DNA flow cytometry does not predict 5-or 10-year recurrence rates for T1-2node-negative breast cancer

Background: A small proportion of T1 or T2 node-negative breast cancer tumo rs will recur in patients by 5 years, and more by 10 years. Results of rece nt studies have suggested improvement in overall survival with administrati on of adjuvant chemotherapy to all patients. More sensitive and specific me thods are needed to identify patients at highest risk for recurrence who mi ght benefit most from adjuvant therapy, saving others from unnecessary trea tment. Some investigators have suggested DNA flow cytometry as a method to discriminate patients at greatest risk for recurrence. Hypothesis: DNA flow cytometry has predictive value for breast cancer recur rence in node-negative patients. Methods: The cancer registry of a medium-sized university-affiliated hospit al was used to identify patients with T1-2 NO MO breast cancer treated with a uniform surgical approach and no adjuvant therapy who had completed at l east 5 years of follow-up or had recurrence. Flow cytometric analysis was p erformed on paraffin-embedded specimens. Results: Of 115 patients, 92 (80%) had disease-free survival without recurr ence and 23 (20%) had recurrence. Comparison of diploid and nondiploid tumo rs for likelihood of recurrence revealed no association (P=.79). Furthermor e, the DNA index and S-phase fraction were not significantly different betw een recurrent and nonrecurrent groups. Conclusions: The likelihood of recurrence of small node-negative breast can cers after mastectomy cannot be accurately predicted on the basis of DNA fl ow cytometric analysis. Traditional methods for determining risks-such as n uclear and histological grade, lymph node status, and tumor size-seem to be more useful. Sentinel lymph node biopsy techniques may increase the detect ion of micrometastases.