This new study assessed time trends in survival for 1,361 metastatic breast cancer patients over the past 15 years. Trends in survival were examined using the following time periods: 1991-1994; 1995-1998; 1999-2002; and 2003-2006. Median survival was found to have increased significantly over time: 1.28 years during the period 1991-1994; 1.68 years during 1995-1998; 2.20 years during 1999-2002; and 2.57 years during 2003-2006. Taking into account important prognostic factors such as hormonal receptor status, previous chemotherapy, previous adjuvant hormonal treatment, and number of metastatic sites had little effect on the result. However, the improvement in survival over time can be explained by the introduction of new treatments such as taxanes and Herceptin.

Other factors that could improve survival time for metastatic breast cancer

Chemotherapy and hormonal drugs are the main treatment options once breast cancer has spread and, for the most part, they are the only effective treatments. However, there are two other factors that could be important to length of survival in some women. First, there is evidence that a metastasis can have different receptor status (estrogen receptor, progesterone receptor, HER2) than the original tumor in the breast. Treatment for what amounts to the wrong receptor status is possible if the receptor status of metastases is not taken into account. The idea that it would be best to tailor treatment to the receptor status of metastases appears reasonable since breast cancer cells that have metastasized presumably are the most aggressive and therefore should be targeted.

Second, numerous studies have found that surgically removing the primary tumor and solitary metastases can improve survival. The implication is that women who did not obtain clean margins as a result of breast conserving surgery (lumpectomy) after diagnosis (or who had extensive DCIS or LCIS in addition to invasive breast cancer tumors) might still benefit from mastectomy once the cancer has metastasized. Women who develop a single metastasis may have an opportunity to extend survival by surgically removing the new tumor, if possible. For example, several studies have found that it may be worthwhile to remove a solitary bone metastasis both for purposes of pain relief and to materially extend survival.