Long-Term Non-progression in Metastatic Breast Cancer Beyond 5 Years: Case Series and Review

Metastatic breast cancer (MBC) was traditionally viewed as homogeneously progressive and incurable among all comers, but there is new evidence that MBC harbors a range of tumor molecular/immune subtypes and degrees of aggressiveness. Thus, MBC is not rapidly fatal in all affected patients. A small subset of patients will attain long-term disease control, or undetectable disease, and will enjoy a prolonged survival with little disability from their disease or treatment. Though the term is controversial, some patients with long-term non-detectable disease may effectively be considered “cured”. To best advise treatment options in these patients, it is imperative to identify patients most likely to benefit from aggressive treatment. In this review, we delineate the clinical, pathologic, and disease characteristics associated with long-term non-progression in MBC. We include a single institution case series of long-term non-progressive MBC patients and their characteristics as an example of the frequency of this sub-population of MBC. Future prospective trials are warranted to examine the utility of clinical characteristics as predictors of long-term survival in MBC.