Evaluation of the performance of both machine learning models using PET and CT radiomics for predicting recurrence following lung stereotactic body radiation therapy: A single-institutional study.

PURPOSE: Predicting recurrence following stereotactic body radiotherapy (SBRT) for non-small cell lung cancer provides important information for the feasibility of the individualized radiotherapy and allows to select the appropriate treatment strategy based on the risk of recurrence. In this study, we evaluated the performance of both machine learning models using positron emission tomography (PET) and computed tomography (CT) radiomic features for predicting recurrence after SBRT. METHODS: Planning CT and PET images of 82 non-small cell lung cancer patients who performed SBRT at our hospital were used. First, tumors were delineated on each CT and PET of each patient, and 111 unique radiomic features were extracted, respectively. Next, the 10 features were selected using three different feature selection algorithms, respectively. Recurrence prediction models based on the selected features and four different machine learning algorithms were developed, respectively. Finally, we compared the predictive performance of each model for each recurrence pattern using the mean area under the curve (AUC) calculated following the 0.632+ bootstrap method. RESULTS: The highest performance for local recurrence, regional lymph node metastasis, and distant metastasis were observed in models using Support vector machine with PET features (mean AUC = 0.646), Naive Bayes with PET features (mean AUC = 0.611), and Support vector machine with CT features (mean AUC = 0.645), respectively. CONCLUSIONS: We comprehensively evaluated the performance of prediction model developed for recurrence following SBRT. The model in this study would provide information to predict the recurrence pattern and assist in making treatment strategies.

Impact of Systemic Autoimmune Diseases on Treatment Outcomes and Radiation Toxicities in Patients with Stage I Non-Small Cell Lung Cancer Receiving Stereotactic Body Radiation Therapy: A Matched Case-Control Analysis.

We aimed to evaluate the impact of systemic autoimmune diseases (SADs) on treatment outcomes and radiation toxicities following stereotactic body radiation therapy (SBRT) for stage I non-small cell lung cancer (NSCLC). We queried an institution-based database on patients with SADs treated with SBRT for lung cancer between 2001 and 2016 (SAD group). Each patient was matched to three controls without SADs. The primary outcomes of interest were the overall survival (OS) and local control rate (LCR). The secondary outcomes were radiation toxicities of grades ≥2 (≥G2). Twelve patients with SADs were matched to 36 controls. The median follow-up duration was 3.6 years. There was a significant intergroup difference in the OS (hazard ratio [HR]: 4.11, 95% confidence incidence [CI]: 1.82−9.27, p < 0.001) and LCR (HR: 15.97, 95% CI: 2.89−88.29, p < 0.001). However, there were no significant intergroup differences in the odds of acute (odds ratio [OR]: 0.38, 95% CI: 0.02−8.91, p = 0.550) and late (OR: 2.20, 95% CI: 0.32−15.10, p = 0.422) ≥G2 radiation pneumonitis. No other ≥G2 toxicities were identified. In conclusion, although radiation toxicities are not enhanced by SADs, SADs are risk factors of poor prognosis following SBRT for stage I NSCLC.

Modified Glasgow Prognostic Score is predictive of prognosis for non-small cell lung cancer patients treated with stereotactic body radiation therapy: a retrospective study.

We aimed to assess the predictive value of the modified Glasgow prognostic score (mGPS) in patients with non-small cell lung cancer (NSCLC) who underwent stereotactic body radiation therapy (SBRT). We retrospectively reviewed the records of 207 patients, with a median age of 79 years. The pretreatment mGPS was calculated and categorized as high (mGPS = 1-2) or low (mGPS = 0). The median follow-up duration was 40.7 months. The five-year overall survival (OS), progression-free survival (PFS) and time to progression (TTP) rates were 44.3%, 36% and 54.4%, respectively. Multivariate analysis revealed that mGPS was independently predictive of OS (hazard ratio [HR] 1.67; 95% confidence interval 1.14-2.44: P = 0.009), PFS (HR 1.58; 1.10-2.28: P = 0.014) and TTP (HR 1.66; 1.03-2.68: P = 0.039). Patients who had high mGPS showed significantly worse OS (33.3 vs 64.5 months, P = 0.003) and worse PFS (23.8 vs 39 months, P = 0.008) than those who had low mGPS. The data showed a trend that patients with high mGPS suffered earlier progression compared to those with low mGPS (54.3 vs 88.1 months, P = 0.149). We confirmed that mGPS is independently predictive of prognosis in NSCLC patients treated with SBRT.

Tumor volume shrinkage during stereotactic body radiotherapy is related to better prognoses in patients with stage I non-small-cell lung cancer.

The purpose of the study was to investigate the association between tumor volume changes during stereotactic body radiation therapy (SBRT) and prognoses in stage I non-small-cell lung cancer (NSCLC). This retrospective review included stage I NSCLC patients in whom SBRT was performed at a total dose of 48.0-50.5 Gy in four or five fractions. The tumor volumes observed on computed tomography (CT) simulation and on the CT performed at the last treatment session using a CT-on-rails system were measured and compared. Then, the tumor volume changes during the SBRT period were measured and assessed for their association with prognoses (overall survival, local control, lymph node metastases and distant metastases). A total of 98 patients with a mean age of 78.6 years were enrolled in the study. The T-stage was T1a in 42%, T1b in 32% and T2a in 26% of the cases. The gross tumor volume (GTV) shrank and increased ≥10% in 23 (23.5%) and 36 (36.7%) of the cases, respectively. The 5-year local control and overall survival rates in the groups with a tumor shrinkage of ≥10% vs the group with a shrinkage of <10% were 94.7 vs 70.8% and 85.4 vs 47.6%, respectively; these differences were significant, with a P-value < 0.05. During a short SBRT period, the tumor shrank or enlarged in a small number of cases. A decrease of ≥10% in the GTV during SBRT was significantly related to better overall survival and local control.

Stereotactic body radiotherapy in patients with lung tumors composed of mainly ground-glass opacity.

We retrospectively reviewed the effect of stereotactic body radiation therapy (SBRT) in patients with stage I lung cancer whose lung tumor showed a nodular appearance of ground glass opacity, so-called ground glass nodule (GGN). A total of 84 patients (42 men, 42 women; mean age, 75 years) with stage I lung cancer with GGN accompanying a solid component <50% in diameter of the tumor and no metastases were studied. Concerning histology, 32 tumors were adenocarcinoma, 1 was squamous cell carcinoma, 2 were unclassified carcinoma and 49 cases were histology-unproven but increased in size or had a positive finding in 18F-FDG positron emission tomography (PET) examination. The median tumor size was 20 mm (range, 10-41 mm). All of the patients were treated with SBRT, and the total prescribed dose at the isocenter ranged between 48 Gy in four fractions and 84 Gy in ten fractions. Median follow-up duration was 33 months. No patient had local failure nor regional lymph node failure. The 3-year rate of distant failure was 2.6%. Two patients who experienced distant metastases had a past surgical history of initial lung cancer before SBRT. The rates of cause-specific and overall survival at 3 years were 98.2 and 94.6%, respectively. Treatment-related adverse events of ≥grade 4 were not reported. Although more cases and longer follow-ups are mandatory, SBRT may be one of the radical treatment options for patients with GGN.

Assessment of abdominal organ motion using cine magnetic resonance imaging in different gastric motilities: a comparison between fasting and postprandial states.

This study assessed abdominal organ motion induced by gastroduodenal motilities in volunteers during fasting and postprandial states, using cine magnetic resonance imaging (cine-MRI). Thirty-five volunteers underwent cine-MRI while holding their breath in the fasting and postprandial states. Gastric motility was quantified by the amplitude and velocity of antral peristaltic waves. Duodenal motility was evaluated as the change of duodenal diameter. Abdominal organ motion was measured in the liver, pancreas and kidneys. Motion was quantified by calculating maximal organ displacement in the left-right, antero-posterior and caudal-cranial directions. Median antral amplitude and velocity in the fasting and postprandial states were 7.7 and 15.1 mm (P < 0.01), and 1.3 and 2.5 mm/s (P < 0.01), respectively. Duodenal motility did not change. Median displacement for all organs ranged from 0.9 to 2.9 mm in the fasting state and from 1.0 to 2.9 mm in the postprandial state. Significant increases in abdominal organ displacement in the postprandial state were observed in the right lobe of the liver, pancreatic head and both kidneys. Differences in the median displacement of these organs between the two states were all <1 mm. Although the motion of several abdominal organs increased in the postprandial state, the difference between the two states was quite small. Thus, our study suggests that treatment planning and irradiation need not include strict management of gastric conditions, nor the addition of excess margins to compensate for differences in the intra-fractional abdominal organ motion under different gastric motilities in the fasting and postprandial states.

Renal Cancer is Not Radioresistant: Slowly but Continuing Shrinkage of the Tumor After Stereotactic Body Radiation Therapy.

PURPOSE: To evaluate the safety and efficacy of stereotactic body radiation therapy for primary lesion of renal cell carcinoma with long-term and regular follow-up of tumor size and renal function. METHODS: This prospective study included 13 patients treated with stereotactic body radiation therapy for primary lesion of stage I renal cell carcinoma between August 2007 and June 2016 in our institution. Diagnosis of renal cell carcinoma was made by 2 radiologists using computed tomography or magnetic resonance imaging. A dosage of 60 Gy in 10 fractions or 70 Gy in 10 fractions was prescribed. The higher dose was selected if dose constraints were satisfied. Tumor response on imaging examination, local progression-free rate, overall survival, and toxicity were assessed. RESULTS: The mean follow-up period was 48.3 months (range: 11-108 months). The tumors showed very slow but continuous response during long-term follow-up. Three cases (23.1%) showed transient progression during the short follow-up. The mean duration until the day on which partial response was confirmed among the partial or complete response cases was 22.6 months (95% confidence interval, 15.3-30.0 months). Local progression-free rate was 92.3% for 3 years and overall survival rate 91.7% for 2 years and 71.3% for 3 years. Twelve cases (92.3%) had impaired renal function at baseline. Renal function decreased slowly and mildly in most of the cases, but 2 cases of solitary kidney showed grade 4 or 5 renal dysfunction. CONCLUSION: All renal tumors decreased in size slowly but continuously for years after stereotactic body radiation therapy. Renal cancer can be treated radically with stereotactic body radiation therapy as a radiosensitive tumor, but careful attention should be given in cases with solitary kidney.

Serious gastric perforation after second stereotactic body radiotherapy for peripheral lung cancer that recurred after initial stereotactic body radiotherapy: a case report.

BACKGROUND: In recent reports, re-irradiation with stereotactic body radiotherapy for lung tumors in patients previously treated with thoracic radiation therapy resulted in several serious toxicities. Serious non-lung toxicities were observed mostly in patients with central tumors, but we experienced a case of fatal gastric perforation after a second stereotactic body radiotherapy in a patient with a peripheral lung tumor. CASE PRESENTATION: An 83-year-old Asian man was diagnosed with T2N0M0 lung cancer in the form of squamous cell carcinoma in the lower lobe of his left lung. He was treated with stereotactic body radiotherapy of 40 Gy in 4 fractions and the tumor decreased in size in partial response. The local tumor recurred 8 months after the first stereotactic body radiotherapy, and he was re-irradiated with a second stereotactic body radiotherapy of 50 Gy in 4 fractions. A Sengstaken-Blakemore tube was inserted below his diaphragm by laparoscopic surgery before the second stereotactic body radiotherapy in order to reduce the stomach dose by keeping his stomach apart from the tumor. Two months after the second stereotactic body radiotherapy, he developed fatal gastric perforation and gastropleural fistula penetrating his diaphragm. CONCLUSIONS: To the best of our knowledge, this is the first report about a gastric perforation after stereotactic body radiotherapy for lung tumors and it warns of serious complication of stereotactic body radiotherapy in not only centrally located but also peripherally located tumors like in this case.