Chromosomal abnormalities in women with breast cancer after autologous stem cell transplantation are infrequent and may not predict development of therapy-related leukemia or myelodysplastic syndrome

We determined prospectively the incidence of chromosomal abnormalities in p atients with high-risk breast cancer (HRBC) after high-dose chemotherapy (H DCT) and autologous stem cell transplantation (ASCT), and correlated the cy togenetic abnormalities with the development of post-transplant myelodyspla stic syndrome or acute myeloid leukemia (MDS/AML). From 1990 to 1999, 229 w omen with HRBC under went ASCT. Cytogenetic analysis of bone marrow (BM) ce lls was performed 12-59 months after ASCT in 60 consecutive women uniformly treated with sis courses of FAC/FEC followed by HDCT and ASCT, With a medi an followup of 36 months after ASCT, there were no cases of MDS/AML, among the 229 patients. In the selected cohort of 60 patients, three (5%) showed clonal chromosomal abnormalities (two single trisomy X and one t(1;6)), whe reas two additional patients showed nonclonal reciprocal translocations. Tw o of the patients with clonal aberrations had blood cytopenias as well as s ubtle dysplastic pictures in BM which were not classifiable as MDS accordin g to the FAB criteria. Similar dysplastic features were also observed in fo ur patients with normal karyotypes. All cytogenetic aberrations were transi ent and disappeared, except a + X detected by FISH in a residual cell popul ation in one of the patients. Retrospective cytogenetic and FISH studies of samples obtained after sis cycles of FAC/FEC and before transplant demonst rated no chromosomal abnormalities in any of the five patients with post-AS CT karyotypic changes. Early changes in karyotype detected in breast cancer patients following ASCT are transient and do not correlate with or predict development of MDS/AML. As these aberrations were not present before ASCT, they may be related to the HDCT regimen or transplant procedure rather tha n to the prior adjuvant therapy. Our results suggest that ASCT may be less likely to cause MDS or AML in breast cancer patients as compared to other m alignancies.