Adjuvant therapy reduces the benefit of palliative treatment in disseminated breast cancer - own findings and review of the literature.

BACKGROUND: Adjuvant treatment concepts have improved the 10-year cure rate of breast and colon cancer, but new treatments for metastatic disease have yielded only incremental benefit. If treatments for disseminated cancer were actually prolonging life rather than only increasing remission rates, this effect should have been documented over the last 30+ years. However, published data concerning advances in treatment for disseminated cancer have been contradictory. PATIENTS AND METHODS: To add data-based information, we analyzed 2 sources: a regional population-based cancer registry (Hamburgisches Krebsregister, HKR), and a research cancer registry (Projektgruppe Internistische Onkologie, PIO). We compared the survival of several thousand patients with metastatic disease who received treatment only after dissemination with that of patients who received initial adjuvant therapy. RESULTS: After adjuvant treatment, survival in patients with disseminated breast cancer is up to a third shorter than that of patients without adjuvant therapy. CONCLUSIONS: In accordance with published evidence, we conclude that ineffective adjuvant treatment shortens survival after documentation of metastatic disease. This is probably due to the elimination of chemo-sensitive tumor cells or to the induction of resistance in remaining micrometatases. This negative effect on survival after dissemination has been shown clearly for breast cancer and is also probable for cancer of the colon and other sites.