The paper of Yuan and colleagues (Br JSurg 1991; 78: 844-8) purports to show the long-term prognostic value of DNA ploidy in node-negative breast cancer.
Much of the paper describes data for both node-positive and node-negative patients; of the four figures and three tables, only one (Figure31 illustrates the prognostic value of DNA ploidy in node-negative patients. Of 170 patients studied, 120 were node-negative. This too is confusing, as in most unbiased series of this size, this proportion of node-negative patients is unduly high. Surgery is said to be principally mastectomy with node sampling; did all patients have adequate node sampling?
The authors make the point that the relative prognostic importance of variables is best assessed in multivariate analysis; yet no such multivariate analyses are shown for node-negative patients alone. N o account is given in the discussion of the conflicting findings of other authors who have similarly assessed the potential value of DNA ploidy in node-negative women'-3. In a multivariate analysis of 368 node-negative patients treated in this unit (median follow-up 8 years) neither DNA ploidy nor c-erbB2 were of independent prognostic value additional to histological grade or tumour size. In the analysis DNA ploidy, c-erbB2, menopausal status, tumour size and histological grade were entered. As Yuan found, DNA diploidy/aneuploidy was of prognostic significance in univariate analysis ( P = 0.002).
The authors comment that identification of women with potentially poor outcome from within good prognostic groups is difficult. What is required is a pathologist who carefully measures tumour size and assesses histological grade or morphological type.