The role of mastectomy for newly diagnosed stage IV – metastatic breast cancer is not well defined. Research has produced conflicting results.
According to publication in the Journal of Clinical Oncology, the surgical removal of the original tumor in the breast significantly improves survival at five years among women with metastatic breast cancer, particularly those with cancer spread to the bone.
Metastatic breast cancer refers to cancer that has spread from the breast to distant sites in the body. Standard treatment for metastatic breast cancer consists of systemic chemotherapy, hormone therapy and or precision cancer medicines. Since the cancer has already spread from the breast in patients with metastatic breast cancer, surgical removal of the original tumor has not been considered standard therapy unless the tumor in the breast is causing discomfort or physiologic problems.
Researchers from Switzerland conducted a study to evaluate whether removing the original cancer in the breast in women initially diagnosed with metastatic breast cancer was beneficial. This study included 300 women in the Geneva Cancer Registry between 1977 and 1996; their initial diagnosis was metastatic breast cancer. The researchers compared survival between the patients who had their original cancer surgically removed to those who did not have surgery.
- Women whose original cancer in the breast was completely surgically removed with no evidence of cancer cells in the surrounding area (negative surgical margins) had a 50% reduced risk of dying from breast cancer than women whose original cancer was not surgically removed.
- At five years 27% of women who had their original cancer in the breast completely removed with negative surgical margins had not died from breast cancer.
- At five years 16% of women who underwent surgery to remove their original tumor, but had evidence of cancer cells surrounding the surgical specimen (positive surgical margins) had not died from breast cancer.
- At five years 12% of women who did not undergo surgery to remove their original cancer had not died from breast cancer.
- Women with cancer spread to the bone derived the greatest survival benefit from the surgical removal of their original cancer in their breast.
- Women who had their axillary (under the arm) lymph nodes removed during surgery derived greater survival benefit than those whose axillary lymph nodes were not removed.
Researchers from the Netherlands have also reported that women who have distant metastatic disease upon diagnosis of breast cancer still benefit from removal of the primary tumor. In fact, these patients appear to survive significantly longer than those who do not undergo surgery.2
They performed a retrospective analysis of 728 women who had distant metastatic disease upon diagnosis of breast cancer, 40% of whom had undergone surgical removal of the primary tumor. The results of the analysis showed that patients who underwent surgery survived significantly longer than those who did not—31 months versus 14. Furthermore, the five-year survival rate among patients who underwent surgery was 24% compared with 13% for patients who did not have surgery.
Other research has suggested that mastectomy is unnecessary . Researchers from India conducted a study that included 350 patients with metastatic breast cancer. All of the women had objective tumor response after 6 cycles of anthracycline based chemotherapy and were stratified by metastatic site, number of metastases, and hormone receptor status. The patients were randomly assigned to one of two treatment arms: Loco-regional treatment (LRT), which included mastectomy, complete axillary dissection, plus radiation therapy; or no loco-regional treatment (No-LRT). For disease progression, women received appropriate systemic treatment.
After a median follow-up of 17 months, median overall survival was 20 months for the non-surgical group and 19 months for the surgical group. Two-year overall survival was 43 percent in the non-surgical group and 41 percent in the surgical group. After adjusting for age, ER status, HER2 receptor status, site of metastases and number of metastatic lesions, there was no significant difference in overall survival between the two groups.
Interestingly, loco-regional treatment was associated with better local progression-free survival, but distant progression-free survival was worse in this group—leading the researchers to hypothesize that removal of the primary tumor might be enabling the disease to spread. In fact, the cited a decades-old animal study in which removal of a primary tumor appeared to release a growth factor that fostered the growth of distant tumors.
The researchers concluded that loco-regional treatment did not provide a survival benefit in women diagnosed with metastatic breast cancer who have responded to first-line chemotherapy. Further study is necessary to determine the optimal role of surgery and patients need to discuss these findings carefully with their treatment team.
References:
- Rapiti E, Verkooijen H, Vlastos G, et al. Complete Excision of Primary Breast Tumor Improves Survival of Patients With Metastatic Breast Cancer at Diagnosis. Journal of Clinical Oncology. Published one-line ahead of print May 15, 2006. DOI: 10.1200/JCO.2005.04.2226.
- Ruiterkamp J, Ernst MF, van de Poll-Franse LV, et al. Surgical resection of the primary tumour is associated with improved survival in patients with distant metastatic breast cancer at diagnosis. European Journal of Cancer Supplements, Vol. 7, No. 3, September 2009. Abstract O-5005.
- Badwe R, Parmar V, Hawaldar R, et al: Surgical removal of primary tumor and axillary lymph nodes in women metastatic breast cancer at first presentation: A randomized controlled trial. 2013 San Antonio Breast Cancer Symposium. Abstract S2-02. Presented December 11, 2013.
