Feasibility of thymidine labelling index on fine needle aspirates from breast cancer: comparison with surgical samples.

Fine-needle aspiration (FNA) provides a suitable diagnostic tool in the management of patients with breast cancer lesions. The current study reports on tumor proliferative activity, by 3H-Thymidine Labelling Index (TLI), assessed on 59 FNA (TLI1) and 28 surgical specimens (TLI2) from the same breast cancer patients. Median TLI values from FNA and surgical material were 1.0% and 0.7%, respectively. In the 28 patients, evaluable for the comparison between TLI1 and TLI2, the association was found to be highly significant (p = 0.000). Moreover, no change in tumor proliferative activity was observed in the majority (79%) of cases when evaluated preoperatively and at surgery. This study confirms the feasibility of TLI analysis on FNA from breast cancer and provides results superimposable on those obtained in a tissue sample from the same patient.