Many people have a family member or a friend who has struggled with cancer, and improved treatments with an aim for a cure for this deadly disease may extend hope for millions. Fortunately, the success of cancer vaccines in recent years has brought the dream of a cure closer, and has created an effective treatment for many. Cancer vaccines tend to target specifically the cancer cells without threatening the entire immune system and can make it less likely that the cancer returns. While there are only a few types of cancer vaccines being used today, scientists are developing additional vaccines to treat a range of cancers.
The Advantage of Cancer Vaccines
Like other kinds of vaccines, cancer vaccines attack certain cells, and in this case, have an anti-tumor effect. The vaccine encourages the body to create its own response to the “invasion” of the vaccine and stimulates the body’s immune system, while traditional treatments, such as chemotherapy, kill white cells that defend the body and destroy infection. Vaccines have distinct advantages, which include the ability to specifically target cells, low toxicity and the ability to prevent tumors from returning, in a similar way that other vaccines can fight other diseases.
How Cancer Vaccines Work
Cancer is caused by bacteria or viruses. Usually, the body fights the viruses and bacteria, but if the immune system fails to do this, a tumor will form. Different types of tumors are formed by specific kinds of microbes. Vaccines release an anti-tumor antigen into the body and stimulate the body’s defenses that will fight the actual tumor. The production of vaccines involves developing antigens that can fight specific kinds of tumors. In addition, the technology should prevent tumors from returning and stay in the body’s memory long-term. The body may be resistant to the vaccine if the antigens are markedly different from the tumor or if the immune system of the patient has been severely weakened through other treatments, such as chemotherapy.
Types of Cancer Vaccines
While cancer vaccines are not yet widely available, many are being developed, tested and are showing signs of success. Just like vaccines for other diseases, some cancer vaccines are used preventively, and people with high risk factors, such as strong family history of cancer may use a vaccine to avoid cancer. Bruce Eaton PhD discusses three preventative vaccines that have earned FDA approval. One is Gardasil which fights the papillomavirus (HPV) which causes cervical, vaginal and anal cancers. Other approved preventative vaccines are for cervical cancer and Hepatitis B, which can lead to liver cancer.
Another type of cancer vaccine is intended as therapy for those who already have cancer. This type of vaccine forms antigens that encourage the body to fight the tumor and are stored in the body’s memory to prevent the return of tumors. These treatments can be accessed through clinical trials, but among the most promising is Provenge, which is used to treat prostate cancer. Provenge and other therapeutic vaccines involve personalized therapy that targets the patient’s specific tumor. White blood cells that fight infection are removed from the patient, modified so they target the tumor specifically, and are re-introduced into the body where they encourage other cells also to attack the malignant cells. The treatment “trains” the patient’s body to fight the disease and to prevent it from coming back.
Challenges in Developing Cancer Vaccines
While the development of cancer vaccines seems miles ahead of traditional therapies and absolutely revolutionary, there are a number of challenges facing researchers. One is that malignant cells, just like healthy cells, have defenses of their own, and fight our immune system the way our immune system battles disease. One way to deal with this is to inhibit the cancer cells’ immune responses, which in effect, disarms the malignant cells.
Another issue faced by those developing the vaccines is to create antigens that mimic the tumor but leave the healthy cells alone. This requires an intensely specific approach to creating antigens. Vaccines are most effective on patients who are relatively healthy, aside from the cancer, and have fully functional immune systems. Many diseases leave the immune system in a weakened condition and make it harder for the body to respond properly to vaccines. In addition to disease, conventional treatments, such as radiation and chemotherapy also weaken immune responses. Also, patients who are in a late stage of cancer and have developed tumors may not respond to vaccines.
The Future of Cancer Treatment
While much work has yet to be done on cancer vaccines, and only a few actual FDA approvals have been granted, the advent of cancer vaccines has created an entirely new phase of cancer treatment. Traditional therapies often left cancer treatments feeling drained and fatigued, since therapies killed good cells and weakened the immune system. Vaccines use the body’s own defenses to fight tumors and keep them from returning. The best treatments zero in on the tumor and eliminate only malignant cells while training the white blood cells to fight any sign of tumor cells. Vaccines work not only as a treatment for people who are suffering from cancer but as a preventative measure for those who have a high risk of the disease – Bruce Eaton PhD