BIOMARKER INCLUSION IN NEW BREAST CANCER STAGING?

NEW YORK (Reuters Health) Dec 24 - Inclusion of estrogen receptor, progesterone receptor, and human epidermal growth factor 2 (HER2) status could improve the prognostic accuracy of breast cancer staging, according to a new study.

"I believe it is time that we consider biomarkers in our staging system which has been purely anatomic in the past," Dr. Armando E. Giuliano from Cedars-Sinai Medical Center in West Hollywood, California, told Reuters Health by email. "This would improve communication and prognostication."

The current TNM staging system, based as it is strictly on anatomic factors, ignores the prognostic impact of tumor biology, Dr. Giuliano and colleagues noted in JAMA Surgery, online December 4.

The researchers investigated whether the addition of the triple-negative phenotype (TNP; negative expression of estrogen receptor, progesterone receptor, and HER2) to the TNM staging would influence the accuracy of TNM prognosis.

Their study included 1,842 women with breast cancer, 280 (15.2%) of whom were diagnosed with TNP breast cancer. During a median 4.3 years of follow-up, the survival curves for patients with TNP were similar to those for patients with non-TNP at the next higher stage.

In other words, five-year overall survival for stage I TNP (92.3%) was similar to stage II non-TNP (93.4%); for stage II TNP (83.9%) was similar to stage III non-TNP (78.5%); and for stage III TNP (58.4%) approached stage IV non-TNP (34.6%, p=0.76). Five-year overall survival for stage IV TNP was only 14.3%.

Use of the TNM staging system supplemented with biomarker information (B-TNM) significantly decompressed the number of patients with early-stage breast cancer, shifting 15% of all patients to later stages, and as a result, improved the predictive accuracy.

Multivariable models revealed that the B-TNM staging system significantly improved the prediction of five-year overall survival compared with the TNM staging system.

"TNM staging is in jeopardy of becoming obsolete in the 21st century, where an experienced clinician is more likely to relate to a colleague that a patient has a poorly differentiated triple-negative or HER2-positive breast cancer than he or she is to indicate that the same patient has stage II disease," the researchers note.

"Stage reclassification that incorporates TNP status can be a first step in recognizing the importance of nonanatomic factors in the staging of breast cancer and could help clinicians provide better cancer care," they conclude. "This study provides a preliminary proof that the breast cancer staging system could be improved by the inclusion of biomarkers that complement TNM and are available worldwide."

SOURCE: http://bit.ly/1ifMiDH

JAMA Surg 2013.