"Our inability to make that distinction, to predict who is at risk for distant spread and who is cured by surgery, has resulted in treatment that is too much for most and too little for some," adds co-author Samuel Hellman, M.D., the A.N. Pritzker Distinguished Service Professor of radiation and cellular oncology.
The study used tumor tissue from 163 patients, median age 57, treated at the University of Chicago Hospitals between 1927 and 1987 with mastectomy alone. These patients received no additional radiation, hormone or chemotherapy. Most had fairly small tumors, three centimeters or less, and no lymph node involvement. They were followed for an average of 14 years, some as long as 36 years.
The researchers found that low MVC -- few new capillaries -- was associated with excellent prognosis. High MVC, they note, "appears necessary but not sufficient for metastasis to occur."
Unfortunately, the growth of new blood vessels tends to occur quite early for most cancers; even small tumors found via mammogram frequently have a high MVC. However, patients with high MVC combined with high protective levels of nm23 also do quite well, 90 percent surviving 14 years.
The study also provides insights into the progression of breast cancers, suggesting that angiogenesis and metastasis are two separate and usually sequential events.
Decreased levels -- or mutant, nonfunctional versions -- of nm23 seem to appear somewhat later than angiogenesis. Loss of nm23 appears to be a crucial second event that must occur before the cancer can spread to distant sites.
While these markers are useful, they do not tell the whole story, insist the
authors, since even for those with both high angiogenesis and non-functioning
nm23 about 70 percent survive. This indicates that there are other as yet
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Contact: John Easton
jeaston@mcis.bsd.uchicago.edu
773 702 6241
University of Chicago Medical Center
1-Jul-1998