Long-Term Survival and Cure in Distant Metastatic Breast Cancer

Previous data showed that distant metastatic breast cancer (MBC) might be curable in up to 3% of the cases in selected patients, mostly young, with good performance status and with low-volume metastatic disease, mainly by an aggressive multidisciplinary approach including aggressive combination chemotherapy regimens. These long-lasting responses question the belief that MBC is wholly incurable. This study evaluates the rate of long-term survivors and potentially cured patients in an unselected cohort of MBC patients.

We analyzed the data from 342 patients in whom distant MBC was diagnosed from 1990 to 2011. For this study, we defined a metastatic disease survival (MDS) of 9 years as inclusion criterion for long-term survivorship.

Eighteen patients (5.3%) were long-term survivors (MDS: 126 months; range, 108-300 months). The rate of long-term survivors was equally distributed over time (1990-1999: 4.3% vs. 2000-2011: 5.9%, p = 0.63). Compared to patients who had a lower MDS, long-term survivors had significantly more often primary MBC (p = 0.005) and hormone receptor-positive carcinomas (p = 0.015). Age at MBC diagnosis, presence of visceral metastases, and limited number of metastatic sites at the time of MBC diagnosis appeared to have no significant impact on long-term survival. Long-term survival was not associated with the use of chemotherapy (50.0% vs. 65.7% in the control group, p = 0.21). Eight patients (2.3%) developed a complete remission and presented with no evidence of disease at the time of last follow-up (MDS: 234.5 months).

Since long-term survivors in MBC comprise a relatively heterogeneous group, the factors that lead to the quite rare and felicitous case of long-term survival or even cure can hardly be evaluated systematically. Some patients may be considered cured of their disease. This fraction may be small, but the chance of survival, and even of cure, truly exists. Perhaps we must accept that the factors contributing to long-term survival remain an enigma. It appears, however, that aggressive chemotherapy is not the only key factor to long-term remission.