Breast cancer is the most common cancer in American women, excluding skin cancers. There is a 1 in 8 chance that a woman will develop breast cancer during her lifetime. While incidence rates are rising, death rates have dropped dramatically over the last 30 years.1
Breast cancer is generally treated either surgically or systemically, depending on the diagnosis. There are various kinds of breast cancer which respond differently to specific treatments. Over time, new treatments have been developed to target the underlying cause of specific cancers.
Stage IV breast cancer
Stage IV, also known as metastatic breast cancer, occurs when the disease has spread to one or more additional areas of the body, such as bones, liver, lungs, or brain. Spread often occurs through the lymph system or bloodstream. The typical treatment has been with systemic therapy.4
Systemic therapy treatment option
Drug treatment has been the primary approach for most women with Stage IV breast cancer. Hormone therapy, chemotherapy, and targeted drug treatment are generally prescribed alone or in combination to attack the cancer. Types of drugs used for stage IV breast cancer depend on the hormone receptor status and the HER2 status of the cancer.
Local treatment options
Surgery, like radiation, is considered a local treatment for stage IV breast cancer. Traditionally it has not been used for Stage IV Breast Cancer or has been performed after systemic therapies were used to shrink a tumor, allowing the tumor to be more easily surgically removed.2 But removing tumors is not considered a cure.
New studies suggest surgery is an option that may result in longer survival when considered alongside targeted therapy, and other standards of care. Study authors recognized the importance of analyzing the HER2 subsets and distinct therapies when making clinical recommendations.2,3
For women who have anti-human epidermal growth factor receptor HER2+ disease, systemic therapy has produced positive outcomes. HER2+ breast cancer is characterized by tumors that overproduce a specific molecule known as human epidermal growth factor receptor-2, or HER2. Herceptin is a drug used to treat HER2+ breast cancer. It has been used alone and in combination with other chemotherapy drugs.
In a recently published study out of California, investigators sought to look at the impact of primary tumor resection on survival in HER2+ stage IV breast cancer patients since the recognition of HER2 targeted therapies.2 They examined outcomes for 3,200 cases from the National Cancer Database, from the start of HER2 data collection in 2010 to 2012. Although prior study results have been variable, the most recent findings determined that women with metastatic HER2-positive breast cancer lived longer if they had surgery for the primary tumor.
The researchers identified and controlled for covariates, variables that were measured but not considered in the original outcomes. These covariates included age, ethnicity, and type of health insurance. This information, when analyzed in combination with outcomes, improved accuracy of the final analysis.
Surgery of the primary site in metastatic HER2+ breast cancer is associated with improved overall survival. With the surgery median overall survival (OS) was 25 months, as compared with 18 months for those that did not have surgery. To be sure, study results have been inconsistent. A large study from India showed no improved rate of survival with surgery, whereas one in Turkey found that surgery lowered the risk of premature death by a third.
When considering treatment strategies, doctors should discuss surgical options with their patients based on each patient’s specific evidence-based clinical makeup.2 Future studies of surgery for stage IV breast cancer will likely address issues related to effects timing has on different therapies.
Variables noted of those who had primary site HER2+ breast cancer surgery included being younger, at a lower income level, more likely to have private insurance or Medicare coverage, and treatment at a community cancer center. Other factors besides surgery associated with a longer survival included older age, Medicare coverage, and drug treatments with systemic agents. 3
How common is breast cancer? Available at: https://www.cancer.org/cancer/breast-cancer/about/how-common-is-breast-cancer.html. Accessed 5.1.19
Mudgway,R. Chavez de Paz Villanueva, C. The impact of primary tumor surgery on survival in HER2 positive stage IV breast cancer patients in the current era of targeted therapy Available at: https://www.abstractsonline.com/pp8/#!/6812/presentation/6349. Accessed 5.1.19
Bankhead, C. Role for Primary Surgery in Stage IV Breast Ca? Available at: https://www.medpagetoday.com/meetingcoverage/aacr/79010. Accessed 5.1.19
Treatment of Stage IV (Metastatic) Breast Cancer. Available at: https://www.cancer.org/cancer/breast-cancer/treatment/treatment-of-breast-cancer-by-stage/treatment-of-stage-iv-advanced-breast-cancer.html. Accessed 5.1.19