Tumor size helps predict survival in node-negative breast cancer patients

Research from investigators at The Cancer Institute of New Jersey (CINJ), UMDNJ-School of Public Health (SPH) and UMDNJ-Robert Wood Johnson Medical School, indicates that tumor size stratified by age, race and hormone receptor status helps predict survival in node-negative breast cancer patients. With this information, researchers say the current breast cancer staging system in patients whose cancer has not spread to nearby lymph nodes (node-negative) can be enhanced, and that this may be useful in allowing clinicians to more accurately predict outcomes for these patients. The research was part of an oral presentation recently given at the Society of Surgical Oncology's 65th Annual Cancer Symposium held in Orlando. CINJ is a Center of Excellence of the University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School.

Lymph node staging is the major predictive factor of survival in women with local/regional breast cancer, but with improvements in screening and detection, cancers are identified earlier and diagnosis of node-negative breast cancer has become more common. Better risk prediction in node-negative breast cancer patients is needed to help counsel women concerning prognosis. Investigators at CINJ and UMDNJ-SPH used Surveillance, Epidemiology, and End Results (SEER) data to investigate the use of more detailed tumor information (tumor size in conjunction with age, race and hormone receptor status) to improve prognostication in women newly diagnosed with node-negative breast cancer.

The study, Risk Categorization of Women with Node-Negative Early Stage Breast Cancer by Tumor Size, included 150,659 Caucasian, 15,849 Hispanic and 14,103 African-American women aged 18 and older with node-negative, early-stage breast cancer diagnosed between 1994 and 2008. All were treated for their disease with lumpectomy followed by radiation or mastectomy. Tumor sizes in increments of one millimeter were then evaluated for important changes in survival in women placed into 12 risk groups that varied by age, race and receptor status. Five-year cumulative survival estimates were determined. The data also were adjusted for tumor grade.

Overall the research showed that differences in survival were seen for women with the same tumor size depending on which risk group they were in. Among women who were hormone-receptor positive and younger than 50 years old, a 1.5-centimeter tumor predicted a 98 to 99-percent five-year survival rate (98-percent in African-Americans and Hispanics; 99-percent in Caucasians). In women under 50 years old with negative receptors, the same tumor size predicted a 91- to 93-percent five-year survival rate (93-percent Caucasians, 92-percent Hispanics, 91-percent African-Americans).

In women 50 years of age and older with positive receptors, a 1.5-centimeter tumor predicted a 97 to 98-percent survival rate (98-percent for Caucasians and Hispanics; 97-percent for African-Americans) but a 91- to 93-percent survival rate (93-percent Caucasians and Hispanics; 91-percent African-Americans) in the receptor negative group.

Differences also were seen among patients with larger tumor sizes. For example, a four-centimeter tumor in Caucasian, Hispanic and African-American receptor positive women younger than 50 years old predicted a 97-percent, 96-percent and 94-percent five-year survival respectively, but in the receptor negative group, women with the same tumor size had a predicted five-year survival of 87- to 88-percent (88-percent Hispanics; 87-percent Caucasians and African-Americans). Similar differences were seen in women 50 years of age and older between the receptor negative and positive groups.

Michelle Azu, MD, FACS, breast surgical oncologist at CINJ and assistant professor of surgery at UMDNJ-Robert Wood Johnson Medical School, is the lead researcher on the study. "Because of the continued advancements in the way we diagnose and treat breast cancer, it is imperative for healthcare professionals to have comprehensive information available to them when measuring prognosis," said Dr. Azu, who also is an assistant professor of epidemiology at UMDNJ-SPH. "By further exploring this area and determining why survival for a given tumor size differs by risk groups defined by age, race and receptor status, we will be able to provide better counsel to node-negative patients on their expected outcome. In terms of survival, one size does not fit all."

Source The Cancer Institute of New Jersey