Lactate dehydrogenase as a prognostic factor for survival time of terminally ill cancer patients: A preliminary study

Construction of a new, objective prognostic score for terminally ill cancer patients: a multicenter study

GOALS OF WORK

The goal of this study was to develop a new, objective prognostic score (OPS) for terminally ill cancer patients based on an integrated model that includes novel objective prognostic factors.

MATERIALS AND METHODS

A multicenter study of 209 terminally ill cancer patients from six training hospitals in Korea were prospectively followed until death. The Cox proportional hazard model was used to adjust for the influence of clinical and laboratory variables on survival time. The OPS was calculated from the sum of partial scores obtained from seven significant predictors determined by the final model. The partial score was based on the hazard ratio of each predictor. The accuracy of the OPS was evaluated.

MAIN RESULTS

The overall median survival was 26 days. On the multivariate analysis, reduced oral intake, resting dyspnea, low performance status, leukocytosis, elevated bilirubin, elevated creatinine, and elevated lactate dehydrogenase (LDH) were identified as poor prognostic factors. The range of OPS was from 0.0 to 7.0. For the above cutoff point of 3.0, the 3-week prediction sensitivity was 74.7%, the specificity was 76.5%, and the overall accuracy was 75.5%.

CONCLUSIONS

We developed the new OPS, without clinician's survival estimates but including a new prognostic factor (LDH). This new instrument demonstrated accurate prediction of the 3-week survival. The OPS had acceptable accuracy in this study population (training set). Further validation is required on an independent population (testing set).

Clinical pathology differences in laboratory utilization in hospice and nonhospice units

A significant difference can be observed between hospice and nonhospice philosophy. Nonhospice units direct its effort to cure and sustain patient's life using disease-modifying therapeutic procedures, while hospice units focus on patient's quality of life. However, despite the differences between the 2 basic philosophies in question, both approaches share 1 aspect in common: the correct diagnosis of the patient. In any case above, laboratory analysis is a valuable tool. This work aims to compare the laboratory utilization between nonhospice cancer and hospice cancer units. Laboratory requests from patients within a 1-year period were evaluated and the hospice laboratory profile was presented. We demonstrated that nonhospice unit had a major volume of requested laboratory test than hospice unit, but for inpatients this difference was not so dramatic.

New prognostic index to predict survival in patients with cancer of unknown primary site with unfavourable prognosis

AIMS

To identify independent prognostic factors in patients with cancer of unknown primary site (CUP) who do not belong to prognostically favourable subsets, and to develop a prognostic index for predicting survival in these patients.

MATERIALS AND METHODS

In this prospective study, univariate and multivariate analyses of prognostic factors were conducted in a population of 145 patients with CUP in two clinical institutions. Subsets of patients with favourable prognostic features and those requiring well-defined treatment were excluded.

RESULTS

The 1-year overall survival rate for all patients was 42% and the median overall survival was 330 days. Overall survival was significantly related to the following pre-treatment prognostic factors: poor Eastern Cooperative Oncology Group performance status (ECOG PS)>or=2, presence of liver metastasis, elevated serum lactate dehydrogenase (LDH), high white blood cell count, anaemia, age>or=63 years, and prolonged QTc interval in electrocardiography (ECG). In multivariate analysis, four independent adverse prognostic parameters were retained: elevated LDH (hazard ratio 2.21; 95% confidence interval 1.41-3.47; P=0.001), prolonged QTc interval (hazard ratio 2.10; 95% confidence interval 1.28-3.44; P=0.003), liver metastasis (hazard ratio 1.77; 95% confidence interval 1.11-2.81; P=0.016) and ECOG PS>or=2 (hazard ratio 1.69; 95% confidence interval 1.05-2.73; P=0.03). We developed a prognostic index for overall survival based on the following subgroups: good prognosis (no or one adverse factor), intermediate prognosis (two adverse factors) and poor prognosis (three or four adverse factors). The median overall survival for the three subgroups was 420, 152 and 60 days, respectively, P<0.0001.

CONCLUSIONS

This study validated previously identified important prognostic factors for survival in patients with CUP. Prolonged QTc was additionally identified as a strong adverse prognostic factor. We developed a simple prognostic index using performance status, LDH, presence of liver metastasis and QTc interval in ECG, which allowed assignment of patients into three subgroups with divergent outcome.

Commutable Calibrator with Value Assigned by the IFCC Reference Procedure to Harmonize Serum Lactate Dehydrogenase Activity Results Measured by 2 Different Methods

Background: The availability of commutable calibrator materials may ease considerably the task of harmonizing assay results and ensuring their traceability to reference procedures. We sought to verify the commutability of potential calibrator materials and evaluate their effectiveness in harmonizing LDH results by 2 measurement methods.

Methods: We measured LDH in 109 serum samples and 31 materials, including frozen serum pools (with either normal or abnormal isoenzyme patterns), commercial stabilized materials, and the ERM-AD453/IFCC reference material. We assayed LDH activity with the IFCC reference procedure and with 2 commercial methods, 1 using the lactate-to-pyruvate (LP) reaction, and the other the pyruvate-to-lactate (PL) reaction. We selected a commutable material, with LDH value assigned by the reference procedure, as a calibrator for recalculating the results for patient sera by both LP and PL, thereby making them traceable to the IFCC reference procedure.

Results: Original values for patient sera (n = 109) by the 2 commercial methods showed a mean (SD) PL/LP ratio of 1.97 (0.03); this ratio changed to 1.06 (0.02) after recalculation of results. Linear regression of PL vs LP recalibrated values gave y = 1.108x – 9.7. At the clinically important concentration of 250 U/L (upper reference limit), the systematic difference between methods was 6.8%, which met our proposed quality specifications for inaccuracy and total error.

Conclusions: By properly selecting the calibrator, the results of serum LDH measurement by 2 different methods may be harmonized and made traceable to the selected highest (reference) metrological level.