Published in Cancer Detection and Prevention 2000; 24(Supplement 1).

Study of chromosome damage in patients with breast cancer submitted to the two antineoplastic treatments

LM Silva MSc 1, CS Takahashi PhD 2, HHB Carrara MD 3

1 Dept Genetics,, 3 Dept Gynecology and Obstetrics, Faculty of Medicine of Ribeirão Preto;, 2 Faculty of Philosophy, Sciences, and Letters of Ribeirão Preto; São Paulo University, São Paulo, Brasil,

AIMS: Most of the antineoplastic drugs induce DNA damage leading to chromosomal aberrations (CAs) and point mutations. METHODS: The frequency of CAs in peripheral blood lymphocyte cultures from women with breast cancer submitted to chemotherapy (CT) were determined in 15 and 18 patients respectively submitted to the FEC (5-fluorouracil, epirubicin and cyclophosphamide) and CMF (cyclophosphamide, methotrexate and 5-fluorouracil) cocktail in six CT cycles, although in each CT cycle the number of patients varied from 1 to 3 for sister chromatid exchanges (SCEs) and from 2 to 5 for CAs. Samples were collected before and 48 h after CT. After treatment with the FEC cocktail, CA frequencies increased after each CT cycle but only temporarily, being followed by a reduction that persisted until the next CT cycle (21 days). RESULTS: The CMF cocktail did not show a clear reduction in CA frequencies between CT cycles, and the FEC cocktail induced a better cell recovery than the CMF. SCE analysis was more sensitive than CA analysis. Despite wide interindividual variability, the frequencies before CT were similar in all cycles of treatment with both cocktails. Proliferative index values were unchanged in the samples collected after CT compared to those collected before CT for both cocktails. CONCLUSIONS: Although the size of the present sample was limited and interindividual variability was wide, it appears that a 21 day interval between CT sessions is sufficient for cell recovery. This fact was demonstrated by the reduction in CA and SCE frequencies between cycles in parallel to the unchanged mitotic index values.

KEY WORDS: Chemotherapy, Breast Cancer, Chromosome Aberrations, Sister Chromatid Exchanges.

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Paper presented at the International Symposium on Impact of Biotechnology on Cancer Diagnostic & Prognostic Indicators; Geneva, Switzerland; October 28 - 31, 2000; in the section on chemotherapy.