Mitsuhiko Oguri

Staging liver fibrosis by using liver-enhancement ratio of gadoxetic acid-enhanced MR imaging: comparison with aspartate aminotransferase-to-platelet ratio index

OBJECTIVE To compare the diagnostic ability of gadoxetic acid-enhanced hepatocyte-phase MR images with aspartate aminotransferase-to-platelet ratio index (APRI) to predict liver fibrosis stage. MATERIALS AND METHODS Our study included 100 patients who underwent gadoxetic acid-enhanced MRI and either liver biopsy or liver surgery. Liver fibrosis stage was histologically determined according to the METAVIR system: F0 (n=16), F1 (n=17), F2 (n=10), F3 (n=21) and F4 (n=36). Four measures were used as imaging-based fibrosis markers: liver-spleen contrast ratio, liver-enhancement ratio, corrected liver-enhancement ratio and spleen index. APRI represented a blood test-based fibrosis marker. The diagnostic ability of those fibrosis markers were compared through receiver-operating characteristic analysis. RESULTS The area under the curve (AUC) for APRI prediction of severe fibrosis (≥F3 and F4) was significantly greater than that of corrected liver-enhancement ratio. However, corrected liver-enhancement ratio had a greater AUC for prediction of mild fibrosis (≥F1) than APRI, although the difference was insignificant. CONCLUSION Corrected liver-enhancement ratio with gadoxetic acid-enhanced MRI is correlated to the stage of liver fibrosis. APRI, however, has greater reliability for predicting severe fibrosis and cirrhosis than does the imaging-based fibrosis marker tested in this study.

Value of dual time point F-18 FDG-PET/CT imaging for the evaluation of prognosis and risk factors for recurrence in patients with stage I non-small cell lung cancer treated with stereotactic body radiation therapy

PURPOSE To investigate prognostic and risk factors for recurrence after stereotactic body radiation therapy (SBRT) in patients with stage I non-small cell lung carcinoma (NSCLC), focusing on dual time point [18]F-fluorodeoxyglucose positron emission tomography (FDG PET). MATERIALS AND METHODS We prospectively evaluated 57 patients with stage I NSCLC (45 T1N0M0 and 12 T2N0M0) who had undergone pretreatment FDG-PET/CT and were subsequently treated with SBRT. All patients received a whole-body PET/CT scan at 60 min and a whole-lung at 120 min after the injection. The maximum standardized uptake value (SUV) and retention index (RI) of the lesions were calculated. Local recurrence, regional lymph node metastasis, distant metastasis, and the recurrence pattern were evaluated. Cox proportional hazard regression analyses were performed to evaluate prognostic factors or risk factors of recurrence. RESULTS During the median follow-up period of 27 months, local recurrence, regional lymph node metastasis, and distant metastasis were seen in 17 (30%), 12 (21%), and 17 (30%) of the 57 patients, respectively. The 3-year overall survival rate was 63.4%. SUVmax did not affect any recurrence, DFS, OS, or CSS. RI significantly predicted higher distant metastasis (HR 47.546, p=0.026). In contrast, RI tended to predict lower local recurrence (HR 0.175, p=0.246) and regional lymph node metastasis (HR 0.109, p=0.115). CONCLUSIONS SUVmax at staging FDG-PET does not predict any recurrence, DFS, OS or CSS. In contrast, higher RI predicts higher distant metastasis and tended to predict lower local or regional lymph node metastasis.

Large prostate motion produced by anal contraction

BACKGROUND AND PURPOSE The aim of this study was to define the effects of voluntary anal contraction on prostate motion in an experimental setting. MATERIALS AND METHODS Thirty-eight patients (median age, 76 years) with prostate cancer underwent thin-slice computed tomography (CT) in the vicinity of the prostate before and after active anal contraction. Three-dimensional displacement of the pelvis and prostate was measured. RESULTS Mean (±standard deviation, SD) overall displacement of the prostate due to anal contraction was 0.3±1.4 mm to the right, 9.3±7.8 mm to the anterior, and 5±4 mm to the cranial direction. Mean displacement of the pelvis was 0.5±1.8 mm to the right, 4.1±7.1 mm to the anterior, and 1±3 mm to the cranial direction. Mean displacement of the prostate relative to the pelvis was 0.1±1.1 mm to the left, 5.2±3.3 mm to the anterior, and 4±4 mm to the cranial direction. CONCLUSIONS Voluntary anal contraction within an experimental setting induces large prostate and bone motion, mainly in the anterior and cranial directions. The frequency and magnitude of actual anal contractions during radiotherapy for prostate cancer need to be determined.

Serious gastric ulcer event after stereotactic body radiotherapy (SBRT) delivered with concomitant vinorelbine in a patient with left adrenal metastasis of lung cancer

Hypofractionated stereotactic body radiation therapy (SBRT) is a form of high-precision radiotherapy delivery characterized by: a) reproducible immobilization to avoid patient movement during treatment sessions; (b) measures to account for tumor motion during imaging, treatment planning, and radiation delivery; c) use of dose distributions tightly covering the tumor, with rapid dose fall-off in surrounding normal tissues, in order to reduce toxicity; and d) use of extremely high doses of radiation, usually delivered in a small number of treatment fractions within a short period. The main aim of SBRT is to acquire better local control of the tumor by providing a higher dose of irradiation to a specifi ed area during a short period. SBRT has been available for more than 10 years and is gaining clinical interest as a means of treating tumors in various organs, particularly for patients with stage I non-small cell lung cancer [1 – 6]. SBRT for oligometastases represents a new trend in radiation oncology [7,8]. It is also commonly accepted that SBRT is safe and frequently effective in such patients, including patients with adrenal gland metastases [9 – 11]. Although late effects in normal tissues after SBRT have been demonstrated [12 – 16], few papers have described the gastrointestinal late effects of SBRT. We describe and discuss herein a serious gastric ulcer event occurring after SBRT was delivered with concomitant vinorelbine in a patient with left adrenal metastasis of lung cancer. Clinical case

Stereotactic Body Radiotherapy for Metachronous Multisite Oligo-Recurrence: A Long-Surviving Case with Sequential Oligo-Recurrence in Four Different Organs Treated Using Locally Radical Radiotherapy and a Review of the Literature

Stereotactic body radiotherapy (SBRT) for oligometastases represents a recent trend in radiation oncology. While abundant data are available regarding the use of SBRT for the treatment of lung or liver oligometastases from various retrospective series and prospective trials, relatively little information has been accumulated for the treatment of oligometastases at sites other than the lungs and liver, particularly for sequential oligometastases in multiple organs. Oligometastases with primary lesions controlled is called “oligo-recurrence.” We describe herein the case of a lung cancer patient who developed repeated oligo-recurrence at multiple sites that were each controlled by radical radiotherapy and achieved long-term survival and discuss the merits of locally aggressive radiotherapy for this type of disease condition with reviewing the literature. Although further investigation should be undertaken to clarify the benefits, objectives, and methods of SBRT for the treatment of oligometastases, we believe utilization of SBRT may be worthwhile for patients with remote metastases who hope for treatment to acquire better local control and possible longer survival.

Immune responses following stereotactic body radiotherapy for stage I primary lung cancer.

Purpose. Immune responses following stereotactic body radiotherapy (SBRT) for stage I non-small cell lung cancer (NSCLC) were examined from the point of view of lymphocyte subset counts and natural killer cell activity (NKA). Patients and Methods. Peripheral blood samples were collected from 62 patients at 4 time points between pretreatment and 4 weeks post-treatment for analysis of the change of total lymphocyte counts (TLC) and lymphocyte subset counts of CD3+, CD4+, CD8+, CD19+, CD56+, and NKA. In addition, the changes of lymphocyte subset counts were compared between patients with or without relapse. Further, the correlations between SBRT-related parameters and immune response were analyzed for the purpose of revealing the mechanisms of the immune response. Results. All lymphocyte subset counts and NKA at post-treatment and 1 week post-treatment were significantly lower than pre-treatment (P < 0.01). No significant differences in the changes of lymphocyte subset counts were observed among patients with or without relapse. The volume of the vertebral body receiving radiation doses of 3 Gy or more (VV3) significantly correlated with the changes of nearly all lymphocyte subset counts. Conclusions. SBRT for stage I NSCLC induced significant immune suppression, and the decrease of lymphocyte subset counts may be associated with exposure of the vertebral bone marrow.

Magnetic resonance elastography for prediction of radiation‐induced liver disease after stereotactic body radiation therapy

Surgical resection and ablation are standard treatments for solitary hepatocellular carcinoma (HCC), but these methods are invasive, particularly for elderly patients. Stereotactic body radiation therapy (SBRT) is a noninvasive, curative treatment for HCC. Using SBRT, tumoricidal doses can be delivered to the tumor while sparing the non–tumorbearing liver; however, radiation-induced liver disease (RILD) after SBRT has been observed in some cases. Generally, RILD occurs within 4 months after irradiation and manifests as either 1) an anicteric elevation of alkaline phosphatase to at least twice the upper normal level and nonmalignant ascites or 2) an elevation of transaminases to at least five times the upper limit of the normal or pretreatment level. Careful attention must be paid during treatment to avoid RILD. Reported risk factors for RILD after SBRT include large gross tumor volume, the percentage of the non– tumor-bearing liver volume receiving >20 Gy (V20), Child-Pugh grade B or C, and hepatitis B virus– positive status; however, no predictive factors for RILD have been identified. Magnetic resonance elastography (MRE) is a recently developed method for measuring liver stiffness noninvasively. A recent study suggested that the degree of liver stiffness may identify patients with cirrhosis who are at a high risk of decompensation. To detect a new determinant risk factor of RILD, we retrospectively reviewed 17 patients who underwent SBRT (28-60 Gy in 4-10 fractions) for HCC (14-68 mm) with pretreatment MRE. Liver stiffness was measured in non–tumor-bearing liver parenchyma. Pretreatment liver stiffness of patients with RILD (n 5 4, median 8.3 kPa) was significantly higher than that of patients without RILD (n 5 13, median 5.0 kPa) (P 5 0.0090), and it was the only predictor of RILD after SBRT (Table 1). The elevation of alkaline phosphatase or transaminases in patients with RILD was improved during follow-up. No patients died of RILD. It is crucial to predict whether the liver can tolerate SBRT for HCC. Several studies have reported clinical parameters associated with RILD; however, there is no guideline regarding the indications for SBRT to avoid RILD. Therefore, these results are useful for demonstrating a determinant risk factor to consider when making treatment decisions. Although SBRT for HCC has not yet been accepted as a high priority in guidelines, it has become clear that great local control can be achieved by SBRT. Therefore, SBRT is an option for patients in our institution who do not wish to undergo a surgical procedure. This study is limited by the small number of patients; nonetheless, we conclude that MRE is a promising method of predicting RILD after SBRT.