Dr. Sharma said that no conclusions could be drawn about the risk of LRR in patients with three positive nodes because “this was a very rare event,” with only 21 patients meeting the criteria.
The 10-year LRR rate among patients with T2 tumors and lymph node metastases was 9.7%, which was significantly higher than the rate of less than 3% for their counterparts with T1 tumors with and without nodal metastases and those with T2 tumors and no nodal metastases.
“Although the 9.7% rate of locoregional recurrence is significantly higher compared with the other groups of patients, it is important to note that at this level of risk, experts have estimated that approximately 100 women would need to be treated to potentially obtain a survival benefit in one or two patients,” Dr. Sharma said.
She also reported that 25 contralateral breast cancers developed during the study period.
Although the median time to occurrence of contralateral breast cancer was longer than the time to development of LRR (a median of 7.2 years vs. 3.8 years, respectively), there was no significant difference between the rates of a locoregional or a contralateral event between the two groups (5.5% vs. 2.7%, respectively).
This was true for node-negative patients and for patients with one to three positive lymph nodes.
Dr. Sharma acknowledged the potential for bias in the study, including the fact that patients who received neoadjuvant chemotherapy were excluded.
“Those patients likely presented with more advanced disease. That might have altered results if those patients were included.”
Dr. Ranjna Sharma (left) and Dr. Henry M. Kuerer found low locoregional recurrence rates in T1, T2 breast cancer patients treated with surgery, adjuvants.
Source Courtesy Sandra Soule
My Take
Prospective Trial Is Needed
The findings reported at the Society of Surgical Oncology are provocative, and may cause a shift away from a trend to recommend postmastectomy radiation to all women with lymph node–positive breast cancer—even those with one to three involved axillary nodes. Although the report is based on a large number of subjects, it is limited by its retrospective nature and the few local and regional recurrences that did develop.
Even with those limitations, the study finds that certain subsets of patients appear to have a risk of local recurrence (in the absence of postoperative radiation therapy or primary chemotherapy) that is not unlike the risk in patients with T1 and axillary node–negative disease. This suggests that the use of postmastectomy radiation therapy may be better directed toward patients with larger primary tumors, those with more than one involved axillary node, and those younger than 40 years at diagnosis. To confirm these findings, a prospective trial of postmastectomy radiation therapy, or not, will be required.
DR. WILLIAM J. GRADISHAR is a professor of medicine at Northwestern University and director of Breast Medical Oncology at the Robert H. Lurie Comprehensive Cancer Center in Chicago.
