CHICAGOMedical contraindications to breast-preserving cancer surgery occur in a minority of patients with early-stage breast cancer when accepted clinical guidelines are appropriately applied, results from a series of more than 400 patients suggest.
Contraindications to breast preservation were found in 97 (22.5%) of 432 patients whose early-stage breast cancer was diagnosed over a five-year period at Northwestern University Medical Center. The most common contraindication was the presence of multifocal or multicentric disease.
However, the incidence and type of contraindications varied by tumor stage, Monica Morrow, MD, said at a general session of the San Antonio Breast Cancer Symposium.
Six prospective, randomized trials have demonstrated the survival equivalence of breast-conserving surgery and mastectomy. Nonetheless, more than half of US women diagnosed with early breast cancer continue to have mastectomies, said Dr. Morrow, director of the Lynn Sage Comprehensive Breast Center at Northwestern.
Several small studies have suggested that contraindications to breast preservation exist in as many as 40% of women with early-stage breast cancer, she said. The results have helped fuel enthusiasm for neoadjuvant chemotherapy as a means of increasing the rate of breast-conserving surgery.
Dr. Morrow and her colleagues evaluated the incidence of contraindications to breast conservation in 432 patients referred for treatment of early-stage breast cancer from June 1988 to June 1993. There were 96 cases of ductal carcinoma in situ (DCIS), 167 cases of stage I breast cancer, and 169 cases of stage II cancer.
Contraindications were identified by use of criteria established by the Joint Committee of the American College of Surgeons, American College of Radiology, and the College of American Pathologists (see table at right). By use of those criteria, 335 of the 432 patients qualified for conservation.
Multifocal or multicentric disease was the most common disqualifying factor, accounting for 39 of 97 contraindications. Diffusely abnormal mammograms and a large tumor-breast ratio accounted for 25 contraindications each.
The incidence of contraindications was 33% for DCIS, 10% for stage I patients, and 29% for stage II patients. Multifocal/multicentric disease accounted for half the contraindications in DCIS patients. A diffusely abnormal mammogram was the most common contraindication in stage I patients, accounting for 40% of the contraindications. A large tumor-breast ratio constituted about 35% of the contraindications in stage II patients, making it the most common disqualifying factor in that group.
Although positive nodes are not a contraindication to breast conservation, when all women with invasive cancer were considered, node status was a factor in the rate of breast conservation, with 82% of node-negative patients receiving conservation versus only 55% of node-positive patients.
Node Status and Tumor Size
This difference disappeared, however, when, to eliminate the influence of tumor size, only patients with stage II cancer were considered. Among these patients, the conservation rate was 52% in node-negative women and 55% in those with positive nodes.
Using node status as a criterion for breast-conserving surgery may reflect "a basic misunderstanding of the rationale for breast conservation, which is to improve cosmesis," she said.
Use of breast conservation did not differ by tumor histology or patient age. "Women older than 70 opted for preservation as often as those younger than 40," she said.
Caucasians were significantly more likely to have breast conservation, but the difference was due almost entirely to an increased frequency of pregnancy, prior radiation, and social contraindications (circumstances that prevent the patient from receiving regular radiation) in non-Caucasians.
The investigators also looked at the potential impact of neoadjuvant therapy on breast preservation rates. They found that only 20 women (less than 6% of the total patient population) needed mastectomy because of a large tumor-breast ratio.
"If, based on the published literature, you assume a complete and partial response rate of 80% for operable breast cancer patients receiving neoadjuvant chemotherapy," she said, "this means that 16 additional patients could have undergone breast preservation, increasing the overall preservation rate from 77.5% to 81%."
Thus, she concludes that "neoadjuvant therapy is extremely unlikely to have a major impact on the breast preservation rate in this country and should be judged on its own merits for decreasing rates of distant relapse, rather than as a method of improving cosmesis."
'Even at This Late Date . . .'
In response to a question from the audience, Dr. Morrow said that "physician bias and misunderstanding of contraindications play a much larger role than one might anticipate at this late date in breast preservation."
In geographic areas that have very low published rates of breast preservation, she said, "you see that things such as poor prognosis disease, dense fibrocystic disease, and tumor location are still being considered contraindications to breast preservation, even though there are no supporting data."
In addition, she said, some surveys suggest that many surgeons still believe that mastectomy is a more effective therapy than breast preservation, "and they convey that impression to their patients."