Study: Immunohistochemical staining of sentinel nodes, bone marrow not clinically warranted in early-stage breast cancer

Giuliano AE. JAMA. 2011;306:385-393.

Issue: August 25, 2011

Detecting sentinel lymph node metastasis on immunochemical staining was not associated with survival among women with early-stage breast cancer who received breast-conserving surgery and lymph node dissection, according to data from a prospective, observational study.

Researchers from the American College of Surgeons Oncology Group conducted the Z0010 trial, which enrolled 5,210 women with clinical T1 to T2N0M0 invasive breast cancer from May 1999 to May 2003 across 126 sites. All patients underwent breast-conserving surgery and sentinel node dissection, according to the researchers. As of March 2001, all patients were required to have bone marrow aspiration completed at the time of operation. Lymph node and bone marrow samples were sent to a central laboratory for staining. The primary and secondary endpoints were OS and DFS.

More than 75% of sentinel lymph node biopsies were tumor-negative, according to hematoxylin-eosin staining. Immunohistochemical staining was used to examine 3,326 sentinel lymph node specimens and 3,413 bone marrow specimens; 10.5% of sentinel lymph node specimens and 3% of bone marrow specimens were positive for tumor.

Median follow-up was 6.3 years, at which time 435 patients had died and 376 had recurrent disease. Five-year OS rates were not significantly linked to immunohistochemical evidence of sentinel lymph node metastases, according to the researchers: 95.7% (95% CI, 95-96.5) for immunohistochemistry-negative and 95.1% (95% CI, 92.7-97.5) for immunohistochemistry-positive disease (HR=0.90; 95% CI, 0.59-1.39). Bone marrow metastases were associated with increased mortality (HR=1.94; 95% CI, 1.02-3.67) but not increased recurrence. Five-year OS rates were 95% (95% CI, 94.3-95.8) for those with immunocytochemistry-negative specimens and 90.1% (95% CI, 84.5-96.1) for those with immunocytochemistry-positive specimens (P=.01).

On multivariable analysis, neither tumor evidence in sentinel lymph nodes (HR=0.88; 95% CI, 0.45-1.71) nor tumor evidence in bone marrow (HR=1.83; 95% CI, 0.79-4.26) were statistically significant.

“Data from Z0010 show that occult metastases detected by immunohistochemistry are not associated with survival differences in patients with the earliest stages of breast cancer,” the researchers wrote. “Although longer follow-up might reveal small differences in outcome, these are likely to be of no clinical significance.”

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