TUESDAY, Sept. 13, 2005 (HealthDay News) -- The surgery used to remove breast cancers may, in rare cases, help encourage the formation of a new blood supply for metastatic cancer recurrence later on, a new study suggests.
The finding could help explain a pattern of early relapse in younger breast cancer patients, U.S. researchers add.
Researchers led by Michael Retsky of Childrens Hospital Boston analyzed data from nearly 1,200 breast cancer patients enrolled in three clinical trials. The women had surgery for breast cancer but no other treatment.
The study identified two key post-surgical periods for relapse among these patients -- at 18 months and at five years. Further analysis revealed that 20 percent of premenopausal breast cancer patients whose cancer had spread to the lymph nodes (positive nodes) relapsed within 10 months of their surgery to remove the primary beast cancer tumor.
"Cancer outgrowth after surgery has been observed for over 100 years, and the mechanisms have not been fully identified," study leader Michael Retsky, an investigator in the Vascular Biology Program at Children's Hospital Boston, said in a prepared statement. One theory has been that surgery may help induce angiogenesis -- the formation of new blood vessels that feed the tumor. Angiogenesis is a key component in the growth and spread of new cancer.
Calculations based on the study data predicted that surgery-induced angiogenesis would accelerate cancer by a median of two years and produce 0.11 early deaths per 1,000 screened young women in the third year of breast cancer screening.
"Our analysis suggests that biology may be the underlying cause, rather than something going wrong during surgery. It also suggests that while most young women benefit from early detection of breast cancer, a small percentage will relapse and die early of metastatic disease. The paper suggests remedial steps that might prevent the sudden growth from occurring," Retsky said.
"The results of this study could also be considered when designing treatment protocols for young women with positive nodes, since it may not be coincidence that adjuvant chemotherapy works best for those patients," Retsky said.
Breastcancer.org has more about breast cancer surgery.