Hypothesis: Sentinel node (SN) biopsy for breast cancer enhances staging sensitivity, often demonstrating only micrometastases (<2 mm) or isolated, keratin-positive cells. When SN metastasis is present, the value of additional axillary dissection is unclear and not all patients benefit from axillary lymph node dissection (ALND).
Design: Prospective cohort study, median 32-month follow-up.
Setting: Multidisciplinary breast cancer centers.
Patients: Forty-six women having SN metastases diagnosed between May 1, 1996, and September 1, 2001, who refused ALND or were recommended to omit ALND owing to serious comorbid conditions.
Interventions: Isosulfan blue dye-directed SN biopsy. Axillary lymph node dissection was not performed. Standard breast irradiation was given. Adjuvant systemic therapy was provided as determined by an oncologist. Interval clinical evaluation was performed.
Main outcome measure: Axillary and systemic failure rates.
Results: Mean patient age was 61.6 years (age range, 36-92 years). Mean tumor size was 1.65 cm (range, 0.4-5.5 cm). Thirty-five (76%) of 46 tumors were ductal carcinomas and 39 (87%) of 45 were estrogen receptor-positive. A mean of 2.6 SNs were identified (median, 2; range, 1-7). Thirty-nine patients (85%) had a single positive SN; the remaining 7 patients (15%) had 2 positive SNs. Seven patients (15%) had macrometastases (>2 mm); 16 (35%) had micrometastases (<2 mm); and 23 (50%) had cellular metastases. Only 16 positive SNs (35%) were seen on hematoxylin-eosin staining, while 30 SNs (65%) had positive immunohistochemical staining. There have been no axillary recurrences. One patient (2%) developed distant metastases during follow-up (range, 4-61 months).
Conclusions: Patients with SN metastases who did not have ALND had a low incidence of regional failure. To confirm this observation, we suggest that patients with SN metastases are ideal candidates for trials evaluating the necessity of ALND.