Estimating survival rates after ovarian cancer among women tested for BRCA1 and BRCA2 mutations.

Several studies have reported that women with ovarian cancer and a BRCA1 or BRCA2 mutations have better survival than women with ovarian cancer and no mutation. Potential reasons for this include possible differences in histologic subtype, stage, grade and response to chemotherapy, but some of the difference in survival may be due to systematic bias, i.e. a difference in survival rates for women who do and who do not undergo genetic testing. We estimated the survival rate in 1423 ovarian cancer patients from Ontario who had genetic testing and compared this with the survival rate for all 3367 ovarian cancer patients from the province from whom the tested sample was derived. Tested women had a 10-year survival of 54.5%, compared to 35.8% for all patients in the province. We evaluated the extent to which three different methods of adjustment eliminated the observed difference. The adjusted rates for the tested cohort were closer to the provincial average, but each adjustment method resulted in a modest over-estimate of 10-year survival, ranging from 6.1% to 10.0%. The mortality advantage for tested women was due, in part, to a lower than expected mortality rate of tested women in the period following genetic testing.

The IRMM--International Measurement Evaluation Program (IMEP). IMEP-3--trace elements in synthetic and natural water.

The aim of the IRMM--International Measurement Evaluation Program (IMEP) is to test out a possible realization of international measurement comparability for field laboratories through traceability of their measurements to the SI Unit for amount of substance: the mole. In IMEP-3, 10 different trace elements, B, Ca, Cd, Cu, Fe, K, Li, Pb, Rb, and Zn, were determined in a synthetic and a natural water by participating laboratories using their routine methods and graphically compared (in coded form) to certified values, established by IRMM and NIST using an isotope-specific method (Isotope Dilution Mass Spectrometry, Neutron Activation Analysis). The number of participants was 70; 64 laboratories have reported results. The results show a spread of more than 50% asymmetrically around the certified value. The Youden graphs allow evaluation of the overall performance of the laboratories in the IMEP-3 round.

Purified reagents for trace metal analysis.

Sub-boiling distillations have become a standard tool for the reduction of the inorganic analytical blank. More than 10 years of practical experience in the production of reagent acids is reviewed and a description is given of a new laboratory especially designed to permit trouble-free operation as well as ensure the continued high quality of the reagents produced.