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In soft tissue sarcoma, the prognostic importance of DNA ploidy status is limited. One possible explanation may be technical; small nondiploid stemlines will he diluted in relation to the presence of normal diploid cells and may not be detected by flow cytometry (FCM). We assessed DNA ploidy status in 93 tumors with both FCM and image cytometry (ICM). ICM may permit the exclusion of nonrelevant cells. The ability of the two methods to detect nondiploid stemlines was compared, as were the prognostic consequences. The patients (54 males) had a median age of 69 years. Surgical procedures were performed on all patients. None of the patients had received preoperative radiotherapy or chemotherapy. FCM and ICM were performed with standard methods. The prognostic value was assessed with univariate and multivariate analysis. In 82 of the 93 tumors, a concordant ploidy status by FCM and ICM was found. In 5 FCM type 1-2 tumors (diploid), the identification of nondiploid stemlines by ICM did not influence the metastatic rates. Increasing tumor size, histotype other than liposarcoma, increasing malignancy grade, tumor necrosis, and ICM nondiploidy were univariate prognostic factors for metastasis. In a multivariate analysis, only tumor size larger than 9 cm was a prognostic factor. In about 10% of the tumors, a discrepancy between FCM and ICM ploidy status was found, but we could not find a consistent prognostic consequence of this. Neither FCM nor ICM ploidy status was an independent prognostic factor. (C) 2002 Wiley-Liss, Inc. (Less)

S-phase fraction (SPF), estimated in the flow cytometric DNA histogram, is a prognostic factor in breast cancer. There are, however, some inherent difficulties in the estimation of SPF, such as the influence of debris, aggregates, and normal cells. Most of the available SPF calculation principles try to consider these difficulties, but so far no consensus has been reached with regard to which principle is to be recommended. The aim of the present study was to investigate the prognostic impact of SPF when estimated with different calculation methods in frozen breast cancer samples from 350 patients. Two nonparametric (Rman, Rmin/both rectangle) and three parametric (ACAS/DNA-base, ModFit, and MultiCycle) calculation methods, with and without correction for debris and aggregates, were used. The mean values for SPF varied from 4.3% (ACAS/DNA-base with correction for debris and aggregates) to 9.4% (MultiCycle without any correction for background). The pairwise correlation between methods varied considerably (R = 0.72-0.98). After categorization of SPF values into low SPF (lower two tertiles) and high SPF (upper tertile), all methods yielded statistically significant Pvalues for recurrence-free survival (median follow-up time 67 months), both univariately (0.0004-< 0.0001) and multivariately (0.048-0.0004), after adjusting for nodal status, tumor size, and estrogen receptor status. SPF with background correction did not yield lower P values than SPF without. Regardless of which method was used, SPF showed similar correlations with lymph node involvement, tumor size, and estrogen receptor content. In conclusion, as the mean value of SPF for different calculation methods varies, each laboratory must be restricted to use only one method. Background correction does not seem to improve the prognostic impact of SPF in DNA histograms. Based on the experiences obtained in the present study, S-phase calculation methods without background correction may therefore be the most suitable for routine evaluation of DNA histograms of fresh frozen breast cancer material (ModFit, MultiCycle, and Rman [the latter only for experienced operators]). The nonparametric Rmin, with an automatic setting of the region used for SPF calculation, may be an alternative, but suffers from the disadvantage of not being commercially available yet.

Flow cytometric assessments of DNA ploidy status and the S-phase fraction (SPF) have been shown to yield prognostic information in breast cancer. The aim of the present investigation was to elucidate the reproducibility of results with regard to tumor DNA heterogeneity, and to ascertain whether the prognostic value of DNA measurements might be enhanced by analyzing two pieces of a tumor instead of one. Agreement with regard to ploidy status (diploid versus non-diploid) was obtained in 90% of cases (71/79) when two adjacent sections of the tumor were investigated, and in 77% of cases (10/13) when four biopsies from different quadrants of the tumor specimen were investigated. The corresponding figures for agreement in SPF (divided into three categories, less than 7.0%, 7.0-11.9%, and greater than or equal to 12%) were 75% (59/79; 2-sample series) and 55% (7/13; 4-biopsy series). The main reason for variance in ploidy results was the difficulties in distinguishing near diploid cell populations. Discrepancies in SPF categories could be explained by minor fluctuations in SPF values near the cut-off levels, or by variance in ploidy status, the fraction of non-diploid nuclei, and background noise due to cell debris. There was a stepwise increase in recurrence rate (RR) among patients with increasing SPF category (RR: 20%, 41%, and 53%). Patients whose SPF categories varied, from low or intermediate in one part of the tumor to high in another, seemed to have a poor prognosis (RR = 57%).(ABSTRACT TRUNCATED AT 250 WORDS)

In soft tissue sarcoma, the prognostic importance of DNA ploidy status is limited. One possible explanation may be technical; small non-diploid stemlines will be diluted in relation to the presence of normal diploid cells and may not be detected by flow cytometry (FCM). We assessed DNA ploidy status in 93 tumors with both FCM and image cytometry (ICM). ICM may permit the exclusion of non-relevant cells. The ability of the two methods to detect non-diploid stemlines was compared, as were the prognostic consequences. The patients (54 males) had a median age of 69 years. Surgical procedures were performed on all patients. None of the patients had received preoperative radiotherapy or chemotherapy. FCM and ICM were performed with standard methods. The prognostic value was assessed with univariate and multivariate analysis. In 82 of the 93 tumors, a concordant ploidy status by FCM and ICM was found. In 5 FCM type 1-2 tumors (diploid), the identification of non-diploid stemlines by ICM did not influence the metastatic rates. Increasing tumor size, histotype other than liposarcoma, increasing malignancy grade, tumor necrosis, and ICM non-diploidy were univariate prognostic factors for metastasis. In a multivariate analysis, only tumor size larger than 9 cm was a prognostic factor. In about 10% of the tumors, a discrepancy between FCM and ICM ploidy status was found, but we could not find a consistent prognostic consequence of this. Neither FCM nor ICM ploidy status was an independent prognostic factor.

Flow cytometric (FCM) DNA analysis yields information on ploidy status and the S-phase fraction (SPF), variables of prognostic importance in breast cancer. The clinical value of the SPF is currently being evaluated in prospective randomized trials. The widespread use of FCM DNA analysis emphasizes the importance of reproducibility (both intra- and interlaboratory). In this study, 67 nuclear suspensions of breast cancer samples were analyzed by 12 laboratories routinely performing FCM DNA analysis in breast cancer. No general guidelines were imposed; each laboratory used its own standard protocols. For DNA ploidy status (diploid vs. non-diploid), agreement was complete for 79% (53/67) of the samples, compared with 64% (43/67) of samples when tetraploidy was considered [i.e., euploid (diploid+tetraploid) vs. aneuploid (the remaining non-diploid)]. For the SPF, pairwise comparison of the results of all 12 laboratories yielded a mean Spearman's rank correlation of 0.78 (range: 0.54-0.93). For those 39 samples being categorized in low or high SPF by all laboratories, all agreed in 14 samples (36%). Similar patterns were obtained with kappa measures, agreement being good for ploidy status (diploid vs. non-diploid; overall kappa = 0.87 and 0.74 for euploid vs. aneuploid), but moderate for the SPF [overall kappa = 0.47 (for low SPF vs. high SPF vs. "no SPF reported")]. Discrepancies were chiefly attributable to differences in the categorization of the S-phase values, rather than in FCM procedures, other critical differences being in the detection and interpretation of near-diploid and small non-diploid cell populations, the definition of tetraploidy, and the choice and execution of the method used for S-phase estimation. Based on the observations of this study, detailed guidelines for FCM analysis and interpretation of data are proposed in the Appendix. Some issues remain, however, e.g., to standardize a method for S-phase calculation and tetraploid definition.

Measurements of DNA ploidy can be performed either with image cytometry (ICM) or flow cytometry (FCM); both methods provide independent prognostic information in primary breast cancer. The aim of the present investigation was to compare the two methods and to relate the findings to prognosis (median follow-up 42 months). Concordance in ploidy status (diploid, tetraploid, aneuploid) was obtained in 76% of the samples (168/222). When the fraction of S-phase cells (SPF) from FCM analysis was also taken into consideration, four different groups of samples were obtained (Flow I-IV), which were considered to correspond to the Auer classification (Auer I-IV) of DNA histograms obtained from image cytometry. Complete concordance between the two techniques now was 70% (155/222). Samples classified as Flow I (diploid or near-diploid with low SPF) and Auer I had a distant metastasis rate of 3/60 (5%), as compared to 62/154 (40%) for all other combinations of the Flow and Auer classifications taken together. Thus, the only findings of prognostic importance were that some samples were Flow I but not Auer I, or vice versa. These two groups represent 17 (7.7%) and 14 (6.3%), respectively, of the total number of samples, and had frequencies of distant metastasis similar to those of the other high-risk groups, namely, 7/17 and 5/14, respectively. In a multivariate analysis, flow cytometric S-phase value was a stronger prognostic factor than either the Flow and Auer classification. We conclude that when routine FCM DNA analysis is used, diploid or near-diploid samples with a low S-phase value should be reanalyzed with ICM.