The National Cancer Institute (NCI) has it that, in the United States alone, about 266,120 will receive a breast cancer diagnosis in 2018. Moreover, and sadly, about 41,000 of those diagnoses will result in death.
Nevertheless, the NCI’s records indicate that the number of deaths resulting from breast cancer have been on a steady decrease since the early 90s. Additionally, the 5-year survival rate for an individual diagnosed with breast cancer now lies at about 90 percent.
Upon being diagnosed with breast cancer, the individual’s outlook will be determined by several factors; however, the most important one is the extent of the cancer in addition to whether it has spread beyond the tumor’s original site.
The 5-year survival rate for women who have stage-2 breast cancer, for instance, is at approximately 93%. However, if the cancer starts to spread – also known as metastasizing – that rate drops to 22%.
Consequently, scientists are directing more and more of their focus and resources towards understanding the process of metastasis with the hope that gaining more insight on the subject will allow them to have better strategies for prevention.
Understanding Metastasis
Cancer is bad enough when it is just in one spot; however, when it begins migration to other sections of the body is when the disease is at its most dangerous. Thus, finding solutions to stopping metastasis is one of the best ways to enhance the survival rates of women with breast cancer.
Researchers have now discovered that primary tumors, in fact, have a mechanism that allows them to slow down the rate of growth of secondary cancers. This new discovery is presenting us with the possibility of a new potential breast cancer treatment option.
Any treatment we direct at tumor is not going to be of much help if it does not stop the tumor from traversing through the body. Therefore, metastasis has become one of the key areas of focus in cancer research. Recent findings have identified multiple mechanisms used by cells to break away from the primary tumor in addition to the proteins that protect those cells as they travel across your body. These findings are also being investigated as potential sources of treatments.
By examining the mechanism of metastasis, scientists in a recent study have been able to pinpoint a strange new ecosystem that has gone unnoticed all this while. On experiments done on mice, researchers discovered that primary breast tumors can transmit signals to the cells that have broken away and already travelling to other sections of the body. These messages, surprisingly, are actively barring secondary tumor growth.
These new findings, published in the journal Nature Cell Biology, have allowed us to get a better understanding of how metastasis works in breast cancer.
The Study
In a nutshell, findings from the study revealed that primary breast cancers have the ability to stop themselves from spreading.
The researchers who performed this study were jointly led by Dr. Christine Chaffer, from the Garvan Institute of Medical Research in Sydney, Australia, and Dr. Sandra McAllister, from Harvard Medical School.
According to Dr. Christine Chaffer, this research has created that rare possibility – a sign from the cancer itself of the potential possibilities that can help fight its spread. She adds that the goal of their research is to plot how they can mimic how the primary tumor freezes the secondary cancers. This will allow them influence over breast cancer in the future by keeping the secondary tumors in check.
In their research, the scientists discovered that, in mice, the primary breast tumor still has some influence over the cells that have broken away and left the tumor to establish other tumors in other body sections. The primary tumor influences these breakaway cells by sending a message via the immune system, which is an inflammatory response triggered by the tumor.
The inflammatory response is characterized by immune cells spreading through the body and pinpointing locations where the rogue cells have settled in as they prepare to launch new secondary tumors. Upon locating those cells, the immune cells are remarkably able to freeze them, thus stopping tumor growth.
The reason why immune cells are successful at freezing the breakaway cells is that, before the rogue cells are able to establish a new tumor, they are usually in an intermediate state which is very vulnerable to attacks from the immune system.
Thus, by forcing those breakaway cells to remain in their intermediate state, they are not able to grow well hence severely compromising their ability to create a new tumor. Thus, interestingly, by triggering the immune system, the primary tumor inadvertently shuts down its own spread.
Remarkably, indirect evidence suggests that the same process might also be occurring in people. The researchers discovered that, in a group consisting of 215 breast cancer patients who were at a pronounced risk of developing metastasis, the patients who featured a heightened level of the immune response as was found in the mice, also showed better overall survival rates as compared to those who showcased lower levels.
The scientists are now plotting how to properly apply this new discovery in the clinic. According to Dr. Chaffer, when one has a primary tumor, the number of breakaway cells that are going to traverse through the body is unquantifiable. However, not all of them result in tumors. In fact, estimates show that less than 0.02 percent of those breakaway cells eventually go on to form secondary tumors. The implication is that we now have a real possibility of bringing down that number to zero.
The researchers have even discovered some of the signals being used by the immune cells to keep metastasis under control. Nevertheless, the scientists have cast a wide net and are looking at metastasis from multiple angles. They aim to understand the exact thing being produced by the tumor to trigger that particular immune response, in addition to understanding the exact mechanism the immune cells use to attack the secondary sites.
By understanding all the above steps, treatment approaches that inhibit the spread of breast cancer can be developed. If successful, these treatment approaches will then be exploited to stop the spread of other types of tumors as well.
