Adjuvant Radiotherapy after Breast Conserving Treatment for Breast Cancer: A Dosimetric Comparison between Volumetric Modulated Arc Therapy and Intensity Modulated Radiotherapy.

BACKGROUND: Radiotherapy is an important treatment of choice for breast cancer patients after breast- conserving surgery, and we compare the feasibility of using dual arc volumetric modulated arc therapy (VMAT2), single arc volumetric modulated arc therapy (VMAT1) and Multi-beam Intensity Modulated Radiotherapy (M-IMRT) on patients after breast-conserving surgery. MATERIALS AND METHODS: Thirty patients with breast cancer (half right-sided and half left-sided) treated by conservative lumpectomy and requiring whole breast radiotherapy with tumor bed boost were planned with three different radiotherapy techniques: 1) VMAT1; 2) VMAT2; 3) M-IMRT. The distributions for the planning target volume (PTV) and organs at risk (OARs) were compared. Dosimetries for all the techniques were compared. RESULTS: All three techniques satisfied the dose constraint well. VMAT2 showed no obvious difference in the homogeneity index (HI) and conformity index (CI) of the PTV with respect to M-IMRT and VMAT1. VMAT2 clearly improved the treatment efficiency and can also decrease the mean dose and V5Gy of the contralateral lung. The mean dose and maximum dose of the spinal cord and contralateral breast were lower for VMAT2 than the other two techniques. The very low dose distribution (V1Gy) of the contralateral breast also showed great reduction in VMAT2 compared with the other two techniques. For the ipsilateral lung of right-sided breast cancer, the mean dose was decreased significantly in VMAT2 compared with VMAT1 and M-IMRT. The V20Gy and V30Gy of the ipsilateral lung of the left- sided breast cancer for VMAT2 showed obvious reduction compared with the other two techniques. The heart statistics of VMAT2 also decreased considerably compared to VMAT1 and M-IMRT. CONCLUSIONS: Compared to the other two techniques, the dual arc volumetric modulated arc therapy technique reduced radiation dose exposure to the organs at risk and maintained a reasonable target dose distribution.

Computed tomography manifestations of histologic subtypes of retroperitoneal liposarcoma.

OBJECTIVE: Liposarcoma (LPS) is the most common soft tissue sarcoma and accounts for approximately 20% of all mesenchymal malignancies, often occurring in deep soft tissue of retroperitoneal space. Accurate preoperative diagnosis is therefore necessary. We explored whether computed tomography (CT) could be used to differentiate between the various types of retroperitoneal liposarcoma (RPLS). METHOD: Forty-seven cases of RPLS, diagnosed surgically and histologically, were analyzed retrospectively. CT features were correlated with postoperative pathological appearance. RESULTS: The study radiologist identified 29, 11, 2, 2 and 3 RPLS as atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL), dedifferentiated liposarcoma (DDL), myxoid/round cell liposarcoma (ML/RCL), pleomorphic liposarcoma (PL) and mixed-type liposarcoma. Analysis of CT scans revealed the following typical findings of the different subtypes of RPLS: ALT/WDL was mainly visible as a well-delineated fatty hypodense tumor with uniform density and integrity margin; DDL was marked by the combination of focal nodular density and hypervascularity. ML/RCL, PL and mixed liposarcoma showed malignant biological behaviour and CT findings need further studies. CONCLUSIONS: CT scanning can reveal important details including internal components, margins and surrounding tissues. Based on CT findings, tumor type can be roughly evaluated and biopsy location and therapeutic scheme guided.

AT-406, an IAP inhibitor, activates apoptosis and induces radiosensitization of normoxic and hypoxic cervical cancer cells.

IAP antagonists increased the antitumor efficacy of X-irradiation in some types of cancers, but their effects on hypoxic cancer cells remain unclarified. We aims to investigate the radiosensitizing effect of an IAP inhibitor AT-406 on cervical cancer cell lines under both normoxia and hypoxia conditions. Hela and Siha cells were treated to investigate the effects of drug administration on cell proliferation, apoptosis, and radiosensitivity. Western blot analysis was used to determine the role of AT-406 in inhibition of IAPs. The pathway of apoptosis was characterized by caspases activity assay. AT-406 potently sensitized Hela cells but not Siha cells to radiation under normoxia. Notably, the radiosensitizing effect of AT-406 on hypoxic cells was more evident than on normoxic cells in both cell lines. Further mechanism studies by western blot showed that under normoxia AT-406 decreased the level of cIAP1 in Hela cells in a dose-dependent manner; while additional downregulation of XIAP expression was induced by AT-406 treatment under hypoxia in both cell lines. Finally, AT-406 works on both extrinsic death receptor and intrinsic mitochondrial apoptosis pathways to activate apoptosis. Totally, AT-406 acts as a strong radiosensitizer in human cervical cancer cells, especially in hypoxic condition.

Fenofibrate increases radiosensitivity in head and neck squamous cell carcinoma via inducing G2/M arrest and apoptosis.

Radiation therapy is an important treatment for head and neck squamous cell carcinoma (HNSCC). However, how to promote radiation sensitivity in HNSCC remains a challenge. This study aimed to investigate the radiosensitizing effects of fenofibrate on HNSCC and explore the underlying mechanisms. HNSCC cell lines CNE-2 and KB were subjected to ionizing radiation (IR), in the presence or absence of fenofibrate treatment. Cell growth and survival, apoptosis and cell cycle were evaluated. In addition, CNE-2 cells were xenografted into nude mice and subjected to IR and/ or fenofibrate treatment. The expression of cyclinB and CDK1 was detected by Western blotting. Our results showed that fenofibrate efficiently radiosensitized HNSCC cells and xenografts in mice, and induced apoptosis and G2/M arrest via reducing the activity of the CDK1/cyclinB1 kinase complex. These data suggest that fenofibrate could be a promising radiosensitizer for HNSCC radiotherapy.

Association of four polymorphisms in the death receptor 4 gene with cancer risk: an updated meta-analysis.

To date, no scientific consensus about the associations of DR4 C626G, A683C, A1322G, and G422A polymorphisms with cancer risk has been reached. Therefore, we conducted a meta-analysis to assess the associations. This meta-analysis involved 16 studies, of which 15 (4,261 cases and 4,598 controls) described C626G genotypes, 8 (2,898 cases and 3,135 controls) described A683C genotypes, 6 (1,564 cases and 1,673 controls) described A1322G genotypes, and 5 (584 cases and 607 controls) described A683C genotypes. We associated all the four polymorphisms with cancer risk. The C626G polymorphism was associated with slightly elevated cancer risk in recession model comparison [odds ratio (OR)=1.12, 95 % confidence interval (CI)=1.00-1.26, P heterogeneity=0.425]. In the subgroup analysis by cancer type, significantly elevated cancer risks were found among groups with lung cancer for heterozygote comparison (OR=1.76, 95 % CI=1.00-3.09, P heterogeneity=0.863). The A1322G polymorphism was associated with significantly elevated cancer risk in the different models (heterozygote comparison: OR=1.21, 95 % CI=1.00-1.46, P heterogeneity=0.347; dominant model: OR=1.21, 95 % CI=1.01-1.46, P heterogeneity=0.189; allele model comparison for G allele vs. A allele: OR=1.17, 95 % CI=1.02-1.35, P heterogeneity=0.173). The A683C and G422A polymorphisms were not associated with cancer risk in all genetic models. The C626G and A1322G polymorphisms are associated with increased cancer risk, but the A683C polymorphism is rarely associated with cancer risk.