A framework for automated contour quality assurance in radiation therapy including adaptive techniques.

Contouring of targets and normal tissues is one of the largest sources of variability in radiation therapy treatment plans. Contours thus require a time intensive and error-prone quality assurance (QA) evaluation, limitations which also impair the facilitation of adaptive radiotherapy (ART). Here, an automated system for contour QA is developed using historical data (the 'knowledge base'). A pilot study was performed with a knowledge base derived from 9 contours each from 29 head-and-neck treatment plans. Size, shape, relative position, and other clinically-relevant metrics and heuristically derived rules are determined. Metrics are extracted from input patient data and compared against rules determined from the knowledge base; a computer-learning component allows metrics to evolve with more input data, including patient specific data for ART. Nine additional plans containing 42 unique contouring errors were analyzed. 40/42 errors were detected as were 9 false positives. The results of this study imply knowledge-based contour QA could potentially enhance the safety and effectiveness of RT treatment plans as well as increase the efficiency of the treatment planning process, reducing labor and the cost of therapy for patients.

Lack of association of cadherin expression and histopathologic type, metastasis, or patient outcome in oropharyngeal squamous cell carcinoma: a tissue microarray study.

Altered cadherin expression is important for metastasis in many carcinomas including head and neck squamous cell carcinoma (SCC). We evaluated E- and N-cadherin expression specifically in oropharyngeal SCC and correlated this with clinical and pathologic features. Oropharyngeal SCC patients with clinical follow up information were identified from clinician databases from 1996 through 2007 and tissue microarrays created. Tumors had been previously typed histopathologically as keratinizing, non-keratinizing, or non-keratinizing with maturation, and had known p16 and human papillomavirus status, respectively. Immunohistochemistry was performed on the microarrays, and staining was evaluated for presence and intensity (0 = negative, 1 = weak, 2 = moderate, 3 = strong) both visually and also with digital image analysis software. Of 154 cases, E-cadherin was expressed in 152 (98.7%) and N-cadherin in 17 (11.5%). Neither E- nor N-cadherin expression was statistically significantly associated with histopathologic type (P = 0.082 and P = 0.228, respectively). E-cadherin staining intensity was not statistically significantly associated with nodal or distant metastasis, either visually or by image analysis, (P = 0.098 and P = 0.963 respectively) nor was N-cadherin (P = 0.228 and P = 0.935 respectively). Neither E- nor N-cadherin expression was associated with death from disease (P = 0.995; P = 0.964, respectively). E-cadherin is extensively expressed by oropharyngeal SCC, even the non-keratinizing type. Our results suggest that cadherin expression may not be a predictor for nodal or distant metastasis in these tumors. Mechanisms independent of cadherin expression may be important for metastases in oropharyngeal SCC.

Iodine-131-labeled antitenascin monoclonal antibody 81C6 treatment of patients with recurrent malignant gliomas: phase I trial results.

PURPOSE: To determine the maximum-tolerated dose (MTD) of iodine 131 (131I)-labeled 81C6 monoclonal antibody (mAb) in brain tumor patients with surgically created resection cavities (SCRCs) and to identify any objective responses to this treatment. METHODS: In this phase I trial, eligible patients were treated with a single injection of 131I-labeled 81C6. Cohorts of three to six patients were treated with escalating dosages of 131I (starting dose of 20 mCi with a 20-mCi escalation in subsequent cohorts) administered through an Ommaya reservoir in the SCRC. Patients were followed up for toxicity and response until death or for a minimum of 1 year after treatment. The SCRC patients, who were previously irradiated, were followed up without additional treatment unless progressive disease was identified. RESULTS: We administered 36 treatments of 131I doses up to 120 mCi to 34 previously irradiated patients with recurrent or metastatic brain tumors. Dose-limiting toxicity was reached at 120 mCi and was limited to neurologic or hematologic toxicity. None of the patients treated with less than 120 mCi developed significant neurologic toxicity; one patient developed major hematologic toxicity (MHT). The estimated median survival for patients with glioblastoma multiforme (GBM) and for all patients was 56 and 60 weeks, respectively. CONCLUSION: The MTD for administration of 131I-labeled 81C6 into the SCRCs of previously irradiated patients with recurrent primary or metastatic brain tumors was 100 mCi. The dose-limiting toxicity was neurologic toxicity. We are encouraged by the minimal toxicity and survival in this phase I trial. Radiolabeled mAbs may improve the current therapy for brain tumor patients.