NIH Press Release
National Cancer Institute

Tuesday, June 2, 1998
4:00 PM Eastern Time

NCI Press Office
(301) 496-6641

Modest Risks Found in First
Population-Based Study of Outpatient Mastectomies

Researchers from the National Cancer Institute (NCI) and the Health Care Financing Administration (HCFA) have found a marked increase in outpatient mastectomies in women from 1986 to 1995 and a modest increased risk for some surgery-related complications in a small percent of women. The results were reported in the June 3 issue of the Journal of the National Cancer Institute*.

This is the first large population-based study to explore utilization trends and outcomes following outpatient mastectomy. The study included all women ages 65 and older in the fee-for-service Medicare program between 1986 and 1995. More than 90 percent of Medicare enrollees during these years had fee-for-service coverage.

The number of outpatient mastectomies, where surgery is done without an overnight stay, increased from virtually 0 percent in 1986 (two of 47,295 procedures) to 10.8 percent in 1995 (4,831 of 44,940 procedures). During the same study period, a decisive shift toward decreasing lengths of stay for mastectomies occurred. From 1986 through 1988, 46.9 percent of the total 117,982 mastectomy patients stayed six or more days in the hospital. By 1993 to 1995, only 11 percent of the total 118,336 mastectomy patients stayed six or more days. Among the remaining patients during that period, 18.6 percent stayed overnight or had an outpatient procedure; 29.2 percent stayed two days; 22.5 percent stayed three days; 12.6 percent stayed four days; and 6.3 percent stayed five days.

Researchers compared health outcomes following inpatient and outpatient mastectomy by calculating the risk of being re-hospitalized and describing the reasons for it. Women undergoing outpatient procedures were compared with women who had mastectomies involving hospital stays of one day to six-plus-days. Reasons for re-hospitalization within 30 days of discharge were categorized as either definitely surgery-related, possibly surgery-related, or other conditions. Surgery-related complications included wound infection, seroma/hematoma, and pulmonary embolism/deep vein thrombosis. Possible surgery-related effects included nausea, vomiting, syncope, pneumonia, sepsis, and urinary tract infections.

Assessing outcomes from the time of discharge, when a patient is considered ready to go home, women treated on an outpatient basis had significantly higher rates of re-hospitalization compared to women with a one-day stay. Outpatients undergoing simple mastectomy (total removal of the breast) were 84 percent more likely to be re-hospitalized within seven days of discharge, and 43 percent more likely to be re-hospitalized within 30 days. Outpatients undergoing modified radical mastectomy (total removal of the breast and some lymph nodes under the arm) had a 72 percent greater likelihood of re-hospitalization within seven days of discharge, and a 28 percent greater likelihood within 30 days. (No association was found between treatment setting and any emergency room visits within 30 days after discharge.)

However, the researchers observed that any difference in re-hospitalizations between women with an outpatient mastectomy and a one-day stay reflected a relatively small number of cases. The total proportion of women undergoing simple and modified radical mastectomy who were re-hospitalized was just 1.5 percent at seven days of discharge and 4.2 percent at 30 days.

Outpatients and patients with a one-day stay had nearly equal rates of re-hospitalization for complications that were definitely related to their surgery. The women most likely to be re-hospitalized for definite surgery-related reasons were those whose initial hospitalization for the mastectomy had been for three or more days. These women may have had a more advanced stage of cancer or poorer health status that placed them at greater risk of re-hospitalization, according to the researchers.

"These results show that for the women in this study who underwent outpatient mastectomy, the risks of surgery-related complications were modest in terms of both the degree of relative risk and the types of health complications reported. However, the slightly higher rates of hospital readmission suggest that ongoing monitoring of the use and outcomes of outpatient mastectomy is needed, particularly if there is broader utilization of this procedure," said Joan Warren, Ph.D., of NCI's Applied Research Branch, Division of Cancer Control and Population Science. "Furthermore, it is important to note that this study did not address an important aspect of assessing outpatient mastectomy, namely women's satisfaction with undergoing an outpatient procedure."

Outpatient mastectomies were more likely to be performed in for-profit or non-teaching hospitals in large metropolitan areas. Women treated in for-profit hospitals were 56 percent more likely to have outpatient surgery than women treated in non-profit hospitals. The researchers suggested that hospitals may be responding to Medicare reimbursement incentives established in the early 1980s, which favor outpatient surgery because of the potential for cost savings for Medicare and for increased profits for hospitals.

The reimbursement incentives also may explain some of the significant geographic variation in use of outpatient mastectomies. Two states, Florida and Arizona, accounted for 23 percent of all outpatient mastectomies occurring in the United States. In 22 states, less than 5 percent of mastectomies were performed in an outpatient setting. Using data from the American Hospital Association, the researchers found that states with more for-profit hospitals had higher rates of outpatient mastectomies performed.

Women with no pre-operative coexisting health problems were also more likely to undergo outpatient mastectomy. Pressure to increase the number of women undergoing outpatient mastectomy may result in the selection of women who are not optimal candidates for an outpatient procedure, the researchers emphasized.

Data were obtained from HCFA's Medicare program on all simplified and modified radical mastectomies reported during the study period, and were confirmed for accuracy by linked data from NCI's Surveillance, Epidemiology, and End Results (SEER) Program, a set of geographically defined, population-based central tumor registries in the United States.

This study does not yield information about women under 65. However, more than 45 percent of breast cancer cases and 60 percent of deaths occur in women ages 65 and older. Medicare managed care enrollees, or postoperative complications that may have been treated in physicians' offices were not included.

*The article is entitled "Trends and Outcomes of Outpatient Mastectomy in Elderly Women." The authors are Joan L. Warren, Gerald F. Riley, Arnold L. Potosky, Carrie N. Klabunde, Elizabeth Richter, and Rachel Ballard-Barbash.