Micromets 'No Biggie' in Early-Stage Breast Cancer
Mittendorf EA, Ballman KV, McCall LM, et al
J Clin Oncol. 2015;33:1119-1127
The significance of small-volume axillary disease in breast cancer has been debated for many years. The 2002 edition of the American Joint Committee on Cancer (AJCC) staging established the designation of macrometastases, micrometastases, and isolated tumor cells. In the most recent edition, released in 2006, the designation of T1N1miM0 (axillary micrometastases only) was classified as stage IB (previously it would have been stage IIA).
Mittendorf and colleagues analyzed data from two cohorts of patients with breast cancer, one from MD Anderson Cancer Center (MDACC) treated between 1993 and 2007 and the second from the American College of Surgeons Oncology Group (ACOSOG) Z0010 trial. The latter was a prospective phase 2 trial conducted between 1999 and 2003 to determine the incidence and prognosis of occult metastases to sentinel lymph nodes.
Median follow-up was 6.5 years for the MDACC study and 9 years for the ACOSOG study. In both cohorts, there were no significant differences between patients with stage IA and stage IB disease in 5- or 10-year recurrence-free survival, disease-specific survival, or overall survival. Patients with stage IB were far more likely to receive adjuvant chemotherapy—70% vs 27% in the MDACC cohort.
Patients with micrometastases appear to have outcomes similar to those who are node negative. Estrogen receptor status and grade were found to be related to outcomes. The authors recommend dropping the IB designation and incorporating biologic factors in the next iteration of the AJCC Staging Manual
The study, with an accompanying editorial, provides a very interesting and timely analysis, indicating that the presence of axillary micrometastases and low-volume disease (as indicated by isolated tumor cells) has little or no impact on overall outcomes and should not guide decisions regarding the administration of systemic therapies.
Abstract
Evaluation of the Stage IB Designation of the American Joint Committee on Cancer Staging System in Breast Cancer
Mittendorf EA, Ballman KV, McCall LM, et al
J Clin Oncol. 2015;33:1119-1127
Study Summary
The significance of small-volume axillary disease in breast cancer has been debated for many years. The 2002 edition of the American Joint Committee on Cancer (AJCC) staging established the designation of macrometastases, micrometastases, and isolated tumor cells. In the most recent edition, released in 2006, the designation of T1N1miM0 (axillary micrometastases only) was classified as stage IB (previously it would have been stage IIA).
Mittendorf and colleagues analyzed data from two cohorts of patients with breast cancer, one from MD Anderson Cancer Center (MDACC) treated between 1993 and 2007 and the second from the American College of Surgeons Oncology Group (ACOSOG) Z0010 trial. The latter was a prospective phase 2 trial conducted between 1999 and 2003 to determine the incidence and prognosis of occult metastases to sentinel lymph nodes.
Median follow-up was 6.5 years for the MDACC study and 9 years for the ACOSOG study. In both cohorts, there were no significant differences between patients with stage IA and stage IB disease in 5- or 10-year recurrence-free survival, disease-specific survival, or overall survival. Patients with stage IB were far more likely to receive adjuvant chemotherapy—70% vs 27% in the MDACC cohort.
Patients with micrometastases appear to have outcomes similar to those who are node negative. Estrogen receptor status and grade were found to be related to outcomes. The authors recommend dropping the IB designation and incorporating biologic factors in the next iteration of the AJCC Staging Manual
Viewpoint
The study, with an accompanying editorial, provides a very interesting and timely analysis, indicating that the presence of axillary micrometastases and low-volume disease (as indicated by isolated tumor cells) has little or no impact on overall outcomes and should not guide decisions regarding the administration of systemic therapies.
Abstract
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