Dynamic contrast enhanced­magnetic resonance imaging for the early evaluation of the response to docetaxel in rats with epithelial ovarian cancer.

Dynamic contrast enhanced­magnetic resonance imaging (DCE­MRI) contributes to the early detection and prediction of responses to chemotherapy in cancer. The aim of the present study was to investigate the feasibility of quantitative DCE­MRI parameters for noninvasively predicting the early response to DTX in epithelial ovarian cancer (EOC). In the present study, using 7,12­dimethylbenz (A) anthracene, orthotopic EOC was induced in Sprague Dawley rats. Rats with EOC were treated with docetaxel (DTX) on day 0. DCE­MRI was applied on days 0, 3, 7, 14 and 21. On day 21, the treated tumor types were categorized into sensitive and insensitive groups according to their change in size. Quantitative DCE­MRI parameters were used to assess the early response to therapy. The experiment was performed again, the treatment group was divided into sensitive and insensitive groups according to their initially obtained cut-off values, and histopathological analyses were performed. Comparing the sensitive group with the insensitive group, there were significant differences in the percentage change in the volume transfer constant (Ktrans), rate constant (kep) and initial area under the curve (IAUC) from day 3 and tumor size from day 14. During the early stages of treatment (on day 3), the percentage change of Ktrans combined with kep produced an AUC of 1, and a sensitivity and specificity of 100 and 100%, respectively, using a cut-off value of a 17.59% reduction in Ktrans and kep. From day 7, there were significant differences in the quantitative index percentage change in angiogenesis in the sensitive group compared with the insensitive group. The percentage change in Ktrans, kep and IAUC were positively correlated with the percentage of change in tumor size and angiogenesis, and negatively correlated with the percentage of change in necrosis. The results of the present study indicated that quantitative DCE­MRI parameters were superior to imaging tumor size for the early detection and prediction of the response to DTX chemotherapy in EOC.

Diffusion-weighted imaging and diffusion kurtosis imaging for early evaluation of the response to docetaxel in rat epithelial ovarian cancer.

BACKGROUND: To investigate diffusion-weighted magnetic imaging (DWI) and diffusion kurtosis magnetic imaging (DKI) for the early detection of the response to docetaxel (DTX) chemotherapy in rat epithelial ovarian cancer (EOC). METHODS: 7,12-Dimethylbenz[A]anthracene was applied to induce orthotopic EOC in Sprague-Dawley rats. Rats with EOC were treated with DTX on day 0 (treatment group) or were left untreated (control group). DWI and DKI were performed on days 0, 3, 7, 14 and 21 after treatment. On day 21, the tumors were categorized into the sensitive and insensitive groups according to the size change. The cutoff values of the DWI and DKI parameters for the early response were determined. The experiment was repeated, and the treatment group was divided into the sensitive and insensitive groups according to the initially obtained cutoff values. The DWI and DKI parameters were correlated with tumor size, proliferation, apoptosis and tumor necrosis. RESULTS: In the sensitive vs. insensitive or control group, significant differences were found in the Δ% of the DWI and DKI parameters (ADC, D and K) from day 3 and in tumor size from day 14. Early on day 7, the Δ% of K had an AUC of 1 and sensitivity and specificity values of 100% and 100%, respectively, to detect the response to DTX using a cutoff value of 19.03% reduction in K. From day 7, significant differences were found in the Δ% of Ki-67 and CA125 in the sensitive vs. control group and from day 14 in the sensitive vs. insensitive group. From day 14, there were significant differences in the Δ% of Bcl-2, apoptosis and tumor necrosis in the sensitive vs. control or insensitive group. The Δ% values of ADC and D were negatively correlated with the Δ% values of tumor size, Ki-67, CA125 and Bcl-2 and were positively correlated with the Δ% values of apoptosis and tumor necrosis. The Δ% of K was positively correlated with the Δ% values of tumor size, Ki-67, CA125 and Bcl-2 and was negatively correlated with the Δ% values of apoptosis and tumor necrosis. CONCLUSIONS: DWI and DKI parameters, especially K, are superior for imaging tumor size for the early detection of the response to DTX chemotherapy in induced rat EOC.

The value of DCE-MRI in assessing histopathological and molecular biological features in induced rat epithelial ovarian carcinomas.

BACKGROUND: To investigate dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) for assessing histopathological and molecular biological features in induced rat epithelial ovarian carcinomas (EOCs). METHODS: 7,12-dimethylbenz[A]anthracene (DMBA) was applied to induce EOCs in situ in 46 SD rats. Conventional MRI and DCE-MRI were performed to evaluate the morphology and perfusion features of the tumors, including the time-signal intensity curve (TIC), volume transfer constant (Ktrans), rate constant (Kep), extravascular extracellular space volume ratio (Ve) and initial area under the curve (IAUC). DCE-MRI parameters were correlated with histological grade, microvascular density (MVD), vascular endothelial growth factor (VEGF) and fraction of Ki67-positive cells and the serum level of cancer antigen 125 (CA125). RESULTS: Thirty-five of the 46 rats developed EOCs. DCE-MRI showed type III TIC more frequently than type II (29/35 vs. 6/35, p < 0.001) in EOCs. The two types of TIC of tumors had significant differences in the histological grade, MVD, expression of VEGF and Ki67, and the serum level of CA125 (all p < 0.01). Ktrans, Kep and IAUC values showed significant differences in different histological grades in overall and pairwise comparisons except for IAUC in grade 2 vs. grade 3 (all p < 0.01). There was no significant difference in Ve values among the three grade groups (p > 0.05). Ktrans, Kep and IAUC values were positively correlated with MVD, VEGF and Ki67 expression (all p < 0.01). Ve was not significantly correlated with MVD, VEGF expression, Ki67 expression and the CA125 level (all p > 0.05). CONCLUSIONS: TIC types and perfusion parameters of DCE-MRI can reflect tumor grade, angiogenesis and cell proliferation to some extent, thereby helping treatment planning and predicting prognosis.

[Radiosensitizing effect of erlotinib on human lung adenocarcinoma cell line A549].

OBJECTIVE: To explore the radiosensitizing effect of erlotinib on human lung adenocarcinoma cell line A549 cells and the related mechanisms. METHODS: The inhibitory effect of erlotinib on A549 cells was assessed by MTT assay, and its IC50 concentration was calculated. The radiosensitization was evaluated by the method of clone forming assay. Flow cytometry was used to analyze the effect of erlotinib on cell cycle and apoptosis. RESULTS: The growth of A549 cells was inhibited after the cells were exposed to erlotinib for 48 hours. Moreover, the inhibitory rates increased with the increase of erlotinib concentrations, and IC50 was 19.26 µmol/L. In contrast to the irradiation alone group, the survival rates of the cells in erlotinib plus irradiation groups decreased, and erlotinib enhanced the radiosensitivity of the A549 cells. This effect was further increased as cells were exposed to erlotinib for a longer time. In the irradiation alone group and the two groups exposed to erlotinib for 24 hours and 48 hours before irradiation, D0 values were 3.01 Gy, 2.58 Gy and 2.45 Gy respectively, and Dq values were 2.16 Gy, 1.94 Gy and 1.61 Gy, respectively. In the last two groups, SERD0 values were 1.17 and 1.23, respectively. The flow cytometry analysis showed that erlotinib induced G2/M phase arrest and increased the apoptosis rate in A549 cells. With the increase of exposure time, the effects were more significant. CONCLUSIONS: Erlotinib inhibits the A549 cell growth and enhances the radiosensitivity of A549 cells in vitro. The radiosensitizing mechanisms might be related to inhibiting repair of sublethal injury and inducing G2/M phase arrest and apoptosis.

[Concurrent radiotherapy combined with carboplatin and etoposide in limited stage small cell lung cancer].

OBJECTIVE: To observe the effect of concurrent radiotherapy combined with carboplatin and etoposide in limited stage small cell lung cancer. METHODS: Ninety patients with limited stage small cell lung cancer were randomized into two groups, concurrent treatment group (group A) and sequential treatment group (group B). All the patients in two groups received radiotherapy (60 Gy in 6 weeks) and six courses of chemotherapy (carboplatin and etoposide). Radiotherapy was started in the first course of chemotherapy in group A. Patients of group B were treated by radiation between the fourth and the fifth course of chemotherapy. RESULTS: The median survival time was 26 months in group A and 19 months in group B. The 5-year survival rate was 27% in group A and 16% in group B. The major toxic reactions were grade III-IV myelosuppression. The differences of two groups were significant (P < 0.05). CONCLUSION: Concurrent radiotherapy combined with carboplatin and etoposide can significantly improve median survival time and 5-year survival rate of patients with limited stage small cell lung cancer.