Prognostic factors and natural history in lymph node-negative breast cancer patients.

The prognostic significance of clinical and histological factors as well as hormone receptors was analyzed in a population of 3,064 lymph node-negative breast cancer patients operated in the Stockholm region between 1976 and 1988. None of these patients received systemic adjuvant treatment. Multivariate analysis showed that only histological tumor size, number of examined axillary lymph nodes, and progesterone receptors were independent prognostic factors in terms of recurrence-free interval. An individual risk of recurrence was calculated taking into account these three factors to discriminate between three groups of patients with a risk of less than 15%, 15-25%, and more than 25% of recurrence at 5 years. Similar results were obtained taking into account only the first two factors. The prognostic information added by the knowledge of progesterone receptors only changed the recurrence rate in approximately 3%. This study showed that conventional prognostic factors permit the identification of high risk lymph node-negative breast cancer patients. Results obtained by the use of new more sophisticated factors should be compared with those obtained analyzing strong conventional prognostic factors.