Can Immunotherapy Be Effective in Cases of Metastasis?
Some medical terms are equally threatening to medical professionals and laymen alike. “Metastasis” is one such word: even regular patients unfamiliar with biology or medicine know that metastatic cancer is a life-threatening development.
Although the prognosis in such a scenario is rather grim, metastasis is still not a death sentence. The next generation of anti-cancer treatments can offer patients an extended life expectancy and improved quality of life.
Why Is Metastasis Bad News?
Often known as “stage 4 cancer,” metastasis occurs when the primary tumor has spread beyond its original organ, often into a distant body part. When this happens, cells in the new “secondary” tumor will be the same as those of the original one – for example, a metastasized breast cancer may involve a new tumor in the liver, but it will still be made up of mutated breast tissue.
The ability to metastasize is exclusive to cancer cells, and it never happens to benign tumors. Usually, metastasis happens after cancer cells travel through the lymphatic system or the blood vessels. This is why the most common sites for metastasis are the lungs, liver, bones, and brain. However, cancer cells can also travel through the peritoneal wall or the subarachnoid spaces within cells, which may affect any part of the body.
Either way, the spread is “bad news.” Once in their new location, cancer cells will begin overtaking the original organ, impeding its function and causing it to shut down. This is often what eventually causes a patient’s death: several vital organs can be compromised simultaneously, and it is often impossible to be sure that all secondary foci have been located.
How Does Immunotherapy Approach the Treatment of Metastatic Cancer?
There is no single “best” treatment for metastatic cancer. Instead, the chances of success will depend on many factors: the degree in which the tumor has invaded nearby tissues, its size, and the number of organs that have been affected.
But in general, two types of treatment will offer better chances for patients with metastasis: those that can provide body-wide effects (and therefore, “hunt” tumor cells across the body), and those that act in a targeted, individualized way to the characteristics of each patient’s tumor.
Individualized immunotherapy protocols are consistent with both strategies. The fact is that the key principle of immunotherapy is to use the patient’s immune system to recognize cancer cells as “foreign,” just as it does with viruses and other foreign agents entering the body. In doing so, it can act on them without harming neighboring tissues. Moreover, many immunotherapies are developed with a specific tumor mutation in mind, and sometimes even using samples of the original tumor.
In a situation with critically little room for optimism, these highly precise approaches generally extend life expectancy and improve quality of life. However, they work most effectively when patients are in the stage of “minimal residual disease,” that is, when the tumor has shrunk to the smallest possible size. This is a good outcome that can be achieved with which is still achievable with conventional anti-cancer therapies, such as chemotherapy or radiotherapy.