The primacy of tumor size as a prognostic factor in node-negative breast cancers

Retrospective studies have found that ploidy and S phase have significant prognostic value for node-negative breast cancer patients independent of tumor size. These findings have not been corroborated by prospective studies possibly because retrospective studies inappropriately analyzed tumor size categorically and ignored significant correlations between tumor size and ploidy and S phase, and because of poorer quality assays performed on paraffin-embedded tissue. We prospectively studied the relationship between serum markers, proliferative indices, oncoprotein expression, receptors, stage of disease, and tumor size in breast cancer patients. Preoperatively serum from 148 consecutive node-negative patients with malignant biopsies was assayed for serum markers: lipid-associated sialic acid (LASA-P), CA15-3, and carcino-embryonic antigen (CEA). DNA ploidy, % S phase, Ki-67 nuclear antigen, estrogen (ER) and progesterone (PR) receptors, epidermal growth factor receptor (EGFR), and HER-2/neu (H2N) oncogene expression were measured on frozen tissue obtained at biopsy. Correlation coefficients were statistically significant for the relationships between tumor size and S-phase fraction, ploidy, and CA15-3. No relationship was found between tumor size and age, or age at menarche, menopause, first pregnancy, or first birth. Tumor size was related to number of pregnancies, and number of live births. The strong correlation between tumor size and prognostic markers supports the hypothesis that the most significant prognostic factor for node-negative breast cancer patients is tumor size.