Radiobiological evaluation of simultaneously dose-escalated versus non-escalated intensity-modulated radiation therapy for patients with upper thoracic esophageal cancer.

OBJECTIVE: To compare the radiobiological response between simultaneously dose-escalated and non-escalated intensity-modulated radiation therapy (DE-IMRT and NE-IMRT) for patients with upper thoracic esophageal cancer (UTEC) using radiobiological evaluation. METHODS: Computed tomography simulation data sets for 25 patients pathologically diagnosed with primary UTEC were used in this study. DE-IMRT plan with an escalated dose of 64.8 Gy/28 fractions to the gross tumor volume (GTV) and involved lymph nodes from 25 patients pathologically diagnosed with primary UTEC, was compared to an NE-IMRT plan of 50.4 Gy/28 fractions. Dose-volume metrics, tumor control probability (TCP), and normal tissue complication probability for the lung and spinal cord were compared. In addition, the risk of acute esophageal toxicity (AET) and late esophageal toxicity (LET) were also analyzed. RESULTS: Compared with NE-IMRT plan, we found the DE-IMRT plan resulted in a 14.6 Gy dose escalation to the GTV. The tumor control was predicted to increase by 31.8%, 39.1%, and 40.9% for three independent TCP models. The predicted incidence of radiation pneumonitis was similar (3.9% versus 3.6%), and the estimated risk of radiation-induced spinal cord injury was extremely low (<0.13%) in both groups. Regarding the esophageal toxicities, the estimated grade ≥2 and grade ≥3 AET predicted by the Kwint model were increased by 2.5% and 3.8%. Grade ≥2 AET predicted using the Wijsman model was increased by 14.9%. The predicted incidence of LET was low (<0.51%) in both groups. CONCLUSION: Radiobiological evaluation reveals that the DE-IMRT dosing strategy is feasible for patients with UTEC, with significant gains in tumor control and minor or clinically acceptable increases in radiation-induced toxicities.

Different definitions of esophagus influence esophageal toxicity prediction for esophageal cancer patients administered simultaneous integrated boost versus standard-dose radiation therapy.

We aim to evaluate whether different definitions of esophagus (DEs) impact on the esophageal toxicity prediction for esophageal cancer (EC) patients administered intensity-modulated radiation therapy with simultaneous integrated boost (SIB-IMRT) vs. standard-dose IMRT (SD-IMRT). The esophagus for 21 patients diagnosed with primary EC were defined in the following four ways: the whole esophagus, including the tumor (ESOwhole); ESOwhole within the treatment field (ESOinfield); ESOinfield, excluding the tumor (ESOinfield-tumor) and ESOwhole, excluding the tumor (ESOwhole-tumor). The difference in the dose variation, acute esophageal toxicity (AET) and late esophageal toxicity (LET) of four DEs were compared. We found that the mean esophageal dose for ESOwhole, ESOinfield, ESOinfield-tumor and ESOwhole-tumor were increased by 7.2 Gy, 10.9 Gy, 4.6 Gy and 2.0 Gy, respectively, in the SIB-IMRT plans. Radiobiological models indicated that a grade ≥ 2 AET was 2.9%, 3.1%, 2.2% and 1.6% higher on average with the Kwint model and 14.6%, 13.2%, 7.2% and 3.4% higher with the Wijsman model for the four DEs. A grade ≥ 3 AET increased by 4.3%, 7.2%, 4.2% and 1.2%, respectively. Additionally, the predicted LET increased by 0.15%, 0.39%, 1.2 × 10-2% and 1.5 × 10-3%. Our study demonstrates that different DEs influence the esophageal toxicity prediction for EC patients administered SIB-IMRT vs. SD-IMRT treatment.

[Detection of rearrangements of mixed lineage leukemia gene and its clinical significance].

To study the incidence, the types of fusion genes and the clinical significance of rearrangements of mixed lineage leukemia (MLL) gene in acute leukemia (AL), the rearrangements of MLL gene of 60 patients with AL were detected by fluorescence in situ hybridization (FISH) and 6 types of common fusion genes resulting from the rearrangements of MLL gene were detected by nested RT-PCR. The results showed that 7 out of 60 AL patients were found the rearrangements of MLL gene, the incidence of which was 11.67%. 2 out of 7 patients were diagnosed as AML-M(5), 5 patients were diagnosed as B-ALL. The fusion genes of the 2 AML-M(5) patients who had the rearrangements of MLL gene were MLL/AF(9). Among 5 B-ALL patients, 2 patients were confirmed to express MLL/ENL, 1 patient was confirmed to express MLL/AF(4), the other 2 patients did not express the fusion genes. It is concluded that FISH is a fast, specific and sensitive method to detect the rearrangements of MLL gene in AL patients and nested RT-PCR is a convenient and feasible method to detect the types of fusion genes resulting from the rearrangements of MLL gene. The detection of MLL gene rearrangement is of great importance in predicting prognosis and guiding therapy in AL.

[Heat stress characteristics of photosystem II in eggplant].

With lower-and higher heat-resistant varieties of eggplant (Solanum melongena L.) Heibei I and Heibei II as test materials, and by using Plant Efficiency Analyzer (PEA) from Hansatech, this paper measured the fast chlorophyll a fluorescence transient and its parameters. The results showed that PS II construction became more sensitive to heat stress when ambient temperature was higher than 40 degrees C. The F0 went up slowly, and Fv/Fm and deltaF/Fm' came down dramatically. Heibei II had a longer semi-attenuation temperature of Fv/Fm (T50) and deltaF/Fm' (t50) than Heibei I. Under strong heat stress (5 min at 48 degrees C or 20-30 min at 44 degrees C), the K-step in relation to the inactivation of oxygen-evolving complex appeared in fluorescence rise at about 700 micros, and the regular O-J-I-P transient was transformed to O-K-J-I-P one. The K-phase of Heibei I and Heibei II appeared when the treatment time was up to 20 and 30 minutes at 44 degrees C, respectively. In comparing with 35 degrees C heat treatment, the DI0/RC in the parameters of Strasser's specific energy fluxes model was increased by a great extent under 48 degrees C or more heat stress, reflecting a strong safeguard of energy dissipation to PS II. When the temperature of heat stress increased from 35 degrees C to 52 degrees C, the Fvi/Fv of PS II silent reaction centers of Heibei I and Heibei II increased remarkably.