Key points are not available for this paper at this time.
560 Background: Adjuvant chemotherapy for breast cancer is associated with the development of secondary AML, but this risk in an older population has not been previously quantified. Methods: We queried data from the Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database for women who were diagnosed with nonmetastatic breast cancer from 1992–1999. We compared the risk of AML in patients with and without adjuvant chemotherapy (C), and by differing C regimens. The primary endpoint was a claim with an inpatient or outpatient diagnosis of AML (ICD-09 codes 205–208). Risk of AML was estimated using the method of Kaplan-Meier. Cox proportional hazards models were used to determine factors independently associated with AML. Results: 36,904 patients were included in this observational study, 4,572 who had received adjuvant C and 32,332 who had not. The median patient age was 75.3 (66.0–103.3). The median follow up was 63 months (13–132). Patients who received C were significantly younger, had more advanced stage disease, and had lower comorbidity scores (p0.05. An analysis was performed among women who received C. When compared to other C regimens, anthracycline-based therapy (A) conveyed a significantly higher hazard for AML HR 2.17 (1.08–4.38), while patients who received A plus taxanes (T) did not have a significant increase in risk HR1.29 (0.44–3.82) nor did patients who received T with some other C HR 1.50 (0.34–6.67). Another significant independent predictor of AML included GCSF use HR 2.21 (1.14–4.25). In addition, increasing A dose was associated with higher risk of AML (p<0.05). Conclusions: There is a small but real increase in AML after adjuvant chemotherapy for breast cancer in older women. The risk appears to be highest from A-based regimens, most of which also contained cyclophosphamide, and may be dose-dependent. T do not appear to increase risk. The role of GCSF should be further explored. No significant financial relationships to disclose.
Patt et al. (Tue,) studied this question.