Statistical analysis of IMRT dosimetry quality assurance measurements for local delivery guideline

<p>Abstract</p> <p>Purpose</p> <p>To establish our institutional guideline for IMRT delivery, we statistically evaluated the results of dosimetry quality assurance (DQA) measurements and derived local confidence limits using the concept confidence limit of |mean|+1.96σ.</p> <p>Materials and methods</p> <p>From June 2006 to March 2009, 206 patients with head and neck cancer, prostate cancer, liver cancer, or brain tumor were treated using LINAC-based IMRT technique. In order to determine site specific DQA tolerances at a later stage, a hybrid plan with the same fluence maps as in the treatment plan was generated on CT images of a cylindrical phantom of acryl. Points of measurement using a 0.125 cm³ion-chamber were typically located in the region of high and uniform doses. The planar dose distributions perpendicular to the central axis were measured by using a diode array in solid water with all fields delivered, and assessed using gamma criteria of 3%/3 mm. The mean values and standard deviations were used to develop the local confidence and tolerance limits. The dose differences and gamma pass rates for the different treatment sites were also evaluated in terms of total monitor uints (MU), MU/cGy, and the number of PTV's pieces.</p> <p>Results</p> <p>The mean values and standard deviations of ion-chamber dosimetry differences between calculated and measured doses were -1.6 ± 1.2% for H&N cancer, -0.4 ± 1.2% for prostate and abdominal cancer, and -0.6 ± 1.5% for brain tumor. Most of measured doses (92.2%) agreed with the calculated doses within a tolerance limit of ±3% recommended in the literature. However, we found some systematic under-dosage for all treatment sites. The percentage of points passing the gamma criteria, averaged over all treatment sites was 97.3 ± 3.7%. The gamma pass rate and the agreement of ion-chamber dosimetry generally decreased with increasing the number of PTV's pieces, the degree of modulation (MU/cGy), and the total MU beyond 700. Our local confidence limits were comparable to those of AAPM TG 119 and ESTRO guidelines that were provided as a practical baseline for center-to-center commissioning comparison. Thus, our institutional confidence and action limits for IMRT delivery were set into the same levels of those guidelines.</p> <p>Discussion and Conclusions</p> <p>The systematic under-dosage were corrected by tuning up the MLC-related factors (dosimetric gap and transmission) in treatment planning system (TPS) and further by incorporating the tongue-and groove effect into TPS. Institutions that have performed IMRT DQA measurements over a certain period of time need to analyze their accrued DQA data. We confirmed the overall integrity of our IMRT system and established the IMRT delivery guideline during this procedure. Dosimetric corrections for the treatment plans outside of the action level can be suggested only with such rigorous DQA and statistical analysis.</p

Genetic and Epigenetic Marker-Based DNA Test of Stool Is a Promising Approach for Colorectal Cancer Screening

Colorectal cancer (CRC) is one of the most common malignancies and leading cause of cancer-related deaths in the world.1 However, it may be treated effectively by surgical removal of the cancerous tissue if detected at early stages. Conventional tools for screening CRC are either invasive or inaccurate. Therefore, there is an urgent need to develop a reliable screening tools for CRC to significantly reduce its morbidity. In this regard, a novel DNA markers-based detection in stool is emerging as a promising approach

Risk of recurrence in surgically resected stage I adenocarcinoma of the lung: histopathologic and immunohistochemical analysis

STUDY OBJECTIVES: Stage I adenocarcinoma of the lung is the most common type of lung cancer. A better understanding of the histopathology and molecular biology of lung cancer might improve the capability to predict the outcome for any individual patient. The purpose of this study was to evaluate several histopathologic and molecular markers in order to assess their prognostic value in stage I adenocarcinoma. METHODS: Fifty-five patients at the Seoul National University Bundang Hospital were enrolled in the study. Histopathologic factors and molecular markers were selected. RESULTS: Multivariate analysis demonstrated that necrosis, lymphatic vessel invasion, E-cadherin, p53, and Ki-67 emerged as independent prognostic factors of recurrence. When patients were grouped according to low or high risk according to the number of factors involved, the difference in disease-free survival between these groups was statistically significant. CONCLUSIONS: In resected stage I adenocarcinoma, necrosis, lymphatic vessel invasion, E-cadherin, and p53 have been identified as independent predictors of disease-free survival

The impact of sagittal balance on clinical results after posterior interbody fusion for patients with degenerative spondylolisthesis: A Pilot study

<p>Abstract</p> <p>Background</p> <p>Comparatively little is known about the relation between the sagittal vertical axis and clinical outcome in cases of degenerative lumbar spondylolisthesis. The objective of this study was to determine whether lumbar sagittal balance affects clinical outcomes after posterior interbody fusion. This series suggests that consideration of sagittal balance during posterior interbody fusion for degenerative spondylolisthesis can yield high levels of patient satisfaction and restore spinal balance</p> <p>Methods</p> <p>A retrospective study of clinical outcomes and a radiological review was performed on 18 patients with one or two level degenerative spondylolisthesis. Patients were divided into two groups: the patients without improvement in pelvic tilt, postoperatively (Group A; n = 10) and the patients with improvement in pelvic tilt postoperatively (Group B; n = 8). Pre- and postoperative clinical outcome surveys were administered to determine Visual Analogue Pain Scores (VAS) and Oswestry disability index (ODI). In addition, we evaluated full spine radiographic films for pelvic tilt (PT), sacral slope (SS), pelvic incidence (PI), thoracic kyphosis (TK), lumbar lordosis (LL), sacrofemoral distance (SFD), and sacro C7 plumb line distance (SC7D)</p> <p>Results</p> <p>All 18 patients underwent surgery principally for the relief of radicular leg pain and back pain. In groups A and B, mean preoperative VAS were 6.85 and 6.81, respectively, and these improved to 3.20 and 1.63 at last follow-up. Mean preoperative ODI were 43.2 and 50.4, respectively, and these improved to 23.6 and 18.9 at last follow-up. In spinopelvic parameters, no significant difference was found between preoperative and follow up variables except PT in Group A. However, significant difference was found between the preoperative and follows up values of PT, SS, TK, LL, and SFD/SC7D in Group B. Between parameters of group A and B, there is borderline significance on preoperative PT, preoperative LL and last follow up SS.</p> <p>Correlation analysis revealed the VAS improvements in Group A were significantly related to postoperative lumbar lordosis (Pearson's coefficient = -0.829; p = 0.003). Similarly, ODI improvements were also associated with postoperative lumbar lordosis (Pearson's coefficient = -0.700; p = 0.024). However, in Group B, VAS and ODI improvements were not found to be related to postoperative lumbar lordosis and to spinopelvic parameters.</p> <p>Conclusion</p> <p>In the current series, patients improving PT after fusion were found to achieve good clinical outcomes in degenerative spondylolisthesis. Overall, our findings show that it is important to quantify sagittal spinopelvic parameters and promote sagittal balance when performing lumbar fusion for degenerative spondylolisthesis.</p

Analysis of the predictive role and new proposal for surgical strategies based on the modified Tomita and Tokuhashi scoring systems for spinal metastasis

BACKGROUND: We sought to identify preoperative factors significantly correlated with survival. We also aimed to evaluate the validity of the prognostic scores in the Tomita and Tokuhashi systems and discuss several aspects to improve the predictive accuracy of these systems. Moreover, we suggest modified criteria for selecting treatment strategies. METHODS: In total, the outcomes of 112 patients with spinal metastasis who underwent surgery between January 2006 and June 2011 were retrospectively reviewed. The validity of the prognostic scores was assessed on the basis of their correlation with survival. For various primary malignancies, new scoring criteria were applied in each system according to the survival results obtained in this study. Each revised scoring system was adjusted with a similar principle of scoring as described previously. Patient survival according to each preoperative factor was analyzed by the Kaplan-Meier method. The predictive value of each scoring system was evaluated by the log-rank test and Cox regression analysis. RESULTS: The interval from the diagnosis of the primary malignancy to that of spinal metastasis (p = 0.023) and the interval from the diagnosis of spinal metastasis to surgery (p = 0.039) were significantly correlated with survival. Regarding Tokuhashi scores, the correlation coefficient was 0.790 before adjustment (p = 0.001) and 0.853 after adjustment (p < 0.001). For Tomita scores, the correlation coefficient was -0.994 (p < 0.001) both before and after adjustment. CONCLUSIONS: Tomita scores more accurately predicted survival than Tokuhashi scores. It is helpful to evaluate both scoring systems with adjustment for primary malignancy depending on the clinical setting. Patients with Tomita scores less than or equal to 8 and Tokuhashi scores greater than or equal to 6 are recommended to undergo surgical management

Epidermal Growth Factor Receptor Mutation and Pathologic-Radiologic Correlation Between Multiple Lung Nodules with Ground-Glass Opacity Differentiates Multicentric Origin from Intrapulmonary Spread

IntroductionNo standard guidelines detailing recommendations for the selection and treatment for multiple lung nodules with ground-glass opacity (GGO) have been established. For treatment decision, we analyzed epidermal growth factor receptor (EGFR)/K-ras somatic aberrations and pathologic-radiologic correlation in multiple lung nodules presented as GGO to differentiate multifocal lesions from intrapulmonary spread.MethodsTwenty-four patients with multiple lung nodules presented as GGO were identified to investigate somatic mutations of EGFR (exon 18–21) and K-ras (codons 2, 13, and 61). This series included 18 atypical adenomatous hyperplasias (AAH), 15 bronchioloalveolar carcinomas (BAC), and 23 adenocarcinomas (ADC) obtained from 24 patients.ResultsHigh frequency of discordant EGFR mutations (17 of 24, 70.8%) could discriminate tumor clonality (18 of 24, 75%) of multiple lung neoplastic nodules presented as GGO. EGFR mutations were common in AAH (38.9%), BAC (46.7%), and ADC (39.1%). In case 4, AAH and BAC had different mutational changes, and in case 10, the BAC lesion contains EGFR mutation that is not in the invasive ADC. In case 17, the BAC had more mutational changes than the carcinoma. The pure GGO appearance in the radiologic examination corresponded preinvasive pathologic change.ConclusionsThis study showed that synchronous BAC and/or ADC can have different EGFR or K-ras mutational profiles suggesting these lesions arise as independent events rather than intrapulmonary spread or systemic metastasis. This has significant implication in staging and treatment. These findings might be a clue to establish guidelines of the multiple neoplastic lung nodules with GGO

Diagnostic accuracy of CT-guided core biopsy of ground-glass opacity pulmonary lesions

The purpose of our study was to evaluate the accuracy of CT-guided percutaneous core biopsy of ground-glass opacity (GGO) pulmonary lesions. MATERIALS AND METHODS: The study included 50 patients (24 men, 26 women; age range, 43-78 years) who had a GGO pulmonary lesion and underwent CT-guided core biopsy. Diagnostic accuracy was compared between two groups according to lesion size ( or = 2 cm) and GGO component (> 90% vs 50-90%). Each case was reviewed for complications, including pneumothorax, thoracostomy tube insertion, and hemoptysis. RESULTS: Malignancy was finally diagnosed in 33 patients, including three who underwent repeated biopsies, with 33 true-positive and three false-negative findings for an overall sensitivity of 92% (33/36). A benign lesion was finally diagnosed in 10 patients with one false-positive result, for a specificity of 90%. Two benign lesions without confirmative diagnosis because of loss of follow-up and five nondiagnostic samples were excluded from the calculations of sensitivity, specificity, and diagnostic accuracy. The overall diagnostic accuracy was 91%, with a positive predictive value of 97% and a negative predictive value of 75%. Sensitivity and accuracy were not significantly different between the two groups of lesion size and GGO components (p = 0.0491). Ten (18%) patients had pneumothorax, with one (2%) requiring placement of a thoracostomy tube. Mild hemoptysis occurred in seven (13%) patients. CONCLUSION: CT-guided core biopsy of GGO lesions can yield high diagnostic accuracy and acceptable complication rates approaching those of solid lesions

Motor-Evoked Potential Confirmation of Functional Improvement by Transplanted Bone Marrow Mesenchymal Stem Cell in the Ischemic Rat Brain

This study investigated the effect of bone marrow mesenchymal stem cells (BMSCs) on the motor pathway in the transient ischemic rat brain that were transplanted through the carotid artery, measuring motor-evoked potential (MEP) in the four limbs muscle and the atlantooccipital membrane, which was elicited after monopolar and bipolar transcortical stimulation. After monopolar stimulation, the latency of MEP was significantly prolonged, and the amplitude was less reduced in the BMSC group in comparison with the control group (P < .05). MEPs induced by bipolar stimulation in the left forelimb could be measured in 40% of the BMSC group and the I wave that was not detected in the control group was also detected in 40% of the BMSC group. Our preliminary results imply that BMSCs transplanted to the ischemic rat brain mediate effects on the functional recovery of the cerebral motor cortex and the motor pathway

A Case of Synchronous Squamous Cell Carcinoma in the Esophagus and Stomach

Synchronous esophageal and gastric cancers with the pathologic features of a squamous cell carcinoma are extremely rare. A 57-year-old male visited our hospital with a history of hematemesis and was diagnosed with a synchronous cancer. He underwent a staging work-up, and the resectable lesion in the stomach was operated on following radiologic and endoscopic evaluations. The pathologic examination revealed a synchronous cancer consisting of squamous cell carcinoma in the distal esophagus and the cardia of the stomach. We report a case of a synchronous cancer that was successfully treated by surgical resection followed by concurrent chemoradiotherapy. We also discuss the hypothesis regarding the origin and presentation of the synchronous cancer and highlight the importance of careful surveillance by physicians at the time of diagnosis