SAN FRANCISCO – Regional recurrence and recurrence-free survival rates were statistically similar in subgroups of 730 patients who had sentinel lymph node–positive, invasive breast cancer and underwent total mastectomy.
The outcomes were comparable regardless of whether or not patients had a subsequent completion axillary lymph node dissection and radiation therapy. A marginally higher 10-year regional recurrence rate of 4.9% in patients who did not have completion lymphadenectomy was not significantly different from rates seen in patients who had completion lymphadenectomy but not radiation therapy (1.4% of whom had a regional recurrence) or in patients who had completion lymphadenectomy plus radiation therapy (3.1% had a regional recurrence), in the retrospective institutional study.
Recurrence-free survival rates also did not differ between groups, reported Dr. Elizabeth FitzSullivan and her associates.
Dr. Elizabeth FitzSullivan
Using the M.D. Anderson Cancer Center nomogram to predict whether lymph nodes other than the sentinel node will have cancer, the investigators predicted a significantly lower probability of additional lymph node positivity in the 98 patients who did not undergo completion lymphadenectomy (a median 10% probability), compared with the 632 patients who had a completion lymphadenectomy (23% probability), reported Dr. FitzSullivan of the University of Texas M.D. Anderson Cancer Center, Houston.
"In select patients with early-stage breast cancer treated with mastectomy with a positive sentinel lymph node biopsy, completion lymphadenectomy may be avoided without adversely affecting recurrence or recurrence-free survival," the investigators concluded in a poster presentation at a breast cancer symposium sponsored by the American Society of Clinical Oncology. The study won a Merit Award at the meeting.
The retrospective analysis of data from patients treated at the M.D. Anderson Cancer Center during 1994-2010 defined completion lymphadenectomy as removal of 10 or more lymph nodes. Median follow-up was 66 months.
In general, patients with early-stage breast cancer who are treated with conserving therapy and who have minimal axillary disease on sentinel lymph node biopsy often don’t undergo completion lymphadenectomy. The increasing rate of total mastectomies heightens the need to identify patients who undergo total mastectomy who may not benefit from completion lymphadenectomy and axillary radiation therapy, the researchers noted.
There were several baseline characteristics that differed significantly between patients who did or did not undergo completion lymphadenectomy in the study. Compared with patients who did have completion lymphadenectomy, those who did not undergo the additional axillary surgery were older (57 years vs. 53 years, respectively); had smaller tumors (a median of 2 cm vs. 2.3 cm); and were less likely to have stage T3 disease (8% vs. 17%), lymphovascular invasion (25% vs. 41%), or extranodal extension of disease (4% vs. 24%). The median size of sentinel node metastasis was smaller in patients who did not have completion lymphadenectomy (1.1 mm) compared with those who did (4 mm).
The symposium was cosponsored by the American Society of Breast Disease, the American Society of Breast Surgeons, the National Consortium of Breast Centers, the Society of Surgical Oncology, and the American Society for Radiation Oncology.
Dr. FitzSullivan reported having no financial disclosures.
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