Chemotherapy and radiation, along with surgery, are the most common treatments for breast cancer, but medical science is working on changing that. Immunotherapy, a form of therapy that uses parts of a person’s immune system to fight cancer, has been used to treat Non-Hodgkin’s Lymphoma successfully, and scientists are now working to use it to treat certain types of breast cancer as well.

A study currently underway combines an immunotherapy drug called Tecentriq with chemotherapy for patients who have advanced triple-negative breast cancer. These cases mean that the cancer is not fed by hormones or genes. The patients in these studies receiving the double treatment went two months more without their cancer worsening than those who received chemo alone. Although those numbers don’t imply much success, the patients in the study lived almost a year longer than those who received chemotherapy alone. Scientists are hopeful that with more study time and more trials, they will continue to adjust the drug to target those particular cells.

There are currently three other immunotherapy medications approved for clinical trials that target particular antibodies in patients with breast cancer. The first two, pertuzumab and trastuzumab, are approved for early-stage breast cancer after surgery. The third option, trastuzumab emtansine, is approved for tumors for particular groups of patients.

So if these medications are doing so well, why aren’t they mainstream yet?

Cost plays a big part in deciding to use the medication. While chemotherapy alone runs a couple thousand, The Washington Post reports that the cost is higher with immunotherapy meds, “which can cost $10,000 a dose or more.” Many people who are going through treatments are doing so with health insurance, but are still being asked to pay parts of their deductibles, not to mention additional medication to ward off with the side effects of the chemotherapy and immunotherapy.

The side effects for immunotherapy tend to be more extreme than those of chemotherapy. While the immune system is compromised during chemotherapy, immunotherapy has to be carefully monitored, as the body’s own immune system could decide to attack itself. This could lead to any number of health problems. Some of the side effects are the same as chemotherapy: nausea, weakness, fatigue, just to name a few. But in several patients, the immunotherapy caused them to go into ketosis and develop diabetes. Most of the side effects are reversible if caught early enough.

In order to control the side effects, most doctors prescribe a corticosteroid, to help boost the system. Occasionally the body does not respond to the lower levels of steroids and the doses must be raised as the patient becomes accustomed. The steroids have their own set of uncomfortable side effects as well, such as weight gain, acne, blurred vision and an increase in body hair.

Although immunotherapy is advancing, there is still much research and many trials in order for it to be considered a highly effective treatment for breast cancer.