In an effort to determine whether surgery helps to spread remnant breast cancer cells, particularly cells that overexpress HER2, Italian researchers compared histologic sections of primary breast cancers with specimens of re-excised residual tumors obtained within 48 days of the first surgery.
While the investigators found no overall change in tumor proliferation between initial and repeat surgeries, a subset of specimens that overexpressed HER2 displayed a 10% increase in proliferative cells upon re-excision.
In addition, the researchers found that wound drainage fluid and postsurgical serum samples contain growth factors that stimulate proliferation of HER2-positive breast carcinomas. This finding, they suggest, helps to explain why HER2 expression is associated with a poor prognosis and why invasive diagnostic procedures often lead to increased residual tumor growth with other types of cancer.
Lastly, the investigators determined that treatment of HER2-positive tumor cells with trastuzumab abolished drainage fluid-induced proliferation, suggesting a potential therapeutic role for this and other monoclonal antibodies in pre-, peri-, and postoperative settings.
Tagliabue E, Agresti R, Carcangiu L, et al. Role of HER2 in wound-induced breast carcinoma proliferation. Lancet. 2003;362:527-533.