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Health Research

January 31, 2012

Contact: Amy Whited, Kaiser Permanente Colorado 303-344-7518

New Research Finds Substantial Variability in Rate of Additional Surgery after Partial Mastectomy

Kaiser Permanente Colorado’s Institute for Health Research collaborates on study examining breast cancer re-excision rates using electronic medical records

Kaiser Permanente Colorado contributed to new research that reveals substantial differences — by both surgeon and institution — in the rates of follow-up surgeries for women who underwent a partial mastectomy for treatment of breast cancer.

Journal  of the American Medical Association

Those differences, which cannot be explained by a patient’s medical or treatment history, could affect both cancer recurrence and overall survival rates, according to the study, which appears in the Feb. 1 edition of the Journal of the American Medical Association.

The study included more than 2,200 women with invasive breast cancer undergoing partial mastectomy from four institutions — Kaiser Permanente Colorado, University of Vermont, Group Health and Marshfield Clinic. Data were obtained from electronic medical records and chart abstractions of surgical, pathology, radiology and outpatient records.


“A partial mastectomy is one of the most commonly performed cancer operations in the United States,” said Laurence McCahill, study lead author, a surgeon with Michigan State University’s Department of Surgery. “Currently, there are no readily identifiable quality measures that allow for meaningful comparisons of breast cancer surgical outcomes among surgeons and hospitals.”

Kaiser Permanente Colorado Institute for Health Research

About three-fourths of women battling breast cancer have a partial mastectomy, and nearly one in four of them at some point have another surgery (re-excision) to remove additional tissue. A partial mastectomy is intended to remove cancerous cells while maintaining maximum cosmetic appearance of the breast, but failure to remove all the cells during the initial operation can trigger the need for additional surgery.

The additional operations can produce considerable psychological, physical and economic stress for patients and delay use of recommended supplemental therapies, according to the study, which measured variation in re-excision rates across hospitals and surgeons from 2003 to 2008.