NEW YORK—Treatment of metastatic breast cancer is "a book with many chapters, ie, with many opportunities for meaningful intervention, as opposed to pancreatic cancer, for example," Andrew Seidman, MD, said in his discussion of metastatic breast cancer at the Second Annual Advances in Oncology meeting, sponsored by the journal ONCOLOGY.
The most frequently used treatment strategies include combination chemotherapy, dose-intense or dose-dense regimens, and the incorporation of rationally designed, targeted, biologic therapies into treatment protocols.
These strategies are supported by data from phase III clinical trials and meta-analyses, and represent an attempt to approach the care of the patient from the perspective of "evidence-based" medicine, said Dr. Seidman, associate attending physician, Breast Cancer Medicine Service, Memorial Sloan-Kettering Cancer Center. However, "this is not the whole story," he said, emphasizing that clinicians must consider treatment toxicities and effects on overall survival.
Dr. Seidman ascribes the enthusiasm for combination regimens to "the reports of objective responses and a certain comfort level with combinations in the treatment of other solid tumors," and questions whether A plus B is better than A followed by B.
He cited at least seven randomized comparisons of combination chemotherapy regimens (anthracyclines and nonanthracyclines) vs monotherapy for metastatic breast cancer that showed no survival advantage for the combination as well as significantly higher hematologic and nonhematologic adverse events.
These protocols (Sledge: J Clin Oncol, 2003; Joensuu: J Clin Oncol, 1998; Nabholtz: J Clin Oncol, 1999; Bishop: J Clin Oncol, 1999; Heidemann: Ann Oncol, 2002; Norris: J Clin Oncol, 2000; and Ejlertsen: J Clin Oncol, 2004), with a combined population of 2,490 patients "challenge the role of combination chemotherapy as the gold standard in the treatment of metastatic breast cancer," he said.
Dr. Seidman said he leans toward using single agents sequentially until disease progression or intolerable toxicity, then switching to another single agent or to a combination. "The heterogeneity of the biology of breast cancer argues strongly for flexibility in treatment," he commented.