Stereotactic body radiotherapy for second primary lung cancer and intra-parenchymal lung metastasis in patients previously treated with surgery: evaluation of indications and predictors of decreased respiratory function

Synergistic combination of a topologically invariant imaging signature and a biomarker for the accurate prediction of symptomatic radiation pneumonitis before stereotactic ablative radiotherapy for lung cancer: A retrospective analysis

Objectives

We aimed to explore the synergistic combination of a topologically invariant Betti number (BN)-based signature and a biomarker for the accurate prediction of symptomatic (grade ≥2) radiation-induced pneumonitis (RP+) before stereotactic ablative radiotherapy (SABR) for lung cancer.

Methods

A total of 272 SABR cases with early-stage non-small cell lung cancer were chosen for this study. The occurrence of RP+ was predicted using a support vector machine (SVM) model trained with the combined features of the BN-based signature extracted from planning computed tomography (pCT) images and a pretreatment biomarker, serum Krebs von den Lungen-6 (BN+KL-6 model). In all, 242 (20 RP+ and 222 RP–(grade 1)) and 30 cases (8 RP+ and 22 RP–) were used for training and testing the model, respectively. The BN-based features were extracted from BN maps that characterize topologically invariant heterogeneous traits of potential RP+ lung regions on pCT images by applying histogram- and texture-based feature calculations to the maps. The SVM models were built to predict RP+ patients with a BN signature that was constructed based on the least absolute shrinkage and selection operator logistic regression model. The evaluation of the prediction models was performed based on the area under the receiver operating characteristic curves (AUCs) and accuracy in the test. The performance of the BN+KL-6 model was compared to the performance based on the BN, conventional original pCT, and wavelet decomposition (WD) models.

Results

The test AUCs obtained for the BN+KL-6, BN, pCT, and WD models were 0.825, 0.807, 0.642, and 0.545, respectively. The accuracies of the BN+KL-6, BN, pCT, and WD models were found to be 0.724, 0.708, 0.591, and 0.534, respectively.

Conclusion

This study demonstrated the comprehensive performance of the BN+KL-6 model for the prediction of potential RP+ patients before SABR for lung cancer.

Evaluation of lung tumor motion in a large sample: Target-related and clinical factors influencing tumor motion based on four-dimensional CT

Background and purpose

We aimed to analyze the influence of target‐related and clinical factors on lung tumor motion based on four‐dimensional CT (4DCT), and clarify the motion based on subgroups in lung stereotactic body radiation therapy.

Materials and methods

4DCT image data of 267 tumors from 246 patients were analyzed. The coordinates in the left–right (LR), anterior–posterior (AP), and cranial–caudal (CC) directions of the center of mass (COM) of the gross tumor volumes in 10 phases of 4DCT were measured. The peak‐to‐peak COM displacement in the LR, AP, CC, and 3D directions was calculated. The influence of target‐related and clinical factors on tumor motion was evaluated using multivariate analysis.

Results

The tumor segment location correlated with the tumor motion in each direction. Tumor size was predictive of tumor motion in the 3D (p = 0.023) and AP directions (p = 0.049). The tumor motion for metastatic tumors was smaller than that for primary tumors in the LR (p = 0.019) and AP directions (p = 0.008). The CC motion for pulmonary surgery recipients (3.8 ± 4.5 mm) was less than that for patients who had not undergone surgery (5.6 ± 5.4 mm), and no significant clinical factor was observed. BSA and BMI were positively correlated with the motion in the CC (p = 0.02) and LR directions (p = 0.002).

Conclusion

The tumor segment location was a good predictor of tumor motion. A larger tumor tends to have a smaller motion. Patients with metastatic tumors or those who have undergone pulmonary surgery exhibited smaller and more unpredictable tumor motions, which required individual assessments. Thus, clinical factors can potentially predict tumor motion.

Completion Pneumonectomy for Second Primary/Primary Lung Cancer and Local Recurrence Lung Cancer

BACKGROUND

Completion pneumonectomy (CP) for second primary/primary lung cancer (SPLC) and local recurrence lung cancer (LRLC) is still controversial. Although several case series on such a practice exist, the oncological benefit is under debate. The purpose of this study was to review available literatures on CP for SPLC and LRLC and evaluate postoperative and long-term outcomes.

METHODS

MEDLINE, SCOPUS and Web of Science were reviewed for eligible studies in January 2021. Studies were included if they indicated outcomes of patients with lung cancer undergoing CP. Overall survival (OS) was defined as the primary end point; secondary end points included operative morbidity and 30-day mortality. Random-effects meta-analysis based on a binomial distribution was used to create pooled estimates.

RESULTS

Thirty-two eligible studies including 1,157 patients were identified. These studies were uniformly retrospective reports. Pooled estimates for 3- and 5-year OS were 50.6% [95% confidence interval (CI) 34.7-66.5] and 38.9% [95% CI 32.2-46.1] in SPLC patients. When the SPLC was a stage I tumor, pooled 5-year OS was favorable with 60.7% [95% CI 43.2-75.9]. In LRLC, pooled 3- and 5-year OS were 47.6% [95% CI 36.1-59.4] and 33.8% (95% CI 26.8-41.5). Pooled morbidity and 30-day mortality was reported in 38.2% (95% CI 32.0-44.9), and 10.0% (95% CI 8.1-12.3).

CONCLUSIONS

CP for SPLC and LRLC is a challenging procedure with significant perioperative morbimortality. However, published evidence indicates good long-term survival for selected patients. Further studies are needed to identify patient subgroups which benefit most from CP.

Stereotactic body radiotherapy in patients with chronic obstructive pulmonary disease and interstitial pneumonia: a review

Stereotactic body radiation therapy (SBRT) can yield excellent local tumor control, as well as survival benefit comparable to that of surgery for early-stage lung cancer. However, in terms of toxicity, SBRT might lead to fatal radiation pneumonitis. Lung diseases, such as chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD), are major risk factors for lung cancer. However, these patients are typically not candidates for the gold-standard treatment option, lobectomy, because of the perioperative risks. In addition, patients with poor respiratory function can be excluded in prospective clinical trials. Thus, SBRT for patients with pulmonary diseases is still challenging, but there appears to be a clinical role for this modality as an alternative treatment. However, there are few well-documented review articles on SBRT for patients with pulmonary diseases. Therefore, we aimed to review SBRT in the context of important patient-related factors, including COPD and ILD. SBRT is an acceptable alternative treatment option for patients with lung cancer who also have COPD with an equivalent risk of radiation pneumonitis to normal lung. However, latent ILD should be detected prior to treatment. The indication for SBRT should be decided by carefully considering the risks and benefit for patients with ILD.