Multivariate analysis by Cox proportional hazard model on prognosis of patient with epithelial ovarian cancer

PURPOSE OF INVESTIGATION

To evaluate the influence of various clinicopathological and biochemical factors on the survival of patients with epithelial ovarian cancer (EOC) after radical resection.

METHODS

A retrospective analysis was made for 183 cases of epithelial ovarian cancer treated from January 1997 to January 2001. Six clinicopathological factors, including menopause, histological type, histological grade, lymph node metastasis, FIGO stage and chemotherapy that could possibly influence survival were selected. The expression of COX-2 and VEGF protein as two biochemical factors were detected in EOC tissues using immunohistochemical staining. Independent variables were first analyzed by univariate methods. A multivariate analysis of these variables was performed using the Cox proportional hazard regression model.

RESULTS

The ovarian cumulative survival rate was 48.71% for three years and 30.71% for five years. Univariate analysis of overall survival involving all the patients indentified five factors that were associated with a significant outcome: menopause, histological grade, FIGO stage, COX-2 or VEGF expression level (p < 0.05). The expression of COX-2 was positive in 140 (76.5%) of these 183 cases, but was not associated with menopause, histological type, histological grade, lymph node metastasis or FIGO stage. Median survival time was 24.56 months for the patients with COX-2 positive expression, and 47.52 months for those with COX-2 negative expression (p < 0.05). VEGF protein overexpression was examined in 117 (63.93%) of all 183 cases, and was associated with lymph node metastasis (p <0.05), but not associated with menopause, histological grade, histological type or FIGO stage. The median survival time was 23.36 months for the patients with VEGF detected expression, and 42.09 months for those with no VEGF detected expression (p < 0.05). When the interactive effects of these factors were taken into account, COX-2 expression, FIGO stage, VEGF expression and histological grade were the four most important prognostic factors by multivariate analysis using the Cox proportional hazards model. Risk of death for the patients with COX-2 positive expression was 2.8 times than that with COX-2 negative expression, and for FIGO stage, VEGF expression and histological grade, risk of death was 2.2, 2.1, and 1.84 times, respectively.

CONCLUSION

COX-2 expression, FIGO stage, VEGF expression and histological grade are the most important prognostic factors for EOC after curative resection.

Recombinant Mycobacterium smegmatis expressing an ESAT6-CFP10 fusion protein induces anti-mycobacterial immune responses and protects against Mycobacterium tuberculosis challenge in mice

The currently used vaccine against tuberculosis, Bacille Calmette-Guérin (BCG), has variable efficacy, so new vaccine development is crucial. In this study, we evaluated a recombinant vaccine prepared from non-pathogenic Mycobacterium smegmatis (rMS) that expresses a fusion of early secreted antigenic target 6-kDa antigen (ESAT6) and culture filtrate protein 10 (CFP10). C57BL/6 mice were immunized with the rMS expressing the ESAT6-CFP10 fusion protein (rM.S-e6c10) or with BCG. The mice in the rM.S-e6c10 group had a significantly higher titre of anti-ESAT6-CFP10 antibodies than did animals in the BCG or saline groups. Spleen cells from rM.S-e6c10-immunized mice exhibited a cytotoxic response to ESAT6 and CFP10-expressed target cells, but spleen cells from animals in the other groups did not. Levels of IFN-γ and IL-2 production by purified T cells from spleens were significantly higher in rM.S-e6c10 group than in BCG group. Finally, after M. tuberculosis (MTB)-challenged mice, dramatic reduction in the numbers of MTB colony-forming units (CFUs) in the lungs was observed for the mice immunized with the rMS. The protective efficacy of rM.S-e6c10 and BCG vaccination was similar based on measures of MTB burden and lung pathology. Our data indicate that the recombinant M. smegmatis vaccine expressing the ESAT6-CFP10 fusion protein has potential in clinic application.

Addition of insulin lispro protamine suspension or insulin glargine to oral type 2 diabetes regimens: a randomized trial

AIMS

The addition of basal insulin to existing oral therapy can help patients with type 2 diabetes (T2D) achieve glycaemic targets. This study compares the efficacy and safety of insulin lispro protamine suspension (ILPS) and insulin glargine in insulin-naive patients with T2D and inadequate control on oral antihyperglycaemic medication (OAM).

MATERIALS AND METHODS

An open-label, randomized, multicentre, multinational 24-week study of 471 patients receiving ≥2 OAMs for ≥3 months with a body mass index between 25 and 45 kg/m(2) and HbA1c 7.5-10.0% was conducted. ILPS was injected once or twice daily vs. glargine injected once daily plus prestudy OAMs. Primary objective compared the HbA1c change from baseline.

RESULTS

HbA1c change from baseline to endpoint was similar in both groups [-1.46% (ILPS) and -1.41% (glargine)]. Least-squares mean difference (95% CI) for HbA1c (-0.05 [-0.21, 0.11]%), glycaemic variability (0.06 [-0.06, 0.19] mmol/l) and weight change (-0.01 [-0.61, 0.59] kg) showed non-inferiority (margins of 0.4%, 0.8 mmol/l and 1.5 kg, respectively). Percentages of patients achieving HbA1c <7.0% were 43.8% ILPS and 41.2% glargine. Mean daily insulin dose was 0.39 vs. 0.35 U/kg (p = 0.02) and weight gain was 1.04 vs. 1.07 kg for ILPS vs. glargine (p = 0.98). Overall hypoglycaemia (episodes/patient/year) was similar for ILPS and glargine (24.2 ± 28.8 vs. 23.0 ± 30.9); nocturnal (6.1 ± 10.6 vs. 4.1 ± 9.4, p < 0.001) rates were higher for ILPS. Severe hypoglycaemia was higher for ILPS vs. glargine (n = 9 vs. n = 2; p = 0.04).

CONCLUSIONS

At endpoint, ILPS was non-inferior to glargine in HbA1c change from baseline, but associated with increased risk of hypoglycaemia.

A practical method to detect target failure of a helical tomotherapy unit

PURPOSE

Helical tomotherapy has been in clinical use for several years. One of the issues with a helical tomotherapy unit is the failure of detection of the x-ray target. In this study, we are proposing a method to detect potential failure of the x-ray target.

METHODS

Currently, on-board detector data from a helical tomotherapy unit are collected and sent to TomoTherapy Inc. for comparison with the so-called gold standard for the unit. However, this is sometimes time-consuming. Furthermore, the clinical medical physicists have no access to this comparison procedure. In this study, we developed a practical method to detect target failure based on one of the monthly quality assurance (QA) procedures. The commissioning cross-plane profiles were used as the comparison baseline. Larger EDR2 film (35×43 cm) were set at source-axis distance (SAD) (85 cm) and shot with 1.5 cm solid water as build-up material and 10 cm solid water as backscattering material. Cross-plane profiles obtained from the EDR2 film were compared with the commissioning profiles.

RESULTS

When the cross-plane profiles from monthly QA have 1° degree difference from the commissioning profiles, it is time that the target be changed.

CONCLUSION

This method enables the clinical medical physicists to easily evaluate the target status and to help improving the quality assurance of a helical tomotherapy unit.

Tradeoffs for assuming rigid target motion in Mlc-based real time target tracking radiotherapy: a dosimetric and radiobiological analysis

We report on our assessment of two types of real time target tracking modalities for lung cancer radiotherapy namely (1) single phase propagation (SPP) where motion compensation assumes a rigid target and (2) multi-phase propagation (MPP) where motion compensation considers a deformable target. In a retrospective study involving 4DCT volumes from six (n=6) previously treated lung cancer patients, four-dimensional treatment plans representative of the delivery scenarios were generated per modality and the corresponding dose distributions were derived. The modalities were then evaluated (a) Dosimetrically for target coverage adequacy and normal tissue sparing by computing the mean GTV dose, relative conformity gradient index (CGI), mean lung dose (MLD) and lung V(2)0; (b) Radiobiologically by calculating the biological effective uniform dose (D) for the target and organs at risk (OAR) and the complication free tumor control probability (P(+)). As a reference for the comparative study, we included a 4D Static modality, which was a conventional approach to account for organ motion and involved the use of individualized motion margins. With reference to the 4D Static modality, the average percent decrease in lung V(20) and MLD were respectively (13.1-/+6.9) % and (11.4-/+ 5.6)% for the MPP modality, whereas for the SPP modality they were (9.4-/+6.2) % and (7.2-/+4.7) %. On the other hand, the CGI was observed to improve by 15.3-/+13.2 and 9.6-/+10.0 points for the MPP and SPP modalities, respectively while the mean GTV dose agreed to better than 3% difference across all the modalities. A similar trend was observed in the radiobiological analysis where the P(+) improved on average by (6.7-/+4.9) % and (4.1-/+3.6) % for the MPP and SPP modalities, respectively while the D computed for the OAR decreased on average by (6.2-/+3.6) % and (3.8-/+3.5) % for the MPP and SPP tracking modalities, respectively. The D calculated for the GTV for all the modalities was in agreement to better than 2% difference. In general, respiratory motion induces target displacement and deformation and therefore the complex MPP real time target tracking modality is the preferred. On the other hand, the SPP approach affords simplicity in implementation at the expense of failing to account for target deformation. Radiobiological and dosimetric analyses enabled us to investigate the consequences of failing to compensate for deformation and assess the impact if any on the clinical outcome. While it is not possible to draw any general conclusions on a small patient cohort, our study suggests that the two tracking modalities can lead to comparable clinical outcomes and as expected are advantageous when compared with the static conventional modality.

Impact of pulse forming network and injection current parameters on output and energy variations of helical tomotherapy

PURPOSE

In this study, an experiment was devised to establish the dependency of the impact of pulse forming network (PFN) and injection current (IC) parameters on output and energy variations of helical tomotherapy (HT) on the radiation beam output and energy.

METHODS

HT has unique radiation beam characteristics due to the absence of a flattening filter. As with conventional linear accelerators, the machine output and energy should be within a + or - 2% tolerance according to published studies. However, because a dose servo is not utilized in a HT unit, these parameters may drift out of the + or - 2% tolerance due to various reasons such as high machine temperatures. With this in mind, physicists and engineers must adjust certain machine parameters to reset the output and energy to within the tolerance of the commissioned baseline. Two parameters commonly adjusted are: PFN voltage (V(PFN)) and IC voltage (V(IC)).

RESULTS

Results showed that the HT unit possesses different working zones defined by the V(PFN) and V(IC) parameter settings. The working zones were classified into 5 zones: 1) low dose rate zone - radiation dose rate much lower than nominal dose rate and machine cannot run due to low dose rate fault; 2) normal dose rate zone - dose rate is within tolerance of nominal dose rate and machine can run without dose rate fault; 3) dose rate failure during treatment zone - dose rate within the tolerance of the nominal dose rate however machine interrupts during treatment due to dose rate fault; 4) high dose rate zone - dose rate is higher than nominal dose rate and machine cannot run due to high dose rate fault; and 5) inoperable dose rate zone - dose rate is much higher than the nominal dose rate and machine cannot run.

CONCLUSION

The results of this study may provide a quick guide for physicists to adjust their HT unit V(PFN) and V(IC) values in order to reset the radiation beam output and energy back to within the tolerance of the commissioned baseline.