High-sensitivity electronic Stark spectrometer featuring a laser-driven light source.

We report developmental details of a high-sensitivity Stark absorption spectrometer featuring a laser-driven light source. The light source exhibits intensity fluctuations of ∼0.3% over timescales ranging from 1 min to 12 h, minimal drift (≤0.1%/h), and very little 1/f noise at frequencies greater than 200 Hz, which are comparable to or better than an arc-driven light source. Additional features of the spectrometer include balanced detection with multiplex sampling, which yielded lower noise in A, and constant wavelength or wavenumber (energy) spectral bandpass modes. We achieve noise amplitudes of ∼7 × 10-4 and ∼6 × 10-6 in measurements of single A and ΔA spectra (with 92 data points) taking ∼7 and ∼19 min, respectively.

Standardized mitotic counts in breast cancer. Evaluation of the method.

Twenty-one pathologists and technicians participated in a study evaluating the variation present in mitotic counts for prognostication of breast cancer. The participants counted the mitotic figures in 20 breast cancer samples from ten high power fields (mitotic activity index, MAI, giving the results in mitotic figures per 10 fields) and also made a correction for field size and area fraction of the neoplastic epithelium to get the standardized mitotic index (volume fraction corrected mitotic index, or M/VV index, giving the result in mitotic figures per square mm of neoplastic epithelium). The difference in variation between the two methods was not big, but the standardized mitotic index (SMI) showed consistently smaller variation among all participants and different subgroups. Experienced pathologists had the highest variation in mitotic counts, and specially trained technicians, the lowest. The efficiency of the mitotic counts in grading (the grading efficiency) was used to evaluate the mitotic counts. In groups without special training for mitotic counts the mean grading efficiency was lower (experienced and training pathologists both on average had the potential to grade 88% of the cases correctly) than in the group specially trained for the purpose (trained technicians had the potential to grade 95% of the cases correctly). Among the specially trained technicians, the grading efficiency was of the same magnitude as the grading efficiency achieved in determining the S-Phase fraction of cells from paraffin embedded breast cancers by flow cytometry in different laboratories. The results suggest that special training is helpful in making mitotic counts more reproducible, and that in trained hands, the mitotic counts give results comparable to more sophisticated methods of determining proliferative activity in breast cancer.

Reproducibility of mitosis counting in 2,469 breast cancer specimens: results from the Multicenter Morphometric Mammary Carcinoma Project.

The Multicenter Morphometric Mammary Carcinoma Project is a prospective study on the reproducibility and prognostic value of routine quantitative assessments, especially the mitotic activity index (MAI), the multivariate prognostic index (MPI; a combination of MAI, tumor size, and lymph node status), the mean nuclear area, and DNA ploidy assessments in patients with invasive breast cancer. Fourteen pathology laboratories providing routine services to 35 hospitals throughout The Netherlands are participating in this project. In this article, the reproducibility of MAI and MPI assessments is described. Assessment of the MAI was, according to a strict protocol, first performed in the participating laboratories; thereafter, slides were transferred to the coordination center in Amsterdam for quality control. Analysis of the reproducibility of the assessments in 2,469 patients showed correlation coefficients between 0.81 and 0.96 (mean, 0.91) for the MAI and between 0.91 and 0.97 (mean, 0.96) for the MPI. The reproducibility was fairly constant in time, although it showed a slight drop in the middle of the 2-year intake period. A prognostically relevant discrepancy in MPI (caused by differences in MAI) between the original and quality control assessments was found in only 7.2% of the cases. When analyzing the reasons for these discrepancies, a plausible explanation could be found in all cases: bad tissue processing and ignorance of or negligence in following the protocol guidelines for selection of the counting area or in the process of counting were the most important flaws. Since these errors are largely controllable, an even lower discrepancy rate is theoretically achievable. In conclusion, in a routine setting it can be learned, within a reasonable time, to perform mitosis counting in a highly reproducible way if a strict protocol is carefully followed. This opens the way for a wider application of the MAI and MPI in breast cancer patients. Motivation is, however, an important factor to obtain reproducible results, and ongoing quality control is essential to guarantee the reproducibility of the assessments.

A comparative study in morphometric grading of transitional cell carcinoma of the urinary bladder.

To overcome the considerable observer inconsistency in the histologic grading of transitional cell carcinomas, the value of four different morphometric grading methods was investigated in 61 tumors of the bladder. Only two methods showed satisfactory reproducibility. Both methods, one based on random nuclear sampling and the other on selective nuclear sampling, showed an increase in the mean and standard deviation of the nuclear area with higher tumor grades (P less than .00001). Morphometric classification of the learning set (44 cases) was in agreement with the unequivocally assessed histologic grade in 35 cases (79.5%) using random sampling and in 38 cases (86.4%) using selective sampling. By reducing the grading classes to "low" (grades 1 and 2) and "high" (grade 3) and by introducing a classification probability threshold (0.80), an accurate morphometric classification was achieved in 38 cases (86.4%) using random sampling and in 41 cases (93.2%) using selective sampling. Of the 17 cases with histologic grading discrepancies, all 10 low-grade tumors (with discrepancies of grade 1 versus grade 2) were correctly classified as low-grade carcinomas by both of the morphometric methods; in the remaining 7 cases, with low-versus-high discrepancies (grade 2 versus grade 3), the selective method yielded better correlation with the tumor stage and clinical follow-up. It is concluded that morphometric classification is an acceptable alternative for histologic grading by pathologists, provided that the reproducibility of the method is confirmed. Although both random and selective sampling yielded satisfactory classifications, the selective method gave more reliable results as confirmed by the clinical behavior.

Data processing and analysis in the Multicenter Morphometric Mammary Carcinoma Project (MMMCP).

In the Multicenter Morphometric Mammary Carcinoma Project (MMMCP), the prognostic value and reproducibility of routinely assessed quantitative pathological parameters in breast cancer is prospectively studied in approximately 3000 patients. Considering the high number of patients and the fact that many laboratories and hospitals throughout the Netherlands participate in this project, data acquisition, processing and analysis is an important component of the project. The data collection scheme, the structure of the database and the processing of data are described.

Reproducibility of flow cytometric assessment of follicular tumours of the thyroid.

The reproducibility of the DNA index of paraffin wax sections from 44 follicular tumours of the thyroid (18 follicular adenomas and 26 follicular carcinomas), which had been assessed by flow cytometry was analysed in two laboratories, using consecutive sections of the same specimens and two different commercially available flow cytometers. Two slightly different cell preparation and staining techniques were used in the two laboratories. Using strictly defined criteria the histograms were classified blind as diploid, peritetraploid, aneuploid, or inadequate and insufficient by two independent investigators. Both the concordance between the two different flow cytometers and the agreement of duplicate assessments within the same flow cytometers were assessed. The mean coefficient of variation of the G0/G1 peak of the diploid tumours in the PARTEC flow cytometer was 5.5 (range 2.3-9.8) and in the FACS flow cytometer 5.2 (range 3.7-8.3); this difference was not significant. There was concordance of classification between the two laboratories in 35 of 36 cases. In 25 cases (18 diploid, seven aneuploid) the intralaboratory variation showed a 100% concordance in histogram classification. It is concluded that flow cytometer DNA index assessment of follicular tumours of the thyroid is reproducible and can be used to evaluate the discriminating and prognostic value of this feature.

Quantitative pathologic analysis of first and second primary cancers in double tumors of the lung.

In spite of the frequent occurrence of double tumors of the lung, pathologic reports on these tumors are rare. In this study, 34 patients with double tumors (10 metachronous and 24 synchronous) were quantitatively analyzed; in all cases, both the first and second tumors had been completely resected and had adequate archival material. One aim of the study was to investigate whether there was a difference in the malignancy of the first and second tumors, as evaluated from their pathologic features. A second question was whether the length of the disease-free interval between the first and second tumors or the survival could be predicted on the basis of any of the investigated features. It was found that the first and second tumors, whether synchronous or metachronous, were strikingly similar: there was no difference in any of the quantitative pathologic features studied (epithelial percentage, DNA index, mean nuclear area and standard deviation of the nuclear area). It was not possible to predict by either univariate or multivariate analysis from any of the parameters either the length of the disease-free interval between the first and second tumors or the survival. These quantitative pathologic similarities suggest that the malignancy of the second tumor (synchronous as well as metachronous) is not higher than that of the first tumor. Thus, in the case of metachronous tumors, the fact that most of the second tumors (60%) are detected at a higher (inoperable) stage is probably caused by inadequate follow-up and not by increased malignancy.(ABSTRACT TRUNCATED AT 250 WORDS)

The percentage of aneuploid cells is significantly correlated with survival in accurately staged patients with stage 1 resected squamous cell lung cancer and long-term follow up.

Previous studies have shown that ploidy is an important prognostic determinant in lung cancer, but in those studies followup was restricted to three years, while patients with Stage 1, 2 and 3 disease and with different histological subtypes were included. Theoretically, these factors could have influenced the findings, especially since aneuploidy strongly correlated with the stage of disease. Because of this, tumor ploidy was studied in surgically resected stage 1 (T1/2, N0M0) squamous cell lung cancer patients with a minimal followup of 6 years. All patients were accurately staged by mediastinal lymph node mapping. Fifty-two from a group of 1539 patients with lung cancer diagnosed between 1980 and 1986 inclusive, fulfilled these criteria. Of these tumors, 23 (44%) were diploid with a 6-year survival of 53% and 29 (56%) were aneuploid with a 6-year survival of 48%. Although diploidy tended to be associated with local relapse of the tumor and aneuploidy with distant metastases, the difference was not significant and neither showed a survival advantage. However, within the aneuploid tumors, there was a significant correlation between the percentage of aneuploid cells and survival, defined as event-free or time to death. Seventeen patients with a percentage of more than 10 had a worse outcome (12 died, 6 years survival 35%), than to the other 12 patients with less than 10% aneuploid cells (2 died, 6-year survival 78%) (Mantel-Cox = 6.04, P = 0.01). This implies that in patients with accurately staged and histologically proven Stage 1 squamous cell lung cancer and long-term follow up, DNA content classified as diploid and aneuploid is not a prognostic factor for survival, but the percentage of aneuploid tumor cells is correlated with the prognosis.