Immunotherapy for cancer is an important development in medical field and is widely used in clinical practice. Let us understand about immunotherapy for cancer, its types, benefits and possible risk factors.
Immunotherapy for Cancer
Immunotherapy for cancer can be done by using certain parts of a person’s immune system to fight diseases and develop antibodies against cancer. This is usually done in the following two ways: -
- By stimulating the patient's immune system to work harder or smarter to attack cancer cells and hence cause death or lysis of malignant cancer cells.
- By providing immune system components, such as man-made immune system proteins which help in providing immunity against cancerous cells.
- In the last few decades, immunotherapy of cancer has become an important part of medical treatment for various types of carcinoma. Also, newer techniques for immune treatments are being studied and tested, for the treatment of cancer and to provide a better prognosis for the patients.
- Immunotherapy includes treatments that work in different ways and formats. Some stimulate the body’s immune system in a very general way while others help to train the immune system to attack cancer cells specifically and cause their lysis. This type of treatment may work better for some types of cancer patients than for others.
- Immunotherapy for cancer may be self- sufficient treatment for some types of cancer, but for others, it needs to be used as an adjunct therapy with other treatments like radiotherapy or chemotherapy.
- Immunotherapy for cancer can be done in different ways, either it can come through an intravenous route into the veins or as a pill that can be swallowed or a cream for rubbing on the skin. Sometimes it can be put straight into the urinary bladder of the patients in form of suppositories.
Various cancers that can be treated with immunotherapy include the following: -
- Bladder carcinoma
- Brain carcinoma
- Breast carcinoma
- Cervical carcinoma
- Colorectal carcinoma
- Gastric carcinoma
- Kidney carcinoma
- Lymphoma/Leukemia of blood cells
- Lung carcinoma
- Melanoma of skin
- Ovarian carcinoma
- Prostate carcinoma
Types of Immunotherapy for Cancer
The main types of immunotherapy for cancer, include the following techniques: -
These are the man-made version of immune system proteins and antibodies. These antibodies can be very useful in treating cancer because they are designed to attack a very specific part of a cancer cell or malignant cell in the affected area of the body. It provides associated immunity.
Types of Monoclonal Antibodies Include the Following: -
There are different types of monoclonal antibodies, which are used in immunotherapy for cancer
- Naked Monoclonal Antibodies - Naked monoclonal antibodies are antibodies that work by their own self-devised mechanism. There is no use of drugs or radioactive material involved in the process. These are the most common type of monoclonal antibodies used. These antibodies are normally attached to antigens on cancer cells, but they work by binding to antigens present on the non-cancerous cells, or even free-floating proteins. An example is alemtuzumab, it is used in immunotherapy for cancer to treat patients suffering from chronic lymphocytic leukemia (CLL).
- Conjugated Monoclonal Antibodies - Monoclonal antibodies are joined with a chemotherapy drug or any radioactive particle and hence are referred as conjugated monoclonal antibodies. These antibodies are used as a homing device so as to directly affect the malignant carcinogenic cell and destroy it. These monoclonal antibodies circulate throughout the body until it can find a target cell and get attached or hook onto that particular antigen. It then delivers the toxic or harmful substance where it is needed the most. These antibodies are better as they lessen the damage to normal cells in other parts of the body. Conjugated monoclonal antibodies are sometimes also called as tagged, labelled, or loaded antibodies. Ibritumomab tiuxetan is an example of a radiolabeled conjugated monoclonal antibody. Brentuximab vedotin is an example of chemo labelled antibodies.
- Bispecific Monoclonal Antibodies - These drug therapies are made up of parts of 2 different antibodies, meaning they can attach to two different proteins at the same time. An example is a blinatumomab, which is used to treat some types of acute lymphocytic leukemia (ALL).
Immune Checkpoint Inhibitors:
These drugs basically help the immune system to recognize and attack cancer cells. They include drugs that are often made of antibodies which help in unleashing or promoting an immune system attack on cancer cells. They’ve seen with some impressive successes rates in recent years, particularly in the patients suffering from melanoma or Hodgkin lymphoma.
Checkpoint inhibitors block these normal proteins on cancer cells, thus it leads to blockage of cancer stimulus and progression.
Three checkpoint inhibitors have been rapidly approved by the U.S. Food and Drug Administration for cancer, these include ipilimumab, pembrolizumab and nivolumab. These are one of the most promising frontiers in immunotherapy for cancer today.
These are substances induced in one's body in order to provide immunity by triggering one's immune system. This too is an important part of immunotherapy for cancer. These are usually given to healthy people which help to prevent infections or aggravation of any under pathology. Some vaccines can help prevent or treat cancer.
Traditional vaccines against carcinogenic conditions include vaccines such as HPV vaccine or human papilloma virus and hepatitis B vaccine. These vaccines, if taken in correctly and at the appropriate time provide immunity in one's body against their respective carcinomas and hence prevent those types of cancer.
In immunotherapy for cancer using vaccines, the mechanism of action occurs by separation of proteins from cancer cells and hence immunize patients against those proteins as antigens and resulting in the stimulation of one’s immune system to kill the cancer cells.
- As many cancer vaccines have failed in clinical trials, there are limited amount of vaccines available the reason may be either due to
- Too much advancement in bulky tumor deposits or suppression of immune system.
- Prior treatments may have modified tumors in many unknown ways hence causing nullification of vaccines.
- Suppressive action on immune system leading to increase in the severity of the disease.
Immunotherapy for cancer may also include other non-specific treatments. These treatments help in boosting the immune system in a normal way, but this can still help the immune system attack cancer cells. It is usually of two types: -
- Passive non- specific immunotherapy
- Active non- specific immunotherapy
Benefits of Immunotherapy for Cancer
Benefits of cancer immunotherapy include the following: -
- Useful in some cancers (like skin cancer) don’t respond well to radiation or chemotherapy but reduce and respond rapidly to immune therapy.
- Immunotherapy for cancer can act as a stimulus for other cancer treatment hence improving the results.
- Symptoms like fever, fatigue, rash, and feeling dizzy tend to be less with immunotherapy.
- Chances of cancer recurrence reduce rapidly with immunotherapy for cancer, thus leading to a better prognosis.
Possible Risk Factors of Immunotherapy for Cancer
While immunotherapy for cancer is effective in treating several types of cancers, there may be possible risk factors and harm caused by the same. Some of these problems include
- Weight gain from extra fluids
- Heart palpitations
- A stuffy head
- Harm to other organ and organ systems.
- Longer duration of action and time for full recovery.
- Full recovery may not be sure.
- The body of a person might get used to it.
Though there are a few risks associated with immunotherapy for cancer, but these are very mild when compared to other treatment approaches. Thus, it is a potential treatment approach for cancer.