Study in the Journal of the National Cancer Institute describes newly established PEPI score for use post antiestrogen therapy.
A group of investigators have developed a measurement to establish whether women diagnosed with early-stage breast cancer need to follow surgery with an aggressive regimen of chemotherapy.
Called the preoperative endocrine prognostic index (PEPI) score, it was derived from characteristics of tumors from 228 women with stage 2 and 3 breast cancer underwent four months of antiestrogen therapy with tamoxifen and letrozole before having breast surgery.
The PEPI score takes into account four factors to estimate risk of relapse and survival rates after antiestrogen therapy and before surgery: the size of the breast tumor, whether cancer is present in nearby lymph nodes, how fast tumor cells are multiplying, and whether tumors lose their estrogen receptors.
PEPI scores are derived by assigning a certain number of points to each of these four factors. Preliminary data shows that women with low PEPI scores survived longer on average than those with high PEPI scores.
Patients with a score of zero had almost no risk of cancer recurrence during the five-year follow-up. They had tumors that shrank to stage 0 or 1 or 2A after antiestrogen therapy, and no cancer was present in lymph nodes. Their tumors also had low levels of a marker of cell growth and remained estrogen-receptor positive after antiestrogen therapy.
Women with PEPI scores of four or more are at very high risk of having their cancer return, according to the researchers. They tended to have larger tumors after antiestrogen therapy and were also likely to have cancer in lymph nodes, high rates of tumor cell growth, and tumors that lost their estrogen receptors. These women had about a 50% chance of relapse.
An intermediate group with PEPI scores of 1 to 3 had either large tumors but few of the other dangerous markers or small tumors with more of the dangerous markers. Further study will be needed to determine the relapse risk for this group as well as to validate the PEPI model for predicting breast cancer death.
Researchers on this study are affiliated with Washington University, Institute of Cancer Research in the U.K., Novartis Pharma, Edinburgh Breast Research Unit, Royal Marsden Hospital in London, and Red Cross Women’s Hospital in Munich. Findings were published in the September 23 online issue of the Journal of the National Cancer Institute.