Tumor size and disease progression are not always related

Vancouver (September 12h, 2003) - A team of researchers led by Drs. William Foulkes and Steven Narod, investigators of the Canadian Genetic Diseases Network, has made an important discovery about differing patterns of metastasis in women with breast cancer.

Traditionally, it was believed that the larger a tumor in a breast cancer patient, the more likely it was that the cancer cells had metastasized into the lymph system. The results of the study, which will be published in the October 15th 2003 issue of CANCER, demonstrate that the tumor size in a breast cancer patient with the BRCA1 gene mutation is not necessarily correlated with local disease progression.

"This discovery is important because it points to the fact that breast cancer is many diseases," said Dr. Foulkes. "Until each sub-type of breast cancer is understood, including hereditary and acquired forms of the disease, data from whole populations should not be used to predict disease behavior, such as metastatic potential, response to treatment and survival. Hereditary and acquired forms of breast cancer have biological differences that may require different diagnostics and treatments."

"Breast cancer affects one in nine women," said Dr. Michael Hayden, Scientific Director of the Canadian Genetic Diseases Network. "This discovery has the potential to significantly affect the prognoses of women diagnosed with this life-threatening disease."

Dr. Foulkes is an Associate Professor in the Departments of Medicine, Human Genetics and Oncology at McGill University, and directs the Program in Cancer Genetics at McGill. Dr. Narod is the Canada Research Chair in Breast Cancer and a scientist at the Centre for Research on Women's Health, Women's College Hospital, University of Toronto. This study was funded by the Canadian Genetic Disease Network, the Fonds de la Recherche en Sant� du Qu�bec Cancer Network - Breast and Ovarian Tumour Bank Axis, the Susan G. Komen Foundation, Norwegian Cancer Society and the Norwegian Research Council.