The effect of prior adjuvant chemotherapy on survival in metastatic breast cancer

Some adjuvantly treated patients develop recurrent breast cancer and little is known about the effect of prior adjuvant chemotherapy on subsequent response rates to systemic therapy or on overall survival. We describe our retrospective comparison of 179 patients who received doxorubicin containing adjuvant chemotherapy and developed recurrent breast cancer on University of Arizona Cancer Center clinical trials with 202 non-adjuvantly treated patients entered onto clinical protocols for recurrent or metastatic breast cancer during the same period. Adjuvant failures had a shorter median survival from the date of onset of recurrent disease (18 months versus 28 months, P less than 0.001), a lower response rate to initial combination chemotherapy (38% versus 69%, P = 0.001), and a high incidence of CNS involvement at the time of relapse (11%). In patients having recurrent or metastatic breast cancer, a history of prior adjuvant chemotherapy appears to identify a subgroup who will have a higher incidence of CNS involvement, a lower response rate to chemotherapy and a shorter survival with metastatic disease. These findings may help explain the failure of improved relapse free survival seen in many adjuvant chemotherapy trials to result in improved overall survival.