly in patients receiving higher cumulative BED (≥200 Gy) and with longer intervals (≥12 months) between treatments. These results suggest that repeat SABR is a viable salvage option for selected patients. Further prospective studies are needed to optimise dosing and patient selection for safe and effective reirradiation.

Risk factors for radiation-induced rib fractures following proton beam therapy for stage I non-small cell lung cancer: a retrospective study

BACKGROUND

Understanding and managing radiation-induced adverse events is becoming increasingly important in hypofractionated radiotherapy due to the use of higher doses per fraction compared with conventional radiotherapy. Specifically, toxicities of hypofractionated proton and carbon-ion beam therapy are still unclear. We investigated the clinical, anatomical, and dosimetric risk factors for radiation-induced rib fractures (RIRFs) following passive-scattering proton beam therapy (PBT) for stage I non-small cell lung cancer (NSCLC).

METHODS

We retrospectively investigated patients with stage I NSCLC who underwent PBT with 66-70 Gy (relative biological effectiveness [RBE]) in 10 fractions, completing a minimum follow-up of 36 months. Rib fractures were detected by follow-up chest computed tomography (CT) examination, independent of symptoms of thoracic pain. Dose-volume histograms of separately contoured ribs on planning CT images were calculated by the treatment planning system in a retrospective manner. Kaplan-Meier and Cox proportional hazards analyses were performed on individual ribs to identify significant risk factors associated with RIRF.

RESULTS

Among the 85 patients finally involved in this study, we identified 116 fractured ribs in 55 participants (64.7%). The 2- and 3-year frequencies of experiencing any RIRF were 36.5% and 52.9%, respectively. The median time-to-fracture was 23.5 months (range: 5-65). We used a total of 224 ribs irradiated over 50 Gy (RBE)-including all the detected fractured ribs-for statistical analysis. Univariate and multivariate analyses revealed the maximum-rib dose to a small volume, position of the maximum-dose point, bone mineral density, 1st rib number, and use of systemic corticosteroids to be related to the incidence of RIRFs.

CONCLUSIONS

In addition to dosimetric parameters, factors related to skeletal structure and bone strength are crucial predictors of proton RIRFs and should be considered for safer radiation therapy.

Investigation of factors related to treatment planning of x-ray SBRT and scanning carbon-ion radiation therapy for early-stage lung cancer patients

This study aimed to compare the treatment plans of x-ray SBRT and scanning carbon ion radiation therapy (CIRT) for localized lung tumors, and to evaluate the dose dependence of tumor size tumor-to-heart distance. For phantom verification, we used a chest phantom with a spherical simulated tumor. Treatment plans for 3-dimensional conformal radiation therapy (3D-CRT), volumetric modulated arc therapy (VMAT), and CIRT were created. GTVs were created in sizes ranging from 0.5 to 5 cm in diameter, and the dependence of the lung dose on GTV diameter was evaluated for each treatment plan. For patient validation, 30 cases of localized lung tumors were analyzed. 3D-CRT, VMAT, and CIRT treatment plans were developed, and DVH parameters were evaluated for each GTV size and GTV-to-heart distance. In both phantom and patient validations, the OAR doses were the lowest for CIRT. The lung dose increased with increasing GTV diameter for all three treatment plans. CIRT had the smallest ratio of lung dose increase to GTV diameter increase among the three treatment plans. Heart dose in CIRT was independent of GTV size and GTV-to-heart distance Conclusions: The results of the present study suggested that the use of scanning CIRT can reduce the OAR dose while guaranteeing the tumor dose compared to x-ray SBRT. In addition, it was suggested that CIRT can treat patients with large GTV sizes while maintaining low lung and heart dose.

Chronic progressive pulmonary aspergillosis within the irradiated field after stereotactic body radiotherapy: two case reports

Stereotactic body radiation therapy (SBRT) is the standard treatment for patients who are medically inoperable or who refuse surgery with stage I non-small cell lung cancer (NSCLC). While acute lymphopenia following SBRT is documented, the long-term effects on the immune system and infectious disease remain unclear. In this report, we present two cases of chronic progressive pulmonary aspergillosis (CPPA) occurring within the irradiated field following SBRT for inoperable stage I NSCLC. Case 1 was a man in his 70 s with a history of smoking and a previous pulmonary resection and SBRT for metachronous primary lung cancer. He received SBRT for T1aN0M0 NSCLC in the right lower lobe as his third primary lung cancer. After 20 months, the patient developed a cough and sputum, and a computed tomography (CT) scan revealed a cavity shadow in the irradiated field, which led to the diagnosis of CPPA. Intravenous voriconazole was immediately started, and after 3 week's administration, the symptoms improved, and the cavity disappeared. After 34 months, the patient died with no recurrence of CPPA and lung cancer. Case 2 was a man in his 80 s with a history of smoking and previous pulmonary resection for lung cancer. He received SBRT for T1cN0M0 NSCLC in the right lower lobe as his second primary lung cancer. After 19 months, the patient developed a fever, and a CT scan revealed a cavity shadow in the irradiated field, which led to the diagnosis of CPPA. Oral itraconazole was administered, followed by diarrhea and anorexia. After 22 days, the patient died. During the follow-up period, there was no recurrence of lung cancer. Risk factors for CPPA include a history of smoking and lung resection, common among candidates for pulmonary SBRT. When a cavity shadow develops following SBRT, differentiating consolidation as radiation pneumonitis, local recurrence, or infection can be challenging. When a cavity is identified on a follow-up CT scan after SBRT, it is crucial to include CPPA in the differential diagnosis.

Effect of Treatment Delivery Schedule for Patients With Early-Stage Non-Small Cell Lung Cancer Treated With Stereotactic Ablative Radiation Therapy: A Population-Based Analysis

PURPOSE

The optimal SABR treatment delivery schedule in stage I non-small cell lung cancer (NSCLC) remains unclear. This population-based study investigated grade ≥2 toxicity rates, local failure (LF), and overall survival (OS) in patients treated with 48 Gy in 4 fractions scheduled every other day versus daily with weekends and consecutive daily without weekends.

METHODS AND MATERIALS

Between January 2019 and June 2022, treatment records using 48 Gy in 4 fractions were extracted from a provincial cancer registry and grouped by delivery as every other day, daily with weekends, or consecutive daily without weekends. Toxicity events were recorded using National Cancer Institute Common Terminology Criteria for Adverse Events, version 5.0. The Kaplan-Meier method was used to compute OS and LF was calculated using cumulative incidence methods with death as a competing risk. Cox regression analyses and Fine-Gray modeling was used to assess for variables associated with OS and LF, respectively.

RESULTS

Of 404 patients meeting study criteria, 190, 111, and 103 received SABR every other day, daily with weekends, and consecutive daily without weekends, respectively. More patients receiving SABR daily with weekends were medically inoperable and more patients receiving SABR consecutive daily without weekends had tumors abutting the chest wall. Median follow-up time was 29.5 months (IQR, 19.2-38.4 months). Overall toxicity was low, with crude rates of acute and late grade ≥2 toxicity not being statistically different among the groups. No grade 4 or 5 toxicities were recorded. LF rates at 24 months were not different at 7.5% (95% CI, 3.7-11.3), 9.5% (95% CI, 3.9-15.1), and 11.0% (95% CI, 4.9-17.2) for the every other day, daily with weekends, and consecutive daily without weekends groups, respectively (P = .60). Schedules of daily with weekends and consecutive daily without weekends were not associated with LF. Similarly, no significant differences in median OS were found among the every other day, daily with weekends, and consecutive daily without weekends groups at 47.5 months (95% CI, 39.26-55.74), 52.7 months (95% CI, 34.7-70.7), and 49.0 months (95% CI, 31.6-66.4), respectively. Schedules of daily with weekends and consecutive daily without weekends were not associated with OS.

CONCLUSIONS

This population-based study demonstrated no statistically significant differences in grade ≥2 toxicity rates, LF, and OS for patients with stage I NSCLC treated with lung SABR using 48 Gy in 4 fractions delivered every other day, daily with weekends, and consecutive daily without weekends. Patient convenience and optimization of resources may be considered when choosing a lung SABR treatment delivery schedule.

[Stereotactic radiotherapy for lung cancer]

The treatment of early stage T1-T2N0M0 non-small cell lung cancers (NSCLC) was previously based on surgery. However, 20 to 25% of patients are inoperable due to their age, comorbidities or refuse surgery. Since 2018, stereotactic body radiation therapy (SBRT) has become the standard treatment for these patients. For operable patients, the comparison surgery - SBRT is difficult without a clear conclusion, the different phase III trials have not yet permitted to provide a formal answer in terms of local control and survival by default of inclusion. Dose and fractionation need to be selected according to tumor location. Tolerance is usually good, with few grade ≥3 toxicities; however, caution is advised for ultra-central tumors and in case of interstitial pneumonia. Post-therapeutic imaging monitoring is complex, sometimes with uncertainties between radiation-induced pneumonitis and relapse. This complexity may increase in ongoing trials combining SBRT and immunotherapy.

Recent developments in the field of radiotherapy for the management of lung cancer

Lung cancer has a poor prognosis, and further improvements in outcomes are needed. Radiotherapy plays an important role in the treatment of unresectable lung cancer, and there have been recent developments in the field of radiotherapy for the management of lung cancer. However, to date, there have been few reviews on the improvement in treatment outcomes associated with high precision radiotherapy for lung cancer. Thus, this review aimed to summarize the recent developments in radiotherapy techniques and indicate the future directions in the use of radiotherapy for lung cancer. Stereotactic body radiotherapy (SBRT) for unresectable stage I lung cancer has been reported to improve local control rates without severe adverse events, such as radiation pneumonitis. For locally advanced lung cancer, a combination of chemoradiotherapy and adjuvant immune checkpoint inhibitors dramatically improves treatment outcomes, and intensity-modulated radiotherapy (IMRT) enables safer radiation therapy with less frequent pneumonitis. Particle beam therapy, such as carbon-ion radiotherapy and proton beam therapy, has been administered as advanced medical care for patients with lung cancer. Since 2024, it has been covered under insurance for early stage lung cancer with tumors ≤ 5 cm in size in Japan. In addition to chemotherapy, local ablative radiotherapy improves treatment outcomes in patients with oligometastatic stage IV lung cancer. A particular problem with radiotherapy for lung cancer is that the target location changes with respiratory motion, and various physical methods have been used to control respiratory motion. Recently, coronavirus disease has had a major impact on lung cancer treatment, and cancer treatment during situations, such as the coronavirus pandemic, must be performed carefully. To improve treatment outcomes for lung cancer, it is necessary to fully utilize evolving radiotherapy modalities, and the role of radiotherapy in lung cancer treatment is expected to increase.

Salvage surgery and conversion surgery for patients with nonsmall cell lung cancer: a narrative review

Nonsmall cell lung cancer (NSCLC) remains the leading cause of cancer-related deaths. With the development of screening, patient selection, and treatment strategies, patients' survival outcomes and living quality significantly improved. However, some patients still have local recurrence or residual tumors after receiving definitive therapies. Salvage surgery has been regarded as an effective option for recurrent or residual NSCLC, but its effectiveness remains undetermined. Furthermore, conversion surgery is a special type of salvage surgery for tumors converted from 'initially unresectable' to 'potentially resectable' status due to a favorable response to systemic treatments. Although conversion surgery is a promising curative procedure for advanced NSCLC, its concept and clinical value remain unfamiliar to clinicians. In this narrative review, we provided an overview of the safety and efficacy of salvage surgery, especially salvage surgery after sublobar resection in early-stage NSCLC. More importantly, we highlighted the concept and value of conversion surgery after systemic treatment in advanced NSCLC to gain some insights into its role in the treatment of lung cancer.

High barriers to treatment are associated with stereotactic radiation instead of surgery for patients with operable stage I non-small cell lung cancer†

OBJECTIVES

Although surgery is considered the standard of care for early-stage lung cancer, there has been increased use of stereotactic radiotherapy for operable patients in recent years. Given that this modality may be perceived as a more practical treatment, we hypothesized that it might be more often delivered to patients who experience barriers to care.

METHODS

The National Cancer Database (2018-2020) was queried for patients with clinical stage IA non-small cell lung cancer treated with surgery or stereotactic radiotherapy (48-60 Gy, 3-5 fractions), excluding patients with contraindications to surgery. Patients who had all the following characteristics were categorized as experiencing 'high barriers' to treatment: income below median national levels, lack of private insurance, treatment at a community facility and residence in non-metropolitan areas. Using multivariable logistic regression, the association between high barriers to treatment and stereotactic radiotherapy use was estimated.

RESULTS

A total of 60 829 patients were included, of whom 3382 (5.6%) experienced high barriers to treatment. Among them, 13 535 (22.3%) underwent stereotactic radiotherapy and 47 294 (77.7%) underwent surgery. Overall, more patients undergoing stereotactic radiotherapy faced high barriers to treatment compared to those who received surgery (8.6% vs 4.7%, P < 0.001). Geographic region was associated with the delivery of stereotactic radiotherapy (P < 0.001). The magnitude of such association was stronger among those who faced high barriers. In multivariable analysis, experiencing high barriers to treatment remained associated with receiving stereotactic radiotherapy (OR: 1.46, 95% CI 1.35-1.58).

CONCLUSIONS

The use of stereotactic radiotherapy is more prevalent among patients facing barriers to care. Further research is needed to clarify the role of this treatment modality in early-stage lung cancer.

Systematic Review of Stereotactic Ablative Radiotherapy (SABR)/Stereotactic Body Radiation Therapy (SBRT) for Treatment of High-Risk Patients with Stage I Non-Small Cell Lung Cancer

Stereotactic ablative radiotherapy (SABR) has emerged as an alternative, non-surgical treatment for high-risk patients with stage I non-small cell lung cancer (NSCLC) with increased use over time. The American Association for Thoracic Surgery (AATS) Clinical Practice Standards Committee (CPSC) assembled an expert panel and conducted a systematic review of the literature evaluating the results of SABR, which is also referred to as stereotactic body radiation therapy (SBRT) or stereotactic radiosurgery (SRS), prior to developing treatment recommendations for high-risk patients with stage I NSCLC based on expert consensus. Publications detailing the findings of 16 prospective studies of SABR and 14 retrospective studies of SABR for the management of early-stage lung cancer in 54,697 patients were identified by systematic review of the literature with further review by members of our expert panel. Medical inoperability (93-95%) was the primary reason for utilizing SABR. The median rate of histologically confirmed cancer in treated patients was 67% (range 57-86%). In retrospective studies and prospective studies, the most common dosing regimens were 48-54Gy in 3-5 fractions and 44-66Gy in 3-5 fractions respectively. The median follow-up after SABR was 30 months (range 15-50). The complications, oncological results and quality of life after SABR in high-risk patients with early-stage NSCLC are summarized in this Expert Review article. Further prospective randomized trials are needed and are currently underway to compare outcomes after SABR with outcomes after sublobar resection to fully evaluate treatment options applicable this high-risk group of patients.

Stereotactic ablative radiotherapy (SABR) for patients with lung tumor and severe pulmonary function impairment

PURPOSE

To evaluate clinical outcomes after SABR in a cohort of early-stage non-small cell lung cancer (NSCLC) or pulmonary metastases in chronic obstructive pulmonary disease (COPD) patients with forced expiratory volume in the first second predicted (FEV1) ≤ 50%.

METHODS

Retrospective single-center study was performed to analyze clinical outcomes and toxicities in COPD patients with severe lung dysfunction treated with SABR from 1st June 2015 to 31st October 2022.

RESULTS

Thirty four patients (forty locations) were enrolled for analysis. Median follow-up was 2.9 years. Median age was 73.5 years (range, 65.6-80.1). FEV1 was 38% (range, 28.2-50.0) prior to radiotherapy. Median overall survival (OS) was 41.1 months (95% CI 38.9-not reached). OS rates at 2-, 3-, and 5- years were 79%, 71%, and 36%, respectively. Cancer-specific survival rates at 2-, 3-, and 5- years were 96%, 96%, and 68%, respectively. Local control rates at 2-, 3-, and 5- years were 88%, 83%, and 83%, respectively. No grade 4 or 5 toxicity was observed. The most common acute toxicity was pneumonitis (38.2%), of which only 1 patient (2.9%) reported grade 3 acute toxicity.

CONCLUSIONS

Lung SABR in patients with poor pulmonary function may be effective with acceptable toxicity.

Effect of patient and tumor characteristics on respiratory motion in early-stage peripheral lung cancer (Tis ~ T2bN0M0) treated with stereotactic body radiation therapy (SBRT)

Background

Recent advances in stereotactic body radiation therapy (SBRT) technology for early-stage peripheral lung cancer have been remarkable and are becoming a viable alternative to surgery. However, the most important problem in performing SBRT correctly is minimizing the respiratory motion of the tumor.

Materials and methods

Thirty-eight patients treated with SBRT were evaluated to clarify factors affecting respiratory motion of early-stage peripheral lung cancer in the management of restrictive breathing technique (abdominal compression) to reduce respiratory tumor motion in SBRT. We investigated age, gender, body mass index (BMI), Brinkman index (BI), forced expiratory volume in 1 second (FEV 1.0), and type of ventilatory impairment as patient factors, and T-factor, stage, tumor-bearing lung lobe, and tumor pathology as tumor factors. Respiratory motion was assessed by volume differences between clinical target volume (CTV) and internal target volume (ITV). The degree of tumor motion due to respiration was compared using the formula of (ITV-CTV)/CTV as an index.

Results

In the results, univariate analyses showed that only age was a significant predictor of respiratory tumor motion (p = 0.048). In multi-variate analyses, only T factor was an independent significant predictor of respiratory tumor motion (p = 0.045), while there was a significant trend for age (p = 0.061), and tumor location (p = 0.067).

Conclusions

In late elderly patients or T1a tumor, respiratory motion in early-stage peripheral lung cancer was significantly large. However, it is not predictable by patient and tumor characteristics. Therefore, respiratory motion of the tumor should be measured in all patients in some way.

Prospective external validation of radiomics-based predictive model of distant metastasis after dynamic tumor tracking stereotactic body radiation therapy in patients with non-small-cell lung cancer: A multi-institutional analysis

BACKGROUND AND PURPOSE

This study aims to externally validate a predictive model for distant metastasis (DM) with computed tomography (CT)-based radiomics features in prospectively enrolled non-small-cell lung cancer patients undergoing dynamic tumor-tracking stereotactic body radiation therapy (DTT-SBRT).

MATERIALS AND METHODS

The study collected retrospective data from 567 patients across 11 institutions as the training dataset and prospectively enrolled 42 patients from four institutions as the external test dataset. Four clinical features were collected, and 944 CT-based radiomic features were extracted from gross tumor volumes. After standardization and feature selection, DM predictive models were developed using fine and gray regression (FG) and random survival forest (RSF), incorporating clinical and radiomic features, and their combinations within the training dataset. Then, the model was applied to the test dataset, dividing patients into high- and low-risk groups based on medians of risk scores. Model performance was assessed using the concordance index (C-index), and the statistical significance between groups was evaluated using Gray's test.

RESULTS

In the training dataset, 122 of 567 patients (21.5%) developed DM, compared to 9 of 42 patients (21.4%) in the test dataset. In the test dataset, the C-indices of the clinical, radiomics, and hybrid models with FG were 0.559, 0.544, and 0.560, respectively, whereas those with RSF were 0.576, 0.604, and 0.627, respectively. The hybrid model with RSF, which exhibited the best predictive performance of all models, identified 7 of 23 patients (30.4%) as high risk and 2 of 19 patients (10.5%) as low risk for DM incidence in the test dataset (p = 0.116).

CONCLUSION

Although predictive models for DM lack significance when applied to prospectively enrolled cases undergoing DTT-lung SBRT, the model with RSF exhibits a consistent capacity to effectively classify patients at a high risk of developing DM.

Proton and carbon ion radiotherapy for operable early-stage lung cancer; a prospective nationwide registry

BACKGROUND AND PURPOSE

To investigate the toxicity and survival outcomes of proton and carbon ion radiotherapy for patients with operable early-stage lung cancer who are eligible for lobectomy.

MATERIALS AND METHODS

This multicenter nationwide prospective cohort study included patients with operable early-stage lung cancer. Proton and carbon ion radiotherapy was performed according to the schedule stipulated in the unified treatment policy. Progression-free survival (PFS), overall survival (OS) and treatment-related toxicities were evaluated.

RESULTS

A total of 274 patients were enrolled and included in efficacy and safety analyses. The most common tumor type was adenocarcinoma (44 %), while 105 cases (38 %) were not histologically confirmed or diagnosed clinically. Overall, 250 (91 %) of the 274 patients had tumors that were peripherally situated, while 138 (50 %) and 136 (50 %) patients were treated by proton and carbon ion radiotherapy, respectively. The median follow-up time for all censored patients was 42.8 months (IQR 36.7-49.0). Grade 3 or severe treatment-related toxicity was observed in 4 cases (1.5 %). Three-year PFS was 80.5 % (95 % CI: 75.7 %-85.5 %) and OS was 92.5 % (95 % CI: 89.3 %-95.8 %). Pathological confirmation and clinical stage were factors significantly associated with PFS, while tumor location and particle-ion type were not. Meanwhile, clinical stage was significantly associated with OS, but pathological confirmation, tumor location, and particle-ion type were not.

CONCLUSIONS

Particle therapy for operable early-stage lung cancer resulted in excellent 3-year OS and PFS in each subset. In this disease context, proton and carbon ion beam therapies are feasible alternatives to curative surgery.

Potential Role of Lymphocyte CD44 in Determining Treatment Selection Between Stereotactic Body Radiation Therapy and Surgery for Early-Stage Non-Small Cell Lung Cancer

PURPOSE

Stereotactic body radiation therapy (SBRT) versus surgery for operable early-stage non-small cell lung cancer (ES-NSCLC) remains highly debated. Herein, we used spatial proteomics to identify whether any molecular biomarker(s) associate with the efficacy of either modality, in efforts to optimize treatment selection between surgery and SBRT for this population.

METHODS AND MATERIALS

We evaluated biopsy tissue samples from 44 patients with ES-NSCLC treated with first-line SBRT (cohort 1) by GeoMx Digital Spatial Profiling (DSP) with a panel of 70 proteins in 5 spatial molecular compartments: tumor (panCK+), leukocyte (CD45+), lymphocyte (CD3+), macrophage (CD68+), and stroma (α-SMA+). To validate the findings in cohort 1, biopsy samples from 52 patients with ES-NSCLC who received SBRT (cohort 2) and 62 patients with ES-NSCLC who underwent surgery (cohort 3) were collected and analyzed by multiplex immunofluorescence (mIF).

RESULTS

In cohort 1, higher CD44 expression in the lymphocyte compartment was associated with poorer recurrence-free survival (RFS) (DSP: P < .001; mIF: P < .001) and higher recurrence rate (DSP: P = .001; mIF: P = .004). mIF data from cohort 2 validated these findings (P < .05 for all). From cohort 3, higher lymphocyte CD44 predicted higher RFS after surgery (P = .003). Intermodality comparisons demonstrated that SBRT was associated with significantly higher RFS over surgery in CD44-low patients (P < .001), but surgery was superior to SBRT in CD44-high cases (P = .016).

CONCLUSIONS

Lymphocyte CD44 may not only be a predictor of SBRT efficacy in this population but also an important biomarker (pending validation by large prospective data) that could better sharpen selection for SBRT versus surgery in ES-NSCLC.

Quantitative analysis of interstitial lung abnormalities on computed tomography to predict symptomatic radiation pneumonitis after lung stereotactic body radiotherapy

BACKGROUND AND PURPOSE

Symptomatic radiation pneumonitis (SRP) is a complication of thoracic stereotactic body radiotherapy (SBRT). As visual assessments pose limitations, artificial intelligence-based quantitative computed tomography image analysis software (AIQCT) may help predict SRP risk. We aimed to evaluate high-resolution computed tomography (HRCT) images with AIQCT to develop a predictive model for SRP.

MATERIALS AND METHODS

AIQCT automatically labelled HRCT images of patients treated with SBRT for stage I lung cancer according to lung parenchymal pattern. Quantitative data including the volume and mean dose (Dmean) were obtained for reticulation + honeycombing (Ret + HC), consolidation + ground-glass opacities, bronchi (Br), and normal lungs (NL). After associations between AIQCT's quantified metrics and SRP were investigated, we developed a predictive model using recursive partitioning analysis (RPA) for the training cohort and assessed its reproducibility with the testing cohort.

RESULTS

Overall, 26 of 207 patients developed SRP. There were significant between-group differences in the Ret + HC, Br-volume, and NL-Dmean in patients with and without SRP. RPA identified the following risk groups: NL-Dmean ≥ 6.6 Gy (high-risk, n = 8), NL-Dmean < 6.6 Gy and Br-volume ≥ 2.5 % (intermediate-risk, n = 13), and NL-Dmean < 6.6 Gy and Br-volume < 2.5 % (low-risk, n = 133). The incidences of SRP in these groups within the training cohort were 62.5, 38.4, and 7.5 %; and in the testing cohort 50.0, 27.3, and 5.0 %, respectively.

CONCLUSION

AIQCT identified CT features associated with SRP. A predictive model for SRP was proposed based on AI-detected Br-volume and the NL-Dmean.

The effect of increasing the prescribed dose in stereotactic body radiotherapy for primary lung cancer without lymph node metastasis

BACKGROUND

This study aimed to identify the efficacy of increasing the dose of stereotactic body radiotherapy (SBRT) for lung cancer.

METHOD AND MATERIALS

Patients who received SBRT for primary lung cancer between 2002 and 2021 were evaluated retrospectively. The patients were categorized into the 48, 50, and 55 Gy groups according to the prescribed dose. Analyses were performed for all matched patients.

RESULT

A total of 323 patients underwent SBRT for lung lesions at doses of 48, 50, and 55 Gy in four fractions. The median follow-up period in the 55 Gy group (32.3 months; Interquartile range (IQR), 15.1-54.1 months, P = 0.01) was significantly shorter than in the 48 Gy (47.0 months; IQR, 16,2-107.7 months) and 50 Gy (78.9 months; IQR 47.2-104.2 months) groups. The 3-year local progression-free survival (LPFS) was 90% in the 55 Gy group (95% confidence interval (CI), 62.4%-94.0%), 75.7% in the 48 Gy group (62.1%-85.0%), and 79.1% in the 50 Gy group (62.2%-89.1%). LPFS in the 55 Gy group was significantly higher than that in the 48 Gy group (hazard ratio (HR), 0.40; 95% CI, 0.20-0.79; P = 0.025). There is no significant difference in the local control rate between the 55 Gy group and the 50 Gy group (HR 0.60, CI 0.27-1.39). After propensity score matching, the 3-year LPFS in the 55 Gy group was 88.3% (CI, 71.2-95.5%). LPFS in the 55 Gy group did not significantly differ from that of the 48 Gy group (HR, 0.47; CI, 0.17-1.35) and the 50 Gy group (HR, 0.83; CI, 0.28-2.51).

CONCLUSION

We conducted the analysis using propensity score matching. It was not apparent whether there was a significant difference in the effect of increasing the dose, owing to a lack of power caused by the small number of cases after propensity score matching. A prospective study is in progress, and the results are awaited.

Long-term survival outcomes and quality of life of image-guided proton therapy for operable stage I non-small cell lung cancer: A phase 2 study

BACKGROUND AND PURPOSE

This study evaluated long-term efficacy, safety, and changes in quality of life (QOL) of patients after image-guided proton therapy (IGPT) for operable stage I non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

This single-institutional prospective phase 2 study enrolled patients with operable histologically confirmed stage IA or IB NSCLC (7th edition of UICC). The prescribed dose was 66 Gy relative biological effectiveness equivalents (GyRBE) in 10 fractions for peripheral lesions, or 72.6 GyRBE in 22 fractions for central lesions. The primary endpoint was the 3-year overall survival (OS). The secondary endpoints included disease control, toxicity, and changes in QOL score.

RESULTS

We enrolled 43 patients (median age: 68 years; range, 47-79 years) between July 2013 to January 2021, of whom 41 (95 %) had peripheral lesions and 27 (63 %) were stage IA. OS, local control, and progression-free survival rates were 95 % (95 % CI: 83-99), 95 % (82-99), and 86 % (72-94), respectively, at 3 years, and 83 % (66-92), 95 % (82-99), and 77 % (60-88), respectively, at 7 years. Four patients (9 %) developed grade 2, and one patient (2 %) developed grade 3 radiation pneumonitis. No other grade 3 or higher adverse events were observed. In the QOL analysis, global QOL remained favorable; however, approximately 40 % of patients reported dyspnea at 3 and 24 months.

CONCLUSION

Our findings suggest that IGPT provides effective disease control and survival in operable stage I NSCLC, particularly for peripheral lesions. Moreover, toxicity associated with IGPT was minimal, and patients reported favorable QOL.

Histology-driven hypofractionated radiation therapy schemes for early-stage lung adenocarcinoma and squamous cell carcinoma

BACKGROUND AND PURPOSE

Histology was found to be an important prognostic factor for local tumor control probability (TCP) after stereotactic body radiotherapy (SBRT) of early-stage non-small-cell lung cancer (NSCLC). A histology-driven SBRT approach has not been explored in routine clinical practice and histology-dependent fractionation schemes remain unknown. Here, we analyzed pooled histologic TCP data as a function of biologically effective dose (BED) to determine histology-driven fractionation schemes for SBRT and hypofractionated radiotherapy of two predominant early-stage NSCLC histologic subtypes adenocarcinoma (ADC) and squamous cell carcinoma (SCC).

MATERIAL AND METHODS

The least-χ2 method was used to fit the collected histologic TCP data of 8510 early-stage NSCLC patients to determine parameters for a well-developed radiobiological model per the Hypofractionated Treatment Effects in the Clinic (HyTEC) initiative.

RESULTS

A fit to the histologic TCP data yielded independent radiobiological parameter sets for radiotherapy of early-stage lung ADC and SCC. TCP increases steeply with BED and reaches an asymptotic maximal plateau, allowing us to determine model-independent optimal fractionation schemes of least doses in 1-30 fractions to achieve maximal tumor control for early-stage lung ADC and SCC, e.g., 30, 44, 48, and 51 Gy for ADC, and 32, 48, 54, and 58 Gy for SCC in 1, 3, 4, and 5 fractions, respectively.

CONCLUSION

We presented the first determination of histology-dependent radiobiological parameters and model-independent histology-driven optimal SBRT and hypofractionated radiation therapy schemes for early-stage lung ADC and SCC. SCC requires substantially higher radiation doses to maximize tumor control than ADC, plausibly attributed to tumor genetic diversity and microenvironment. The determined optimal SBRT schemes agree well with clinical practice for early-stage lung ADC. These proposed optimal fractionation schemes provide first insights for histology-based personalized radiotherapy of two predominant early-stage NSCLC subtypes ADC and SCC, which require further validation with large-scale histologic TCP data.

Intra- and inter-fractional variations of tumors with fiducial markers measured using respiratory-correlated computed tomography images for respiratory gated lung stereotactic body radiation therapy

PURPOSE

This study evaluated the intra- and inter-fractional variation of tumors with fiducial markers (FMs), relative to the tumor-FM distance, to establish how close an FM should be inserted for respiratory-gated stereotactic body radiation therapy (RG-SBRT).

METHODS

Forty-five lung tumors treated with RG-SBRT were enrolled. End-expiratory computed tomography (CT) (CTplan) and four-dimensional-CT (4D-CT) scans were obtained for planning. End-expiratory CT (CTfr) scanning was performed before each fraction. The FMs were divided into two groups based on the median tumor-FM distance in the CTplan (Dp). For the intra-fractional variation, the correlations between the corresponding tumor and FM intra-fractional motions, defined as the centroid coordinates of those in each 0-90% phase, with the 50% phase of 4D-CT as the origin, were calculated in the left-right, anterior-posterior, and superior-inferior directions. Furthermore, the maximum difference in the tumor-FM distance in each phase of 4D-CT scan, based on those in the 50% phase of 4D-CT scan (Dmax), was obtained. Inter-fractional variation was defined as the maximum distance between the tumors in CTplan and CTfr, when the CT scans were fused based on each FM or vertebra.

RESULTS

The median Dp was 26.1 mm. While FM intra-fractional motions were significantly and strongly correlated with the tumor intra-fractional motions in only anterior-posterior and superior-inferior directions for the Dp > 26 mm group, they were significantly and strongly correlated in all directions for the Dp ≤ 26 mm group. In all directions, Dmax values of the Dp ≤ 26 mm group were lower than those of the Dp > 26 mm group. The inter-fractional variations based on the Dp ≤ 26 mm were smaller than those on the Dp > 26 mm and on the vertebra in all directions.

CONCLUSIONS

Regarding intra- and inter-fractional variation, FMs for Dp ≤ 26 mm can increase the accuracy for RG-SBRT.

Dosimetric evaluation in Helical TomoTherapy for lung SBRT using Monte Carlo-based independent dose verification software

PURPOSE

To elucidate the dosimetric errors caused by a model-based algorithm in lung stereotactic body radiation therapy (SBRT) with Helical TomoTherapy (HT) using Monte Carlo (MC)-based dose verification software.

METHODS

For 38 plans of lung SBRT, the dose calculation accuracy of a treatment planning system (TPS) of HT was compared with the results of DoseCHECK, the commercial MC-based independent verification software. The following indices were extracted to evaluate the correlation of dosimetric errors: (1) target volume, (2) average computed tomography (CT) value of the planning target volume (PTV) margin, and (3) average CT value of surrounding 2-mm area of the PTV (PTV ring). Receiver operating characteristic (ROC) analyses determined the threshold for 5% of differences in PTV D95%. Then, the 38 plans were classified into two groups using the cutoff values of ROC analysis for these three indices. Dosimetric differences between groups were statistically compared using the Mann-Whitney U test.

RESULTS

TPS of HT overestimated by more than 5% in the PTV D95% in 16 of 38 plans. The PTV ring showed the strongest correlation with dosimetric differences. The cutoff value for the target volume, the PTV margin, and the PTV ring was 14.7 cc, -754 HU, and -708 HU, respectively. The area under the curve (AUC) for the target volume, the PTV margin, and the PTV ring were 0.835, 0.878, and 0.932, respectively. Dosimetric errors more than 5% were observed when the PTV volume was less than 15 cc or when the CT value around the target was less than -700 HU.

CONCLUSION

The TPS of HT might overestimate the PTV dose by more than 5% if any the three indices in this study were below threshold. Therefore, independent verification with an MC-based algorithm should be strongly recommended for lung SBRT in HT.

Impact of Maximum Point Dose Within the Planning Target Volume on Local Control of Nonsmall Cell Lung Cancer Treated With Stereotactic Body Radiotherapy

BACKGROUND

No consensus exists on the maximum dose delivered to the planning target volume (PTV) in the delivery of stereotactic body radiotherapy (SBRT) for primary lung cancer. We investigated whether higher biologically effective doses (BED) within the PTV were associated with improved tumor control.

METHODS

We reviewed patients with early-stage, node-negative nonsmall cell lung cancer who received curative-intent SBRT between 2005 and 2018. We calculated the maximum BED (maxBED) within the PTV for all patients, analyzing outcomes using the cumulative incidence method and Fine-Gray test statistics to assess prognostic impact.

RESULTS

We analyzed 171 patients (median age, 70.2; range, 43 to 90 y) with 181 lung nodules. Median follow-up was 2.7 years (range, 0.1 to 12 y) for all patients and 4.2 years (range, 0.2 to 8.4 y) for living patients. Median maximum tumor diameter was 1.9 cm (range, 0.7 to 5.6 cm). Patients received a prescription of 48 or 50 Gy in 4 or 5 fractions, respectively, except for one who received 60 Gy in 5 fractions. Median maxBED was 120 Gy (range, 101 to 171 Gy). There was no difference in the 3-year local control (LC) rate among patients treated with a maxBED<120 Gy versus ≥120 Gy ( P =0.83).

CONCLUSIONS

No significant differences in LC were observed between patients with early-stage nonsmall cell lung cancer treated with SBRT in 4 or 5 fractions with a maxBED≥120 Gy. However, a higher maxBED trended toward improved LC rates, suggesting a maxBED threshold greater than 120 Gy may be needed to improve LC rates.

Protocol of a phase II study to evaluate the efficacy and safety of deep-inspiration breath-hold daily online adaptive radiotherapy for centrally located lung tumours (PUDDING study)

BACKGROUND

Centrally located lung tumours present a challenge because of their tendency to exhibit symptoms such as airway obstruction, atelectasis, and bleeding. Surgical resection of these tumours often requires sacrificing the lungs, making definitive radiotherapy the preferred alternative to avoid pneumonectomy. However, the proximity of these tumours to mediastinal organs at risk increases the potential for severe adverse events. To mitigate this risk, we propose a dual-method approach: deep inspiration breath-hold (DIBH) radiotherapy combined with adaptive radiotherapy. The aim of this single-centre, single-arm phase II study is to investigate the efficacy and safety of DIBH daily online adaptive radiotherapy.

METHODS

Patients diagnosed with centrally located lung tumours according to the International Association for the Study of Lung Cancer recommendations, are enrolled and subjected to DIBH daily online adaptive radiotherapy. The primary endpoint is the one-year cumulative incidence of grade 3 or more severe adverse events, as classified by the Common Terminology Criteria for Adverse Events (CTCAE v5.0).

DISCUSSION

Delivering definitive radiotherapy for centrally located lung tumours presents a dilemma between ensuring optimal dose coverage for the planning target volume and the associated increased risk of adverse events. DIBH provides measurable dosimetric benefits by increasing the normal lung volume and distancing the tumour from critical mediastinal organs at risk, leading to reduced toxicity. DIBH adaptive radiotherapy has been proposed as an adjunct treatment option for abdominal and pelvic cancers. If the application of DIBH adaptive radiotherapy to centrally located lung tumours proves successful, this approach could shape future phase III trials and offer novel perspectives in lung tumour radiotherapy.

TRIAL REGISTRATION

Registered at the Japan Registry of Clinical Trials (jRCT; https://jrct.niph.go.jp/ ); registration number: jRCT1052230085 ( https://jrct.niph.go.jp/en-latest-detail/jRCT1052230085 ).

Factors associated with cavity formation after stereotactic body radiation therapy for peripheral early-stage lung cancer

PURPOSE

This retrospective study aimed to identify the factors associated with cavity formation after SBRT in peripheral early-stage lung cancer patients. We analyzed the occurrence of cavity changes after SBRT.

MATERIALS AND METHODS

We examined 99 cases with T1-T2aN0 peripheral non-small cell lung cancer treated with SBRT from 2004 to 2021. Patients underwent respiratory function tests, including diffusing capacity for carbon monoxide (DLco), before treatment. The median observation period was 35 months (IQR 18-47.5 months). Treatment involved fixed multi-portal irradiation in 67% of cases and VMAT in 33%. The total radiation doses ranged from 42 to 55 Gy, delivered over 4 to 5 fractions.

RESULTS

Cavity formation occurred in 14 cases (14.1%), appearing a median of 8 months after SBRT. The cavity disappeared in a median of 4 months after formation. High DLco and total radiation dose were identified as factors significantly associated with cavity formation. There have been no confirmed recurrences to date, but one patient developed a lung abscess.

CONCLUSION

Although cavity formation after SBRT for peripheral early-stage lung cancer is infrequent, it can occur. This study showed high DLco and total radiation dose to be factors significantly associated with cavity formation. These findings can be applied to optimizing radiation therapy (RT) and improving patient outcomes. Further research is needed to determine the optimal radiation dose for patients with near-normal DLco for whom surgery is an option. This study provides valuable insights into image changes after RT.

Multicentric development and evaluation of [18F]FDG PET/CT and CT radiomic models to predict regional and/or distant recurrence in early-stage non-small cell lung cancer treated by stereotactic body radiation therapy

PURPOSE

To develop machine learning models to predict regional and/or distant recurrence in patients with early-stage non-small cell lung cancer (ES-NSCLC) after stereotactic body radiation therapy (SBRT) using [18F]FDG PET/CT and CT radiomics combined with clinical and dosimetric parameters.

METHODS

We retrospectively collected 464 patients (60% for training and 40% for testing) from University Hospital of Liège and 63 patients from University Hospital of Brest (external testing set) with ES-NSCLC treated with SBRT between 2010 and 2020 and who had undergone pretreatment [18F]FDG PET/CT and planning CT. Radiomic features were extracted using the PyRadiomics toolbox®. The ComBat harmonization method was applied to reduce the batch effect between centers. Clinical, radiomic, and combined models were trained and tested using a neural network approach to predict regional and/or distant recurrence.

RESULTS

In the training (n = 273) and testing sets (n = 191 and n = 63), the clinical model achieved moderate performances to predict regional and/or distant recurrence with C-statistics from 0.53 to 0.59 (95% CI, 0.41, 0.67). The radiomic (original_firstorder_Entropy, original_gldm_LowGrayLevelEmphasis and original_glcm_DifferenceAverage) model achieved higher predictive ability in the training set and kept the same performance in the testing sets, with C-statistics from 0.70 to 0.78 (95% CI, 0.63, 0.88) while the combined model performs moderately well with C-statistics from 0.50 to 0.62 (95% CI, 0.37, 0.69).

CONCLUSION

Radiomic features extracted from pre-SBRT analog and digital [18F]FDG PET/CT outperform clinical parameters in the prediction of regional and/or distant recurrence and to discuss an adjuvant systemic treatment in ES-NSCLC. Prospective validation of our models should now be carried out.

Five-Year Survival Outcomes After Carbon-Ion Radiotherapy for Operable Stage I NSCLC: A Japanese National Registry Study (J-CROS-LUNG)

INTRODUCTION

The standard therapy for stage I NSCLC is surgery, but some operable patients refuse this option and instead undergo radiotherapy. Carbon-ion radiotherapy (CIRT) is a type of radiotherapy. The Japanese prospective nationwide registry study on CIRT began in 2016. Here, we analyzed real-world clinical outcomes of CIRT for operable patients with stage I NSCLC.

METHODS

All patients with operable stage I NSCLC treated with CIRT in Japan between 2016 and 2018 were enrolled. The dose fractionations for CIRT were selected from several options approved by the Japanese Society for Radiation Oncology. CIRT was delivered to the primary tumor, not to lymph nodes.

RESULTS

The median follow-up period was 56 months. Among 136 patients, 117 (86%) had clinical stage IA NSCLC and 19 (14%) had clinical stage IB NSCLC. There were 50 patients (37%) diagnosed clinically without having been diagnosed histologically. Most tumors (97%) were located in the periphery. The 5-year overall survival, cause-specific survival, progression-free survival, and local control rate were 81.8% (95% confidence interval [CI]: 75.1-89.2), 91.2% (95% CI: 86.0-96.8), 65.9% (95% CI: 58.2-74.6), and 95.8% (95% CI: 92.3-99.5), respectively. Multivariate analysis identified age as a significant factor for overall survival (p = 0.018), whereas age and consolidation/tumor ratio (p = 0.010 and p = 0.004) were significant factors for progression-free survival. There was no grade 4 or higher toxicity. Grade 3 radiation pneumonitis occurred in one patient.

CONCLUSIONS

This study reports the long-term outcomes of CIRT for operable NSCLC in the real world. CIRT for operable patients has been found to have favorable outcomes, with tolerable toxicity.

Optimal Radiation Therapy Fractionation Regimens for Early-Stage Non-Small Cell Lung Cancer

PURPOSE

A series of radiobiological models were developed to study tumor control probability (TCP) for stereotactic body radiation therapy (SBRT) of early-stage non-small cell lung cancer (NSCLC) per the Hypofractionated Treatment Effects in the Clinic (HyTEC) working group. This study was conducted to further validate 3 representative models with the recent clinical TCP data ranging from conventional radiation therapy to SBRT of early-stage NSCLC and to determine systematic optimal fractionation regimens in 1 to 30 fractions for radiation therapy of early-stage NSCLC that were found to be model-independent.

METHODS AND MATERIALS

Recent clinical 1-, 2-, 3-, and 5-year actuarial or Kaplan-Meier TCP data of 9808 patients from 56 published papers were collected for radiation therapy of 2 to 4 Gy per fraction and SBRT of early-stage NSCLC. This data set nearly triples the original HyTEC sample, which was used to further validate the HyTEC model parameters determined from a fit to the clinical TCP data.

RESULTS

TCP data from the expanded data set are well described by the HyTEC models with α/β ratios of about 20 Gy. TCP increases sharply with biologically effective dose and reaches an asymptotic maximal plateau, which allows us to determine optimal fractionation schemes for radiation therapy of early-stage NSCLC.

CONCLUSIONS

The HyTEC radiobiological models with α/β ratios of about 20 Gy determined from the fits to the clinical TCP data for SBRT of early-stage NSCLC describe the recent TCP data well for both radiation therapy of 2 to 4 Gy per fraction and SBRT dose and fractionation schemes of early-stage NSCLC. A steep dose response exists between TCP and biologically effective dose, and TCP reaches an asymptotic maximum. This feature results in model-independent optimal fractionation regimens determined whenever safe for SBRT and hypofractionated radiation therapy of early-stage NSCLC in 1 to 30 fractions to achieve asymptotic maximal tumor control, and T2 tumors require slightly higher optimal doses than T1 tumors. The proposed optimal fractionation schemes are consistent with clinical practice for SBRT of early-stage NSCLC.

Predictive clinical and dosimetric parameters for risk of relapse in early-stage non-small cell lung cancer treated by SBRT: A large single institution experience

Purpose

To evaluate the impact of dosimetric parameters on efficacy of stereotactic body radiation therapy (SBRT) in early-stage non-small cell lung cancer (ES-NSCLC), using Hypofractionated Treatment Effects in the Clinic (HyTEC) reporting standards.

Methods

From April 2010 to December 2020, 497 patients who received SBRT for ES-NSCLC at the University Hospital of Liège were retrospectively enrolled. A total dose of 40 to 60 Gy in 3-5 fractions (72-180 Gy biologically effective dose with an α/β ratio of 10 (BED10)) was prescribed to the 80 % isodose line of the PTV. Potential clinical and dosimetric predictors of recurrence, overall survival (OS) and disease specific survival (DSS) were evaluated using univariate and multivariate analyses.

Results

After a median follow-up of 32 months (range 3-143 months), the local control and disease-free survival (DFS) rates at 3 years were 91 % (95 % CI: 90 %-93 %) and 75 % (95 % CI: 73 %-77 %), respectively. The median OS was 41.6 months and the median DSS was not reached. On multivariate analysis, a higher gross tumor volume (GTV) Dmax (BED10) (cut-off 198 Gy) and a larger percent of the GTV receiving ≥110 % of the prescribed dose were predictive of a better local control, only GTV volume was correlated with DSS and no parameter was correlated with OS and regional or distant recurrences.

Conclusion

Lung SBRT for ES-NSCLC in 3 to 5 fractions resulted in high local control rates. A higher percent of GTV receiving ≥110 % of the prescribed dose and a higher GTV Dmax (BED10) seem to allow a better local control.

Stereotactic body radiotherapy in lung cancer: a contemporary review

The treatment of early stage non-small cell lung cancer (NSCLC) has improved enormously in the last two decades. Although surgery is not the only choice, lobectomy is still the gold standard treatment type for operable patients. For inoperable patients stereotactic body radiotherapy (SBRT) should be offered, reaching very high local control and overall survival rates. With SBRT we can precisely irradiate small, well-defined lesions with high doses. To select the appropriate fractionation schedule it is important to determine the size, localization and extent of the lung tumor. The introduction of novel and further developed planning (contouring guidelines, diagnostic image application, planning systems) and delivery techniques (motion management, image guided radiotherapy) led to lower rates of side effects and more conformal target volume coverage. The purpose of this study is to summarize the current developments, randomised studies, guidelines about lung SBRT, with emphasis on the possibility of increasing local control and overall rates in "fit," operable patients as well, so SBRT would be eligible in place of surgery.

Long-Term Outcomes of Ablative Carbon-Ion Radiotherapy for Central Non-Small Cell Lung Cancer: A Single-Center, Retrospective Study

The aim of this study is to assess the efficacy and safety of ablative carbon ion radiotherapy (CIRT) for early stage central non-small cell lung cancer (NSCLC). We retrospectively reviewed 30 patients who had received CIRT at 68.4 Gy in 12 fractions for central NSCLC in 2006-2019. The median age was 75 years, and the median Karnofsky Performance Scale score was 90%. All patients had concomitant chronic obstructive pulmonary disease, and 20 patients (67%) were considered inoperable. In DVH analysis, the median lung V5 and V20 were 15.5% and 10.4%, and the median Dmax, D0.5cc, D2cc of proximal bronchial tree was 65.6 Gy, 52.8 Gy, and 10.0 Gy, respectively. At a median follow-up of 43 months, the 3-year overall survival, disease-specific survival, and local control rates were 72.4, 75.8, and 88.7%, respectively. Two patients experienced grade 3 pneumonitis, but no grade ≥3 adverse events involving the mediastinal organs occurred. Ablative CIRT is feasible and effective for central NSCLC and could be considered as a treatment option, especially for patients who are intolerant of other curative treatments.

Pulmonary interstitial lymphography: A prospective trial with potential impact on stereotactic ablative radiotherapy planning for early-stage lung cancer

This prospective feasibility trial investigated pulmonary interstitial lymphography to identify thoracic primary nodal drainage (PND). A post-hoc analysis of nodal recurrences was compared with PND for patients with early-stage lung cancer; larger studies are needed to establish correlation. Exploratory PND-inclusive stereotactic ablative radiotherapy plans were assessed for dosimetric feasibility.

Recommendation on the technical and dosimetric data to be included in stereotactic body radiation therapy clinical trial publications based on a systematic review

The results of phase II and III trials on Stereotactic Body Radiation Therapy (SBRT) increased adoption of SBRT worldwide. The ability to replicate clinical trial outcomes in routine practice depends on the capability to reproduce technical and dosimetric procedures used in the clinical trial. In this systematic review, we evaluated if peer-reviewed publications of clinical trials in SBRT reported sufficient technical data to ensure safe and robust implementation in real world clinics. Twenty papers were selected for inclusion, and data was extracted by a working group of medical physicists created following the ESTRO 2021 physics workshop. A large variability in technical and dosimetric data were observed, with frequent lack of required information for reproducing trial procedures. None of the evaluated studies were judged completely reproducible from a technical perspective. A list of recommendations has been provided by the group, based on the analysis and consensus process, to ensure an adequate reproducibility of technical parameters in primary SBRT clinical trials. Future publications should consider these recommendations to assist transferability of the clinical trial in real world practice.

Exploring published and novel pre-treatment CT and PET radiomics to stratify risk of progression among early-stage non-small cell lung cancer patients treated with stereotactic radiation

PURPOSE

Disease progression after definitive stereotactic body radiation therapy (SBRT) for early-stage non-small cell lung cancer (NSCLC) occurs in 20-40% of patients. Here, we explored published and novel pre-treatment CT and PET radiomics features to identify patients at risk of progression.

MATERIALS/METHODS

Published CT and PET features were identified and explored along with 15 other CT and PET features in 408 consecutively treated early-stage NSCLC patients having CT and PET < 3 months pre-SBRT (training/set-aside validation subsets: n = 286/122). Features were associated with progression-free survival (PFS) using bootstrapped Cox regression (Bonferroni-corrected univariate predictor: p ≤ 0.002) and only non-strongly correlated predictors were retained (|Rs|<0.70) in forward-stepwise multivariate analysis.

RESULTS

Tumor diameter and SUVmax were the two most frequently reported features associated with progression/survival (in 6/20 and 10/20 identified studies). These two features and 12 of the 15 additional features (CT: 6; PET: 6) were candidate PFS predictors. A re-fitted model including diameter and SUVmax presented with the best performance (c-index: 0.78; log-rank p-value < 0.0001). A model built with the two best additional features (CTspiculation1 and SUVentropy) had a c-index of 0.75 (log-rank p-value < 0.0001).

CONCLUSIONS

A re-fitted pre-treatment model using the two most frequently published features - tumor diameter and SUVmax - successfully stratified early-stage NSCLC patients by PFS after receiving SBRT.

Comparison of Treatment Outcomes Between Thoracoscopic Surgery and Stereotactic Body Radiotherapy for Early-Stage Non-Small Cell Lung Cancer

Objective: To compare the risk of death, tumor recurrence, metastasis, and disease progression in early-stage non-small cell lung cancer (NSCLC) patients treated with thoracoscopic surgery and stereotactic body radiotherapy (SBRT). Methods: Patients who underwent radical surgery and SBRT for NSCLC between April 2010 and November 2021 were retrospectively analyzed. Continuous and categorical variables were compared using the Mann-Whitney U and Chi-square test, respectively. Kaplan-Meier curves were used to evaluate the survival outcomes of each patient group. Cox proportional hazard regression analyses were performed to estimate the risk of death, tumor recurrence, metastasis, and disease progression. Results: A total of 167 patients were enrolled, of whom 75 and 92 underwent SBRT and surgery, respectively. The median follow-up was 45 months (range, 4-105 months). SBRT patients were observed to be significantly older (median, 76.0 vs 67.0 years; P < .001), and associated with significantly higher mortality rate (42.7% vs 26.1%, P = .024). However, no significant difference in overall survival duration was seen between the SBRT and surgery groups (45.0 vs 41.0 months; P = .199). SBRT patients demonstrated significantly lower rates of metastasis (12.0% vs 30.4%, P = .004), and significantly longer metastasis-free survival (39.0 months vs 35.5 months, P = .020). The remaining outcomes, including tumor recurrence and disease progression rates, were similar between the groups. Compared to surgery, SBRT did not significantly associate with death, recurrence, or disease progression. Kaplan-Meier curves showed significant differences in overall, tumor recurrence-free, and disease progression-free survival between the groups (log-rank P < .05). Conclusions: SBRT demonstrated similar overall survival compared to radical surgery, and associated with significantly reduced risk of tumor metastasis. Our study thereby suggests SBRT as the best treatment option for patients with inoperable NSCLC.

An accurate prediction of negative lymph node metastasis with consideration of glucose metabolism in early-stage non-small cell lung cancer

OBJECTIVE

We aimed to identify risk factors in lymph node metastasis in early-stage non-small cell lung cancer (NSCLC) and predict lymph node metastasis.

METHODS

A total of 416 patients with clinical stage IA2-3 NSCLC who underwent lobectomy and lymph node dissection between July 2016 and December 2020 at National Cancer Center Hospital East were included. Multivariable logistic regression was performed to develop a model for predicting lymph node metastasis. Leave-one-out cross-validation was performed to evaluate the developing prediction model, and sensitivity, specificity, and concordance statistics were calculated to evaluate its diagnostic performance.

RESULTS

The formula for calculating the probability of pathological lymph node metastasis included SUVmax of the primary tumor and serum CEA level. The concordance statistics was 0.7452. When the cutoff value associated with the risk of incorrectly predicting pathological lymph node metastasis was 7.2%, the diagnostic sensitivity and specificity for predicting metastasis were 96.4% and 38.6%, respectively.

CONCLUSIONS

We created a prediction model for lymph node metastasis in NSCLC by combining the SUVmax of the primary tumor and serum CEA levels, which showed a particularly strong association. This model is clinically useful as it successfully predicts negative lymph node metastasis in patients with clinical stage IA2-3 NSCLC.

Creation, evolution, and future challenges of ion beam therapy from a medical physicist's viewpoint (Part 3): Chapter 3. Clinical research, Chapter 4. Future challenges, Chapter 5. Discussion, and Conclusion

Clinical studies of ion beam therapy have been performed at the Lawrence Berkeley Laboratory (LBL), National Institute of Radiological Sciences (NIRS), Gesellschaft für Schwerionenforschung (GSI), and Deutsches Krebsforschungszentrum (DKFZ), in addition to the development of equipment, biophysical models, and treatment planning systems. Although cancers, including brain tumors and pancreatic cancer, have been treated with the Bevalac's neon-ion beam at the LBL (where the first clinical research was conducted), insufficient results were obtained owing to the limited availability of neon-ion beams and immaturity of related technologies. However, the 184-Inch Cyclotron's helium-ion beam yielded promising results for chordomas and chondrosarcomas at the base of the skull. Using carbon-ion beams, NIRS has conducted clinical trials for the treatment of common cancers for which radiotherapy is indicated. Because better results than X-ray therapy results have been obtained for lung, liver, pancreas, and prostate cancers, as well as pelvic recurrences of rectal cancer, the Japanese government recently approved the use of public medical insurance for carbon-ion radiotherapy, except for lung cancer. GSI obtained better results than LBL for bone and soft tissue tumors, owing to dose enhancement enabled by scanning irradiation. In addition, DKFZ compared treatment results of proton and carbon-ion radiotherapy for these tumors. This article summarizes a series of articles (Parts 1-3) and describes future issues of immune ion beam therapy and linear energy transfer optimization.

Lobectomy versus proton therapy for stage I non-small cell lung cancer

OBJECTIVE

Lobectomy is the standard treatment for patients with early-stage non-small cell lung cancer (NSCLC). In recent years, an increasing number of patients with lung cancer have been treated using proton therapy (PT). We conducted a propensity score-matched analysis to compare the treatment outcomes of these 2 modalities.

METHODS

We retrospectively reviewed data from 275 patients with histologically confirmed clinical stage I NSCLC who underwent lobectomy (n = 206) or PT (n = 69) at our institution from July 2013 to December 2020. The end points were overall survival (OS), cause-specific survival, recurrence-free survival (RFS), local control, regional lymph node control, and distant control. Propensity score matching was performed to reduce selection bias in the 2 groups.

RESULTS

The matched cohort consisted of 59 patients who underwent lobectomy and 59 patients who underwent PT with a median follow-up period of 50 months. There were no significant differences in OS (P = .26), cause-specific survival (P = .33), RFS (P = .53), local control (P = .41), regional lymph node control (P = .98), and distant control (P = .31). In the lobectomy and PT groups, the 5-year OS rate was 85.8% and 79.1%, respectively, the RFS rate was 82.3% and 77.8%, and the local control rate was 92.1% and 96.6%.

CONCLUSIONS

We found no difference in survival or disease control between lobectomy and PT in patients with histologically confirmed clinical stage I NSCLC. Despite these findings, the potential for unmeasured confounding factors remains, and randomized control trials are needed to better compare these treatment modalities.

Biomedical advances and future prospects of high-precision three-dimensional radiotherapy and four-dimensional radiotherapy

Biomedical advances of external-beam radiotherapy (EBRT) with improvements in physical accuracy are reviewed. High-precision (±1 mm) three-dimensional radiotherapy (3DRT) can utilize respective therapeutic open doors in the tumor control probability curve and in the normal tissue complication probability curve instead of the one single therapeutic window in two-dimensional EBRT. High-precision 3DRT achieved higher tumor control and probable survival rates for patients with small peripheral lung and liver cancers. Four-dimensional radiotherapy (4DRT), which can reduce uncertainties in 3DRT due to organ motion by real-time (every 0.1-1 s) tumor-tracking and immediate (0.1-1 s) irradiation, have achieved reduced adverse effects for prostate and pancreatic tumors near the digestive tract and with similar or better tumor control. Particle beam therapy improved tumor control and probable survival for patients with large liver tumors. The clinical outcomes of locally advanced or multiple tumors located near serial-type organs can theoretically be improved further by integrating the 4DRT concept with particle beams.

Reirradiation with stereotactic body radiotherapy for primary or secondary lung malignancies: Tumor control probability and safety analyses

BACKGROUND

Reirradiation with stereotactic body radiotherapy (SBRT) for patients with primary or secondary lung malignancies represents an appealing definitive approach, but its feasibility and safety are not well defined. The purpose of this study was to investigate the tumor control probability (TCP) and toxicity for patients receiving reirradiation with SBRT.

PATIENTS AND METHODS

Eligible patients with recurrence of primary or secondary lung malignancies from our hospital were subjected to reirradiation with SBRT, and PubMed- and Embase-indexed articles were reviewed. The patient characteristics, pertinent SBRT dosimetric details, local tumor control, and toxicities were extracted. The logistic dose-response models were compared for TCP and overall survival (OS) in terms of the physical dose and three-, four-, and five-fraction equivalent doses.

RESULTS

The data of 17 patients from our hospital and 195 patients extracted from 12 articles were summarized. Reirradiation with SBRT yielded 2-year estimates of 80% TCP for doses of 50.10 Gy, 55.85 Gy, and 60.54 Gy in three, four, and five fractions, respectively. The estimated TCP with common fractionation schemes were 50%, 60%, and 70% for 42.04 Gy, 47.44 Gy, and 53.32 Gy in five fractions, respectively. Similarly, the 2-year estimated OS was 50%, 60%, and 70% for 41.62 Gy, 46.88 Gy, and 52.55 Gy in five fractions, respectively. Central tumor localization may be associated with severe toxicity.

CONCLUSIONS

Reirradiation with SBRT doses of 50-60 Gy in 3-5 fractions is feasible for appropriately selected patients with recurrence of peripheral primary or secondary lung malignancies, but should be carefully considered for centrally-located tumors due to potentially severe toxicity. Further studies are warranted for optimal dose/fractionation schedules and more accurate selection of patients suitable for reirradiation with SBRT.

Sublobar Resection versus Stereotactic Body Radiation Therapy for Clinical Stage I Non-Small Cell Lung Cancer: A Study Using Data from the Korean Nationwide Lung Cancer Registry

PURPOSE

Stereotactic body radiotherapy (SBRT) had been increasingly recognized as a favorable alternative to surgical resection in patients with high risk for surgery. This study compared survival outcomes between sublobar resection (SLR) and SBRT for clinical stage I non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

Data were obtained from the Korean Association of Lung Cancer Registry, a sampled nationwide database. This study retrospectively reviewed 382 patients with clinical stage I NSCLC who underwent curative SLR or SBRT from 2014 to 2016.

RESULTS

Of the patients, 43 and 339 underwent SBRT and SLR, respectively. Patients in the SBRT group were older and had worse pulmonary function. The 3-year overall survival (OS) rate was significantly better in the SLR group compared with the SBRT group (86.6% vs. 57%, log-rank p < 0.001). However, after adjusting for age, sex, tumor size, pulmonary function, histology, smoking history, and adjuvant therapy, treatment modality was not an independent prognostic factor for survival (hazard ratio, 0.99; 95% confidence interval, 0.43 to 2.77; p=0.974). We performed subgroup analysis in the following high-risk populations: patients who were older than 75 years; patients who were older than 70 years and had diffusing capacity of lung for carbon monoxide ≤ 80%. In each subgroup, there were no differences in OS and recurrence-free survival between patients who underwent SLR and those who received SBRT.

CONCLUSION

In our study, there were no significant differences in terms of survival or recurrence between SBRT and SLR in medically compromised stage I NSCLC patients. Our findings suggest that SBRT could be considered as a potential treatment option for selected patients.

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

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

[Stereotactic radiotherapy for operable stage I non-small cell lung cancer]

Standard treatment stage of non-small cell lung cancer is currently surgery. For inoperable patients, stereotactic body radiotherapy is the reference treatment. This non-invasive technique has developed considerably and its excellent results in terms of carcinological control and tolerance raise the question of its indication for operable patients, especially for old patients and/or with comorbidities. This article reviews the available data in the literature of the place of stereotactic body radiotherapy for medically operable patients with stage I non-small cell lung cancer.

Radiomic analysis for early differentiation of lung cancer recurrence from fibrosis in patients treated with lung stereotactic ablative radiotherapy

Objective. The development of radiation-induced fibrosis after stereotactic ablative radiotherapy (SABR) can obscure follow-up images and delay detection of a local recurrence in early-stage lung cancer patients. The objective of this study was to develop a radiomics model for computer-assisted detection of local recurrence and fibrosis for an earlier timepoint (<1 year) after the SABR treatment.Approach. This retrospective clinical study included CT images (n= 107) of 66 patients treated with SABR. A z-score normalization technique was used for radiomic feature standardization across scanner protocols. The training set for the radiomics model consisted of CT images (66 patients; 22 recurrences and 44 fibrosis) obtained at 24 months (median) follow-up. The test set included CT-images of 41 patients acquired at 5-12 months follow-up. Combinations of four widely used machine learning techniques (support vector machines, gradient boosting, random forests (RF), and logistic regression) and feature selection methods (Relief feature scoring, maximum relevance minimum redundancy, mutual information maximization, forward feature selection, and LASSO) were investigated. Pyradiomics was used to extract 106 radiomic features from the CT-images for feature selection and classification.Main results. An RF + LASSO model scored the highest in terms of AUC (0.87) and obtained a sensitivity of 75% and a specificity of 88% in identifying a local recurrence in the test set. In the training set, 86% accuracy was achieved using five-fold cross-validation. Delong's test indicated that AUC achieved by the RF+LASSO is significantly better than 11 other machine learning models presented here. The top three radiomic features: interquartile range (first order), Cluster Prominence (GLCM), and Autocorrelation (GLCM), were revealed as differentiating a recurrence from fibrosis with this model.Significance. The radiomics model selected, out of multiple machine learning and feature selection algorithms, was able to differentiate a recurrence from fibrosis in earlier follow-up CT-images with a high specificity rate and satisfactory sensitivity performance.

A Case of Radiation-Associated Vertebral Compression Fracture Mimicking Solitary Bone Metastasis of Lung Cancer

Radiation therapy plays an important role in the treatment of lung cancer. Although adverse effects of radiation are well known, they are sometimes difficult to be diagnosed. We report a case of a radiation-associated vertebral compression fracture which mimicked bone metastasis of lung cancer. The patient was a 57-year-old man diagnosed with lung squamous cell carcinoma (cT1aN2M0, c-stage IIIA). He received concurrent chemoradiotherapy (CRT) in combination with 6 weeks of weekly carboplatin plus paclitaxel and thoracic radiation of 60 Gy/30 fractions, followed by bi-weekly durvalumab for 12 months. On the last day of the 12-month durvalumab regimen, he complained of backache. Magnetic resonance imaging showed compression fracture of the seventh thoracic vertebra with the spinal cord compressed, and fluorine-18 fluorodeoxyglucose positron emission tomography and computed tomography demonstrated weak focal uptake only at the seventh thoracic vertebra. Although the fracture had been suspected to be bone metastasis, surgical biopsy revealed no evidence of malignancy. Since the seventh thoracic vertebra was included in the irradiation area, the patient was diagnosed with a radiation-associated fracture. Dual-energy X-ray absorptiometry of the lumbar vertebrae (L2 - 4) after the surgery revealed osteopenia. In conclusion, we successfully diagnosed the radiation-associated vertebral fracture caused by radical CRT. The fracture mimicked bone metastasis in preoperative imaging tests. Thus, surgical biopsy was useful for diagnosis.

Cost-effectiveness of stereotactic body radiotherapy versus conventional fractionated radiotherapy for medically inoperable, early-stage non-small cell lung cancer

BACKGROUND

Stereotactic body radiotherapy (SBRT) is a novel radio-therapeutic technique that has recently emerged as standard-of-care treatment for medically inoperable, early-stage non-small cell lung cancer (NSCLC). In this study, we compared the cost-effectiveness of SBRT with that of conventional fractionated radiotherapy (CFRT) in patients with medically inoperable, early-stage NSCLC from the perspective of the Chinese health system.

METHODS

A Markov model was developed to describe health states of patients after treatment with SBRT and CFRT. The recurrence risks, treatment toxicities, and utilities inputs were obtained from the literature. The costs were based on listed prices and real-world evidence. A simulation was conducted to determine the post-treatment lifetime years. For each treatment, the total costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs) per QALY were calculated. Deterministic and probabilistic sensitivity analyses were performed to assess the uncertainty of the model parameters.

RESULTS

In the base case analysis, SBRT was associated with a mean cost of USD16,933 and 2.05 QALYs, whereas CFRT was associated with a mean cost of USD17,726 and 1.61 QALYs. SBRT is a more cost-effective strategy compared with CFRT for medically inoperable, early-stage NSCLC, with USD 1802 is saved for every incremental QALY. This result was validated by DSA and PSA, in which SBRT remained the most cost-effective option.

CONCLUSIONS

The findings suggested that, compared to CFRT, SBRT may be considered a more cost-effective strategy for medically inoperable, early-stage NSCLC.

Smart Sensors and Microtechnologies in the Precision Medicine Approach against Lung Cancer

BACKGROUND AND RATIONALE

The therapeutic interventions against lung cancer are currently based on a fully personalized approach to the disease with considerable improvement of patients' outcome. Alongside continuous scientific progresses and research investments, massive technologic efforts, innovative challenges, and consolidated achievements together with research investments are at the bases of the engineering and manufacturing revolution that allows a significant gain in clinical setting.

AIM AND METHODS

The scope of this review is thus to focus, rather than on the biologic traits, on the analysis of the precision sensors and novel generation materials, as semiconductors, which are below the clinical development of personalized diagnosis and treatment. In this perspective, a careful revision and analysis of the state of the art of the literature and experimental knowledge is presented.

RESULTS

Novel materials are being used in the development of personalized diagnosis and treatment for lung cancer. Among them, semiconductors are used to analyze volatile cancer compounds and allow early disease diagnosis. Moreover, they can be used to generate MEMS which have found an application in advanced imaging techniques as well as in drug delivery devices.

CONCLUSIONS

Overall, these issues represent critical issues only partially known and generally underestimated by the clinical community. These novel micro-technology-based biosensing devices, based on the use of molecules at atomic concentrations, are crucial for clinical innovation since they have allowed the recent significant advances in cancer biology deciphering as well as in disease detection and therapy. There is an urgent need to create a stronger dialogue between technologists, basic researchers, and clinicians to address all scientific and manufacturing efforts towards a real improvement in patients' outcome. Here, great attention is focused on their application against lung cancer, from their exploitations in translational research to their application in diagnosis and treatment development, to ensure early diagnosis and better clinical outcomes.

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

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