SAN ANTONIO--Final excisional margin status proved to be the strongest
predictor of local recurrence in a study of more than 300 breast
cancer patients treated with breast-conserving surgery and radiation,
Melanie C. Smitt, MD, said at the opening general session of the
San Antonio Breast Cancer Symposium.
Five- and 10-year freedom from local recurrence was 98% among
patients who had negative final margins, compared with 90% and
82%, respectively, for patients with non-negative excisional margins.
The combination of re-excision and negative final margin was associated
with 100% local control versus 78% for patients who did not achieve
negative final margins after re-excision.
Use of adjuvant chemotherapy was the only other significant predictor
of local control, said Dr. Smitt, assistant professor of radiation
oncology, Stanford University Medical Center.
The study involved 303 women with stage I or II invasive breast
cancer. All patients were treated with lumpectomy and radiation.
Adjuvant chemotherapy or tamoxifen (Nolvadex) was limited to patients
with positive lymph nodes and other high-risk features.
A surgical margin was defined as negative if a tumor-free zone
of greater than 2 mm was achieved. A close margin was less than
2 mm. Positive margins were defined as focal or diffuse. Re-excision
was performed as deemed appropriate.
Initially, only 17% of patients had a tumor-free margin. More
than 40% had indeterminate margins after primary excision (see
table). Following re-excision, final margins were negative in
half the patients and indeterminate in 35%.