For the most part, histological type, grade, tumor size, lymph node involvement and standard breast marker panels all play a role in influencing patients’ prognoses and the probability of response to current therapies. The need for existing histological classifications, as well as protein and molecular markers to fully capture the wide variety of clinical courses taken by patients, is a much needed approach.
In addition to standard ER, PR, HER2, Ki-67 and p53 testing, several recent studies have demonstrated that the classification of breast cancer into distinct subtypes can provide clinicians with useful information needed to tailor therapy based on the individual characteristics of their tumor.
ER and HER2 categories are extremely useful because targeted therapies are available and are effective in this specific subset of patients. For example, it has been noted that Luminal-like cancers tend to have the most favorable long-term survival compared with others; whereas Basal-like and HER2 tumors are seen to be more sensitive to chemotherapy1. With these differences, we are finding that there is a need for improved assessment of women with Stage I/hormone-receptor positive/lymph node negative invasive cancer.
References
- Rouzier R, Perou CM, Symmans WF et al. Breast Cancer molecular subtypes respond differently to preoperative chemotherapy. Clinical Cancer Research 2005; 11:5678-5685