For breast cancer survivors, the threat of cancer returning can be a constant concern. Modern surgeries are highly successful in removing tumors, but it’s nearly impossible to remove every last cancer cell, which can leave a patient vulnerable to developing another tumor.
The current method for killing residual cancer cells after a surgery involves radiation and chemotherapy, which is highly effective but comes with a suite of debilitating side effects.
A new vaccine to target and kill residual cancer cells in breast cancer patients could replace radiation and chemotherapy entirely. Mary Disis, a UW professor and director of the UW Medicine Cancer Vaccine Institute recently moved two major breast cancer vaccination projects to phase 1 clinical trials.
One of these vaccines, which is intended to target breast cancer stem cells, is currently in a trial with 30 patients to ensure the vaccine is safe and determine the right dosage. The other is intended to treat a type of breast cancer called ductal carcinoma in situ, (DCIS) in which the cells lining the milk ducts have become cancerous but the cancer has not invaded the surrounding breast tissue.
Disis’ research has shown that in animal models, like mice and primates, this vaccine can effectively reduce DCIS. This vaccine is also currently in a clinical trial to determine dosage and safety for patients. So far both vaccines appear very safe, only causing swelling and redness at the site of administration.
Thirty patients volunteered to work with the lab to fine-tune this experimental vaccine. Clinical trials are a vital part of any drug’s development and the first-time researchers can see how effective it is for actual patients.
“It takes a very special kind of patient to participate in a phase 1 trial,” Disis said. “It’s the generosity of people to say yes. We couldn’t do our work without it.”
The current methods of post-surgery treatment can be very taxing for patients, especially the process of receiving chemotherapy, which causes patients to experience hair loss, constant fatigue, nausea, and several other side effects. Vaccines may eliminate or lessen the need for this course of treatment after surgery.
“Now we understand why cancer evades the immune system and we can counterbalance this evasion with vaccines,” Disis said.
Harnessing the body’s immune system to tackle cancer allows for more focused treatment of the disease. Chemotherapy is a broader treatment that can attack not only cancer cells in the body, but also other healthy, quickly-dividing cells such as hair, skin, and cells in the digestive system. Immunotherapy can allow for much more specific treatment by directing a tailored immune response against cancer cells that doesn’t harm healthy human cells.
Cancer immunotherapy is a fairly new field of research, but poses exciting possibilities for many different forms of cancer including colon and ovarian cancer.
“As you go down one road for one project, many other doors open up,” Disis said.
Projects involving immunogenic treatment for these other areas are also active in Disis’ lab, conducted by Disis and other researchers who are part of the Cancer Vaccine Institute. Disis is concurrently working on colon cancer immunotherapy.
“It’s only in the last five to eight years that we’ve made leaps in understanding cancer immunotherapy,” Disis said. “It just makes it more exciting.”
As cancer immunotherapy research develops, the process is aided by advanced technology which can automate laborious techniques. Past processes also had to immunize patients one protein at a time, but now they can create comprehensive vaccines that target multiple proteins in cancer cells.
“Ten years ago very few people knew,” Disis said. “Now, immunotherapy has become part of therapy of cancers.”
The future of these vaccines depends on results over the coming years as they are tested for clinical efficacy before they can be produced for use by a wider audience of patients. If these vaccines live up to their expectation, immunotherapy would give doctors a powerful and precise tool to usher in a new era of cancer prevention.
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