BALTIMORE--A review of randomized trials shows that local recurrence rates for breast-conserving therapy are comparable to those for mastectomy for early-stage patients, Irene Gage, MD, said at a conference sponsored by Johns Hopkins Medical Institutions.
Ipsilateral breast recurrence is seen in about 6% of breast-conservation patients at 5 years and in about 9% at 10 years. Most of these occur in the same quadrant of the breast as the primary tumor site. These true recurrences and marginal misses are observed in the early years after treatment, while recurrences elsewhere in the same breast are more frequent between 5 and 10 years, said Dr. Gage, a radiation oncologist at the Johns Hopkins Oncology Center.
The main risk of recurrence after breast-conserving therapy, she emphasized, is distant failure.
"The risk of an ipsilateral breast recurrence remains fairly constant in the first decade following treatment, and thus patients require continuous monitoring and mammography for years after their initial treatment," she said.
Ipsilateral breast recurrence is accompanied by distant metastases in a minority of cases, and most recurrences are operable. Salvage mastectomies produce 5-year survival rates ranging from 55% to 85%, according to studies cited by Dr. Gage.
The increased risk of ipsilateral breast recurrence may be associated with treatment, pathology, and patient selection issues. For example, an extensive intra-ductal component is a pathologic feature associated with an increased risk of breast recurrence in some series. Other path-ologic factors like lymphatic vessel invasion may be important, but the literature is retrospective, controversial, and inconclusive, she said.
Treatment decisions such as degree of surgery may influence the recurrence rate, Dr. Gage said. Quadrantectomy or wide excision of the primary tumor appears to result in fewer recurrences than lumpectomy or gross excision.