NEW YORK, Jan 04 (Reuters Health)
Cancer Information and Support International
By counting the number of lymph nodes under a woman's arm after surgery to remove a breast tumor, doctors can predict her risk of dying from breast cancer in the next 5 years, even when there is no evidence that the cancer has spread to the nodes, US researchers report.
Their study in the January issue of the journal Cancer is the first to demonstrate the importance of total number of lymph nodes to survival in breast cancer patients.
Doctors currently gauge survival after breast cancer surgery by counting the number of axillary (armpit) lymph nodes to which cancer has spread. However, about 10% to 15% of women will die from the spread of cancer when there appears to be no axillary lymph node involvement.
``In women with no evidence that cancer has spread, a major problem is that we don't have a good indicator of which women will ultimately die of metastatic breast cancer,'' lead author Dr. Robert L. Camp, a post-doctoral fellow in the department of pathology at the Yale University School of Medicine in New Haven, Connecticut, told Reuters Health.
``Our study indicates that a high number of axillary lymph nodes in patients with lymph node negative breast carcinoma is of significant predictive value in determining patient survival,'' the research team concludes.
Camp said there is actually little variation in the total number of lymph nodes between women. However, more aggressive tumors cause lymph nodes to swell, giving the appearance that more exist.
The investigators found that ``the 5-year survival rate for patients with 20 or more tumor-free lymph nodes was 84.7%, compared with 96.3% for patients with fewer than 20 tumor-free lymph nodes.''
Camp and colleagues looked at the medical records of 290 women who had breast resection surgery and whose disease did not spread to their lymph nodes. The majority of patients underwent modified radical mastectomies, or removal of most of the breast. Some patients underwent lumpectomies in which only the tumor was removed.
Women with a total count of 20 or more axillary lymph nodes were 4.33 times more likely to die from the spread of their cancer than women with fewer than 20 lymph nodes in the first 5 years after surgery. Over the longer term, the size of the tumor was also found to correlate with the risk of death from the spread of cancer.
``Lymph node number was the only independently predictive factor in the 5-year analysis, and tumor size was the only other factor that retained long-term significance,'' the authors write.
Camp said the finding may stimulate research in the area of lymphatic drainage to help researchers determine how to stop tumors from spreading to lymph nodes.
Breast cancer is the most common cancer among women and the second leading cause of cancer death. According to the American Cancer Society, in 1999, an estimated 175,000 women in the US were diagnosed with breast cancer and there were 43,300 deaths from the disease. SOURCE: Cancer 2000;88:108-113