Interobserver Variations in Target Delineation in Intensity-Modulated Radiation Therapy for Nasopharyngeal Carcinoma and its Impact on Target Dose Coverage.

BACKGROUND: To investigate the differences between physicians in target delineation in intensity-modulated radiation therapy for nasopharyngeal carcinoma as well as their impact on target dose coverage. METHODS: Ninety-nine in-hospital patients were randomly selected for retrospective analysis, and the target volumes were delineated by 2 physicians. The target volumes were integrated with the original plans, and the differential parameters, including the Dice similarity coefficient (DSC), Hausdorff distance (HD), and Jaccard similarity coefficient (JSC) were recorded. The dose-volume parameters to evaluate target dose coverage were analyzed by superimposing the same original plan to the 2 sets of images on which the target volumes were contoured by the 2 physicians. The significance of differences in target volumes and dose coverage were evaluated using statistical analysis. RESULTS: The target dose coverage for different sets of target volumes showed statistically significant differences, while the similarity metrics to evaluate geometric target volume differences did not. More specifically, for PGTVnx, the median DSC, JSC, and HD were 0.85, 0.74, and 11.73, respectively; for PCTV1, the median values were 0.87, 0.77, and 11.78, respectively; for PCTV2, the median values were 0.90, 0.82, and 16.12, respectively. For patients in stages T3-4, DSC, and JSC were reduced but HD was increased compared to those in stages T1-2. Dosimetric analysis indicated that, for the target volumes, significant differences between the 2 physicians were found in D95, D99, and V100 for all the target volumes (ie, PGTVnx, PCTV1, and PCTV2) across the whole group of patients, as well as in patients with disease stages T3-4 and T1-2. CONCLUSIONS: The target volumes delineated by the 2 physicians had a high similarity, but the maximal distances between the outer contours of the 2 sets were significantly different. In patients with advanced T stages, significant differences in dose distributions were found, stemming from the deviations of target delineation.

[Expression and prognostic value of transcriptional factor sp1 in breast cancer].

BACKGROUND & OBJECTIVE: Transcriptional factor Sp1 is involved in many biological processes, such as cell proliferation, apoptosis, differentiation and transformation, and plays an important role in invasion and metastasis of tumors. However, the expression patterns of Sp1 in various tumors are different. This study was to investigate the correlations of Sp1 expression to metastasis, invasion, and prognosis of breast cancer. METHODS: The expression of Sp1 in 60 specimens of breast cancer and 12 specimens of adjacent breast tissue was detected by EnVision immunohistochemistry. Its correlation to clinicopathologic features of breast cancer was analyzed by Cox regression analysis. RESULTS: The positive rate of Sp1 was 71.67% in breast cancer tissues, and 33.33% in adjacent tissues. Sp1 staining in cancer tissue was positively correlated to TNM stage (r=0.349, P<0.05), tumor invasion (r=0.407, P<0.01), and lymph node metastasis (r=0.314, P<0.05). Univariate analysis indicated that the overall survival rate was significantly lower in Sp1-positive patients than in Sp1-negative patients (41.86% vs. 82.35%, P<0.05). Cox multivariate analysis showed that Sp1 expression, TNM stage, invasion and lymph node metastasis were independent prognostic factors of breast cancer. CONCLUSIONS: Sp1 maybe participate in the invasion and metastasis of breast cancer, and is one of the valuable markers indicating poor prognosis of breast cancer. Sp1 detection, with consideration of tumor invasion and clinical stage, may increase the accuracy of predicting prognosis of patients with breast cancer.