51. Biological concepts of breast cancer: implications for therapy

Abstract

The data from over 3000 breast cancer patients treated without adjuvant chemotherapy and followed-up for over 15 years were studied with two aims:

• 1)

  to analyze the relationship between tumor diameter and incidence of distant metastases during the 25 years after initial treatment. The threshold volume at which dissemination occurs can be estimated in each subset of patients and varies widely; it is inversely correlated with the histologic grade and the number of involved axillary nodes.

• 2)

  to investigate the impact of a residual tumor on distant dissemination. In patients with local recurrence, the incidence of distant dissemination is elevated. The analysis of the delay between the initial treatment and clinical emergence of the metastases shows that the excess of metastases corresponds to disseminations which are initiated after initial treatment and therefore originated from the residual tumor.

This conclusion was supported by the update of s controlled clinical trial comparing two adjuvant treatments: A) a chemotherapy by CMF or B) post-operative radiotherapy (RT) followed by immunothcrapy with poly A – poly U. At 15 years the cumulative incidence of local recurrence and of distant metastases is significantly lower in the B group (42% metastasis-free survival in the RT group and 29% in the CT group p=0.03). This result seems to be due mostly to lower incidence of local recurrence.